High-temperature resistance of high-strength concrete with iron tailing sand

Abstract

High-strength concrete with iron tailing sand (IT-HSC) was developed to alleviate resource shortages and improve construction cost-effectiveness. To develop a green IT-HSC with good high-temperature resistance, four different concrete compositions were designed and exposed to 20, 100, 300, 500, and 700 °C to test the effects of temperature, air-entraining agent, steel fiber, and polypropylene fiber on IT-HSC. Combined with macroscopic test and microscopic analysis, the results show that with the increase in temperature, the residual mechanical properties of the four IT-HSCs first increased and then decreased with increasing temperature. The mass-loss rate gradually increased, but the elastic modulus continued to decrease with increasing temperature. When the temperature reached 100 °C and 300 °C, the compressive strength, split tensile strength, and the ratio of tension to compression of IT-HSC increased slightly. Among them, the steel fiber greatly improves the splitting tensile strength of IT-HSC, and the polypropylene fiber and air-entraining agent significantly inhibit the explosive spalling of IT-HSC, but the addition of the air-entraining agent greatly reduces the mechanical strength of IT-HSC.