模拟地下水压力作用下混凝土硫酸盐腐蚀行为研究

针对地下混凝土结构的耐久性问题,利用室内模拟试验技术,研究不同地下水静水压力(0、0.1和0.2 MPa)和粉煤灰掺量(10%、25%和40%)对混凝土受硫酸盐腐蚀的影响,测定了混凝土腐蚀60 d后的腐蚀深度和力学性能指标(抗压强度和动弹性模量)。试验结果表明,混凝土的硫酸盐腐蚀深度随粉煤灰掺量的增加而线性降低;随地下水压力的增加近似呈线性增加。混凝土的抗压强度和动弹性模量随粉煤灰掺量的增加而降低,随地下水压力的增加而略有提高。此外,对混凝土抗压强度和超声波速的相关性进行分析,结果表明粉煤灰和水压力对抗压强度与超声波速关系的影响不明显;通过回归分析建立了硫酸盐腐蚀后混凝土抗压强度和超声波速的指数关系模型。

Corrosion Behaviors of Concrete Exposed to Sulfate Attack with Simulated Groundwater Pressure

This paper is aimed at the durability of underground concrete structure,and the influence of water pressure (0,0.1 and 0.2 MPa) and fly ash content (10%,25% and 40%) on sulfate corrosion of concrete which were studied by means of laboratory simulation test technique.In the experiment,the sulfate corrosion depth and mechanical properties (compression strength and dynamic elastic modulus) of concrete after 60 days of corrosion were measured.The results show that the sulfate corrosion depth of concrete decreases linearly with the increase of fly ash content,and increases linearly with the increase of water pressure.The compression strength and dynamic elastic modulus of concrete decrease with the increase of fly ash content,and slightly increase with the increase of water pressure.In addition,the relationship between the compression strength and ultrasonic pulse velocity of concrete was analyzed.The result indicates that the influences of fly ash content and water pressure are not obvious.Based on the regression analysis,an exponential model between the compression strength and ultrasonic pulse velocity of concrete exposed to sulfate attack is established.