EFFECT OF PALM KERNEL SHELLS AND RICE HUSK ASH ON THE PHYSICAL AND MECHANICAL PROPERTIES OF NORMAL WEIGHT CONCRETE

Abstract

Concrete is the most used construction material in the world and also the second most consumed substance in the world after water. Concrete flexibility and increase in population has resulted in the high use of the material for the construction of shelters, infrastructures, and work places among other, thereby contributing to the high cost of the material. There is a worry in the construction industry about the depletion of natural resources from which concrete is produced in the near future. This high demand for concrete has also increased the price of the material making it almost impossible for low income earners to own houses and leaving many homeless. Also, increased in population has increased agricultural activities across the globe in order to tackle the problem of food insecurity amongst which include rice and palm farming. The negative effect of these increased agricultural activities is the high environmental pollution as wastes from these activities are openly burned in many instances as a mean of disposal, releasing a significant amount of carbon dioxide (CO2) in the atmosphere. These concerns have prompted research towards waste materials that could be used as alternatives to those conventional materials for concrete production while at the same time minimizing the high environmental pollution. Through these efforts, it was discovered that Palm Kernel Shell (PKS), the by-product of palm farming, can partially replace coarse aggregate to produce structural concrete. Similarly, it was discovered that Rice Husk Ash (RHA), a waste from the rice farming, can be used as a pozzolana to replace portion of the cement in concrete production. However, limited information was found on the combine effect of PKS and RHA as partial replacements for coarse aggregate and Portland cement respectively on normal concrete. It was the aim of this research to investigate the effect of PKS and RHA on normal weight concrete (NWC) as partial replacements for coarse aggregate and ordinary Portland cement (OPC) respectively. Effects were determined in terms of concrete workability, density, water absorption, compressive strength, and splitting tensile strength. Twelve mixes were designed in which PKS was varied at 0, 25, and 50% and RHA at 0, 10, 15, and 20% in a mix ratio of 1:2:3 for cement, fine aggregate, and coarse aggregate respectively with a constant free water to cement ratio of 0.58. Batching was by volume and a total of 108 cubes and 72 cylinders were casted. Specimens were cured for 7 and 28 days. It was found out that PKS and RHA use in concrete reduce workability, density, compressive strength and splitting tensile strength and increase water absorption at 28 days of curing. However, the resulting concrete was satisfactory for structural used.