Evaluation of Oil Palm Shell as Coarse Aggregate Replacement for Lightweight Concrete

Abstract

In Malaysia, oil palm shells (OPS) and agricultural waste produced by the palm oil industry are available in large quantities. Large amounts of OPS waste are undoubtedly a major disposal problem, but they also waste many resources. This study was conducted to establish the effects of OPS on workability, density, and compressive strength in concrete with a mixed design of a constant water-cement ratio. The mixes were prepared with OPS-coarse aggregate of 0%, 25%, 50% and 75% with a w/c ratio 0.5 used for all the mixes. The concrete cube size of (100 mm × 100 mm × 100 mm) was cured in water for 7 days, 21 days, and 28 days, measured for density, and tested for compressive strength. A slump test was carried out to measure the workability of fresh, wet concrete. The results showed that the concrete density decreased as the OPS replacement was increased. For 25%, 50%, and 75% of OPS replacement, the average density drop varied from 18.7% to 26.2%, 28.8% to 33.9%, and 36.1% to 37.7%, respectively. The slump value increases with the increase of the OPS percentage, indicating that the workability of the fresh concrete decreases. A true slump with high workability was identified in concrete with 25% OPS replacement. The compressive strength of concrete decreases as the percentage of OPS replacement increases. Concrete with 25% OPS replacement after 28 days of curing showed the highest strength; however, the results were below the normal compressive strength range for lightweight concrete. A few possible reasons for the unsatisfactory results and recommendations for future studies are highlighted.