Cyclic damage to PVA microfibre embedded in cementitious matrix in alternating tension-compression regime

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Contributors

Abstract

The structures subject to dynamic loading demand more ductile materials to prevent catastrophic failure. The results of investigations on strain-hardening cement-based composites (SHCCs) distinguished this group of materials - due to their highly ductile behaviour - as a suitable alternative for structures with high resistance against seismic, impact and cyclic loadings. While mechanical properties of SHCC are determined mostly by bridging behaviour of dispersed fibres crossing cracks and properties of fibre-matrix interface, the dependency of these mechanisms on the loading regime is pronounced. Specifically, under cyclic loading, the number of cycles to failure decreases dramatically when SHCC is subject to alternating tension-compression regime. Degradation of fibres compressed between the crack faces and deterioration of their bridging capacity are responsible for such early failure and necessitate further investigations at the micro level. The article at hand presents the influence of loading history in cyclic tension-compression regime on the bridging capacity of the single PVA microfibre embedded in cementitious matrix. A novel double-sided single fibre pull-out setup is used for the experimental investigations. First the test setup, material composition and testing procedure are explained. Next, the results of double-sided pull-out specimens, tested under monotonic and cyclic tension-compression regimes, are discussed. It is shown that the deterioration of fibre bridging capacity can be assessed by applying cyclic loading in post-cracking stage, followed by pulling the fibre out of the matrix. Possibility of a change in pull-out behaviour of PVA microfibre from "fibre rupture" to "fibre pullout", also a change of behaviour in post debonding regime from "hardening" to "softening" are also observed. Eventually, the results of microscopic analysis are presented and discussed, which show the specific phenomena responsible for changes in pull-out behaviour.

Details

Original languageEnglish
Title of host publicationFibre Reinforced Concrete
EditorsBruno Massicotte, Barzin Mobasher, Fausto Minelli, Giovanni Plizzari
PublisherAmerican Concrete Institute
Pages321-329
Number of pages9
ISBN (electronic)9782883941427
Publication statusPublished - 3 Nov 2020
Peer-reviewedYes

Publication series

Series ACI structural journal
Number3
Volume343
ISSN0889-3241

Conference

Title3rd ACI-fib-RILEM International Workshop on Fibre Reinforced Concrete: From Design to Structural Applications, FRC 2018
Duration28 - 30 July 2018
CityDesenzano
CountryItaly

Keywords

Keywords

  • Cement-based composites, Cyclic damage, Cyclic tensioncompression loading regime, Fatigue, Fibre pull-out test, PVA microfibre, SHCC