A critical review of various types of palm oil fuel ash (POFA) utilization in enhancing concrete and mortar properties
Abu Sufian, Md. Rezaur Rahman, Khairul Anwar Bin Mohamad Said, Muhammad Khusairy Bin Bakri
Abstract
Palm oil fuel ash (POFA) is a type of palm oil waste that has a high composition of silicon dioxide (approximately 56%), which garners the focus of this critical review on its potential as a sustainable supplementary cementitious material (SCM). This review highlighted the benefits of grinding and heat treatment process to an untreated POFA that has enhanced both the chemical and physical characteristics of POFA through the reduction of carbon content, altering its color from dark grey to reddish grey, and directly improved its pozzolanic reactivity. Besides that, an ultrafine POFA with its finer particle size and greater surface area has been shown to increase compressive strength by facilitating accelerated cement hydration via a theory of nucleation and growth, and promoting pozzolanic reactions, contributing to enhanced ultimate strength development. The role of ultrafine POFA in cement hydration and its pozzolanic mechanism is also highlighted in the review. The overall quality of concrete is improved by integrating ultrafine POFA, as evidenced by increased durability, reduced drying shrinkage, and higher ultrasonic pulse velocity (UPV). Despite these promising outcomes, further investigation is warranted regarding the drying shrinkage, UPV, and mechanical properties such as flexural strength and elasticity of POFA-blended cement concrete. Additionally, future research should explore the performance of POFA-blended concrete under various temperatures and environments, as well as the incorporation of supplementary materials, such as fly ash, eggshell, and limestone powder which can further improve the properties of POFA in concrete applications. The environmental and economic benefits of utilizing POFA as an SCM, particularly its role in mitigating the carbon footprint associated with cement production, are also highlighted. While POFA demonstrates considerable promise as a sustainable building material, continued research is essential to fully realize its potential.