How the Building Industry Can Move On From Concrete

There are a lot of great reasons to use concrete. It’s strong, long-lasting and cheap to use in construction.

However, its production is also responsible for a sizable chunk of the world’s carbon emissions. And concrete’s impact on the environment has many industry professionals, environmental agencies, and governments wondering about the real cost of its use.

In light of these concerns, the industry is looking for other materials that can offer the same benefits as concrete without the downsides, or just less environmentally-impactful ways to produce it. This guide will highlight some of those options.

Concrete and the Environment

Concrete has been used to build structures, roads, dams, and more for centuries, but it’s in more demand now than ever.

Estimates show the production of concrete is responsible for up to eight percent of the total emissions produced — mainly carbon dioxide, a greenhouse gas. This is among all industries and countries, meaning it’s a significant factor in environmental pollution.

Also, it’s worth considering just how much concrete is already a part of the landscape. Some estimates believe concrete already outweighs the combined biomass of trees, bushes and shrubs on Earth. As we build new structures while the old ones degrade, the mass only grows.

How concrete is produced

Concrete is made by combining sand, gravel and cement. Emission concerns derive from the cement production process.

Cement requires heating limestone and clay to extreme temperatures in a kiln, separating the calcium oxide and carbon dioxide in the limestone. The calcium oxide forms with the cement, while the carbon dioxide is released into the environment, intensifying the greenhouse effect.

Is it renewable?

Concrete is not renewable. However, in some ways, there are second uses for it.

The concrete from demolished buildings and structures can be ground into fill for use as road pack or base, landscaping, drainage and gravel. However, the process of crushing this material into a useful size is also fossil fuel-intensive. It requires heavy machines to demolish buildings, collect the debris, then grind it into smaller, usable pieces.

While not renewable, many proponents of concrete do see it as sustainable. This is likely due to the large supply of required materials, the long lifespan of a concrete structure, its thermal mass, and its ability to reabsorb carbon dioxide once the structure is built. And with advancements in modern concrete technology, self-healing concrete is nearing commercial use.

Top Concrete Alternatives in Building

With many looking to limit or cease cement production, there’s a call for concrete alternatives in building. The following materials could potentially claim a share of the market as technology, research and awareness increase.

Ferrock

This is made from steel dust and silica, the byproducts of steel and glass production. Ferrock is stronger and more flexible than concrete. It also binds carbon dioxide from the atmosphere, reusing some potentially harmful greenhouse gasses. This could make it a carbon-negative alternative to concrete.

Rammed earth

This is the process of packing damp soil into a form (similar to a concrete form) under a lot of pressure. Once it cures, the product is strong and sturdy and serves as an impressive thermal mass.

It’s labor intensive, however. The finished product features layers of material that offer visual appeal and many of the same benefits as concrete.

Timbercrete

This still contains cement, just at lower volumes than concrete. It’s made by mixing sawdust (a byproduct of lumber production) and cement. It’s lighter than concrete while nearly as strong and weather-resistant.

Hempcrete

This is made from hemp shives, the byproduct of hemp fiber production. When mixed with lime, sand and pozzolans, it forms a concrete-like material that rivals concrete’s compressive strength and durability. It also absorbs carbon dioxide, making it a potentially carbon-negative alternative to concrete.

Greencrete

Greencrete is essentially a catch-all category of blocks and cementitious materials made from recyclable materials. These may include plastic, polystyrene and other materials that would otherwise sit in a landfill.

Alternative concrete production methods

The construction industry is also looking into more environmentally friendly methods of producing concrete, like the viability of using electricity instead of fossil fuels to heat the limestone and clay. (Research is ongoing.) Other possible options include trapping the carbon dioxide in the concrete mixture, or capturing and burying it at sea.

Are Concrete Alternatives Viable?

Yes. In many cases, concrete alternatives have already been used to create structures. However, they aren’t readily available or in widespread use yet because concrete is still economical.

But with the push for the use of greener, more renewable building materials in construction, these materials are likely not far off from becoming everyday materials.