Investigation of Short-term Aging Resistance of Biochar Modified Asphalt

Chemical composition of asphalt which has a complex molecular structure changes due to temperature changes and atmospheric conditions. These changes cause aging of asphalt. Aging of asphalt occurs in three ways: oxidation, volatilization, and steric hardening. Oxidation of asphalt is not prevented but can be reduced. This study examined influences of short-term aging on properties of biochar modified asphalt. Biochar was produced with pyrolysis of tea plant waste supplied from the tea factory in Rize province. Chemical (scanning electron microscopy/energy dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy) and conventional asphalt tests were carried out on 50/70 asphalt penetration grade binder modified with biochar at the ratios of 0.5, 1, 2, and 4%. According to conventional asphalt tests, before short-term aging, as ratio of biochar added to 50/70 asphalt increases, the softening point and viscometer values of modified asphalt increase while the penetration value decreases. In addition, aging index (penetration aging ratio, softening point increment, viscosity aging index) was calculated using conventional asphalt test results of modified asphalt samples before and after aging. Biochar derived from pyrolysis of tea plant waste was increased aging resistance of asphalt by limiting its reaction with atmospheric oxygen. This study has proven that biochar obtained from waste organic biomass improves aging behavior of asphalt.