In this study, the compressive strengths and Modulus of elasticity of lightweight Concrete with oil palm shells as partial replacement of coarse aggregate was presented. The different types of mixing water were used, namely, clean water from Ahmadu Bello University Water Works, Salt water, obtained from Lagos Shore and Pond water obtained from Nagoye, Zaria. Also three mix ratios were adopted which include 1:2:4, 1:1.5:3 and 1:1:2 mix ratios. Five mixes were investigated; control, which contain granite coarse aggregate only; then four other mixes with 20%, 40%, 60% and 80% granite coarse aggregate replacement by oil palm Shell (OPS) aggregate. Fifteen samples where produced for each mix ratio, given a total of 135 concrete cube specimen for compressive strength tests and another 135 cylinder specimen for cylinder compressive strength tests and another 135 cylinder specimens for indirect tensile test for the determination of modulus of elasticity. In conclusion, after undertaking the laboratory practical‟s on the

OPS using 3 types of water for curing and varying the mix ratios to conform with class M15, M20 and M25, the effect of mix ratio and curing showed a tremendous difference but the use of OPS as a lightweight aggregate material was found to be adequate when compared with other materials being used as lightweight aggregate.

Natural resources of the world are drastically dwindling due to the increasing demand of natural aggregate for the construction industry. The frequent use of natural aggregate in some areas led to environmental degradation, and has given impetus to studies and researches for sustainable development by using different waste products in the construction industry. Lightweight aggregates from industrial waste such as fly ash, ground granulated blast furnace slag, bed ash has led to sustainable materials but due to the lack of production techniques, many of the developed and under-developed countries have not been able to use them to their advantage. If the weight of the structure is decreased by using lightweight aggregate in concrete, it will in turn reduce the foundation cost due to reduction in self-weight, which has been convincingly proved in developed countries (Alengaram, 2013). Reddy et al., (2014) stated that the consumption of the primary aggregate was 110 million tonnes in the U.K. during 1960 and reached nearly 275 million tonnes in the year 2006. Similarly 2 billion tones of aggregate are produced each year in the United states and it is expected to increase to more than 2.5 billion tonnes by the year 2020 (Reddy et al., 2014). It has been predicted that the demand for concrete is expected to grow to approximately 18 billion tons a year by 2050. Such heavy demands draw attention and preservation of natural aggregates, which are a matter of grave concern. Since aggregates contribute about 60–80% of the volume of the concrete, effective and efficient use of agricultural waste contributes to energy saving, conservation of natural resources and reduction of the cost of construction materials.