The effect of sustainable materials on fatigue cracking of thing overlay asphalt mixture

Abstract

The life of the pavement affected by several factors that play a main role in the performance of asphalt pavement, one of these factors the failure modes, can be represented the important factors that reduced the service life of flexible pavements. Fatigue cracking failure of all the types of failures modes, it is still considered the most common failure mode in recent years. Improvement the performance of pavement by good field works or by enhancing the properties of HMA mixtures represents the essential target by engineers to reduce the maintenance cost and to mitigate potential safety problems. Therefore, this study aims to assess the effect of polymer modified asphalt (PMA); waste material namely crumb rubber with low density polyethylene (LDPE) were used as a combined admixture or as single additive as a sustainable material to enhance the fatigue properties of thin overlay asphalt mixture. 15% of 250-micron crumb rubber was added, while 2.5, 5, 7.5, and 10 % LDPE were added to produce PMA. The flexural beam fatigue test was performed at temperature of (20 C) to describe the fatigue life of modified thin overlay asphalt mixtures. Results exhibit the vital role of crumb rubber in increase the fatigue life of the mix as compared to conventional mixtures, while LDPE showed a significant role in increase fatigue life of thin overlay asphalt mixture. Fatigue life increase when the 15% of Crum Rubber Modifiers added to the binder. Also fatigue life increase when low density polyethylene (LDPE) added for a high percentage; from the analysis of the result that asphalt mixtures contain (7.5% and 10%) low density polyethylene (LDPE) in addition of 15% of Crumb Rubber Modifier (CRM) achieved the best fatigue life because of the effect of modifiers properties such as flexibility, elasticity, as well as laboratory conditions. Thus, this emphasis the ability of waste material to enhance the asphalt mixture and upgrade such mixture in a sustainable approach.