Impacts of C-S-Hs-PCE and Na₂SO₄ on hydration properties of lithium slag-cement composite binder

Synergistic effects of the synthetic calcium silicate hydrates (C-S-H)/polycarboxylate (PCE) and Na₂SO₄ on hydration properties and microstructure of cement-lithium slag (LS) composite binder were analyzed. Results showed that C-S-Hs-PCE and Na₂SO₄ exhibited a synergistic effect on hydration acceleration of LS-cement binder. Na₂SO₄ increased alkalinity of interstitial solution and promoted dissolution of LS. Dissolved Al and Si from LS powder reacted with dissolved SO ₄ ²⁻ from Na₂SO₄ to produce extra hydrates, and C-S-Hs-PCE accelerated pozzolanic reaction as well as hydration reaction via nucleation effect collaborated with dispersing effect. C-S-Hs-PCE accelerated reaction process of Na₂SO₄ via nucleation effect, and activation effect of Na₂SO₄ provided more newly-formed hydrates to act as nucleation seeds or crystal skeleton for the hydration of new phases. Newly formed hydrates promoted exceedingly the appearance of network, leading to a refinement of microstructure.