ECN publication
Ontwikkeling van een kortdurende test voor vormgegeven bouwstoffen, geïmmobiliseerde afvalstoffen en andere monolithische materialen
Published by: Publication date:
ECN 1998
ECN report number: Document type:
ECN-C--98-055 ECN publication
Number of pages: Full text:
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The tests of long duration, as specified in the Dutch Building MaterialsDecree, are inappropriate for a quick evaluation of the environmental properties of construction materials and waste materials in the framework of quality control. For monolithic materials and prefabricated construction products the tank leach test is applicable. The mechanism of leaching, that forms the basis for this test does allow a shorter testing cycle. However, interference of initial effects not related to the dominant leaching mechanism need to be taken into account. The present study deals with these interferences, which can be reduced significantly by modifying the test conditions. Attention has been given to such aspects as wash-off effects, minimum volume for analysis, improved analytical sensitivity, avoiding depletion, rapid water saturation, agreement with the NEN 7345 and repeatability of a short test. For a wide range of materials the relation between the short and the long test procedure is such that the proposed short test can be used beneficially in material evaluation for quality control purposes. Deviating leaching behaviour can also be identified by the short test. Only in case of light weight concrete a higher leach rate is observed resulting from the higher degree of saturation that is reached upon vacuum saturation as compared to the standard procedure. This increase can, however, be corrected for by means of a fixed correction factor. By combining the short test and a better selection of crucial parameters by means of a pH static leach test, a cost reduction relative to the complete NEN 7345 of at least a factor 30 can be achieved. By presenting the results of the short test in conjunction with the previously obtained NEN 7345 data (required by the Building Materials Decree), it will be easier to recognise potential deviations in behaviour, thus allowing corrective measures. Automation of the short test has been shown feasible and contributes to a better repeatability of the test. 25 refs.

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