Strength Properties of Sustainable Palm Oil Fuel Ash (POFA)—Stabilized Landfill

Abstract

Laboratory investigations were carried out to establish the potential utilization of palm oil fuel ash (POFA) in stabilizing landfill soil. POFA is a waste material from the palm oil industry in Malaysia. Currently, the disposal of this ash from a burning process to heat up boilers and generate electricity is a problem for palm oil companies, and hence an environmental pollution concern. Landfill on its own and in combination with laterite clay soil was stabilized using POFA either on its own or in combination with lime or Portland cement (PC). The traditional stabilizers of lime or PC were used as controls. The main aim was to investigate the potential of utilizing POFA as sustainable stabilizer material as a partial replacement of the traditional one. Compacted cylinder test specimens were made at typical stabilizer contents and moist cured for up to 60 days prior to testing for compressive and water absorption tests. The results obtained showed that landfill soil combined with laterite clay (50:50) stabilized with 20 % POFA: hydrated lime (50:50) and POFA: PC (50:50) recorded the highest values of compressive strength compared to the other compositions of stabilizers and soils. However, when the amount of POFA increased in the system the compressive strength values of the samples tended to decrease. It indicated that, high amount of POFA reduces the pozzolanic reaction and cementitious compound, which has a negative effect on soil particle bonding. These results suggest technological, economic, as well as environmental advantages of using POFA and similar industrial by-products to achieve sustainable infrastructure development with near-zero industrial waste.