Air-purifying concrete could clean up Dutch cities

5th August 2008, Comments 1 comment

A newly-developed air-purifying concrete may be the answer to cleaner roads in Netherlands.

5 August 2008

THE NETHELRANDS - The air in Dutch cities could be kept clean by the road itself in future.

In a trial in the city of Hengelo in the east of the Netherlands, a street is being paved with air-purifying concrete to test an invention developed by the University of Twente.

Car exhaust fumes contain nitrogen oxide. These chemicals are responsible for causing acid rain, which can damage buildings and harm forests. They also help to produce smog, or ground-level ozone, which can cause serious respiratory problems for city-dwellers.

The paving stones developed by the Twente team are based on a Japanese invention. They contain a titanium dioxide-based additive, which under the influence of sunlight converts nitrogen oxide into nitrates. Washed away by rainwater, these can then act as fertiliser. The new paving stones also repel dirt, so the street stays clean.

The paving stones work perfectly in the lab, so it was decided to see how they would work in practice. A busy Hengelo street will be divided into two sections, one half with air-purifying paving stones and the other half with conventional ones. Researchers will then compare the air quality in each section.

The new road should be finished by the end of 2008, and the first results of the test are expected in summer 2009.

[Radio Netherlands / Expatica]

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1 Comment To This Article

  • HistoryTechDoc posted:

    on 6th August 2008, 13:30:16 - Reply

    In principle this "air-purifying concrete" concept sounds interesting.

    May I add just two observations: firstly titanium-dioxide from my experience in the paint industry is very important in the production of paint. The more of it, the better the quality of the paint. (It would be helpful to Dutch consumers, as it is to those in the U.S., if the percentage of titanium-oxide were required to be printed on every paint product label, so that buyers would have a better idea of the quality of the paint that they are purchasing).

    It should be, furthermore, pointed out that titanium-dioxide is, however beneficial, a very expensive component for any use (and perhaps the underlying reason why it has not been voluntarily added to Dutch paint product labeling containing same).

    My larger point, however, is that the truly large source of CO2 used in producing concrete and cement is released in its manufacture, which accounts for approximately 20% of all manufactured products from what I have read.

    As I understand it, fly-ash containing alkali emitted in steel production (just about all steel production) can be economically used to reduce such CO2 emissions in concrete and cement production. Furthermore, there is at least one firm located in the NL that has proven the concept in producing high-quality concrete and cement with fly-ash. (No need to go to Japan when there is still much local expertise that has not as yet been utilized).

    It baffles me how with the incredible high levels of CO2 emissions throughout Europe that more is not done to provide more funding for trial productions of alkali-based additives as has been done for decades past in Eastern Europe with notable success.