The incorporation of oil palm ash in concrete as a means of recycling: A review

A number of studies have used oil palm ash (OPA) as a pozzolanic material in concrete, mortar and cement pastes either as a binder or filler replacement to reduce its environmental negative impact. A coarser particle size OPA is a weak pozzolanic material; therefore, a 10% cement replacement in concrete would not affect its compressive strength. When OPA fineness is increased, concrete samples having a 20% cement replacement of fine OPA produced stronger and more resistant to sulphate attack samples than the control mix. Fine OPA samples used in these studies also showed less drying shrinkage and were less permeable to water than the 100% cement concrete mix. Mortar samples containing 20% cement replacement of fine OPA exhibited higher strength and less carbonation ingress depth than the control mortar. High strength concrete samples with a 60% cement replacement of OPA exhibited superior mechanical and transport properties than the control samples.