Luigi Cassar, Gian Luca Guerrini and team

Self-cleaning concrete

Technical field
Civil engineering
Italcementi S.p.A.
Thanks to an invention from chemist Luigi Cassar, building exteriors can now not only stay cleaner longer but also help neutralise pollutants and improve air quality. Just a thin layer of an innovative cement coating combined with sunlight enables cleaner facades – and cleaner air in the cities that surround them.

Finalists for the European Inventor Award 2014

Together with his team at the Italian cement manufacturer Italcementi S.p.A., Luigi Cassar developed an innovative new cement mixture that is self-cleaning and purifies air. The cement uses sunlight to break down pollutants into less harmful substances. This way, it not only lastingly prevents the effects of pollution; it also combats pollution itself.

Cassar and his team achieved this breakthrough by enriching cement with titanium oxide minerals, which oxidise with sunlight to break down pollutants before they can bind with the surface and cause discolouration. The photocatalyst compound can also be incorporated into mortar, paint, plaster, and even roads .

Societal benefit

Walls covered in the self-cleaning cement cut levels of NOx – a collection of nitrogen compounds that are harmful to human health and create low-lying smog – in the surrounding air by as much as 80%. They also reduce other known toxic substances, including lead, carbon monoxide and sulphur dioxide. And because Cassar’s compound keeps buildings’ facades clean and bright, it improves not only the physical health but also the mental wellbeing of urban citizens.

Economic benefit

Italcementi Group is the fifth largest cement producer in the world. The Group companies combine the expertise, knowhow and cultures of 22 countries in 4 Continents, boasting an industrial network of 46 cement plants, 12 grinding centres, 6 terminals, 420 concrete batching units and with an overall staff of about 18,500 people. In 2013 Italcementi Group sales exceeded 4.2 billion Euro.

One of the major drivers for the cement market is steady and consistent growth in construction industry. Strong prospects in the construction industry of emerging economies such as China, India and Brazil are expected to increase the demand for cement. Asia Pacific is the largest consumer of cement market followed by North America and Europe . The ‘Key Trends and Opportunities to 2017’ research report says worldwide market value for concrete and cement industry was US$ 324.4 billion in 2012.

How it works

The self-cleaning cement developed by Luigi Cassar and his team is based on photocatalytic ingredients: substances that react with sunlight. The photocatalysts are added to the concrete mixture mainly in the form of anatase – one of the three mineral forms of titanium dioxide.

Using sunlight, photocatalysts oxidise (combine chemically with oxygen) organic and inorganic substances, promoting faster decomposition of pollutants and preventing them from accumulating on the surface of a building. Nitrates and sulphates on the cement are easily washed off with rainwater, leaving the surface without the need for chemical cleaning.

The inventor

After studying chemistry in Rome in 1961, Cassar worked for the Italian company Montedison and at the University of Chicago. He held managerial positions in various R&D departments and has taught courses as a professor at the Universities of Sassari, Parma and Bologna. Cassar holds 80 patents and is the author of 95 scientific publications. After joining Italcementi in 1991, he spent a decade developing construction materials that contain photocatalysts.

Did you know?

Having developed a lasting and environmentally friendly remedy to dirty facades, all Cassar’s team needed was a compelling case study. The opportunity presented itself in 1996, with architect Richard Meier’s stunning modern design for the Dives in Misericordia Church Project in Rome . The church featured tall, pure white “sails” thrusting skyward, fashioned from concrete. The Vicariate of Rome was keen on maintaining the building’s radiance, and Italcementi was able to offer a solution: Luigi Cassar’s self-cleaning cement.

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