High-Temperature Performance of Asphalt Binder and Nano Silica-Aerogel Composite

The use of silica-aerogels has always been considered in industry due to its thermal insulation properties and low density. Research results show that use of aerogels in various industries, including the oil and paint industry, has reduced heat transfer and significantly increased insulation resistance. The aim of this study is to evaluate the effects of the silica-aerogel additive on mechanical and thermal properties of asphalt binder, especially at high temperature. To investigate these effects, initial tests were performed using classic asphalt tests, including penetration, softening point, ductility, and viscosity tests. Other experiments were performed to investigate the dispersion of aerogel nanoparticles in asphalt binder and its rheological properties, which are the field-emission scanning electron microscopy test for dispersion of nanoparticles, rotational viscosity test for the viscosity of asphalt binder, multiple stress creep recovery test for elasticity evaluation, differential scanning calorimetry test for thermal properties, and dynamic shear rheometer test for obtaining the high and intermediate pavement service temperature of asphalt binder. The results of using silica-aerogels in the amounts of 3%, 6%, 8%, and 10% by weight of asphalt binder showed that increasing the amount of aerogel to 3% can improve the performance of asphalt binder at high temperatures and increase the high service temperature, while asphalt will be able to effectively resist fatigue cracking. The results showed that adding silica-aerogel increases the resistance of rolling thin film oven (RTFO)-aged and unaged asphalt binders against rutting. Also, by increasing the amount of aerogel, the fatigue cracking factor (G*×sinδ) rises by 30% in the allowed range of 5,000 kPa. In addition, by increasing the amount of aerogel up to 3%, the thermal conductivity of asphalt binder has decreased up to 15 times. In general, it can be stated that the most important features of asphalt binder and silica-aerogel composite are high strength, low rutting potential, and long fatigue life.