IN: Inspiration

SELF-CLEANING, SMOG-EATING CEMENT

While researching the development of an ingredient that would allow concrete to clean itself, cement producer Italcementi stumbled upon a now patented additive that has the potential to change the way we think about construction and its role in our environmental crisis.

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An Ever-changing Industry

The dome of the Pantheon, built over 2000 years ago, is not only the world’s largest unreinforced concrete dome, but one of the oldest existing examples of concrete application. Since its advent, concrete has grown into one of the world’s most important building materials. Naturally, the original recipe has changed over the years, incorporating new and improved ingredients and methods to help with durability and strength. However, the latest innovation in the world of cement and concrete is something a little different and has the potential to change the way we see construction irrevocably.

Introducing TX Active

Over the last decade, cement producer Italcementi has been working on a patented ingredient called TX Active. Concrete is easily tarnished by rain and pollution and requires a great deal of cleaning and attention to maintain its original colour. When applied to concrete, TX Active gives concrete the ability to clean itself, thus maintaining the original colour for longer, all on its own. It works through method called ‘photocatalysis'.

Photocatalysis

Strong sunlight or ultraviolet light has the ability to decompose organic substances over time. Photocatalysis works by speeding up a chemical reaction in the presence of light, destroying the colour of pollutants and accelerating the oxidation process. It does so through a natural mineral called titanium oxide which uses the sun’s rays to convert dirt particles and pollutants, such as nitrous oxide, into molecules like oxygen, water, nitrates and sulphates. Although photocatalysis was discovered in the 1970’s, it wasn’t until the early 90’s that the team at Italcementi discovered the great potential of titanium oxide in cement production.

An Unexpected Surprise

To everyone’s surprise – including inventor Luigi Cassar – self-cleaning cement not only cleans itself, but the air around it. Tests conducted at Italcementi showed that when a surface was treated with TX Active, the air around the concrete contained 80% less nitrous oxide than non-treated concrete.

The Jubilee Church

TX Active’s first major industrial application was the construction of Jubilee Church in Rome in 2003. 12 years on, the church still stands brilliantly white. Described as the ‘smog eating church’, Italcementi stand by their belief that Jubilee is just the first example of how TX Active can combat pollution.

Where to From Here?

TX Active is still more expensive than normal concrete and currently has not been applied on a sufficient scale to prove its efficacy. A concern raised is that the additive could work differently in alternative climates and environments; only time will tell if self-cleaning, smog-eating cement has an important role to play in the fight against climate change.

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