Impacts of lubricating oils on rheology and chemical compatibility of asphalt binders

Modifiers have been widely used to improve the engineering value of asphalt binders and the performance characteristics of asphalt mixtures. In recent years, a wide range of oil-based modifications have been introduced to improve asphalt binder performance, with the enhancement of the low-temperature characteristics as the specific goal. Using oil modification was found to improve the Superpave low-temperature performance grade (PG), but at the expense of the high-temperature PG grade. This paper studies different combinations of lubricating oils and also hybrid systems of polymers and lubricating oils in order to improve characteristics of seven different types of neat binder and also satisfy the needs for covering the required PGs. The laboratory performance of binders was evaluated in three main categories based on the temperature range of interest (i.e. high, intermediate and low service temperatures) using Superpave testing, damage characterising tests and chemical compatibility using gel permeation chromatography. Oil modification showed to be significantly effective in improving the rheological properties of modified binders across all performance temperature ranges specifically when they are applied in hybrid systems with polymers.