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✓ Before the 21st century, civil engineering was mainly about building a house or office tower that complies with codes while minimizing costs. That’s no longer the case in this era, argued experts from the University of Michigan’s Global CO2 Initiative. Today, every engineer—new or old—has to learn how their choices of materials and techniques affect the world.
✓ Then again, it’s not like all this is news to many. At one point in Earth’s history, society had to contend that asbestos, a once widely used building material, is a slow-acting killer. Despite its affordability and availability, it fell out of favor in construction, leaving the industry to look for a viable successor. Still, the cost has prevented such materials from seeing prevalent use.
✓ However, civil engineering has to move beyond traditional considerations in modern times. The initial costs should only come next to cost-effectiveness, as in a substitute offering similar properties to the original but requiring fewer resources over its lifetime. Case in point: aluminum as a more sustainable alternative.
More Than ‘Environment-Friendly’
✓ To understand what makes aluminum sustainable, it pays to comprehend the meaning behind the term ‘sustainable.’ Most people define it in an ecological context, but it’s only one of three key elements. It’s also concerned with long-term economic and equitable implications.
✓ In the case of aluminum, its production (at least, the way it’s currently produced) already fails the ecological litmus test. Aluminum doesn’t occur naturally; smelters extract it from bauxite, an energy-intensive process. While efforts to decarbonize aluminum production have been underway for years, the industry largely derives its energy needs from coal.
✓ Recycling aluminum, however, is a different story. The Aluminum Association estimates that at least three-quarters of the metal produced is still in use in some form across various industries. Moreover, it consumes far less energy than production, as recycling involves finished products instead of raw materials. Specifically, it doesn’t include processing fresh bauxite, although some isolation may be required.
✓ The savings generated through recycling aluminum can be reallocated to other uses, particularly powering millions of homes. With this much circulating, demand for new aluminum can be kept to a minimum, scaling down mining and smelting operations.
✓ Even if aluminum is one of the most abundant metals, sustainability always assumes it’s as exhaustible as the resources used to make it. For this, people must consider ways to use what they have wisely. Such a mindset benefits construction projects looking to save on building materials like aluminium windows without compromising quality and safety.
✓ All this leads to perhaps the most crucial facet of sustainability: preserving as much of Earth’s habitableness for the next generations. Fewer new mining sites, if any, would have to be opened to meet aluminum demand, leaving more resources for everyone’s children.
Sustainable Properties
✓ A report by the International Aluminum Institute projects demand for aluminum in construction to be lower than in other sectors for this decade. Despite a gradual shift toward green building codes and practices, it’s anyone’s guess whether they’ll have a noticeable impact. Some regions only promote but don’t mandate aluminum use.
✓ But based on the report’s numbers, construction will still have the second-highest global demand by 2030 at 25.9 metric tons. It falls on policymakers to improve this figure, taking advantage of the recent surge in residential construction. After all, there’s no reason for a single-family house or an apartment not to be as green as a commercial building.
✓ If anything, homeowners can benefit from aluminum’s properties.
a. Impressive strength-to-weight ratio
✓ Regarding material strength, ubiquitous steel will always come out on top. However, its high density will be a significant disadvantage in some construction applications that warrant a balance between strength and weight.
✓ Meanwhile, aluminum’s low density gives it decent strength for its weight. Though not the best choice for foundations and supports, it’s ideal for applications like roofing and gutters. Its lightweight properties help lessen the risk of structural failure.
b. High corrosion resistance
✓ Aluminum can react to various acids and bases, a property that scientists call amphoterism. It produces a passive protective layer called aluminum oxide when exposed to moisture or oxygen. This amphoteric compound can maintain its passivity in conditions with a pH level between 4 and 9 (at 25°C or 77°F); any value past that hastens corrosion.
✓ Under most corrosive conditions, aluminum can maintain the oxide layer by ‘re-rusting’ or regenerating it. Even in aggressive environments, the corrosion process is significantly slowed when alloyed with other corrosion-resistant metals. This prolongs their service life in any application, reducing demand for brand-new aluminum building materials.
c. Preferred for renewable energy systems
✓ With the energy sector leaning closer toward renewable energy, aluminum is in a favorable position to be the primary material for creating the necessary infrastructure. According to a research paper by mechanical engineers at McGill University, aluminum possesses the right qualities for building a sustainable power-to-X system.
✓ The metal is already widely harnessed for constructing solar panels for both residential and commercial use, owing to the properties explained earlier. Experts estimate that the energy sector may account for half of the overall demand for aluminum by 2050. It isn’t the supply, as the production emissions cause concern.
✓ The benefits of aluminum extend not only to new constructions but also to renovations and improvements. Industry experts believe the latter to be more sustainable, producing the emissions building from scratch yields. Since property owners are rethinking how their spaces should be used, employing aluminum is a huge bonus.
Conclusion
✓ Decades ago, the goal of the average engineer was to make a code-compliant structure for the least possible cost. Today, climate change and other trends have deemed such a mindset insufficient, if not obsolete. Expense aside, engineers are urged to consider the impact of their decisions on the planet and future generations.
✓ Choosing aluminum is not the primary solution to society’s environmental dilemma. However, it’s one viable approach that must work in concert with others for the best possible effect. Green buildings today already have some form of aluminum, which will most likely remain that way for the foreseeable future.
