Predicting the mechanical behaviour of a sandy clay stabilised with an alkali-activated binder

Abstract

There is a growing interest in the geomechanical behaviour of low performing soils strengthened with alkali-activated materials, which have been promoted as low-carbon-footprint binders. This paper focuses on the performance of a sandy clay stabilised with NaOH-activated blast furnace slag after short (28 days) and long (90 days) curing periods. Triaxial compression experiments were conducted at a range of mean effective stresses (41 to 600 kPa) and overconsolidation ratios (1 to 12.2). The experimental data was used to calibrate a kinematic hardening constitutive model and the ability of the model to capture the behaviour of artificially stabilised sandy clay was investigated. Triaxial results carried out on the stabilised soil at both curing periods showed a behaviour resembling that observed for cement-mixed clays. The model, which had never been tested in artificially stabilised soils, successfully predicted the smooth elastoplastic transition observed on the non-stabilised soil specimens and the peak/residual shear strains and strain-softening behaviour after peak strengths in its stabilised state after 28 and 90 curing days.