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Structural steel and concrete are the two most common materials used in the building and construction industry. Regardless of the type of structure you are building, steel and concrete are among the options you should consider. However, the big question is which of the two is stronger, and which one should you choose for your building project?
Generally, steel is designed to withstand fires and hurricanes and last longer than concrete. In this article, we'll go deeper into the differences between the two materials to help you understand which is better and allow you to choose the best according to your preference.
Structural Steel VS. Concrete: Which is Stronger?
Compressive and tensile strength
Strength under this context describes two things which are tensile strength and compressive strength. The two are pretty different, with compressive strength describing the amount of pressure a material can bear. In contrast, tensile strength describes the opposite, which is how the material can withstand pulling.
Steel
Most modern buildings today are made from mild steel, a low-carbon steel recognised for its flexibility and ability to be carburised when subjected to high heat conditions. The critical thing to remember is that steel is generally a more resilient building material in terms of strength alone. Its tensile strength is about 58,000 PSI (pounds per square inch), while its compressive strength is around 36,000 PSI.
Concrete
On the other hand, concrete is not as strong as structural steel. The tensile strength of concrete is 725 PSI, while the compressive strength of concrete is 4,000 PSI. This is a lot lower when compared to steel—the low tensile strength of concrete results from mixing cement, aggregate stones, and water.
Weight Vs. strength
Another distinguishing feature to recognise is the strength-to-weight ratio, also known as specific strength, which generally shows the strength of the material with respect to its density. This is another area that distinguishes the two materials from each other.
Steel
The steel weight is around 490 pounds per cubic foot (7849.8 kilograms per cubic metre), and because it has high compressive strength and tensile strength, its strength-to-weight ratio is equally high, around 46.4Nm/kg. This is much higher than concrete, and it's worth noting that steel is equally more resilient than concrete.
Concrete
On the other hand, concrete is a lot lighter than steel, and it weighs around 150 pounds per cubic foot (2403 kilograms per cubic metre). In addition, its specific strength is around 5.22Nm/kg. With that, steel is the better option as it is lightweight and equally stronger than concrete.
Fire resistance
The next distinguishing feature of the two falls into the arena of fire resistance. Nobody plans for flames to consume their property. Still, when this happens, the material you use for the construction is a primary determining factor of the level of damage that will occur.
Steel
Structural steel is a non-combustible and fire-resistant construction material. Unlike timber, it doesn't ignite and only gets engulfed by fire in rare cases. The only case where steel has the potential to soften is if the temperature approaches 600 degrees Fahrenheit (314 degrees Celsius). Basically, the steel wouldn't burn, but it could melt, flex, or bend under extremely high-temperature conditions.
Concrete
On the other hand, concrete is equally naturally non-combustible and fire-resistant. This makes it a similarly smart option to consider regarding fire prevention. Interior concrete on buildings helps to create a fire-resistant shell that can effectively resist flames from spreading throughout the house. Regardless of the temperature condition, the concrete doesn't burn, unlike steel, which melts under high-temperature conditions.
In hot and cold climates
Construction materials don't fare equally under all climatic conditions. Some are generally more versatile than others, and knowing their differences is essential. The big question is how climate impacts structural steel and concrete.
Steel
The main concern about structural steel is the potential to expand when subjected to high-temperature conditions and shrink under cold-temperature conditions. Different elements like fasteners and more connect steel structures, and during temperature changes, these fasteners could potentially pull apart and alter the structural integrity of the building.
Concrete
Unlike steel, concrete is less tolerant of temperature changes. Rapid temperature changes can cause dips that could trigger thermal shock, spalling, and cracking of the external layers of the building.
Corrosion and water
Another important distinguishing feature is water exposure because it affects the two materials differently. This basically relates to how well the building will hold water, and here's how they differ from each other.
Steel
Steel buildings are more likely to build rust over time and with prolonged exposure to acidic rain, moisture, and airborne chemicals. Corroded steel can cause leakages and other factors that could put your structure at risk. The good thing is that there are ways to prevent this event.
Concrete
Steel rusts primarily because it's an alloy, but you should note that concrete also corrodes. There are natural acids in saltwater and rainwater, which can potentially erode the outer layer structure. Additionally, one of the significant concerns regarding reinforced concrete is the steel bars embedded within the structure.
Longevity
The next thing to look at is how long the two materials can last. This is a critical factor that can influence your decision, especially when choosing between the two materials.
Steel
The general prediction for steel structures is that they can last up to 50 to 100 years. However, it's still uncertain how long they can last, considering there have been many technological advancements recently. However, you should remember that steel is generally designed to last for many years while effectively maintaining the structural integrity of the building.
Concrete
Concrete is also expected to last 50 to 100 years, like steel. However, when it comes to waterproofing, it's expected to last longer due to reduced exposure to salt and acid.
Other Factors to Note
In addition to everything above, there are many other factors that you should have in mind, and they include the following:
Versatility
When it comes to the level of versatility offered by both materials, it's important to note that the two materials also differ from each other. Steel provides more flexibility, and when it is pre-engineered, it can exceed your needs. Customising it is also easy, and you can make customisations to its shape, insulation type, height, and width.
On the other hand, concrete is also a versatile option, especially in terms of purpose. For example, moulding makes it possible for hardened concrete to be applied for use as a tilt-up roof, sidewalk, roof, floor slab, and more.
Cost
Another thing that probably comes to mind is which of the two options is more cost-effective. Steel is more affordable because it does not require much labour and material. The better the corrosion resistance and strength of the steel, the more expensive the material is likely to be.
On the other hand, concrete construction mostly comes with a heavier price tag. Besides being more expensive, concrete buildings generally take longer to construct, which involves using expensive machinery.
Sustainability
In terms of sustainability, the two materials are also different. Steel is a 100% recyclable material. It can be easily melted and used in producing other materials again. It's the greenest material on earth today.
On the other hand, concrete is not a material that can be recycled. Reports show that concrete creates up to 8% of the CO2 emissions produced in the world today, mainly during cement production.
Steel Stays Winning
Discussed in this article are the main differences between the two building materials, and from everything above, the stronger option entirely depends on the construction it will be used. In general, steel is a better option, but if you're not convinced, you can speak to a professional steel fabricator to get more details on how steel is stronger than concrete.
