Abstract:
In order to reduce the thickness of the frozen shaft and avoid shaft cracking caused by hydration heat of mass concrete, C100 high-performance concrete is adopted as the deep shaft material in the west air shaft of Zhaogu No.2 mine. After multiple and multi-site comparison of raw materials, P.II52.5 portland cement, basalt gravel with compressive strength of 148 MPa, mechanism sand without fineness modulus of 2.8 and low-temperature early-strength collapse-protected polycarbarate high-performance water reducer were determined as the raw materials for C100 high-performance concrete. By mixture ratio test, the C100 concrete cement∶ sand∶ gravel∶ admixture∶ mineral powder∶ water∶ water reducing agent is 395∶600∶1 100∶120∶100∶105∶29. Ultimately, no cracks appeared in the borehole wall of C100 freezing section, which ensured good performance of pressure bearing and water sealing. After 28 days of shaft lining casting, field sampling was conducted to measure the strength. The test results showed that the C100 high-performance concrete reached 117% of the designed strength level, which exceeded the standard of 1.15 times of the designed strength as the minimum requirement for the concrete strength of shaft engineering.