Green concrete lowers construction emissions
Concrete is everywhere, and it leaves a serious carbon footprint. The production of this material is the third-highest source of CO2 in the world, and it is expected to continue expanding in the upcoming years.
Concrete is cheaply available and widely distributed. Therefore, the financial incentive to maximize efficiency in its production is low. Environmental damage is rarely factored into market costs, making it difficult to effect change in the industry.
Scientists and developers alike are looking for a more sustainable solution. Here’s the environmental impact of concrete construction and an overview of the innovations that may change how we mix, use, and recycle concrete.
The principle of using concrete for building construction has been around for thousands of years. The product we identify as cement today was invented in the 1820s in England and is commonly referred to as Portland cement, named for its comparability to a building stone from the Isle of Portland.
Concrete is made from mixing water with cement and other aggregates. Cement is composed mostly of limestone. About 60-80% of concrete is aggregate materials, rock, stone, sand, or a combination of those. Some forms of decorative concrete, such as fiber cement, can be produced by combing cement with cellulose or synthetic fibers.
By volume, water is the only substance humans use more than concrete. Today, innovators are working on a more sustainable concrete and improving the life cycle of what’s already been produced.
In 2012, the global production of concrete was more than 4.1 billion tons. After a look at these statistics, the future of sustainable concrete may seem dubious. However, companies all over the world are looking for better solutions. Because concrete has such a negative ecological impact, both in how it’s produced and how it’s utilized, the momentum behind possible alternatives is growing steadily.
The primary issue of developing more sustainable concrete stems from the core problem of its makeup. Concrete is composed of raw materials that require fossil fuels to extract and process. Additionally, recycling used concrete can be complicated and time-intensive.
Alternative materials are not readily available, and there are still improvements to be made in creating green concrete. There are currently two methods of reducing the impact of concrete:
- Extending the life cycle of concrete by recycling it.
- Changing the formula of concrete to include more sustainable aggregates and alternatives to conventional cement.
Innovations in Green Concrete
Innovators all around the world have been looking for ways to improve concrete production. There is potential to change not only how it’s produced, but also how it is manufactured, installed, and disposed of.
Companies such as Gammon, Metromix, and the QUIKRETE Companies are looking to improve the process of manufacturing. Production plants are more readily engaging in Life Cycle Assessment tests, a method that studies the impact of a product on the environment. In addition, the EU established a goal to recycle 70% of construction waste by 2020, including concrete.
The two main innovations in developing more sustainable concrete deal with the beginning and end of its life cycle. The first is creating a better mixture that requires less energy to produce. The second is reusing concrete after it has been assembled, instead of tossing it in a landfill.
A Better Mixture
Research has been conducted on looking to alternative sources for aggregates in concrete. Some of the most popular substitutes include graphene, fly ash, and ground granulated blast furnace slag. While these materials extend the life cycle of by-products of the fossil fuel industry, their overall sustainability is low, especially as conventional energy systems move toward renewable options.
More imaginative options range from adding aluminum can fibers, mixing carbon dioxide released from power plants with seawater, and using alternative reinforcements such as recycled plastic.
Australia’s Fibercon created a green concrete that uses blast furnace slag instead of Portland cement. While it’s priced the same as the traditional source, the impact of this alternative is significantly more positive. Producers saw a 90% decrease in carbon emissions by replacing Portland cement with blast furnace slag.
There is vast potential to recycle concrete, and new technology is making the process easier. The action of disassembling concrete can be time and energy-intensive.
One particularly interesting solution was discovered by the Fraunhofer Institute in Germany. Scientists found that striking concrete with short bursts of lightning separated the parts. These parts can then be reincorporated into cement materials to create recycled concrete.
Other types of concrete, such as fiber-cement and concrete masonry units (CMU), can be more readily recycled. In fact, some CMU options can be developed with 30% recycled material and earn LEED points for new construction. As technology continues to expand the options for recycling concrete, researchers hope the life cycle of concrete can be extended and less will end up in landfills.
Building a Future With Sustainable Concrete
Finding alternatives to contemporary concrete production is a must for sustainable construction. Innovators have found success in a variety of methodologies, and there is a global effort to rethink not only how concrete is produced, but also how it is utilized.
Considering the colossal impact of concrete, finding a better way to create and manufacture this material is essential to building a greener future.
Holly Welles is a real estate writer who covers the latest market trends in everything from residential to commercial spaces. She is the editor behind her own blog, The Estate Update, and curates more advice on Twitter.