System and method for high throughput preparation of rubber-modified asphalt cement

1. A method for preparing a rubber-modified asphalt cement composition, comprising:

contacting asphalt with tire rubber granules to form a mixture;

heating the mixture; and

passing the heated mixture through at least one high shear mixer;

wherein the rubber-modified asphalt cement composition comprises an integration value of at least 90 and the tire rubber within the rubber-modified asphalt cement has an average size of less than about 20 microns.

2. The method of claim 1 , wherein the heating step comprises heating the mixture to a temperature of at least about 500° F.

3. The method of claim 1 , wherein the passing step comprises passing the heated mixture through the at least one high shear mixer for greater than 30 minutes.

4. A method for preparing a rubber-modified asphalt cement composition, comprising:

contacting asphalt with tire rubber granules to form a mixture;

heating the mixture to a temperature of at least about 500° F.; and

passing the heated mixture through at least one high shear mixer for greater than 30 minutes;

wherein the tire rubber within the rubber-modified asphalt cement has an average size of less than about 20 microns.

5. The method of claim 4 , wherein the rubber-modified asphalt cement composition comprises an integration value of at least 95.

6. A method for high throughput preparation of a rubber-modified asphalt cement composition, comprising:

contacting asphalt with at least 40,000 pounds of tire rubber granules to form a mixture;

heating the mixture; and

passing the heated mixture through at least one high shear mixer;

wherein the rubber-modified asphalt cement composition comprises an integration value of at least 95 and the tire rubber within the rubber-modified asphalt cement has an average size of less than about 20 microns, and

wherein the method is performed in less than 24 hours.

7. The method of claim 6 , wherein the rubber-modified asphalt cement composition comprising about 65-95 wt. % of asphalt and about 5-35wt. % of tire rubber granules.

8. The method of claim 6 , wherein the heating step comprises heating the mixture to a temperature of at least about 500° F.

9. The method of claim 6 , wherein the passing step comprises passing the heated mixture through the at least one high shear mixer for greater than 30 minutes.

10. A rubber-modified asphalt cement composition prepared by:

contacting asphalt with tire rubber granules to form a mixture;

heating the mixture; and

passing the heated mixture through at least one high shear mixer;

wherein the rubber-modified asphalt cement composition comprises an integration value of at least 95 and the tire rubber within the rubber-modified asphalt cement has an average size of less than about 20 microns.

11. The composition of claim 10 , wherein the mixture is heated to a temperature greater than 500° F.

12. The composition of claim 10 , wherein the heated mixture is passed through the at least one high shear mixer for greater than 30 minutes.

13. The composition of claim 10 , wherein the rubber-modified asphalt cement composition comprises about 65-95 wt. % of asphalt and about 5-35 wt. % of tire rubber granules.

14. A system for preparing a rubber-modified asphalt cement composition, comprising:

an asphalt charging device for charging asphalt into the system;

a rubber charging device for charging tire rubber granules into the system;

at least one heater for heating the charged asphalt, the charged tire rubber granules, or a mixture thereof;

at least one high shear mixer for mixing the charged asphalt and charged tire rubber granules into a rubber-modified asphalt cement composition; and

a controller for controlling the asphalt charging device, the rubber charging device, and/or the at least one high shear mixer, in a manner such that the rubber-modified asphalt cement composition has an integration factor of at least 95 and the tire rubber within the rubber-modified asphalt cement has an average size of less than about 20 microns.

15. The system of claim 14 , wherein the system is capable of high throughput production in less than 24 hours of a rubber-modified asphalt cement composition comprising at least 40,000 pounds of tire rubber granules,

wherein the composition has an integration value of at least 95.

16. The system of claim 14 , wherein the controller is a semi-automatic controller.

17. The system of claim 14 , wherein the controller is an automatic controller.

18. The method of claim 1 , wherein the rubber-modified asphalt cement comprises less than 8 wt. % tire rubber that is in a solid state.