Sensitivity of thermal properties of pavement materials using mechanistic-empirical pavement design guide

摘要

Pavement design procedures available in the literature do not fully take advantage of mechanistic design concepts, and as a result, heavily rely on empirical approaches. However, reliance on empirical solutions can be reduced by introducing mechanistic-empirical methods, now adopted in the newly released Mechanistic-Empirical Pavement Design Guide (MEPDG). Thermal properties like, coefficient of thermal expansion (CTE), thermal conductivity, heat capacity, surface shortwave absorptivity, ultimate shrinkage strain, mix coefficient of thermal contraction, which control the flow of heat through pavements constitute the primary inputs to MEPDG.;A study was undertaken to compare the sensitivity of thermal input parameters on the performance of concrete and flexible pavements using MEPDG Version 1.0. Effect of climate on the pavement performance was also evaluated. Results from all the simulations showed that almost all of the cases produce reasonable values for transverse cracking, faulting, punchouts, rutting, alligator cracking, IRI. The transverse cracking model in jointed plain concrete pavement (JPCP) is sensitive to coefficient of thermal expansion (CTE), thermal conductivity and climate. Faulting values are sensitive to dowels, thermal conductivity, co-efficient of thermal expansion, surface shortwave absorptivity (SSA) and climate zone. Punchouts are most sensitive to CTE. In flexible pavements airvoid content, traffic volume, and thickness of the asphalt layer, SSA and climate zone are the most sensitive parameters which affect rutting and alligator cracking. However, there are cases for which model predictions disagree with prevailing knowledge in pavement engineering. This study also revealed some problems associated with the software.