Assessment of Ground Tyre Rubber Impact on Stiffness Modulus and Cracking Resistance of Bituminous Mixtures

The objective of this study was to evaluate and characterize the performance of ground tire rubber (GTR) modified dense graded asphalt mixtures to recommend a suitable GTR content to produce a mix that provides superior pavement performance characteristics. The research effort encompassed investigation of stiffness and cracking resistance of six dense graded asphalt mixtures, including one conventional and five modified mixes covering 42 samples. Addition of GTR using wet process showed decrease in stiffness during loading. Cracking resistance of GTR modified mixtures increased with higher levels of dosages regardless of the base binder. An increase in the GTR dosage from 0 to 10% did not result in a significant change in fracture energy but a further increment to 25% increased the fracture energy. The laboratory Results indicated that 10% GTR was showed as the optimal content for the stiffness modulus and 25 % GTR as better content that provides better cracking resistance.