Over a quarter of steel produced annually is used in construction projects due to the material’s malleability, strength, and durability.
However, you may have realized that more builders are using recycled steel for sustainable construction, and you might be wondering about the pros and cons of using recycled steel in your building before going that route.
Recycled steel is a sustainable material that saves between 60 and 74 percent of the energy used to produce virgin steel. Moreover, it helps mitigate the negative environmental impacts of manufacturing new steel.
Steel can be recycled by remelting scrap steel an infinite number of times without losing its strength or adversely impacting any of the physical or chemical properties that make it ideal for construction.
In fact, the American Institute of Steel Construction has published figures stating that the recycling rate for structural steel used in construction is 93% across the globe. This is one of the highest recycling rates for any material.
In this article, I’ll discuss the pros and cons of building with recycled steel. I’ll tackle the main points like quality, testing, and environmental concerns. This way, you’ll be able to make an informed decision. Stay tuned!
Most builders use steel in construction due to its strength and durability.
Lately, recycled steel has become common in construction projects because it’s a more eco-friendly material than virgin steel, with excellent strength and high durability.
Conserving energy preserves natural resources like water, fossil fuels, and coal. It also minimizes greenhouse gas emissions, thereby mitigating global warming.
The production of primary steel is an energy-intensive process.
Manufacturing a ton of steel consumes approximately 6.0 MJ of energy. Therefore, it depletes the natural resources that go into energy production. In doing so, it also emits greenhouse gases that cause global warming.
Fortunately, recycling steel is less energy-intensive than producing primary steel. It saves between 60 and 74% of the energy used to produce new steel.
Saving such a high amount of energy makes recycled steel a worthy addition to the list of sustainable building materials.
Construction work entails transporting materials and lifting them to higher floors. As such, cumbersome materials make the process harder and require heavy machinery to lift them to the desired height.
Luckily, recycled steel (and steel in general) is considerably lighter than other building materials, such as timber and concrete, making it the ideal choice for easier transportation and lifting.
It’s worth noting that steel makes some of the lightest structural components. For instance, steel I-beams are lighter than their concrete and timber-based counterparts.
Moreover, recycled steel is highly flexible. You can use it to make slender columns to maximize the working space.
Structural strength and durability are vital to any construction and are some of the qualities that make steel ideal for building.
It is worth noting that recycled steel retains its tensile strength and durability. It’s just as strong as new steel, making it a reliable material for construction projects.
Moreover, recycling steel at the end of its life causes minimal material loss, so builders can be sure they’re getting the most out of their purchase.
It’s essential to consider the cost of materials before embarking on any construction project. This way, you’ll set aside enough capital to finance the project.
Recycled steel is cost-effective because it’s cheaper than new steel and gives builders more value for their money.
Malleability is an essential feature in construction. You can easily shape a malleable material into different forms and shapes. This is especially crucial in making structural components like beams, trusses, and columns.
Recycled steel is highly malleable because it comprises atom layers that slide over each other to allow bending without breaking.
The high malleability of recycled steel makes molding and shaping into different features easy. Consequently, it helps builders save time on projects while achieving the desired look.
Recycled steel promotes green building by reducing the emission of greenhouse gases.
Virgin steel production is an energy-intensive process, which generates more gases like carbon dioxide, sulfur dioxide, and nitrogen oxide — the leading causes of global warming and air pollution.
Recycling steel doesn’t entail open-pit mining and coal coke production — two major processes contributing to greenhouse gas emissions when producing virgin steel.
Steel is manufactured from iron ore, a component extracted from the earth’s crust through opencast mining.
Opencast (or open-pit) mining is destructive and emits a lot of dust. The dust particles released into the air cause localized air pollution and eventually settle in water bodies and on vegetation, leading to land and water pollution.
Moreover, burning coal to produce coke generates pollutants like nitrogen oxide that leak into the atmosphere, where it can cause asthma and acid rain.
Recycling steel eliminates open-pit mining and coke production, reducing air and water pollution and eliminating the risk of local health impacts.
Environmental degradation is the direct impact of opencast mining. The process clears vegetation around mining sites and removes the valuable topsoil that is essential for life, disrupting wildlife habitats.
Bare land is highly susceptible to soil erosion, leading to soil loss, habitat degradation, and pollution in watercourses that the soil washes into.
Moreover, accessing the earth’s crust to extract iron ore can impact groundwater, causing pollution and lowering the water table, resulting in a shortage of safe drinking water.
Recycling steel eliminates the need for open-pit mining and its related environmental hazards. Consequently, it helps preserve ecosystems while protecting wildlife habitats from destruction.
Recycled steel is made by remelting and re-milling scrap steel. The process is precisely controlled, resulting in steel identical to new steel produced from iron ore.
As such, there really aren’t any disadvantages to using recycled steel for construction compared with new steel.
That said, there can be supply chain issues that cause problems with obtaining recycled steel occasionally. It’s also important not to confuse recycled steel with reused, second-hand or reclaimed steel.
Recycled steel is a secondary resource whose availability depends on the supply of scrap metal and the efforts of scrap dealers to collect it.
Occasionally, the availability of scrap metal can become limited due to issues in the supply chain.
Second-hand, salvaged, or reclaimed steel can be reused without remelting if it is the right size and shape and passes stringent quality control tests.
You must take care if you’re considering reusing structural steel members and other components to ensure they are fit for purpose. Steel reclamation firms have taken different steps to ensure quality.
These steps include quality control assessments and tests to guarantee high-quality second-hand steel that meets the relevant building codes.
The primary quality control assessments and tests for reusing steel include:
- Metallurgical testing: It involves evaluating the properties of steel by subjecting it to thermal, mechanical, and chemical actions. This helps understand the material’s structure and its performance in different conditions.
- Jominy test: It tests the steel’s hardenability due to quenching.
- Hardness value test: It measures the reused steel’s hardness value using the Rockwell C scale. The test results help determine if the recycled steel is suitable for construction.
- Tension test: It determines steel’s tension, ductility, and yield strength. Tension tests determine the material’s ability to withstand external forces without breaking.
- Fatigue test: It determines the material’s performance when subjected to fluctuating loads. Based on the fatigue limits, a decision is made on the suitability of reclaimed steel for construction.
Final Thoughts On The Pros and Cons Of Using Recycled Steel in Construction
With these pros and cons of using recycled steel in your building, you’re on the right path to making the best decision.
You should only build with this material if its pros outweigh the cons for your project.
A rule of thumb is to consult a structural engineer and local building authority before using new or recycled steel (and especially before using second-hand, salvaged steel) in your project.
They’ll advise you on the best recycled steel or the best reclaimed steel based on reliable quality control tests.