美国推出了一种混凝土湿度计。它为建筑工程技术提供了一种混凝土建筑物湿度新的检查方法。　　这种仪器是根据电子湿度计制成的。工作时，将一组平行的低频信号发射进被测物的表面，通过这组信号就可得出混凝土内层水分的含量情况，所测深度在混凝土表面以下1000mm左右。使用 The United States introduced a concrete hygrometer. It provides a new test method for building construction technology for concrete building humidity. This instrument is made according to an electronic hygrometer. Work, a group of parallel low-frequency signals emitted into the surface of the measured object, through this set of signals can be obtained within the concrete inner moisture content, the measured depth below the concrete surface about 1000mm. use