Fresh and hardened properties of self-compacting concretes produced with diabase and gneiss quarry by-product powders as alternative fillers

Abstract

This work investigated the use of diabase (D) and gneiss (G) quarry powders as alternatives to limestone filler (L) for self-compacting concrete (SCC) production. For this, SCCs with the different quarry powders, each one in three different particle size distributions, were produced. The shape and texture of the particles were evaluated through SEM image analysis. The fresh state properties of the SCCs were evaluated by the workability tests slump flow, V-Funnel, J-ring and VSI, and by rheometry. The cement hydration was evaluated in pastes by isothermal calorimetry up to 40 h, and thermogravimetric analysis (TGA) at 28 days. Finally, the compressive and splitting tensile strength, cement index and modulus of elasticity of the SCCs were determined at 28 days. The results showed that the SCCs containing D and G had fresh state properties equivalent to those containing L or only Portland cement, with slump flow of 700 ± 50 mm, V-Funnel time from 4.3 to 8.0 s, and VSI of 0 or 1. The isothermal calorimetry and TGA indicated a further hydration degree in the pastes containing D and G in comparison to L, reaching heat release peaks and hydrates contents (after 28 days) up to 25% and 35% higher, respectively. The SCCs containing D and G reached compressive strength, splitting tensile strength and modulus of elasticity respectively of 60.5 MPa, 6.1 MPa and 39.9 GPa. These values were up to 10%, 16% and 16% higher than those of the L-containing SCCs, respectively. Finally, the use of the quarry powders decreased the cement consumptions to achieve 1 MPa by up to 35% in comparison to the reference SCC (from 9.8 kg/m3.MPa for the reference to 6.3 kg/m3.MPa for D2-SCC). Overall, diabase and gneiss powders can be used as alternative fillers for the production of SCCs.