高浓度硫酸盐环境下桥梁桩基混凝土防腐技术

结合西南某公路桥梁工程桩基混凝土的抗硫酸盐腐蚀需求,研究10%(质量分数)高浓度硫酸盐溶液作用下防腐技术对混凝土抗压强度、抗压强度耐蚀系数及硫酸根离子传输的影响。通过气泡结构和微观形貌分析了防腐技术的作用机理。结果表明,高浓度硫酸盐侵蚀环境下,“膨胀剂+矿物掺和料”类防腐剂防腐效果表现为早期优异后期破坏严重,“盐结晶抑制”类防腐剂长期抗腐蚀效果更优。矿物掺和料、“膨胀剂+矿物掺和料”类防腐剂主要通过提升密实度和优化孔径分布来延缓硫酸根的侵入,而“盐结晶抑制”类防腐剂既可一定程度优化混凝土孔隙结构,又可抑制结晶性膨胀产物的生成。

Anti-Corrosion Techniques of Bridge Pile Foundation Concrete in High-Concentration Sulfate Environment

As the demand for sulfate resistance of pile foundation concrete of a highway bridge in the Southwest of China, the influences of anti-corrosion techniques on concrete compressive strength, corrosion resistance coefficient of compressive strength and sulfate-ion transport under 10% (mass fraction)-sulfate solution were investigated. The mechanism of anti-corrosion techniques was analyzed by air-void structure and micro morphology. The results show that the corrosion resistance of "expansive agent with supplementary cementitious materials" admixtures is excellent in the early stage but serious in the later period, and the corrosion resistance of "salt crystallization inhibition" admixtures is better in the long term. Supplementary cementitious materials and "expansive agent with supplementary cementitious materials" admixtures delay the corrosion of sulfate mainly by improving the compactness and optimizing the pore size distribution, while "salt crystallization inhibition" admixtures not only optimize the pore structure of concrete to a certain extent, but also inhibit the formation of crystalline expansion products.