Strength characteristics of clay stabilized with fly-ash based geopolymer incorporating granulated slag

Abstract

The use of traditional binders (e.g., lime or cement) in soil stabilization faces many obstacles of environmental nature, and geopolymers have been recently become an attractive alternative binder that may overpasses such obstacles. However, the literature lacks detailed information in relation to the geo-mechanical characteristics of geopolymer-stabilized soils and this paper fills in part of this gap. The paper presents an evaluation of the stress-strain behavior of two natural clays of different mineralogy treated with fly-ash based geopolymer. Laboratory experiments were performed including the Unconfined Compressive Strength (UCS) tests and Consolidated Undrained (CU) triaxial tests under different confining pressures. The results indicate that the addition of geopolymer increases the strength and stiffness of clay, which contributes to higher uniaxial and triaxial peak stresses. The confining pressure was found to have a considerable influence on the stress-strain behavior and excess pore-water pressure obtained from the CU tests. The results also demonstrate that clay mineralogy is an important factor that affects the stress-strain performance of geopolymer-treated clay.