5 Concrete constituents as example for the release of dangerous substances
5.7 Proposals for implementing the Essential Requirement No. 3 for concrete
Cement
Cement is a mandated construction product for which there has been many years of experience in terms of its composition and the use of concrete constituents. Here, however, it needs to be differentiated between cement that is manufactured without using wastes19 and cement that is manufactured with the use of wastes.
Cement that is manufactured without wastes is suitable for inclusion in the list of WFT products (WFT – Without Further Testing), as existing studies on the content and leaching give no cause for concern that there might be an environmentally relevant release of dangerous substances. However, this still needs to be verified for all types of cement and for the release of organic substances. If cement is included in the WFT list, the composition of the cement needs to be precisely specified in the product standard and the standard should state that no wastes may be used.
Cement that is manufactured with the use of wastes requires far more extensive regulations in the product standard. If wastes are used as secondary raw material or secondary fuel, and if there is also sufficient practical experience in the form of existing test parameters, then these wastes should be listed in the product standard with the corresponding test parameters to be determined. It should be indicated in the standard that the scope only refers to the wastes listed.
If wastes are used for which there is no experience in the form of test parameters, the manufacture of this cement shall be classified as being subject to approval, as the scope of the testing for the product to be approved can be specified by an expert committee.
Aggregates
The term "aggregates" encompasses a construction product group that can consist of very different materials.
Natural aggregates of mineral origin are suitable for inclusion in the list of WFT products.
However, the radioactivity of natural stone such as granite must still be taken into account, which was not taken into consideration by this research project. The fact that the heavy metal content of natural stone sometimes lies above the limit values for soil, which define a no risk level, needs to be discussed.
It can be considered whether the manufactured aggregate crystalline blast furnace slag is a WFT product as existing studies on content and leaching provide no indication that there is a significant release of dangerous substances. Test parameters should be specified in the product standards for the aggregates melting chamber granulates and non-ferrous slag. The scope of the product standard should indicate that the standard is only to be used for the named aggregate.
If slags from waste incineration plants are used as aggregate, these should be classified as requiring approval due to their significantly varying composition. This classification as requiring approval also applies to all other wastes for which there is no experience and, correspondingly, no test parameters.
19 Wastes describes substances that are listed in the European Waste Catalogue [67] as waste or hazardous waste. It must be decided for each individual case whether this waste also fulfils the definition according to Art. 1 a) of the Waste Framework Directive 75/442/EEC [70], whereby wastes are defined as any substance or object which the holder discards or intends or is required to discard.
No classification can be currently made for heavyweight aggregates, as there are no results from leaching tests.
Lightweight aggregates from natural materials and products which were manufactured without the use of wastes can be discussed in terms of being WFT products. The same restrictions apply as with the aforementioned natural aggregates.
If wastes are used for which experience and test parameters already exist, such as, for example, furnace sand, then these wastes and the specification of the parameters should be listed in the product standard. Wastes for which no test parameters are available should be made subject to approval.
Various specifications are required in the product standard for using recycled aggregates.
Recycled aggregates from suspected contamination sites should be excluded from the scope of the product standard. Due to the considerably varying contamination of such aggregates, these should be made subject to approval, as here the scope of the testing can be specified by an expert committee for the specific product. For all other recycled aggregates, the scope of the parameters to be determined should be listed in the product standard. In order to avoid contamination by organic substances, the foreign matter content of the non-mineral material should be specified in the product standard.
Concrete additions
Fillers, pigments and fly ash were examined as concrete additions.
Fillers are suitable for inclusion in a list of WFT products, since, with the exception of limestone intercalated with ores, there was no indication of any risk to the environment.
Exceptional cases should be listed in the product standard and the respective procedure indicated, such as the carrying out of leaching tests.
Inorganic pigments should be discussed in terms of inclusion in the WFT list as there was no indication of there being any risk to the environment. However, this does not apply to organic pigments since, because of the lack of leaching tests, no statements can be made. One possibility here would be to specify the product standard only for inorganic pigments and make organic pigments subject to approval until enough experience has been gained on the leaching behaviour of these substances.
When using coal fly ash without the co-combustion of wastes, test parameters must be specified in the product standards. If wastes (secondary fuels) are co-combusted during the production of fly ash, this fly ash should be classified as being subject to approval. If there has already been many years of experience in co-combusting wastes such as, for example, sewage sludge and petroleum coke, it should be discussed whether a positive list of wastes can be included in the product standard as has happened with the current draft version of the European fly ash standard DIN EN 450-1. Owing to the highly differing composition, fly ash from waste incineration plants domestic or commercial waste should be made subject to approval.
Concrete admixtures
Because of the lack of leaching tests, it is not yet possible to classify concrete admixtures.
6 Floorings as example of the release of dangerous substances in indoor spaces
Floorings are mandated construction products, which, owing to their large surface areas, are potentially one of the most important pollution sources in indoor spaces. Here it is not just the emission of volatile organic substances into the indoor air that is relevant but also the emission of semi-volatile organic substances – which are mostly attached to house dust – and the absorption of substances through skin contact. For example, small infants come into considerable contact with floorings as they crawl about during the first years of their lives.
They can even absorb chemical compounds, such as plasticisers, pigments and biocides, via house dust and through their skin coming into contact with the flooring20.
Floorings form a construction product group that uses numerous different materials and substances. The following table provides an overview of floorings and classifies them according to their composition and surface.
Table 24: Classification of floorings
Organic Inorganic
Textile Resilient Rigid
• Pile carpets
• Needled floor coverings made of natural and artificial fibres
• PVC floorings
• Polyolefin floorings
• Linoleum floorings
• Rubber floorings
• Cork floorings
• Laminate floorings
• Wood floorings
• Ceramic tiles
• Natural stone floorings
• Artificial stone floorings
Because of the enormous diversity of materials, the following section will only consider organic materials (textile, resilient and rigid floorings from wood and wood-based panels including laminates).
In order to assess the dangerous substances released from floorings, a comprehensive concept shall be presented that describes procedures for assessing the health effect of construction products in indoor spaces. The composition of various types of floorings will also be explained in detail. The section "Content/Release of dangerous substances" presents test results from emission measurements in test chambers and indoor air, and provides information on substances that are likely to be released due to their chemical properties. The resulting recommendations should be taken into account when revising the technical specifications for floorings in order to eliminate any danger to users of construction works. In addition to the recommendations, the proposals for the implementation of the Essential Requirement No. 3 "Hygiene, Health and the Environment" also indicate how this implementation can be conducted for standardised and approved floorings. A detailed description of the testing methods for determining the emission in indoor spaces shall be dispensed with because, in contrast to the diverse testing methods for leaching in soil and groundwater, European testing methods already exist that only require harmonisation.
20 For the association between children’s asthma and allergies and exposure to softening agents from PVC flooring and other plastic products in the indoor climate see:
http://ehp.niehs.nih.gov/members/2004/7187/7187.html