In this study,the electrical resistivity tester and electro-acoustic ζ-potential analyzer were used to test the resistivity and ζ-potential of low-heat Portland cement pastes and ordinary Portland cement pastes,respectively,so as to explore the early hydration characteristics of low-heat Portland cement. The results demonstrate that the resistivity and ζ-potential curves have good consistency in characterizing the hydration process of the cement pastes;within 20 min of hydration,the ζ-potential of the low-heat Portland cement pastes is directly proportional to the Ca2+ concentrations;the sharply rise of ζ-potential is related to {Ca6[Al(OH)6]2·24H2 O}6+ concentrations;after 20 min of hydration,ettringite (AFt)and calcium silicate hydrates (CSH)begin to form in the low-heat Portland cement pastes. Besides,the change of ζ-potential is influenced by not only the reaction rate of SO42- and {Ca6[Al(OH)6]2·24H2 O}6+ but also the reaction rate of Ca2+ and HSiO3- . Compared with ordinary Portland cement,the low-heat Portland cement has a faster Ca2+ dissolution rate within 20 min of hydration,and the time of AFt formation is earlier in the low-heat Portland cement pastes;however,the induction period,which is mainly affected by the nucleation and growth rate of Ca(OH)2 crystals and osmotic pressure control,is shorter. During the deceleration period,the curve’s slope Km of resistivity correlating with the logarithmic of time for low-heat Portland cement pastes is slightly smaller,indicating that the hydration rate of the low-heat Portland cement stone increases during the acceleration period,and hydrates filled the pores,which resulted in that the rate of shortening is faster for the pore spacing,and the rate of structural compaction is slightly slower during the deceleration period. © 2023 Cailiao Daobaoshe/Materials Review. All rights reserved.
