ABSTRACT
Rice husk ash and saw dust ash are good materials that can supplement cement to some extent but the percentage of saw dust ash and rice husk ash should not be more than 15% of cement. For a given mix, the water requirement increase as the rice husk ash and saw dust ash content increases. The increased water demand is as a result of increased carbon content. This is because the carbon content of ordinary Portland cement is very small compared to that in Rice husk ash and Saw dust ash. So as ash is introduced into the mix, the carbon content increases and the water requirement also increases. The setting time of concrete with saw dust ash and rice husk ash increases as the ash content increases: The compressive strength of the concrete cubes for all mix increases with age at curing and decreases as the rice husk ash and saw dust ash content increases. This addition of rice husk ash and saw dust as is permitted for lightweight structure. All materials used for the practical are local materials and they are readily available and they can also reduce the cost of producing concrete when implemented. There has been no issue of hazardous emission generated from this material when used for construction. The mode of disposing rice husk ash and sawdust has been by open air burning which has harmful effect on the people and environment at large but with its implementation in lightweight structure, it will help in providing clean and safe environment.
TABLE OF CONTENTS
PAGE
Title page i
Declaration ii
Certification iii
Dedication iv
Acknowledgments v
Table of contents vi
List of tables viii
List of figures ix
Abstract x
CHAPTER 1: INTRODUCTION
1.1 Background of Study 1
1.2 Aim of Study 3
1.3 Objective of Study 4
1.4 Scope 4
1.5 Justification 5
CHAPTER 2: TWO: REVIEW OF RELATED LITERATURE
2.1 Pozolanic Material 7
2.1.1 Types of pozzolans 8
2.1.2 Fly ash as pozzolan 8
2.1.3 Silica fume (SF) as a pozzolan 9
2.1.4 Rice husk ash as a pozzolan 9
2.1.5 Other pozzolans and applications 10
2.2 Admixtures 11
2.2.1 Types of admixtures 12
2.2.2 Chemical admixtures 12
2.2.3 Mineral admixtures in concrete 13
2.3 Works Done on Partial Replacement of Cement in Concrete
2.3.1 Rice husk ash as supplementary cementitious material for cement 13
2.3.2 Rice husk ash as a pozzolanic material 14
2.3.3 Effect of rice husk ash (RHA) as partial replacement of cement on concrete properties 14
2.3.4 Optimization for the use of rice husk ash and sawdust as alternative binder for concrete 15
2.3.5 Saw dust ash as partial replacement for cement in concrete 17
CHAPTER 3: MATERIALS AND METHODS 3.1 Location and Preparation of Study Material 21
3.2 Preparation of Materials 22
3.3 Testing of Study Material 22
3.3.1 Determination of particle size distribution of the aggregate (coarse and fine) 22
3.3.2 Determination of specific gravity of aggregate (coarse and fine) 24
3.3.2.1 Procedure for fine aggregate test 24
3.3.2.2 Procedure for coarse aggregate test 25
3.3.2.3 Specific gravity for cement, rice husk ash and saw dust ash 26
3.4 Concrete Mix Design 27
3.4.1 Batching and mixing of concrete 27
3.4.2 Casting of cube samples 27
3.5 Setting time of cement 27
3.6 Hardened Concrete Test 29
3.6.1 Density test 29
3.6.2 Compressive strength 29
3.6.3 Dry and water absorption test 29
3.7 Testing of Concrete Cubes (Compressive Strength Test) 30
CHAPTER 4: RESULTS AND DISCUSSION
4.1 Discussion of Results 33
CHAPTER 5: CONCLUSION
5.1 Conclusion 59
References 60
LIST OF TABLES
4.1: Chemical analysis of RHA and SDA. 32
4.2: Result of particle size distribution test (fine aggregate) 33
4.3: Result of particle size distribution test (coarse aggregate) 34
4.4: Specific gravity for coarse aggregate 35
4.5: Specific gravity of fine aggregate 35
4.6a: Specific gravity for ordinary portland cement (dangote) 36
4.6b: Specific gravity of RHA 36
4.7: Specific gravity of SDA 37
4.8: Slump test result of SDA 38
4.9: Slump test result of SDA/RHA 38
4.10: Result of Initial of final setting time of OPC/SDA paste 39
4.11: Result of initial and final setting of OPC/SDA/RHA paste 39
4.12: Result of compressive strength obtained with 0% replacement of cement with sawdust ash (SDA) 40
4.13: Result of compressive strength obtained with 5% replacement of cement with SDA 41
4.14: Result of compressive strength obtained with 10% replacement of cement with SDA 42
4.15: Result of compressive strength obtained with 20% replacement of cement with SDA 44
4.16: Result of the compressive strength obtained with 30% replacement of cement with SDA 46
4.17: Result of compressive strength obtained with 40% replacement of cement with SDA 48
