Effect of LDH on the dissolution and adsorption behaviors of sulfate in Portland cement early hydration process

Abstract

In recent years, it has been widely recognized that the incorporation of Mg-Al-LDH into cement-based materials can improve the salt corrosion resistance of cement-based materials. The reason for the improvement comes from the anion adsorption capacity of Mg-Al-LDH. It was confirmed that the addition of Mg-Al-LDH would accelerate the setting and hardening of cement paste. With the increase in the Mg-Al-LDH content, the initial setting time of cement slurry with different gypsum contents will decrease by 10-50% and the viscosity of the cement slurry will increase by 100-200%. Depending on different gypsum contents, the degree of cement hydration varied. This article also found that the gypsum in the cement has a negative effect on the resistance to salt erosion, which was brought about by the Mg-Al-LDH adsorption capacity.