Abstract
The use of asphalt-rubber has been mandated without the needed experience, design procedures, and construction guidelines. The purpose of this study is to determine optimal blend parameters that will enable maximum performance of the asphalt-rubber binder. The selected variables chosen are curing time, curing temperature, rubber content (weight percent), rubber particle size, base asphalt type, and carbonyl area. Results confirmed that the addition of rubber increased the viscosity of the asphalt binder at high temperatures, lowered the creep stiffness of the binder at low temperatures, and improved the overall temperature susceptibility. Increasing the rubber content in the asphalt was shown to further improve pavement performance. In addition, the use of smaller particles of rubber was found to decrease the creep stiffness at low temperatures (<-152C). However, it did not increase the viscosity at high temperatures ( >60QC). It was also determined that the type of asphalt and the type of rubber play important roles of meeting the criteria of an improved asphaltrubber binder. For example, the Murphy asphalt reblended with Sun recycling agent (AC-5) showed the least improvement to the addition of rubber compared with the Fina AC-10, Exxon AC-10, and Exxon AC-5. With respect to rubber type, the Rouse rubber was determined to improve Theological properties of the asphalt-rubber binder more than the Tire-Gator rubber. The curing process was also shown to increase the breakdown of the rubber into the asphalt. This phenomenon can be attributed to the devulcanization of the rubber in the mixer apparatus where extreme shear rates and temperatures were used.
Koo, Heamo Lee (1996). An investigation of the use of tire rubber in asphalt. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1996 -THESIS -K663.