基于超声回弹综合法的钢筋混凝土框架柱检测技术试验研究

Experimental Study on Testing Technology of the Reinforced Concrete Frame Column by Ultrasonic-Rebound Combined Method

为探明钢筋混凝土框架柱内部缺陷及混凝土强度,对其进行了超声回弹综合法检测,先进行超声波检测,提取了声时、声速和波幅进行数据处理和异常值分析,同时对混凝土强度进行了回弹检测。研究表明:(1)超声波检测对构件内部质量缺陷无法精准定位和准确描述,混凝土强度也只能通过声速推测,准确度较差,仅适用于定性分析。(2)声波遇孔洞和疏松部位时会产生反射和绕射,导致声时增长,且高频成分易被吸收,波幅明显降低。波速大小能反映混凝土的密实性,密实性越好,则波速越大。(3)回弹检测法的回弹值受混凝土表面强度的影响较大,无法探测混凝土内部质量缺陷及内部深处混凝土强度。(4)通过波速修正后的回弹值与取芯值更吻合,超声和回弹两者综合应用效果更佳。(5)超声回弹综合法和取芯法测得的混凝土强度分别为回弹检测值的87%和95%,超声回弹综合法检测混凝土强度的保证率最高,建议回弹值降低10%使用。

It has been carried out ultrasonic-rebound combined method to measure the internal defects and concrete strength of Reinforced concrete frame column,and extracted sound time,sound velocity,and wave amplitude for data processing and outlier analysis by ultrasonic testing first,simultaneously rebound concrete strength.Research shows that:(1)The ultrasonic test is unable to accurately locate and describe for the internal quality of defects,it is poor accuracy for predicting concrete strength based on sound velocity,only applicable for qualitative analysis.(2)Sound waves will reflect and diffract when encountering holes and loose areas,and increase sound wave operation time,and wave amplitude is significantly reduced because of high-frequency components absorbed.The wave velocity reflects the compactness of concrete,and the better the compactness with the higher the wave velocity.(3)The concrete rebounding value is greatly affected by the surface strength,a rebound method is unable to measure the concrete strength in internal depths and describe for the internal quality of defects.(4)It is more consistent with the core value when the rebounding value is corrected by wave velocity,and ultrasonic-rebound combined method has a better effect.(5)The concrete strength values measured by the ultrasonic-rebound combined method and the core sampling method are 87%and 95%of the rebounding value,it is the highest assurance rate of the concrete strength by the ultrasonic-Rebound combined method,It is suggested that the concrete rebounding value should reduce by 10%before use.