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The objective of the study was to evaluate the sensitivity of different input variables on the flexible pavement design thickness of high-speed, high-traffic routes in South Carolina using the Mechanistic-Empirical Pavement Design Guide (MEPDG) by means of the AASHTOware Pavement ME design software. A combination of MEPDG input levels (Levels 1, 2, and 3) were used for pavement analysis based on the availability of data. The variables considered in this investigation included two-way average annual daily truck traffic (AADTT), asphalt mix type, climate station, subgrade type and resilient modulus, and aggregate base thickness. This study mainly focused on the bottom-up fatigue cracking, and individual pavement designs were evaluated to determine the asphalt concrete (AC) thickness for which the total bottom-up cracking was equal to 2% lane area after a 20-year design period. The results indicated that the asphalt mix type did not have significant impact on the pavement thickness. One of the five climate stations evaluated resulted in significantly thicker pavements than the others. Subgrade type, as well as resilient modulus, had a significant effect on the pavement thickness. Finally, pavements were more sensitive to total truck traffic changes at lower AADTT values and then became somewhat less sensitive when exposed to the highest levels of traffic. The results of this study could potentially be used to develop a preliminary asphalt thickness design catalog for interstate routes in South Carolina.


International Journal of Pavement Research and Technology


Civil and Environmental Engineering