锈蚀对钢筋混凝土冲击回波特性的影响试验研究

Influence of Reinforced Concrete Corrosion on Impact-Echo Characteristics

通过室内试验,采用弹性波检测的方法研究锈蚀对钢筋混凝土冲击回波的影响规律,以此来确定冲击弹性波波速、加速度频谱与锈蚀程度的关系,建立了锈蚀时间与加速度频谱面积的关系曲线。试验结论表明,在尺寸为100 mm×100 mm×400 mm的钢筋混凝土试件中,弹性波波速随着锈蚀时间的增长而减小,当锈蚀时间在96 h时,波速平均下降31%;加速度频谱面积随着锈蚀时间的增长而减小,当锈蚀时间在96 h时,频谱面积平均下降57%;在尺寸为100 mm×200 mm×1850 mm的钢筋混凝土试件中,弹性波波速随着锈蚀时间的增长而减小,在锈蚀时间在72 h时,波速平均下降8%以上;加速度频谱面积平均下降74%。通过理论分析解释了上述试验现象,并提出了一种采用冲击回波特性来测量钢筋锈蚀的新方法,为土木水利工程混凝土无损检测提供参考。

In order to determine the shock wave velocity and the relationship between the acceleration spectrum and the degree of corrosion,the influence of corrosion on the impact echo of reinforce concreteis studied using the elastic wave method.The relationship curve between the corrosion time and the descending rate of acceleration spectrum areais also established.The experimental result shows that in the 100 mm×100 mm×400 mm reinforced concrete specimen,the elastic wave velocity decreases as the increase of the corrosion time.When the corrosion time at 96 h,the average wave velocity decreases by 31%.The acceleration spectrum area decreases with the increases of corrosion time;when the corrosion time was 96 h,the corrosion area decreased by 57%.In the 100 mm×200 mm×1 850 mm reinforced concrete specimen,the elastic wave velocity decreased with the increase of the corrosion time.At 72 h,the average velocity of the acceleration spectrum decreased by more than 8% and the acceleration spectrum area decreased by 74%.A new method is proposed to measure the corrosion of reinforcement by means of impact echo characteristics through theoretical analysis,which can provide reference for nondestructive testing of concrete in civil engineering.