Concrete is a key building material in most cities, bridges, and other infrastructure. It is reasonably priced, long-lasting, and simple to work with. However, the production of its main ingredient, cement, contributes significantly to climate change.
The need for governments and corporations alike to recognise the need to create a more sustainable environment through sustainable practices and materials is now a global imperative. The construction industry is crucial in this regard. It is critical that people take advantage of every opportunity to reduce the environmental impact of materials and construction.
Nevertheless, the industry has taken several promising initiatives in the last decade to improve its sustainability in order to achieve net-zero emissions by 2050. These initiatives range from the use of alternative materials such as waste materials to the optimisation of concrete production processes and the use of alternative energy sources.
To address this, New Zealand’s leading concrete specialist and manufacturer is set to bring concrete made using concrete technology to the country in July 2021. The technology in concrete that could save New Zealand the number of carbon emissions equivalent to 6.3 flights Auckland to Christchurch for every house built here on average has been brought into the country by a leading manufacturer.
Its arrival in New Zealand has been dubbed an ‘absolute game-changer,’ because cement is responsible for 8% of global CO2 emissions, a greenhouse gas implicated in climate change. Concrete has surpassed aviation fuel as a global climate culprit: prior to Covid-19, aviation fuel accounted for 2.5% of CO2 emissions.
“A key component of concrete is cement,” says the General Manager of the company. He mentioned that cement has a very high CO2 impact because it is made from the burning of limestone. This new, high tech concrete reduces the amount of cement used by injecting CO2 gas into the manufacturing process, effectively sequestering it, and replacing the lost volume of cement with the same volume of gas.
“Even better, the CO2 is captured from emissions produced in the refining of petroleum – such as from Marsden Point. Captured this way, it put into pressurised tanks, and shipped to us, then added to the raw materials during the batching process, before it’s mixed in and put in trucks to a destination. It thus has a dual CO2-reducing action” he then added.
When CO2 is injected into the concrete mix, it reacts with the calcium ions in the cement to form a nano-sized mineral called Calcium Carbonate, which becomes embedded in the concrete. This strengthens the concrete, allowing for mix optimisation while also removing CO2.
In just one visit, the carbon concrete device equipment is retrofitted into concrete plants. The device valve box is linked to the onsite CO2 tank and injects a precise dosage of CO2 into the concrete during mixing. The concrete control box communicates with the batching software at the plant, making adding CO2 to a mix as simple as flipping a switch.
A telemetry system is also used to collect data from each control box, which is synced in real-time with the carbon concrete device command centre, allowing device staff to maintain the technology’s 99% uptime and administer ongoing support remotely with quick response times.
The New Zealand concrete industry is halfway towards meeting its target of a 30% reduction in carbon dioxide emissions by 2030, says the latest press release by the industry association. In contrast, switching entirely to sustainable cement could save between 1.72 and 2.75 billion tonnes of CO2 emissions per year, depending on the technology used. To accomplish this, people must revolutionise the way cities are built, shifting to sustainable cement technologies that reuse industrial waste and drive a circular economy.
