Experimental evaluation of the potential of the sap of the petroleum plant as an asphalt binder rejuvenating agent

The recycling of asphalt materials is increasing every year in the paving industry, mainly for economical reasons because it reduces the consumption of raw materials such as aggregates and asphalt binders. The use of higher contents of reclaimed asphalt pavement (RAP) is a challenge, since they are typically aged and show brittle behaviour, requiring the use of rejuvenators. The present work aims to investigate the potential of the sap of the Petroleum Plant (Euphorbia Tirucalli) as an asphalt rejuvenating agent. For this purpose, a PG 64-22 base asphalt binder was previously short and long term aged (by the rolling thin film oven test, RTFOT, and a pressure aging vessel, PAV, respectively), and then mixed with 30% by weight of the sap. All the samples (Original, RTFOT aged, PAV aged, and Rejuvenated) were subjected to physical tests (penetration and softening point), rheological tests (Rotational Viscosity and Frequency Sweep with a dynamic shear rheometer), multiple stress creep recovery and linear amplitude sweep tests. The results showed that, with the addition of the sap, penetration, softening point, master curves, rotational viscosity, MSCR parameters and fatigue curves of the PAV aged sample returned to the conditions it presented right after RTFOT procedure (or even to earlier stages), meaning that the sap was able to superimpose the effects of the oxidative aging. Thus, the sap of the Petroleum plant demonstrated potential as an asphalt rejuvenator.