Evaluation of Rutting Behavior of Density Deficient Asphalt Mixtures

Abstract

The purpose of this research has been to evaluate the effect of change in density on the rutting performance of the asphalt pavement. This investigation helps in determining the appropriate penalty for density deficient pavements based on the rutting performance. Permanent deformation tests were performed at 30, 40, and 50C on specimens with four different air void contents: 8, 8.75, 9.5, and 11%. More permanent deformation was observed at higher air voids and temperature. Complex modulus tests were also performed at the same four air void contents. Results showed that dynamic modulus decreases with the increase of both temperature and air void content as the asphalt mixture becomes softer at higher temperatures and air voids. Finally, a case study was performed to see the effect of air voids on the rutting behavior of the asphalt pavement. In this case study, the yearly rut depth for a certain pavement structure was predicted for both 8% and 11% air voids. Rut depth was determined to be 0.0074 inches for the 8% air voids pavement and 0.0168 inches for the 11% air voids pavement. This means that the pavement with 3% deficiency in air voids had an amount of rutting which is 2.3 times that of the in-specification pavement.