Concrete: is there an alternative?

Updated 9:14 AM ET, Thu May 22, 2014
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Had enough of concrete blocks? The hugely useful (but harmfully polluting) material responsible for the rise and rise of the modern city can no longer claim to be the only material available to architects. courtesy peter trimble
Edinburgh College of Art student Peter Trimble has created a possible solution using little more than sand and urea. Dupe is almost as structurally strong as concrete but produces no greenhouse gasses. Trimble's system is not yet ready for production, but similar concrete alternatives are already available to builders... courtesy peter trimble
Builders laying the concrete foundations of the Wilshire Grand Tower -- the skyscraper set to become Los Angeles' tallest building -- substituted a quarter of the cement with "Fly Ash" The waste ash from coal combustion at power plants in Utah and Arizona increases the durability of concrete while offsetting the CO2 cost of cement production. courtesy Wilshire Grand Project
Japanese firm TIS & Partners have created a new building material called "CO2 Structure," dreamed-up in the aftermath of the March 2011 Japanese Tsunami as an emergency rebuilding material than can be put in place quicker than slow-drying concrete. By injecting carbon dioxide into a silica (sand and quartz), they managed to developed a carbon-negative building material with twice the tensile strength of brick. Ken Ishii/Getty Images
Natural building materials are a popular choice for those looking to cut CO2 emissions. Making bricks from hemp results in a net decrease in carbon dioxide levels, as the growing plant takes in CO2. These bricks are made of hemp combined with clay, while Hempcrete (a mixture of hemp and lime) is sold internationally as a thermal walling material. BERND SETTNIK/AFP/Getty Images
Ecovative already make packaging from agricultural waste and mushroom "mycelium" -- and their next project is building materials. Founder Eben Bayer describes mycelium as "essentially the 'roots' of mushrooms" and says it is very good at binding together organic materials, which could one day make building blocks. courtesy peter trimble
Another natural material with carbon negative production: lowly straw is making a return to construction. In America's "Nebraska Method" homes, straw bales are used as a both a structural and insulating material. Companies such as UK's ModCell manufacture pre-fabricated wall and roof panels from straw. JEAN-FRANCOIS MONIER/AFP/Getty Images/file
Traditional building materials such as mud and cob -- a mixture of sand, clay, straw and earth -- have been proposed as a non-polluting alternative building material for small buildings, such as households. One man from Oxford, UK claims to have built a Hobbit-like home from cob for less than $250. ORLANDO SIERRA/AFP/Getty Images/file
Recycled materials are making up an increasing part of building blocks. Enviroblocks are made from over 70% recycled aggregates, bound with cement, while Durisol units contain 80% recycled woodchip, which is wrapped around steel bars for strength. JEAN-FRANCOIS MONIER/AFP/Getty Images
Clay blocks with "honeycomb" structured cross-sections -- often known as Ziegel Blocks -- have been common in some parts of Europe for decades, but are now spreading far beyond. Manufacturing blocks from clay rather than concrete means less CO2 emissions from production, while the blocks insulating characteristics can cut a building's energy costs. Jorge Guerrero/AFP/Getty Images
Cutting concrete pollution could mean rethinking our approach to construction from start to finish. Housing made from recycled shipping containers has popped up all over the world and provides one low-cost, low-emission solution. Are there others? MAARTJE BLIJDENSTEIN/AFP/Getty Images/file