Experimental Study on Early-Age Cracking Behavior of Hooked-End Steel Fiber–Reinforced Concrete under Different Curing Temperatures

Abstract

Steel fiber is the most widely used type of fiber in concrete because of its advanced and economical manufacturing facilities, reinforcing effect, and ability to cope with changing environmental conditions. The use of steel fiber in concrete can reduce the amount of reinforcement used and increase the crack resistance of concrete, which extends the service life of concrete structures, reduces the frequency of maintenance and repairs, and consequently lowers energy consumption and emissions. Many studies focus on the postcracking behavior of steel fiber–reinforced concrete (SFRC). However, it is also crucial to examine the precracking behavior of SFRC at early age. A temperature stress test machine (TSTM) was used to investigate the autogenous shrinkage (AS), tensile creep (TC), and cracking behavior of hooked-end SFRC (HSFRC) at early age under uniaxial constant restrained condition. Analysis and experimental findings demonstrated that (1) the addition of steel fiber increased the splitting tensile strength and modulus of elasticity of HSFRC. The 1-, 3-, and 7-day splitting tensile strength and modulus of elasticity increased with an increase in curing temperature. However, a decrease was observed at 28 days as the curing temperature increased; (2) increasing steel fiber content had a significant influence on reducing TC and AS of HSFRC. TC and AS of HSFRC increased with increasing curing temperature; and (3) early-age cracking potential of HSFRC decreased as steel fiber content increased. Increased curing temperature resulted in a concomitant elevation in the potential for early-age cracking in HSFRC.