硫酸盐干湿循环作用对混凝土性能的影响

Effect of sulfate dry-wet circulation environment on concrete performance

为研究混凝土特性在硫酸盐干湿循环作用下的变化规律,采取硫酸盐环境下干湿循环的方法模拟西部硫酸盐环境,加速侵蚀混凝土。经过对两种强度混凝土试块加速侵蚀试验,研究了混凝土试块的表观特征、力学性能及质量随侵蚀的经时变化规律,讨论了混凝土强度等级对硫酸盐腐蚀程度的影响。结果表明:侵蚀初期,混凝土的质量、强度由于膨胀产物的填充和密实作用程现不同程度的增大;随侵蚀时间的不断延长,膨胀性产物的不断积累,混凝土出现劣化损伤,表现为质量、相对动弹性模量、强度的逐渐降低;硫酸盐干湿循环次数达150次之后,试件出现大量裂缝,角部混凝土大面积砂化、剥落,强度急剧下降。整个侵蚀过程中,强度等级较高的混凝土表现出较好的耐腐蚀性。

Sulfate dry-wet cycle accelerated erosion test to simulate the western sulfate environment.By accelerated corrosion test on different strength grade of concrete,concrete specimen is studied apparent characteristics,quality and mechanical properties with the changing rule of the erosion of time.The effect of concrete strength grade on the corrosion degree of sulfate was discussed.Results show that at the beginning of the erosion,due to the expansion of product fill compaction effect,makes the quality and strength of the concrete in different degree of increase.As the extension of erosion time,expand product accumulation,makes concrete damage,the strength and quality of concrete,and relative dynamic elastic modulus decreases gradually.After 150 days sulfate dry-wet circulation,specimen appear a large number of cracks,corner concrete large area of sand,peeling,the sharp decline in strength.The erosion process,the high strength grade of concrete shows good corrosion resistance.