Evaluation Of Mechanical Properties Of Palm Oil Fuel Ash (Pofa) Blended – Granite – Gravel Concrete
The evaluation of mechanical properties of concrete blends incorporating Palm Oil Fuel Ash (POFA), granite, and gravel is crucial for assessing their structural integrity and suitability for various construction applications. POFA, a waste material from the palm oil industry, is increasingly utilized as a supplementary cementitious material due to its pozzolanic characteristics, contributing to enhanced durability and strength in concrete mixtures. The addition of POFA to concrete blends, alongside traditional aggregates like granite and gravel, facilitates improvements in compressive strength, flexural strength, and durability while potentially reducing the carbon footprint of concrete production. Through comprehensive testing methodologies such as compressive strength tests, flexural strength tests, and durability assessments including water absorption and resistance to chloride ion penetration, the performance of POFA-blended concrete in comparison to conventional concrete mixtures can be thoroughly analyzed. This research contributes valuable insights into sustainable construction practices, resource optimization, and the development of high-performance concrete blends suitable for diverse engineering applications, ultimately advancing the utilization of alternative materials in the construction industry.
Utilizing Palm Oil Fuel Ash (POFA) in concrete mix is a major way of turning waste to wealth. Gravel as an aggregate is cheaper than granite. Thus, obtaining an optimum combination of these materials in achieving a maximum compressive strength in concrete will go a long way in helping the construction industry.The study was carried out to establish an optimum replacement ratio for Palm Oil Fuel Ash (POFA) blended granite-gravel of concrete. Uniform water/binder (w/b) ratio of 0.5 and mixes ratio of 1:2:4 was utilized. Thirteen runs of experiments plus control were designed using the Central Composite Response Surface method (Design Expert). Based on the analysis, the increase in granite volume led to increase in compressive strength. However, increase in POFA percentage led to decrease in compressive strength at 7, 28, 56 and 90 days curing ages. The study also observed highest compressive strength at 25% POFA replacement and lowest at 35% replacement. Also, for granite, highest and lowest compressive strength were achieved at 100% and 0% replacement respectively. However, for slump height, the higher the percentage of granite or POFA in concrete, the higher the slump height. The optimization analysis showed that, at 29.69% POFA and 98.75% Granite, compressive strength of 24.29 N/mm2 and slump height of 89.36mm were achieved. The optimum strength found is slightly higher than the maximum strength achieved (24.27N/mm2) at 90 days and also, slightly lower than the control (25.33 N/mm2).
CERTIFICATION
DEDICATION
ACKNOWLEDGEMENT
LIST OF TABLES
LIST OF FIGURES
ABSTRACT
CHAPTER ONE 1
INTRODUCTION 1
1.1 Background of the study 1
1.2 Scope 4
1.4 Justification 5
1.5 Statement of Problem 5
1.6 Aim 5
1.7 Objectives 5
CHAPTER TWO 6
LITERATURE REVIEW 6
2.1 Properties of concrete with POFA 6
2.1.1 Physical properties 6
2.1.2 Chemical Properties of POFA 7
2.1.3 Mechanical properties of POFA 8
2.2 Compressive Strength of Concrete with Replaced POFA 10
2.3 Ultrasonic Pulse Velocity (UPV) of Concrete with Replaced POFA 13
2.4 Workability of Concrete with Replaced POFA 14
2.5 Porosity of Concrete with Replaced POFA 16
2.6 Permeability of Concrete with Replaced POFA 18
2.7 Properties of Cement 19
2.7.1 Physical properties of Cement 19
2.7.2Mechanical properties of Cement 20
2.7.3Chemical Properties of Cement 20
2.7.4Cement hydration 20
CHAPTER THREE 22
Study Area 22
3.0 Materials Used and Methodology 22
3.1. Materials 22
3.1.1 Cement 23
3.1.2 Aggregate 23
3.1.3 Granite 23
3.1.4 Gravel 23
3.1.5 Water 24
3.1.6 Palm Oil Fuel Ash (POFA) 24
3.2 Methodology 25
3.2.1. Sieve Analysis Procedure 25
3.2.2 Specific Gravity of Ordinary Portland Cement Determination 26
3.2.2.1 Experimental Procedure 27
3.3: Concrete Mix Design 29
3.4 Fresh Concrete Workability 30
3.5 Density 31
3.6 Determination of Compressive Strength 31
CHAPTER FOUR 33
RESULTS AND DISCUSSIONS 33
4.1 Oxides Composition of POFA 33
4.2 Grain size distributions from sieve analysis 34
4.3 Compressive Strength Test Results 35
4.4 Optimum Mix Ratio Determination 52
CHAPTER FIVE 53
CONCLUSION AND RECOMMENDATIONS 53
5.1 Conclusion 53
5.2 Recommendation 54
REFERENCES 55
INTRODUCTION
1.1 Background of the study
Concrete is regarded as the primary and widely used construction ingredient around the world in which cement is the key material. However, large scale cement production contributes greenhouse gases both directly through the production of CO2 during manufacturing and also through the consumption of energy (combustion of fossil fuels). Moved by the economic and ecological concerns of cement, researchers have focused on finding a substitution of cement over the last several years. In order to address both the concerns simultaneously many attempts have been made in the past to use materials available as by product or waste. This is due to the fact that the use of by product not only eliminates the additional production cost, but also results in safety to the environment. Hence, the development and use of blended cement is growing rapidly in the construction industry mainly due to considerations of cost saving, energy saving, environmental protection and conservation of resources.
