Physico-mechanical and thermal performances of eco-friendly fired clay bricks incorporating palm oil fuel ash

Abstract

This study investigated the use of palm oil fuel ash (POFA), a by-product of burning solid waste from palm oil production, as a clay replacement in brick manufacturing. Clay was thus replaced with 5%, 10%, 15%, and 20% POFA by weight in bricks produced in a local factory to study the feasibility of large-scale manufacturing. The physico-mechanical properties of these bricks (linear shrinkage, weight per unit area, compressive strength, and apparent porosity) were compared with those of conventional bricks without POFA. The thermal performances of the bricks were assessed by measuring the difference in temperature between their top and bottom surfaces during exposure to direct sunlight. The results of this study indicate that replacing clay with POFA reduced the linear shrinkage of the bricks. Furthermore, the weight per unit area and compressive strength of bricks containing higher replacement percentages of POFA decreased due to their increasingly porous structure. Replacing clay with up 10% POFA still met the minimum compressive strength criteria of the Indonesian Industrial Standard for non-load-bearing wall materials (i.e., 2.5 N/mm2). Furthermore, 10% POFA bricks provided better thermal performance, exhibiting a temperature difference of about 6 °C compared to 2.5 °C for conventional bricks without POFA. Therefore, using 10% POFA as a clay replacement in large-scale brick production can address POFA disposal problems, reduce clay consumption, and decrease energy demand for indoor cooling, yielding a more environmentally friendly clay brick.