| Abstract Scope |
In 2021, global sand and gravel extraction for concrete aggregates reached 46.2 Gt. These aggregates mainly come from extraction areas near rivers, causing significant environmental damage. To find alternatives, non-ferrous slags are being explored. These are rarely utilized, due to their undesirable by-elements, particularly the inevitable content of heavy metals. To address this, a slag originated from lead production, containing residual amounts of zinc, lead, and barium oxides, was modified to improve its ability to immobilize heavy metals. Four modified slags were created, varying in the ratio of key components CaO, MgO, SiO2, and Al2O3. Concrete samples were produced using these modified slags, replacing natural sand to different extents. Trials were conducted using nitric acid, caustic soda as well as distilled water, maintaining a constant pH level throughout the testing period. The slag concretes were analysed after curing periods of 7, 28, and 60 days. |