Methods and compositions to increase performance of asphalt cement concrete comprising recycled asphalt pavement
The Present disclosure is related to hot-mix asphalt (“HMA”) which open new price/performance areas to asphalt cement concrete (“ACC”) pavement. Equivalent-performing pavement may be made at lower cost, or higher-performing pavement may be made at equivalent-to-prior-art cost. The amendments, recycled asphalt pavement (“RAP”, and including recycled asphalt shingles [“RAS”]), and reinforcing fiber (aramid fiber) may be adjusted as described herein to achieve a desired price/performance target.
1. A hot-mix asphalt (“HMA”) paving material comprising:
an aggregate including:
at least 10% by weight of recycled asphalt pavement (“RAP”), the RAP including oxidized bitumen;
asphalt binder (virgin bitumen);
reinforcing fibers; and
a liquid binder modifier that lowers the asphalt binder low temperature grade of the aggregate by at least one grade, wherein
the aggregate is to be placed and compacted by a paving machine to form a smooth surface.
2. The HMA paving material of claim 1 , wherein the liquid binder modifier lowers the asphalt binder low temperature grade by at least six grades.
3. The HMA paving material of claim 2 , wherein the liquid binder modifier lowers the asphalt binder low temperature grade by at least twelve grades.
4. The HMA paving material of claim 1 , wherein the aggregate includes from about 1 weight percent (wt. %) to about 6 wt. % of the liquid binder modifier with respect to the weight of the aggregate.
5. The HMA paving material of claim 1 , the aggregate is a homogeneous aggregate.
6. The HMA paving material of claim 1 , wherein an amount of the reinforcing fibers is from about 1 oz per mix ton to about 6 oz per mix ton.
7. The HMA paving material of claim 1 , wherein the reinforcing fibers are aramid fibers.
8. The HMA paving material of claim 7 , wherein the aramid reinforcing fibers are between 10 mm and 100 mm in length.
9. The HMA paving material of claim 1 , wherein the liquid binder modifier lowers the Performance Grade (PG) of the asphalt binder from −22 to −28.
10. The HMA paving material of claim 1 , wherein the liquid binder modifier lowers the Performance Grade (PG) of the asphalt binder from −22 to −34.
11. The HMA paving material of claim 1 , wherein the liquid binder modifier includes bio-oil, tree oils, corn-based oils, or soybean oils, or a combination thereof.
12. A suite of materials for increasing performance of asphalt cement concrete (“ACC”) pavement made with at least 10% recycled asphalt pavement (“RAP”) containing oxidized bitumen and asphalt binder (virgin bitumen), comprising:
a first quantity of aramid fibers having lengths between 20 mm and 80 mm; and
a second quantity of a liquid binder modifier that lowers the asphalt binder low temperature grade of the ACC by at least one grade.
13. The suite of materials of claim 12 , wherein the liquid binder modifier lowers the asphalt binder low temperature grade by at least six grades.
14. The suite of materials of claim 13 , wherein the liquid binder modifier lowers the asphalt binder low temperature grade by at least twelve grades.
15. The suite of materials of claim 12 , wherein the suite of materials includes from about 1 weight percent (wt. %) to about 6 wt. % of the liquid binder modifier with respect to the weight of the suite of materials.
16. The suite of materials of claim 12 , wherein an amount of the aramid fibers is from about 1 oz per mix ton to about 6 oz per mix ton.
17. The suite of materials of claim 12 , wherein the ratio between the first quantity and the second quantity is from about 12 to about 72.
18. The suite of materials of claim 12 , wherein the liquid binder modifier lowers the Performance Grade (PG) of the asphalt binder from −22 to −28.
19. The suite of materials of claim 12 , wherein the liquid binder modifier lowers the Performance Grade (PG) of the asphalt binder from −22 to −34.
20. The suite of materials of claim 12 , wherein the liquid binder modifier includes bio-oil, tree oils, corn-based oils, or soybean oils, or a combination thereof.