| The effect of transient temperatures in asphalt concrete (AC) is a critical factor in many applications. This includes modeling of transient thermal stresses, thaw-settlement associated with freezing and thawing cycles, temperature correction for Falling Weight Deflectometer data and weather related road maintenance. All these applications require knowledge of the transient temperature distribution in pavement structure.; Most of the research work on pavement temperature studies has dealt with the equilibrium state. These are based on an empirical correlation between pavement surface and air temperature. Limited work has addressed critical factors governing thermal transient behavior normally encountered in field conditions. Additionally, rapid implementation of existing transient temperature prediction models has been impaired by data limitations, specifically those related to asphalt concrete thermophysical properties.; Two pieces of laboratory equipment for investigating thermal properties and transient temperature distribution for compacted asphalt concrete were designed, developed and tested in this study. The two devices were used to carry out thermal properties testing and laboratory simulation of temperature distribution in asphalt concrete specimens. Thermal conductivities of laboratory compacted Superpave AC concrete specimens were observed to vary from 1.4 to 1.8 W/m.K for dense graded mixtures (Corresponding values of density and air voids were 2295--2450 kg/m3 and 3%--7%, respectively). Thermal diffusivity was observed to be in the range of 4.4--6.4% x 10-7 m2/s.; Laboratory investigation of the transient temperature distribution in asphalt concrete was undertaken using the UNB solar-convection simulator. The results of the two tests were applied in an explicit numerical transient state temperature prediction model formulated on the basis of the energy balance principle. The results show that the predicted pavement temperatures, based on the measured thermophysical properties, are consistent with the measured values. |
