Laboratory studies about the interaction of asphalt cement with three different ground tire rubber (GTR) samples from different gradations were made using rheological and aging tests, and also chemical characterization tests. Rubber particle size, curing time, temperature and mixing rate were found to be important factors that affect the rubber depolymerization rate. It is possible to obtain homogeneous asphalt-rubber binders with nondetrimental viscosity at hot-mix temperatures, while still being elastic at rutting temperatures and less stiff at colder temperatures than base asphalt.The higher the rubber content in asphalt rubber, the better the cold stiffness properties and fatigue resistance, the lower the aging index. The proper combination of curing variables and asphalt composition is essential to assure good rheological properties. The high molecular size, the high asphaltenes content and high acidity in the asphalt cements resulted in blends more easily compatible and with good rheological properties.

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