Rainwater can leach environmentally harmful substances from grouts and carry them into the environment.
Source: BAM
Prefabricated mixtures for grouts are used to fill joints between paving slabs. Different binders are used for this purpose. In addition to organically modified cement, the mixtures can also contain epoxy resins, polybutadiene, or polyurethane. It was not known whether these products differ in terms of possible environmental effects in outdoor applications. Eluates were prepared for test specimens from eight different grouts in accordance with European standard procedures for construction products and these were then investigated, also in accordance with European specifications for construction products, with regard to their ecotoxic effects on algae, daphnia, luminescent bacteria and fish eggs, and in genotoxicity tests. Particularly strong effects on the test organisms were observed for the eluates from the two epoxy resin-based products, while the effects of the eluates from two polybutadiene-based products were less pronounced, and minor to no ecotoxic effects occurred for two polyurethane- and two cement-based products. Substances occurring in the eluates were analyzed using chromatographic methods coupled with mass spectrometry.
A comparison with databases on ecotoxic properties indicates that the effects of the two epoxy resin-based products investigated were largely due to the release of amines and a butylphenol. The studies on grouts showed that ecotoxicity tests on eluates can be used to differentiate building products, from which unknown mixtures of substances can enter the environment via water contact, in terms of their environmentally hazardous properties. This helps users to select environmentally friendly products. Additional chemical analyses and a comparison with ecotoxicity data enables the identification of substances causing toxic effects. These findings can help manufacturers improve their products in terms of environmental compatibility.
The results will be used to further develop the assessment of the environmental properties of construction products on a European level and to certify environmentally friendly construction products with eco-labels. Future contributions of BAM can be exemplary investigations of building products and the identification of environmentally hazardous substances in eluates using modern analytical techniques.
Release of substances from joint grouts based on various binder types and their ecotoxic effects
Ute Schoknecht, Ute Kalbe, I. Heisterkamp, M. Kretzschmar, S. Gartiser, O. Happel, O. Ilvonen
published in Environmental Sciences Europe, Volume 34, Issue 1, Article number 111, 2022