疲劳荷载与硫酸盐腐蚀耦合作用下道路水泥混凝土劣化研究

Research on the Damage of Road Concrete Subjected to the Coupling Effect of Fatigue Load and Sulfate Corrosion

利用自研的疲劳腐蚀试验装置,开展了应力水平为0.3、0.5、0.7的疲劳荷载与浓度为5%、10%的硫酸盐溶液耦合条件下道路水泥混凝土的损伤试验。通过测试不同疲劳侵蚀龄期道路混凝土的弯拉强度及相对动弹性模量,揭示疲劳荷载与硫酸盐耦合作用下道路混凝土的劣化过程。结果表明:硫酸盐对道路混凝土的腐蚀损伤分为前期的填充密实阶段及后期的膨胀开裂阶段,硫酸盐浓度越大对水泥混凝土性能腐蚀越严重;疲劳荷载作用并没有改变硫酸盐的腐蚀劣化机理,但促进了硫酸盐的腐蚀作用,且疲劳荷载应力水平越大,荷载对硫酸盐腐蚀的促进作用越显著;耦合作用下道路混凝土弯拉强度的损失与硫酸盐浓度、疲劳荷载水平及侵蚀龄期之间存在很好的线性关系。

In this paper, the damage tests of road concrete have been done by using self-developed fatigue corrosion test apparatus under the coupling effect of different fatigue load levels of 0.3, 0.5, 0.7 and different sulfate concentration of 5% and 10%. Though testing the flexural strength and the relative dynamic elastic modulus of road concrete under different fatigue erosion age, the degradation process of road concrete under the coupling effect of fatigue load and sulfate coupling are revealed. The results show that the corrosion damage process of sulfate to road concrete is divided into two stages, that is the early filling compaction and expansion cracking in the late. The greater the sulfate concentration, the more serious the corrosion of road concrete performance. Fatigue load does not change the mechanism of sulfate corrosion, but promotes the sulfate corrosion damage, and the greater the fatigue load stress level, the more significant promote effect of sulfate corrosion. There is a good linear relationship between the flexural strength loss of road concrete and sulfate concentration, fatigue load level and the erosion ages under the coupling effect.