Experimental assessment of the tensile and shear strength behaviour of polyolefin fibre reinforced concrete

Abstract

In the last decades, certain types of non-metallic fibres have

been found suitable for structural concrete elements. Polyolefin

macro-fibres can meet the requirements set in the standards in

order to consider their contribution in the structural design.

Previous experimental campaigns carried out with polyolefin

fibre reinforced concrete (PFRC) have evaluated their flexural

fracture behaviour, with several amounts of fibre dosages.

Given that the structural requirements were set based on the

results obtained by following UNE-EN 14651:2007+A1 that

only considers the flexural behaviour, the contributions of

the fibres when the structural element is subjected to more

complex stress states is a matter that deserves further studied.

The main objective of this contribution is to assess the

performance of PFRC subjected to tensile stresses and shear

stresses, using low performance concrete and water/cement

ratio greater than the maximum indicated by the EHE-08,

that can be used in ground slabs, gutters and pipes, replacing

traditional reinforcement. This was carried out developing

uniaxial tensile tests and push-off tests. In order to do so, the

remaining halves of PFRC samples already tested following

UNE-EN 14651 were used. Two PFRC formulations were

studied, one with 6kg/m3 of fibres and another with 7.5kg/m3 of

fibres. In both cases 48mm-long fibres were added. These tests

were also recorded in order to analyse the damage patterns and

the appearance, growing and coalescence of cracks by means

of digital image correlations techniques.

Non-standardised test results showed a remarkable PFRC

behaviour both under tensile and shear stresses. Such results

confirmed the suitability of PFRC as a structural material.

In addition, the test results widened the knowledge of the

mechanical response of PFRC under complex stress states.