4.18: Result of the compressive strength obtained with 5% replacement of cement with SDA and RHA 50
4.19: Result of compressive strength obtained with 10% replacement of cement with SDA and RHA 51
4.20: Result of compressive strength obtained with 20% replacement of cement with SDH and RHA 53
4.21: Result of compressive strength obtained with 30% replacement of cement with SDA and RHA 54
4.22: Result of compressive strength obtained with 40% replacement of cement with SDA and RHA 55
LIST OF FIGURES
4.1: Graph of particle Size distribution test (fine aggregate) 32
4.2: Graph of particle Size distribution test (coarse aggregate) 33
4.3: Graph of setting time of cement 43
4.4: Graph of compressive strength at 3 days curing age 45
4.5: Graph of compressive strength at 7 days curing age 47
4.6: Graph of compressive strength at 28 days curing age 49
4.7: Graph of compressive strength at 60 days curing age 49
4.8: Graph of compressive strength at 90 days curing age 51
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF STUDY
Concrete is the most mainstream building material in the world. Concrete is known to be the most wide spread fundamental material because of its quality to take care of various geometrical configurations. It is a collection of cement, fine and coarse aggregates and water. Over three hundred million tons of manufacturing wastes are being process problems of discarding, health menaces and aesthetic difficulties. The global utilization of cement is too high because of its extensive importance in concrete (Oluremi, 2014). Over five billion tons of cement is manufactured in the world each year. However, the cement production is gradually consuming the limestone reserves worldwide and also characterized by high energy consumption. River sand has been the most widespread choice for the fine aggregate element of concrete in the past, but excess exploitation of the resource has led to environmental concerns, the exhausting of protectable river sand resources and an associated price increase in the cost of the material. Thus, there is the need for the pursuit of materials locally as alternative materials for the construction of workable but low-cost buildings in both rural and urban areas (Al-Dulaijan, et al., 2002).
Construction industries are under pressure to pinpoint alternative materials to replace the ever growing demand for sand and cement. On the other hand, the advantages of use of by products or aggregates acquired as discarded materials are obvious in the aspects of lessening environmental load and waste controlling cost, reducing production cost as well as enhancing of concrete. To overcome the pressure of demand for natural acceptable aggregate and cement, scientists and specialists in the construction businesses have recognized some alternative materials such as fly ash, slag, limestone-powder, siliceous resources, sawdust ash and rice husk ash.
Concrete is taken as the most extensively used man made building material and studies show that it will continue to be so in the next millennia to come. Round the world yearly concrete utilized is about five billion tons, enough for close to one ton for every individual each year, at about the volume of 400 liters per individual. Such usefulness of concrete is due to the fact that from the collective constituents, namely, cement, aggregate and water, it is imaginable to adapt the properties of concrete so as to meet the demands of any specific situation (Kamran, 2013). The progresses in concrete technology has created opportunities for the advancement in the use of the locally available materials by cautious mix proportioning and appropriate workmanship, so as to give rise to a concrete meeting the performance requirements. Scientists, Engineers and Technologists are thus in constant lookout for materials which can serve as alternatives for the regular materials or which have those properties as would support its usage for new designs and innovations. Concretes using substitute materials fall under the initial category. The raw materials for the production of cement and aggregates are basically limitless, since almost all of earth’s crust can be consumed, if related costs and energy requirements can be conformed with. This course of achievement cannot be taken as there are other limitations that merit closer examination. One question is therefore asked: Is the recycling of waste products into a new building material whose binder ability is not Portland cement and whose aggregates may not be organic is a viable headway? Perhaps the response is confirmatory since planned utilization of waste products importantly helps to maintain balance ecologically.
