Mechanical and elevated temperature performance of concrete incorporating surface-treated coarse tyre rubber aggregates

Alhamdan, Ahmad, Gardner, Diane ORCID: https://orcid.org/0000-0002-2864-9122 and Maddalena, Riccardo ORCID: https://orcid.org/0000-0001-6251-3782 2026. Mechanical and elevated temperature performance of concrete incorporating surface-treated coarse tyre rubber aggregates. Next Materials 13 , 103133. 10.1016/j.nxmate.2026.103133

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Abstract

The incorporation of coarse tyre rubber (CTR) in concrete offers a practical route for diverting end-of-life tyres from disposal and reducing natural aggregate demand. However, weak bonding at the rubber–paste interfacial transition zone can limit mechanical performance. This study evaluated 5–20% volumetric replacement of natural coarse aggregate with CTR under three distinct conditions: untreated concrete at 28 days, untreated concrete after exposure to 300 °C, and concrete containing cement-coated CTR at 28 days. The coating was produced by dry pelletisation with controlled water misting, without chemical pre-treatment. Increasing untreated CTR content reduced strength and stiffness but broadened the flexural load–displacement response, indicating greater deformation capacity and less brittle failure. Heating reduced the compressive, tensile, and flexural strengths of untreated mixes by 8.9–12.9%, 5.8–7.8%, and 3.6–9.8%, respectively, while mass loss remained below 3.3%. At 5%, 10%, 15%, and 20% CTR, coating increased compressive strength by 5.5%, 8.8%, 12.1%, and 16.1%, respectively, and flexural strength by 9.7%, 17.1%, 20.4%, and 24.0%, respectively; tensile strength increased by up to 16.8%. SEM observations showed interfacial gaps around untreated CTR, greater separation and microcracking after heating, and a more continuous interface after coating. The results demonstrate that dry cement coating partially recovers the mechanical performance of CTR concrete by improving interfacial load transfer, providing a simple treatment for non-structural and deformation-tolerant applications.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Engineering
ISSN:	2949-8228
Date of First Compliant Deposit:	24 August 2026
Date of Acceptance:	9 August 2026
Last Modified:	24 Aug 2026 11:18
URI:	https://orca.cardiff.ac.uk/id/eprint/189141

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