Acrete: lighter, stronger, and more environmentally friendly than concrete

In recent years, people have become more and more aware of the polluting consequences of making concrete. However, finding a good alternative isn’t all that easy. Here at Materia, we have discussed cement and concrete made from CO2. Now, there is a new, more environmentally friendly alternative to concrete, called Acrete. Developed by Jinhong Zhang, associate professor of mining and geological engineering at the University of Arizona, the substitute building material uses three times more fly ash, a pollutant, than concrete, while being lighter and stronger than the traditional building material.

Fly ash serves as an additive in the production of Portland cement-based concrete products, but it only tends to make up only about 30 per cent of the solid material. In Acrete – a name that derives from a contraction of the words Arizona, home of the university, and concrete – uses nearly 100 per cent fly ash as solids in the end product, without the addition of cement, the real culprit of pollution.

According to the press release, Acrete can have as much as three times the compressive strength of cement and twice the flexural strength. It also repels water, and the workability of the material can be controlled by tweaking the recipe.

Coal-fired plants in the United States alone produce about 130 million US tons (118 million tonnes) fly ash. While fly ash is already being used in the fabrication of fly ash bricks, much of it is still disposed of in mounds where wind and erosion can disperse it. Moreover, these heaps lead to high monetary, environmental and ecological costs.

Using more fly ash in the fabrication of concrete will have a lot of advantages. Not only for the environment, although that is a huge plus, but as the fly ash is readily available, it also makes the production of Acrete cheaper than ordinary concrete.

Photo Acrete: Paul Tumarkin/Tech Launch Arizona