含高矿化度水地层深立井井壁高强混凝土耐久性研究

Study on durability of high strength concrete wall of deep shaft with high salinity water stratum

为防止穿越高矿化度水地层深立井井壁遭受腐蚀而影响安全运营,开展了硫酸盐全浸泡下井壁高强混凝土耐久性研究。通过3种不同水胶比混凝土和2种经防腐处理的混凝土在硫酸盐环境中侵蚀180d的抗压强度、质量损失、相对动弹性模量等性能对比试验,来研究高强混凝土的性能。试验结果表明:在各侵蚀浓度下混凝土试件的抗压强度、质量与相对动弹性模量随龄期都呈现出先缓慢增长后加速减小的趋势,相对动弹性模量与抗压强度的变化趋势有着高度的相似性;水胶比越小混凝土密实性越好,硫酸根离子在混凝土内部的传输受到抑制,对混凝土的侵蚀性越小,井壁耐久性越好,水胶比为0.26的混凝土在整个侵蚀周期内抗硫酸盐侵蚀性能表现最佳;在水胶比不变的前提下,内掺防腐剂对提升混凝土抗硫酸盐侵蚀性能具有一定效果,而采用抗硫酸盐水泥的防腐措施在较高浓度硫酸盐侵蚀条件下适用性较差。本研究结果可为西北地区穿越高矿化度水地层深立井井壁混凝土配制提供参考。

In order to prevent the shaft wall of deep vertical shaft crossing high salinity water stratumfrom being corroded and affecting safe operation,the durability of high strength concrete of shaft wallunder sulfate immersion was studied.The compressive strength,mass loss and relative dynamicelastic modulus of three kinds of concrete with different water-binder ratio and two kinds of concretewith anti-corrosion treatment eroded in sulfate environment for 180 days were compared.The resultsshow that the compressive strength,mass and relative dynamic elastic modulus of concrete specimensunder different erosion concentrations show a trend of slow growth and then accelerated decrease withage,and the change trend of relative dynamic elastic modulus and compressive strength was highlysimilar.The smaller the water-binder ratio was,the better the compactness of the concrete was,thetransmission of sulfate ions in the concrete was inhibited,the less the erosion of the concrete was,andthe better the durability of the shaft wall was.The concrete with a water-binder ratio of 0.26 had thebest resistance to sulfate attack during the entire erosion cycle.Under the premise of constant water-binder ratio,the addition of preservatives had a certain effect on improving the sulfate resistance ofconcrete,while the anti-corrosion measures using sulfate-resistant cement had poor applicability underthe condition of high concentration sulfate erosion.The results of this study could provide referencefor the preparation of shaft lining concrete in deep vertical shafts crossing high salinity water strata inNorthwest China.