*Article* **Experimental Study on Durability of Hybrid Fiber-Reinforced Concrete in Deep Alluvium Frozen Shaft Lining**

**Zhishu Yao, Yu Fang, Ping Zhang and Xianwen Huang \***

School of Civil Engineering and Architecture, Anhui University of Science and Technology, Huainan 232001, China; zsyao@aust.edu.cn (Z.Y.); fy18956925891@163.com (Y.F.); Zhangping940813@163.com (P.Z.)

**\*** Correspondence: 162100003@stu.just.edu.cn; Tel.: +86-183-6289-1238

**Abstract:** This article proposes hybrid fiber-reinforced concrete (HFRC) mixed with polyvinyl alcohol fiber (PVA) and polypropylene steel fiber (FST) as a wall construction material to improve the bearing capacity and durability of frozen shaft lining structures in deep alluvium. According to the stress characteristics and engineering environment of the frozen shaft lining, the strength, impermeability, freeze–thaw damage, and corrosion resistance are taken as the evaluation and control indexes. The C60 concrete commonly used in freezing shaft lining is selected as the reference group. Compared to the reference group, the test results show that the compressive strength of HFRC is similar to that of the reference concrete, but its splitting tensile strength and flexural strength are higher; according to the strength test, the optimum mixed content of 1.092 kg/m<sup>3</sup> PVA and 5 kg/m3 FST are obtained. According to the impermeability test results, the mixing of PVA and FST can improve the impermeability resistance of concrete. For the freeze–thaw cycle test results, the mixing of PVA and FST can improve the frost resistance of concrete; based on the 120 days sulfate corrosion test, the mixing of PVA and FST will improve the corrosion resistance of concrete.

**Keywords:** freezing shaft sinking; shaft lining structure; uneven pressure; hybrid fiber-reinforced concrete; durability
