Several European associations of the concrete industry (BIBM, ERMCO, UEPG, EUROFER, and CEMBUREAU EFCA), in collaboration with the Dutch environmental consultant INTRON BV studied the possibility of minimizing the environmental impacts of concrete elements. One of the objectives of this study, was to develop the tool EcoConcrete, in order to evaluate the environmental impact associated with a particular element of reinforced concrete (Schwartz – entruber 2005). Some authors (Gerrilla et al. 2007) compared the performance of houses built with wooden and concrete structures, reporting that the latter had an overall environmental impact only 21% higher than the former. Xing et al. (2008) compared the performance of two office buildings with different structures (reinforced concrete and steel) and found that the steel structure consumes 75% energy compared to the concrete structure and is responsible for half of the emissions GHGs, however, in operational terms the concrete structure exhibits a much lower energy consumption having an overall favorable environmental performance. Marinkovic et al. (2010) studied concretes with and without recycled aggregates and found that their environmental performance is dependent on the transportation distance, regardless of whether they are recycled or not.
Under the project Beddington Zero (Fossil) Energy Development (BedZED), 82 households and 3,000 m2 of commercial or live/work space with low environmental impact were built in South London. The choice for the construction and building materials in the BEDZED project was made using the BRE. Envest eco-points system (Figs. 11.5, 11.6).
Desarnaulds et al. (2005) also used the BRE. Envest eco-points system to compare different sound insulation materials mentioning that the best environmental performance is associated with recycled paper, followed by rock wool and finally by polystyrene. Nicoletti et al. (2002) showed that ceramic tiles have an environmental impact throughout its life cycle that is over 200% higher than the environmental impact of marble tiles. These results are confirmed by more recent investigations (Traverso et al. 2010). Jonsson (2000) assessed the environmental performance of three floor covering materials using six different approaches:
• An LCA
• An Eco-label (The Swan)
• Two eco-guides (EPM and the Folksam Guide)
• An EPD
• An environmental concept (Natural Step).
Waste disposal Water extraction H Minerals extraction Щ Fossil fuel depletion Eutrophication to water Щ Ecotoxicity to water
■ Human toxicity to water h Photochemical ozone m creation potential
Human toxicity to air
■ Acid deposition Climate change
□ Waste Disposal
Fig. 11.6 Comparison of the environmental profile of different framed windows (BEDZED2002)
The results showed that while the LCA considers all environmental impacts in a similar way, some forms of sustainability assessment allow prioritizing certain impacts, either during production the phase or during the application of the material in the building. The results also show that only the LCA and the ecoguides allow the development of product rankings. Regarding the aggregation of the results, the eco-label has the best performance and the EPD gets the worst, making it difficult to understand the performance of a particular product.
Although LCA is the most appropriate way to scientifically evaluate the environmental performance of a given material, it is very time consuming and has some uncertainties. Besides the success of LCA is dependent on the existence (in each country) of lists on the environmental impacts associated with the manufacture of different materials and of the different construction processes. Another drawback of LCA is the fact that it does not take into account possible and future environmental disasters associated with the extraction of raw materials. This means that for instance the LCA of the aluminum produced by the Magyar Aluminum factory, the one responsible in October 2010 for the sludge flood in the town of Kolontar in Hungary, should account for this environmental disaster. Similar considerations can be made about the construction materials that were processed or transported using oil extracted from the Deepwater Horizon well in the Gulf of Mexico. Or even about the materials that were processed using the electricity generated in the Fukushima nuclear power plant. Only then construction and building materials will be associated with their true environmental impact. As for eco-labels they allow a more expedient information for a particular environmental performance, although its value is dependent on the entity and the assumptions that were on the basis of its allocation. Although eco-labels exist for almost 30 years, its use is still neglected by the construction materials market. In fact only a tiny fraction of the current commercial construction materials already have eco-labels. The emphasis in the respect for environmental values will lead to an increase in the number of material producers using eco-labels as a means of differentiation. As regards EPDs they have disadvantages similar to LCA, so it is not expected that in the coming years there may be an accelerated growth of products with EPDs.