Comparison of acoustic emission b-values with strains in reinforced concrete beams for damage evaluation

摘要

Reinforced concrete beam specimens were tested under incremental cyclic loading and the acoustic emission released during the fracture process of concrete was used to compute the acoustic emission-based b-values. The b-value based on Gutenberg-Richter formula was calculated from the frequency-amplitude plots of acoustic emission released. The strains in steel and concrete were compared with the corresponding fa-value at various stages of loading to assess damage occurred in reinforced concrete beam specimens. The code of practice IS 456:2000 has defined limits for serviceability and collapse. A brief review of the application of acoustic emission testing to concrete structures is given. It is observed that the fa-value reaches its minimum near the peak load and reaches maximum during micro cracking while it tends to decrease when micro cracks coalesce and start forming major and visible cracks.