Effect of Hydrated Lime Additive on the Performance of Warm Mix Asphalt

Warm mix asphalts (WMA) have advantages and disadvantages in comparison with common asphalt mixtures. Most of the advantages of WMA are related to the low temperature of the production, environmental issues, less bitumen aging, reduction in fuel consumption and extension of the possible period for constructing the asphalt during the year. Warm mix asphalts have disadvantages such as weak performance in moisture damage. In this study, the effect of hydrated lime, which is an amendment material in similar cases, in modifying of this property and improving other properties, like rutting, dynamic module and creep resistance, will be analyzed. The cost problem is well-considered in selecting the amendment material, so as to preserve the greatest advantages of WMA, which are reduction in production cost and ease of accessibility. For this purpose, different amount of hydrated lime (0, 1, 2, 3 and 4 percent of aggregates) was added to WMA as filler, and then, the creep, moisture damage, dynamic module and rutting tests were performed. It was concluded from the obtained results that hydrated lime can be used in WMA as an anti-stripping and resistant to moisture damage material. Using hydrated lime for 2% of aggregates as a replacement for part of the filler in WMA is recommended.