The effects of damage evaluation techniques on the prediction of environmental damage in asphalt mixtures

The main objective of this study was to investigate the effects of evaluation methods on the prediction of environmental damage (stripping) of hot mix asphalt (HMA). To achieve this objective, four different environmental damage evaluation techniques were used to evaluate asphalt mixtures prepared using different mix parameters. The environmental damage evaluation techniques include either percent reduction in indirect tensile strength or Marshall stability or percent increase in static creep deformation due to environmental damage. In addition, theTexas boiling test which is based on visual evaluation of the percent of coated aggregate was used for environmental damage evaluation. The findings of this study indicated that the estimated environmental damage is significantly affected by the method of evaluation. Retained indirect tensile strength and retained stability were found to be less sensitive to environmental damage. Moreover, the static creep test was the only method used that was able to monitor the effect of used asphalt and aggregate gradation on the environmental damage of HMA, while the effect of antistripping additives on reduction stripping was easily monitored by the Texas boiling and static creep test. Finally, it was found that different environmental damage evaluation techniques revealed different results of using calcium stearate hydroxide.