Experimental investigation of the effect of using different aggregate types on WMA mixtures

AbstractIn recent years, production of warm mix asphalt (WMA) mixtures with the help of chemical additives has been developed due to obvious advantages, such as reduction of pollution emissions, construction temperature and the possibility of carrying asphalt in long distances. Various additives can have positive or negative effects on the performance characteristics of WMA mixtures made from different types of aggregates. Although, effects of different types of aggregates have been more investigated on the performance of hot mix asphalt (HMA), the effects on WMA have been less studied. Therefore, in this study, three types of aggregates including: limestone (Li), siliceous (Si) and slag (Sl) from the metal production factories together with Sasobit and Zeolite additives were provided to be used for the WMA mixtures. After constructing the asphalt samples and determining the optimum binder, Marshall Stability, indirect tensile strength tests and resilient modulus test and the durability parameter determination were performed. Test results indicated that WMA-Sasobit mixtures have the greatest impact on reducing consumed percentage of binder in slag and siliceous aggregates compared to limestone aggregates. For both additives, WMA mixtures containing limestone aggregates showed higher resilient modulus and siliceous aggregates showed lower resilient modulus. Moreover, the results of indirect tensile strength of specimens containing limestone aggregates showed the highest value and siliceous aggregates showed the lowest one. TSR in the limestone and slag aggregates was improved using both additives, but Zeolite additives reduce TSR in the siliceous aggregates