Dynamic properties of dense sand-rubber mixtures with small particles size ratio

Abstract

In this study, the small strain shear modulus G_max and the damping ratio D_min of sand–rubber mixtures with a small particles size ratio Sr (D_50rubber/D_50sand = .36) are characterised by shear wave propagation using bender elements inserted in a modified triaxial cell. The influence of addition of less than 50% rubber volume fractions Rf in a range of confining pressures varying from 50 to 500 kPa was investigated. The results showed that, for all confining pressures, the shear modulus decreases with increasing rubber volume fractions, while the damping ratio linearly increases. A quasi-conservation of shear modulus up to a volume fraction Rf = .2 and sharp decrease beyond this content is observed. The shear modulus decay and the damping enhancement with addition of rubber fractions are mitigated by increasing confining pressures. An optimal increase of the damping ratio without significant loss of rigidity and a minimal sensitivity to confining pressure for mixtures containing about 10% rubber is highlighted. The shear modulus and damping ratio are power function of the mean effective stress within the range studied.

Keywords:

• sand–rubber mixture
• shear wave
• bender elements
• triaxial cell
• shear modulus
• damping ratio

Acknowledgements

The experimental work described in this paper was carried out by Ali BRARA as part of his doctoral thesis at the laboratory LEM3 of Lorraine University of Metz. The experimental programme of this thesis (registered at the research unit URIE of Ecole Nationale Polytechnique) was carried out under the supervision of Dr Ali DAOUADJI during an 18-months stay funded by a grant awarded by the Algerian Ministry of Higher Education and Scientific Research. The PhD student expresses a deep gratitude to his supervisors and to the research institutions Directors (URIE, LEM3) for their assistance and hosting.

Disclosure statement

No potential conflict of interest was reported by the authors.