Physico-mechanical properties of phosphogypsum and black steel slag as aggregate for bentonite-lime based materials

This study aim to valorizing phosphogypsum (PG) and steel slag (Sc) in geotechnical applications by incorporating them in bentonite (B) stabilized by lime (L). Mineralogical (XRD), spectroscopic (IR-FTIR), geotechnical (Atterberg limits) analyzes were carried out on the raw material. Resistance to axial compression (UCS) was performed on cylindrical specimens prepared for mixtures B-L, B-L-PG, B-L-PG-Sc and cured for 3, 7, 15 and 28 days. The results obtained revealed that the mechanical strength increases with the addition of PG, and reaches its maximum value for a water content equal to 46%. Slag improves the strength of the B-L-PG mixture. The pH and the electrical conductivity of the solutions containing in porosity of the various mixtures decrease over time. The observed decrease is greatest for B-L-PG and B-L-PG-Sc mixtures due to pozzolanic reactions.