Apparatus and process for manufacturing asphalt

• US 6,045,608 A
• Filed: 02/09/1999
• Issued: 04/04/2000
• Est. Priority Date: 02/09/1999
• Status: Expired

• Current Assignee: Ned B. Mitchell, Incorporated
• Original Assignee: Ned B. Mitchell, Incorporated
• Inventors: Mitchell, Ned B., Mitchell, Gil N.
• Primary Examiner(s): BRUNSMAN, DAVID M
• Application Number:
  US09/246,923
• Time in Patent Office: 420 Days
• Field of Search: 106/273.1, 106/276, 106/279, 106/280, 106/281.1, 106/284, 106/284.01, 106/284.02, 106/284.03, 106/284.04, 106/284.05, 106/284.06
• US Class Current: 106/273.1
• CPC Class Codes: C10C 3/007 winning and separation of asphalt from mixtures with aggregates, fillers and other products, e.g. winning from natural asphalt and regeneration of waste asphalt

Abstract

An improved process for making asphalt involves incorporating tar sands into a hot asphalt mix process and modifying the process. The improved process involves using a heated asphalt counter-flow drum mixer to admix asphaltic cement, coarse aggregate, and fine aggregate. During this mixing process, the admixture is heated to produce the asphaltic concrete. In the improved process from about 20 to about 80 percent tar sand is mixed with from about 80 to about 20 percent aggregate and from about 1 to less than about 5 percent liquid asphalt cement in a drum mixer to form an admixture, heating the admixture to a first elevated temperature (e.g., 250° and 400° F.) for a set period of time (e.g., 40 to about 90 seconds); and discharging the heated admixture at a second elevated temperature (e.g., from about 150° to about 350° F.) to produce asphaltic concrete. Preferably, the aggregate has a gradation of 10 to 25 percent passing a #4 sieve, and the admixture has substantially no added fines.

Claims

1. An improvement in a process for producing asphaltic concrete of the type involving using a heated asphalt counterflow drum mixer wherein a composition comprising asphaltic cement, coarse aggregate, and fine aggregate is heated and mixed in a hot mix process to produce the asphaltic concrete, the improvement comprising:

admixing a composition comprising from about 20 to about 80 percent tar sand, by weight, with from about 80 to about 20 percent aggregate, by weight, and from about 1 to less than about 5 percent, by weight, liquid asphalt cement in said drum mixer to form an admixture from said composition;

heating said admixture at a first elevated temperature for a set period of time; and

discharging said heated admixture at a second elevated temperature to produce asphaltic concrete.

2. The improvement of claim 1 wherein said liquid asphalt cement is present in said composition in an amount of about 1.5 to about four percent.

3. The improvement of claim 2 wherein the first elevated temperature varies between 250°

and 400°

F. and the set period of time is from about 40 to about 90 seconds.

4. The improvement of claim 3 wherein the second elevated temperature is from about 150°

to about 350°

F.

5. The improvement of claim 4 wherein the second elevated temperature is from about 200°

to about 2400 F.

6. The improvement of claim 4 wherein the composition comprises from about 65 to about 75 percent aggregate, from about 25 to about 35 percent tar sand and about 1 percent liquid asphaltic cement.

7. The improvement of claim 6 wherein the aggregate has a gradation of 10 to 25 percent passing a #4 sieve.

8. The improvement of claim 7 wherein the admixture has substantially no added fines.

9. Asphaltic concrete produced by the process of claim 1.

10. The asphaltic concrete of claim 9 wherein said asphaltic concrete is produced by a process containing liquid asphalt cement present in said composition in an amount of about one to about four percent.

11. The asphaltic concrete of claim 9 characterized in containing from about 65 to about 75 percent aggregate, from about 25 to about 35 percent tar sand and about 1 percent liquid asphaltic cement.

12. The asphaltic concrete of claim 11 wherein the aggregate used in the process has a gradation of 10 to 25 percent passing a #4 sieve.

13. The asphaltic concrete of claim 9 wherein the admixture used in the process has substantially no added fines.

14. An improvement in a process for producing asphaltic concrete of the type involving using a heated asphalt counterflow drum mixer wherein a composition containing asphaltic cement, coarse aggregate, and fine aggregate is heated and mixed to produce the asphaltic concrete, the improvement comprising:

admixing, without added fines, a composition, said composition comprising from about 65 to about 75 percent tar sand with from about 25 to about 35 percent aggregate, by weight, said aggregate having a gradation of 10 to 25 percent passing a #4 sieve, and from about 1 to about 4 percent liquid asphalt cement in said drum mixer to form an admixture from said composition;

heating said admixture at a temperature of about 250°

to about 350°

F. for from about 40 to about 90 seconds; and

discharging said heated admixture at a temperature of from about 200°

to about 240°

F. to produce asphaltic concrete.

15. The improvement of claim 14 wherein the admixture comprises about 1.5 percent liquid asphaltic cement.

16. Self-healing asphalt comprising a hot-mixed, hot laid admixture of comprising, by weight,

from about 20 to about 80 percent tar sand,

from about 80 to about 20 percent aggregate, and

from about 1 to less than about 5 percent, liquid asphalt cement.