Utilization of Limestone Powder and Metakaolin as Mineral Fillers in High-Performance Self-Compacting Concrete

Abstract

In the present work, limestone powder (LSP) and calcined clay (metakaolin, MK) were used as mineral fillers in two different mixtures of high-performance self-compacting concrete (SCC). In the first mixture, LSP was used alone as the mineral filler, whereas in the second one, the mineral filler consisted of the blend of LSP and MK. For both SCC mixtures, dune sand was used as fine aggregate and crushed limestone particles were used as coarse aggregate. Both SCC mixtures were prepared using a total powder content of 500 kg/m3 (400 kg/m3 Portland cement and 100 kg/m3 mineral filler), a water/powder ratio of 0.3, and a fine/total aggregate ratio of 0.4. Dosages of superplasticizer and stabilizer were optimized through trials satisfying the self-compactability requirements. Performance of the SCC mixtures was evaluated in terms of selected mechanical properties, durability characteristics, and resistance against reinforcement corrosion that included compressive and splitting tensile strengths, modulus of elasticity, water penetration depth, rapid chloride permeability, electrical resistivity, and reinforcement corrosion monitoring. Both SCC mixtures achieved 28-day compressive strength (above 60 MPa), splitting tensile strength (above 5 MPa), and modulus of elasticity (above 40 GPa), low water permeability, very low chloride permeability, and negligible corrosion risk, indicating suitability of using LSP and MK as mineral filler for producing high-performance SCC. The self-compactability and mechanical properties of the mixture with the blend of LSP and MK were slightly better than the mixture with LSP alone; however, both mixtures showed the same durability characteristics and resistance against reinforcement corrosion.