Materials and Structures

, Volume 43, Supplement 1, pp 53–62 | Cite as

Bond behaviour of reinforcing bars in self-compacting concrete: experimental determination by using beam tests

Original Article

Abstract

The force transfer between concrete and reinforcement depends on the bond characteristics between the two materials. Bond influences crack widths and the deflections of RC members and also determines anchorage and splice lengths. Self-compacting concrete (SCC) is characterized by a smaller amount of coarse aggregates when compared to conventional vibrated concrete. To investigate whether this change in mix design has a significant influence on the bond behaviour, a series of beam tests (according to RILEM recommendation RC6) was performed. A total of 36 specimens were cast using 3 different concrete types: one conventional vibrated concrete (CVC) and two powder-type SCC’s. The bond stress—slip behaviour of reinforcing bars with diameters ranging from 12 to 40 mm has been recorded. From these tests, it can be concluded that the bond strength of SCC is even higher than it is for CVC for small bar diameters, but the difference becomes smaller for larger bar diameters.

Keywords

Self-compacting concrete Bond strength Beam test Reinforcement Bar diameter 

List of symbols

ϕ

Reinforcement bar diameter, mm

σs

Tensile stress in the reinforcing bar, N/mm2

τM

Characteristic value of the bond strength, N/mm2

τR

Ultimate bond strength, N/mm2

τR,n

Normalised ultimate bond strength, N/mm2

CVC

Conventional vibrated concrete

DEV

Standard deviation

fc

Concrete compressive strength, N/mm2

fccub

Concrete cube compressive strength, N/mm2

fct,fl

Concrete flexural tensile strength, N/mm2

fct,sp

Concrete splitting tensile strength, N/mm2

fR

Relative rib area of a reinforcing bar

fu

Ultimate tensile strength of a reinforcing bar, N/mm2

fy

Yield strength of a reinforcing bar, N/mm2

Fs

Total tensile force in a reinforcing bar, N

k

Bond length expressed as ‘times the bar diameter ϕ’

ld

Bond length, mm

P

Total load applied during the test, N

SCC

Self-compacting concrete

su

Slip corresponding to the ultimate bond strength, mm

Notes

Acknowledgements

The authors would like to acknowledge the Fund for Scientific Research in Flanders (FWO) for the financial support of the research project.

References

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Copyright information

© RILEM 2010

Authors and Affiliations

  • Pieter Desnerck
    • 1
  • Geert De Schutter
    • 1
  • Luc Taerwe
    • 1
  1. 1.Magnel Laboratory for Concrete Research, Department of Structural EngineeringGhent UniversityGhentBelgium

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