A number of investigations have been carried out with Palm oil fuel ash (POFA), an agro-waste ash, as potential replacement of cement in concrete. Sata et al. (2004) found compressive strength of 81.3, 85.9, and 79.8 MPa at the age of 28 days by using improved POFA with a reduced particle size of about 10 microns in concrete as replacement of 10%, 20% and 30% of cement respectively. They also reported highest strength at 20% replacement level. Tangchirapat [2009] observed the compressive strengths of ground POFA concrete in the range of 59.5–64.3 MPa at 28 days of water curing and with 20% replacement it was as high as 70 MPa at the end of 90 days of water curing. However, the drying shrinkage and water permeability were noted to be lower than that of control concrete with improved sulphate resistance. Past researchers also depict that both ground and un-ground POFA increase the water demand and thus decrease the workability of concrete. However, ground POFA has shown a good potential for improving the hardened properties and durability of concrete due to its satisfactory micro-filling ability and pozzolanic activity. Palm Oil Fuel Ash (POFA) is known as the by-product form from the incinerationof the palm oil fibers, shells, and empty fruit bunches in the biomass thermal power plant to generate energy. However, it was found that 5 % of the residue was then produced as the result of combustion and the wastes are then managed by disposing as landfill materials which lead to environmental hazards eventually. As stated by Aprianti et al. (2015), POFA is tagged as the environmental disruption pollutant which ends up in the atmosphere without being utilized in 20th and 21stcentury, if compared to other types of palm oil by-products.
Over the past several decades, attempt has been made to use several waste and by product material produced by the industries as potential partial replacement of cement in concrete. Investigations have been carried out through replacing part cement with industrial and other wastes such as Silica fume, ground granulated blast furnace slag, bagasse ash, rice husk ash, palm oil fuel ash, Paper mill ash, Wheat straw ash, Wallostonite, Metakaolin and many more (Karim et al., 2014). The use of these materials in concrete has significant benefits from environmental and economic stand point in comparison to traditional cement. In order to promote the utilization of POFA, many researchers established the researches regarding the POFA as the Supplementary Cementitious (SCM) in either concrete or mortar. The properties and performances of the finished products were examined and the researchers commented that the utilization of the POFA as a supplementary materials of cement is suitable. This is because the ash can increase the engineering and durability properties of either concrete or mortar. Karim et al., (2011) discovered that concrete produced using a particular level of POFA replacement achieved same or more strength as compared to OPC concrete. No significant strength reduction of concrete was observed up to about 30% replacement of POFA. Safiuddin et al., (2012) observed that the use of POFA is limited to a partial replacement, ranging from 0-30% by weight of the total cementitious material in the production of concrete. Indeed, the partial replacement has a beneficial effect on the general properties of concrete as well as cost. Sata et al., (2010) investigated that the strength development of POFA concretes with w/c ratios of 0.50, 0.55, and 0.60 tended to be in the same direction. At early ages, concretes containing POFA as a cement replacement of 10, 20, and 30% had lower strength development than control concretes while at later age 28 days, the replacement at rates of 10 and 20% yielded higher strength development. Mohammed Hussin and Awal., (2009) studied concrete replaced with POFA with a water to binder ratio of 0.45, were seen to develop strength exceeding the design strength of almost 60MPa at 28-day. Hussin et al., (2009) discovered that inclusion of 20% POFA would produce concrete having highest strength as compared to any other replacement level. Ahmad et al., (2008) studied that one of the potential recycles material from palm oil industry is palm oil fuel ash which contains siliceous compositions and reacted as pozzolans to produce a stronger and denser concrete. Pozzolanic material has little or no cementing properties. However, when it has a fine particle size, in the presence of moisture it can react with calcium hydroxide at ordinary temperatures to provide the cementing property. Ahmad et al., (2008) reported that the chemical composition of POFA contains a large amount of silica and has high potential to be used as a cement replacement. Hussin et al., (2009) have found that POFA can be used in the construction industry, specifically as a supplementary cementitious material in concrete. Hussin et al., (2009) studied the compressive strength of concrete containing POFA. The results revealed that it was possible to replace at a level of 40% POFA without affecting compressive strength. The maximum compressive strength gain occurred at a replacement level of 30% by weight of binder. Karim et al., (2011) investigated that replacing 10–50% ash by weight of cementitious material in blended cement had no significant effect on segregation, shrinkage, water absorption, density, or soundness of concrete.
