Performance Quantification of Interlayer Systems in Flexible Pavements Using Finite Element Analysis, Instrument Response, and Non Destructive Testing
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This study quantifies the benefits of two interlayer systems (steel reinforcing netting and a newly-designed geocomposite membrane) in different pavement applications. Steel reinforcing netting and geocomposite membrane have been installed at the Virginia Smart Road in four different sections. Ground penetrating radar (GPR) surveys and time domain reflectometer (TDR) validated the effectiveness of the geocomposite membrane in preventing water from infiltrating to the underneath layers. In pavement rehabilitation applications, based on finite element (FE) analysis, it was found that the geocomposite membrane would create a protective compressive field around the crack tip and separate the criticality of the stress field in the cracked area from the bottom of the overlay. However, if the crack passes through the interlayer, a faster propagation rate than in a typical pavement is expected. These results emphasize the importance of proper field installation. As to steel reinforcing netting, this study found that this interlayer system would be effective in new pavement systems in both the crack initiation and propagation phases when the cracks start at the bottom of the HMA layers. For the considered pavement structures, steel reinforcing netting was found effective to delay the initiation of the cracks. This delay depends on the stiffness of the hot-mix asphalt (HMA) layers, the reinforcing pattern, and the direction of the strain at the bottom of the HMA layers. After initiation of the crack, steel reinforcement contribute by delaying the rate of crack propagation to the pavement surface. In pavement rehabilitations, however, the crack is already well established in the existing pavement, and steel reinforcement contribution is expected from the time of installation. In this case, steel reinforcement will delay the initiation of the crack in the overlay, and reduce the rate of crack propagation afterwards. Two models, to predict the overlay service life against reflective cracking from existing HMA layers, were developed.
- Doctoral Dissertations