Early-age autogenous shrinkage and tensile creep of hooked-end steel fiber reinforced concrete with different thermal treatment temperatures

Thermal shrinkage and autogenous shrinkage usually develop in concrete at early age, which may contribute to the occurrence of cracking when the stress induced from restrained shrinkage is higher than the tensile strength of concrete. Hooked-end steel fiber (SF) is of increasing interest for use to reduce the cracking potential of concrete. Since the restrained stress can be reduced by early-age tensile creep (TC), the accurate assessment of the cracking potential of concrete requires quantification of the early-age TC. However, investigation on the influence of hooked-end SF and thermal treatment temperature on the early-age TC of concrete under a constant tensile load remains lacking. Accordingly, the early-age autogenous shrinkage and TC of hooked-end SF reinforced concrete with different thermal treatment temperatures were investigated in the current study. The increase of the content of hooked-end SF decreased the early-age autogenous shrinkage and TC of the concrete. The early-age autogenous shrinkage of hooked-end SF reinforced concrete increased, while the TC decreased with an increase of the thermal treatment temperature at the same equivalent age. A modified model for predicting the early-age specific basic TC of concrete considering the influence of hooked-end SF and thermal treatment temperature was proposed.