Peat soil improvement using cement and quarry dust

Abstract

Peat soil is one of the soil types available in Malaysia, which has a high compressibility and low shear strength. Thus, peat is considered inappropriate to support a construction site in its natural state. Among the methods suitable for the stabilization of peat soil is using a cement. However, the quantity of cement required in peat stabilization is quite large and made this method not too environmentally friendly due to carbon dioxide, CO2 emission from the cement production. Therefore, in this study, quarry dusts are used to partially substitute to ordinary Portland cement in peat soil stabilization. Quarry dusts were expected to potentially act as a pozzolan (containing cementitious properties to replace cement). Laboratory testing to determine the physical, chemical and mechanical properties were carried out to investigate the strength, acidity and the microstructure of the treated and untreated peat soil. For mechanical properties, Unconfined Compressive Strength test (UCS), was conducted to determine the peat soil strength., Chemical and microstructure (Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray (EDX)) tests were carried out to assess the mechanism of strength gain in the stabilized peat soil. The results obtained show that by partially replacing the cement with 5% quarry dust, the soil strength increases from 47 to 684 kN/m2, which suitable for low loading construction such as car park area and outdoor sport court. The microstructural results also show PC and PCQ5 increases the calcium, Ca and decreases the carbon dioxide, which has an effect on increasing strength and decreasing the soil acidity.