地铁工程用抗渗高阻抗混凝土制备技术及优化设计

PREPARATION TECHNOLOGY AND OPTIMIZATION DESIGN OF IMPERMEABLE AND HIGH IMPEDANCE CONCRETE FOR SUBWAY ENGINEERING

为了得到抗渗和力学性能均佳且适用于地铁工程用的高阻抗混凝土,配置出了强度等级为C50的高性能混凝土。在基准配比的基础上,开展了混凝土的工作性能、抗渗性能、电阻率以及力学性能试验,研究了不同水灰比(0.30、0.35、0.40、0.45和0.50)、不同粉煤灰(质量分数为0%、2%、4%和6%)和减水剂掺量(质量分数为0%、2%、4%和6%)对混凝土性能的影响规律及内在机理。结果表明:水灰比、粉煤灰和减水剂均对混凝土抗渗性能和电阻率影响显著,其改善效应由高往低依次为水灰比、粉煤灰、减水剂;随着水灰比的增加,混凝土抗渗性能和电阻率随之减小;粉煤灰和减水剂掺量的增加对混凝土抗渗和抗导电性能均有提高作用。本研究所配置的抗渗高阻抗混凝土满足地铁工程施工和力学性能的要求。

In order to obtain high impedance concrete with excellent impermeability and mechanical properties suitable for subway engineering,high-performance concrete with a strength grade of C50 was configured.On the basis of the benchmark ratio,experiments were conducted on the workability,impermeability,electrical resistivity,and mechanical properties of concrete.The effects of different water cement ratios(0.30,0.35,0.40,0.45,and 0.50),different fly ash(mass fractions of 0%,2%,4%,and 6%),and water reducing agent dosages(mass fractions of 0%,2%,4%,and 6%)on the performance of concrete were studied,as well as their underlying mechanisms.The results show that the water cement ratio,fly ash,and water reducing agent all have a significant impact on the impermeability and electrical resistivity of concrete,and their improvement effects are in order of water cement ratio,fly ash,and water reducing agent from high to low、As the water cement ratio increases,the impermeability and resistivity of concrete decrease accordingly、The increase in the amount of fly ash and water reducing agent can improve the impermeability and conductivity of concrete.The impermeable and high impedance concrete configured in this research institute meets the requirements of subway construction and mechanical properties.