【摘要】 目的研究碳纤维加固混凝土粘贴质量,确定此类结构超声检测方法和适用范围.方法通过超声对粘贴碳纤维的混凝土试件进行检测,通过测量声时、声速和首波幅值等参数,提前设置粘贴缺陷,以粘贴密实部位检测结果作为基准,比较声速和波形的变化,以此作为缺陷评价的依据:当缺陷部位声速明显下降,波形为缺陷波,可判断为粘贴缺陷部位.结果超声检测缺陷部位及圆形、方形缺陷部位的声速比密实部位的声速均小约0.23 km/s;检测碳纤维粘贴缺陷的最小面积2 cm2;检测有钢筋试件声速比无钢筋试件声速约大0.34 km/s;超声检测二层、三层碳纤维缺陷部位声速分别低于二层、三层密实部位声速0.37 km/s、1.40 km/s.结论超声法可有效检测碳纤维加固混凝土缺陷位置、大小等粘贴质量问题;检测结果无边缘效应;确定检测精度的最小面积;混凝土振捣不密实的试件,声速明显下降;碳纤维层数越多,声速下降越明显.更多还原

【Abstract】 The paper was proposed to investigate the sticking quality and determine the ultrasonic testing method and the application range of the structure. Ultrasonic was used to test concrete specimens of sticking carbon fiber based on sound-timing,sound-velocity,first wave amplitude and other parameters. The sticking defects was set up in advance,and taking the test results of sticking compacted parts as a benchmark,the changes in sound velocity and waveform were compared and regarded as the basis for the evaluation of defects: when sound velocity of the defective parts decreases significantly,the waveform presents the defective wave,which could be judged as the stick-ing defective parts. The results showed the sound velocities of the ultrasonic testing,circular and square defective parts as well as the dense parts were all less than 0. 23 km/s; the minimum area of paste defects of ultrasonic testing carbon fibers was 2 cm2; the sound velocity of the ultrasonic testing with reinforced specimens was about 0. 34 km/s faster than that of the ultrasonic testing without reinforced specimens; the sound velocities of the defective parts of the second-layer and the third-layer carbon fibers of the ultrasonic testing were respectively 0. 37 km/s and 1. 40 km/s low-er than those of the dense parts. Ultrasonic method can effectively detect the defective location,size and other sticking quality problems of reinforced concrete of carbon fibre without fringe effect,and the minimum area of detection accuracy was determined when sound velocity of uncompacted concrete-vibration specimens decreased significantly,and the sound velocity decreased more obviously with more carbon fibers layers.更多还原