Strain-Rate Sensitive Behavior of Cemet Paste and Mortar in Compression

The strain-rate sensitivity of the cement paste and mortar constituents of concrete is studied experimentally. Saturated cement paste and mortar specimens are loaded in compression to 15,000 microstrains, 27 to 29 days after casting, using strain rates ranging from 0.3 to 300,000 microstrainslsec. Water-cement ratios of 0.3, 0.4, and 0.5 are used. Strain-rate sensitivity of the materials is measured in terms of the initial elastic moduli, maximum stress, and corresponding strain. The initial elastic moduli and the strength of cement paste and mortar increase by 7 percent and 15 percent, respectively, with each order of magnitude increase in strain rate. The strain at the maximum stress is the greatest for the lowest strain rate. With an increase in strain rate, the strain at the maximum stress first decreases and then increases