Study on the use of low field nuclear magnetic resonance for detecting asphalt aging

Abstract

Authors of this paper recently introduced the application of Low Field Nuclear Magnetic Resonance (LF-NMR) to evaluate the aging state of asphalt mix samples. This method was able to determine the aging trends of asphalt samples based on the viscosity of their binders. In this study, binders were extracted from the asphalt mix samples that were previously analyzed using LF-NMR. The rheologi-cal properties of the binders were determined using a Dynamic Shear Rheometer (DSR). The extracted binders were also characterized using a LF-NMR probe that allows the measurement of short echotimes, which is more accurate compared to the standard probe. The LF-NMR displayed the same viscosity trends detected by the DSR. Both methods showed that the binder viscosity follows an increasing trend as the aging time increases, as expected. However, smaller differences appear for binders that were extracted from samples aged for the same period but containing different air voids.