Monitoring of Grouting Compactness in a Post-Tensioning Curve Tendon Duct Using Piezoceramic Transducers

In order to further understand the characteristics of longitudinal grouting compactness, this paper develops a stress wave based active sensing approach using piezoceramic transducers for monitoring the longitudinal grouting compactness of the curve tendon ducts. Experimental results show that in the no grouting, 50% grouting, 75% grouting, and 90% grouting conditions, the sensors cannot receive any stress wave. Only when the actuator and the transducers are grouted fully, the transducers can receive the stress wave propagated by the actuator. The wavelet packet-based energy analysis was adopted to compute the total signal energy received by PZT sensors in this research. With the change of the grouting compactness in the posttensioned tendon curve duct, the energy received by the sensor closer to the actuator changes more rapidly than that received by the sensor farther from the actuator. This is mainly due to the fact that these sensors are located in different longitudinal positions, which leads to their different degree of grouting compactness in the same time period. This paper shows that the grouting quality can be effectively evaluated by analyzing the difference between the signals received by the transducers in the curve tendon duct. So, the proposed method has potentials to be utilized to monitor the grouting quality of the curve tendon ducts.