Hydration properties of calcium sulfoaluminate-portland cement blends

Synopsis: The X-ray diffraction analysis and mercury intrusion porosimetry were employed to investigate the hydration process of calcium sulfoaluminate (CSA)-portland cement blends with CAS? mass concentration, CS/CAS?, and CS?/CAS? mass ratios ranging from 7.7 to 22.0%, 1.0 to 6.5, and 0.5 to 1.2, respectively. Owing to the hydration of adequate CAS? contents and the generation of sufficient quantities of expansive ettringite, blends with CA S? amounts as well as CS/CA S? and CS?/CAS? values comprised between 17.6 and 22.0%, 1.0 and 1.7, 0.5 and 1.0, respectively, showed high-early strengths and low drying-shrinkage when compared to normal portland cements. The formation of expansive ettringite was associated with concentrated pore distributions and most preferred pore radii ranging from either 47 to 225 or 367 to 896 nanometers, depending on both CS/CA S? and CS?/CAS? ratios.