Apparatus and process for manufacturing 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.

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.  
 
     
     
       17. A composition resulting from hot mixing an admixture containing by weight:
   from about  20  to about  80  percent tar sand;        from about  80  to about  20  percent aggregate; and        from about  1  to about  5  percent liquid asphalt cement.     
     
     
       18. A self healing asphalt formed by hot laying the composition of  claim 17 . 
     
     
       19. A composition according to  claim 17 , wherein said tar sand component comprises recycled tar sand product. 
     
     
       20. A process for producing asphaltic concrete, comprising:
   forming an admixture containing by weight, about  20  to about  80  percent tar sand, about  80  to about  20  percent aggregate and about  1  to about  5  percent liquid asphalt cement;        heating said admixture in a vessel form a time interval; and        discharging said heated admixture from said vessel at an above ambient temperature.     
     
     
       21. Asphaltic concrete produced by the process of  claim 20 . 
     
     
       22. A process according to  claim 20 , wherein said tar sand component comprises recycled tar sand product. 
     
     
       23. A process according to  claim 20 , wherein said heated admixture is discharged from said vessel at a temperature between about  150  and about  350  degrees Fahrenheit.