Importance of Elastic Recovery in the DSR for Binders and Mastics

Elastic Recovery (ER) is used by many highway agencies for modified bitumen grading specifications. The current ASTM/AASHTO standards for ER testing utilize the ductility bath as the measurement apparatus. A new procedure for measuring the elastic recovery in the Dynamic Shear Rheometer (ER-DSR) was developed and was used to test different polymer modified binders and mastics. The results show a good correlation between the ER-DSR and ER measured in the ductility bath (ER-DB). The ER-DSR requires less material and is more time efficient and repeatable than the ER-DB. Since the link between the ER measurements and pavement performance is not well established, the study compared ER measurements with binder rutting and fatigue results as measured by the Multiple Stress Creep and Recovery (MSCR) test and the linear amplitude sweep (LAS) test, respectively. Generally, binders and mastics with higher ER-DSR value showed higher percent recovery (MSCR) and fatigue resistance (LAS). This study also showed the effect of natural and manufactured fillers on the percent recovery measured with the MSCR test. Based on the experimental results, it is recommended to replace ER-DB with the ER-DSR. Also, agencies should consider the MSCR and fatigue tests as indicators of binder modification rather than the ER, as they provide direct measurements of damage resistance characteristics for which the elastic recovery might not indicate

Collaboration checklist for creative robots

Through collaboration, Science, Engineering, and Art can create striking Human-Robot Interaction performance pieces, pushing technological and artistic boundaries to explore, educate, and challenge one’s understanding of HRI. However, the processes for creating a performance piece are often under discussed. This paper documents a collaborative effort to create a virtual performer, reflects on interdisciplinary work, and offers guidance for those considering such an endeavour

Relationship between binder and mixture damage resistance at intermediate and low temperatures

The importance of binder performance on the mixture response to accelerated fatigue loading and thermal cracking was investigated. Binder’s fatigue performance was measured by means of the Linear Amplitude Sweep test (LAS) while fatigue properties of the mixtures were investigated by performing the EBADE test. The low temperature properties of the binders were investigated by measuring the glass transition temperature and fracture properties with the Single Edge Notched Beam (SENB) test. The mixtures fracture properties were investigated using the FENIX test. The experimental matrix for this study included unmodified and rubber-modified binders and limestone aggregates. A good correlation between binder and mixture fracture energy was observed at low temperatures. This good correlation indicates the importance of fracture response of the binder to the overall low temperature cracking performance of the mixture. Experimental results suggest that a significant part of the variation of the fracture energy of the mixture can be explained by the binder fracture properties. Good correlations were also obtained for the displacement at maximum load in the SENB and Fenix tests. Similar accelerated fatigue response for binders and mixtures were observed when the stresses and strains were normalized. Significant reduction in the stress happened at about the same normalized strain in the binder and mixture. It can be seen that the mixture has remaining strength after reaching peak stress probably due to the aggregate structure.Postprint (published version

Relationship between binder and mixture damage resistance at intermediate and low temperatures

The importance of binder performance on the mixture response to accelerated fatigue loading and thermal cracking was investigated. Binder’s fatigue performance was measured by means of the Linear Amplitude Sweep test (LAS) while fatigue properties of the mixtures were investigated by performing the EBADE test. The low temperature properties of the binders were investigated by measuring the glass transition temperature and fracture properties with the Single Edge Notched Beam (SENB) test. The mixtures fracture properties were investigated using the FENIX test. The experimental matrix for this study included unmodified and rubber-modified binders and limestone aggregates. A good correlation between binder and mixture fracture energy was observed at low temperatures. This good correlation indicates the importance of fracture response of the binder to the overall low temperature cracking performance of the mixture. Experimental results suggest that a significant part of the variation of the fracture energy of the mixture can be explained by the binder fracture properties. Good correlations were also obtained for the displacement at maximum load in the SENB and Fenix tests. Similar accelerated fatigue response for binders and mixtures were observed when the stresses and strains were normalized. Significant reduction in the stress happened at about the same normalized strain in the binder and mixture. It can be seen that the mixture has remaining strength after reaching peak stress probably due to the aggregate structure