Laboratory evaluation of rutting resistance for asphalt binders and mixtures modified with different thermochromic microcapsule powders

Asphalt binder absorbs a lot of solar energies in summer and causes many pavement distresses and environmental problems. Thermochromic microcapsule powder (TMP) has been applied into asphalt binders as pavement materials since it reversibly changes its colors and dynamically adjusts the reflectivity to solar radiation according to temperature variations. In this research, the rutting resistance of TMP modified asphalt binders was evaluated by the physical properties tests, temperature and frequency sweep test, and multi-stress creep recovery test. The effects of base binder types, TMP types, and TMP content were investigated. The repeated load permanent deformation test was performed on TMP modified asphalt mixtures to verify the findings obtained from the binder performance tests. It is found that two types of TMP show the opposite effects. The use of one type of TMP reduces the rutting resistance of asphalt binders while the use of another improves it. The effect becomes more significant with the increase of TMP content. All TMP modified asphalt binders exhibit low stress-dependence. The consistent findings are obtained from both binder and mixture performance tests. Nonrecoverable creep compliance of asphalt binders is a rational indicator to predict the rutting resistance of different types of asphalt mixtures. The potential reasons for the different modification effects of two types of TMP are preliminarily discovered. (C) 2020 Elsevier Ltd. All rights reserved.