Performance and Durability of Laterite Soil Stabilized with Geopolymer Binder Made from Local Bio-Sourced Materials for Road Construction

Abstract This study examines the performance and the durability of the geocomposite obtained by replacing cement by rice husk ash (RHA)-based geopolymer in stabilizing laterite soil for the use in pavement construction. For that laterite soil was first characterized through tests such as Atterberg limits, compaction test, Californian Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS), and X-ray diffraction. Thermogravimetry (TG) coupled with differential (DTG) and X-ray diffraction analysis showed that the calcination of rice husk power (RHP) at 800°C leaded to amorphous silica needed for the geopolymer synthesis. It was found that the optimum geopolymer formulation 80%MK+20%RHA presents the best physical and mechanical performance, achieving a density of 1.61 t/m 3 , a water accessible porosity of 20% and an unconfined compressive strength of 24.6 MPa. The optimum geopolymer formulation was used to stabilize the laterite soil for base layer of pavement. Unconfined compressive strength of geopolymer-stabilized laterite soil is approximately 8% larger than that of cement-stabilized laterite soil. Unconfined tensile strength of geopolymer-stabilized laterite soil is approximately 20% larger than that of cement-stabilized laterite soil. Furthermore, the durability analysis showed that the unconfined compressive strength and the bending strength of geopolymer-stabilized samples decrease up to 70% of the initial compression strength and 75% of the initial bending strength with increasing cyclic wetting-drying, respectively. However, the unconfined compressive strength and the bending strength of geopolymer-stabilized laterite soil are approximately twice those of cement-stabilized laterite soil for a given cyclic number of wetting-drying. The FE simulations of pavement under traffic loading showed that the base layer stabilized with geopolymer and the base layer stabilized with cement present comparable performance regarding the vertical and shear deformation.