In the third century BCE, the Romans made the first concrete mixture by combining water, volcanic ash, gravel, and gypsum or lime. Two centuries later, concrete has earned its place as a dependable architectural building material.
Steel’s investigation as a building material, on the other hand, is not nearly as ancient; because of the complexity of its manufacturing process, it was not commonly utilised in building and construction until the mid-19th century. In the 1850s, new techniques sped up the production of steel, and it swiftly rose to prominence as a solid and sturdy building material. Over the next 150 years, steel’s popularity continued to grow, and now, along with concrete, it is one of the most widely used building materials.
Which of these materials is therefore better appropriate for your project?
There are a number of factors to consider if you are deciding whether to use concrete or steel as the primary construction material for your project. Both are equally worthy building materials. Concrete is considerably more expensive, but presumably gives superior overall performance. To determine which product is best for your project, you must compare their strength, durability, fire resistance, sustainability, and, of course, cost.
1. Strength
Compressive strength is the capacity of a material to withstand a crushing force. In a building, the compressive strength of the slabs, beams, columns, and structure enables these parts to withstand the vertical loads without suffering damage.
Tensile strength is a material’s resistance to breaking when stretched. The ability of a light beam to withstand vertical loads is an example of its tensile strength, since it prevents its base from elongating and cracking when loads are applied to its top.
Shear failure is caused by two unaligned pressures acting in opposite directions on a building, and typically occurs after an earthquake or as a result of strong winds. The capacity of a product to resist this type of failure is its shear tenacity.
The compressive strength of concrete is excellent, yet it is somewhat fragile and splits easily under tension. To counteract this weakness, tension-resistant reinforcing bars are implanted directly into the structure. These bars are typically made of steel, but composite options are also available.
The general toughness of reinforced concrete derives from the concrete’s compressive strength and the tensile strength of steel rebars. The shear strength is provided by the stirrups, which are considerably shorter, perpendicular bars linked to the vertical members of the structural member.
Steel’s tensile strength is one of its most sought-after characteristics, but expertly fabricated steel structures have the same overall strength as their reinforced concrete counterparts. In order to achieve enough compressive, tensile, and shear strength in a steel framework, sound structural design is essential.
2. Lifespan
The degree to which a material can withstand its conditions is its longevity. Both reinforced concrete and steel can endure for a very long time without deteriorating if their configurations are optimised.
When properly adjusted, reinforced concrete can withstand cycles of freezing and thawing, chemicals, salt water, moisture, sun radiation, and abrasion. Because it is not a natural substance, concrete is not susceptible to vermin attacks. Significantly more importantly, it does not burn or melt.
However, despite its excellent durability, reinforced concrete conceals a significant issue: its corrosion-prone steel reinforcement. Rusting rebar loses its link with the surrounding concrete and forms iron oxide, which causes tensile strains and ultimately disintegration by expanding. Although concrete’s natural alkalinity reduces rebar corrosion, reinforced concrete exposed to seawater or large amounts of deicing salt may require further protection. For this purpose, epoxy-coated, stainless steel, or composite rebar performs admirably.
Structural steel is equally susceptible to rust as rebar and requires additional protection. Paint, powder finishing, sacrificial coatings, and deterioration-inhibiting chemicals are all methods for eliminating or limiting corrosive steel damage.
3. Fire Resistance
The structure of reinforced concrete renders it largely inert and consequently fireproof, while its low rate of heat transfer prevents fire from spreading between spaces.
However, both the concrete and the steel support can lose their tensile strength when exposed to high temperatures for an extended period of time. Depending on the aggregate type, concrete may begin to lose its compressive strength between 800 and 1,200 degrees Fahrenheit. As a result of its shielding capabilities and reduced rate of heat transfer, lightweight concrete offers the best fire resistance, according to scientific research.
The fire resistance of architectural steel is inferior to that of reinforced concrete. It begins to lose strength at temperatures over 550 degrees Fahrenheit and retains only 50 percent of its space temperature yield strength at 1,100 degrees Fahrenheit. A variety of techniques can reduce the cost of temperature rise in the structural steel components of a building. These may incorporate fire-resistant coatings, barriers, cooling systems, concrete covering, as well as active systems like sprinklers.
4. Sustainability
Both concrete and steel provide environmental benefits when used in construction. Approximately 85 percent of all steel used on the earth is eventually recycled. It makes perfect sense, given the amount of scrap steel and the simplicity of the recycling process. In addition to reducing the demand for newly mined resources, steel recycling consumes just a third of the energy required for steel manufacturing.
Additionally, concrete possesses a number of enduring properties. The majority of it comes from family members in close proximity to the building and construction site, reducing the amount of energy necessary for delivery. After demolition, the debris can be repurposed into gravel, aggregate, or paving materials for road building, disintegration control, landscaping, and coral reef restoration, among other applications. Concrete that has not been tainted may be used as a component of new mixtures.
Recycling concrete provides numerous environmental benefits. It keeps rubbish out of landfills, reduces construction waste, and replaces crushed rock and accumulations that would otherwise be mined and transported.
5. Expense
Typically, enhanced concrete is a more expensive option to architectural steel. The labour and materials related with installing formwork and rebar, pouring concrete, and ensuring that it cures properly can represent a sizable portion of the total cost.
Accordingly, concrete prices are very stable. Since the year 2000, prices for a variety of concrete goods have increased steadily with the cost of rising cost of living; this is a crucial aspect to consider when estimating future employment.
Despite the higher cost, insurance experts recognise concrete’s strength, durability, and fire resistance. Typically, insurers supply concrete structures with higher safety ratings and lower premiums.
Steel is less expensive and quicker to instal than concrete, but has a longer lead time. Due to its lower fire resistance, steel frames typically have higher insurance costs.
