NMR on the Road: Non-destructive Characterization of the Crumb-Rubber Fraction in Asphalt

Abstract

Crumb rubber is used in asphalt to improve its long-term performance. Its fraction and distribution are key factors determining the quality of pavements with rubber-modified asphalt. It is shown how the rubber fraction and the heterogeneity of the pavement can be assessed non-destructively by single-sided NMR relaxometry with the NMR-MOUSE. The methodology employs laboratory-based calibration curves from reference samples and has been tested with field measurements on ten different roads. This work is the first of its kind and reports a significant step forward towards improved, non-destructive quality control of rubber-modified asphalt pavements.