A study of full-field debond behaviour and durability of CFRP-concrete composite beams by pulsed infrared thermography (IRT)

The methodologies and results of an empirical study on the full-field debonding behaviour of CFRP-strengthened concrete beam composites by pulsed infrared thermography are presented. The study made use of a combined destructive and nondestructive approach carried out simultaneously. From the destructive side, the specimens were destructively and progressively ruptured by a modified pull-out test, and from the nondestructive side, the extent of rupture was revealed and quantified by recording the time-lapsed and dissipated temperature/pixel distributions measured by pulsed infrared thermography (QIRT). The behaviour amongst the IRT-derived extent of rupture and load level were cross-plotted to derive an failure model, which becomes possible when IRT is used. The debonding of the CFRP-concrete composite started from an initial sub-critical (large load increment, small rupture) state to a critical (small load increment, large rupture) state after passing a yield point. The methodology was then repeated to evaluate the durability of 52 CFRP-concrete specimens after they were subjected to accelerated deterioration by moisture intrusion. These results substantiate the validity of the combined nondestructive and destructive approach to test and evaluate the full-field debond behaviour of the composite.