b'Headline St oryBacteria-based concrete offers climate benefitsHvard EggeTen cubic kilometers ofapproach, it mayhave a massive influence on reducing concrete, equivalent to the the volumes of GHG emissionsproduced by the building volume of Mount Everest,sector.are used in construction?Our estimates indicate that using this material could projects every year, reduce globalemissions by up to 80 percent compared resulting in huge volumeswith conventional cement,although BioZEment cannot of emissions. But a newbe used for all building applications in itspresent form. eco-friendly cementmayHowever, it will be able to contribute to the constructionhelp to reduce our globalsector?s collective efforts to reduce CO emissions.climate footprint. 2 ?The building industry emits huge volumes of CO ?, says 2SINTEF researcher Simone Balzer Le, who is part of across-disciplinary research team currently developing a biologicalcement called BioZEment. ?The manufacture of cement, which is a bindingagent in concrete, alone accounts for more than five per cent of globalgreenhouse gas emissions?.Bacteria-based concrete consists of sand, finely groundlimestone and two specific bacteria, mixed with water, urea andnutrients for the bacteria. Here is Simone Balzer Le in her lab. Photo:Hvard Egge.Bacteria instead of heatingConcrete generates huge volumes of greenhouse gases.This is why The process starts by mixing ground limestone particles researchers are looking into producing more eco-friendly forms of thisimportant construction material. Stock photo: Shutterstock. and sand inthe conventional way. But instead of heating the limestone, specificbacteria are added, which the No emissions ? no warming researchers have discovered close to alimestone quarry In conventional cement production, limestone is heatedin Verdal, Norway.to atemperature of 1450 degrees. The process is called calcination andresults in the release of huge volumes ofOur estimates indicate that using this cement couldgreenhouse gas (GHG) emissionsin the form of CO . reduce global emissions by up to 80 percent compared 2with conventionalcement.?There are currently many ways of reducing these volumes?, says Balzer Le. ?Our options include capturing?The bacteria produce organic acids, including lactic and the CO gas, partially substituting the cement withaceticacid?, says Balzer Le. ?These help to reduce the pH 2another binding agent, orfinding a way of makingvalue of the mixtureand so partially dissolve the cement without heating. This is the approach wearelimestone, releasing calcium ions andcarbonate?.using in the development of BioZEment?, she says. ?Step two involves mixing sand with another form of If the researchers succeed in advancing this lastbacteria in a mold and feeding this with the prepared www.ohiomasonry.org 4'