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Toward more realistic viscosity measurements of tyre rubber–bitumen blends

Lo Presti, Davide; Fecarotti, Claudia; Clare, Adam T.; Airey, Gordon


Davide Lo Presti

Claudia Fecarotti

Adam T. Clare

Professor of Pavement Engineering Materials


The measurement of rheological properties of the tyre rubber bitumen blends is often challenging due to presence of suspended tyre rubber’s crumbs. Furthermore, the phase separation during the course of measurements makes the viscosity of these non-homogeneous blends difficult to ascertain. In this study, a new dual helical impeller was designed and manufactured to be used with a rotational viscometer in order to have a real-time control of the viscosity while performing a laboratory mixing of the blends. Layer based manufacturing techniques showed to be a convenient method to produce complex shaped impeller prototypes before manufacturing the more expensive stainless steel assembly. Impeller geometry was optimised to create a convective like flow within the sample and so minimise phase separation. Shear rate constant is geometry dependent and a calibration exercise was carried out to ascertain this. Results of both calibration and validation phases showed that the new impeller provides reliable viscosity measurements of homogenous fluids such as neat bitumen. With regards to complex fluids the new impeller showed a more stable and realistic trend than that obtained by using a standard spindle. In fact, it was demonstrated that the new impeller significantly decreases phase separation within the blend and in turns provides a more realistic measurement of the viscosity. This system represents a feasible and improved solution for optimising the laboratory modification process of tyre rubber bitumen blends by adapting the rotational viscometer as a low-shear mixer.


Lo Presti, D., Fecarotti, C., Clare, A. T., & Airey, G. (2014). Toward more realistic viscosity measurements of tyre rubber–bitumen blends. Construction and Building Materials, 67, 270-278.

Journal Article Type Article
Acceptance Date Mar 25, 2014
Online Publication Date Apr 13, 2014
Publication Date 2014-09
Deposit Date May 12, 2014
Publicly Available Date Sep 19, 2019
Journal Construction and Building Materials
Print ISSN 0950-0618
Electronic ISSN 0950-0618
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 67
Pages 270-278
Public URL
Publisher URL
Copyright Statement Copyright information regarding this work can be found at the following address:
Additional Information This article is maintained by: Elsevier; Article Title: Toward more realistic viscosity measurements of tyre rubber–bitumen blends; Journal Title: Construction and Building Materials; CrossRef DOI link to publisher maintained version:; Content Type: article; Copyright: Copyright © 2014 The Authors. Published by Elsevier Ltd.


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