Concrete Evidence for Better Cement

We are seeing an uptick in activity in the development of better, lower footprint building materials that are capable of being mass produced on a scale at which they will continue to be needed.

Portland cement — the dry component that along with sand, gravel and water goes into making concrete — is one of the most important, widely used and most in-demand of raw materials for construction around the world. Projected demand for cement is expected to be 50 percent higher than current levels by 2020. The problem is that cement manufacturing is responsible for about 5 percent of annual greenhouse gas emissions. You might think that it has to do with all the fuel required to drive the process, and while that is part of it, most of the carbon dioxide given off by cement manufacturing is due to the geochemical changes that take place as calcium carbonate-rich limestone becomes cement.

With a backlog of overdue infrastructure upgrades here at home, and with development moving at a sprightly clip in China, India and other parts of the world, two things are clear: we will continue to need lots of cement, and we need to continue efforts to minimize the carbon footprint associated with traditional manufacturing.

We've brought you news of developments on this front previously. Last month we wrote of an alternative geopolymer material that incorporates fly ash, an industrial byproduct of burning coal. And last year we presented a piece pointing to a California pilot project that involved mixing industrial flue gases with seawater to generate raw material feedstock as well as taking carbon dioxide out of the air with the end result of cement that is carbon negative.

News arrived late last year through The Guardian of another approach that is reportedly carbon negative. Engineers at Novacem in England have developed an alternative material that relies more on magnesium than on calcium silicates. No carbon dioxide is given off during manufacturing, and more carbon dioxide is absorbed as the concrete made from it hardens, rendering their material carbon negative.

And this past week, we also learn from The Guardian of a material called Liquid Granite, touted to have the potential to replace a sizable portion of conventional Portland cement. While the exact recipe is being kept under wraps as research and development proceeds, Liquid Granite's developer tells The Guardian that the new concrete uses very little Portland cement, with the remainder made from mostly materials reclaimed from industrial waste streams (presumably fly ash is part of the Liquid Granite mix).

Whether there will be a single breakout approach, or if we use several different alternatives, we appear to be well on the way to developing materials that will help put our infrastructure and our atmosphere on more solid ground.

Photo courtesy of katorisi, via Wikimedia Commons