Influence of freeze–thaw cycles and sulfate corrosion resistance on shotcrete with and without steel fiber

•Durability of frost and sulfate resistance of shotcrete with and without steel fiber was tested.•Original performances include relative dynamic elastic modulus and weight loss rate, and relative mechanical properties were measured.•Damage mechanisms of shotcrete by freeze–thaw and sulfate attack were analyzed.•Shotcrete had better durability than ordinary concrete, whereas steel fiber reinforced shotcrete had the best durability. Shotcrete with low-alkali accelerator has short final setting time, high early strength, and various hydration products and microstructures because of different hydration processes of ordinary concrete without accelerator. In tunnel operation processes, a shotcrete single-layer lining structure is subjected to positive and negative temperature alternation and corrosion ions, particularly sulfate ion. The durability and service life of the lining structure are seriously threatened. In this study, the performances, including relative dynamic elastic modulus, mass loss ratio, and mechanical properties after corrosion, were tested to investigate the shotcrete durability of frost and sulfate resistance. Then, mineral composition, thermal analysis, pore structure, and microscope analysis of the specimen before and after corrosion were characterized. To achieve this objective, ordinary concrete and accelerated shotcrete with and without steel fiber were fabricated. Results showed that ordinary shotcrete was more durable under the action of freeze–thaw cycles and sulfate ion attack than that of the ordinary concrete with the same mixture. Thus, steel fiber led to a considerably dense microstructure in the shotcrete matrix, and it could significantly improve the early-age compressive and splitting tensile strengths. Steel fiber reinforced shotcrete had the best durability performance in frost and sulfate resistance.