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STUDY ON THE PERFORMANCE OF CONCRETE USING WASTE GLASS AND SUGARCANE BAGASSE ASH Thesis Submitted to the Punjab Agricul
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STUDY ON THE PERFORMANCE OF CONCRETE USING WASTE GLASS AND SUGARCANE BAGASSE ASH
Thesis Submitted to the Punjab Agricultural University in partial fulfillment of the requirements for the degree of
MASTER OF TECHNOLOGY in
CIVIL ENGINEERING
(Minor Subject: Computer Science and Engineering)
By Gurjit Singh (L-2013-AE-143-M)
Department of Civil Engineering
College of Agricultural Engineering and Technology
© PUNJAB AGRICULTURAL UNIVERSITY LUDHIANA-141004 2016
CERTIFICATE I This is to certify that the thesis entitled, “Study on the performance of concrete using waste glass and sugarcane bagasse ash” submitted for the degree of Master of Technology in the subject of Civil Engineering (Minor subject: Computer Science and Engineering) of the Punjab Agricultural University, Ludhiana, is a bonafide research work carried out by Gurjit Singh (L-2013-AE-143-M) under my supervision and that no part of this thesis has been submitted for any other degree. The assistance and help received during the course of investigation have been fully acknowledged.
_____________________________ (Dr. Jaspal Singh) Major Advisor Professor Department of Civil Engineering Punjab Agricultural University Ludhiana - 141004
2
CERTIFICATE II
This is to certify that the thesis entitled, “Study on the performance of concrete using waste glass and sugarcane bagasse ash” submitted by Gurjit Singh (Admn No. L-2013-AE-143-M) to the Punjab Agricultural University, Ludhiana in partial fulfillment of the requirements for the degree of Master of Technology in the subject of Civil Engineering (Minor subject: Computer Science and Engineering) has been approved by the Student’s Advisory Committee along with Head of the Department after an oral examination on the same.
_________________________ (Dr. Jaspal Singh) Major Advisor
_________________________ (Dr. Maneek Kumar) External Examiner Professor Department of Civil Engineering Thapar Institute of Engineering & Technology Patiala
_________________________ (Dr. N.K. Khullar) Head of the Department
_________________________ (Dr. Neelam Grewal) Dean Postgraduate Studies
3
ACKNOWLEDGEMENT
First of all, I bow my head to “AKAL PURKH” the ALMIGHTY by whose kindness I have been able to clear another mile stone in my life. Emotions cannot be adequately expressed in words because then emotions are transformed into mere formality. It is, indeed a great privilege to explicate my deep gratitude and respect towards my major advisor Dr. Jaspal Singh (Professor, Department of Civil Engineering) for his friendly attitude, constant encouragement, constructive criticism and critical examination of manuscript which led to the successful completion of the study. I feel elated in expressing thanks to the members of my advisory committee Dr. N.K. Khullar (Professor-cum-Head, Department of Civil Engineering, Dean PGS Nominee), Dr. S.S. Sooch (Senior Research Engineer, School of Energy Studies for Agriculture) and Er. Salam Din (Associate Professor, School of Electrical Engineering & Information Technology), for their expert advice and cooperation from time to time in conducting the research work and assisting in writing the manuscript. I am highly grateful to Er. Sarvesh Kumar (Assistance Professor, Department of Civil Engineering) who was not my committee member but still his helping hand enabled me to facilitate my thesis work. I express heartiest thanks to S. Mohanjit Singh (Lab Technician), Sh. Shiv Kumar (Lab Attendant), Sh. Jasbir Singh (Brick Layer) and other members of the technical staff of department of Civil Engineering for their help in experimental work. I am also thankful to Sh. Gurmeet Singh Soni and other Non-Teaching staff of the Department of Civil Engineering. In my opinion, God would not be everywhere; therefore, he made loving parents. A formal acknowledgement of my emotions is inadequate to convey the depth of my feeling of gratitude to my grandmother Sdn. Kartar Kaur and loving parents S. Harbans Singh Sidhu and Sdn. Parmjit Kaur. I am gracefully thankful to my sister Ramandeep Kaur and my loving wife Savreen kaur. I am forever indebted to my parents for their understanding, endless patience and encouragement when it was most required and for providing me the means to learn and understand. I have been fortunate to come across my funny & good friends without whom life would be bleak, I am happy to acknowledge the shadow support and moral upliftment showered upon me by Jagmeet, Rajindervir, Gagandeep, Devinder and Manmeet. Last but not the least, I duly acknowledge my sincere thanks to all those who love and care for me. Every name may not be mentioned but none is forgotten.
(Gurjit Singh)
4
Title of Thesis
: Study on the performance of concrete using waste glass and sugarcane bagasse ash
Name of the student and Admission No.
: Gurjit Singh L-2013-AE-143-M
Major Subject
: Civil Engineering
Minor Subject
: Computer Science and Engineering
Name and Designation of Major Advisor
: Dr. Jaspal Singh Professor, Department of Civil Engineering
Degree to be Awarded
: Master of Technology
Year of award of Degree
: 2016
Total Pages in Thesis
: 59 + Vita
Name of University
: Punjab Agricultural University, Ludhiana – 141004, Punjab, India ABSTRACT
During cement production, emission of CO2 has significant impact on environment. Apart from this, extraction of natural aggregates and generation of industrial, agricultural and domestic waste also leads to environment degradation. The use of these waste materials not only helps to reduce the use of natural resources also helps to mitigate the environment pollution. The basic objective of this research is to investigate the effect of Waste Glass (WG) as partial replacement of fine aggregates and Sugarcane Bagasse Ash (SCBA) as partial replacement of cement in concrete. This study primarily deals with the characteristics of concrete, including compressive strength, workability and thermal stability of all concrete mixes at elevated temperature. Twenty five mixes of concrete were prepared at different replacement levels of WG (0%, 10%, 20%, 30% & 40%) with fine aggregates and SCBA (0%, 5%, 10%, 15% & 20%) with cement. The water/cement ratio in all the mixes was kept at 0.55. The workability of concrete was tested immediately after preparing the concrete whereas the compressive strength of concrete was tested after 14, 28 and 60 days of curing. Based on the test results, a combination of 10% WG and 10% SCBA is the most significant for high strength and economical concrete. This research also indicates that the contribution of WG and SCBA doesn’t change the thermal properties of concrete. Keywords:
Compressive strength, Waste glass, Elevated Temperature, Sugarcane bagasse ash, Workability.
_________________________ Signature of Major Advisor
_______________________ Signature of the student
5
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6
CONTENTS
Chapter
Title
Page No.
I
INTRODUCTION
1-4
II
REVIEW OF LITERATURE
5-14
III
MATERIALS AND METHODS
15-25
3.1
General
15
3.2
Material used
15
3.2.1
Cement
15
3.2.2
Aggregate
15
3.2.2.1 Coarse aggregates
16
3.2.2.2 Fine aggregates
16
3.2.3
Sugarcane bagasse ash
16
3.2.4
Waste glass
17
3.2.5
Water
18
3.3
Methods
18
3.3.1
Methods of Concrete Mix Design
18
3.3.2
Specific gravity
18
3.3.3
Standard consistency of cement as per
19
BIS: 4031 (Part 4) - 1988 3.3.4
Determination of Initial and Final Setting time as per
19
BIS: 4031 (Part 5) - 1988 3.3.5
Compressive strength of cement as per
20
BIS: 4031 (Part 6) - 1988 3.3.6
Sieve analysis for coarse and fine aggregates as per
20
BIS: 2386 (Part 1) - 1963 3.3.7
Workability of concrete as per
20
BIS: 1199-1959 3.3.8
Compressive strength of concrete as per
22
BIS: 516 -1959 3.3.9
Compressive strength of concrete at elevated temperature
3.3.10 Statistical Analysis of compressive strength test results
7
24 24
CHAPTER
TITLE
PAGE NO.
IV
RESULTS AND DISCUSSION
26-55
4.1
Properties of Materials
26
4.1.1
Properties of cement
26
4.1.2
Properties of aggregate
26
4.1.2.1 Properties of coarse aggregates
26
4.1.2.2 Properties of fine aggregates
28
4.1.3
Properties of sugarcane bagasse ash
28
4.1.4
Properties of waste glass
28
4.2
Testing of concrete
29
4.2.1
30
Mix design of concrete by BIS recommendations
4.2.1.1 Stipulation for proportioning
30
4.2.1.2 Test for data materials
30
4.2.1.3 Target strength for mix proportioning
30
4.2.1.4 Selection of water-cement ratio
31
4.2.1.5 Selection of water content
32
4.2.1.6 Calculation of cement content
32
4.2.1.7 Proportion of volume of coarse aggregates and
32
fine aggregates 4.2.1.8 Mix calculations
33
4.2.2
33
Preparation of Trial Mixes
4.3
Workability of concrete
35
4.4
Compressive strength of concrete
37
4.5
Compressive strength of concrete at elevated temperature
41
4.6
Cost analysis
46
4.7
Statistical analysis
48
4.7.1
Analysis of variance
48
4.7.2
Multiple comparisons among replacement levels of
49
SCBA and WG 4.7.3
Development of prediction equation for compressive strength
50
of concrete and checking of developed relationship V
SUMMARY
55-56
REFERENCES
57-59
VITA
8
LIST OF TABLES
Table No.
Title
Page No.
3.1
Slump and degree of workability of concrete (Reproduced from BIS 456-2000)
22
4.1
Properties of OPC 43 grade cement
26
4.2
Properties of coarse aggregates
27
4.3
Sieve analysis for coarse aggregates (10 mm size)
27
4.4
Sieve analysis for coarse aggregates (20 mm size)
27
4.5
Sieve analysis of proportioned of coarse aggregates
27
4.6
Sieve analysis of fine aggregates
28
4.7
Chemical properties of SCBA
28
4.8
Physical properties of WG
29
4.9
Designation of concrete mix
29
4.10
Assumed standard deviation
31
4.11
Minimum Cement Content, maximum Water-Cement ratio and minimum grade of concrete for different exposures with normal weight aggregates of 20 mm nominal maximum Size
31
4.12
Maximum water content per cubic metre of concrete for nominal maximum size of aggregate
32
4.13
Volume of coarse aggregate per unit volume of total aggregate for different zone of fine aggregate.
32
4.14
Proportion of different materials
33
4.15
Quantities per cubic meter for trial mixes (M25)
34
4.16
Mix proportions of different concrete mixes
34
4.17
Test results for workability of concrete
35
4.18
Percentage loss (-) or gain (+) in workability of concrete
36
4.19
Test results for average compressive strength of concrete
38
4.20
Percentage loss (-) or gain (+) in compressive strength of concrete
39
4.21
Residual compressive strength of concrete mixes at different temperature range
41
4.23
Percentage loss in compressive strength at different temperature range
42
4.23
Cost of concrete’s ingredients
46
4.24
Cost of waste materials
47
9
4.25
Total cost of each mixture of concrete
47
4.26
Analysis of variance for various percentages of SCBA and WG for 14 days compressive strength
48
4.27
Analysis of variance for various percentages of SCBA and WG for 28 days compressive strength
48
4.28
Analysis of variance for various percentages of SCBA and WG for 60 days compressive strength
49
4.29
Multiple comparisons among different replacement levels of SCBA
49
4.30
Multiple comparisons among different replacement levels of WG
49
4.31
Measured and estimated compressive strength values of 14 days concrete
50
4.32
Measured and estimated compressive strength values of 28 days concrete
52
4.33
Measured and estimated compressive strength values of 60 days concrete
53
10
LIST OF FIGURES
Figure No.
Title
Page No.
