Influence of processing conditions on the rheological behavior of crumb tire rubber-modified bitumen

• Published in: Journal of applied polymer science Vol. 104; no. 3; pp. 1683 - 1691
• Main Authors: Navarro, F. J., Partal, P., Martínez-Boza, F. J., Gallegos, C.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 05-05-2007; Wiley
• Subjects: Applied sciences; asphalt; binder; Bitumen. Tars. Bituminous binders and bituminous concretes; Buildings. Public works; crumb rubber; Exact sciences and technology; Materials; modified bitumen; Polymer industry, paints, wood; rheology; stability; Technology of polymers; Waste treatment; Viscoelasticity; modified bitumen; Scrap rubber; Mixing; rheology; Elastomer; Temperature effect; Natural rubber; asphalt; Experimental study; Property processing relationship; Tyre; Structure processing relationship; Polymer modified asphalt; Shear viscosity; Vulcanizate; Storage stability; crumb rubber; Morphology; Concentration effect; Waste reuse; binder; stability; Rheological properties
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.25800

Traditional or technological studies about crumb tire rubber‐modified bitumens (CTRMBs) do not provide detailed rheological information. In that way, this article describes the influence of processing conditions on the linear viscoelastic and viscous behaviors of CTRMBs. The results of the study reveal an exponential increase in dissolved/dispersed rubber with processing temperature and, therefore, lower solid content that affect the rheological behavior in different ways. No influence of the processing device was observed, probably due to the fact that processing temperature (180°C) was not high enough to break up the crosslinked network of the rubber. The presence of rubber particles avoids the negative hardening effects observed for unmodified bitumens, resulting in a more flexible binder at low temperature. At high in‐service temperature, better rutting resistance would also be expected for CTRMBs. Flow results at 135°C indicates that modified bitumens can satisfy the AASHTO MP1 requirements if high‐enough shear rates are reached. All the CTRMBs studied present segregation, due to rubber settling during storage at high temperature, although an increase in processing temperature seems to enhance its stability. The results obtained seem to indicate that the optimum CTRMB processing temperature is 210°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1683–1691, 2007