Abstract: To investigate the impact of sodium gluconate on the hydration behavior of cement slurry containing high-volume limestone powder, we employed isothermal calorimetry, X-ray diffraction test, and thermogravimetric test to examine the hydration process and changes in types and content of hydration products in the cementitious material system. We also explored the mechanism of nucleation and growth of hydration products under the influence of sodium gluconate by using the phase boundary nucleation and growth model. Results demonstrate that sodium gluconate delays the hydration of cement containing high-volume limestone powder, leading to decreased generation of hydration products and a reduction in overall hydration degree. Moreover, sodium gluconate suppresses the rate of early nucleation and growth of hydration products, resulting in a decreased area of early nucleation and growth at phase boundary.

Key words: sodium gluconate, large dosage limestone powder, hydration process, hydration product, hydration kinetics