Evaluation of chromium leaching in concrete by immersion and irrigation methods

ABSTRACT

The search for materials in eco-efficient civil construction can be carried out by adding or replacing raw materials with waste generated in other industrial sectors. Many of these residues are classified as hazardous, and the inertization of compounds that confer dangerousness can be performed through stabilization by solidification (S/S) that causes the encapsulation and chemical fixation of toxic substances. However, in Brazil there is no regulated standard or even a technical recommendation, which is specific for S/S products used as building components. In this context, the present study aimed to evaluate the leaching of chromium in Portland cement concrete matrix by immersion and irrigation methods, with a view to the use of these methods in the environmental assessment of materials and components of civil construction. For this, specimens of 25x200x400 mm were made with and without the addition of 2% Cr₂O₃ (chromium oxide) in relation to the Portland cement mass, which were subjected to immersion and irrigation leaching tests. The results obtained allowed to verify the encapsulation of chromium in the concrete and that the leaching tests proposed in concrete monoliths, during the use phase, proved to be applicable in 28 days.

Keywords
Environmental assessment; Stabilization by solidification; Leaching; Chromium; Concrete; Portland cement