A mechanistic evaluation of modified asphalt paving mixtures.

摘要

This study has the objective of (1) exploring the effect of three commercially available asphalt modifiers in improving the mechanical properties of asphalt paving mixtures; (2) evaluating the effect of these modifiers on mitigating pavement distress and improving the overall pavement performance of pavement sections that are identical in all other layers, except in the top asphalt layer; and (3) assessing the economic feasibility of using these modifiers.; Twelve different binders were formulated with three asphalt grades and the addition of three different types of modifiers. The modifiers investigated were carbon black, neoprene latex, and polymerized asphalt (STYRELF). The dense graded asphalt paving mixture specimens were subjected to dynamic and creep tests at temperatures of 0, 40, 70, 100, and 140{dollar}spcirc{dollar}F, and the mechanical properties that were determine included resilient modulus, creep, permanent deformation parameters and fatigue life. Based on these properties, the VESYS IIIA pavement performance prediction model was utilized to assess the improvement, if any, of the modifier on the pavement distress and the overall performance.; The results of the study indicate that the effect of the modifier on the paving mixture properties was not significant at low temperatures, whereas its effect at high temperatures was pronounced. The predicted performance shows that carbon black was the most significant in reducing pavement rutting, while the polymer was the most significant in reducing fatigue cracking. All modifiers show some degree of improvement in the overall pavement performance. The economic assessment concluded that the use of carbon black and the polymer was economical compared with the use of conventional paving mixtures, whereas the economic feasibility of latex was questionable.