Backed up by third party tests, Thermal Recycling claims to have shown that its Calmag material is an effective cement substitute.
Calmag is made from cement roof sheets containing chrysotile asbestos. Thermal treatment changes the chemical and physical composition of the asbestos, producing an asbestos-free material that is then crushed. The end product can be used as a sustainable aggregate that is particularly useful for road building, it is suggested.
Thermal Recycling opened its demonstration plant in Wolverhampton in September 2020, supported by a government grant, to convert asbestos roofing on an industrial scale, in a commercially viable and environmentally safe way.
The project involved making prototype construction products from Calmag, named because it is comprised of calcium, aluminium and magnesium as silicates, carbonates, sulphates, and oxides.
Two commercial certified laboratories then conducted extensive technical assessments of the product’s characteristics, including compression strength, load-bearing capability, and water permeability. The research showed that Calmag is effective as a cement substitute. Market research was also conducted in different sectors to identify potential users of the product.
The project concluded that the best use for Calmag is as a low-carbon cement substitute.
Thermal Recycling chairman Graham Gould said: “This was really important research for Thermal Recycling; identifying a market for Calmag defines us as a circular economy business. This also reinforces our vision for the company; we can not only divert asbestos away from landfill, but also offer a sustainable product to the construction sector. There is a pleasing symmetry to being a business that is involved in removing the problem of asbestos for future generations and being able to use the converted material which contributes to creating a better future for that generation.”
Approximately 60% of asbestos taken to landfill is in the form of roof sheets. Removing asbestos roof sheets involves putting them in a skip and sending to landfill. There has been no alternative – until now, it seems.