What Materials Could Make Underground Construction More Durable in the Future?

By Ellie Gabel

As cities expand and IT infrastructure grows, demand for underground construction is rising. While that’s largely good news for firms in this space, it also means ensuring subterranean structures are as durable as possible will become all the more crucial. Capitalizing on novel materials may be an integral part of that shift.

Conventional concrete and steel are affordable but can pose longevity concerns. However, several alternatives have emerged over the past few years that could deliver additional strength and resilience.

Bentonite

Some of the most elegant solutions come from nature. For instance, bentonite clay deserves consideration for its use in leak prevention in underground walls, where groundwater and pressure raise flooding and corrosion risks.

Bentonite swells to several times its original size when wet. As a result, it’s an ideal medium to protect subterranean infrastructure. Any water that passes through will cause the clay to expand and plug gaps before moisture can seep too dramatically and lead to extensive problems. Corrosion-resistant metals are still necessary, but bentonite can prevent the worst outcomes.

Hydrophobic Backfill

New research has found that a combination of polydimethylsiloxane and a silane-based coupling agent could offer similar benefits. The mixture resulted in a hydrophobic backfill to replace cement when filling unneeded gaps left by tunneling processes. Because the material is hydrophobic, it effectively eliminates moisture buildup.

More promisingly, the PDMS comes mostly from mining waste. Using it also minimizes the demand for cement, which significantly reduced backfill costs in one study, highlighting the material’s potential for large-scale use.

Polymerized Sulfur Concrete

Using concrete made from polymerized sulfur instead of conventional cement is similarly promising. These novel mixtures showcase impressive compressive strength while exhibiting better moisture resistance than traditional alternatives. As a result, they’re ideal for underground construction, especially in coastal areas.

In current applications, metals need a pitting resistance equivalent number of 32 or greater for use in projects where seawater corrosion is a threat. This limitation severely restricts what firms can use and may raise costs. However, using inherently moisture-resistant concrete would reduce the need for high-resistance metal reinforcements, resulting in lower costs despite higher strength.

Carbon Fiber-Reinforced Concrete

Alternatively, subterranean infrastructure can use concrete reinforced with carbon fiber instead of rebar. Carbon fiber is as light as magnesium but twice as strong, resulting in lighter concrete to reduce sinking risks in projects dealing with soft or moist soil.

Using carbon fiber instead of steel rebar also minimizes corrosion concerns, as carbon fiber is far less susceptible to moisture and rust. While this approach entails higher upfront costs, the resulting long-term benefits may make up for it over time.

Nanomaterials

A newer but still promising solution is to strengthen concrete and other materials with nanoparticles. Many substances exhibit unique properties on the nano-scale, and capitalizing on that potential can lead to impressive durability improvements.

Some nanoparticles create anticorrosive coatings for metals, letting underground projects address moisture concerns without a dramatic redesign. Many nanomaterials have antimicrobial properties, too, which can lead to cleaner or less environmentally damaging underground infrastructure.

New Materials Open Promising Opportunities

While many of these resources require additional research and development before they’re ready for commercial use, they showcase a positive trend in underground construction. Newer alternatives to conventional materials can increase durability and reduce corrosion concerns to enable safer expansion. Learning about these possibilities now is the first step to building a more cost-effective future.

Ellie Gabel is a freelance writer who specializes in covering the latest innovations in science and technology for an audience of industrial professionals. She is also the associate editor at Revolutionized.com.