Experimental investigation of physical properties and accelerated sunlight-healing performance of flake graphite and exfoliated graphite nanoplatelet modified asphalt materials

- Measure the viscosity, light absorbance, thermal conductivity of graphite modified asphalt binder.
- Capture the infrared image of samples during healing process to study the temperature distribution.
- Analyze the displacements of sample particles during cyclic light healing processes by digital image correlation.
- Evaluate the healing capacity of graphite modified asphalt mixture beams by fracture-light healing tests.

This presented research investigated the physical properties and accelerated sunlight-healing performance of graphite modified asphalt materials. Two types of graphite materials, flake graphite and exfoliated graphite nanoplatelets (xGNP), were added to asphalt with different contents by weight. Asphalt binder tests were conducted to evaluate the performance of modified asphalt, including rotational viscosity, light absorbance, and thermal conductivity. The tests results of graphite modified asphalt showed increased viscosities, decreased activation energies, and increased light absorbance and thermal conductivity in comparison to the control asphalt. Afterwards, the graphite modified asphalt mixture beams (5% flake graphite and 2% xGNP) were prepared and used for cyclic fracture-light healing tests. The digital image correlation (DIC) was utilized to characterize the displacement changes in the fracture zone during the light healing process. The DIC results indicated that the improved healing performance of graphite modified asphalt mixtures and decreased healing displacement with light healing cycles. Finally, the measured recovered strength after each cycle was used to evaluate the healing performance of both the graphite modified and control samples. The results of cyclic fracture-light healing tests indicated that the graphite modified asphalt materials have significantly improved healing performance and therefore these materials have promises in promoting new light healing applications.