Fatigue and self-healing characterization of asphalt composites containing rock asphalts

Fatigue cracking is one of the major distresses that causes early pavement failures. One of the solutions to delay the occurrence of pavement failure by fatigue cracking is to use materials that not only can resist such cracking but also can heal them over time. This is therefore necessary to evaluate the impact of such materials on fatigue cracking resistance and self-healing properties of asphalt mixtures. The increasing use of alternative materials such as rock asphalts has made this need even more pronounced. Fittingly, this paper presents the findings from a study that utilizes a fracture test and a combined fatigue-healing test to evaluate the influence of different sources of rock asphalts-Buton, Qingchuan (QC) and Uintaite Modifier (UM) on the fatigue and self-healing properties of fine aggregate matrix (FAM) mixture. The fracture test results indicate that rock asphalt can effectively improve the cracking resistance of asphalt mortars or FAM. The viscoelastic continuum damage (VECD) analyses of the combined fatigue-healing test results show that rock asphalt can significantly enhance the fatigue cracking resistance of FAM mixture. The results also show that, at same volume concentration of binder, UM rock asphalt and QC rock asphalt enhance fatigue cracking resistance of FAM very similarly but much better than does the Buton rock asphalt. An increase in the concentration of Buton rock asphalt made the FAM mixture even more resistant to fatigue cracking. Similarly, test results show that, at same volume concentration of binder, QC rock asphalt exhibited the best self-healing properties followed by UM and Buton rock asphalt, respectively. This ranking was more pronounced with longer rest period durations. Test results also indicate that, at same rest period, 8% Buton rock asphalt healed better than 20% Buton rock asphalt. In addition, this paper also uses these materials to demonstrate an experimental and analytical approach to quantity both fatigue cracking resistance and self-healing properties using a viscoelastic continuum damage model and a single unified testing protocol with asphalt mortars or FAM. This approach can also be easily applied to evaluate other similar materials such as reclaimed asphalt pavements (RAP).