Effect of short fibre reinforcement on the yielding behaviour of cement-admixed clay

Abstract

This paper presents an experimental study on the effect of polypropylene fibres on the yielding behaviour of cement-admixed soft marine clay. A range of mix ratios is investigated, with the cement content spanning from 20% to 100%. The unconfined compression strength is first examined, followed by isotropic compression and subsequently shearing in triaxial stress conditions. These experimental results are analysed in comparison with unreinforced cement-admixed clay. A three-yield point framework, comprising of the first yield, gross yield and final yield points, is proposed to describe the evolution of the yielding process. The experimental data shows that fibre reinforcement has a greater effect on the size rather than the shape of the yield loci. The volumetric strain of the unreinforced cement-admixed clay matrix has a significant influence on the effectiveness of the fibre reinforcement under isotropic compression, which can be used as a measure of the size of the yield loci. The broad trends of behaviour highlighted in this paper are envisaged to be of use in the construction of constitutive models for fibre-reinforced cement-treated clay.