Effects of strain rate, temperature and freeze–thaw cycle on the mechanical properties of cement mortar composite specimen

Abstract

AbstractThe effects of the strain rate, water/cement ratio, temperature and number of freeze–thaw cycle on the ultimate compressive strength, peak strain and elastic modulus of cement mortar composite specimens were studied using uniaxial compression test. Test results show that: (a) The strength difference of cement mortar composite specimens is not significant when the axial loading direction is parallel to the interface of two components with different water/cement ratios under low strain rate loading. The strength of cement mortar composite specimens mainly depends on the one with lower strength, and the strength of cement mortar specimen with high strength is more sensitive to the strain rate than that of cement mortar specimen with low strength. (b) With the increase of temperature from 25°C (room temperature) to 500°C, the strength of the specimen with high compressive strength will increase first and then decrease. Nevertheless the strength of the specimen with low compressive strength will gradually decrease. The strength of cement mortar composite specimen will decrease with increased number of freeze–thaw cycle. (c) Under the same strain rate, after the same high temperature or the same number of freeze–thaw cycle, the peak strain of the composite specimens composed of two water/cement ratio components is much larger than that of the specimen composed of only one component; conversely, the elastic modulus shows an opposite trend.