Displaying items by tag: curing
CarbiCrete secures steel slag supply from Lafarge Canada
15 December 2023Canada: Carbon-negative concrete producer CarbiCrete has signed a deal with Holcim subsidiary Lafarge Canada. Under the deal, Lafarge Canada will process steel slag at its St. Constant cement plant in Québec for use as an ingredient in CarbiCrete’s CO2-cured cement-free concrete.
CarbiCrete partner Patio Drummond produces carbon-negative concrete blocks using CarbiCrete’s technology at its Drummondville concrete block plant in Québec. The company is on a drive to double the production of CarbiCrete blocks. It first partnered with CarbiCrete during trial production of its material in 2018.
Lafarge Canada vice-president of cement Andrew Stewart said “We are committed to reducing our environmental footprint and leading the way in sustainable construction. Our partnership with CarbiCrete is a testament to our dedication to offering sustainable solutions and actively participating in the circular economy.”
CarbiCrete CEO Chris Stern said “Collaborating with Lafarge allows us to leverage long-established infrastructure and years of expertise in processing steel-related by-products. This enables us to make an immediate climate impact as we scale the deployment of our technology which reduces embodied carbon in concrete by both avoiding emissions and removing carbon through mineralisation.” Regarding the on-going scale-up of production at Patio Drummond’s Drummondville plant, Stern said “Increased production of our carbon-negative blocks brings us closer to our common goal of decarbonising production of the world’s most consumed man-made substance.”
US: A team from the Massachusetts Institute of Technology (MIT) has developed a new method to sequester CO2 in concrete before curing it. The method is based on the addition of bicarbonate of soda, which reacts with cement to produce a calcium carbonate-calcium silicone hydrate composite. The Journal of Engineering has reported that the method adds the benefits of CO2 mineralisation during production and casting, doubling the mechanical performance of early-stage concrete. It also eliminates the effects of carbonation reactions in cured concrete, which weaken the concrete by lowering its alkalinity, which accelerates the corrosion of rebar. The method has the potential to sequester 15% of CO2 emissions from cement production.
The team said “The pre-curing capacity of concrete to sequester CO2 has been largely underestimated and underutilised. Our new discovery could further be combined with other recent innovations in the development of lower carbon footprint concrete admixtures to provide much greener, and even carbon-negative, construction materials.”