System and Method for High Throughput Preparation of Rubber-Modified Asphalt Cement

Abstract

This invention encompasses rubber modified asphalt cement compositions, as well as systems, apparatuses, methods for preparing, as well as methods for using rubber-modified asphalt cement compositions.

What is claimed is: 
     
         1 . A method for preparing a rubber-modified asphalt cement composition, comprising:
 i) contacting asphalt with rubber granules to form a mixture;   ii) heating the mixture to a temperature in the range of 450° F. to 510° F. to form a heated mixture;   iii) mixing at least a portion of the heated mixture with rubber granules in a pre-wet vessel comprising a mixer to form a heated wetted asphalt/rubber mixture; and   iv) passing the heated wetted asphalt/rubber mixture through at least one high shear mixer, wherein the rubber-modified asphalt cement composition has an integration value of at least 90.   
     
     
         2 . The method of  claim 1 , wherein the temperature is in the range of 460° F. to 510° F. 
     
     
         3 . The method of  claim 1 , wherein the temperature is in the range of 480° F. to 510° F. 
     
     
         4 . The method of  claim 1 , wherein the temperature is in the range of 490° F. to 510° F. 
     
     
         5 . The method of  claim 1 , wherein the rubber-modified asphalt cement composition has a rubber content in the range of 5-35 wt. % relative to the total weight of the rubber-modified asphalt cement composition. 
     
     
         6 . The method of  claim 1 , wherein the rubber-modified asphalt cement composition has a rubber content in the range of 5-15 wt. % relative to the total weight of the rubber-modified asphalt cement composition. 
     
     
         7 . The method of  claim 1 , wherein the rubber-modified asphalt cement composition has a rubber content of greater than 18 wt. % relative to the total weight of the rubber-modified asphalt cement composition. 
     
     
         8 . The method of  claim 1 , wherein the rubber-modified asphalt cement composition is an rubber-modified asphalt cement concentrate. 
     
     
         9 . An rubber-modified asphalt cement composition, prepared by:
 i) contacting asphalt with rubber granules to form a mixture;   ii) heating the mixture to a temperature in the range of 450° F. to 510° F. to form a heated mixture;   iii) mixing at least a portion of the heated mixture with rubber granules in a pre-wet vessel comprising a mixer to form a heated wetted asphalt/rubber mixture; and   iv) passing the heated wetted asphalt/rubber mixture through at least one high shear mixer, wherein the rubber-modified asphalt cement composition has an integration value of at least 95.   
     
     
         10 . The rubber-modified asphalt cement composition of  claim 9 , wherein the temperature is in the range of 460° F. to 510° F. 
     
     
         11 . The rubber-modified asphalt cement composition of claim herein the temperature is in the range of 480° F. to 510° F. 
     
     
         12 . The rubber-modified asphalt cement composition of  claim 9 , wherein the temperature is in the range of 490° F. to 510° F. 
     
     
         13 . The rubber-modified asphalt cement composition of  claim 9 , wherein the rubber-modified asphalt cement composition has a rubber content in the range of 5-35 wt. % relative to the total weight of the rubber-modified asphalt cement composition. 
     
     
         14 . The rubber-modified asphalt cement composition of  claim 9 , wherein the rubber-modified asphalt cement composition has a rubber content in the range of 5-15 wt. % relative to the total weight of the rubber-modified asphalt cement composition. 
     
     
         15 . The rubber-modified asphalt cement composition of  claim 9 , wherein the rubber-modified asphalt cement composition has a rubber content of greater than 18 wt. % relative to the total weight of the rubber-modified asphalt cement composition. 
     
     
         16 . A system for preparing an rubber-modified asphalt cement composition, comprising:
 i) an asphalt charging device for charging asphalt into the system;   ii) a rubber charging device for charging rubber granules into the system;   iii) at least one heater for heating the charged asphalt, the charged rubber granules, or a mixture thereof to a temperature in the range of 450° F. to 510° F.;   iv) at least one pre-wet vessel comprising a mixer to form a wetted asphalt/rubber mixture from the charged asphalt and charged rubber granules;   v) at least one high shear mixer for mixing the wetted asphalt/rubber mixture into the rubber-modified asphalt cement composition; and   vi) 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 value of at least 95.   
     
     
         17 . The system of  claim 16 , wherein the temperature is in the range of 460° F. to 510° F. 
     
     
         18 . The system of  claim 16 , wherein the temperature is in the range of 480° F. to 510° F. 
     
     
         19 . The system of  claim 16 , wherein the temperature is in the range of 490° F. to 510° F. 
     
     
         20 . The system of  claim 16 , wherein the rubber-modified asphalt cement composition comprises 5-15 wt. % rubber.