Nondestructive Evaluation Advancements for Damage Detection in Concrete

Abstract

While concrete is the most widely used civil engineering material, damage detection and progression in concrete structures have still proven to be difficult to address, especially when only one-sided access is available. New technological advances in nondestructive testing technology have created the opportunity to better utilize ultrasonic waves to aid in this damage detection process. However, interpretation of the signal data is a challenging task which often requires subjective assessments. This thesis addresses these limitations via the utilization of ultrasonic array technology for nondestructive damage detection purposes. The ultrasonic shear velocity array system used for this research is particularly advantageous because it can obtain measurements on virtually any concrete specimen, from columns and beams to concrete pavements, and provides a wealth of data from a single measurement. Novel signal interpretation methods were developed for several important concrete applications. Detection of load-induced damage in laboratory beams and a full-scale reinforced concrete column, as well as standard life-cycle damage in concrete pavements caused by freeze thaw or alkali-silica reaction degradation were considered. These investigations culminated in the development of successful and efficient quantitative damage detection methods. Finally, the development and refinement of a simulation program allowed for verification of the experimental investigation and a greater understanding of signal results.