ABSTRACT
In this research work, the mechanical properties, durability and stiffness parameters of concrete in which the concrete component was partially replaced with cassava peel ash (CPA) were investigated. The replacement level of cement with CPA ranges from 0 – 40% at the hydration period of 3, 7, 28, 60 and 90 days respectively. The chemical analysis of CPA shows that it contain SiO2 (55.93%), Fe2O3 (6.02%) and Al2O3 (19.93%) among other oxides. The sum total of SiO2, Fe2O3 and Al2O3 is greater than 70% minimum prescribed by ASTM C618 – 78 which indicates that CPA can be used as a pozzolan. The pozzolanic activity index (PAI) of CPA is 75.8% which is also an indication that it has very high remarkable pozzolanic properties. The results of compressive strength of 5 – 40% replacement of cement with CPA range from 12.56N/mm2 to 33.26N/mm2 as against 13.93N/mm2 to 35.23N/mm2 for the control test. The result of flexural strength of 5 – 40% replacement of cement with CPA range from 3.33N/mm2 to 15.17N/mm2 as against 4.67N/mm2 to 16.80N/mm2 for the control test (0% replacement). The initial setting time of 5% to 40% replacement of cement with CPA range from 55minutes to 123minutes as against 52minutess for the control test. The final setting time of the cement with CPA at the same replacement level range from 596minutes to 788minutes as against 591minutes for the control test. The young’s modulus of elasticity for 5% to 40% replacement of cement with CPA range from 22572.09 N/mm2 to 31124.51 N/mm2 as against 23352.50 N/mm2 to 31721.31 KN/m2 for the control test. The modulus of rigidity of 9405.038 N/mm2 to 12968.55 N/mm2 as against 9730.208N/mm2 to 13217.21 N/mm2 for the control test.
TABLE OF CONTENTS
Title Page i
Declaration ii
Dedication iii
Certification iv
Acknowledgement v
Table of Content vi
List of Tables x
List of Figures xi
Abstract xii
CHAPTER ONE
1. INTRODUCTION 1
1.1 Aim and Objectives of the Project 3
1.2 Statement of Problem 4
1.3 Justification 4
1.4 The Research Scope 5
CHAPTER TWO
2. LITERATURE REVIEW 6
2.1 Cement 7
2.1.1 Cement Hydration Reaction 8
2.2 Cement Composition 8
2.3 Production of Cement Hydration 10
2.3.1 Calcium Silicate Hydrate 11
2.3.2 Calcium Hydrate 11
2.3.3 Calcium Sulfoaluminate Hydrates 11
2.3.4 Un-Hydrated Clinker Grains 11
2.4 Pozzolan 12
2.5 Concrete Aggregates 13
2.6 Various Ashes used as Pozzolans 15
2.6.1 Cassava Peel Ash (CPA) 15
2.6.2 Bagasse Ash 15
2.6.2.1 Properties of Bagasse-ash 16
2.6.3 Rice-Husk Ash (RHA) 16
2.7 Effects of Pozzolanic-reaction in Production of Concrete 17
2.7.1 Mineralogical Effect of the Pozzolanic-Reaction 17
2.7.2 Calcination Effect 18
2.7.3 Pozzolan Composition 19
2.7.3.1 Reaction Conditions 20
2.7.4 Factors that Affect Pozzolanic-Activity 20
2.7.5 Pozzolanic-Activity Tests 20
2.7.5.1 Mechanical tests 20
2.7.5.2 Chemical tests 21
2.7.6 Artificial Pozzolanas 21
CHAPTER THREE
3. MATERIALS AND METHODS 23
3.1 Experimental Program 23
3.2 Materials 23
3.2.1 Cement 23
3.2.2 Cassava Peel Ash(CPA) 24
3.2.3 Water 24
3.2.4 Aggregates 24
3.2.4.1 Fine Aggregate 24
3.2.4.2 Coarse Aggregate 24
3.3 METHOD
3.3.1 Compressive strength 24
3.3.2 Flexural strength 26
3.3.3 Setting time 26
3.3.4 Sieve Analysis 27
3.3.4.1 Procedure of Grain Size Analysis of Aggregates 27
3.3.4.2 Calculations of Grain Size Analysis 28
3.3.4.3 Graph of sieve analysis 28
3.3.5 Slump Test 28
3.3.5.1 Factors affecting the workability of concrete 28
3.3.6 Fineness Modulus 30
3.3.6 Modulus of Elasticity of Concrete 30
3.3.8 Modulus of Rigidity 32
3.3.9 Durability Test 33
3.4 Determination of Total Elements in the Cassava Peel Ash samples 34
3.4.1 Loss on Ignition 35
3.5 Data Processing 36
3.5.1 Hypothesis Testing 36
3.5.2 Correlation Coefficient 37
3.6 Pozzolanic Activity Index (PAI) 38
3.6.1 Test Mixture Proportion 38
CHAPTER FOUR
4. RESULTS AND DISCUSSION 40
4.1 Physical Properties of Constituent’s Aggregates 40
4.1.1 Fineness Modulus (FM) 40
4.2 Chemical Composition of Cement and Cassava Peel Ash 41
4.3 Workability Test Result (Slump) 43
4.4 Setting T Result 44
4.5 Mechanical Properties of the concrete 45
4.5.1 Compressive Strength Results of the Concrete 45
4.5.2 Flexural Strength Results of Concrete 48
