Synergistic effects of C-S-H–PCE and triethanolamine on the hydration kinetics and rheological behaviours of lithium slag composite binder

The influences of calcium silicate hydrate seeds–polycarboxylate ether composites (C-S-H–PCE) and triethanolamine (TEA) on the hydration heat and rheological performances of a binary binder (lithium slag (LS) and cement) were studied. The results demonstrated that C-S-H–PCE could shorten the hydration induction period and increase the hydration heat release. When the C-S-H–PCE dosage was 2%, the initiation time of the hydration acceleration period (t_A) decreased by 0.084 h and the cumulative heat release over 72 h increased by 3.032 J/g. However, the use of TEA retarded the hydration induction period and increased the hydration heat release. When 0.5% and 1% TEA were added to the LS–cement binder with 1% C-S-H–PCE, the values of t_A increased by 113.32% and 127.99% respectively and the cumulative heat of the acceleration period (Q_A-C) increased from 49.38 J/g to 95.90 J/g. With 2% C-S-H–PCE and 0.5% TEA, the exothermic peaks in the acceleration period were obviously enhanced, with Q_A-C reaching 100.444 J/g. Moreover, 2% C-S-H–PCE and 0.5% TEA promoted the reaction rate of crystalline nucleation and crystal growth. The use of C-S-H–PCE increased the rheological properties of the binder, while the use of TEA decreased the rheological performance of the binder. Moreover, a high quantity of TEA (more than 0.5%) in combination with C-S-H–PCE obviously impaired the fluidity of the LS–cement binder.