摘要
为解决滨海地区混凝土在硫酸铵环境中耐久性不足的问题,本研究采用了不同的水灰比(w/b)和表面涂层处理对混凝土在硫酸铵浸润下的抗侵蚀性能进行了系统评估。通过对混凝土试样施加胶体硅酸盐、硅烷/纳米复合材料、乙烯基酯/纳米复合材料等涂层,并在基准浸润和复合浸润(冻融循环和干湿循环)条件下进行质量变化及微观结构的演变等测试。研究结果表明:与基准浸润条件相比,复合浸润对混凝土的破坏更为严重。将水灰比由0.6降低至0.4后,涂覆纯乙烯基酯的混凝土试样与无涂层试样相比,累积质量损失减少了约55%,降低水灰比会使混凝土的微结构致密化并降低渗透性。胶体硅酸盐表面处理虽然改善了初始流体抵抗性,但是由于胶体硅酸盐的亲水性和涂层的干缩微裂纹,未能有效保护混凝土抵抗硫酸铵侵蚀。水灰比为0.6,采用硅烷/纳米复合材料涂层时,由于其疏水性和纳米材料的增强效果,混凝土试样的累积质量损失相对涂覆纯硅烷的试样最多可减少56%,水灰比为0.4,采用乙烯基酯/纳米复合材料的涂层时,由于聚合物膜的强黏结性和化学稳定性,混凝土试样的累积质量损失相对涂覆纯乙烯基酯的试样最多可减少65%。硅烷和乙烯基酯纳米复合材料均在滨海地区混凝土的硫酸铵侵蚀防护中均表现出良好的效果,为滨海地区混凝土结构的设计和维护提供了有效的防护措施,可以显著延长混凝土结构在硫酸铵环境中的使用寿命,减少维修和更换成本。
To address the problem of insufficient durability of concrete in ammonium sulfate environments in coastal areas,this study systematically evaluated the durability of concrete under ammonium sulfate infiltration using different water-cement ratios(w/b)and surface coating treatments.The concrete specimens were coated with colloidal silicate,silane/nanocomposite,and vinyl ester/nanocomposite coatings,and the mass change,and microstructural evolution were tested under baseline infiltration and composite infiltration(freeze-thaw cycle and dry-wet cycle)condition.The results show that composite infiltration caused more serious damage to concrete than baseline infiltration.After reducing the water-cement ratio from 0.6 to 0.4,the cumulative mass loss of the concrete specimens coated with pure vinyl ester is reduced by about 55%compared with the uncoated specimens.Reducing the water-cement ratio densifies the microstructure of concrete and reduces permeability.Although the colloidal silicate surface treatment improved the initial fluid resistance,it failes to effectively protect the concrete due to its hydrophilicity and the shrinkage microcracks of the coating.When the water-cement ratio is 0.6,the cumulative mass loss of the concrete specimen with the silane/nanocomposite coating can be reduced by up to 56%compared with the specimen coated with pure silane due to its hydrophobicity and the enhancement effect of the nanomaterial.When the water-cement ratio is 0.4,the cumulative mass loss of the concrete specimens coated with vinyl ester/nanocomposite can be reduced by up to 65%relative to the specimens coated with pure vinyl ester due to the strong bond and chemical stability of the polymer film.Both silane and vinyl ester nanocomposites show good results in the protection of concrete from ammonium sulfate corrosion in coastal areas,providing effective protective measures for the design and maintenance of concrete structures in coastal areas,which can significantly extend the service life of concrete structures in ammonium sulfate environments and reduce maintenance and replacement costs.
作者
谭洁
胡伟
刘洋
TAN Jie;HU Wei;LIU Yang(Yangtze River Waterway Survey and Design Institute(Wuhan)Co.,Ltd.,Wuhan 430000,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)
出处
《硅酸盐通报》
北大核心
2025年第2期474-489,共16页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金(52079056)。