3.1
Sugarcane bagasse ash
17
3.2
Waste glass
17
3.3
Procedure of slump test
22
3.4
Dry mixing of ingredients
23
3.5
Casting of cube specimens
23
3.6
Heating of cube specimens into muffle furnace
24
4.1
Slump values of concrete with different replacement levels of SCBA and WG
37
4.2
Compressive strength of concrete with different replacement levels of cement with SCBA and fine aggregates with WG at 14 days
40
4.3
Compressive strength of concrete with different replacement levels of cement with SCBA and fine aggregates with WG at 28 days
40
4.4
Compressive strength of concrete with different replacement levels of cement with SCBA and fine aggregates with WG at 60 days
40
4.5
Compressive strength of concrete at different temperature ranges with different replacement levels of cement with SCBA and 0% WG
43
4.6
Compressive strength of concrete at different temperature ranges with different replacement levels of cement with SCBA and 10% WG
43
4.7
Compressive strength of concrete at different temperature ranges with different replacement levels of cement with SCBA and 20% WG
43
4.8
Compressive strength of concrete at different temperature ranges with different replacement levels of cement with SCBA and 30% WG
44
4.9
Compressive strength of concrete at different temperature ranges with different replacement levels of cement with SCBA and 40% WG
44
4.10
Compressive strength of concrete at different temperature ranges with different replacement levels of fine aggregates with WG and 0% SCBA
44
4.11
Compressive strength of concrete at different temperature ranges with different replacement levels of fine aggregates with WG and 5% SCBA
45
4.12
Compressive strength of concrete at different temperature ranges with different replacement levels of fine aggregates with WG and 10% SCBA
45
4.13
Compressive strength of concrete at different temperature ranges with different replacement levels of fine aggregates with WG and 15% SCBA
45
4.14
Compressive strength of concrete at different temperature ranges with different replacement levels of fine aggregates with WG and 20% SCBA
46
11
4.15
Variation of estimated compressive strength and measured compressive strength for 14 days concrete mixes
51
4.16
Variation of estimated compressive strength and measured compressive strength for 28 days concrete mixes
53
4.17
Variation of estimated compressive strength and measured compressive strength for 60 days concrete mixes
54
12
ABBREVIATION AND SYMBOLS
SCBA
Sugarcane bagasse ash
WG
Waste glass
cm
Centimeter
g
Gram
g/cm3
Gram per cubic centimeter
BIS
Bureau of Indian Standards
Kg
Kilogram
kg/m3
Kilogram per cubic meter
kN/s
Kilonewton per second
L
Liter
L/m3
Liter per cubic meter
m
Meter
m /kg
Square meter per kilogram
mm
Millimeter
N/mm2
Newton per square millimeter
µm
Micrometer
°F
Degrees Fahrenheit
°C
Degree Celsius
%
Percent
2
13
CHAPTER I INTRODUCTION Concrete has become an indispensable part in construction works due to its mechanical and durability properties. Concrete industry is the one of the major consumer of natural resources. The utilization of concrete ingredients such as cement and aggregates has been enhanced, which ultimately results in the ill effects on the environment. Basically concrete is a composite material obtained by using cement, aggregates and water. Few decades ago, these materials were easily available while nowadays there is an adverse effect of the utilization of these materials. During the manufacturing Ordinary Portland Cement (OPC), a large amount of green house gas (CO2) is produced from both industrial and fuel combustion. In industrial process green house gas is emitted due to the heating of limestone (CaCO3) to obtain calcium oxide. During production of cement, fossil fuel combustion is also responsible for the emission of CO2 by 5%. (Fairbairn et al 2010). Due to these emissions, there is a huge incline in the temperature of the earth, which ultimately gives rise to global warming. Moreover, natural sand is another major constituent of the concrete as it is used as a fine aggregate, this also affects the natural recourses. Further with the use of river sand as a fine aggregate, leads to the exploitation of river bed, lowering the water table, erosion of land near the river and damaging the bridge structures, thereby leading to the unsustainable development of nation. Therefore, it becomes very essential and more significant to find out the substitutes for both cement and natural aggregates. Apart from it, the continuous growth of agro and industrial waste is the principle cause of many environmental problems and burdens which can be reduced by using these waste materials in concrete construction. India is agriculture based country. In the production of agriculture products, various kinds of wastes are generated like bagasse from sugarcane, wheat husk and wheat straw from wheat, groundnut shell from groundnut, rice husk from paddy etc. Most of these wastes are used as a fuel for power generation. Byproduct of this utilization is ash, which creates the disposal problem. However, this ash can be used as a useful material in concrete industry because of its chemical composition. Apart from above mentioned agrowaste ashes, some researchers identified that the sugarcane bagasse ash can also be used as pozzolan in concrete. Atomic spectrometry confirmed Sugarcane Bagasse Ash (SCBA) to be a good pozzolana since the sum of SiO2, AL2O3 and Fe2 O3, thus meeting the requirement of 70% minimum recommended by ASTM C618 (1992) (Otuoze et al 2012). The use of SCBA as a supplementary cementitious material helps to reduce the utilization of cement up to certain extent. Thus the use of bagasse ash not only helps to reduce the problem of emission of CO2 but also mitigates the problem of environmental pollution that arises during disposal of ash
from power industry. Sugarcane Bagasse Ash is one of the main by product generated by the sugar industry worldwide. Food and Agriculture Organization (FAO) states that India is the second largest producer of sugarcane after Brazil. Sugarcane bagasse is fibrous residue after the extraction of juice from the sugarcane. That fibrous residue material (Bagasse) is the major industrial waste from sugar industry. The sugarcane bagasse consists of 50% of cellulose, 25% of hemicelluloses and 25% of lignin. Each ton of sugarcane generates approximately 26% of bagasse and 0.62% of residue ash (Srinivasan and Sathiya 2010). Most of the bagasse is used as a fuel in boilers, distilleries and small amount for power generation in sugar factories. After burning of bagasse at controlled condition, by product bagasse ash
can be used as a
supplementary replacement material with cement due to high content of silica (SiO2) (cordeiro et al 2008). The use of SCBA as supplementary cementitious material (SCM) not only reduces the production of cement which is responsible for high energy consumption and carbon emission, but also can improve the compressive strength of cement based materials like concrete and mortar (Janjaturaphan and Wanson 2010). . The main improvement in compressive strength of concrete with the use of SCBA replaced with cement is due to its physical as well as chemical effects. The physical effect is filler effect, which in turn depends upon the size, shape and texture. In contrast, the chemical effect is due to its pozzolonic nature. India is the second largest populated country all over the world. Due to large number of consumers, there is a significant rise in the waste and by-products in various forms from households and industries. This obviously contaminates the natural resources like air, water and soil. In order to eradicate this problem, utilization of many waste products is now well developed, as it changes the unsustainable to sustainable development by two ways. Firstly, waste materials are utilized which otherwise will be the burden on the environment and require too much land in order to dispose them. Secondly, it will help to mitigate the problem of digging of sand. Many of industrial waste such as Waste Glass (WG), Coal bottom ash, Blast furnace slag, Copper slag etc. cause a waste disposal crisis. If fine aggregates will replaced by WG of specific size with definite ratio, it will decrease the utilization of fine aggregate. Non recyclable WG constitutes a problem for solid waste disposal in many municipalities in India. Glass is produced in various forms like container glass, flat glass, bulb glass, tube glass etc all of these glass have their limited life. Glass creates environment problem during landfills. Thus, we can use WG as fine aggregates by slight modification in their size and shape. Based on the chemistry of glass, it can be classified into various categories like vitreous silica, alkali silica, soda lime glass, borosilicate glass, lead glass and aluminosilicate glass etc. Soda lime glass is mainly used for the manufacturing of containers, jars and sheets.
2
In WG, soda lime glass is approximately about 80%. Soda Lima glass mainly consists SiO2 about 73% (Shi and Zheng 2007). Materials like WG is crushed into specified sizes for use as aggregates in various applications such as water filtration, grit plastering, sand cover for sport turf and sand replacement in concrete. The use of WG as a fine aggregate creates a problem in concrete due to the reaction of alkalis in the pores of concrete and silica from WG, which is named as alkali silica reaction (ASR). Due to ASR, silica gel is formed which absorbs water and the volume of gel increases. The swelling of silica gel generates the hydrostatic pressure. If this internal pressure exceeds the tensile strength of concrete, cracks will be formed around the concrete structures. While the use of WG as a fine aggregates, no reaction was detected whereas this reaction was detected when it is used as coarse aggregates (Shayan and Xu 2005). Thus this reaction can be eliminated by fining the size of glass particles. Fineness of glass particles will increase the surface area of glass particles favoring rapid pozzolonic reaction compared to ASR. Glass is unique inert material that can also be used in concrete as partial replacement with cement as well as with aggregates, because it contains large proportion of SiO2 that make it pozzolonic in nature (Shayan 2002). Concrete structures are massive durable structures. During their life time, they may be exposed to high temperature for example nuclear reactor, furnaces or sometimes buildings exposed to fire etc. Therefore fire resistance is also an important parameter. Inclusion of ecofriendly material towards improving properties of OPC concrete may as well require other vital properties like fire resistance. As we know the properties of concrete depends upon moisture and porosity. Sometimes concrete structures are exposed to fire, as a result their strength and durability is affected. The fire resistance of concrete is also affected by some other factors like the type of aggregates, cement and the duration of fire. The non-uniform high temperature of aggregates due to which internal pressure in aggregates develops and become the major cause of spelling of aggregates. At elevated temperature, concrete looses its strength due to formation of cracks between cement paste and aggregates thus forming thermal incompatibility between these two ingredients. Apart from this, expansion in cement paste is also observed due to their chemical composition. At elevated temperature, due to loss of water from the cement paste, free calcium hydroxide will turns in to calcium oxide. If this concrete came in contact with moisture, calcium hydroxide will form. This continuous change in volume of concrete may cause cracks in concrete structures resulting into change the durability and strength of concrete (Husem 2006). Furthermore many other factors may contribute like damaging of aggregates due to rise in temperature, weakening of cement paste due to an increase in porosity on dehydration, breakdown of the C-S-H chemical transformation on hydrothermal reactions and development of cracks (Nimyat and tok 2013). Glass cullet has different thermal properties like their temperature remains same for next 24 hours (Poutos et al 2008).
3
Therefore the present research will investigate the properties of concrete at elevated temperature inclusion with WG and SCBA. Keeping above in view, the present study has been planned with the following objectives: i)
To study the compressive strength characteristic of concrete using waste glass (as partial replacement of fine aggregates) and sugarcane bagasse ash (as partial replacement of cement).
ii)
To study the workability characteristic of concrete using waste glass and sugarcane bagasse ash.
iii)
To study the effect of elevated temperature on compressive strength of concrete using waste glass and sugarcane bagasse ash.
