摘要
为了提高强硫酸盐渍土地区现浇混凝土的抗腐蚀性能,开展了煅烧偏高岭土等质量替代水泥比例为 0、5%、15%、25%、50%的现浇混凝土试件,分别在清水、5%Na2SO4、10%Na2SO4 和 10%Na2SO4+10%NaCl溶液中的长期浸泡试验,分析了试件在 1 d、3 d、7 d、14 d、28 d和 90 d龄期时的抗折强度、抗压强度、相对动弹性模量、质量损失率、体积膨胀率和有效孔隙率的变化规律.研究结果表明:(1)掺入煅烧偏高岭土可提高现浇混凝土的抗折强度、抗压强度和抗腐蚀性能,掺量为 25%时,试件的抗折强度和抗压强度最高,相对动弹性模量变化最稳定,抗硫酸盐侵蚀性能最好.(2)煅烧偏高岭土可以改善混凝土的内部孔隙结构,降低现浇混凝土的有效孔隙率和质量损失率,使试件的体积稳定性明显提高.研究成果可为煅烧偏高岭土提升现浇混凝土在强硫酸盐渍土地区的工程应用提供一定的理论基础.
Abstract
To improve the corrosion resistance of cast-in-place concrete in regions with potent sulfate-saline soils,calcined metakaolin was used to replace 0,5%,15%,25%,and 50%cement.Prolonged immersion tests were conducted in pure water,5%Na2SO4,10%Na2SO4,and 10%Na2SO4+10%NaCl solution.The flexural strength,compressive strength,relative dynamic modulus of elasticity,mass loss rate,volumetric expansion rate,and effective porosity of the specimens at 1 d,3 d,7 d,14 d,28 d,and 90 d of age were examined.The results show that(1)The addition of calcined metakaolin improves the flexural strength,compressive strength,and corrosion resistance of cast-in-place concrete.When the content of calcined metakaolin is 25%,the specimens exhibit optimal flexural and compressive strength,the most stable relative dynamic modulus of elasticity,and superior sulfate attack resistance.(2)Calcined metakaolin effectively reduces the effective porosity and mass loss rate of cast-in-place concrete while significantly improving the volumetric stability of the specimens.These research results can offer a theoretical foundation for the engineering application of calcined metakaolin in elevating cast-in-place concrete performance within sulfate-saline soil environments.
基金项目
新疆生产建设兵团重点领域科技攻关计划(2019AB016)
国家自然科学基金(52168035)
新疆生产建设兵团区域创新引导计划(2018BB045)
万方数据