Study on Performance and Mechanism of SBR and Bio-Oil Recycled SBS Modified Asphalt

Abstract

With the continuous development of road construction and maintenance, SBS(Styrene-butadiene-styrene)-modified asphalt is widely used. However, there is no mature method for restoring aged SBS-modified asphalt. This study proposes the use of SBR(polymerized styrene butadiene rubber) and bio-oil for the restoration of aged SBS. In this study, five kinds of recycled asphalt were prepared by adding 5% bio-oil, 10% bio-oil, 6% SBR, 6% SBR + 5% bio-oil, and 6% SBR + 10% bio-oil to long-term aged SBS-modified asphalt. Softening point, penetration, and rotational viscosity experiments were tested to evaluate the conventional properties. Rheological tests revealed the performance of asphalt. Fourier transform infrared spectroscopy (FTIR), and atomic force microscope (AFM) tests were tested to demonstrate the microscopic characteristics of asphalt. Conventional tests investigated that aged asphalt viscosity will increase. Bio-oil could well recycle the asphalt viscosity. SBR could also soften aged asphalt, but its modification effect is limited compared with bio-oil. Rheological tests presented that the SBR and bio-oil have little impact on the temperature sensitivity of SBS-modified asphalt. SBR and bio-oil could decrease the asphalt stiffness. However, SBR and bio-oil could ameliorate the anti-cracking behavior of aged asphalt. The microscopic tests exhibited that SBR and bio-oil could decrease the asphaltene and colloid. Meanwhile, bio-oil could supplement alcohols and ethers at wave number 1000 cm−1–1270 cm−1. Alcohols and ethers are hard to oxidize, something which has a beneficial role in the anti-aged of recycled asphalt.

The Effects of Aging on Microstructures and Rheological Properties of Modified Asphalt with GO/SBS Composite

“…After the cyclohexane solution evaporated partially, the remaining black viscous liquid was poured into a flat mould and then placed in a drying oven at 50 °C for 24 h. Finally, the GO/SBS composites were taken out of the flat mould. Following this procedure, three kinds of GO/SBS composites containing different GO contents, accounting for 0.5, 1.0, and 1.5% of the total mass of the composite modifiers, were prepared successfully [ 29 ].…”

“…An AFM (atomic force microscope) test was employed to study the changes in the micromorphology of the asphalt surface before and after aging [ 29 ]. For the preparation of AFM samples, a drop of asphalt binder was dripped onto a glass slide.…”

Qualitative Evaluation for Asphalt Binder Modified with SBS Polymer

“…This increase is because when a suitable elastomer (like SBS) is put into bitumen, the bitumen's oily component is absorbed by the polymer, which causes it to expand (typically up to eight times its initial volume). This physical process might be affected by factors such as time, production technique, or additives[32,42,43]. As shown in Fig.13, when SBS was added to the plain asphalt binder, the binder's viscosity increased dramatically.…”