4
CHAPTER II REVIEW OF LITERATURE Shao et al (2000) studied the possibility of using finely ground WG as partial cement replacement in concrete. The study was examined through three sets of tests the lime-glass tests to assess the pozzolanic activity of ground glass, the compressive strength tests of concrete having 30% cement replaced by ground glass to monitor the strength development, and the mortar bar tests to study the potential expansion. The results showed that ground glass having a particle size finer than 38 mm exhibited pozzolanic behavior. The compressive strength from lime glass tests exceeded a threshold value of 4.1 MPa. The strength activity index was 91, 84, 96, and 108% at 3, 7, 28, and 90 days, respectively, exceeding 75% at all ages. The mortar bar tests demonstrated that the finely ground glass helped to reduce the expansion by up to 50%. A size effect was observed, a smaller glass particle size led to a higher reactivity with lime, a higher compressive strength in concrete and a lower expansion. Compared to fly ash concrete, concrete containing ground glass exhibited a higher strength at both early and late ages. Worell et al (2001) conducted an investigation on the emission of green house gas from global cement industries. The authors have concluded that the cement industry contributes about 5% to global anthropogenic CO2 emissions from calcination of lime stone and combustion of fuels in a kiln. Moreover, China has the largest share of total emission (33%) followed by United States (6%), India (5%), Japan (5%) and Korea (4%). Shayan (2002) studied the utilization of WG in concrete in various forms like fine aggregates, coarse aggregates, and glass powder. The author has considered that these would provide better opportunities for value adding and cost recovery as it could be used as a replacement for expensive materials such as silica fume, fly ash and cement. The use of glass powder (GLP) in concrete would prevent expansive ASR in the presence of susceptible aggregate. Strength gain of GLP-bearing mortar and concrete is satisfactory. It was concluded that 30% GLP could be incorporated as cement or aggregate replacement in concrete without any long-term detrimental effects. Up to 50% of both fine and coarse aggregate could also be replaced in concrete with acceptable strength development properties. Topcu and Canbaz (2004) studied WG as coarse aggregates in concrete. Authors analyzed the workability and strength of fresh and hardened concrete. WG as coarse aggregates do not affect the workability while the addition of waste has reduced the slump, air content, and fresh unit weight. Compressive, flexural and indirect tensile strengths values were determined on hardened concrete and were decreased as proportion of WG increased. In particular, the compressive strength decreased as much as 49% with a 60% of WG addition. It was concluded that WG was determined not to have a significant effect upon the workability
of the concrete and only slightly in the reduction of its strength. WG cannot be used as aggregate without taking into account its ASR properties. During their cost analysis they determined to lower the cost of concrete productions with replacement of WG as coarse aggregates. Park et al (2004) conducted a study on WG as fine aggregates. The authors have concluded that slump as well as compacting factor of fresh concrete decreased due to angular grain shape and air content is increased due to involvement of small size particles. Moreover, compressive, tensile and flexural strength have been reduced with increase in replacement of WG. This decline may be due to the decrease in adhesive strength between the surface of the WG aggregates and the cement paste as well as the increase in fineness modulus (FM) of the fine aggregates and the decrease in compacting factor in accordance with the increase in the mixing ratio of the WG. In any case, the colour of the WG fine aggregates did not have any notable effect on the compressive strength of the concrete. Husem (2006) studied the variation of compressive and flexural strengths of ordinary and high-performance micro-concrete at high temperatures. Compressive and flexural strengths of ordinary and high-performance micro-concrete which were exposed to high temperatures (200, 400, 600, 800 and 1000 C) and cooled differently (in air and water) were obtained. Compressive and flexural strengths of these concrete samples were compared with each other and then compared with the samples which had not been heated. On the other hand, strength loss curves of these concrete samples were compared with the strength loss curves given in the codes. Results indicate that concrete strength decreases with increasing temperature, and the decrease in the strength of ordinary concrete is more than that in highperformance concrete. The type of cooling affects the residual compressive and flexural strength, the effect being more pronounced as the temperature increases. Terro (2006) studied the effect of replacement of fine and coarse aggregates with recycled glass on the fresh and hardened concrete at ambient and elevated temperatures. The replacement of 0–100% of aggregates with fine waste glass (FWG), coarse waste glass (CWG) was under consideration. Soda- lime glass used for bottles was washed and crushed to fine and coarse aggregate sizes for use in the concrete mixes. Samples were cured at room temperatures (20–22°C), heated in the oven to the desired temperatures and allowed to cool to ambient temperatures. Then they were tested for their residual compressive strength. The compressive strength of the concrete samples made with WG was measured at temperatures up to 700°C. Moreover, the effect of the percentages of replacement with recycled glass on the slump values and initial and final setting time of concrete has also been measured. The results of this study showed that the compressive strength of concrete made with RG decreases up to 20% of its original value with increasing temperatures up to 700°C. In general, concretes made with 10% aggregates replacement with FWG and CWG had better
6
properties in the fresh and hardened states at ambient and high temperatures than those with larger replacement. Concretes made with FWG aggregates had higher compressive strengths than those made with CWG and FCWG at ambient and elevated temperatures. Souza et al (2007) studied the effects of addition of various proportions of SCBA on the properties of mortar and concrete. The ash was partial substituted (0%, 10%, 20% and 30%) with cement at constant w/c ratio of 0.5. In this study, authors conducted various test as workability with the flow table test, compressive strength at the ages of 1, 7, 14, 21 and 56 days, total water and capillary absorptions after 28 days of curing, pore size distribution at the age of 28 days, gas permeability at the ages of 1, 7, 14, 21 and 28 days and pore size distribution. In conclusion authors reported that SCBA can be replaced up to 20% and water capillary sorption increased as with the addition of SCBA. Ganesan et al (2007) conducted a study on the properties of concrete by replacing SCBA as supplementary cementitious material. In experimental study, seven different proportions of concrete mixtures (SCBA ranging from 5% to 30% by weight of cement) including the control mix were prepared with a water binder ratio of 0.53. Compressive strength of bagasse ash blended cement concrete cubes was determined after 7, 14, 28 and 90 days curing and splitting tensile strength test was conducted on SCBA blended concrete cylinders after 28 days. It was concluded that up to 20% of OPC can be replaced with wellburnt SCBA without any adverse effect on the desirable properties of concrete. Shi and Zheng (2007) concluded that the waste glass as concrete aggregates have negative effect on workability and strength. While the main concern of expansion and cracking of concrete containing glass aggregates needs to control pH of the system to prevent potential corrosion of the glass which may be achieved by replacement of cement with some pozzolonic material. The authors have seen that the combined use of other supplementary cementing materials such as coal fly ash, ground blast furnace slag and metakaolin can also decrease the expansion from alkali–aggregate reaction. Taha and Nounu (2008) studied the effect of mixed color WG as Recycled Glass Sand (RGS) and Pozzolonic Glass Powder in concrete as sand and cement replacement material respectively. Severe bleeding and segregation were observed when normal sand was replaced by RGS and the plastic properties of the concrete undergo clear changes. Due to the inherent smooth surface and negligible water absorption of glass particles, the presence of RGS in concrete will reduce the consistency of the concrete mix and adhesive bond of the ingredients inside the concrete mix. Therefore, severe bleeding and segregation were observed when natural sand was replaced by waste recycled glass sand, and plastic properties of the concrete mix undergo notable changes. No significant differences were observed in compressive strength of concrete with the presence of RGS in concrete, while an average reduction of 16% was occurred when 20% of the Portland cement was replaced by PGP.
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Bishr (2008) studied the effect of elevated temperature on the compressive strength of concrete made with silica fume (as a partial replacement of cement). Six mixture proportions were made. First was control mix (without Silica fume), and the other five mixes contained Silica fume. Cement was replaced with Silica fume by weight. The proportions of cement replaced ranged from 0% to 15%. The 100 mm cubes were casted and cured for 28 days. Three cubes of each mix proportion were placed at elevated temperature i.e. 20,150,300,500,700 and 900°C for four hours in the electric oven. The values of the compressive strength for the various mixes at elevated temperatures were measured. The results demonstrated that the compressive strength of concrete with or without silica fume decreases with increasing temperature, the peak value in the ratio of the compressive strength at high temperature to that at ambient temperature is observed around 300°C. This peak value could be attributed to the evaporation of free water inside the concrete. Cordeiro et al (2008) investigated the pozzolanic and filler effects of a residual SCBA in mortars. Initially, the influence of particle size of SCBA on the packing density, pozzolanic activity of SCBA and compressive strength of mortars was analyzed. In addition, the behavior of SCBA was compared to that of an insoluble material of the same packing density. In results, a direct relationship exists between the compressive strength of mortar containing SCBA and the Blaine fineness of the ash. On the other hand, the compressive strength of mortar containing SCBA is inversely proportional to SCBA’s particle size. According to the investigation of the SCBAs produced by vibratory grinding, the finest SCBA provided the highest packing density of mortar, which generated a higher compressive strength and pozzolanic activity. Moreover, a clear correlation was observed between Chapelle reactivity and fineness of SCBA. The pozzolanic activity of SCBA was established from the comparison with an insoluble material at the same packing density. In that case, a different behavior was verified in relation to compressive strength of mortars produced with the mineral admixtures, SCBA and quartz. After 28 days of curing, the compressive strength of SCBA mortar was 31% higher than the strength of crushed quartz mixture. This discrepancy was also observed in pozzolanic activity, mechanical response, as well as in results from the modified Chapelle method. It was concluded that the SCBA presents physico-chemical properties appropriate for its use as mineral admixture and its reactivity was mainly dependent on particle size and fineness. Behnood and Ghandehari (2009) studied the comparison of compressive and splitting tensile strength of high-strength concrete with and without polypropylene (PP) fibers heated to high temperatures. Mixtures were prepared with silica fume at 0%, 6% and 10% cement replacement and polypropylene fibers content of 0, 1, 2, and 3 kg/m3. The specimens were heated at 100, 200, 300, 400, 500 and 600°C for three hours. A strength loss was observed for all concrete mix after exposure to 600°C. The relative compressive strengths of concretes
8
containing PP fibers were higher than those of concretes without PP fibers. The splitting tensile strength of concrete was more sensitive to high temperatures than the compressive strength. Presence of PP fibers was more effective for compressive strength than splitting tensile strength above 200°C. Based on the test results, it can be concluded that the addition of 2kg/m3 PP fibers can significantly promote the residual mechanical properties of high strength concrete during heating. Chusilp et al (2009) studied the physical properties of concrete containing ground bagasse ash (BA) including compressive strength, water permeability, and heat evolution. Bagasse ash from a sugar factory was ground using a ball mill until the particles retained on a No. 325 sieve were less than 5% by weight. They were then used as a replacement for Type I Portland cement at 10%, 20%, and 30% by weight of binder. The water to binder (W/B) ratio and binder content of the concrete were held constant at 0.50 and 350 kg/m3 respectively. The results showed that at the age of 28 days, the concrete samples containing 10–30% ground bagasse ash by weight of binder had greater compressive strengths than the control concrete (concrete without ground bagasse ash) while the water permeability was lower than the control concrete. Concrete containing 20% ground bagasse ash had the highest compressive strength at 113% of the control concrete. The water permeability of concrete has decreased as the fractional replacement of ground bagasse ash increased. For the heat evolution, the maximum temperature rise of concrete containing ground bagasse ash was lower than the control concrete. It was also found that the maximum temperature rise of the concrete was reduced to 13%, 23%, and 33% as compared with the control concrete when the cement replaced by ground bagasse ash at 10%, 20%, and 30% respectively. The results indicate that ground bagasse ash can be used as a pozzolanic material in concrete with an acceptable strength, lower heat evolution, and reduced water permeability with respect to the control concrete. Turgut and Yahlizade (2009) conducted study on paving blocks using fine and coarse WG. Some of the physical and mechanical properties of paving blocks having various levels of fine glass (FG) and coarse glass (CG) replacements with fine aggregate (FA) are investigated. The test results show that the replacement of FG by FA at level of 20% by weight has a significant effect on the compressive strength, flexural strength, splitting tensile strength and abrasion resistance of the paving blocks as compared with the control sample because of pozzolonic nature of FG. The compressive strength, flexural strength, splitting tensile strength and abrasion resistance of the paving block samples in the FG replacement level of 20% are 69%, 90%, 47% and 15 % higher as compared with the control sample respectively. It is reported in the earlier works the replacement of FG by FA at level of 20% by weight suppress the alkali-silica reaction (ASR) in the concrete. The test results show that the FG at level of 20% has a potential to be used in the production of paving blocks. The
9
beneficial effect on these properties of CG replacement with FA is little as compared with FG. Cordeiro et al (2010) described the characterization of SCBA produced by controlled burning and ultrafine grinding. Initially, the optimum burning conditions of the bagasse were examined which helped to find maximum pozzolanic activity. The results demonstrated that an amorphous SCBA with high specific surface area and reduced loss on ignition can be produced with burning at 600°C in muffle oven. After observing optimum burning authors investigated the grinding procedure of SCBA. The result also shows that the grinding in vibratory mill for 120 min enabled the production of an ash with pozzolanic activity index of 100% which can be replaced cement up to 20%. Janjaturaphan and Wansom (2010) studied the pozzolanic activity of SCBA. It was found that the total amounts of SiO2, Al2O3, and Fe2O3 for all SCBAs are higher than the minimum requirement stated for Class N pozzolan (> 70%) according to ASTM C618 (2003). Although the moisture contents for all SCBAs are higher than the maximum requirement of 3%, this possesses no serious problem to the use of SCBAs as an SCM, since it can be easily reduced by oven-drying at 105-110ºC overnight or by sun-drying, for a more energy-efficient and economical means. Fairbairn et al (2010) studied the effect of cement replacement by SCBA on properties of concrete. In this study, the specimen was cured for 7, 28, 90 and 180 days for 0, 10, 15 and 20 % of cement replacement with SCBA respectively. It was concluded that an optimum of 10% SCBA blend with ordinary Portland cement could be used for reinforced concrete. Sugarcane bagasse ash (SCBA) is a pozzolan that can partially replace clinker in cement production and reduces emissions of CO2 into the atmosphere. Srinivasan and Sathiya (2010) studied the effect of SCBA as partial replacement of cement in concrete. The study was carried out on SCBA obtained by controlled combustion of sugarcane bagasse which was procured from the Tamilnadu province in India. SCBA was partial replace with cement at the ratio of 0%, 5%, 10%, 15% and 25% by weight. In the experimental work, a total of 180 numbers of concrete specimens were casted. The specimens considered in this study consisted of 36 numbers of 150 mm side cubes, 108 numbers of 150 mm diameter and 300 mm long cylinders, and 36 numbers of 750 mm x 150 mm x 150 mm size prisms. The specimens were removed from the mould after 24h and then cured under water for a period of 7 and 28 days. The study examined the compressive strength, split tensile strength, flexural strength, young’s modulus and density of concrete. It was concluded that the SCBA in blended concrete had significantly higher compressive strength, tensile strength, and flexural strength compare to that of the concrete without SCBA. It was also found that the cement could be advantageously replaced with SCBA up to maximum limit of 10%.
