Mechanical and Durability Properties of Poorly Graded Sandy Soil Stabilized with Activated Slag

Abstract

This study focused on the evaluation of the mechanical and durability aspects of stabilized poorly graded sandy soil by activated blast furnace slag cements (ASCs) with three different activators with combinations of Na2SiO3 and NaOH (PN), Na2CO3 and Ca(OH)2 (PC), and Na2SO4 and Ca(OH)2 (PS). Type of activators, binder percentage, and curing time were investigated as parameters. The results of unconfined compression strength (UCS) of samples in a constant amount of binder/soil (5-wt%) showed an increase from 0.75-MPa for ordinary portland cement (OPC)-based samples to 2.28, 2.63, and 4.5-MPa for PC-, PN-, and PS-based samples, respectively. Due to its high UCS sample value, the activator considered most effective is PS based. The formed gel between the soil’s particles results from the dense microstructure and fewer voids in the sample suggests a higher interaction level between soil and binder. PS- and PC-based binders showed more ductility than OPC-based stabilized soil. Moreover, ASC samples showed better soundness than OPC samples, due to less volume changes, stronger bonds between soil particles, binder matrix, and absence of destructive expansion.