Sustainability has and will continue to grow within every industry, especially the construction industry, as we head into a future wrought with uncertainties. Buildings generate up to 35-percent of all greenhouse gases, 35-percent of landfill waste is a direct result of construction and demolition activities and 80-percent of water is consumed in and around buildings, which lends credence to the fact we need to build based on green initiatives to impact the environment positively.
Concrete has been one such product which has been extensively researched to minimise the pollution impact. Concrete is the most used man-made material in the world. In fact, twice as much concrete is used around the world than the total of all other building materials combined. Cement is one of the chief components of concrete that harms the environment a lot. According to ‘The Concrete Conundrum’ published by Chemistry World, cement generates 1.5 billion tons of CO2 per year, which accounts for 5-percent of the total CO2 production in the world. Concrete also uses 1-billion tons of water. Add to that the 9-billion tons of aggregate used for concrete, which has a depletion effect on our natural resources, and we can surmise that concrete properties themselves are not going to save the environment.
Move towards concrete development without cement
Researchers from the Swinburne University of Technology have created a new type of concrete that is made from waste materials. The new concrete can bend under load, making it suitable for construction in earthquake zones. The waste product used in the concrete is fly ash, a by-product of coal-fired power stations. In earthquake zones, the brittle nature of traditional concrete can lead to building collapses. Concrete is the most widely used building material around the world.
Traditional concrete is prone to shatter when stretched or bent and has a huge carbon footprint due to the calcination of limestone to produce cement, the key ingredient in concrete. Using industrial waste products has allowed the team to make the concrete more durable.
Production of their new concrete needs about 36 percent less energy and emits up to 76 percent less carbon dioxide compared to conventional bendable concrete made of cement. The team also included short polymeric fibers in the new concrete to allow it to sustain multiple hairline cracks under tension or bending without breaking into pieces.
According to tests, the new concrete is about 400 times more bendable than normal concrete while retaining similar strength. The team has not indicated when or if the new concrete might be ready for commercial use. The main use envisioned for the material is building in areas vulnerable to earthquakes, hurricanes, projectile impacts, and blasts.