Effect of low inclusion of palm oil fuel ash (POFA) as a partially sand replacement to the performance of mortar

Natural sand is a major ingredient in the production of concrete and mortar. Increased urbanization and industry have led to sand depletion and the accumulation of industrial waste. Palm Oil Fuel Ash (POFA) is constantly dumped to open fields, which creates traffic dangers, health risks, and pollutes the environment. Hence, the abundance production of POFA can be used as an alternative construction material, partially replacing POFA in producing mortar and concrete to minimize dependency on the sand, avoid negative environmental impacts, and reduce construction costs. The use of POFA in mortar has been found to be limited. Therefore, this paper presents the performance of POFA used as a partially replacement of sand. The performance of mortar mixture containing 0%, 2.5%, 5%, 7.5%, and 10% of POFA inclusion by weight of sand was analyzed in terms of workability and mechanical properties. Slump tests were conducted for workability, while compressive, tensile, and flexural strength tests were conducted on hardened mortar cubes at 3,7, and 28 days to determine the mechanical properties. Workability of mortar mixture containing 2.5% of POFA inclusion was 40 mm, which recorded as the highest workability compared to other mixtures. Meanwhile, the mortar compressive strength of 2.5% POFA increased the strength to 37.7 MPa at its matured age of curing which exceeds the targeted strength of 30 MPa. The finding also shows that the inclusion of 10% POFA contributes to the enhancement of splitting tensile and flexural strength of mortar. From the result, POFA has been discovered to be an effective pozzolanic material that may be utilized as a replacement material in mortar.