Effect of palm oil fuel ash (POFA) and cockle shell on the concrete strength and durability

In this study, the effectiveness of agro waste by-product namely palm oil fuel ash (POFA) and cockle shell was evaluated as an alternative materials to partially replace the ordinary portland cement (OPC). Pozzolanic based concrete is a concrete produced by integrating POFA and cockle shell as a pozzolan. The pozzolanic materials were added in cement mixing by certain ratios POFA/cockle shell (40/0, 30/10, 20/20, 10/30, 0/40) by weight of cement binders. The compressive strength of the pozzolanic concrete due to 7 days of curing was investigated. In addition, the durability resistance of pozzolanic concrete towards hydrochloric acid solution was also assessed. The results revealed that the compressive strength of pozzolanic concretes was higher than the concrete prepared without pozzolanic materials. Thus, the addition of 30% POFA and 10% cockle shell recorded the highest strength compared to other samples. The durability test, after being immersed in acid solution for 7 days showed that pozzolanic concrete with 30% of POFA and 10% cockle shell had little weight loss compared to other ratios. It revealed that POFA and cockle shell are an excellent pozzolanic materials and can be used as an alternative cement replacement in concrete. It is recommended that the optimum replacement levels of cement by POFA and cockle shell are 30% and 10% respectively.