Fatigue-life prediction of full-scale concrete pavement overlay over flexible pavement: Super-accelerated pavement testing application
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Thin concrete pavement overlay placed on the top of flexible pavements is referred to as a thin whitetopping (TWT) pavement, which is one of the rehabilitation treatments for deteriorated flexible pavements. The primary goal of this study is to evaluate the fatigue performance of full-scale TWT pavement due to repeated traffic loading. Super-accelerated pavement (SAP) tests on full-scale TWT concrete slabs were performed under static and constant cyclic loading. The stationary dynamic deflectometer (SDD) (a truck-mounted SAP testing device) was used to statically and dynamically load the TWT slabs. To monitor the response of the TWT slabs, accelerometers and linear variable differential transformers (LVDTs) were installed and the dynamic displacements of slabs were recorded during the entire testing period. The test results show that the tested slabs have dynamic displacement peaks around the number of load repetitions corresponding to the first visible cracks. The dynamic displacement increased at a higher rate after the occurrences of the first visible crack. In addition, the tested slabs showed a stress redistribution phenomenon during the crack propagation. The concepts of the stress level and equivalent fatigue life were used to eliminate, in part, influences of other factors (that is, the water-cement ratio [w/c] and aggregate type and gradation) and correct the effect of different stress ratios, respectively. The S-N curve developed from this study was very close to Thompson and Barenburg's S-N curve after the application of the equivalent fatigue-life concept. Copyright 2013, American Concrete Institute. All rights reserved.