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Paula et al (2010) evaluated the effects of the partial replacement of OPC by SCBA in mortars. The SCBA was burned at 600°C and then at 700°C. The second burn was lasted for 3 hrs. After this burn, it was cooled naturally and then ground by using ball mill at different grinding time at different grind times (0, 30, 60, 120, 180, 300, 420, 540 and 660 min). The SCBA was replaced with cement at different replacement levels i.e. 0%, 10%, 20% and 30% in mortar proportion (1:3). The results showed that the addition of SCBA retards the setting time of mortars by 10 minutes. It was also observed that SCBA in blended mortar had significantly higher strength up-to 10% of replacement. Ismail et al (2011) studied the residual compressive strength of concrete containing palm oil fuel ash (POFA) after exposure to elevated temperatures and subsequent cooling. Specimens from ordinary Portland cement (OPC) and POFA concrete mixes were prepared and subjected to various temperature levels. The POFA concrete contains 20% partial replacement of cement by weight and the temperature levels are 100, 300, 500 and 800°C. Two cooling systems which include cooling at room temperature by the natural breeze and water-spray were involved. Compressive strength test was conducted on control specimens as well as concrete specimens revived through the two cooling systems. Physical properties accompanying thermal degradations were also assessed. Residual performance as a ratio of residual strength to original strength was evaluated. The residual performance was found to be higher in POFA concrete than in the normal concrete. In addition, water-cooling was realized to aggravate strength reduction in both normal and POFA concretes when compared with air-cooling. High temperature and cooling system were also found to have great influence on physical properties, such as mass loss, discoloration and crack patterns. Krishna et al (2011) studied the effect of elevated temperature on strength of differently cured concretes. The study investigated the effect of sustained elevated temperature on compressive strength, strength loss, weight loss, and method of curing. Ordinary Portland cement (OPC), Portland pozzolana cement (PPC), OPC with 10% replacement by micro silica were used in the experimentation. The experiments were conducted on a design M40 grade concrete mix proportions of 1:1.61:1.95, designated as mix A: 1:1.59:1.95, designated as mix B: and 1:1.595:1.95, designated as mix C: containing OPC43, PPC-43 and OPC with 10% micro silica respectively as cementing materials with a w/c ratio = 0.43. After conducting workability tests, this homogeneous concrete mass was poured into the cube moulds of size 150 x 150 x 150 mm and compacted on vibrating table. The cubes were cured for 28 days employing two different curing techniques such as conventional wet curing (curing tank) and by application of membrane forming curing compound. After 28 days of curing, the specimens were transferred to the muffle furnace wherein they were heated to 150°C, 300°C and 450°C for 1 hour. After 1 hour the cubes were air cooled to room temperature. The results revealed that the specimens of the concrete mixes: A, B and C
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suffered an increasing loss in their compressive strength on exposure to increasing sustained elevated temperatures. The loss of strength is comparable in mixes A & B while it’s more in mix C when cured by conventional water curing. Fairbairn et al (2012) observed the viability of possible CO2 emissions reductions scenarios for the cement manufacturing through the implementation of Clean Development Mechanisms (CDM) associated with the partial replacement of cement by sugar cane bagasse ash (SCBA). The prime motive of this study was to explore thermal, chemical and mechanical behavior of concretes containing 5 to 20%. This study revealed that there is improvement on the performance of all analyzed properties. Moreover, the CO2 emissions of two hypothetical scenarios of CDM Project implementation were evaluated. The analysis of the experimental results indicated that there are emission reductions on both scenarios. Lavanya et al (2012) studied the effect of SCBA as partial replacement of cement in concrete. SCBA was partially replaced with cement at the ratio of 0%, 5%, 10%, 15% and 30% for three different water cement ratios i.e. 0.35, 0.40 and 0.45. For each water cement ratio and replacement,s 3 cubes were casted and its average compressive strength is tabulated for 7, 14 and 28 days. According to the results obtained, it was concluded that SCBA can increase the overall strength of the concrete when used up to a 15% cement replacement level with w/c ratio of 0.35. SCBA is a valuable pozzolanic material and it can potentially be used as a partial replacement for cement. Otuoze et al (2012) investigated the effect of sugarcane bagasse ash (SCBA) as partial replacement of cement in concrete. In this study, a total of one hundred and eight (108) specimens in all, each measuring 100mm x 100mm x 100mm were casted. The cubes were cured for 7, 14, 21 and 28 days for 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35% and 40% SCBA blended with OPC. This study concluded that SCBA is a good pozzolana for concrete cementation and partial blends of it with OPC could give good strength development and other engineering properties in concrete. An optimum of 10% SCBA blend with OPC could be used for reinforced concrete. Higher blends of 15% and up to 35% of SCBA with OPC are acceptable for plane or mass concrete. Rukzon and Chindaprasirt (2012) studied the effect of SCBA as partial replacement of cement in high strength concrete. In the study cement was partially replaced with 10%, 20% and 30% of SCBA. For all mixes, 100 mm diameters and 200 mm height of cylindrical specimens were cast for compressive strength testing. They were tested at the ages of 7, 28 and 90 days. The results demonstrated that SCBA improves the strength of concrete. The concrete containing up to 30% of SCBA exhibited better compressive strength than conventional concrete. Ghazi (2013) studied the benefit gained from using steel fiber reinforcement on concrete mixture. The effect of fire on compressive strength was investigated. Two different tests, one of them was the non destructive test which was the
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ultrasonic pulse velocity (UPV) test and the other was the destructive compression test, were carried out using (10cm) cubes. Forty-eight cubes (half of them were with steel fiber reinforcement of fiber/concrete ratio of (0.01) by volume and the remaining cubes were without fiber reinforcement) were heated to temperature levels of (1000, 2000, 3000, 4000, 5000, 6000 and 700°C). Their after these specimens were air cooled and (UPV) test was done, the specimens were destructively tested. The results indicated that the addition of steel fiber increases the compressive strength at all tested heating levels with a maximum percentage increase of (56.9%) at a temperature level of (500°C), in spite of that they have the same behavior but the residual compressive strength decreases with the addition of steel fiber for the tested heating levels lower than (400°C) and increases for the heating levels above this degree. Madandoust and Ghavidel (2013) studied the use of the combination of WG powder (GP) and rice husk ash (RHA) as replacement for Portland cement. Hybrid mixtures containing 0-20% GP and 0-20% RHA were prepared. The best values of replacements by GP and RHA, based on the 28-days compressive strength and strength activity index, were determined as 10% and 5% respectively. From these results, the properties of hybrid concrete tended to increase with age due to the development of higher pozzolanic activity. The results also revealed good evidence that both GP and RHA can be used together in concrete without any adverse effects. Malik et al (2013) conducted study on the utilization of WG as fine aggregates in concrete. In their experimental work, authors replaced the fine aggregates by WG powder as 10%, 20%, 30% and 40% by weight. The concrete specimens were tested for compressive strength, splitting tensile strength, durability (water absorption) and density at 28 days of age and the results obtained were compared with those of normal concrete. It was concluded 20% replacement of fine aggregates by WG showed 15% increase in compressive strength at 7 days and 25% increase in compressive strength at 28 days. Fine aggregates can be replaced by WG up to 30% by weight showing 9.8% increase in compressive strength at 28 days. With increase in WG content, percentage water absorption decreases. With increase in WG content, average weight decreases by 5% for mixture with 40% WG content thus making WG concrete light weight. Workability of concrete mix increases with increase in WG content. Use of WG in concrete can prove to be economical as it is non useful waste and free of cost. Use of WG in concrete will eradicate the disposal problem of WG and prove to be environment friendly thus paving way for greener concrete. Use of WG in concrete will preserve natural resources particularly river sand and thus make concrete construction industry sustainable. Muangtong et al (2013) examined the effects of fine SCBA on the workability and compressive strength of mortars. Initially, the clinker was designed. After that it was replaced with SCBA with different replacement levels at the range of 0, 20 and 40%, whereas gypsum 13
was constant added. For cement mortars, sand, cement, SCBA and water were mixed and cast into cube moulds (50mm x 50mm x 50mm) for compressive strength and fluidity of cement mortar testing. The results revealed that replacing clinker with 20% SCBA was appropriate for production in laboratory scale and w/c ratio of 0.735 is suitable on workability of the resultant cement.
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CHAPTER III MATERIALS AND METHODS 3.1
General In this chapter, materials and methods employed to perform the study of workability,
compressive strength at room temperature and at elevated temperature of concrete containing Sugarcane Bagasse Ash and WG are discussed. 3.2
Material used
3.2.1
Cement Cement is powdery formed substance, obtained by the calcinations of lime and clay.
Apart from this, there are various minerals used to make cement like, limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand and iron ore. Bureau of Indian Standards (BIS) classified various kinds of cement according to their physical as well as chemical properties as Ordinary Portland Cement (OPC), Portland pozzolana cement, rapid hardening Portland cement, Portland slag cement, hydrophobic Portland cement, low heat Portland cement and sulphate resisting Portland cement. OPC is made by heating lime and clay at a high temperature (about1450°C) in a specially designed apparatus known as kiln. This process of heating at high temperature to obtain hard substances (clinker) from these minerals is called calcination. Thereby, this clinker is grounded with small amount of gypsum to make OPC. Chemistry of limestone and clay cement mainly consists of silicates and aluminates of limestone and clay. OPC is produced in large quantities than other cements. OPC is classified into three grades, namely 33 grade, 43 grade and 53 grade depending upon the compressive strength of cement at 28 days. In this study, Ordinary Portland Cement (OPC) conformed to BIS: 8112-2013 was used. The properties of cement were determined and the detail of which are given in Chapter IV. 3.2.2
Aggregates Aggregates are the main constituents of the concrete. Sand, gravel, and crushed
stones are used as aggregates in concrete. For a good concrete mix, aggregates need to be clean, hard, strong particles free of absorbed chemicals or coatings of clay and other fine materials that could cause the deterioration of concrete. The main function of the aggregates is to increase the volume of concrete by making rigid skeletal structure. Aggregates of different size are required to make rigid structure while their proportion may vary according to particular mix requirements. Generally aggregates can be classified as normal weight aggregates, light weight aggregates and heavy weight aggregates. Normal weight aggregates can be further classified as natural aggregates and artificial aggregates. On the basis of their size, these can be classified in to two categories such as coarse aggregate and fine aggregate.
3.2.2.1 Coarse aggregates Coarse aggregates are aggregates, the most of which are retained on 4.75-mm BIS Sieve. There are various kinds of coarse aggregates described as: i)
Uncrushed gravel or stone which results from natural disintegration of rock.
ii) Crushed gravel or stone which results from crushing of gravel or hard stone. iii) Partially crushed gravel or stone which is a product of the blending of above two The grading of the coarse aggregate is described by their nominal size i.e. 40 mm, 20 mm, 16 mm and 10 mm. Regarding the characteristics of different types of aggregate, crushed aggregates tend to improve the strength because of interlocking of angular particles, while rounded aggregates improve the flow because of lower internal friction. Crushed stone aggregates of nominal size 20 mm and 10 mm in the proportion of 50:50 were used throughout the experimental study. The aggregates were washed to remove dust and dirt and were dried to surface dry condition. The properties of coarse aggregates such as specific gravity and fineness modulus were determined and are given in Chapter IV. 3.2.2.2 Fine aggregates Fine aggregates are aggregate, the most of which pass through 4.75-mm BIS Sieve. i)
Natural sand - Fine aggregates resulting from the natural disintegration of rock and which has been deposited by streams or glacial agencies.
ii) Crushed stone sand - Fine aggregates produced by crushing hard stone. iii) Crushed gravel sand - Fine aggregates produced by crushing natural gravel. According to size, the fine aggregates may be classified as coarse, medium or fine aggregates. Depending upon the particle size distribution, the fine aggregates are divided into four grading zones as per BIS: 383-1970 that are zone I, zone II, zone III and zone IV. Sieve analysis of fine aggregates was performed and it was confirmed to grading zone II. It was brown in colour, collected from Chakki River (Pathankot). Some tests followed by BIS: 23861963 were conducted, the detail of which are given in Chapter IV. 3.2.3
Sugarcane Bagasse Ash India is an agriculture based country. Sugarcane is the one of the most cultivated crop
in all over country. Food and Agriculture Organization (FAO) states that India is the second largest producer of sugarcane after Brazil. Sugarcane Bagasse Ash (SCBA) is an agro waste, is by product of bagasse. Bagasse is fibrous residue after the extraction of sugar from sugarcane. When this bagasse is burn at controlled temperature conditions, it turns into bagasse ash.
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Figure 3.1: Sugarcane bagasse ash It has chemical composites like SiO2, AL2O3 and Fe2 O3. After burning, waste residue is collected from the boiler. To meet the requirements of replaced material, ash was sieved through 45 micron sieve. Bagasse ash used in this research was collected from the boiler of a sugar mill situated at village Budhewal, at a distance of about 4 kms from Jandaili on Ludhiana-Chandigarh road. The properties of SCBA are given in Chapter IV. 3.2.4
Waste Glass Glass in an inert material, produced in various forms. But it is not possible to recycle
the whole waste glass (WG). Thus the utilization of this waste material is very essential to generate eco friendly environment. In this study, WG was collected from various places of the city. This WG is generally known as ground glass. It includes container glass, bulb glass and flat glass. Thereafter, ground glass is wasted with water to remove dust particle and other undesirable materials from ground glass.
Figure 3.2: Waste glass After the removal of silt and other undesirable particles, it was fined to change their physical properties. To provide suitable size as fine aggregates, it was sieved through 4.75 mm sieve. After the completion of 50% passing through BIS-sieve, that ground glass was ready for the use as fine aggregates in concrete. The physical properties of glass were determined and are given in Chapter IV.
