Strength and Durability of Paving Block with Seawater and POFA (Palm Oil Fuel Ash)

Seawater has the potential to replace fresh water in the production of concrete. Given the restricted availability of freshwater sources and the high cost of transportation, it is crucial to optimize this scenario. On the other hand, agricultural residue is a potential material that can replace cement-based materials, thereby reducing CO2 emissions. Sustainability in the concrete sector is important, hence, research on using alternative renewable resources such as palm oil fuel ash (POFA) for concrete production is necessary. POFA is an agricultural byproduct and industrial waste that is potentially used as a partial substitution for cement due to the presence of pozzolan. The objective of this study is to examine the impact of icluding POFA (Palm Oil Fuel Ash) as a substitute in the paving block, while also considering the influence of seawater mixing and curing water. Further, POFA is used as a supplementary binder for paving blocks at 0%, 10%, 20%, 30%, 40%, and 50% for Portland Composite Cement replacement. The paving blocks properties, such as workability, density, compressive strength, water absorption, and resistance to sulfate attack, were evaluated. The results of the tests confirmed that 10% POFA mixed with seawater and cured with freshwater met the minimum necessity for Class B, as specified by the Indonesian National Standard for parking park applications. As a result of incorporating POFA as a cement replacement, a more environmentally friendly paving block could be established.