硫酸盐和干湿循环作用下早龄期混凝土劣化性能研究

Deterioration performance of early age concrete under the attack of sulfateion and dry-wet cycles

针对硫酸盐侵蚀和干湿循环共同作用下早龄期混凝土试件进行了压汞(MIP)试验、超声波声速测试和单轴压缩试验,测定了不同干湿循环次数下混凝土试件的孔隙率、超声波声速值和抗压强度值随干湿循环次数的经时变化规律。研究结果发现:随干湿循环次数的增加,混凝土的孔隙率经历了一个先减小后增大的过程,而超声波声速值和抗压强度值则经历了一个先增大后减小的过程。上述结果从混凝土内部孔隙结构密实性的变化角度解释了硫酸盐和干湿循环作用对宏观性能作用的影响机制。

The mercury(MIP)test,ultrasonic velocity test and uniaxial compression test of early age concrete specimens under the combine of sulfate ion erosion and dry-wet cycle were carried out.The laws of the porosity,ultrasonic velocity value and compressive strength of concrete specimens were measured over different dry-wet cycles.The results show that the porosity of concrete has experienced a process of decreasing and then increasing with the increase of the number of dry-wet cycles,while the ultrasonic velocity and the compressive strength have experienced a process that increases first and then decreases.This indicates that the change of density of pore structure in concrete results into the change of ultrasonic velocity and compressive strength.