Toxicity of cement-based materials

Abstract

Clinker production represents a high percentage of global CO2 emissions and a significant decrease by 2030 is mandatory. Therefore, there is a permanent search for innovative and sustainable cement-based construction materials (CBM) around the world. The increased development and demand of sustainable construction solutions pushed the incorporation of nontraditional raw materials in CBM mixes. Due to the insufficient knowledge on the use of these components, it is fundamental to perform studies to assess their toxicological effects on the relevant environmental compartments. Some studies are found in the literature that analysed the environmental impacts of new CBM but there are not many that include a toxicity analysis. The procedures followed in the latter are varied since there were no specific recommendations to analyse construction materials until 2017, and the results were obtained following different standards or directives. Therefore, the direct comparison of the results of these studies is generally not possible. In that year, a guidance on the use of ecotoxicity tests on construction products was published - technical report CEN/TR 17105:2017 (Construction products - Assessment of release of dangerous substances). Nevertheless, the process to evaluate the potential toxicity of construction materials is complex, but fundamental. In fact, there is no direct correlation between existing metals' concentration in one product and leached metals' concentration, which makes it difficult to know the toxicity level. The aim of this paper is to review and present available CBM toxicity information, including standards, databases or labels. The tools that already exist to support the evaluation of the toxicity risks of CBM will also be analysed. Based on this, an approach for the toxicity evaluation of CBM is proposed in order to provide researchers with real-time support for the development of sustainable CBM with reduced risks associated with toxicity.