Monitoring of Concrete Cylinders With and Without Steel Fibers Under Compression Using Piezo-Ceramic Smart Aggregates

An active sensing approach is employed to analyze the damage behavior of concrete cylinders under compression using smart aggregates. The smart aggregate sensor used in this study is developed by embedding a soldered water-proof piezo-ceramic patch inside stiff cement mortar. These smart aggregates are embedded at the desired locations in the concrete cylinders. A pair of smart aggregates is used with one acting as an actuator and other as a sensor. Wavelet packet analysis is used to analyze the recorded signals. Variation of cracking pattern observed at different levels of loading modifies the signal characteristics. Experimental investigations are carried out by testing eight concrete cylinders with and without steel fibers. The experimental result shows that the proposed method of using smart aggregates and evaluating damage index based on wavelet analysis is effective in monitoring the health of the concrete cylinders. Compression tests on steel fiber reinforced concrete cylinders indicate that the addition of fibers improves the ductility and post peak behavior under compression. Damage index variation shows that the steel fibers resist the crack propagation and results in improved performance.