Prediction of the Remaining Fatigue Life of Flexible Pavements Using Laboratory and Field Correlations

Abstract

The main objective of this study was to develop comprehensive criteria to evaluate the remaining service life of existing roads as regards their field fatigue cracking characteristics using fracture mechanics principles and associated laboratory performance tests. Two base course layers were investigated for their residual fatigue lives: reference and modified stone mastic asphalt mixes. The two pavement systems’ material characteristics using the actual field cores were estimated in the laboratory, including moduli, fatigue relationships, and crack propagation parameters. Additionally, field measurements encompassed collection of falling weight deflectometer deflections, temperature variations, and traffic counts. Fatigue lives of the two base course layers were predicted using the developed laboratory-based fatigue and crack propagation parametric relationships during one climatic period. The modified structure presented significantly longer fatigue life than the reference mix. This was indicative of the findings that the laboratory procedure(s) based on asphalt mixture properties’ fracture and fatigue mechanics such as crack initiation, and propagation modeling and relationships are useful for evaluating the pavement mix’s performance in the field as well. Overall, laboratory tests provided reliable information regarding residual life predictions in case it is difficult to actually perform field measurements and estimate the residual life of a pavement system. The criteria developed in this study should serve as guidelines for agencies to comprehend and understand a substantial amount of information regarding asphalt materials’ fatigue characterization so that it can be implemented as one of the quality control tests to assess the pavement design life.