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3.2.5
Water Water is an important constituent of concrete as it is responsible for chemical reaction
with cement. Due to its importance, mixing and curing water should not contain undesirable organic substances or inorganic constituents in excessive proportions. In this project clean potable water was used for both mixing and curing of concrete. It was free from organic matter, silt, oil, sugar, chloride and acidic material as per BIS: 456-2000. 3.3
Methods The procedure of methods used for testing cement, coarse aggregates, fine aggregates
and concrete are given below: 3.3.1
Methods of concrete mix design The process of selecting suitable ingredients of concrete and determining their
relative amounts with the objective of producing a concrete of the required strength, durability and workability as economical as possible, is termed the concrete mix design. In present study mix design was done by ISI mix design method which is based on Bureau of Indian Standards BIS: 10262-2009. ISI mix design method The basic steps involved in the concrete mix design can be summarized as follows: i)
Based on the level of quality control, the target mean strength is estimated from the specified characteristic strength.
ii)
The water cement ratio is selected for the mean target strength and checked for the requirements of durability.
iii)
The water content for the required workability is determined.
iv)
The cement content can be determined from the water cement ratio and water content obtained in step (ii) and (iii) respectively and is checked for the water requirements.
v)
The relative proportion of fine and coarse aggregates is selected from the characteristic of coarse and fine aggregates.
vi)
The trial mix proportions are determined.
vii)
The trial mixes are tested for verifying the compressive strength and suitable adjustments are made to arrive at the final mix composition. The procedure of methods used for testing cement, coarse aggregates and concrete are
given below: 3.3.2
Specific gravity The specific gravity is defined as the ratio of the density (mass of a unit volume) of a
substance to the density (mass of the same unit volume) of a reference substance. The reference substance is water for liquids or air for gases. The specific gravity of the solid is the ratio of its weight in air to the difference between its weight in air and its weight after 18
immersed in water. 3.3.3
Standard consistency of cement as per BIS: 4031 (Part 4) - 1988 The standard consistency of a cement paste is defined as that consistency which will
permit a vicat plunger having 10 mm diameter and 50 mm length to penetrate to a depth of 33-35 mm from the top of the mould. i)
Weigh approximately 400 g of cement and mix it with a weighed quantity of water. The time of gauging should be between 3 to 5 minutes.
ii)
Fill the vicat mould with paste and level it with a trowel.
iii)
Lower the plunger gently till it touches the cement surface.
iv)
Release the plunger allowing it to sink into the paste.
v)
Note the reading on the gauge.
vi)
Repeat the above procedure taking fresh samples of cement and different quantities of water until the reading on the gauge is 5 mm to 7 mm. The water content for the cube is the standard consistency of cement.
3.3.4
Determination of Initial and Final Setting time as per BIS: 4031 (Part 5) - 1988
i)
Take 400 g of cement and prepare a neat cement paste with 0.85P of water by weight of cement where P is standard consistency of cement as found earlier.
ii)
Gauge time is kept between 3 to 5 minutes.
iii)
Fill the vicat mould with cement and smoothen the surface of the paste making it level with the top of the mould. The cement block thus prepared is known as test block.
iv)
For initial setting time place the test block confined in the mould and resting on non porous plate under the rod bearing needle, lower the needle gently in contact with the surface of the test block.
v)
In the beginning the needle completely pierces the test block. Repeat this procedure until the needle fails to pierce the block for about 5 mm measured from the bottom of the mould.
vi)
The period elapsing between the times when water is added to the time at which the needle fails to pierce the test block by about 5 mm is the initial setting time.
vii)
For determining the final setting time, replace the needle of vicat apparatus by the needle with an annular attachment.
viii)
The cement is considered finally set when upon applying the final setting needle gently to the surface of the block, the needle makes an impression thereon, while the attachment fails to do so. The period elapsing between the time when water is added to the cement and the time at which the needle makes an impression on the surface of the test block while the attachment fails to do so shall be the final setting time.
19
3.3.5
Compressive strength of cement as per BIS: 4031 (Part 6) - 1988 Compressive strength of cement is determined from cubes of 70.6 mm X 70.6 mm X
70.6 mm in size, made of cement mortar with one part of cement and three parts of standard sand. The quantity of materials for each cube taken as follows:Cement
:
200 g
Standard sand :
600 g
Water
(P/4+3.0) percent weight of cement and sand
:
Where P is the percentage of water required to produce a paste of standard consistency determined as found in 3.4.2 Procedure: i)
Gauge a mixture of cement and standard sand in the proportion of 1:3 by weight using (P/4+3.0) percent of water required to produce a paste of standard consistency.
ii)
Fill the cube moulds by compacting it for two minutes on a vibrating machine.
iii)
Smoothen the top surface of the cubes with flat side of trowel.
iv)
Immediately upon completion of moulding, place the cube moulds in an atmosphere of 27⁰C± 2°C.
v)
After 24 hours, remove the specimen from the moulds and keep them in water for curing till testing.
vi)
Test the cubes at 3, 7 and 28 days age in the compression testing machine.
vii)
Report the average compressive strength in N/mm2.
3.3.6
Sieve analysis for coarse and fine aggregates as per BIS: 2386 (Part 1) - 1963
i)
The sample was dried on a hot plate or in an oven at a temperature of 110ºC (230ºF).
ii)
The air dry sample was weighed and sieved successfully on the appropriate sieves starting with the large.
iii)
Each sieve was shaken separately over a clean tray until not more than a trace passes, but in any case for a period of not less than two minutes. The shaking was done with a varied motion, left to right, backward and forward, circular clockwise and anticlockwise, and with frequent jarring, so that the material is kept moving over the sieve surface in frequently changing directions.
iv)
Lumps of fine materials, if present, was broken by gentle pressure with fingers against the side of the sieve. Light brushing with a soft brush on the underside of the sieve was used to clear the sieve openings.
v)
On completion of sieving, the material retained on each sieve, together with any material cleaned from the mesh, was weighed.
3.3.7
Workability of concrete as per BIS: 1199-1959 Workability is that property of freshly mixed concrete or mortar which determines the
ease and homogeneity with which it can be mixed, placed, consolidated, and finished.
20
Workability is not just based on the properties of the concrete, but also on the nature of the application. The strength and durability of hardened concrete, in addition to labor costs, depend on concrete having appropriate workability. Workability test methods have been classified in terms of the type of flow produced during the test. Commonly used test methods are:i)
Slump Test
ii)
Compacting Factor Test
iii)
Vee Bee Consistometer Test
iv)
Flow Table Test In present study, workability was found by slump test. The concrete slump test is
used for the measurement of a property of fresh concrete. The test is an empirical test that measures the workability of fresh concrete. More specifically, it measures consistency between batches. The test is popular due to the simplicity of apparatus used and simple procedure. The apparatus consist of slump cone, scale for measurement and tamping rod (steel). The basic steps involved in Slump Test can be summarized as follows: i)
The mould for the slump test is a frustum of a cone, 300 mm of height. The base is 200 mm in diameter and it has a smaller opening at the top of 100 mm.
ii)
The base is placed on a smooth surface and the container is filled with concrete in three layers, whose workability is to be tested.
iii)
Each layer is tamped 25 times with a standard 16 mm diameter steel rod, rounded at the end.
iv)
When the mould is completely filled with concrete, the top surface is struck off (leveled with mould top opening) by means of screening and rolling motion of the tamping rod.
v)
The mould must be firmly held against its base during the entire operation so that it could not move due to the pouring of concrete and this can be done by means of handles or foot - rests brazed to the mould.
vi)
Immediately after filling is completed and the concrete is leveled, the cone is slowly and carefully lifted vertically, an unsupported concrete will now slump.
vii)
The decrease in the height of the center of the slumped concrete is called slump.
21
Figure 3.3: Procedure of slump test viii)
The slump is measured by placing the cone just besides the slump concrete and the tamping rod is placed over the cone so that it should also come over the area of slumped concrete.
ix)
The decrease in height of concrete to that of mould is noted with scale (usually measured to the nearest 5 mm.
Table 3.1:
Slump and degree of workability of concrete (Reproduced from BIS 456-2000)
Degree of Slump Use for which concrete is suitable workability mm Very low
0-25
Very dry mixes; used in road making. Roads vibrated by power operated machines.
Low
25-50
Low workability mixes; used for foundations with reinforcement. Roads vibrated by hand operated machines.
Medium
50100
Medium workability mixes; manually compacted flat slabs using crushed aggregates. Normal reinforced concrete manually compacted and heavily reinforced sections with vibrations.
High
100175
High workability concrete; for sections with congested reinforcement. Not normally suitable for vibration
3.3.8
light
Compressive strength of concrete as per BIS: 516 -1959 The quantities of cement, coarse aggregates (20 mm and 10 mm), fine aggregates,
SCBA, WG and water and for each batch (varying the percentage of SCBA and WG) were
22
weighed separately. Firstly, the cement and SCBA were uniformly mixed dry. Fine aggregates and WG were also properly mixed to this mixture in dry form. The coarse aggregates were mixed to get uniform distribution throughout the batch. Then all the ingredients were mixed thoroughly for 3 to 4 minutes.
Figure 3.4: Dry mixing of ingredients Compressive strength of concrete was determined from cubes of 150 mm X 150 mm X 150 mm in size. Cube moulds were cleaned and oil was applied. Then the concrete was filled into the cube moulds.
.
Figure 3.5: Casting of cube specimens
23
To ensure proper compaction, concrete moulds were vibrated. The surface of the concrete was finished level with the top of the mould using trowel. The finished specimens were left to harden in air for 24 hours. The specimens were removed from the moulds after 24 hours of casting and were placed in the water tank, filled with potable water in the laboratory. They were taken out from the curing tank at the ages of 14, 28 and 60 days. Surface water was wiped off and specimens were immediately tested after removal from the curing tank. The compressive strength of concrete cubes was found on Universal Testing Machine (UTM). The load was applied gradually without shock till the failure of the specimen occur and thus the compressive strength of concrete cubes was found. 3.3.9
Compressive strength of concrete at elevated temperature Compressive strength of concrete was also determined at different temperature
ranges. The cubes of 10 cm X 10 cm X 10 cm in size were used for this purpose. All the cubes were cured for 28 days prior to heating. The hardened concrete cubes were then transferred to the muffle furnace as shown in Figure 3.6(a).
(a)
(b)
Figure 3.6: Heating of cube specimens into muffle furnace They were heated from room temperature to 150°C, 300°C and 600°C for two and half hours to achieve a uniform temperature distribution across them as shown in Figure 3.6(b).After that furnace was turned off and samples were cooled to room temperature. All cooled specimens were subjected to compression test under Universal Testing Machine. 3.3.10 Statistical analysis of compressive strength test results Statistical analysis was performed on results of compressive strength test. Statistical analysis was done by using factorial Completely Randomized Design (CRD). The effect of
24
SCBA and WG on compressive strength of 14, 28 and 60 days were found out with the help of factorial CRD and critical difference was also found. The numbers of levels for SCBA and WG were five. The experiments were replicated three times. The results are given in Chapter IV.
25
CHAPTER IV RESULTS AND DISCUSSION In this chapter, results of tests conducted on materials used in research work are shown. The performance of various mixes containing different percentage of SCBA and WG is discussed. All the tests conducted were in accordance with the methods described in Chapter III. 4.1
Properties of materials The main focus of studying various properties of material used in research is to
confirm the code specification. This confirmation helps to enable an engineer to design a concrete mix for a particular strength. The following materials were used in the present research. 4.1.1
Properties of ordinary Portland cement Ordinary Portland Cement (OPC) of grade 43 was used in the research. It was fresh
and free from any lumps. To protect cement from moisture and other mixings, it was carefully stored. All basic tests like specific gravity, standard consistency, setting time, and compressive strength was conducted. These determined physical properties of the cement from various tests are listed in Table 4.1 and the corresponding standard for that parameter as per BIS: 8112-2013 is also listed in Table 4.1. Table 4.1: Properties of OPC 43 grade cement Sr. No. 1.
Characteristics Specific Gravity
Value Obtained experimentally 3.15
Values specified by BIS: 8112-2013 -
31%
-
2.
Standard consistency
3.
Initial Setting time
135 minutes
30 minutes (minimum)
4.
Final Setting time
220 minutes
600 minutes (maximum)
5.
