Performance of lightweight concrete using palm oil clinker as coarse aggregate

Abstract

Malaysia is one of the primary producers of palm oil in Asia and it is the second largest palm oil-producing country in the world. Due to a lot of waste from palm oil mill and the construction costs are rising, the alternative to recycle them should be taken. In this study, palm oil clinker (POC) aggregates were used as coarse aggregate replacement in lightweight concrete production. This study focused mainly on the physical properties of POC aggregate and the performance of fresh and hardened concrete mixture to identify the optimum content of replacement of POC as coarse aggregate in lightweight concrete to attain reasonable strength. The approach used in the mix design involved POC replacement of 0%, 33%, 67% and 100% of the content of coarse aggregates. Based on sieve analysis, the coarse aggregate was well graded. It was found that, as the percentage of replacement of POC increased, the workability of the fresh concrete and density of hardened concrete was decreased. This was due to the physical properties of POC aggregate which is porous, low specific gravity, low bulk density and high water absorption. The maximum compressive strength of the sample was 25.24 MPa at 7 days and 27.89 MPa at 28 days while splitting tensile strength and flexural strength achieved 5.12 MPa and 3.98 MPa. As obtained from experiment, the optimum content of replacement of POC as coarse aggregate to achieve lightweight concrete was about 67% since the results from mechanical properties test complied with the requirement of structural lightweight concrete as stipulated in British Standard, BS 8110 : Part 2 : 1985, RILEM’s functional classification of lightweight concrete, ASTM C330 and other previous studies. Considering POC into the lightweight concrete structure, it is possible to reduce the dead load thus saving the construction cost by reducing the size of columns, footings and other load bearing elements of a concrete structure.