Toxicity of recycled concrete aggregates: Review on leaching tests

Abstract

The toxicity of building materials can be addressed in the areas of occupational and environmental 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 in the biosphere is examined. Several studies have been developed analysing the environmental impact of concrete production, considering a significant number of concrete constituents and different compositions, in order to find ways of minimizing it. On the other hand, only a few studies are focused on the toxicity area. Some of the traditional constituents of concrete may be potentially hazardous, presenting different levels of toxicity. 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. Thus, it is important to develop a greater number of concrete toxicity studies analysing different mixes and constituents, in order to identify several ways of minimizing the potential toxicity of this construction material. 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. Different procedures and results of the leaching tests of recycled concrete aggregates from previous studies will be presented and discussed in this paper.