Steel is a material that is widely used in almost all areas of engineering – in infrastructure, industrial, mechanical, civil applications. It has high strength and is a very reliable material, so why would we replace the modern applications of steel with the Fibre reinforced polymer materials we have available to us to day. Whilst there are many areas in which steel excels as a material, it also has a variety of drawbacks that make in not suitable to some systems, and due to FRPs ability to work with a wide range of additives to change properties.

Steel is very susceptible to corrosion and hence to failure. Oxidation and chemical corrosion are big issues for steel, and hence reduce the amount of applications that steel can be used in, especially in systems with even small risk of exposure. FRP has a resistance to a wide range of chemical and effluent and is unaffected by moisture of immersion into water making it perfect for applications in marine or chemical circumstances. Unlike steel and aluminium, which are susceptible to oxidation and corrosion, FRP is able to withstand these chemicals and makes it the perfect applications in situations of water storage or treatment. Whilst treatment is available to strengthen steel, these treatment processes can sometimes be expensive and reduce the sustainability of steel. The additives to FRP are much simpler and easier to add making it a more cost effective material for applications with corrosion and oxidation risk. Additives to FRP are also able to make its properties alter, adding stronger corrosion resistance, flame retardants and temperature resistance.

Pound to pound, FRP is actually a stronger material than steel, making it a much stronger system whilst maintaining being a very lightweight material. Hence FRP is able to maintain its high strength whilst being a very lightweight material. This means two further advantages of FRP over steel appear. Firstly FRP systems are much more lightweight than steel making it much easier to install, which has a large amount of time savings and hence cost reduction. The second point is that pound for pound, FRP is actually stronger than steel. This can mean a wide range of advantages in the construction industry, allowing for frp to be used instead of steel and being able to maintain strength whilst able to reduce weight and also cost. It also hence has a greater strength in tensile and compression as well as in shear due to the addition of fibres for added strength.

Price is probably one of the most important considerations when comparing materials for projects. When we compare these two, steel has a lower initial material cost, this is true. But when we consider a wider range of expenses over the life of the system, FRP becomes much more affordable and economically efficient when compared to steel. It has lower installation costs due to its weight, much less maintenance require and a much longer life span all contributing to a cheaper overall cost over time.

Impact resistance is another property that varies when steel is compared to FRP. FRP as a whole will not permanently deform under a working load. The matrix material distributes impact load to prevent surface damage even in low temperatures whereas steel and other metals such as aluminium deform much easily under working load creating failure where FRP would not.

The other difference between the two is their thermal and electrical conductivity. Steel has high conductivity of both heat and electricity, providing good and bad advantages. FRP however have low thermal conductivity and zero electrical conduction making them perfect for applications where this property is desired. Hence FRP becomes more suitable to more applications in manufacture and construction having the ability to function normally at high temperatures and at sub zero temperatures. With varying thermal energy steel has  a much greater fluctuation of its properties, causing it to become more unreliable in varying temperatures, whereas FRP retains its reliability and properties in varying temperature conditions.

Finally when we compare its ease of fabrication and manufacture, a large disparity appears. FRP composites can be field fabricated using a simple carpenters tooling with no welding or torches required. It is also much easier to fabricate into intricate and complex shapes with much greater ease when compared to steel. Steel often requires welding and cutting torches, with the material requiring special equipment to erect and install.

FRP comparison to Generic Materials
PROPERTY FRP COMPOSITES STEEL ALUMINIUM
CORROSION RESISTANCE Resists a broad range of chemicals and unaffected by water – Protector Uses a smooth corrosion resistant barrier and a waterproof exterior layer Subject to oxidation and corrosion which otherwise requires galvanisation for many complications – a expensive and difficult process. Can cause galvanic corrosion
STRENGTH Gram for Gram stronger than Steel and aluminium

Compressive strength – 206.5MPa (LW)

Flexural Strength – 206.5MPa (LW)

 

Yield Strength – 248.22MPa

Higher tensile strength and higher tensile modulus

Yield Strength – 241.325MPa

Higher tensile strength and higher tensile modulus

WEIGHT Weights 25% of steels and 70% of aluminium Due to high weight often requires lifting apparatus where it would not be require for FRP, lowering costs 33% of the weight of steel
ELECTRICAL CONDUCTIVITY Non conductive Requires grounding due to high conductivity Requires grounding due to high conductivity
THERMAL CONDUCTIVITY Good insulator with low thermal conductivity

0.04W/mK

Low thermal coefficient of expansion

12.6 – 14.4 m/m/C *10^-6

Thermal conductivity

50.2 W/m

Low thermal coefficient of expansion

13.5 – 14.4 m/m/C *10^-6 K

thermal conductivity

25W/mK

Low thermal coefficient of expansion

23.4 m/m/C *10^-6 K

IMPACT RESISTANCE Will not permanently deform under impact Can permanently deform

 

Can permanently Deform
COST Lower installation costs, less maintenance, longer product life cause lower lifespan cost – contact us at Protector for more information Lower initial material costs Part Price comparable to FRP
MANUFACTURE AND FABRICATION Can be easily manufactured, easy of complex shapes, can be fabricated with simple carpenters tools. No torches or torches required Often requires welding and cutting tools, with heavy equipment requiring special processes. Good machinability