Comparative Overview of Non-Destructive Testing of Asphalt Concrete

Mix segregation, in-place compaction, smoothness, temperature segregation, layer thickness, layer bond, and pavement modulus are characteristics that govern quality pavement construction. Available technologies that measure one or more of these characteristics are identified for unique attributes of test measure, test portability, complexity, test time, environmental limitations, reliability, approved test protocols, training, and cost. A quantitative ranking system determines the most appropriate technologies for quality-assurance measurement. A case study selection is demonstrated uniquely for one agency to measure predefined critical characteristics of in-place compaction, thermal segregation, and modulus using three technologies: infrared thermography, ground penetrating radar, and the portable seismic pavement analyzer. Results from field testing reveal additional aspects of pavement quality measurement beyond traditional density and smoothness measurements. Nondestructive testing provides ideal means to test pavement structure in a rapid and convenient manner. In last few years, significant development has taken place in this field. This paper, presents some of the major conventional as well as emerging nondestructive evaluation methods for in situ structural assessment of asphalt pavements. Discussion of methods is primarily directed towards the estimation of layer moduli and thickness values which are direct indicators of the structural strength of pavement. Estimation of density, moisture content, etc. has not been emphasized in this paper