An acoustic emission (AE) technique has been employed to study the low-temperature performance of styrene butadiene styrene (SBS) modified binders. Highly sensitive microphones in contact with the samples detect shock waves during cooling cycles with binders and asphalts. These shock waves are ascribed to crack initiation and/or propagation and the technique makes possible early monitoring of defects in binders and asphalts and comparative assessment of low-temperature performance. It is demonstrated that SBS modified binders perform better than their unmodified counterparts, also that the effectiveness of modification at low polymer levels depends on the compatibility of the bitumen/polymer blend. The performance of the asphalt mixes in restrained cooling as detected by acoustic emission could not be readily related to traditional, low-temperature characterisation tests such as the Fraass fracture test. The best correlation was obtained with the Hills single-glass-plate fracture test carried out on roughened glass. (A) The German title of this article is: Schallemission : ein neues Mittel für die Bewertung der Relativ-Kenngrössen von Bindemitteln und Asphalte bei Tiefen Temperaturen.
Abstract