Lateritic Soil Quality Improvement Using Palm Oil Fuel Ash and Cement for Road Construction

Abstract

This research studied the possibility of using Palm Oil Fuel Ash (POFA) and Portland cement Type 1 to improve the quality of lateritic soil from the Ban Khuan Chong, Namom district, Songkhla province for road construction. The soil was improved by incorporating cement at proportions of 2%, 3%, 4%, and 5% by weight, and by incorporating a mixture of POFA with particle sizes less than 45 microns at proportions of 5%, 10%, and 15% by weight, along with 5% cement. The preliminary and engineering properties of the soil were tested, including chemical composition analysis (XRF) and microstructure analysis using a scanning electron microscope (SEM). The study found that the main components of the laterite soil improved with POFA and cement were SiO2, Al2O3, Fe2O3, CaO and K2O. The soil improved with cement achieved a maximum compressive strength of 24.8 ksc at 5% cement content over a curing period of 28 days. The soil improved with POFA and cement showed an increase in optimum moisture content (OMC) from 9.7% to 11.2%, resulting in a decrease in maximum dry density (MDD) from 1.970 to 1.861 g/cm3. The soil also achieved the maximum compressive strength of 31.1 ksc at a 5% cement mixed with 5% POFA over a curing period of 28 days. The compressive strength decreased with an increase in the amount of POFA. The soil samples improved with cement at all proportions and the soil samples improved with 5% cement and 5% POFA over a curing period of 7 days met the subbase layer requirements for soil-cement subbase according to the Department of Highways standards for road construction. over a curing period of 7 days met the subbase layer requirements for soil-cement subbase according to the Department of Highways standards for road construction.