Additives in concrete paving could enable it to reduce elevated levels of traffic exhaust emissions, according to concrete paving industry group Britpave.
Britpave has said that addition of titanium oxide in concrete could allow it to absorb nitrogen dioxide emissions from road traffic.
“The addition of titanium dioxide to concrete means the concrete actually eats pollutants,” said Britpave chair Joe Quirk.
Titanium dioxide (TiO2) is a photocatalytic material that reacts in sunlight to absorb nitrate oxides and convert them into harmless nitrates. Quirk has said that this could be applied as a pavement spray or as an additive to concrete to combat pollution and would add only 5% to 10% to the cost of a concrete road.
Quirke points to research carried out by the Eindhoven University of Technology in the Netherlands that found NO2 reduction of 35% to 40% in areas paved in concrete featuring TiO2. Researchers at the Public University of Navarre, Spain, are developing a nanoparticle coating for concrete uses photocatalytic reaction to reduce up to 90% of nitrogen oxides, 80% of hydrocarbons and 75% of carbon monoxides. In Segrete, Italy, a road treated by Essroc Italcementi with a TiO2 pavement spray resulted in a NO2 reduction of 60%.
According to Quirke, use of the technology by Highways England could be a useful solution to come out of its review of measures to reduce elevated levels of traffic exhaust emissions.
“Pollutant eating concrete roads may sound like science fiction but they are a very real solution that should be considered”, said Quirke. “Plus they are the not the only environmental benefit of concrete roads. In addition, concrete roads can also be self-heating to reduce ice and snow-build-up, self-healing to reduce the need for repair and maintenance and energy conductive for easy wireless charging of electric vehicles as they travel over them. Plus, their thinner pavements, longer performance life and reduced maintenance means a reduced life cycle carbon footprint.”