Combined effect of lignosulfonate and carbonate on pure portland clinker compounds hydration. III. Hydration of tricalcium silicate alone and in the presence of tricalcium aluminate

The effect of carbonate and/or lignosulfonate on the hydration of C₃S alone and in the presence of C₃A has been examined by DTG and TG curves and by zeta potential measurements. The combined addition of sodium carbonate and lignosulfonate strongly retards C₃A hydration. However by mixing 20 % C₃A with C₃S the retarding effect is significantly lower. On the other hand the early C₃A hydration is completely blocked by sodium carbonate and lignosulfonate simultaneously added. It seems that the fluidifying effect of the combined addition of those admixtures could be ascribed to both the dispersing action and the completely blocking effect on the early C₃A hydration.