Updated: Aug 7, 2019
The construction and operation of our built environment, including buildings, roads, homes, and factories, is responsible for a remarkable 39% of Carbon Dioxide (CO2) emissions in North America. Due to global interest in combating climate change and lowering our impact, industry professionals are aiming to make buildings operate more efficiently, targeting standards like LEED, PassivHaus, and Green Globes. However, producing the materials we use to build our cities takes a heavy toll - cement manufacturing alone accounts for 8% of global emissions. Here are 2 exciting ways that the industry is going green:
Concrete is the world's most popular building material - malleable in any form and flexing a high compressive strength, its versatility makes it practical for almost any building project. However, concrete has a high environmental footprint; producing cement, the binding material of concrete which makes up about 15% of its mass, is
responsible for 8% of greenhouse gas emissions. Supplementing the cement mix with "cementitious materials" - fly ash and blast furnace slag left over from coal burning and steel manufacting, lowers this figure marginally. However, the real innovation is the cutting edge process of carbon sequestration. Researchers are now using CO2
captured from industrial processes to manufacture synthetic limestone - a key ingredient in any concrete mix. Shifting the demand for limestone mining, and pulling CO2 out of the atmosphere, this magnificent technology can lower concrete's carbon bill by over 50%, keeping it relevant as an ideal building materials in an environmentally-stressed age.
2. ENGINEERED LUMBER / MASS TIMBER
For thousands of years, people have been building our world with wood. However,
deforestation is becoming dangerous to the welfare of our ecosystems, and harvesting old-growth trees for structural applications is no longer viable. Although many see wood as a weak, flammable material, it is safe and reliable when compared to steel or even many concrete mixes. Moreover,
because trees absorb carbon dioxide when they are living, wood has a very low footprint. Recent innovations in wood technology have allowed for large, strong beams to be manufactured from smaller pieces of lumber. CLT (cross laminated timber) and DLT (dowel laminated timber) fasten many smaller pieces of lumber together with heat and compression to create larger, stronger pieces that are useful for multi-story construction. With these innovations, much larger wooden structures are now feasible than even before; for example, the University of British Columbia recently completed it's new Brock Commons Residence, an 18 story high-rise erected primarily with mass timber framing.
Not only are the changes we see in the built environment exciting, they are also increasingly contributing to lowering the world's dependence on fossil fuels and helping us to reach new heights with environmental sustainability.
Stay tuned for more posts on technological innovations in the engineering & construction industry!
Written by Simon Law, Civil Engineering '21.