As pollution increases in our rapidly developing world, environmental protection will need to rely on new innovations to remove pollutants. A Highways England review follows increased concerns about the elevated levels of nitrogen dioxide (NO2) from increased traffic levels which on motorways have increased by almost 25% over the last 20 years. Possible solutions include a network of 9m-high pollution barriers installed at key locations across the strategic road network, or the use of temporary 60 mph speed limits at peak times. However, there may be less visually intrusive answer than 9m high barriers.
According to Britpave, concrete paving industry group, additives in concrete paving could enable it to reduce elevated levels of traffic exhaust emissions. The addition of titanium oxide (TiO2) to concrete could allow it to absorb nitrogen dioxide emissions from road traffic. Highways England is reviewing measures to reduce elevated levels of traffic exhaust emissions … the answer could be at their feet believe Britpave.
Joe Quirke, Chair-Britpave said, “Highways England may well want to look at new concrete technology developments that offer the exciting possibility of concrete roads that absorb NO2 pollutants. The addition of titanium dioxide (TiO2) to concrete means the concrete actually eats pollutants.”
Titanium dioxide (TiO2) is a photocatalytic material that reacts in sunlight to absorb nitrate oxides and convert them into harmless nitrates. 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.
Urban Transport News-New Delhi, India also reported that additives to concrete absorb harmful exhaust emissions. Countries around the world are looking to reduce harmful vehicle emissions. Although nitrogen dioxide is not classified as a greenhouse gas, it is till a harmful air pollutant, causing health and environmental damage. When added to concrete as a spray on concrete pavements, research has shown that it converts harmful oxides into inert nitrates. Where concrete pavements have been impregnated with titanium oxide, levels of nitrogen dioxide are reduced by 40%.
Titanium is commonly integrated into roofing tiles, structures, and automotive design in internal engine components, including valves and connecting rods where its high strength and resistance to corrosion are highly valued. Due to its excellent strength-to-weight ratio and superior resistance to heat, corrosion, rusting and pitting, TiO2 is increasingly being chosen for exhaust systems—lighter components that can help reduce fuel consumption, is more cost-efficient, and possesses other qualities that are being used in innovative ways to reduce harmful emissions from traffic. It proves to be a sustainable solution.
Quirke points to research carried out by the Eindhoven University of Technology-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
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.
Quirke added, “Pollutant eating concrete roads may sound like science fiction but they are a very real solution that should be considered. Plus they are the not the only environmental benefit of concrete roads. In addition, concrete roads:
• self-heating to reduce ice and snow-build-up
• self-healing to reduce the need for repair and maintenance
• energy conductive for easy wireless charging of electric vehicles as they travel over them
• thinner pavements
• longer performance life
• reduced maintenance means
• reduced life cycle carbon footprint.”
For important Links, please go to:
New Civil Engineer online magazine article titled “Concrete additives could ‘eat’ transport-related emissions”: www.newcivilengineer.com/latest/concrete-additives-could-eat-transport-related-emissions-04-08-2020/#:~:text=Britpave%20has%20said%20that%20addition,said%20Britpave%20chair%20Joe%20Quirk
Britpave webpage titled “Concrete roads could eat traffic pollutants”: www.britpave.org.uk/news/Concrete-roads-could-eat-traffic-pollutants/125140
Urban Transport-India online article titled “Titanium and its Compounds in Sustainable Transport Applications”: www.urbantransportnews.com/news/titanium-and-its-compounds-in-sustainable-transport-applications