Performance of palm oil fuel ash (POFA) in peat soil stabilization

Abstract

A study on fibric peat soil at Pontian, Johor was conducted to determine its physical properties, chemical properties and engineering properties. Due to low strength of peat soil, cement stabilization was widely used to enhance the soil performance. However, abundant amount of cement was required in peat stabilization compared to other types of soil and cement production would lead to air pollution. Palm Oil Fuel Ash (POFA) as a profitless industrial by-product was recommended to substitute some of the cement as it possesses cementitious behaviour when subjecting in cement hydrating process. 300 kg/m3 of optimum binder dosage of cement (C100) used as control specimen in peat stabilization. While the partial replacement of cement dosage in four others mixing proportions were replaced with 5 %, 10 %, 15 %, and 20 % of POFA. Scanning Electron Microscope Test (SEM) and Energy Dispersion Spectroscopy X-Ray (EDX) were applied to observe the changes in chemical composition and particles arrangement before and after treating using POFA. At 28 curing days, C85P15 achieved the highest value in unconfined compressive strength (UCS) test which was 107.6 kPa. In comparison to C100 and C80P20, C85P15 had lower carbon content, higher calcium content and lower silica and alumina content. Therefore, the ability of POFA to enhance the peat strength and effectively reduce the cement usage in peat stabilization is proved.