Known as the most popular building material worldwide, concrete is an old discovery. It was known to the ancient cultures of Egypt and Babylon who used a blend of pebbles and clay to make firm structures. The renowned tourist attraction, the Great Wall of China, consists of blocks that were joined together with cement. In modern society cement, which has tiny particles of aggregate, is mixed with water and cement incorrect ratios.
While concrete is so commonly used, the major producer of Portland cement is thought to contribute to earth’s carbon emissions by five percent. Hence, efforts are being made to make concrete cement green.
Camfree, a British organization, has made their move by creating their cement-free concrete. This cement uses bonding material called ground-granulated blast furnace slag. It is a bi-product from the steel industry. According to Cemfree, if their concrete had been the one used to construct the Empire State Building, up to 13,319 tonnes of CO2 emissions would have been avoided. While several in the construction industry don’t trust Cemfree’s cement, tests have shown that it performs almost as great as the conventional cement concrete.
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The Taktl UHPC (Ultra-high-performance concrete) is yet another promising product. When compressed, Taktl stays strong as it has many tiny particles that are packed together. Compared to ordinary concrete, Taktl needs less water allowing builders to achieve strong structures while using less of it. According to Taktl co-founder, Lauren Flannery, their concrete was made in conjunction with G.TECZ (a Germany facility).
Then there is the bioreceptive concrete, created by Dr. Sandra Manso-Blanco. Bioreceptive concrete allows growth of moulds. However, together with the BiotA lab(at Bartlett School of Architecture), Dr. Manso-Blanco has come up with a four-layered structure: regular cement concrete, waterproofing, bioreceptive concrete and top layer for absorbing and storing water.
Only these three products have been developed to make concrete cement green.