Fiberglass rebar vs steel rebar
Is fiberglass rebar cost-competitive against steel?
Fiberglass rebar is a cost-competitive material compared to coated steel. If corrosion is not an issue or non-metallic reinforcement is not required, then steel may be a suitable option. Based on life cycle cost analysis, the use of Mateenbar™ provides competitive prices, zero maintenance, excellent durability, and long design life. Using Mateenbar saves in these areas:
- Reduced concrete coverage – extra concrete thickness is not required to protect the rebar
- No allowances needed for diameter reduction caused by corrosion
- No expensive concrete waterproofing additives required
- No cathodic protection required
- Significantly cheaper than stainless steel
- Does not rely on surface protection like epoxy rebar, so does not need to be touched-up after placement
- Zero maintenance costs
- GFRP rebar is 75% lighter than steel – saves on freight, speeds up installation, and reduces labor requirements.
How does the modulus of Mateenbar™ compare to steel rebar?
The 60GPa range offers the designer a cost-effective solution. Steel has a tensile modulus of 200GPa.
How does the tensile strength of fiberglass rebar compare to steel rebar?
Mateenbar™ is one of the highest strength composite rebars available, with a tensile strength of over 1000 MPa. This is over twice the tensile strength of steel rebar, which is typically 400 to 500 MPa.
Fiberglass rebar performance
How can the lower modulus be allowed for in the design?
The lower modulus can be overcome as Mateenbar™ is corrosion-resistant. Large concrete coverage to provide protection is not required so fiberglass rebar can be placed closer to the surface. The increased distance from the neutral axis increases the sectional modulus.
Due to the non-corrosive nature of Mateenbar™ the crack-width allowance, as defined by ACI, is increased from 0.3mm to 0.7mm.
Can a higher modulus fiberglass rebar be manufactured?
The modulus of Mateenbar™ is over 60GPa, which is the theoretical limit for ECR glass-reinforced rebar. Other reinforcements can be used, such as carbon-fiber, aramid-fiber, or S-glass. However, all these reinforcement options are expensive.
Does fiberglass rebar have a ductile failure?
Fiberglass rebar is linear elastic to the point of failure, correct design methodology ensures the structure exhibits the desirable ductile failure mechanism. This is achieved by a balanced reinforcement design. The higher tensile strength of the reinforcement then forces a mechanism of progressive bond-failure, which results in a ductile failure mode of the structure. American Concrete Institute ACI 440 document provides further details.
Is Mateenbar™ affected by alkaline conditions?
Mateenbar™ is manufactured from a high-grade glass-fiber called ECR-glass. It is immune to alkaline attack.
Can mateenbar™ be bent on-site?
Mateenbar™ bends must be manufactured to shape at the factory. However, standard bend shapes are available.
Are bends as strong as straights?
As with steel and other rebar bends, the bent section of the GFRP rebar is not as strong as straights.
Working with fiberglass rebar
Are there any special handling requirements for fiberglass rebars?
Does on-site damage need to be repaired?
With any rebar, significant damage must be addressed. Minor damage will not affect the performance of mateenbar™ as it does not rely on any form of coating to protect from corrosive elements.
Do I need to design specifically for GFRP rebar?
You must design around the properties of GFRP rebar. The American Concrete Institute ACI 440 committee is an excellent source of information and designers should familiarise themselves with ACI 440.1R-06 or similar guides. Find out about the latest codes and standards for GFRP rebar here.
The Mateenbar™ team is on-hand to work with design engineers if they need assistance in transitioning from steel to Mateenbar™.
When should I use mateenbar™?
Mateenbar™ provides a corrosion-free rebar alternative with an extended asset lifespan in the most challenging and corrosive environments. If the issue of corrosion is present in any project, Mateenbar™ should be considered as a superior alternative to steel – eliminating the risk of corrosion and associated maintenance costs. It does not need protective coating or cathodic protection.
Mateenbar™ is non-metallic making it ideal for environments where conductivity poses a safety risk or interference to sensitive equipment. Mateenbar can be safely used in near MRI scanner in hospitals, light rail projects, airport compass calibration pads, and electrical substations.
What is the difference between GFRP and FRP rebar?
FRP stands for Fibre Reinforced Polymer, which encompasses other fibers such as basalt (BFRP) and carbon (CFRP).