119: Shrinkage cracking of steel fibre reinforced self compacting concrete overlays test methods and theoretical modelling

Title: 119: Shrinkage cracking of steel fibre reinforced self compacting concrete overlays test methods and theoretical modelling
Author(s): J. Carlswärd, M. Emborg
Paper category : conference
Book title: 5th International RILEM Symposium on Self-Compacting Concrete
Editor(s): G. De Schutter and V. Boel
Print-ISBN: 978-2-35158-047-9
e-ISBN: 978-2-35158-088-2
Publisher: RILEM Publications SARL
Publication year: 2007
Pages: 793 - 798
Total Pages: 6
Nb references: 1
Language: English

Abstract: The cracking response of bonded SCC overlays with and without steel fibres exposed to restrained shrinkage has been assessed. Test results showed that steel fibres may provide a significant contribution in regard to crack width limitation. However, the amounts of steel fibres considered in the study (up to 60 kg/m3 of an end-hooked steel fibre) did not offer sufficient resistance so as to distribute cracks in situations when bond to the substrate was low or non-existent (internally de-bonded overlays). For overlays with sufficient bond, on the other hand, a well distributed pattern of fine cracks were observed both for un-reinforced concrete as well as for steel fibre reinforced SCC, i.e. reinforcement is not required to control shrinkage cracking for thin overlays (50 mm in the tests) if high bond strength is achieved. Bond tests verified that roughening the substrate is not essential for high bond strength to develop. Results rather implied that concrete-to-concrete bond is controlled by the moisture exchange at the interface between overlay and substrate.
An analytical model was further developed to assess the risk of cracking and to predict crack widths of SFR-SCC overlays. The model was shown to give rather good correlation with experimental results.

Online publication: 2009-06-16
Publication type : full_text
Public price (Euros): 0.00