Compressive Strength 3 days
25.54 N/mm2
23 N/mm2
7 days
36.12 N/mm2
33 N/mm2
28 days
49.53 N/mm2
43 N/mm2
The values are conforming to specifications given in BIS: 8112-2013 4.1.2
Properties of aggregates
4.1.2.1 Properties of coarse aggregates In present study, crushed gravel of two stone sizes of 10 mm and 20 mm, with equal proportions were used. The coarse aggregates were free from dust and dried to surface dry condition. As specified by BIS: 383-1970, all required properties were determined. The physical properties such as color, shape, maximum size, water absorption, sieve analysis, and fineness modulus were calculated and are given in Table 4.2, Table 4.3, Table 4.4 and Table
4.5 respectively. All coarse aggregates properties are confirming to BIS: 383-1970. Table 4.2: Properties of coarse aggregates Colour Shape Maximum Size Specific Gravity Water Absorption (%) Fineness Modulus
Grey Angular 20 mm 2.65 0.61 6.61
Table 4.3: Sieve analysis of coarse aggregates (10 mm size) Total weight of sample = 2000 g BIS- Sieve Designation 80 mm 40 mm 20 mm 12.5 mm 10 mm 4.75 mm 2.36 mm
Weight Retained on sieve (g) Nil Nil Nil 14 614 1240 105
Cumulative weight retained (g) Nil Nil Nil 14 628 1868 1973
Cumulative %age weight retained Nil Nil Nil 0.70 31.40 93.40 98.65
%age passing 100 100 100 99.30 68.60 6.60 1.35
Table 4.4: Sieve analysis of coarse aggregates (20 mm size) Total weight of sample = 2000 g BIS- Sieve Designation
Cumulative weight retained (g) Nil
Cumulative %age weight retained
%age passing
80 mm
Weight Retained on sieve (g) Nil
Nil
100
40 mm
Nil
Nil
Nil
100
20 mm
Nil
Nil
Nil
100
10 mm
1904
1904
95.20
4.80
4.75 mm
96
2000
100
0
Table 4.5: Sieve analysis of proportioned coarse aggregates BIS- Sieve Designation
50:50 Cumulative weight Proportion retained (10mm:20mm) (gm) Weight Retained
Cumulative %age weight Retained
% age passing
BIS: 383-1970 Requirements
80 mm
Nil
Nil
Nil
100
100
40 mm
Nil
Nil
Nil
100
100
20 mm
Nil
Nil
Nil
100
95-100
10 mm
1262
1262
63.10
36.90
25-55
5.45
0-10
4.75 mm 629 1891 94.55 Coarse aggregates are conforming to Table 2 of BIS: 383-1970
27
4.1.2.2 Properties of fine aggregates Natural sand was used as fine aggregates, collected from Chakki River (Pathankot). The specific gravity, water absorption and fineness modulus of fine aggregates was experimentally determined as 2.71, 1.21 and 2.70 respectively. It was brown in color with coarser shape of particles. The sieve analysis of fine aggregates is given in Table 4.6. Table 4.6: Sieve analysis of fine aggregates Total weight of sample = 500 g BIS-Sieve Designation
Weight Retained on Sieve (g)
Percentage Weight Retained on sieve
Percentage passing
Nil
Cumulative Percentage Weight Retained on sieve Nil
100
Percentage passing for Grading ZoneII as per BIS: 383-1970 100
10 mm
Nil
4.75 mm
42
8.40
8.40
91.60
90-100
2.36 mm
24
4.80
13.20
86.80
75-100
1.18 mm
70
14.00
27.20
72.80
55-90
600 micron
106
21.20
48.40
51.60
35-55
300 micron
121
24.20
72.60
27.40
8-30
150 micron
125
25.00
97.60
2.40
0-10
Fine aggregates are conforming to grading zone II as per BIS-383:1970 4.1.3 Properties of sugarcane bagasse ash The ash was obtained from the boiler of a Budhewal Co-Operative Suger Mills Ltd. situated at village Budhewal, which falls at a distance of about 4 kms from Jandaili on Ludhiana-Chandigarh road. The chemical properties of SCBA are given in Table 4.7. Table 4.7: Chemical properties of SCBA (Source: Budhewal Co-Operative Suger Mills Ltd.) Sr. No.
Chemical component
% of Chemical component
1.
SiO2
78.34%
2.
Fe2O3
3.61%
3.
Al2O3
8.55%
4.
CaO
2.15%
5.
Na2O
0.12%
6.
K2O
3.46%
7.
Ignition loss
0.42%
4.1.4
Properties of waste glass WG was collected from various places which included container glass, bulb glass and
flat glass. Thereafter, it was fined and the physical properties of glass were calculated after
28
sieving through 4.75-mm sieve. The physical properties of WG are given in Table 4.8. Table 4.8: Physical properties of WG Color Particles shape and texture Specific Gravity 4.2
Mixed color Angular and irregular 2.65
Testing of concrete In this study, the specimens were tested after 14, 28 and 60 days of curing to study
the effect of SCBA and WG in concrete while all the cubes were tested after 28 days of curing to study the effect of different temperature ranges on compressive strength of all mixtures. The 24 mixes were prepared other than control mix. The cement was replaced with different replacement levels of SCBA (0%, 5%, 10%, 15% & 20%) while fine aggregates were replaced with different ranges of WG (0%, 10%, 20%, 30% & 40%). The water/cement (w/c) ratio in all the mixes was kept 0.55. The cubes considered in this study consisted of 225 numbers of 150mm side cubes and same numbers of 100mm side cubes. The ratio of different materials used in each mix and mix designation are given below in Table 4.9. Table 4.9: Designation of concrete mixture Mix S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 S21 S22 S23 S24 S25
WG (%)
SCBA (%) 0 5 10 15 20 0 5 10 15 20 0 5 10 15 20 0 5 10 15 20 0 5 10 15 20
0
10
20
30
40
29
Cement (%) 0 95 90 85 80 0 95 90 85 80 0 95 90 85 80 0 95 90 85 80 0 95 90 85 80
4.2.1
Mix design of concrete by BIS recommendations The present investigation includes design of concrete mix for M20 grade of concrete.
The guideline given in codes BIS: 10262-2009 and BIS: 456-2000 has been adopted for mix design of concrete. 4.2.1.1 Stipulation for proportioning a)
Grade designation
:
M-20
b)
Type of cement
:
OPC 43 grade conforming to BIS 8112
c)
Maximum nominal size of aggregate
:
20 mm
d)
Minimum cement content
:
300 kg/m3
e)
Maximum water-cement ratio
:
0.55
f)
Workability
:
50 mm (slump)
g)
Degree of supervision
:
Good
h)
Type of aggregate
:
Crushed angular aggregate
i)
Maximum cement content
:
450 kg/m3
4.2.1.2 Test data for materials a)
Cement used
: OPC 43 grade conforming to BIS: 8112
b)
Specific gravity of cement
: 3.15
c)
Specific gravity of: i)
Coarse aggregate
: 2.65
ii) Fine aggregate d)
: 2.71
Water absorption i)
Coarse aggregate
: 0.61%
ii) Fine aggregate e)
: 1.21 %
Free (surface) moisture i)
Coarse aggregate
: Nil
ii) Fine aggregate f)
: Nil
Sieve analysis i)
Coarse aggregate
: Conforming to Table 2 of BIS: 383-1970
ii) Fine aggregates
: Conforming to grading Zone II of Tabl of BIS 383-1970.
4.2.1.3 Target strength for mix proportioning f 'ck = fck + 1.65 s Where f 'ck
= Target average compressive strength at 28 days
fck = Characteristic compressive strength at 28 days, and s = Standard deviation
30
From Table 4.10, standard deviation for M20 is 4 N/mm2 Therefore, target strength = 20 + 1.65 x 4 = 26.6 N/mm2 Table 4.10: Assumed Standard Deviation
(Source: Table 1 of BIS: 10262:2009)
Grade of Concrete
Assumed Standard Deviation in N/mm2
M 10
3.5
M 15
3.5
M 20
4.0
M 25
4.0
M 30
5.0
M 35
5.0
M 40
5.0
M 45
5.0
M 50
5.0
4.2.1.4 Selection of water-cement ratio Table 4.11 give values of minimum cement content, maximum water-cement ratio and minimum grade of concrete for different exposures with normal weight aggregates of 20 mm nominal maximum size. Table 4.11: Minimum Cement Content, Maximum Water-Cement Ratio and Minimum Grade of Concrete for Different Exposures with Normal Weight Aggregates of 20 mm Nominal Maximum Size (Source: Table 5 of BIS 456) Sr. Exposure No.
Plain Concrete Reinforced Concrete Minimum Maximum Minimum Minimum Maximum Minimum Cement Free W/C Grade of Cement Free W/C Grade of Content Ratio Concrete Content Ratio Concrete 3 3 kg/m kg/m 220 0.60 -300 0.55 M 20
1.
Mild
2.
Moderate
240
0.60
M 15
300
0.50
M 25
3.
Severe
250
0.50
M 20
320
0.45
M 30
4.
Very
260
0.45
M 20
340
0.45
M 35
280
0.40
M 25
360
0.40
M 40
Severe 5.
Extreme
From Table 4.11, maximum water cement ratio: 0.55 Based on experience, adopt water-cement ratio as 0.55 Maximum water cement ratio is 0.55, Hence O.K.
31
4.2.1.5 Selection of water content Table 4.12 give values of maximum water content per cubic metre of concrete for nominal maximum size of aggregate. Table 4.12: Maximum water content per cubic metre of concrete for nominal maximum size of aggregate. (Source: Table 2 of BIS: 10262-2009) Sr. No.
Maximum Size Of Aggregates
Maximum Water Content
mm
Kg
I.
10
208
II.
20
186
III.
40
165
From Table 4.12, maximum water content is 186 litre (for 25 to 50 mm slump range) for 20 mm aggregate. Based on experience, adopt 186 litres. 4.2.1.6 Calculation of cement content Water-cement ratio
= 0.55
Cement content
= 186/0.55 = 338.18 kg/m3
From Table 4.12, minimum cement content for 'mild' exposure condition is 300 kg/m3 338.18 kg/m3 > 300 kg/m3. Hence, O.K. 4.2.1.7 Proportion of volume of coarse aggregate and fine aggregate content Table 4.13 give values of volume of coarse aggregate per unit volume of total aggregate for different zone of fine aggregate. Table 4.13: Volume of coarse aggregate per unit volume of total aggregate for different zone of fine aggregate. (Source: Table 3 of BIS: 10262-2009) SI NO.
Nominal Maximum Size Aggregate
Volume Of Coarse Aggregate per unit Volume of total Aggregate for Different Zones of Fine Aggregate
Mm
Zone IV
Zone III
Zone II
Zone I
i.
10
0.50
0.48
0.46
0.44
ii.
20
0.66
0.64
0.62
0.60
iii.
40
0.75
0.73
0.71
0.69
From Table 4.13, volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone II) for water-cement ratio of 0.50 is 0.62. In present investigation water cement ratio is 0.55. Therefore, volume of coarse aggregate has to be decreased to increase the content of fine aggregate. As water cement ratio is higher by 0.05, the proportion of volume of coarse aggregate is decreased by 0.01 (at the rate of +/- 0.01 for every +/- 0.05 change in water cement ratio). Therefore, corrected
32
proportion of volume of coarse aggregates for water cement ratio of 0.55 is 0.61. 4.2.1.8 Mix calculations The mix calculations per unit volume of concrete shall be as follows: a)
Volume of concrete
:
1 m3
b)
Volume of cement
:
Mass of cement 1 Specific gravity of cement 1000
:
338.18 1 3.15 1000
=
0.107 m3
:
186 1 1 1000
=
0.186 m3
:
[a-(b+c)]
:
[1-(0.107 + 0.186 )]
=
0.707 m3
:
d Volume of coarse aggregate Specific
c)
d)
e)
Volume of water
Volume of all in aggregate
Mass of coarse aggregate
gravity of coarse aggregate 1000 :
0.707 x 0.61 x 2.65 x 1000 = 1142.87 kg
f)
Mass of fine aggregate
d Volume of fine aggregate Specific
:
gravity of fine aggregate 1000 :
0.707 x 0.39 x 2.71 x 1000 = 747.23 kg
Table 4.14: Proportion of different materials
4.2.2
Water
Cement
Fine aggregates
Coarse aggregates
186 liters
338.18 kg
747.23 kg
1142.87 kg
0.55
1
2.21
3.38
Preparation of trial mixes Based on the concrete mix design by BIS method, four trials mixes were prepared.
Two trials mixes were prepared with water cement ratio of 0.55 and other two mixes were prepared with water cement ratio of 0.50. The nine cubes were cast for each mix and were tested at 3, 7 and 28 days. The mix proportions for various constituents have been summarized in Table 4.15.
