横向荷载裂缝对海洋浪溅区混凝土耐久性劣化影响

Influence of transverse load cracks on concrete durability degradation in ocean splash zone

采用人工预加载使试件产生裂缝并控制荷载裂缝宽度,研究了模拟海洋环境试验箱内混凝土表面横向荷载作用下裂缝宽度对浪溅区混凝土抗氯离子侵蚀的影响。试验结果表明:暴露56d和90d龄期且裂缝宽度不超过0.25mm时,混凝土试件同一深度处氯离子浓度随裂缝宽度增加而增大。相同暴露龄期时试件氯离子扩散系数随裂缝宽度增加而增大,裂缝宽度由0.10mm增加至0.15mm时试件氯离子扩散系数提高并不显著,进一步提高到0.25mm后,与裂缝宽度为0.10mm的试件相比氯离子扩散系数提高约3倍;暴露龄期90d纯水泥混凝土试件及复合掺合料混凝土试件的氯离子扩散系数均与裂缝宽度近似呈指数函数关系,胶凝材料组成体系仅影响函数中的固定值。

The influence of the crack width on the chloride erosion resistance of concrete in the wave splash zone under the action of transverse load on the concrete surface in the simulated marine environment test box was studied by using artificial preloading and controlling the load crack width. The test results show that the chloride concentration at the same depth of concrete specimen increases with the increase of the crack width when the crack width of 56 d and 90 d exposure age is less than 0.25 mm. At the same exposure age, the chloride diffusion coefficient of the specimen increases with the increase of crack width. When the crack width increases from 0.10 mm to 0.15 mm, the chloride diffusion coefficient of the specimen does not increase significantly. The chloride diffusion coefficient of the specimen with the crack width of 0.25 mm increases by about three times when compared with the chloride diffusion coefficient of the specimen with the crack width of 0.10 mm. The chloride diffusion coefficient of pure cement concrete specimen and composite admixture concrete specimen with 90 d exposure age is approximately exponential function of crack width, and the composition system of cementing material only affects the fixed value in the function.