Greening effect of concrete containing granulated blast-furnace slag composite cement: Is there an environmental impact?

Julien Couvidat (1, 2) , Cécile Diliberto (2) , Eric Meux , Laurent Izoret (3) , André Lecomte (2)

1 DEEP - Déchets Eaux Environnement Pollutions
2 IJL - Institut Jean Lamour
3 ATILH - Association Technique de l'Industrie des Liants Hydrauliques

The "greening effect" refers to hardened concrete containing Granulated Blast-Furnace Slag (GBFS) that displays a vivid blue-green color after removal of formwork. This temporary coloration effect, which fades within a few days to weeks, has raised concerns about its potential impact on the environment. Three types of leaching tests were conducted to assess different potential release scenarios: a sprinkling test, a static monolith tank test and a batch test on crushed samples. Slag content was linked to a higher release of sulfur anions in the leachates, in the form of sulfides, thiosulfates and sulfates. Most of these anions came from the GBFS, where sulfur is mainly in the form of sulfides with thiosulfates and sulfates as the main products of sulfide oxidation. Sulfate levels, however, were lower than threshold limit values for both inert waste and alternate materials reused in road construction. Moreover, no chromium, or other hazardous metals, were detected in the leachates.

Mots clés: foundation; fair faced concrete; sulfide; greening effect; blast-furnace slag; demolition

Domaines: Matériaux; Environnement et Société; Construction durable

Julien Couvidat, Cécile Diliberto, Eric Meux, Laurent Izoret, André Lecomte. Greening effect of concrete containing granulated blast-furnace slag composite cement: Is there an environmental impact?. Cement and Concrete Composites, 2020, 113, pp.103711. ⟨10.1016/j.cemconcomp.2020.103711⟩. ⟨hal-02894613⟩