Water content and its effect on ultrasound propagation in concrete - the possibility of NDE
Water content and its effect on ultrasound propagation in concrete - the possibility of NDE
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DOI：
10.1016/s0041-624x(99)00158-4
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发表时间：
2000-03-01
期刊：
影响因子：
4.2
通讯作者：
Masuzawa, N
中科院分区：
文献类型：
--
作者：
Ohdaira, E;Masuzawa, N
众所周知，含水量或湿度影响混凝土的强度。为了探讨混凝土超声无损检测的可能性，从混凝土中含水量与超声传播的关系出发，测量了混凝土中超声传播的声速和频率分量随含水量的变化，并对常用材料混凝土试件进行了基础研究。测试件尺寸为直径10 cm和长度20 cm。将试样浸入水中约50天以使其饱和。为了测量不同水含量的影响，将测试件放入干燥室中以改变测量之间的水量。重复该过程直到混凝土完全干燥并且重量不再改变。水含量定义为相对于完全干燥状态的重量百分比。采用脉冲透射法，测量了频率范围为20 ~ 100 kHz的超声波传播与含水量的关系。根据含水量的不同，声速从3000 m/s逐渐变化到4500 m/s。最大透射频率也取决于该频率范围内的含水量。认为混凝土强度的超声无损检测是可行的。(C)2000 Elsevier Science B. V.保留所有权利。
It is known that water content or moisture affects the strength of concrete. The purpose of this study is to examine the possibility of the NDE of concrete from a knowledge of the relationship between water content and ultrasonic propagation in concrete.The results of measurements made on the ultrasound velocity and the frequency component on ultrasonic propagation as a function of the water content in concrete are reported.Test pieces of concrete made from common materials were made for the fundamental studies. The test piece dimensions were 10 cm in diameter and 20 cm in length. Test pieces were immersed in water for about 50 days to saturate them. To measure the effect of different water contents, test pieces were put in a drying chamber to change the amount of water between measurements. This procedure was repeated until the concrete was completely dried and the weight no longer changed. Water contents were defined as weight percentage to full dried state. Thus water content could be changed from 8% to 0%.Using the pulse transmission method, ultrasonic propagation in the frequency range 20 to 100 kHz was measured as a function of water content. The sound velocity varied gradually from 3000 m/s to 4500 m/s according to the water content. The frequency of maximum transmission also depended on the water content in this frequency range. It is considered that the ultrasonic NDE of concrete strength is feasible. (C) 2000 Elsevier Science B.V. All rights reserved.