Study on the Technological Conditions of Crumb Tire Rubber-Modified Bitumens

The use of waste tire rubbers as bitumen modifiers can contribute to alleviating pollution problems caused by discarding scrap tires. This article deals with the preparation and influencing factors of bitumens modified by crumb tire rubber. The performance of crumb tire rubber-modified bitumens (CTRMBs), such as penetration grade, softening point, and ductility, have been studied as a function of rubber selection, shearing temperature, shearing rotational speed, shearing time, rubber addition, and blended oil addition. From the experimental results obtained, optimal technology conditions were determined as: a shearing time of 40 min, a shearing temperature of 180 degrees C, a shearing rotational speed of 7000 rpm, a rubber addition less than 25 wt%, and a blended oil addition less than 4 wt% during manufacturing operations. By using blended oil, the modified asphalt that measured up to standard of the crumb rubber-modified asphalt (FHWA-SA-92-002) was prepared, following the process flow diagram.