Title: Structural Characteristics of Aged Asphalt Concrete Pavements
Abstract: When an asphalt concrete (AC) pavement is in service, it requires periodic resurfacing and rehabilitation to provide acceptable performance. The most popular resurfacing method is an asphalt overlay over the existing roadway. In the design of asphalt overlays for structural capacity increase, the thickness is related to the structural capacity of the existing pavement. As the layers are overlaid, their structural characteristics change due to aging of asphalt. This study examined structural characteristics of six AC pavement test sections in Kansas using two different test methods: Indirect Tension (IDT) Resilient Modulus and Direct Tension Fatigue tests. The results were analyzed to determine how the modulus of an AC pavement layer changes over time. The results indicate that as the AC pavement ages, its modulus decreases due to pavement deterioration, especially stripping. Two test sections that showed little signs of stripping had a minimal reduction or even an increase in AC moduli. Thus stripping issue needs to be addressed to ensure longevity of AC pavements. Fatigue test results show that older pavement layers have a higher propensity for fatigue failure than the newer layers. However, some older pavement layers showed excellent fatigue life. For most projects, initial strain, air voids, and asphalt content significantly affected the fatigue life of the aged AC mixtures. These factors indicate both structural and mixture designs as well as compaction are essential factors in determining AC fatigue life. Fatigue results correlated well with the condition of the cores as assessed by visual observation. For overlays, it is highly recommended that the existing pavement cores be thoroughly studied or any nondestructive method such as, Ground Penetrating Radar (GPR) survey be done on the existing pavement to identify layers that are distressed.
Publication Year: 2014
Publication Date: 2014-01-01
Language: en
Type: article
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Cited By Count: 1
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