Life-Cycle Cost Analysis of Graphene Oxide Modification of a Neat Asphalt Binder for Flexible Pavement

Graphene oxide (GO) has the potential to increase the service life of asphalt binders and asphalt mixtures, but there are concerns about its high cost. The purpose of this work is to provide a methodology to perform a cost-benefit analysis of using GO in a neat asphalt binder for a simulated asphalt pavement construction project with estimated long-term engineering performance in Colorado. The rheological properties, creep behavior, and cracking resistance of a control performance grade (PG) 64-22 binder and GO-modified binders were evaluated in the laboratory. GO in a loose powder form was mixed with the PG 64-22 binder in dosages of 0.05% and 0.2% by weight. Rheological binder test results indicated the GO improved the rutting resistance of the binder, with the 0.05% GO binder providing greater rutting resistance than the 0.2% GO binder. The 0.05% and 0.2% GO binders exhibited minor improvement in fatigue cracking and thermal cracking resistance as compared to the control binder. The test results were input into the AASHTO Pavement ME software with regional traffic and climate conditions to estimate the predicted performance using the different GO dosages. When comparing the Pavement ME service life results based on rutting performance, it was determined the 0.05% and 0.2% GO binder asphalt pavement mixtures lasted approximately 9 and 5 years longer than the control binder, respectively. The Pavement ME service life results for international roughness index (IRI), bottom-up cracking, top-down cracking, and thermal cracking were not significantly different between the control and GO-modified binders. A preliminary deterministic life-cycle cost analysis based on rutting performance on a 16.1-km (10-mi) highway section in Colorado revealed that GO addition to a neat asphalt binder at the 0.05% target dosage in this study is not a cost-effective option at its current price; however, future manufacturing improvements and mass fabrication could bring GO production costs down to viable levels for practical implementation in asphalt pavement construction.