4.5.3 Modulus of Elasticity and Rigidity of the Concrete 51
4.5.4 Durability Test Results 53
4.5.5 Pozzolanic Activity Index 57
4.6 Statistical Analysis and Validation of Results 58
4.6.1 Correlation Analysis Results 58
CHAPTER FIVE
5. CONCLUSION AND RECOMMENDATION 60
Conclusion
Recommendations
Reference 62
APPENDICES
LIST OF TABLES
Table 1.The Approximate Oxide Composition Limits of Ordinary Portland Cement 9
Table 2.Major Compounds of Cement (Bogue, 1947) 9
Table 3. Natural Pozzolans and their Essential Active Ingredient with Activity Type 19
Table 4. Mix Proportions for the concrete work 39
Table 5. Fineness Modulus of the Test Aggregates 41
Table 6. Chemical Composition of the Test Samples 42
Table 7. Chemical Analysis of Dangote Cement 42
Table 8. Slump Test Results 43
Table 9. Setting time results of the Mixture samples 44
Table 10. Compressive Strength of Cassava Peel Ash Concrete 46
Table 11.Flexural Strength of Cassava Peel Ash Concrete 49
Table 12. Modulus of Elasticity and Rigidity of Concrete 51
Table 13. Durability Tests Result in Terms of Compressive Test of CPA Concrete 54
Table 14. Durability Tests Result in Terms of Flexural Test of CPA Concrete 55
Table 15.Parameters for the Correlation Analysis 58
Table 16. Correlation analysis results 58
LIST OF FIGURES
Fig. 1. Particle Size Distribution of Test Aggregates 40
Fig 2. Setting time versus % replacement of CPA 45
Fig. 3. Graph of compressive strength versus concrete curing age 48
Fig. 4. Graph of Flexural strength versus concrete curing age 51
Fig. 5. Graph of Modulus of elasticity versus curing age of concrete 52
Fig. 6. Graph of Modulus of rigidity versus curing age of concrete 53
CHAPTER ONE
1. Introduction
Structural works construction materials account for about 40% – 60% of the cumulative cost of executing the construction-project which is because of exponential rise in the basic conventional materials’ cost such as aggregates and cement (Shafigh et al., 2014). The cost increase of these conventional construction-materials is because of high cost expended in their production, processing and haulage. Apart from the economical aspect, hydration-reaction of cement has resulted to a buildup of CO2 emissions in the atmosphere which consequently leads to global-warming and endanger our environment. To tackle this challenge, utilization of supplementary-cementitous-materials to substitute cement in-order to decrease the total construction-cost and also achieve environment efficient, environment friendly, and sustainable growth in terms of infrastructure (Lothenbach et al., 2011). Cassava-peel is a waste (by-product) from cassava-processing and these materials are generated either on domestic level (household) or industrial level. The cassava-peel consists of twenty to thirty-five percent of the total tuber weight especially by hand peeling (Salau et al., 2011).
The advantage of saving construction-materials cost and also to mitigate environmental degradation challenges due to poor/unhygienic disposal of various agricultural/industrial wastes and also oxides of carbon emission from both industrial plants and cement-hydration as-well-as the enhancement of concrete durability performance, has led to increasing research into the utilization and re-cycling of several wastes and its derivatives which possesses alumino-silicate content (Mikulčić et al., 2016). Poor waste management system provides a breeding terrain for vectors of various diseases and also contributes to climate change on global level through the production of methane (Nagendran, 2011). Pozzolans are considered to contain silica and alumina which in divided finely state and in moisture presence reacts with calcium-hydroxide to generate cementitious compounds such as calcium silicates hydrates, calcium sulfo-aluminate hydrates and calcium-aluminate hydrates (Snellings et al., 2012). Pozzolanic material utilization as a building construction material is nearly as old as ancient civilization where these alumino-silicate materials are used to better the lime’s characteristics; many of these structural works are still intact as a confirmation of the durability property of pozzolanic-lime mortars (Olusola et al., 2019).
