The application of thermal analysis, XRD and SEM to study the hydration behavior of tricalcium silicate in the presence of a polycarboxylate superplasticizer

• The initial hydration process of C3S is markedly retarded by PC.
• The decomposition temperature of Ca(OH)2 is slightly lower after PC modification.
• The adsorption amount of PC on C3S increases progressively with the hydration time.
• The size of Ca(OH)2 crystals are changed due to the adsorption of PC.

Hydration behavior of tricalcium silicate (C3S) in the presence of a polycarboxylate (PC) superplasticizer was investigated by means of isothermal calorimetry, differential thermal analysis and X-ray diffraction. In addition, the adsorption characteristics of PC and morphology change of Ca(OH)2 crystals were also examined, respectively. The results showed that initial hydration process of C3S was markedly retarded by PC and the retardation effect depended on the dosage of PC. The decomposition temperature of the Ca(OH)2 was slightly lower after PC modification. Moreover, the size of Ca(OH)2 crystals were found to be changed due to the adsorption of PC. The results obtained in this research allowed us to gain insights into the interactions between PC and cement.