Interlayer Bond Evaluation in the Flexible Pavement Structures Using a Nondestructive Testing Method

Abstract

The paper proposes a new approach to the bond condition evaluation of flexible pavement structural courses using a nondestructive testing method. It provides numerical modeling results of the effect of the bond loss between flexible pavement components on the form of acceleration frequency-response characteristics on the pavement surface under impulse loading. It has been determined that providing a full bond between all components of the flexible pavement structure, there is one distinct frequency peak magnitude on the acceleration frequency-response characteristics. With the interlayer bond loss between the asphalt concrete layers and the pavement base course on the acceleration frequency- response characteristics of the flexible pavement surface, recorded at 0.75-1.25 m from the loading point there are two frequency peak magnitudes within 0-350Hz and 350-500Hz. With the interlayer bond loss between all components of the flexible pavement structure on the acceleration frequency-response characteristics recorded at 0.25 - 2.5 m, there is a number of frequency peak magnitudes located in the frequency domains of 0-200; 200 - 350, 350 - 500Hz. The adequacy of the numerical modeling results is proved by good coherence between the forms of acceleration frequency-response characteristics measured with the use of the analytical model of the dynamic strain - stress condition and frequency-response characteristics recorded on the flexible pavement surface in different operation field conditions. There have been determined opportunities for the development of the proposed approach which are related to the improvement of the methods and techniques of the pavement evaluation in the frequency domain under dynamic loading.