Process for cold-in-place recycling using foamed asphalt and lubrication additive
Cold-in-place asphalt recycling is disclosed. A foamed asphalt may be produced by injecting water and optionally compressed air into a hot asphalt stream. A lubricating surfactant may be added to the hot asphalt stream to improve performance. The foamed asphalt may be mixed with reclaimed material to provide a uniformly coated paving material that can compacted to a desired density.
1. A cold-in-place asphalt recycling method using a foamed asphalt binder, the method comprising the steps of:
combining water and a lubricating surfactant, and optionally compressed air, with an asphalt binder heated to a reduced temperature of about 300° F. to about 380° F. to provide a foamed asphalt binder; and
combining milled bituminous material with the foamed asphalt binder to provide a coated cold-in-place recycled paving material; and
compacting the coated cold-in-place recycled paving material.
2. The method of claim 1 , wherein water comprises about 0.5 to about 5 weight percent and the lubricating surfactant comprises about 0.05 to about 3 weight percent of the heated asphalt binder.
3. The method of claim 1 , comprising combining the milled bituminous material with the foamed asphalt binder in an amount of about 0.5 to 4 percent asphalt binder by weight of milled bituminous material.
4. The method of claim 1 , comprising injecting water and compressed air into heated asphalt binder containing the lubricating surfactant.
5. The method of claim 1 , comprising injecting water, compressed air, and lubricating surfactant into heated asphalt binder.
6. The method of claim 1 , comprising adding lubricating surfactant to the heated asphalt binder and then injecting water into the heated asphalt binder.
7. The method of claim 1 , wherein the lubricating surfactant comprises a cationic, anionic or nonionic surfactant.
8. The method of claim 1 , wherein the lubricating surfactant comprises an alkyl amine, alkyl quaternary ammonium salt, heterocyclic quaternary ammonium salt, amido amine or non-nitrogenous sulfur or phosphorous derivative.
9. The method of claim 1 , wherein the lubricating surfactant comprises an ethoxylated diamine.
10. The method of claim 1 , wherein the foamed asphalt binder is formed from about 0.5 to about 5 weight percent water and, the lubricating surfactant comprises about 0.05 to about 3 weight percent ethoxylated diamine.
11. The method of claim 1 , wherein the lubricating surfactant reduces the temperature needed for paving by as much as 60° F.
12. The method of claim 1 , wherein the asphalt is heated at a temperature of about 320° F. to about 360° F.
13. A cold-in-place asphalt recycling method for paving a recycled asphalt pavement surface, which method comprises:
producing a foamed asphalt binder by injecting water and a lubricating surfactant and optionally compressed air into a stream of an asphalt binder at a reduced temperature of about 300° F. to about 380° F.;
milling an existing pavement surface to provide milled bituminous material;
combining the foamed asphalt binder with the milled bituminous material to produce a recycled bituminous mix;
conveying the recycled bituminous mix into a paver;
laying the recycled bituminous mix onto an existing grade; and
compacting the recycled bituminous mix to form a recycled asphalt pavement surface.
14. The method of claim 13 , further comprising combining virgin aggregate and the milled bituminous material with the foamed asphalt binder.
15. The method of claim 13 , wherein the lubricating surfactant reduces the temperature needed for paving by as much as 60° F.
16. The method of claim 13 , further comprising placing a hot mix asphalt layer on the recycled asphalt pavement surface.
17. The method of claim 13 , wherein the asphalt is heated to a temperature of about 320° F. to about 360° F.
18. The method of claim 13 , wherein the lubricating surfactant comprises a cationic, anionic or nonionic surfactant.
19. The method of claim 13 , wherein the lubricating surfactant comprises an alkyl amine, alkyl quaternary ammonium salt, heterocyclic quaternary ammonium salt, amido amine or non-nitrogenous sulfur or phosphorous derivative.
20. The method of claim 13 , wherein the lubricating surfactant comprises an ethoxylated diamine.