Evaluation of condition on replacing repaired concrete based on NDT and the Mahalanobis–Taguchi system

Abstract

In Japan, much infrastructure has been constructed over the past 50 years, and maintenance of such infrastructure is important. Repairing and retrofitting of deteriorated concrete members has become a common place. Meanwhile, re-deterioration of repaired concrete members has become of concern. To prevent re-deterioration of the repaired concrete members, it is important to evaluate the quality and condition of repair, in addition to the use of NDE. Therefore, to evaluate the condition of replacing repaired concrete specimens, an ultrasonic test, impact-echo test, and impact test for measuring mechanical impedance were applied. In addition, data of these NDT are integrated by the Mahalanobis–Taguchi system (MT system). The MT system is an information processing system for pattern recognition advocated by quality engineering. From the results, it is clarified that the Mahalanobis distance calculated by the MT method could successfully evaluate the conditions of replacing repaired specimens.