Modified digital image correlation aided measurement of the transverse to longitudinal deformation ratio for polymeric macro-fibres

Abstract

Considering the increasing interest of polymeric macro-fibres reinforced concrete, a simple and straightforward method to assess the fibre’s transverse to longitudinal deformation ratio (ηf) becomes a determining aspect in terms of fibre both characterization and fibre–matrix interaction optimization. A noncontact optical measurement procedure to assess this ratio (ηf) - for concrete reinforcement - by a modified 2D Digital Image Correlation method is presented in this paper. This ratio (ηf) has influence on the matrix-fibre interaction and, thus, on the post-cracking tensile response of the concrete composite. Details on the definition, implementation and validation of this measurement procedure are presented. Additionally, an experimental program on 20 selected lab grade and commercial fibres was carried out to analyse the consistency of the measurements and the influence of the fibre’s geometric characteristics (flat, curved, embossed or crimped) on the ηf. The outcomes of this research and the experimental procedure proposed are meant to assist fibre producers on the design process of optimized fibres to be used in structural concrete.

Keywords

• Poisson’s ratio
• Polymeric macro-fibre
• Concrete
• Fibre reinforced concrete
• DIC
• Deformation