Warm mix asphalt binder compositions containing lubricating additives
The present invention provides a functionally dry warm mix asphalt binder composition modified with lubricating agents or additives that can be mixed with aggregate and compacted at temperatures substantially below asphalt binder compositions that do not contain the disclosed lubricating additives.
1. A paving process comprising:
(a) adding a lubricating additive comprising lubricating surfactant, lubricating non-surfactant, lubricating acid or combination thereof to functionally dry, essentially water-free, non-foamed asphalt binder containing less than 5 wt. % water and heated to a warm mix temperature to create a functionally dry warm mix lubricated asphalt binder composition, and if the lubricating additive in the warm mix lubricated asphalt binder composition comprises a lubricating wax, then the lubricating wax is 0.5 wt. % or less of the asphalt binder weight;
(b) combining the warm mix lubricated asphalt binder composition with aggregate and recycled asphalt pavement at a warm mix temperature that is lower than a comparison temperature needed to produce a comparison paving material without the lubricating additive;
(c) mixing to coat the aggregate and recycled asphalt pavement with the lubricated asphalt binder composition to form a warm mix paving material at the warm mix temperature;
(d) transferring the warm mix paving material to a paving machine;
(e) applying the warm mix paving material with the paving machine to a prepared surface at a warm mix paving temperature; and then
(f) compacting the applied paving material to form a paved surface.
2. A paving process according to claim 1 wherein the warm mix paving material is at a warm mix temperature of 280° F. or lower in step (c).
3. A paving process according to claim 1 wherein the warm mix paving material is at a warm mix temperature of 260° F. or lower in step (c).
4. A paving process according to claim 1 wherein the warm mix paving material is at 220-280° F. in step (c) and at 205-260° F. in step (e).
5. A paving process according to claim 1 wherein the warm mix paving material is paved at a warm mix temperature at least 30° F. lower than a comparison paving temperature needed for proper paving of the comparison paving composition.
6. A paving process according to claim 1 wherein the asphalt binder contains less than 1 wt. % water.
7. A paving process according to claim 1 wherein the asphalt binder contains less than 0.5 wt. % water.
8. A paving process according to claim 1 wherein the lubricating additive comprises an anionic surfactant, or ampholytic surfactant.
9. A paving process according to claim 1 wherein the lubricating additive comprises a cationic surfactant.
10. A paving process according to claim 1 wherein the lubricating additive comprises an alkyl amine, amido amine, alkyl quaternary ammonium salt, or heterocyclic quaternary ammonium salt.
11. A paving process according to claim 1 comprising adding a combination of lubricating additives to the asphalt binder.