WHY GFRP REBAR & NOT STEEL

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Composite rebar, glass fiber reinforced polymer (GFRP) reinforcement bar is the solution to corrosion of reinforced concrete structure. Fiberglass Rebar is an excellent replacement for conventional types of steel rebar & here is why? 

 

Limitation with Steel rebar: 

 

  • Heavy (Increase logistic cost as well as adding more weight to the structure which affects the natural frequency of concrete structure)  

  • Corrosive (Even Stainless-Steel rust while it is 2 to 4 times more expensive than GFRP)

  • Very high stiffness (Structure becomes very stiff & rigid) 

  • Very limited fatigue resistance (Cyclic loading

  • High thermal & electrical conductivity 

  • Very high maintenance fee for Black-steel, Galvanized & Epoxy-coated rebar

  • more?!!!

 

 

MST-BAR® & MFX-BAR® GFRP rebar, composite rebar, fiberglass rebar is very suitable to use in the applications where steel rebar is limited to its properties. Where corrosion is a problem such as in a humid, coastal & cold countries ,MST-BAR® & MFX-BAR® can be used to take away the corrosion problem and all the costs associated with corrosion and maintenance. 

 

The initial cost of using MST-BAR® & MFX-BAR® at early stage of the project may not increase the cost of the project if a proper design and factors are to be considered. Using GFRP rebar may reduce the cost of the project up to 5% & the structure does not rquire any major maintenance for next 100 years. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MST-BAR® & MFX-BAR® GFRP rebar solve the limitation of steel bar by:

 

  • Light weight ( x4 lighter) 

  • Milder stiffness compare to steel (allows structures to be less rigid)

  • Thermal and electrical isolated 

  • 100% corrosion resistance to alkalis and acidic environment

  • Zero maintenance for 100 years  

 

 

DESIGN CODE

 

FRP Rebar does not behave in the same manner as steel rebar because the mechanical properties are different in some cases. FRP rebar has higher strength but lower elastic of modulus, therefore direct replacement of steel is not always possible with FRP rebar and FRP design codes required.

Following design codes required in design with FRP rebar:

Canada

CSA

  • CAN/CSA-S6-06(Canadian highway bridge design code)

  • CAN/CSA-S806-02(Design and construction of building component with FRP)

ISIS

  • Design Manual NO.3 (reinforcement concrete structure with FRP)

  • Design Manual NO.5 (Prestressing concrete structure with FRP )

USA

ACI

  • ACI 440.1R-06

  • ACI 440R-07

  • ACI 440.5-08

  • ACI 440.6-08

  • AASHTO GFRP-1

 

CORROSION OF REBAR
REBAR CORROSION
BRIDGE CORROSION
CORROSION
RUSTED REBAR

In the videos above we have seen MST-BAR went up to 250kN vs. Steel rebar came off the concrete at 78kN but Why?

  • MST-BAR does not change it cross sectional area when subjected to tensile 

  • Poisson ratio is very low in MST-BAR 

  • MST-BAR integral ribs bond so well to Cementous material 

How can we take advantage of this?

  • Avoiding extra fabrication and creating hooks or L-Bar

 

In order to prevent steel rebar to slip off the concrete you will need to create anchorage which often in steel rebar means bending the tail of the bar in to a hook form or L-Shape. 

With MST-BAR #5 (15mm) with embedment length of 100-120mm you can achieve 160kN(36000 lbf) of pullout force capacity which is about 65% higher than yield strength of steel rebar. This means straight MST-BAR can have 65% higher capacity than fabricated bended piece of steel bar. 

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