Experimental evaluation and modelling of low temperature failure properties of asphalt binders by means of the monotonic torsional loading test

Abstract

• The MTL test entails the use of a dynamic shear rheometer with 4 mm parallel plates. • Low temperature failure properties of asphalt binders were assessed with the MTL. • An improved modelling approach was used to derive discrete relaxation spectra. • Brittleness master curves and critical failure temperatures were determined. • The proposed approach highlights the enhanced toughness of polymer modified binders. A recent study showed the effectiveness of the monotonic torsional loading (MTL) test in evaluating low temperature failure properties of asphalt binders. The study described in this paper, which combines laboratory testing and data modelling, aimed at taking a step forward in the development of such a methodology. The MTL test, which involves using the dynamic shear rheometer (DSR) with 4 mm parallel plates, was employed to assess the performance of a set of selected asphalt binders of different types and origin in a wide range of testing conditions. Experimental results were processed with an improved modelling approach to derive the discrete relaxation spectra of investigated materials. Moreover, the time–temperature superposition principle was used to construct brittleness master curves, from which critical failure temperatures can be determined for any loading time. Outcomes of the investigation showed that the MTL test is extremely effective in evaluating and discriminating the low temperature failure properties of asphalt binders.