Behaviour of fibre reinforced cemented sand at high pressures

-, Salah-ud-din (2012) Behaviour of fibre reinforced cemented sand at high pressures. PhD thesis, University of Nottingham.

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Abstract

Several well established techniques of soil stabilisation and soil reinforcement are available to improve properties of geotechnical materials. However, the addition of fibre into soils has its unique potential as a reinforcing agent. This is because a friction between fibre and soil particles increases the bonding between the particles of soils and this can improve the plasticity, stress-strain behaviour and failure characteristics of both cemented and uncemented soils. It also reduces the brittleness of the cemented sand. Numerous experiments on fibre-reinforced granular materials have been carried out by several researchers. However, the behaviour of fibre-reinforced cemented granular soils has not been fully understood yet. Furthermore, most experimental studies of fibre reinforced cemented materials have been carried out at relatively low confining pressures. As a result, more experiments are still needed to understand complicated behaviour of soil-cement-fibre composite materials. The main objective of this thesis is to analyse the behaviour of fibre reinforced cemented sand under wide range of confining pressures.

For this GDS high pressure triaxial cell apparatus and Bishop and Wesley conventional triaxial cell apparatus have been used to carry out the tests at wide range of confining pressures from 50kPa to 20MPa. Drained and undrained tests have been carried out on polypropylene fibre reinforced sand with and without the addition of cement. Samples with varying fibre and cement content were prepared by the method of undercompaction and were cured for 28 days prior to testing.

The experimental results indicate that there is a significant effect from the addition of fibre and/or cement contents and confining pressures on the mechanical behaviour of Portaway sand. Particularly, these effects were noted in drained and undrained triaxial tests, particularly peak strength, strength parameters, shear banding, particle crushing, yielding, and stress-dilatancy relationships. The addition of fibres increases the peak, yield, and ultimate strengths. Increase in confining pressure also increases the strength but the individual effect of the addition of fibres was more pronounced at low confining pressures. Progressive suppression in the dilation by the gradual increase in confining pressures as well as an increase in dilation with the addition of fibres during triaxial compression was also worth noticeable. Although, no noticeable affect was observed in isotropic compression due to the addition of fibre in both cemented and uncemented sand. An extensive series of tests were carried out but due to time constraint only one type and length of fibre was used. Therefore, more research needs to be carried out at different fibre lengths and types in order to see that whether these change the behaviour observed in this research.

Item Type:Thesis (PhD)
Supervisors:Wanatowski, D.
Hall, M.
Faculties/Schools:UK Campuses > Faculty of Engineering > Department of Civil Engineering
ID Code:2545
Deposited By:Mr Salah-ud-din -
Deposited On:31 Oct 2012 14:17
Last Modified:31 Oct 2012 14:17

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