Toxicity of Recycled Concrete Aggregates: Review on Leaching Tests

Margarida Braga Maia1, *, Jorge De Brito1, Isabel M. Martins2, Jose D. Silvestre1
1 CERIS, Department of Civil Engineering, Architecture and Georresources, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-011 Lisboa, Portugal
2 Department of Materials, Laboratório Nacional de Engenharia Civil (LNEC) Av. do Brasil 101, 1700-066 Lisboa, Portugal

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© 2018 Maia et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this authors at the CERIS, Department of Civil Engineering, Architecture and Georresources, Instituto Superior Técnico, University of Lisbon Av. Rovisco Pais, 1049-011 Lisboa, Portugal; Tel: +351218418118; E-mail:;



The toxicity of building materials can be addressed in the areas of occupational and environ-mental toxicology. In the first case, the harmful effects to workers caused by exposure to a specific substance during building materials production are analysed. In the latter case, the toxic effects of that substance on living organisms is examined.

Several studies analysed the environmental impact of concrete production, considering a significant number of concrete constituents and compositions, in order to find ways of minimizing it. However, some of the traditional constituents of concrete may be potentially hazardous, presenting different levels of toxicity, but only a few studies are focused on this area. Still, and in order to reduce the potential environmental impact, studies have already started on the incorporation of alternative raw materials, which may affect concrete toxicity.

It is important to develop more concrete toxicity studies analysing different mixes and constituents, in order to identify several ways of minimizing the potential toxicity of this construction material.


Different procedures and results of the leaching tests of Recycled Concrete Aggregates (RCA) from previous studies will be presented and discussed in this paper.


The ecotoxicological characterization of materials is based on the analysis of the eluates resulting from leaching tests. There are several researches that apply different experimental leaching procedures according to existing standards and others with some variations in the standard test conditions: particle size, duration of the test, among others.

Results and conclusion:

The main characteristics of RCA that affect the results of the leaching tests will be identified.

Keywords: Leaching, Recycled concrete aggregates, Toxicity, Eluate, Construction materials, Sustainability.