33
Table 4.15: Quantities per cubic meter for trial mixes (M20) Mix Water Water Cement Sand Coarse Average Average Average Slump No. Cement (L/m3) (kg) (kg) Aggregates cube cube cube (mm) Ratio (kg) strength strength strength at 7 at 14 at 28 days days days (N/mm2) (N/mm2) (N/mm2) MR1 0.55 186 338.18 747.23 1142.87 18.01 23.65 28.40 35 MR2
0.55
MR3
0.50
MR4
0.50
197.16 358.47 728.20
1113.77
17.72
23.57
27.73
110
372.00 716.74
1143.52
19.72
25.40
31.90
28
197.16 394.32 698.20
1113.95
18.23
23.74
29.85
86
186
The mix MR2 was chosen as the control mix because its average cube strength was very close to the target mean strength of concrete among all mixes. Furthermore, this mix also had good workability characteristics. Based on mix MR2 the mix proportions of concrete mixes are given in Table 4.16. Table 4.16: Mix proportions of different concrete mixes Mix
SCBA (%)
WG (%)
Cement SCBA Fine WG Coarse (Kg/m3) (Kg/m3) Aggregates (Kg/m3) Aggregates (Kg/m3) (Kg/m3) 358.47 0 728.20 0 1113.77
S1
0
0
S2
5
0
340.55
17.92
728.20
0
1113.77
197.16
S3
10
0
322.62
35.85
728.20
0
1113.77
197.16
S4
15
0
304.70
53.77
728.20
0
1113.77
197.16
S5
20
0
286.78
71.69
728.20
0
1113.77
197.16
S6
0
10
358.47
0
655.38
72.82
1113.77
197.16
S7
5
10
340.55
17.92
655.38
72.82
1113.77
197.16
S8
10
10
322.62
35.85
655.38
72.82
1113.77
197.16
S9
15
10
304.70
53.77
655.38
72.82
1113.77
197.16
S10
20
10
286.78
71.69
655.38
72.82
1113.77
197.16
S11
0
20
358.47
0
582.56
145.64
1113.77
197.16
S12
5
20
340.55
17.92
582.56
145.64
1113.77
197.16
S13
10
20
322.62
35.85
582.56
145.64
1113.77
197.16
S14
15
20
304.70
53.77
582.56
145.64
1113.77
197.16
S15
20
20
286.78
71.69
582.56
145.64
1113.77
197.16
S16
0
30
358.47
0
509.74
218.46
1113.77
197.16
S17
5
30
340.55
17.92
509.74
218.46
1113.77
197.16
S18
10
30
322.62
35.85
509.74
218.46
1113.77
197.16
S19
15
30
304.70
53.77
509.74
218.46
1113.77
197.16
34
Water (L/m3) 197.16
S20
20
30
286.78
71.69
509.74
218.46
1113.77
197.16
S21
0
40
358.47
0
436.92
291.28
1113.77
197.16
S22
5
40
340.55
17.92
436.92
291.28
1113.77
197.16
S23
10
40
322.62
35.85
436.92
291.28
1113.77
197.16
S24
15
40
304.70
53.77
436.92
291.28
1113.77
197.16
S25
20
40
286.78
71.69
436.92
291.28
1113.77
197.16
4.3
Workability of concrete In fresh condition, workability characteristics for high quality concrete should be
acceptable (90-100mm slump height). The desired strength of concrete can be obtained if fresh concrete has adequate slump value. In the present research, workability was measured in terms of slump values and percentage losses are shown in Table 4.17 and table 4.18 respectively. Slump values are also presented by Figure 4.1. The given data reveals that the workability of concrete decreased with increase in percentage of SCBA, while there is a huge incline in workability with increase in percentage of WG. The slump value falls down from 110 mm to 91 mm with 0% to 40% replacement of SCBA with cement, due to rough and angular shape of SCBA partials. On the other hand, as the percentage of WG is increased from 0% to 40%, slump values instantly increased from 110 mm to 133 mm. It was observed that the slump value was highest (about 133mm) at 0% replacement of SCBA with combination of 40% WG. This is mainly due to the non porous structure of the WG. Table 4.17: Test results for workability of concrete Mix
SCBA (%)
WG (%)
S1
0
110
S2
5
107
S3
10
S4
15
95
S5
20
91
S6
0
112
S7
5
104
S8
10
S9
15
95
S10
20
90
S11
0
117
S12
5
111
S13
10
S14
15
99
S15
20
97
0
10
20
35
Slump(mm)
103
101
108
S16
0
127
S17
5
119
S18
10
114
S19
15
S20
20
103
S21
0
133
S22
5
132
S23
10
S24
15
121
S25
20
119
30
40
105
123
Table 4.18: Percentage loss (-) or gain (+) in workability of concrete Mix
SCBA (%)
WG (%)
S1
0
0
S2
5
-2.72
S3
10
-6.36
S4
15
S5
20
-17.27
S6
0
+1.82
S7
5
-5.46
S8
10
-8.18
S9
15
S10
20
-18.18
S11
0
+6.36
S12
5
+0.90
S13
10
-1.82
S14
15
S15
20
-11.81
S16
0
+15.45
S17
5
+8.18
S18
10
+3.64
S19
15
S20
20
-6.36
S21
0
+20.90
S22
5
+20.00
S23
10
S24
15
+10.00
S25
20
+8.18
0
10
20
30
40
36
Slump (%)
-13.63
-13.63
-10.00
-4.54
+11.82
140 0% WG
Slump (mm)
120
10% WG
100
20% WG
80
30% WG
60
40% WG
40 20 0 0%
5%
10%
15%
20%
SCBA (%) Figure 4.1:
Slump values of concrete with different replacement levels of SCBA and WG
4.4
Compressive strength of concrete The compressive strength of all the mixes was determined at the ages of 14, 28 and
60 days for the various replacement levels of SCBA with cement and WG with fine aggregates. The values of average compressive strength and percentage loss for different replacement levels of SCBA (0%, 5%, 10%, 15%, 20%) and WG (0%, 10%, 20%, 30% and 40%) at the end of different curing periods (14 days, 28 days & 60 days) are given in Table 4.19 and Table 4.20 respectively. The effect of both waste materials on compressive strength at curing ages of 14, 28 and 60 days is illustrated by Figure 4.2 to Figure 4.4. It is quite obvious from the data that there was a gradual increase in compressive strength as the percentage of SCBA is increased up to 15%. After 15%, the value of compressive strength suddenly falls down at all curing periods. The highest percentage gain was observed at 10% SCBA replacement level, it was about 4.6, 6.1 and 5.9 at 14, 28 and 60 days curing respectively. Nevertheless, the replacement of 15% of SCBA still improves the compressive strength of concrete as compared to the control concrete but for much better results, the 10% of SCBA seems to be the optimum. This improvement is basically due to physical as well as chemical effect of SCBA. The chemical effect is mainly due to the reaction between the reactive silica and calcium hydroxide whereas the physical effect relates to the finer particle of SCBA. In contrast, there was a loss in strength of concrete due to replacement of fine aggregates with WG. The substitution of WG produced relatively low strength concrete compared to control mix. This decline may be due to the decrease in adhesive strength between the surface of the WG aggregates and the cement paste as well as the increase in fineness modulus (FM) of the fine aggregates and the decrease in compacting factor in accordance with the increase in the mixing ratio of the WG. At the curing age of 14 days, there was about 0.6%, 2.5%, 5.9% and 8.1% loss in compressive strength of concrete
37
containing 10%, 20%, 30%, and 40% WG as fine aggregates respectively. The same trend was observed for curing period of 28 and 60 days. It can be seen that the loss in compressive strength was minor up to 10% of WG but beyond 10%, there was large reduction in compressive strength. From Table 4.19 and Table 4.20, it can be concluded that the combination of 10% SCBA and 20% WG gives better results without any loss in strength. In order to make higher strength concrete compared to reference mix, the combination of 10% SCBA and 10% WG is the most significant. Table 4.19: Test results for average compressive strength of concrete Average compressive strength (N/mm2) of concrete for different curing days 14 days 28 days 60 days
Mix
SCBA (%)
WG (%)
S1
0
23.01
27.35
32.10
S2
5
23.63
28.41
33.44
S3
10
24.06
29.01
33..99
S4
15
23.33
27.86
32.42
S5
20
22.84
26.93
31.81
S6
0
22.87
27.10
31.93
S7
5
23.51
28.17
33.28
S8
10
23.92
28.79
33.86
S9
15
23.21
27.65
32.32
S10
20
22.71
26.74
31.61
S11
0
22.43
26.55
31.23
S12
5
23.05
27.59
32.64
S13
10
23.53
28.19
33.15
S14
15
22.73
27.11
31.42
S15
20
22.29
26.11
30.84
S16
0
21.65
25.79
30.14
S17
5
22.25
26.83
31.45
S18
10
22.68
27.21
32.00
S19
15
21.99
26.28
30.49
S20
20
21.46
25.68
30.10
S21
0
21.14
24.80
29.17
S22
5
21.79
25.84
30.49
S23
10
22.23
26.50
31.04
S24
15
21.44
25.27
29.56
S25
20
20.96
24.36
29.30
0
10
20
30
40
38
Table 4.20: Percentage loss (-) or gain (+) in compressive strength of concrete Mix
SCBA (%)
WG (%)
Percentage loss (-) or gain (+) in compressive strength for different curing days 14 days 28 days 60 days
S1
0
0
0
0
S2
5
+2.7
+3.9
+4.2
S3
10
+4.6
+6.1
+5.9
S4
15
+1.4
+1.9
+1.0
S5
20
-0.7
-1.5
-0.9
S6
0
-0.6
-0.9
-0.5
S7
5
+2.1
+3.01
+3.6
S8
10
+3.9
+5.3
+5.5
S9
15
+0.9
+1.1
+0.7
S10
20
-1.3
-2.2
-1.5
S11
0
-2.5
-2.9
-2.7
S12
5
+0.2
+0.9
+1.7
S13
10
+2.3
+3.1
+3.3
S14
15
-1.2
-0.9
-2.1
S15
20
-3.1
-4.5
-3.9
S16
0
-5.9
-5.7
-6.1
S17
5
-3.3
-1.9
-2.0
S18
10
-1.4
-0.5
-0.3
S19
15
-4.4
-3.9
-5.0
S20
20
-6.7
-6.1
-6.2
S21
0
-8.1
-9.3
-9.1
S22
5
-5.3
-5.5
-5.0
S23
10
-3.4
-3.1
-3.3
S24
15
-6.8
-7.6
-7.9
S25
20
-8.9
-10.9
-8.7
0
10
20
30
40
39
Compressive Strength (N/mm2)
25 24 23
0% WG
22
10% WG
21
20% WG
20
30% WG
19
40% WG
0% SCBA
5% SCBA
10% SCBA
15% SCBA
20% SCBA
SCBA (%)
Figure 4.2:
Compressive strength of concrete with different replacement levels of cement with SCBA and fine aggregates with WG at 14 days
Compressive Strength (N/mm2)
30 29 28 27
0% WG
26
10%WG
25
20% WG
24
30% WG
23
40% WG
22 0% SCBA
5% SCBA
10% SCBA
15% SCBA
20% SCBA
SCBA (%)
Compressive Strength (N/mm2)
Figure 4.3:
Compressive strength of concrete with different replacement levels of cement with SCBA and fine aggregates with WG at 28 days
35 34 33 32 31 30 29 28 27 26
0% WG 10% WG 20% WG 30% WG 40% WG
0% SCBA
5% SCBA
10% SCBA
15% SCBA
20% SCBA
SCBA (%)
Figure 4.4:
Compressive strength of concrete with different replacement levels of cement with SCBA and fine aggregates with WG at 60 days
40
4.5
Compressive strength of concrete at elevated temperature In the present study, the compressive strength was measured both at room
temperature and elevated temperature. The residual compressive strength and percentage loss in compressive strength of all concretes mixes at room temperature and after heating to 150°C, 300°C and 600°C is given in Table 4.21 and Table 4.22 respectively. The effect of elevated temperature and replacement of waste materials on compressive strength at curing age of 28 days is illustrated by Figure 4.5 to Figure 4.14. It is quite obvious from the given data that the compressive strength of all concrete mixes decreases with increase in temperature. The strength of concrete with 0% replacement of SCBA and WG after heating to150°C, 300°C and 600°C was 81.0%, 84.0%, and 39.1% of its unheated strength respectively. Almost similar trend was observed in SCBA and WG concrete mixes also. At 1500, the reduction in compressive strength was lower as compared to other temperature ranges. At the replacement level of 20% SCBA and 20% WG, the loss in strength was the higher as compared to other replacement level. There was approximately 15% to 19% strength loss as the temperature was increased to 3000 C In concrete mix (S19) containing 15% SCBA and 30% WG, there was the highest loss of strength about (62.1%) at 6000. In contrast at 15% SCBA and 20% WG replacement level, the percentage loss of strength was the lowest at same temperature condition. The loss of strength in all concrete mixes is mainly due to the evaporation of water. As water evaporates from cubes, cracks are developed due to internal pressure. Moreover, the other reason behind this cracking is the expansion of aggregates at higher temperature due to evaporation of water. As water evaporates, it contracts the cement paste, ultimately affecting the bonding of concrete. Table 4.21: Residual compressive strength of concrete mixes at different temperature Mix
