Shear Strength of Stabilized Clay Treated with Soda Residue and Ground Granulated Blast Furnace Slag

This study examined soda residue (SR) and ground granulated blast furnace slag (GGBS) to stabilize soft soil in comparison with using portland cement (PC). The shear strength of samples was measured to study the additive dosage and curing time effect on the additive performance. Microstructural investigations were conducted using pH, thermogravimetric analyses, X-ray diffraction, and scanning electron microscopy to correlate with shear strength of the treated soil. The results indicated that the presence of SR can increase the shear strength of soft soil and the optimum content is approximately 30% to yield the highest cohesion. Soil stabilization using a mixture of SR and GGBS increased shear strength as GGBS content and curing time increased. Shear strength of SR-GGBS-stabilized soil was close to that of the corresponding SR-PC-stabilized soil after curing for 28 days. The main hydration products detected for SR-GGBS-stabilized soil included calcium silicate hydrates, calcium aluminate hydrates, ettringite, and calcium chloroaluminate hydrates. The results will contribute to the use of SR and GGBS as effective stabilizers for soft soil.