4.1 Executive Summary
The construction sector is dealing with immense amounts of raw material and various material innovations have already found their way into modern buildings. Consequently, recent developments in pioneering nanomaterials will take their share in the future architecture. However, the traditional construction industry tends to be low-tech oriented and extremely cost efficient. Furthermore, the actual number of nanotechnology application in construction is rather limited, since their innovative ideas are mostly targeted at surface effects and not the bulk structure. The most prominent example is Titanium dioxide which is already in use to improve material properties. It's photocatalytic activity can be used to break down dirt particles when exposed to sunlight. Self-cleaning windows and roof tiles have already been brought to market. Titanium dioxide may also be used to convert the entire surface of buildings into low-efficient but cheap solar cells harvesting constantly energy from sunlight. The extremely large surface to volume ratio of nanomaterials creates an unusual large total interfacial area. This so called specific surface area has also an enormous impact on the bulk structure of composite materials. Silicon dioxide or Silica is the most common nanomaterial in today's construction industry in terms of production volume per year. Other nanomaterials such as carbon nanotubes for example are being discussed intensively as potential candidates for future construction materials but have no significant influence at present.
Concrete is the most abundant material within the construction industry. With a production volume of 14 billion tons per year, it is also the most widely used man-made material on earth. Due to its complex chemical composition it is a natural nanomaterial which is constantly in use since ancient Roman times. However, the physical properties of concrete can be improved and are a matter of intensive R&D.
The materials cement and concrete can be found exclusively in the construction sector. For this reason and for their outstanding importance for a sustainable development in the future they are treated separately in the following. Especially the CO2 emission connected to the production of Portland cement clinker has been discussed controversially.
Besides cement and concrete also steel and glass have an enormous significance in the construction industry. Especially the use of sheet or flat glass has gained importance in non-residential buildings. In this regard coatings have been investigated intensively. Especially the use of ultra-thin nanocoatings to control the heat transfer through window panes is crucial for a sustainable development of future buildings. In addition the use of photovoltaic cells has grown constantly in recent years. They make use of smart anti-reflective nanocoatings to improve the efficiency of solar cells. A detailed description of solar cells can be found in the "Energy" sector.
The construction sector described in the following has not been classified to the different materials except for cement based materials. A detailed description of most nanomaterials can be found in "Chemistry and Materials". For this reason the following has been sorted by application and societal needs. Besides "cement based materials" and "coatings" an energy efficient and sustainable production of materials and the environmental protection will be crucial for future technologies and innovations ("Sustainability and Environment"). Building safety especially with respect to fires is a constant threatwhich can be addressed by suitable nanomaterials ("Living comfort and Safety").
Finally, "civil and underground engineering" especially with respect to paving has been discussed in terms of using innovative nanomaterials in recent years.
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