Laboratory Evaluation of Performance Properties of Rubberized Asphalt Mixtures Containing High RAP Percentages

In recent years، some by-products such as crumb rubber (CR) and reclaimed asphalt pavement (RAP) have been used to save money، protect the environment and extend the life of asphalt pavements. Resilient modulus is one of the most important index and property of material for predicting material reaction under repeated or moving load. Also، it is important variable in pavement design methods. In this laboratory research، influence of CR and RAP on indirect tensile strength (ITS) and resilient modulus of hot mix asphalt (HMA) mixtures was investigated. In this research، aggregate gradation #5 (Iran Code #234)، ambient crumb rubber (40 mesh)، three rubber content (0%، 10% and 20% bitumen weight)، four RAP content (0%، 20، 40% and 60% mix weight) and one penetration grade virgin binder (85/100) was used. The results indicated that، as the RAP content increases، ITS and resilient modulus values decreases and rutting resistance increase while، addition of CR in bitumen of mixtures leads to decrease in ITS and resilient modulus values and increase rutting resistance of mixtures.