Effects of Wetting-Drying Cycles on Physical and Mechanical Properties of Cement Mortar

Document Type : Research Paper

Authors

Abstract

In many construction projects, cement mortar is affected by wetting-drying cycles, often due to factors such as varying rainfall, evaporation, changes in level of water in reservoirs. Alternative interactions between water and mortar affects the physical and mechanical properties of cement mortar and accelerates its erosion.Therefore, evaluating the effect of wetting-drying cycles on the physical and mechanical properties of cement mortar seems to be essential. For this purpose, a number of cylindrical and disc shaped samples were prepared.Samples were prepared for uniaxial compression test, Brazilian test, effective porosity test,and also determining longitudinal wave velocity. Samples were examined in cycles 0, 1, 5, 10, 15, 20 and 25.In each cycle, the samples were saturated in water for 24 hours and then dried at 105 ° C for 24 hours; then the samples were cooled at room temperature and finally examined. After cycle 25, uniaxial compressive strength,Brazilian tensile strength, modulus of elasticity and longitudinal wave velocity decreased by 37.96, 36.72, 35.44 and 8.1 percent, respectively; while porosity increased by 7.6 percent.

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