Study of the asphalt pavement damage through nondestructive testing on overweight truck routes

Many highway facilities experience deterioration due to high traffic volumes and a service life that has been extended beyond facility design life. The 75th and 76th Texas Legislatures passed bills allowing trucks of gross vehicle weights (GVW) up to 125,000 lbs to routinely use a route in south Texas. Since the Texas Department of Transportation (Tx DOT) is concerned about the impact of overweight truck traffic (OTT) on its highways, there is a need to establish how the impact of this OTT on Texas roads will be incorporated into a long-term strategy for identifying and developing solutions to this problem. In this study was investigated the effects of overweight truck traffic on a permitted truck route in the city of Brownsville. This route proceeds from the Veterans International Bridge to the Port of Brownsville via US77, SH4 and SH48 (SH 4/48). The objective of this study is to establish the impact of this heavy loads on the pavement structure through nondestructive testing. The problem increased in severity due to the increased flow of trade from the Port of Brownsville to Mexico, thus the expecting deterioration on the routes is mainly along the southbound lanes K6 and K7. To accomplish this objective was conducted two nondestuctive testing as GPR and FWD test. The K6 and K7 lanes were divided on 56 and 50 FWD stations, respectively. In addition, it was taken AC core samples to be tested with frequency sweep test. All these information assisted to analyze: the route profile, layers thickness, static and dynamic backcalculated AC moduli, dynamic (complex) modulus from laboratory testing, creep compliance parameters from the laboratory testing and dynamic analysis, and corrected AC moduli by temperature using three differents equations. In addition, it was analyzed the effect of the cumulative 18-kip Equivalent Single Axle (ESAL) in both K6 and K7 lanes. The results from the first analysis provide evidence of damage in the K6 lane; however, more significant results were found in the traffic analysis. This study confirms that because of greater amount of truck traffic (OTT) travels on K6 it has lesser AC moduli than the K7 lane.