Effect of superplasticizers on hydration kinetics of ultrafine sulfoaluminate cement-based grouting material

Highlights: • The effect of superplasticizers on the hydration kinetics of USCBGM was studied. • FDN retarded the hydration during acceleration period but PCE did not. • FDN can better promote hydration during deceleration period compared with PCE. • PCE significantly hindered the hydration at stabilization period compared with FDN. • Both FDN and PCE changed the kinetic reaction process of USCBGM from NG-I-D to NG-D. The effect of naphthalene superplasticizer (FDN) and polycarboxylate superplasticizer (PCE) on hydration kinetics of ultrafine sulfoaluminate cement-based grouting material (USCBGM) was studied. The results showed the hydration process of USCBGM was divided into acceleration, deceleration and stabilization period, being controlled by nucleation (NG), phase boundary reaction (I) and diffusion (D) respectively, which were well simulated through Knudsen and Kondo models. FDN retarded the hydration of USCBGM in acceleration and stabilization period, but promoted the hydration during deceleration period. PCE did not significantly affect the hydration in acceleration period, but also can promote the hydration in deceleration period. However, PCE had less effect on hydration during deceleration period compared with FDN. Moreover, PCE can obviously retard the hydration in stabilization period. The reaction controlled process of USCBGM changed from NG-I-D to NG-D whether FDN or PCE was added according to the fitting results of hydration kinetics.