Bituminous composition
View Patent ↗This disclosure relates to bituminous compositions and methods of producing the same. More particularly, the disclosure relates to the production of bituminous compositions formulated with performance-graded bitumen-containing solvent-free bitumen emulsions which exhibit controllable, temperature-dependent interfacial rheology. When employed in paving applications, these bituminous compositions develop adhesive strength and load-bearing strength properties at rates comparable to traditional hot mix paving compositions and at rates faster than traditional cold mix paving compositions.
1. Bituminous composition comprising:
(a) a bitumen emulsion in an amount from 2% to 10% by total weight of the bituminous composition, wherein the bitumen emulsion comprises:
(i) hard bitumen in an amount from 50% to 75% by total weight of the bitumen emulsion, the hard bitumen being characterized by a penetration number of 100 dmm or less at 25° C. as determined according to the American Association of State Highway and Transportation Officials (AASHTO) Method T49, and
(ii) emulsifier in an amount from 0.05% to 2% by total weight of the bitumen emulsion, the emulsifier having a Hildebrand solubility parameter of at least 19 (MPa)½; and
(b) aggregate in an amount from 90% to 98% by total weight of the bituminous composition,
wherein the bituminous composition is at a temperature range of 50° C. to 140° C., the hard bitumen wets a surface of the aggregate, and the emulsifier enhances the bitumen wetting of the aggregate surface.
2. The composition of claim 1 , wherein the bitumen comprises at least one member selected from the group consisting of naturally occurring bitumen, bitumen from crude oil, bitumen from petroleum pitch, bitumen from coal tar, polymer-modified bitumen, rubberized bitumen, rubberized bitumen containing recycled tire material, acid-modified bitumen, wax-modified bitumen, and combinations thereof.
3. The composition of claim 1 , wherein the emulsifier comprises a functionality having a Hildebrand solubility parameter in a range of 19 (MPa)½ to 25 (MPa)½.
4. The composition of claim 1 , wherein the emulsifier comprises an emulsifier selected from a group consisting of anionic emulsifier, amphoteric emulsifier, cationic emulsifier, nonionic emulsifier, and combinations thereof.
5. The composition of claim 1 , wherein the bitumen emulsion comprises an organic solvent in an amount of less than or equal to 4% by weight by total weight of the emulsion.
6. The composition of claim 1 , wherein the aggregate comprises at least one member selected from the group consisting of dense-graded aggregate, gap-graded aggregate, open-graded, stone-matrix aggregate, reclaimed asphalt pavement material, reclaimed roofing shingles, and combinations thereof.
7. The composition of claim 1 , characterized by its application to a surface being paved at a temperature in a range of 0° C. to 120° C.
8. A paved road comprising at least one layer of the bituminous composition of claim 1 .
9. A method for producing a bituminous composition comprising steps of:
(A) preparing a bituminous emulsion comprising:
(a) hard bitumen in an amount from 50% to 75% by total weight of the bitumen emulsion, the hard bitumen being characterized by a penetration number of 100 dmm or less at 25° C. as determined according to the American Association of State Highway and Transportation Officials (AASHTO) Method T49,
(b) emulsifier in an amount from 0.05% to 2% by total weight of the bitumen emulsion, the emulsifier having a Hildebrand solubility parameter of at least 19 (MPa)½; and
(B) producing the bituminous composition having a temperature from 50° C. to 140° C. by mixing:
(i) the bitumen emulsion of step (A), having a temperature from 25° C. to 95° C., in an amount from 2% to 10% by total weight of the bituminous composition, and
(ii) aggregate having a temperature from 60° C. to 140° C., in an amount from 90% to 98% by total weight of the bituminous composition, to wet a surface of the aggregate with the hard bitumen and to enhance the bitumen wetting of the aggregate surface by the emulsifier.
10. The method of claim 9 , wherein the bitumen comprises at least one member selected from the group consisting of naturally occurring bitumen, bitumen from crude oil, bitumen from petroleum pitch, bitumen from coal tar, polymer-modified bitumen, rubberized bitumen, rubberized bitumen containing recycled tire material, acid-modified bitumen, wax-modified bitumen, and combinations thereof.
11. The method of claim 9 , wherein the emulsifier comprises a functionality having a Hildebrand solubility parameter in a range of 19 (MPa)½ to 25 (MPa)½.
12. The method of claim 9 , wherein the emulsifier comprises an emulsifier selected from a group consisting of anionic emulsifier, amphoteric emulsifier, cationic emulsifier, nonionic emulsifier, and combinations thereof.
13. The method of claim 9 , wherein the bitumen emulsion comprises an organic solvent in an amount of less than or equal to 4% by weight by total weight of the emulsion.
14. The method of claim 9 , wherein the aggregate comprises at least one member selected from the group consisting of dense-graded aggregate, gap-graded aggregate, open-graded, stone-matrix aggregate, reclaimed asphalt pavement material, reclaimed roofing shingles, and combinations thereof.