Assessment of Manufactured Sand in Concrete Produced with Palm Kernel Shells as Coarse Aggregate

This article reports on a research carried out to assess the effects of manufactured sand in concrete, produced with palm kernel shells as coarse aggregate; on the strength, weight in air and workability. The concrete was designed using British Building Research (BRE) method, and a total of 54 cubes were made of 150mm by 150mm by 150mm. Two concrete classes were designed and produced, namely Lightweight Concrete (LC) class 22 and 38, then cured for 28 and 90 days. The specified design slump was between 30mm-60mm. Natural sand was replaced by manufactured sand (Msand) at 25% intervals, batched by volume till it got to 100% fine aggregate usage. The coarse aggregate portion was solely PKS, batched by volume. The maximum compressive strength for LC 22 was 16.1N/mm2 and 18.22 N/mm2, at 28 and 90 days respectively. While LC 38 was 19N/mm2 and 20.3N/mm2, in same order. Msand replacement portion applicable to both LC22 and LC38 was 32%. Compressive strength gained with time by samples, were not directly proportional to the densities developed with respect to time. The strength differences were 26.8% and 48.7% for LC22 and LC38 respectively, when compared with the expected characteristic strengths.