Durability analysis of seashore saline soil bound with a slag compound binder

Abstract

In this paper, a slag compound binder (hereinafter referred to as the SM binder) was used to bind seashore saline soil. Compressive tests, scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction analytical tests were carried out to measure the unconfined compressive strength, observe the microstructure, analyze the composition of hydration products and evaluate the binding mechanism of the saline soil/SM binder mixture. The results showed that calcium silicate and calcium aluminate hydrates were produced after the hydration of the cinder components in the SM binder. Part of the calcium aluminate hydrate reacted with the gypsum to form ettringite, while the other part reacted with the Cl− and SO42− in the saline soil to produce Kuzel’s salt. Na+ also participated in the hydration reaction and produced zeolite-like substances. These hydration reactions led to the rapid binding of the soil sample. As the surface of the saline soil particles also contained active SiO2 and A12O3, the Ca(OH)2 reacted with them to form calcium silicate and calcium aluminate hydrates in a continuously alkaline environment. Such reactions contributed to the third-stage binding of the saline soil, leading to a gradual increase in the strength of the soil samples during the middle and late stages of binding.