Influence of direct electric curing on the hydration and microstructure of cement paste excluding ohmic heating: Fid-Bau Portal

Influence of direct electric curing on the hydration and microstructure of cement paste excluding ohmic heating

Yang, Zhihan / Xie, Youjun / He, Jionghuang / Wang, Fan / Zeng, Xiaohui / Ma, Kunlin / Long, Guangcheng

Highlights: • A modified isothermal calorimeter was used to measure the hydration heat of DEC cement paste. • The influence of DEC excluding OH effect on fresh cement paste is small. • A theoretical model of simulating electric power per unit mass was established and is well consistent with the measured results.

Abstract A modified apparatus based on isothermal calorimetry was employed to determine the influence of direct electric curing (DEC) on the hydration of cement paste other than ohmic heating effect. In addition, the effects of DEC on the microstructure of cured cement pastes were investigated by TG, XRD, NMR, SEM and MIP. The results show that the heat release of DEC samples at early-age is increased significantly due to the electrical power. However, the hydration and microstructure of DEC samples in the isothermal environment are familiar with the normal curing sample. This indicates that, other than OH effect, the impact of DEC on the hydration process and microstructure of cement is negligible. Moreover, a theoretical model for predicting the electric power evolution related to porosity, free water content, hydration degree and initial electric power per unit mass was established which is matched well with the actual measurement results.