Rheology and mechanical characteristics of self-compacting concrete mixtures containing metakaolin

• Workability is affected by the introduction of mk as a replacement material of c or lp.
• Higher mk/c or mk/lp levels lead to linearly higher compressive strengths.
• Regardless of the replaced material (c or lp), fcc is similarly affected by mk.
• Higher mk/c or mk/lp levels lead to higher tensile splitting strengths.
• Code curves overestimate the tensile splitting strength for a given compressive strength.

Metakaolin is a supplementary cementing material (SCM), which has been recently used in Self-Compacting Concrete (SCC). This study investigates the effect of replacement of cement or limestone powder by metakaolin, on the rheology and the mechanical characteristics of the concrete mixtures. It has been found that the rheological behaviour of SCC is affected by the incorporation of metakaolin. Yet, this effect is not always traceable in the assigned rheological classes. The compressive strength is significantly enhanced and a similarly increasing trend is observed for higher replacement levels, regardless of the replaced material. A lower but still considerable improvement of the tensile strength is also evident. Finally, code or literature curves for NVC tend to overestimate the tensile strength for SCC.