Performance of Calcium Aluminate Cementitious Materials in the Presence of Sodium Chloride

This study investigates the performance of two cementitious systems exposed to sodium chloride solution and thermal cycling. The two systems consisting of an ordinary portland cement (OPC) and a calcium aluminate cement (CAC). Several experimental techniques were conducted to evaluate the performance of OPC and CAC pastes exposed to different concentrations of sodium chloride (NaCl) solution and thermal cycling. X-ray powder diffraction was used to study the hydration products. Low-temperature differential scanning calorimetry was used to detect phase changes and study potential chemical interactions between pastes and NaCl solutions. A longitudinal guarded comparative calorimeter equipped with acoustic emission was used to detect phase changes and damage development in pastes saturated with NaCl solutions during thermal cycling. Unlike OPC pastes that can chemically interact with NaCl solutions to form a destructive chemical phase change at temperatures range between -5 degrees C and 8 degrees C, CAC pastes showed no chemical interactions with NaCl solutions, mainly due to possessing different chemistry than the OPC. As a result, no damage associated with the chemical phase change was observed in CAC pastes, indicating that the CAC is more chemically resistant to NaCl damage than OPC. (c) 2020 American Society of Civil Engineers.