In-situ and continuous monitoring of pore evolution of calcium sulfoaluminate cement at early age by electrical impedance measurement

•Pore evolution of calcium sulfoaluminate cement is evaluated.•Hydration features associated with microstructure evolution are identified.•Initial formation and evolution of pore structure are analyzed.

This paper investigates the microstructure evolution of CSA cement pastes with different water to cement ratios in various hydration stages. Microstructure information, such as porosity, cumulative and incremental pore volume of cement pastes, is revealed by the innovative non-contact electrical impedance measurement (NCEIM), low temperature differential scanning calorimetry (LT-DSC), nitrogen adsorption test and mercury intrusion porosimetry (MIP). The hydration features associated with microstructure evolution are identified by NCEIM, Micro-Raman spectra and heat evolution test. Through the overall analysis of experimental results, initial formation and evolution of microstructure of CSA cement pastes are identified.