Palm Kernel Shell as Partial Replacement for Normal Weight Aggregate in Concrete

Palm Kernel Shells (PKS) are fractions of shells that result from the cracking of the nut to remove the seed for the production of palm kernel oil. They are of irregular shapes and vary in sizes from fine aggregate to coarse aggregate. The aim of this research was to determine the effect of PKS on Normal Weight Concrete (NWC) as partial replacement of normal weight aggregate (NWA). Effects of PKS on NWC considered were in terms of workability, density, compressive strength, splitting tensile strength, and the water absorption of the concrete. Batching was by volume since PKS was characterized as a light weight material, and substitutions were made at 0%, 25%, and 50%. The mix ratio adopted was 1:2:3 for cement, fine aggregate, and coarse aggregate with a constant free water to cement ratio (w/c) of 0.58. Curing method was by immersion and effect on the mechanical properties (compressive and tensile strengths) were determined at 7 and 28 days of curing. It was observed that the compressive, tensile strength, workability, and concrete density reduce as PKS content is increased in the mix. On the other hand, water absorption increases with increased in PKS content. However, results were in acceptable range for normal concrete. Keywords: Palm kernel shells, normal weight concrete, normal weight aggregat