Influence of confining pressure on rubberised cement bound aggregate behaviour during static triaxial test

Abstract

The aim of this research was to better understand the influence of adding waste rubber in cement bound aggregate (CBA) by testing both the unconfined and triaxial stress state. CBA with waste rubber was tested in this manner aiming to analyse influence of the confining pressure on the material behaviour. The results indicate that adding 20% rubber to a high cement content mix can assimilate the high stiffness caused by the high cement paste content, resulting in a mixture with increased cement paste content to facilitate in situ compaction. Additionally, a low confining pressure of 40 kPa has the most impact on the elastic properties/stiffness and it would be more appropriate to measure the CBA elasticity modulus with moderate lateral (confining) pressure. Finally, the practical implication of this research is that, in pavement mechanistic-empirical design, a correction of the measured uniaxial static modulus of elasticity by 10–15% should be adopted.

KEYWORDS:

• Pavement
• cement bound aggregate
• waste tyres
• static triaxial test
• confining pressure

Acknowledgements

The authors thank assist. prof. Tihomir Dokšanović for his help in static modulus of elasticity measurement by Aramis 3D measuring system, and acknowledge his contribution to this research.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research is supported and funded by Croatian Science Foundation under the project UIP-2019-04-8195 Cement stabilized base courses with waste rubber for sustainable pavements – RubSuPave.