A lead engineering investigator into biogenic limestone-based Portland cement has gone out on a limb and declared his team has found the best solution for the concrete and cement industry to address its carbon problem.
Associate Professor Wil Srubar of the Materials Science and Engineering Program at California University Boulder leads the Living Materials Laboratory with a team exploring how to grow limestone particles using microalgae to produce concrete with positive environmental benefits.
“We see a world in which using concrete as we know it is a mechanism to heal the planet … [and] … we have the tools and the technology to do this today,”. Professor Srubar said.
So assured is the team of their solution, they received a USD 3.2 million grant to develop and scale up the manufacture of biogenic limestone-based Portland cement. In their studies, the research team found that replacing quarried limestone with biologically-grown limestone (a natural process which some species of calcareous microalgae complete through photosynthesis), creates a net carbon neutral way to make cement. The carbon dioxide released into the atmosphere equals what the microalgae already captured.
“By using biogenic limestone instead of quarried limestone as the filler, Portland cement could become not only net neutral but also carbon negative by pulling dioxide out of the atmosphere and storing it permanently in concrete,” the team explained.
“If all cement-based construction around the world was replaced with biogenic limestone cement, each year, a whopping two gigatons of carbon dioxide would no longer be pumped into the atmosphere and more than 250 million additional tons of carbon dioxide would be pulled out of the atmosphere and stored in these materials.”