Experimental study on loading rate and notch-to-depth ratio effects on flexural performance of self-compacting concrete with acoustic emission and digital image correlation technologies

As no extra vibration is needed in the casting procedure of self-compacting concrete for its excellent workability under its own dead weight, the material can be applied to construction projects where vibrations are hard to perform. To better utilize self-compacting concrete in practical engineering, it is essential to conduct an in-depth study on its fracture performance. In this study, three-point bending tests on notched self-compacting concrete beams were performed considering different loading rates and notch-to-depth ratios as variables. Acoustic emission technique and digital image correlation method were utilized to collect acoustic emission signals generated in the loading procedure and monitor crack propagation in the fracture process zone, respectively. Results show that theb-value from acoustic emission analysis can be divided into three stages and the variation range increases as the notch-to-depth ratio increases. Based on clustering analysis, three cluster groups can be obtained, and it is found that the ratio of the first cluster group decreases while that of the third cluster group increases when notch-to-depth ratio increases. With the aid of digital image correlation technique, effective crack length and horizontal crack opening displacement can be recorded and it is observed that crack tip opening displacement decreases as the notch-to-depth ratio increases.

Automated summary

Self-compacting concrete has excellent workability under its own dead weight, making it suitable for construction projects where vibrations are difficult. This study conducted three-point bending tests on notched self-compacting concrete beams with varying loading rates and notch-to-depth ratios. Acoustic emission analysis and digital image correlation techniques were used to study crack propagation behavior and fracture performance.