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15. Cementitious composites with high tensile strength and ductility through hybrid fibres



Title: 15. Cementitious composites with high tensile strength and ductility through hybrid fibres
Author(s): J.G.M. van Mier
Paper category : conference
Book title: 6th International RILEM Symposium on Fibre Reinforced Concretes
Editor(s): M. di Prisco, R. Felicetti and G.A. Plizzari
Print-ISBN: 2-912143-51-9
e-ISBN: 2912143748
Publisher: RILEM Publications SARL
Publication year: 2004
Pages: 219 - 236
Total Pages: 18
Nb references: 29
Language: English


Abstract: Increasing the tensile strength and ductility is the aim of hybrid fibre concretes (HFC). Actively interfering with the microcrack process and with macrocrack growth is required to achieve these goals. The addition of fibres resembles the use of external active confinement. The fibre cocktails must be selected such that (1) the microcrack length is minimized as long as possible, and (2) the bridging of the cracks must be such that no sudden large deformations develop during (macro) crack growth. The fibres must effecti-vely withstand loss of load carrying capacity from the concrete itself. Finally the mixtures must be self-compacting to ensure that proper fibre distributions are obtained. Nevertheless since structural shape and flow properties of the mixtures determine the ultimate fibre distribution, standard test methods must be designed so that the material is tested as it appears in the structure. HFC seems particularly suitable for the pre-cast concrete industry, where the higher demands for quality control can be met. Optimization of the placement of the material in structures with given shape may lead to the best structural behaviour, while minimizing the use of the material. Examples of applications are long-span lightweight girders, sheet-piling, etc. Reducing conventional (and expensive) steel reinforcement can be achieved. Moreover, since HFC displays a clear hardening behaviour, the widths of cracks are very small, which positively affects durability. The high cement content is a favourable factor in this respect as well, since self-healing of microcracks can help to ensure durability for extended periods.


Online publication: 2004-08-30
Publication type : full_text
Public price (Euros): 0.00