Efficacy of Softener for Enhancing Fatigue and Low-temperature Performance of Asphalt Binders with High RAP

Download or read book Efficacy of Softener for Enhancing Fatigue and Low-temperature Performance of Asphalt Binders with High RAP written by Sumon Roy and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of a higher percentage of reclaimed asphalt pavement (RAP) in asphalt concrete can lead to developing premature failure of asphalt pavements due to fatigue and/or low-temperature cracking. The incorporation of softening agents in asphalt binders can resolve these problems and enhance pavement durability. This study aims to evaluate the effectiveness of waste-based softening agents for enhancing the properties of asphalt mixes with high RAP contents. Waste cooking oil (WCO), and engine bottom oil (EBO) along with a commercial rejuvenator were investigated in this study. Three types of Performance Grade (PG) binders, each collected from two different sources, used in this study are PG 64-22, PG 70-22, and PG 76-22. These binders blended with different percentages of RAP binder (15, 25, 40, and 60%) were rejuvenated with different dosages (10, 15, and 20%) of the softening agents. Empirical tests (penetration), Acid-number (pH), Superpave tests, Multiple Stress Creep Recovery (MSCR), Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Saturates, Aromatics, Resins, and Asphaltenes (SARA) analysis, and limited mixture performance tests (Texas Boiling) were conducted. The rejuvenated binders showed a significant reduction in the binders' viscosities, resulting in a reduction of production temperatures as well as the brittleness of the hard binders. The fatigue factors of the rejuvenated binders decreased noticeably, indicating the improvement of fatigue cracking resistance. The Bending Beam Rheometer (BBR) results revealed that the rejuvenated binders exhibited a significant reduction in stiffness while increasing the rate of stress relaxation. The chemical analysis results revealed the appearance of some distinct peaks and changes in the % fractions of chemical constituents. The AFM test results agreed with the Superpave test data and showed that morphologies of the rejuvenated binders were changed and nanomechanical properties were altered noticeably. The TBT results showed that the WCO-modified RAP blend showed better performance than EBO. About 10% of WCO was found to be optimum for surface mixes with 25% RAP while EBO was less effective. The findings of this study are expected to help pavement professionals in selecting appropriate rejuvenators in the construction of pavements with high RAP.