Effect of Pit Sand on Compressive Strength of Coconut Shell Concrete

Abstract

The high and rising cost of building materials is one of the major factors affecting housing delivery in Nigeria. Therefore, there is the need to reduce the cost of building construction either through effective construction management or usage of alternative available local materials. Concrete is one of the most important building materials in Nigeria presently, however, one of its major disadvantage, is its high selfweight

compared to other construction materials. Hence research focused towards producing a lightweight concrete from locally available material, which will reduce the total self-weight of the structure, with

corresponding reduction in cost is of national interest. This work investigated the effect of pit sand on the

mechanical

properties of concrete produced using coconuts hells as a replacement for coarse aggregate. Two batches of concrete mix were produced using coconuts hells as aggregate, with mix ratios 1:2:4. One of the batches was produced using unwashed sand from borrowed pit, while the second batch was produced using washed sand respectively. From each batch of concrete mix, 20 concrete cubes of size 150 mm x 150 mm x 150mm were produced and cured by immersion in water in curing tanks. Cubes produced using unwashed sand were named specimen A, while that produced from washed sand were named specimen B. The research shows that there is increase in the compressive strength of concrete produced from washed sand over that produced using unwashed sand. Also, concrete produced by 25% partial replacement of crushed granite by coconut shell using unwashed sand and 25% to 75% partial replacement for washed sand, can be used for structural purposes.