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Arabian Journal for Science and Engineering

, Volume 36, Issue 7, pp 1221–1239 | Cite as

Combined Effect of Moisture and Temperature on Concrete Cover Surrounding GFRP Bars

  • Ali ZaidiEmail author
  • Radhouane Masmoudi
Research Article - Civil Engineering

Abstract

In the last decade, fiber reinforced polymer (FRP) has become the best solution to the problem of corrosion in reinforced concrete structures. However, more detailed investigation of the thermal behavior of FRP bars embedded in wet concrete is required to avoid splitting failure of concrete cover of reinforced concrete structures immersed in water under temperature. This paper presents an experimental study to investigate the combined effect of moisture and temperature on the behavior of FRP bar and concrete cover using concrete cylinder specimens reinforced with glass FRP (GFRP) bars immersed in water and subjected to temperatures varying from −30 to +80°C. The experimental results show that immersion in water at high temperature can damage the bond between GFRP bar and concrete. The temperatures required to produce splitting failure of concrete cover for concrete cover thickness to FRP bar diameter ratio (c/d b ) less than or equal to 1.5 immersed in water are between 50 and 60°C, similar to those for specimens not immersed in water. Also, moisture has no significant influence on the thermal behavior of concrete cover surrounding GFRP bar for temperatures up to 60°C. A comparison between the predicted and experimental transverse thermal strains is presented. The results show good agreement for temperatures up to 60°C.

Keywords

Fiber reinforced polymer Bars Combined effect Moisture Temperature Transverse thermal expansion Concrete cover 

List of symbols

a

Radius of FRP bar

b

Radius of concrete cylinder

c

Concrete cover thickness

D

Diameter of reinforced concrete cylinder specimen

db

Bar diameter

Ec

Modulus of elasticity of concrete

El

Longitudinal modulus of elasticity of FRP bar

Et

Transverse modulus of elasticity of FRP bar

\({f^{\prime}_{c28}}\)

Compressive strength of concrete

fct28

Tensile strength of concrete

ffu

Ultimate tensile strength of FRP bar

P

Radial pressure exerted by FRP bar on the surrounding concrete

r

Ratio of radius of cylinder to that of FRP bar rb/a

αc

Coefficient of thermal expansion of concrete

αt

Transverse coefficient of thermal expansion of FRP bar

αl

Longitudinal coefficient of thermal expansion of FRP bar

ΔT

Temperature increase (thermal load)

ΔTcr

Thermal load producing the first cracks in concrete at the FRP bar/concrete interface

ΔTsp

Thermal load producing splitting failure of concrete cover

\({\varepsilon_{ft}}\)

Transverse thermal strain of FRP bar

\({\varepsilon_{ct}}\)

Transverse thermal strain of concrete

νc

Poisson’s ratio of concrete

νtt

Transverse Poisson’s ratio of FRP bar

νlt

Longitudinal Poisson’s ratio of FRP bar

σρ

Radial stress in concrete

σt

Circumferential stress in concrete

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Copyright information

© King Fahd University of Petroleum and Minerals 2011

Authors and Affiliations

  1. 1.Department of Civil EngineeringLaghouat UniversityLaghouatAlgeria
  2. 2.Department of Civil EngineeringUniversity of SherbrookeSherbrookeCanada

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