Improving the rutting resistance of asphalt pavement modified with the carbon nanotubes additive

Abstract

Up to the present time, assiduous efforts were devoted to mitigating the development of asphaltic pavement rutting. To this intention, nanotechnology recently received considerable attention to magnify the resistance against such distress. This work elucidated the worthiness of utilizing the industrial carbon nanotubes, CNT, as a strengthening additive. Accordingly, four dosages with an upper limit of 2.0% from this nanoscale material were added to two bitumen grades, 40/50 and 60/70. The modified binders were subjected to several tests including penetration, softening point, viscosity, and rheological properties. Furthermore, sets of cylindrical and slab-shaped specimens containing these binders were fabricated and underwent volumetric analysis, Marshall test in addition to rut measurement by the wheel tracking test. The outcome of this work revealed that higher viscosity bitumen consumes relatively less amount of the CNT with a better rutting performance rate and Marshall stability, whereas the 40/50 grade yielded an increase in rutting resistance by 61.0% and stability by 35.0% at 1.5% of the CNT while the 60/70 grade needed 2.0% of this material to be near these improving values. Regarding the Superpave rutting indicator addressed by G*/sin δ, a continuous ascending tendency was observed by adding the CNT for the basic and aged conditions. The cost analysis results specified the 1.5% of CNT mixed with 40/50 bitumen to be the threshold of economic feasibility, any further dosage or utilizing softer bitumen will omit its viability. All the results have been subjected to a comprehension statistical analysis that produced a significant regression model.

Keywords

• Asphalt pavement rutting
• Carbon nanotubes
• Wheel tracking test
• Cost analysis
• Statistical analysis