Long term performance of warm mix asphalt versus hot mix asphalt

Ziari Hasan, Behbahani Hamid, Izadi Amir, Nasr Danial

(School of Civil Engineering, Iran University of Science and Technology, Tehran, 1684613114, Iran)

Abstract:the fatigue behavior, indirect tensile strength (ITS) and resilient modulus test results for warm mix asphalt (WMA) as well as hot mix asphalt (HMA) at different ageing levels were evaluated. Laboratory-prepared samples were aged artificially in the oven to simulate short-term and long term ageing in accordance with AASHTO R30 and then compared with unaged specimens. Beam fatigue testing was performed using beam specimens at 25 °C based on AASHTO T321 standard. Fatigue life, bending stiffness and dissipated energy for both unaged and aged mixtures were calculated using four-point beam fatigue test results. Three-point bending tests were performed using semi-circular bend (SCB) specimens at -10 °C and the critical mode I stress intensity factor K_I was then calculated using the peak load obtained from the load-displacement curve. It is observed that Sasobit and Rheofalt warm mix asphalt additives have a significant effect on indirect tensile strength, resilient modulus, fatigue behavior and stress intensity factor of aged and unaged mixtures.

Key words:warm mix asphalt; hot mix asphalt; fatigue behavior; resilient modulus; tensile strength; stress intensity factor; ageing