混凝土冻融试验和表面剥落的无损检测

Accelerated Freeze-thaw Test of Concrete and Nondestructive Testing of Surface Spalling

造成混凝土严重损坏和使用寿命显著缩短的主要原因是其体内孔隙中水或盐溶液的冻结。目前大多数冻融加速试验测量通过称重混凝土表面剥落的部分,提出了基于使用的补充程序应变计和超声波脉冲速度(UPV)测量混凝土的冻融劣化方法。这些无损检测(NDT)程序适用于两种类型在混凝土中,一种易受冻融损伤,另一种不易受冻融损伤。由于湿度和温度是影响最大的参数,故在样品中加入了用于测量温湿度的嵌入式传感器。结果表明:标度与无损检测获得的测量值之间有很好的相关性,显示出无损检测可以用于损坏前进行检测和连续测量。

The main reason for serious damage and obviously shortened service life of concrete is the freezing of water or salt solution in the pores of concrete.At present,most of the freeze-thaw accelerated tests measure the spalling of concrete surface by weighing the part.In this paper,a method based on the supplementary program strain gauge and ultrasonic pulse velocity(UPV)is proposed to measure the freeze-thaw deterioration of concrete.These nondestructive testing(NDT)procedures are applicable to two types of concrete,one susceptible to freeze-thaw damage and the other not susceptible to freeze-thaw damage.Because humidity and temperature are the most important parameters,the embedded sensor is added to the sample to measure the temperature and humidity.The results show that there is a good correlation between the scale and the measured values of nondestructive testing,which shows that nondestructive testing can be used for detection and continuous measurement before damage.