Case Studies in Construction Materials (Jul 2023)
Laboratory evaluation of carbon nanotubes modified bio-asphalt
Abstract
With the construction of road engineering and asphalt pavement maintenance, the asphalt demand has been increasing. Petroleum asphalt reserves are limited. It is urgent to find a substitute for petroleum asphalt. In order to ensure the sustainable development of asphalt road construction, biologic materials were successfully applied to petroleum asphalt. Biologic materials can reduce the demand of petroleum asphalt. First, the different contents of bio-asphalt were set to be in the range (2.5–10 %). Carbon nanotubes (CNT) were used to enhance the bio-asphalt high-temperature behavior, hence a carbon nanotubes modified bio-asphalt (CTMBA) was prepared. Secondly, the conventional tests were conducted to reveal the performance of CTMBA. The optimum content of bio-oil and CNT were determined by utilizing rheological properties, including temperature scanning, frequency scanning, and BBR test. Finally, the fluorescence microscope was carried out to investigate the compatibility and dispersion among bio-oil, CNT, and neat asphalt. The results showed that CNT could significantly enhance the temperature sensitivity, viscosity, and high-temperature property of CTMBA. However, CNT could decrease the CTMBA ductility and low-temperature property. Bio-oil could increase the ductility and low-temperature property of CTMBA but reduces its deformation capacity. When the CNT and bio-oil contents in the range 1.5–2 % and 5–7.5 %, respectively, CTMBA could maintain outstanding rheological properties. It was found that there was no fluorescent material in the bio-asphalt. However, there were obvious fluorescent substances in the CNT-modified neat asphalt and CTMBA. Fluorescence microscope images showed that bio-oil, CNT, and neat asphalt had excellent compatibility.
