A True Dynamic Method for Nondestructive Testing of Rigid Pavements with Overlays

Abstract

This study presents a new method for dynamically evaluating rigid pavements with overlays, utilizing a vibratory nondestructive testing device, a dynamic signal analyzer, and a microcomputer. The method employs a FORTRAN program, GREEN-MA, which calculates dynamic structural responses of layered systems to harmonic loads using Green's functions. A modified backcalculation algorithm, COMDEF, incorporates dynamic deflections to quickly and accurately perform true dynamic backcalculations. Dynamic theory enhances data utilization from a single test, expanding the dataset to include phase shifts between sensors. This allows for the creation of a "real time" deflection basin, offering a snapshot of the pavement's deflection at a specific moment. The method addresses the challenges posed by evaluating pavements overlain with asphaltic concrete, for which traditional evaluation methods may lead to underdesign or overdesign due to the invisibility of the underlying rigid layer condition. The proposed dynamic evaluation method significantly improves the assessment of pavement structural condition, providing more reliable data for estimating remaining life and allowable loads. It demonstrates the importance of true dynamic analysis over traditional quasi-static approaches, particularly in handling the complexities of pavements with overlays. The study underscores the benefits of incorporating phase data and advances in signal analysis technology to enhance the accuracy and utility of nondestructive pavement testing. (Abstract generated by AI tool ChatGPT 4)