C100高性能混凝土在冻结井筒井壁中的应用

    Application of C100 high performance concrete in freezing shaft wall

    • 摘要: 为减薄冻结井筒设计井壁的厚度,同时避免大体积混凝土水化热造成的井壁开裂问题,赵固二矿西风井采用了C100高性能混凝土作为井筒深部井壁材料。经过多次、多地原材料比选后,确定了P.II52.5硅酸盐水泥、抗压强度为148 MPa的玄武岩碎石、细度模数为2.8的机制砂、低温早强保坍型聚羧酸盐高性能减水剂作为C100高性能混凝土的原料。通过配合比试验,确定了水泥∶砂∶碎石∶掺合料∶矿粉∶水∶减水剂为395∶600∶1 100∶120∶100∶105∶29的配合比。经过现场实际应用,最终C100冻结段井壁未出现任何裂缝,保证了良好的承压、封水性能。井壁浇筑28 d后,通过现场取样进行强度实测,检测结果表明C100高性能混凝土达到设计强度等级的117%,超过了井巷工程混凝土强度的最低要求为设计强度1.15倍的标准。

       

      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.

       

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