Drying shrinkage of hardened cement paste under different temperature

Abstract

Length-change isotherm and desorption isotherm of hardened cement pastes whose water to cement ratio is 0.55 and cements used are ordinary Portland cement, moderate heat portland cement, and low heat portland cement were measured in 20 °C and 40 °C degrees Celsius. In addition, vapor adsorption isotherm for BET surface area, Young's modulus and Poisson's ratio for bulk modulus under compressive loading test, and density of hardened cement paste and water content were measured. As a result, the higher temperature showed smaller water content and smaller shrinkage under desorption process. This phenomenon can be explained by the hydrophobic properties of the surface of the hardened cement paste in the higher temperature condition or the temperature and relative humidity dependency of surface area of hardened cement paste. Both hypothesis are reasonable and consistent with existing reports.