Characterization and Design of a Crumb Rubber Modified Asphalt Mix Formulation

Authors: H. Al-Baghli

Abstract:

Laboratory trial results of mixing crumb rubber produced from discarded tires with 60/70 pen grade Kuwaiti bitumen are presented on this paper. PG grading and multiple stress creep recovery tests were conducted on Kuwaiti bitumen blended with 15% and 18% crumb rubber at temperatures ranging from 40 to 70 °C. The results from elastic recovery and non-recoverable creep presented optimum performance at 18% rubber content. The optimum rubberized-bitumen mix was next transformed into a pelletized form (PelletPave^®), and was used as a partial replacement to the conventional bitumen in the manufacture of continuously graded hot mix asphalts at a number of binder contents. The trialed PelletPave^® contents were at 2.5%, 3.0%, and 3.5% by mass of asphalt mix. In this investigation, it was not possible to utilize the results of standard Marshall method of mix design (i.e. volumetric, stability and flow tests) and subsequently additional assessment of mix compactability was carried out using gyratory compactor in order to determine the optimum PelletPave^® and total binder contents.

Keywords: Crumb rubber, Marshall mix design, PG grading, rubberized-bitumen.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.3669295

References:

[1] AASHTO T 315-12 (R2016), Standard method of test for determining the rheological properties of asphalt binder using a dynamic shear rheometer (DSR).
[2] AASHTO T 350-14, Standard method of test for multiple stress creep recovery (MSCR) test of asphalt binder using a dynamic shear rheometer (DSR).
[3] State of Kuwait, Ministry of Public Works (MPW) Specifications, QCS2014, Section 6- Road works, Part 5- Asphalt Works.
[4] Asphalt Institute, MS-2 Asphalt Mix Design Methods, ISBN: 9781934154700.
[5] G. Way, K. Kaloush, and K. Biligiri, Consulpav Int. and Arizona State University. Asphalt-Rubber Standard Practice Guide. Rubber Pavement Association (2012).
[6] M.D. Domingos, A.L. Faxina, Susceptibilty of asphalt binders to rutting: literature review, J. Mater. Civ. Eng., Vol. 28, Issue 2, (2016).