Title:
Reduction of Flexural Crack Widths Using Synthetic Fibres in Reinforced Concrete
Author(s):
Bernard, E. S.
Publication:
Symposium Paper
Volume:
343
Issue:
Appears on pages(s):
331-340
Keywords:
Crack width, fibre reinforced concrete, post-crack performance, flexure, tension stiffening, conventional reinforcement
DOI:
Date:
10/1/2020
Abstract:
The use of steel fibres to reduce the width of flexural and tensile cracks in reinforced concrete members is now well recognised and aspects of this phenomenon have been incorporated into several codes internationally. Almost all the research work upon which this
has been based has involved hooked-end steel fibres, with very little work undertaken using other types of fibre. However, the theories underlying how fibres assist in reducing crack widths are not specific to hooked-end steel fibres, so alternative types of fibre could work in a similar way to reduce crack widths in flexural and tensile members.
The current paper outlines work recently completed on the effect of several types of synthetic fibre on flexural crack widths in reinforced concrete members. The fibres have predominantly been manufactured using polypropylene, but other materials including
aramide, nylon and PVA can also be used for this purpose and have been included in this investigation. Laboratory testing has demonstrated that synthetic fibres are fully capable of reducing flexural crack widths, but their efficacy is not consistent across all fibre types and designs. Testing appears to demonstrate that for a given dosage rate of fibre, the capacity of a FRC mix to limit flexural crack widths is related to the post-crack residual strength. However,
some fibres can limit crack widths more effectively than is predicted by existing expressions for design width that are based primarily on post-crack residual strength. This suggests that post-crack toughness is not the only parameter contributing to crack width reduction in
Reinforced Concrete members.
Related References:
Abrishami, H. H., and Mitchell, D., 1997. “Influence of Steel Fibres on Tension Stiffening,” ACI Structural Journal, 94(6) pp769-776.
AS/NZS 4671: 2001 Steel Reinforcing Materials, Standards Australia, Sydney.
Australian Standard AS3600, 2014. Concrete Structures, Standards Australia, Sydney.
Australian Standard AS3600, 2014 Concrete Structures, Commentary, Standards Australia, Sydney
Bernard, E.S., 2016. “Investigation of Crack Width Control Using Barchip Macro-synthetic Fibres in Reinforced Concrete Beams”, World Tunneling Congress 2016, San Francisco, April 22-28.
Bischoff, P. H., 2003. “Tension Stiffening and Cracking of Steel Fibre-Reinforced Concrete,” Journal of Materials in Civil Engineering, ASCE, 15(2), pp. 174-182
Conforti, A., Zerbino, R., and Plizzari, G.A., 2018. “Influence of steel, glass and polymer fibers on the cracking behavior of reinforced concrete beams under flexure”, Structural Concrete, 1-11. doi: 10.1002/suco.201800079
Deluce, J.R., Lee, S-C., and Vecchio, F.J. 2014, “Crack Model for Steel Fibre-Reinforced Concrete Members Containing Conventional Reinforcement”, ACI Structural Journal, 111(1) pp93-102.
Dupont, D., and Vandewalle, L., 2003, “Calculation of Crack Widths with the σ-ε Method,” Test and Design Methods for Steel Fibre Reinforced Concrete: Background and Experiences, Proceedings of the RILEM TC162-TDF Workshop, RILEM Technical Committee 162-TDF, Bochum, Germany, pp119-144.
Eurocode 2, 2004. Design of Concrete Structures, British Standard BS EN 1992-1-1:2004, European Committee for Standardisation (CEN).
fib, 2012. Model Code 2010, Bulletin 65, Fèdération Internationale du Béton, Lausanne Gilbert R.I. and Bernard, E.S., 2015. “Time-dependent Analysis of Macro-synthetic FRC
Sections with Bar Reinforcement”, World Tunneling Congress 2015, Dubrovnik, May 22-28.
Gilbert R.I., Mickleborough, N.C. and Ranzi, G., 2017. Design of prestressed concrete to Eurocode 2, Second Edition, CRC Press (Spon Press), Florida.
Jansson, A., Gylltoft, K., and Löfgren, I, 2010. “Flexural behaviour of members with a combination of steel fibres and conventional reinforcement”, Nordic Concrete Research, (42) pp155–171.
Tiberti, G., Minelli, F., Plizzari, G.A., and Vecchio, F.J., 2014. “Influence of concrete strength on crack development in SFRC members”, Cement & Concrete Composites, 45, pp176-185.
Vandewalle, L., 2000. “Cracking behaviour of concrete beams reinforced with a combination of ordinary reinforcement and steel fibres”, Materials and Structures, 33, pp164-170.