In this study, the CPA was utilized as supplementary-cementitious -material (SCM) to substitute cement in concrete partially at varying ratios from 0 % to 50 % in terms of workability, setting time, flexural-strength, modulus-of-rigidity and elasticity, durability performance, compressive-strength and pozzolanic-activity index.
Concrete is one of the most common construction materials as a result of its durability property and requiring very small or no concrete maintenance. Concrete structures are usually situated in highly polluted industrialized and urban areas, severe marine salty environments where some other construction materials were observed to be non-durable. The use of wastes and its derivatives which possesses alumino-silicates content with pozzolanic property in concrete production helps to enhance its durability property; as the concrete is situated at these environmental severe conditions. The need to obtain more sustainable cementing products in concrete makes it essential for researchers to indulge in the pozzolanic-activity assessment of supplementary-cementitous-material so as to obtain the safe combination level of these additives in concrete (Massazza, 2001).
The physicochemical and mechanical characteristics of pozzolans are derived from their behavior when situated or placed in a very aggressive environment. The pozzolans composed primarily of aluminic content are majorly chloride resistant while the silicic pozzolans serve well as sulphate resistant (Hewayde et al., 2007). The pozzolanic-activity measures the reaction-rate of calcium-hydroxide or Ca2+ and pozzolan in moisture presence. The intrinsic-properties of the pozzolans namely; the active-phase content, the surface-area and the chemical-composition affects the pozzolanic-reaction rate while the physical surface-adsorption is not considered because no molecular irreversible bond are obtained in the process. The pozzolanic-reaction rate can be also affected by external agents like available quantity of water, mix proportion, hydration product growth and reaction temperature (Benezet et al., 1999). Pozzolanic-activity assessment of SCM is essential due to the need for more cementitious sustainable products. For the Pozzolanic-activity assessment with cement, ASTM standard C618-78 prescribed standard-specification for pozzolanic-activity-index evaluation. This is developed by the determination of mixtures’ strength with a prescribed substitution ratio of cement by pozzolan.
1.1 Aim and Objectives of Study
This research study aims the experimental assessment, characterization and utilization of cassava-peel-ash (CPA) to replace cement in concrete-mix
The research work’s specific objectives are outlined as follows:
i. Characterization of CPA as additives for concrete and mortar production using pozzolanic activity index.
ii. To obtain the optimum combination of CPA in a given concrete or mortal mixture using inferential statistical method.
iii. Determination of physicochemical characteristics and CPA – cement paste setting time.
iv. Mechanical properties evaluation of the CPA concrete in respect to compressive-strength, flexural-strength, durability performance, modulus-of-rigidity and elasticity for varying hydration-periods from 3 to 90days.
v. To compare the concrete’s properties produced with without the additive (control) and those containing the optimum combination of the CPA.
1.2 Statement of the Problem
Production of concrete is becoming a very expensive venture because the major conventional ingredients namely; water, cement, coarse and fine-aggregates are very expensive especially cement which is the costliest and the emission of carbon-dioxide to the atmosphere which contribute to global-warming. Research has been ongoing in-order to discover viable options to cement in concrete production. This could be achieved by replacing cement partially in the cementitous content by alumino-silicate content and are pozzolanic in nature. These materials are obtained from solid wastes in ash or powdered form. By addition of this materials, the cement’s quantity used in the concrete works will be reduced thereby minimizing the production cost, environmental challenges due to emission of CO2and also in the area of waste-management by re-use of industrial/solid waste is enhanced.
1.3 Justification
The research work’s results will yield the following advantages:
i. Minimize the construction-cost and acquisition of very good housing accommodation.
ii. Helps in the recycling and re-use of solid-waste derivatives and eco-friendly process of obtaining these derivatives for engineering applications.
iii. It will result in conservation of energy and savings of natural resources.
iv. It has rural applicability.
1.4 The Research Scope
The project-scope is listed as follows:
i. To review the existing literature on the related topics.
ii. The experiments which will help to achieve characterization of cassava-peel waste material in-order to obtain the material’s physicochemical properties.
iii. To carry out experimental study on CPA –concrete mortar both in hardened and fresh states in-order to obtain the mechanical strength behavior of the material through casting concrete cubes and beams using the CPA in various proportions to replace cement.
iv. To test the performance of the CPA concrete as regards to durability characteristics. This is achieved by immersion of the hardened material into concentrated solution of sodium-hydroxide (base) and Sulphuric acid while monitoring the rate and extent of deterioration.
v. Analysis and data results discussions using pozzolanic-activity index and statistical method.
vi. Conclusions and recommendations.
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