扰动对混凝土抗氯离子渗透性能的影响研究

利用改造后的击顶式振筛机提供三维扰动,通过线切割内部偏心顶轴,使竖向振幅接近南京长江大桥公路桥桥面的实际振幅;配制C30、C50普通混凝土和掺抗扰动剂的C50混凝土,设计7种扰动制度,研究了各扰动制度对混凝土抗氯离子渗透性能(RCM)的影响。研究结果表明:C30混凝土终凝前1 h受扰动,上部试块RCM值增幅最大,增幅为70.4%;C50混凝土终凝时受扰动,上部试块RCM值增幅最大,增幅为95%;该阶段混凝土的可塑性基本消失,受扰动后局部密实度降低,RCM值增大明显。掺入抗扰动剂可以实现混凝土“初期增稠”与“早期增强”,大幅提升普通混凝土的整体抗扰动性能,相比于自身未扰动组,受各扰动制度后RCM值几乎没有降低。

Research on the Chloride Migration Coefficient Evolution of Concrete After Being Disturbed

Using the modified test-sieving machine to provide three-dimensional disturbance,the vibration amplitudes were close to the actual amplitudes of the road bridge deck of Nanjing Yangtze river bridge by cutting the internal eccentric top shaft.Seven disturbance systems were designed to study the influence on rapid chloride ions migration coefficient(RCM)of C30、C50 ordinary concrete and C50 anti-disturbance concrete.The study results show that when C30 ordinary concrete is disturbed at 1 h before the final setting,the RCM value of upper block increases the most with an increase by 70.4%.When C50 ordinary concrete is disturbed at the final setting,the RCM value of the upper block increases the most,by 95%.At these stage,the plasticity of concrete basically disappears,leading to a decrease in compactness and a significant increase in RCM value.Adding disturbance resistance agent,the concrete can achieve"initial thickening"and"early strengthening",and improve the overall anti-disturbance performance.The RCM values before and after disturbance are almost the same.