Enhancing effect of microalgae biodiesel incorporation on the performance of crumb Rubber/SBS modified asphalt

In this study, microalgae biodiesel (MB) was prepared by chemically modifying microalgae acidified oil, which was in turn added as a modifier to a pre-synthesized crumb rubber-styrene-butadiene-styrene (CR/SBS) modified asphalt to prepare MBCR/SBS composite modified asphalt. Rotational viscosity measurement showed that viscosity of MBCR/SBS-2 asphalt meets the requirements of Superpave specifications. Dynamic shear rheometer and multiple stress creep recovery tests revealed that MBCR/SBS-2 asphalt exhibited the largest complex modulus (G*), smallest phase angle (delta) in high frequency range, and higher average recovery rate (R) after rotating thin film oven test. The fatigue cracking analysis revealed that higher content of MB results in better resistance to fatigue cracking under intermediate temperature. Separation analysis showed that MBCR/SBS-2 asphalt possessed softening point difference of 2.9 degrees C. Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy analyses confirmed more unsaturated groups in the MB than in the base asphalt, and amide groups bonded to the free radicals of CR which promoted the development of network structure resulting in enhanced mechanical properties of MBCR/SBS modified asphalt than pristine CR/SBS asphalt. In addition, a proposed synthesis and performance mechanism of MBCR/SBS asphalt was elaborated. This study based on simplified preparation and enhanced performance of MBCR/SBS asphalt composite modified asphalt, could be of potential interest for practical applications in construction and highway industries. (C) 2019 Elsevier Ltd. All rights reserved.