Microstructure, thermal analysis and chloride penetration of self-compacting concrete under different conditions

This paper concerns the characterisation of the raw materials used in four formulations of self-compacting concrete (SCC) and the study of their fresh state, compressive strength, thermal analysis, transport properties and chloride penetration under immersion and tidal conditions. The control concrete corresponds to a concrete with class 40 MPa based on Portland cement and limestone filler. A second formulation involves the complete substitution of limestone filler by sand filler. In the two other formulations, 10% and 15% of metakaolin are substituted for cement. The results show that SCC with metakaolin exhibits higher resistance to chloride penetration at different states. A higher strength development is obtained when using sand filler. This is true up to 90 d of maturation; beyond this, the compressive strength increases for the control SCC. However, mixtures with metakaolin present compressive strength values close to or higher than the ones of the control mix at both early- and long-term ages. This research shows that the substitution of Portland cement by 15% metakaolin in SCC is affordable in all aspects.