Structural performance of fibre-reinforced concrete columns

Authors: P. Paultre, R. Eid
Paper category: conference
Book title: Concrete Durability and Service Life Planning – ConcreteLife’09
Editor(s): K. Kovler
Print ISBN: 978-2-35158-074-5
e-ISBN: 978-2-35158-085-1
Publisher: RILEM Publications SARL
Publication year: 2009
Pages: 351 – 358
Total Pages: 8
Language: English

Abstract: The use of high-strength concrete (HSC) is continuously increasing due to its mechanical and durability advantages over normal-strength concrete (NSC). In high-rise buildings, HSC can reduce the dimensions of the lower stories columns, which makes it a better cost-effective choice for constructors than the NSC. The brittle behaviour of HSC under compressive loading, however, is the main reason for the slow acceptance of this material by concrete design codes. Moreover, it was shown that the confinement provided to HSC is less effective than in NSC and, therefore, a higher degree of confinement is required for HSC columns in order to achieve a similar ductility enhancement. Inclusion of short discrete fibres into the concrete mixture can increase the compressive strength and ductility of NSC and HSC column specimens under compressive loading as already has been shown by several studies. Concrete design codes ensure ductile behaviour of columns by setting a requirement for a minimum amount of transverse steel reinforcement. Therefore, the inclusion of discrete short fibres into the concrete mixture combined with a reduced amount of lateral reinforcement can be an alternative to the latter full amount required by the codes. Moreover, the higher resistance to crack growth and the excellent durability of fibre-reinforced concrete (FRC) over nonfibrous concrete can result in higher cost-effective value. This paper presents tests that were performed on large-scale fibre-reinforced normal- and high-strength concrete square and circular columns under concentric compression loading and under cyclic flexure and constant axial load simulating earthquake loading. The aim of this test program is to examine the combined confinement effect of steel or synthetic fibres and transverse steel reinforcement on the structural performance of NSC and HSC columns. The results show that in terms of ductility and energy dissipation, the behaviour of the FRC specimens is improved compared to the nonfibrous columns. The test results also show that the addition of discrete fibres to the HSC mixtures in reinforced concrete columns can prevent the premature spalling of the concrete cover and increase the strength and ductility of these columns. This behaviour is also predicted by the proposed confinement model which takes into account the mechanical and the geometrical properties of the concrete and the reinforcement as well as those of the fibres. Predictions were found to be in good agreement with experimental results.

Online publication: 2012-05-16
Publication Type: full_text
Public price (Euros): 0.00