SCBA (%)
S1 S2 S3 S4 S5 S6 S7 S8 S9 S10
0 5 10 15 20 0 5 10 15 20
WG (%)
0
10
Residual compressive strength (N/mm2) at different temperature ranges Room 150°C 300°C 600°C Temperature (R.T.) 29.35 26.71 24.66 11.45 30.26 26.93 25.11 12.41 31.38 28.86 26.36 13.18 30.22 26.59 24.78 12.09 29.02 26.12 24.09 11.32 29.14 26.19 23.63 11.30 30.08 26.10 25.17 12.12 31.14 27.12 26.25 13.01 29.99 26.66 24.62 11.96 28.79 25.73 24.03 11.17
41
S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 S21 S22 S23 S24 S25 Table 4.22:
0 5 10 15 20 0 5 10 15 20 0 5 10 15 20
28.64 29.61 30.64 29.52 28.29 27.58 28.46 29.29 28.44 27.32 26.91 27.85 28.99 27.73 26.53
20
30
40
25.86 26.20 27.91 25.94 24.44 24.24 25.18 26.21 25.68 24.12 23.62 24.20 25.16 24.43 23.79
23.34 25.67 25.82 23.94 23.70 23.33 23.28 23.75 23.40 22.97 22.01 22.92 24.20 23.37 22.04
10.88 11.99 12.74 12.57 11.40 10.97 11.12 11.80 10.77 10.40 10.62 11.50 12.20 11.42 10.58
Percentage loss in compressive strength at different temperature
Mix
SCBA (%)
S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 S21 S22 S23 S24 S25
0 5 10 15 20 0 5 10 15 20 0 5 10 15 20 0 5 10 15 20 0 5 10 15 20
WG (%)
0
10
20
30
40
Percentage loss in compressive strength with increase in temperature Room Room Room Temperature Temperature Temperature to 150°C to 300°C to 600°C 9.0 15.9 60.9 11.0 17.0 58.9 8.0 15.9 57.9 12.0 18.0 59.9 9.9 16.9 60.9 10.1 18.9 61.2 13.2 16.3 59.7 12.9 15.7 58.2 11.1 17.9 60.1 10.6 16.5 61.2 9.7 18.5 62.0 11.5 15.3 59.5 8.9 15.7 58.4 12.1 18.9 57.4 13.6 16.2 59.7 12.1 15.4 60.2 11.5 18.2 60.9 10.5 18.9 59.7 9.7 17.7 62.1 11.7 15.9 61.9 12.2 18.2 60.5 13.1 17.7 58.7 13.2 16.5 57.9 11.9 15.7 58.8 10.5 16.9 60.1
42
Compressive Strength (N/mm2)
600°C 40 30 20 10 0
300°C 150°C R.T 150… 300… 0% SCBA
5% SCBA
10% SCBA
R.T
600… 15% SCBA
20% SCBA
SCBA (%)
Compressive Strength (N/mm2)
Figure 4.5:
Compressive strength of concrete at different temperature ranges with different replacement levels of cement with SCBA and 0% WG
40 30
600°C
20 R.T 150°C 300°C 600°C
10 0 0% SCBA 5% SCBA
10% SCBA
15% SCBA
300°C 150°C R.T
20% SCBA
SCBA (%)
Compressive Strength (N/mm2)
Figure 4.6:
Compressive strength of concrete at different temperature ranges with different replacement levels of cement with SCBA and 10% WG
40 30
600°C
20 R.T 150°C 300°C 600°C
10 0 0% SCBA 5% SCBA
10% SCBA
15% SCBA
300°C 150°C R.T
20% SCBA
SCBA (%)
Figure 4.7:
Compressive strength of concrete at different temperature ranges with different replacement levels of cement with SCBA and 20% WG
43
Compressive Strength (N/mm2)
30 20
600°C
10
R.T 150°C 300°C 600°C
0 0% SCBA 5% SCBA
10% SCBA
15% SCBA
300°C 150°C R.T
20% SCBA
SCBA (%)
Compressive Strength (N/mm2)
Figure 4.8:
Compressive strength of concrete at different temperature ranges with different replacement levels of cement with SCBA and 30% WG
30 20
600°C
10
R.T 150°C 300°C 600°C
0 0% SCBA 5% SCBA
10% SCBA
15% SCBA
300°C 150°C R.T
20% SCBA
SCBA (%)
Compressive Strength (N/mm2)
Figure 4.9:
Compressive strength of concrete at different temperature ranges with different replacement levels of cement with SCBA and 40% WG
30 20
600°C
10
R.T 150°C 300°C 600°C
0 0% WG
10% WG
20% WG
30% WG
300°C 150°C R.T
40% WG
WG (%)
Figure 4.10: Compressive strength of concrete at different temperature ranges with different replacement levels of fine aggregates with WG and 0% SCBA
44
Compressive Strength (N/mm2)
40 30
600°C
20 R.T 150°C 300°C 600°C
10 0 0% WG
10% WG
20% WG
30% WG
300°C 150°C R.T
40% WG
WG (%)
Compressive Strength (N/mm2)
Figure 4.11: Compressive strength of concrete at different temperature ranges with different replacement levels of fine aggregates with WG and 5% SCBA
40 30
600°C
20 RT 150°C 300°C 600°C
10 0 0% WG
10% WG
20% WG
30% WG
300°C 150°C RT
40% WG
WG (%)
Compressive Strength (N/mm2)
Figure 4.12:
Compressive strength of concrete at different temperature ranges with different replacement levels of fine aggregates with WG and 10% SCBA
40 30
600°C
20
300°C R.T 150°C 300°C
10 0 0% WG
10% WG
150°C R.T
600°C
20% WG
30% WG
WG (%)
40% WG
Figure 4.13: Compressive strength of concrete at different temperature ranges with different replacement levels of fine aggregates with WG and 15% SCBA
45
Compressive Strength (N/mm2)
30 25 20 15 10 5 0
600°C
0% WG
10% WG
20% WG
R.T 150°C 300°C 600°C 30% WG
300°C 150°C R.T
40% WG
WG (%)
Figure 4.14: Compressive strength of concrete at different temperature ranges with different replacement levels of fine aggregates with WG and 20% SCBA 4.6
Cost analysis Cost analysis of concrete can be done by multiplying the cost of concrete ingredients
with their respective quantity. However, the cost of concrete ingredients depends upon the transportation charges as well as manufacturing charges. While, it is not relevant to include transportation charges because transportation price depends on the distance between manufacturing place and delivery destination. Thus, in present research the cost analysis of concrete has been done without considering the transportation expenditure (Table 4.23 to Table 4.25). The present results depicts that the cost of concrete decreases as percentage of SCBA increases while there is no change in the cost of concrete during replacement of WG. The cost of concrete remains same as the reference mix at every replacement level. In mixes S5, S10, S15, S20, and S25, about 11.3% reduction is observed while at the same time strength of concrete also decreases. Moreover, mix S8 and S13 reduces 5.7 percent cost of concrete which is recommended for higher strength and acceptable workability. Therefore, this analysis spreads the awareness towards the use of these waste materials in concrete which provides economic benefits for concrete industries. Table 4.23:
Cost of concrete’s ingredients (without considering transportation expenditure)
Sr. No 1
Ingredients
Cost (Rs/Kg)
Cement
4.60
2
Fine Aggregates
0.20
3
Coarse Aggregates
0.14
46
Table 4.24: Cost of Waste Materials (without considering transportation expenditure) Sr. No 1
Waste Materials SCBA
Grinding Charges 1.50
Total Cost (Rs/Kg) 1.50
2
WG
0.20
0.20
Table 4.25: Total Cost of each mixture of concrete
0
Coarse Aggregates (Rs/m3) 155.92
Total Cost (Rs/m3) 1950.52
Percentage decrease in cost 0
145.64
0
155.92
1894.97
2.8
53.78
145.64
0
155.92
1839.39
5.7
1401.62
80.66
145.64
0
155.92
1783.83
8.5
S5
1319.19
107.54
145.64
0
155.92
1728.29
11.3
S6
1648.96
0
131.07
14.56
155.92
1950.51
0
S7
1566.53
26.88
131.07
14.56
155.92
1894.96
2.8
S8
1484.05
53.78
131.07
14.56
155.92
1839.38
5.7
S9
1401.62
80.66
131.07
14.56
155.92
1783.82
8.5
S10
1319.19
107.54
131.07
14.56
155.92
1728.28
11.3
S11
1648.96
0
116.51
29.12
155.92
1950.51
0
S12
1566.53
26.88
116.51
29.12
155.92
1894.96
2.8
S13
1484.05
53.78
116.51
29.12
155.92
1839.38
5.7
S14
1401.62
80.66
116.51
29.12
155.92
1783.82
8.5
S15
1319.19
107.54
116.51
29.12
155.92
1728.28
11.3
S16
1648.96
0
101.94
43.69
155.92
1950.51
0
S17
1566.53
26.88
101.94
43.69
155.92
1894.96
2.8
S18
1484.05
53.78
101.94
43.69
155.92
1839.38
5.7
S19
1401.62
80.66
101.94
43.69
155.92
1783.82
8.5
S20
1319.19
107.54
101.94
43.69
155.92
1728.28
11.3
S21
1648.96
0
87.38
58.25
155.92
1950.51
0
S22
1566.53
26.88
87.38
58.25
155.92
1894.96
2.8
S23
1484.05
53.78
87.38
58.25
155.92
1839.38
5.7
S24
1401.62
80.66
87.38
58.25
155.92
1783.82
8.5
S25
1319.19
107.54
87.38
58.25
155.92
1728.28
11.3
Mix
Cement (Rs/m3)
SCBA (Rs/m3)
WG (Rs/m3)
0
Fine Aggregates (Rs/m3) 145.64
S1
1648.96
S2
1566.53
26.88
S3
1484.05
S4
47
4.7
Statistical analysis
4.7.1
Analysis of variance The effect of various percentages of SCBA and WG for 14, 28 and 60 days of
compressive strength was statistically determined using factorial CRD at 5% level of significance. The analysis of variance for various percentages of SCBA and WG for 14, 28 and 60 days of compressive strength of concrete are given in Table 4.26, Table 4.27 and Table 4.28 respectively. Table 4.26: Analysis of variance for various percentages of SCBA and WG for 14 days compressive strength Mean Values of 14 days compressive strength in N/mm2 SCBA%
WG 0%
WG 10%
WG 20%
WG 30%
WG 40%
23.01
22.87
22.43
21.65
21.14
5%
23.63
23.51
23.05
22.25
21.79
10%
24.06
23.92
23.53
22.68
22.23
15%
23.33
23.21
22.73
21.99
21.44
20%
22.84
22.71
22.29
21.46
20.96
0%
Critical difference for SCBA at 5% level of significance = .79 Critical difference for WG at 5% level of significance
=.79
Coefficient of variation = 4.81 Table 4.27: Analysis of variance for various percentages of SCBA and WG for 28 days compressive strength Mean Values of 28 days compressive strength in N/mm2 SCBA%
WG 0% 27.35
WG 10% 27.10
WG 20% 26.55
WG 30% 25.79
WG 40% 24.80
5%
28.41
28.17
27.59
26.83
25.84
10%
29.01
28.79
28.19
27.21
26.50
15%
27.86
27.65
27.10
26.28
25.27
20%
26.93
26.74
26.11
25.68
24.36
0%
Critical difference for SCBA at 5% level of significance = .58 Critical difference for WG at 5% level of significance Coefficient of variation = 2.97
48
= .58
Table 4.28: Analysis of variance for various percentages of SCBA and WG for 60 days compressive strength Mean Values of 60 days compressive strength in N/mm2 SCBA% WG 0% WG 10% WG 20% WG 30% WG 40% 0%
32.10
31.93
31.23
30.14
29.17
5%
33.44
33.28
32.64
31.45
30.49
10%
33..99
33.86
33.15
32.00
31.04
15%
32.42
32.32
31.42
30.49
29.56
20%
31.81
31.61
30.84
30.10
29.30
Critical difference for SCBA at 5% level of significance = .55 Critical difference for WG at 5% level of significance
= .55
Coefficient of variation = 2.38 4.7.2
Multiple comparisons among replacement levels of SCBA and WG As we know that the analysis of variance gives only whether there are significant
differences among treatments in the experiments as a whole but it does not tell us which treatments differ from one another. So we do Post Hoc tests to find out pair wise comparison. In present situation, Tukey’s method was used. The comparisons have been done according to different replacement levels of SCBA and WG. This analysis is given in Table 4.29 and Table 4.30. The figures followed different superscripts are significantly different (p