Effect of Sodium Silicate and C-S-Hs-PCE on Properties of LS-Cement Binder

Abstract

This research investigated the synergistic adoption of sodium silicate (SS) and the synthetic calcium silicate hydrates (C-S-Hs)/polycarboxylate (PCE) nanocomposites on the hydration behavior of portland cement containing 20% by weight of lithium slag (LS). Effects of SS and C-S-Hs-PCE on rheological performance, mechanical strength development, and hydration process were evaluated. Results showed that C-S-Hs-PCE was advantageous for modifying the rheological performance of fresh LS-cement binder, while SS increased the rheology and yield stress and shortened setting time of the LS-cement binder. C-S-Hs-PCE promoted the hydration of silicates to form abundant CH, and SS generated the dissolution of metallic ions from LS. The hastened dissolution of LS accelerated the formation of ettringite (AFt) as well as C-S-H gel. Because the hydration of cement and pozzolanic reaction of LS were both promoted, the hydration products of hardened matrix were increased, and the interlaced combination structure of hydrates in the matrix was greatly improved, which was favorable for the development of mechanical strength. The findings provide theoretical guidelines for modifying the properties of blended cements by uniting nanoparticles and chemicals.