Self-Cleaning Concrete
Concrete Technology
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Building a Better (Cleaner) World in the
21st Century
 Self-cleaning
buildings and pollution-reducing roadways: These may sound like
futuristic ideas, but they are realities of some of today’s
concrete. Recently introduced formulations of cement are able to
neutralize pollution. Harmful smog can be turned into harmless compounds
and washed away. Anything made out of concrete is a potential application,
because these cements are used in the same manner as regular portland
cements. These products provide value through unique architectural
and environmental performance capabilities.
Proprietary technology (based on particles of titanium dioxide)
is what makes this cement special. The technology can be applied
to white or gray cement and it works like any other portland cement:
it can be used in all varieties of concrete, including plaster.
Presumably, applications for mortar might be beneficial, too., although
the mortar has a smaller surface area. The only difference is that
it is capable of breaking down smog or other pollution that has
attached itself to the concrete substrate, in a process known as
photocatalysis. As sunlight hits the surface, most organic and some
inorganic pollutants are neutralized. They would otherwise lead
to discolored concrete surfaces.
The titanium-based catalyst is not spent as it breaks down pollution,
but continues to work. Typical products are oxygen, water, carbon
dioxide, nitrate, and sulfate. Because rain washes away the pollution
from the concrete surface, buildings stay cleaner and do not require
chemical applications that are potentially harmful to the environment.
Maintenance costs are reduced. This is true even for buildings in
highly polluted locations—one noted application is the Air
France headquarters at Roissy-Charles de Gaulle International Airport
near Paris, a white concrete building that has remained white. Another
is the Church of the Year 2000 in Rome.
Clean buildings are great: A perhaps even more astounding environmental
benefit is the potential for cleaner air. Concrete products that
are exposed to sunlight throughout their life, like precast building
panels, pavers, and roof tiles, are especially suited to manufacture
with photocatalytic cement. For instance, city streets made with
special pavers are capable of reducing the pollution at its source—where
it comes out of the tailpipe.
There are two major cement companies distributing this type of cement
in the United States. Italcementi, the Italian parent company of
Essroc Cement, originally brought this product to market. They have
recently licensed Heidelberg Cement to produce and market
the material in Europe and North America. Brand names for the white
cement are TX Active® and Tiocem.
Click
here to buy our recently updated bibliography of photocatalytic
concrete articles, reports, conference papers, and patents,
identified through searches of online scientific databases as well
as the Library’s collection.
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