Acoustic emission characteristics and damage characterization of opening-mode reflection cracking behavior of composite beams

In order to explore the cracking behavior of opening-mode reflective cracks in asphalt overlays, we carry out three-point bending test composite beams with cement overlay layer. We quantitatively evaluate damage based on acoustic emission (AE) characteristic parameters.Firstly, dynamically monitor process using AE technique, then, analyze horizontal strain through open source digital imaging software Ncorr,and finally, study beam by amplitude, ringing counts and energy. The results show that technology has a good recognition effect development micro-cracks macro-cracks overlay.According parameters, reflection can be divided into four stages: silent period, ascending period residual period. There is basically no signal period.In developing periods, increases rapidly, showing dense active, which consistent load curve, single-peak type characteristic.In approaching failure.The tends gentle.Opening-mode firstly spread along both sides joint, multi-fracture form, then one developes main crack continues extend vertically upward, secondary enters stagnation state.We propose method for characterizing evolution amount behaviorof composited beams. It provide reference analysis behavior.