Resistance to moisture and frost of a cold fine-graded asphalt mixture with a composite binder

Maintenance works in an asphalt pavement for removing and replacing the wearing course produce large amounts of milled material. Following the sustainably-sourced resource principle, this material is recirculated and, in this case, utilized in new mixtures, chiefly in cold recycled mixes. Since it is derived from surface course rehabilitation, its particle size is up to 10 mm. To ensure the most beneficial parameters of so produced cold mix asphalt, the properties of the binder have to be optimized. The binder used in the tests was composed of CEM I 32.5R, hydrated lime and by-product fines. Various combinations of binder components were tested in this study to obtain the optimal parameters of the recycled mix. Foamed bitumen 70/100 was used. Void characteristics were evaluated, and a particular focus was on the resistance to moisture and frost-induced damage, i.e., ITSR, TSR, and RWWM according to ASSHTO T283. A series of tests enabled the determination of the composite binder composition to ensure proper resistance of a cold recycled fine-graded mixture to moisture and frost.