正在俄亥俄河上施工的一座混凝土斜拉桥,其塔架的混凝土强度要求大于420kg/cm~2,且不能有孔隙,这样,就要在混凝土浇注期间进行检测,以确保混凝土的均匀性和密实性。检测时,采用了一种新的非破损检验法,利用内部振捣器在塑性混凝土中发射声信号,由模板上的声传感器接收信号,并传给示波器。从示波器上信号的频率和振幅的变化就可以求得塑性混凝土的密度指数。试验先在大型试块上进行,以校准设备并鉴 A concrete cable-stayed bridge that is being constructed on the Ohio River requires a tower concrete strength of more than 420 kg/cm2 and no porosity. Therefore, it is necessary to inspect the concrete during pouring to ensure evenness and compactness of the concrete. . During the test, a new non-destructive inspection method was used. Internal vibrators were used to emit acoustic signals in plastic concrete. The acoustic sensors on the templates received signals and transmitted them to the oscilloscope. The density index of plastic concrete can be obtained from the change of the frequency and amplitude of the signal on the oscilloscope. The test is first performed on a large test block to calibrate the equipment.