Investigation of self healing behaviour of asphalt mixes using beam on elastic foundation setup

Self healing of asphalt mixes is known for more than four decades. However, it is a complex phenomenon which depends on the duration of the rest period, temperature, crack size, etc. In order to quantify the self healing behaviour of asphalt mixes, a test setup was proposed in this research using an asphalt beam on an elastic foundation. Within this setup, a notched asphalt beam was glued on a low modulus rubber foundation, and a symmetric monotonic load was applied with loading-unloading-healing-reloading cycles. The rubber foundation was used to avoid permanent deformation and to ensure a controllable healing process. Experimental results indicate that the beam on elastic foundation (BOEF) setup is capable for self healing investigations of asphalt mixes. The healing process was quantified by the recovery of the strength and the recovery of the crack opening displacement. The time, temperature and crack size dependency of the self healing behaviour were observed over the healing periods. Moreover, a self healing model was proposed to decompose the self healing phenomenon observed in the BOEF healing tests. It is shown that at the beginning of the healing period the delayed visco-elastic healing is the main reason of the recovery of the crack opening displacement and the viscous healing is important for healing after longer time/higher temperature.