Polypropylene fibre reinforcement of hardened cement paste

Gandhi, D

Abstract

This thesis considers the tensile deformation characteristics of
polypropylene fibre reinforced hardened cement paste having heterogeneous
fibre geometries and a range of volume concentrations.
Polypropylene fibres were prepared under various manufacturing
conditions using a laboratory extruder, to ascertain the effect of
these conditions on fibre characteristics.
The relevant properties of cement paste likely to influence the
polypropylene fibres and the eventual composite were investigated.
An investigation of continuous aligned fibre composites in tension,
containing various volume concentrations of fibres, showed that
multiple cracking occurred despite the elastic modulus of the fibre
being considerably lower than that of the hardened cement paste.
Factors which enabled fibre/matrix contact to be maintained during
the multiple cracking process, despite the unfavourable Poisson's
ratio of polypropylene, were considered.
Discontinuous aligned fibre composites were tested in tension, to
ascertain the effect of volume concentration and length of fibres on
the shear stress transfer between fibre and matrix and on multiple
cracking.
Composites containing parallel fibres, with fibre directions at
varying angles to the direction of applied tensile stress, allowed
an assessment to be made of the role of inclination. Crack
distributions, pull-out behaviour of fibres and the ultimate stress
of composites were investigated.
Finally, random fibre reinforced composites were evaluated to provide
a comparison with the Continuous, Discontinuous and Inclined fibre
reinforced systems.
In addition to determining the mechanical deformation of the various
composites, the acoustic emission associated with internal deformation
mechanisms was studied. This was undertaken with equipment capable
of monitoring a range of acoustic pulse parameters.

Citation

Gandhi, D. Polypropylene fibre reinforcement of hardened cement paste. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Sep 23, 2011
• Publicly Available Date: Sep 23, 2011
• Award Date: Jan 1, 1982