Influence of Curing Time on the Pore Structure of the Phosphoaluminate Cement Concrete

In this paper, the effect of curing time on the mechanical property and pore character of the phosphoaluminate cement concrete (PAC) was studied in detail. The phase composition and morphology of hydration products of cement were analyzed with X-ray diffraction (XRD). In addition, the pore character and electrical property of concrete were also researched with surface area and porosity analyzer (BET), mercury intrusion porosimetry (MIP) and electrochemical impedance spectroscopy (EIS). The results show that the effect of curing time on the pore structure of concrete is obvious. The main hydration products of PAC are micro-crystal phase and gel of phosphate and phosphoaluminate. In addition, there are no calcium hydroxide (CH) and ettringite (AFt) produced during the process of hydration. The compressive strength of PAC increased with age, and the micro structure changed, as well. Moreover, the AC resistance analysis manifested as the change of the nyquist pattern and resistance value of PAC concrete.