In this research, cement was in part substituted with sawdust including rice husk ash as 5%, 10% 15% and 20% and 25% by weight. Concrete specimens were verified for slump test, compressive strength, durability (water absorption) and light weight nature for diverse rice husk ash plus sawdust ash percentages. The results obtained were matched with those of regular M-25 concrete mixture and it was realized that maximum improvement in compressive strength happened for the concrete mix having 5% say dust plus rice husk ash by mass of cement. Slumps test was performed on the fresh concrete and compressive strength test on toughened concrete. The concrete cubes were tested at the ages of 3, 7,14,28,56 and 90 days. The results showed that sawdust ash including rice husk ash is good pozzolan with combined SiO2, A12O3 and Fe2O3 of 73.07%. The slump decreased as the sawdust ash including the rice husk ash content amplified. The compressive strength reduced with increasing sawdust ash including rice husk ash replacement. The compressive strength of concrete added with sawdust ash including rice husk ash was lesser at initial stages but improved significantly after 28 days. It was concluded 15% sawdust ash including rice husk ash substitution is satisfactory to enjoy maximum benefit of strength. This work summarized the behavior of concrete involving incomplete substitution of cement by sawdust ash including rice husk ash as 0%, 5%, 10%, 15%, 20%, and 25% by weight which may help to reduce the disposal problems of sawdust ash including rice husk ash, and also enhance properties of concrete.
1.2 AIM OF STUDY
This work is focused on the effect of Rice husk ash (RHA) plus sawdust ash (SDA) on the strength of concrete by incomplete replacement of cement.
1.3 OBJECTIVE OF STUDY
The objective of this work includes the following:
- To determine the compaction characteristics of concrete when cement is in part replaced with rice husk ash and sawdust ash.
- To investigate the strength of concrete, when cement is in part replaced with rice husk ash and sawdust ash.
- To investigate and evaluate the durability of concrete when moderate replacement of cement is carried out using sawdust ash and rice husk ash.
1.4 SCOPE OF STUDY
The use of rice husk ash including sawdust ash as in part replacement for cement in concrete can be determined by carrying out test on the coarse aggregate (granite), fine aggregate (sharp sand) rice husk ash, sawdust ash, cement and the concrete cubes. The test include
Sieve Analysis: The test is performed to ascertain the percentage difference in diverse grain particles enclosed within a soil. The mechanical or sieve analysis is performed to determine with certainty the distribution of the rougher, larger-sized elements, and the hydrometer process is used to ascertain with a level of certainty the distribution of the smoother and smaller particles.
Specific Gravity Test: This test is performed to establish the precise gravity of soil with the aid of a pycnometer. Specific gravity is the ratio of the weight per unit value of a certain volume of soil at a specified temperature to the weight per unit of the same volume of gas-free distilled water at a specified temperature.
Slump Test: This test is used to establish the workability of the concrete.
Compressive Strength Test: This is used to evaluate the strength of the concrete.
1.5 JUSTIFICATION
Grain-size analysis, which is amongst the oldest of soil tests, is used in soils classification and as part of the qualifications of soil for airstrips, infrastructures, earth dams, and other soil-realizable construction. The typical grain-size analysis test was used to establish the relative quantities of altered grain sizes as they are scattered among certain size range, which is denoted as particle-size or grain-size distribution.
This is accomplished in two steps:
• A screening process (a sieve analysis which is also called a mechanical analysis) for particle sizes retained on the No. 200 sieve.
• A sedimentation procedure (a hydrometer analysis) for element sizes smaller than the No. 200 sieve.
The specific gravity of a soil is utilized in the segmented relationship of water, air, and solids in a specified volume of the soil. Specific gravity is a test that provides us with the ratio of the weight per unit volume of soil at a specified temperature to the weight of similar volume of gas-free distilled water at a stated temperature.
Compressive strength test of concrete was performed to know if the concreting was done properly or not. It gives us the idea about all the characteristics of concrete.
Nigeria is rich in timber and production of rice. The production of cement for construction is now expensive because of the high demand for erection of structures and aggregates and sudden depreciation of the country’s economy. This had escalated the cost erection of structures and maintenance. Therefore alternative pozzolan other than cement has to be sought for to encourage engineering activities within the country. Some of the pozzolanic materials are costly while some are not easily accessible.
In carrying out this work, we hope that the rice husk ash and the sawdust ash could be useful material instead of a nuisance to the environment.
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