Patent ID: 7374659

Claim:
A method for making a modified asphalt, comprising: blowing an oxygen-containing gas through a base asphalt at a high gas flow rate while simultaneously agitating the base asphalt at a high shear rate and at an elevated temperature in the range of about 120° C. to about 300° C. for a treatment time to thereby produce a modified asphalt; wherein the high gas flow rate, the high shear rate, the elevated temperature and the treatment time are all selected to substantially improve both the rutting resistance and the fatigue resistance of the modified asphalt as compared to the base asphalt; and wherein the base asphalt is agitated at a high shear rate supplying an amount of power to the base asphalt that corresponds to shearing a 3.5 kilogram sample at least about 5000 rpm for about one hour.