不同环境条件下混凝土构件氯离子侵蚀试验

Chloride ion erosion experiment of concrete members under different environmental conditions

摘要:

为研究不同环境条件下混凝土构件氯离子侵蚀劣化规律，开展弯拉应力构件的氯离子浸泡侵蚀试验和无应力构件的盐雾侵蚀试验.基于氯离子质量分数、构件弯拉强度及弯拉应变等测试结果，研究了侵蚀时间、环境温度、应力水平、环境氯离子质量分数及侵蚀方式等因素对氯离子扩散特征和构件抗弯性能的影响.试验结果表明：浸泡环境中混凝土内部氯离子质量分数较盐雾环境高；试件内部氯离子质量分数随腐蚀时间、环境温度、环境氯离子质量分数及应力水平的增大而增大；氯离子扩散系数随应力水平和环境温度的提高而增大；在较低应力水平、较低环境温度和较短的侵蚀时间内，混凝土构件极限弯拉强度有小幅度上升趋势，然后随侵蚀时间的增长而衰减；混凝土构件的极限弯拉应变随各影响因素的增大而降低.研究结果可为钢筋混凝土构件在氯盐侵蚀环境下的耐久性评估及设计提供依据，具有一定工程实际意义.

Abstract:

To study the erosion degradation rule of the concrete member under different chloride ion erosion conditions, the chloride ion immersion tests for the flexural-tensile concrete member and salt spray tests for non-stress concrete member were carried out. Based on the test results of chloride mass fraction, flexural-tensile strength and flexural-tensile strain of concrete member, the effects of erosion time, environmental temperature, stress level, environmental chloride ion mass fraction and erosion pattern on the diffusion rule of chloride ion and flexural-tensile strength of concrete members were studied. The results show that, the chloride ion mass fraction in soaking environment is higher than that in salt spray environment; the chloride ion mass fraction increases with the erosion time, environmental temperature, chloride ion concentration and stress level; the diffusion coefficient increases with the increasing of the stress level and temperature; under the condition of lower stress level, lower temperature and shorter erosion time, the ultimate flexural-tensile strength of concrete members has a slight upward trend, and then it decreases with erosion time; the ultimate flexural-tensile strain of concrete members decreases while the influence factors increase. The results provide a theoretical base for the durability assessment and design for concrete member under chloride ion erosion environmental and have some practical values.