Tests on strengths of steel strand and strand‐concrete (or cement slurry) bond stress under cryogenic temperatures

This paper experimentally studied the strengths of the steel strand and strand‐concrete (or cement slurry) bond stress under different cryogenic temperatures ranging from 20 to −160 °C. Twenty one tensile tests were firstly carried out to obtain the yield and ultimate strengths of the steel strand under different cryogenic temperatures. The influences of the cryogenic temperatures on the yield strength, ultimate strength, and fracture strain of the steel strand were discussed and analyzed. Sixty six pull‐out tests with 3 identical specimens for each parameter were carried out to obtain the ultimate strength behaviors of the strand‐concrete (or cement slurry) bond. The failure modes, strand‐concrete (or cement slurry) bond stress, and influences of the low temperature and strength of concrete on the bond stress were reported, discussed, and analyzed. Design equations were also developed to predict the yield and ultimate strengths of the steel strand under temperature intervals of 20 to −160 °C, and their accuracies were checked through validations against the test results. Prediction models in the literature were also used to predict the strand‐concrete bond stress, and their accuracies were checked by the reported test results. Empirical design equations were also developed to predict the strand‐cement slurry bond stress at cryogenic temperatures.