1.2 Scope
Ordinary Portland Cement (OPC) concrete i.e. concrete with 100% OPC and ordinary gravel as control, and concrete with 25% – 35% POFA replacement and granite-gravel of 0% – 100% replacement having uniform water/binder (w/b) ratios of 0.5 and mixes ratio of 1:2:4 were used. Curing ages of 7 days, 28 days, 56 days and 90 days were considered.
1.4 Justification
Utilizing Palm Oil Fuel Ash (POFA) in concrete mix is a major way of turning waste to wealth. Gravel as an aggregate is cheaper than granite. Thus, obtaining an optimum combination of these materials in achieving a maximum compressive strength in concrete will go a long way in helping the construction industry.
1.5 Statement of Problem
Large scale cement production contributes to greenhouse gases both directly through the production of CO2 during manufacturing and also through the consumption of energy. Therefore, this study examines the suitability of Palm Oil Fuel Ash (POFA) replacement with cement as Supplementary Cementing Materials. One of the potential recycle materials from palm oil industry is palm oil fuel ash which contains siliceous compositions and reacted as pozzolans to produce a stronger and denser concrete
1.6 Aim
To determine the mechanical properties of Palm Oil Fuel Ash (POFA). To address the aim, the following objectives were identified:
1.7 Objectives
1. To determine concrete compressive strength of granite-gravel concrete at varying replacement of Palm Oil Fuel Ash (POFA) at different curing ages.
2. To establish an optimum replacement of Palm Oil Fuel Ash (POFA) in granite-gravel blended.
Palm Oil Fuel Ash (POFA) is a waste material obtained from the combustion of palm oil husk and palm oil shell in palm oil mills. When used as a supplementary cementitious material in concrete, it can influence the mechanical properties of the resulting concrete mix. Here are some of the mechanical properties of Palm Oil Fuel Ash-blended granite-gravel concrete:
- Compressive Strength:
- The compressive strength of concrete is a critical mechanical property. The addition of Palm Oil Fuel Ash to concrete can have both positive and negative effects on compressive strength, depending on factors like the percentage of Palm Oil Fuel Ash used, curing conditions, and the quality of the Palm Oil Fuel Ash. In some cases, Palm Oil Fuel Ash can enhance the compressive strength of concrete when used as a partial replacement for cement.
- Tensile Strength:
- Tensile strength is generally lower in concrete compared to compressive strength. The incorporation of Palm Oil Fuel Ash may slightly reduce the tensile strength of concrete, but it can be compensated for by using appropriate reinforcement like steel bars (rebar) in structural applications.
- Flexural Strength:
- Flexural strength measures the ability of concrete to withstand bending or bending loads. Similar to tensile strength, the flexural strength of Palm Oil Fuel Ash-blended concrete may be slightly reduced compared to conventional concrete. However, this can often be mitigated through mix design adjustments.
- Durability:
- Palm Oil Fuel Ash contains silica and alumina, which can enhance the durability of concrete by providing pozzolanic reactions. This can result in improved resistance to chemical attack, such as sulfate attack and alkali-silica reaction (ASR), and enhance the long-term performance of concrete.
- Workability:
- The workability of concrete can be affected by the addition of Palm Oil Fuel Ash. Palm Oil Fuel Ash is a fine material, and its use may require adjustments to the mix design, such as the water-to-cementitious materials ratio, to maintain the desired workability.
- Density:
- The density of Palm Oil Fuel Ash-blended concrete may vary depending on the mix proportions and the density of the Palm Oil Fuel Ash itself. Generally, concrete with Palm Oil Fuel Ash may have a slightly lower density compared to conventional concrete.
- Shrinkage:
- The addition of Palm Oil Fuel Ash can reduce the shrinkage of concrete, which can be beneficial in minimizing cracking due to drying shrinkage.
It’s important to note that the mechanical properties of Palm Oil Fuel Ash-blended concrete can vary based on the specific mix design, curing conditions, quality of materials, and the percentage of Palm Oil Fuel Ash used. Engineers and concrete technologists should conduct laboratory tests and trials to determine the optimal mix proportions for achieving the desired mechanical properties while making the most of the benefits offered by Palm Oil Fuel Ash in terms of sustainability and cost savings.