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Steel is one of the most popular construction materials available. It’s non-flammable and a better choice in areas that might be prone to earthquakes or other natural disasters as it is less likely to warp. It is also stable enough to sustain high winds, which makes it a great option for areas that are often affected by hurricanes.

In fact, it is one of the most durable construction materials available. But its strength and long life span isn’t the only important thing about steel. Its sustainable features make recycled steel one of the best materials available for construction projects.

How it Works

One of steel’s best features is that it can be recycled. In fact, over 90% of a steel building or fixture can be recycled and reused for another project. This is a far higher recycling rate than other common building materials, like concrete or wood. As a result, the steel industry has reduced greenhouse gas emissions by an estimated 36% in the past 30 years.

Recycling steel is fairly easy. The steel is magnetically separated from other materials and then shipped to steel mills or other factors for recycling. It is then melted down and recreated into the manufacturer’s desired molds. In 2019, recycled steel accounted for about 600 million tons of all steel produced.

The primary issue when recycling steel is identifying and separating different steel grades from one another during demolition. According to the Institute of Scrap Recycling Industries, there are 316 different grades of steel.

Why Recycled Steel

The majority of construction demolition are heavy bulk wastes like concrete which are generally downcycled into general fill. However, many companies are seeing the benefits of using sustainable materials like steel instead of or in pair with concrete.

Nowadays, ninety-three percent of all steel used in construction projects is recycled. Why? Because it poses many benefits for companies as well as the environment including reducing waste by diverting it from landfills and back into other projects.

  • It reduces waste and is eco-friendly. One major benefit of reusing steel from buildings and structures is that beams, columns, and other structural pieces can be used without having to be re-melted or processed. Scrap pieces of steel, on the other hand, can be melted down and made into something new. In fact, 98 percent of a building’s steel is recycled back into other steel projects after the building’s life-cycle ends.
  • It retains its quality. Steel’s quality is not compromised, even after it’s recycled. Reusing steel doesn’t degrade the products’ strength or value and it has a great weight capacity.
  • It saves money. While recycled steel is no different in quality than new steel, it is however cheaper. Its lightweight nature means less use of heavyweight equipment and lifts. Additionally, builders save money on maintenance and repair due to steel’s long life span and durability.

When construction projects have the chance to cost millions of dollars, saving on one of your primary building materials is a huge win. Plus, it conserves primary resources and raw materials by using recycled components.

U.S. Bridge & Recycled Steel

U.S. Bridge prides itself on building structures that last. Construction plays a major impact on a country’s environment including its carbon footprint. Steel is a great material to consider in any project.

We’re confident our durable steel bridges will withstand the pressure and be around for decades. To discover what our professional team can do for your next project, please contact us. Or use our new interactive tool the Bridge Scope to determine your project’s scope today.

Galvanizing Steel

Galvanizing steel is the process of submerging steel in a bath of molten zinc which creates a protective layer that prevents future corrosion. Rust is potentially dangerous and can cause metal parts to become stiff and weaken the integrity of the metal and thus the structure.

Repairing deteriorated steel bridges after decades of use is time-consuming, expensive, and difficult to keep up with.

Hot-dip galvanization for steel not only protects metals from corrosion but also improves maintenance-free longevity. Thus, in the long run, businesses are saving money by keeping their steel galvanized and protected. In addition, the galvanization process is environmentally-friendly and resistant to conditions.

Galvanizing Steel: Three Main Steps

Step 1: Surface Preparation

The first and most crucial step is preparing the surface of the material for the coating process. Zinc will not react to unclean metal, so a successful surface prep is a must. Preparing the steel begins by removing all the dirt, grease, and other contaminants from the metal surface. This method is completed by degreasing the metal in a hot alkali solution or other acidic baths.

Pickling

Then the steel material is pickled through a diluted acidic solution for the removal of mill scales and any rust buildup. Depending on the company, this process is either replaced with or accompanied by abrasive cleanings, such as air blasting sand or metallic shot.

Fluxing

The final process for surface prep is fluxing. This procedure eliminates oxides while simultaneously creating a protective coating for the prevention of the formation of any additional oxides.

Step 2: Galvanizing Steel

After the surface of the metal has been prepped, it’s submerged in a large bath of 98% pure molten zinc at 830° F. The zinc reacts to the clean metal and generates a protective layer.

When the steel has reached the same temperature as the zinc bath, it is then withdrawn, drained, and cooled off before moving to the final step. Depending on the size and thickness of the material, this process could take up to 10 minutes or less.

Post-Treatment

It’s possible that a post-treatment coating will be applied to the metal. This process is called quenching. The steel is dipped in mostly water and some chemicals to create a protective layer. Frequently, finishing steps will include grinding off zinc drips for a smooth finish.

Step 3: Inspection

During the inspection phase, the coating thickness, weight, and appearance is meticulously analyzed and compared against the ASTM Standards. There are two different procedures that can be performed to measure the coating’s level of thickness: magnetic gauges or optical microscopy. Magnetic thickness gauge is the most simple and non-destructive thus making it the most popular method.

Analyzing Coating Weight

The second element that is analyzed is the material’s coating weight. The coating weight refers to the volume of zinc coating on the metal surface. Like the coating thickness inspection process, coating weight has two different methods for measuring the weight. Both the weigh-galvanize-weigh and the weigh-strip-weigh procedure should only be applied to single specimen inspection. These methods have their pros and cons so it’s important to choose the procedure that works best for you.

Final Galvanizing Steel Step

The last component that is inspected is the steel’s appearance and coating finish. All sections of the material are inspected to ensure that it meets the proper standards. As mentioned before, zinc will not react to unclean metal. Thus, the steel’s appearance and finish provides useful information such as revealing any errors that occurred during the galvanization process.

U.S. Bridge is a Certified Steel Fabricator

U.S. Bridge has been serving communities for more than 80 years, building steel bridges that withstand time. We’re a steel fabricator by the AISC for Certified Bridge Fabrication — Advanced (Major) and continue to be a leader in the American steel industry.

Still unsure if galvanizing steel is the right step for your bridge construction? Check our other blogs on the galvanization process and construction services for more information. Contact us today and let’s talk about how we can make your bridge project a long-lasting success.