The global human population reached 8.0 billion in November 2022. According to the U.N., it is expected to further expand 0.7% annually to 9.7 billion in 2050. Keeping pace with the population growth is the global GDP growth expected to grow 2.2% annually through 2050. These key drivers will result in significant growth in construction industry. Carbon dioxide (CO2) emissions from producing building materials including concrete, steel, aluminum, glass, and bricks reached 3.6 gigatons in 2021, representing 37% of the global emissions. Although some progress has been made on the policy level and with an increase in investments, there must be greater effort to reduce emissions.
There is massive emissions reduction potential from material efficiency applied across the construction industry. Improved material efficiency and use of recycled materials can drive greenhouse gas emissions reductions by over 50% in 2050 compared to 2021. ADI and ADI Chemical Market Resources’ recent work has looked at several materials and options that could decarbonize the construction industry. Coal-based or mechanically recycled waste plastic bricks can be used to replace traditional fire clay bricks. Additionally, materials like low-carbon cement produced from sequestered carbon or cement with lower Portland clinker content will also aide in lowering CO2 emissions from the construction industry.
Talking about coal bricks, Penn State University is working on developing coal bricks that have the same manufacturing process as traditional fire clay bricks, but do not require energy intensive curing. They have improved performance as well as cut costs. They are up to 3X stronger than clay bricks with improved durability. Reduced porosity and permeability make them moisture and weather resistant but they are still 70% lighter than regular brick reducing transportation cost and energy intensity. Moreover, since they do not require kiln drying or clay mining and can be recycled to be used as agricultural supplements, they are much more sustainable than traditional clay bricks.
A second source of alternative feedstocks for construction materials is waste plastic. Several efforts are being made to utilize waste plastic and mechanically recycling it into bricks from companies such as Scotland-based Recycle Build with Precious Plastics who claim to recycle at least 1.5 kg of plastic per brick or Kenya-based Gjenge Makers who makes bricks from crushed mixed household plastic waste that are lighter but 5X to 7X stronger than concrete. Utilizing mixed plastic waste for bricks not only eliminates need for energy-intensive traditional fire clay bricks and cement but also provides long-lasting waterproofing and weather resistance that typically require additional treatments.
Finally, low-carbon cement will also help in reducing CO2 emissions from the construction industry. Cement production leads to 600 kg of CO2 emitted per ton of product. Portland clinker is an intermediate product that makes up about 90% of Portland cement. However, it has recently become technically and economically viable to lower the Portland clinker content in cement to as low as 50% and replace it with limestone calcined clay cement making a final product that is 40% less carbon-intensive than Portland cement. Canada-based CarbonCure Technologies creates carbon removal technologies to inject the CO2 into fresh concrete, after which the CO2 undergoes mineralization and becomes permanently embedded in the concrete, reducing its carbon footprint without compromising performance.
ADI is actively following energy transition and decarbonization efforts in the hard-to abate sectors and helps clients including technology developers, adopters, and investors navigate the highly dynamic market. Contact us to learn more.
By Panuswee Dwivedi, Dustin Stolz, and Manuel Diaz
