Laboratory Evaluation of Asphalt Mixtures Containing Sustainable Technologies

The laboratory properties of asphalt mixtures containing sustainable technologies were evaluated. Sustainable technologies included crumb rubber modifier (CRM), reclaimed asphalt pavement (RAP), engineered rejuvenator including de-metalized oil and resin, plant-based rejuvenator, and sulfur-based additive. Laboratory testing evaluated the rutting performance, moisture resistance, fatigue performance, and fracture resistance of the produced mixtures using the Hamburg loaded wheel tester, the flow number test, the dynamic modulus test, the modified Lottman test, the semi-circular bending (SCB) test, and the dissipated creep strain energy (DCSE) test. In general, asphalt mixtures prepared with polymer-modified PG 76-22 and low percentages of RAP were the overall best performers in the experimental program. Results of the experimental program also showed that the rutting performance of sulfur-modified warm mix asphalt (WMA) was comparable or superior to conventional mixes. However, results of the fracture tests and the fatigue parameter in the dynamic modulus test showed that the sulfur-modified WMA is more susceptible to cracking than conventional mixes given its stiffness characteristics. The mixture containing 15% RAP performed similarly to the conventional mixture prepared with the same binder grade and passed the performance requirements of the individual tests. The mixture prepared with high RAP content (40%) and the engineered additive outperformed the conventional mixture prepared with the same binder grade in all test results. Field validation of the performance of this mix is recommended for increased use in sustainable construction. However, further evaluation of the plant-based rejuvenator is needed. The mixture prepared with CRM performed satisfactorily against the major distresses with the exception of moisture sensitivity.