The rheological and mechanical properties of self-compacting concrete with high calcium fly ash

The paper presents test results on the self-compacting concrete (SCC) modified with High Calcium Fly Ash (HCFA), SCC mixtures with cement modified by HCFA and high performance self-compacting concrete (HPSCC) modified by HCFA. HCFA was used as a replacement for a part of cement in the mixture (2 types of HCFA, also activated by grinding) or as an additive to cement. The research has shown the negative influence of raw calcium fly ash (without grinding) added to concrete mix on its rheological properties and workability. Activation of fly ash (by grinding) improves its properties, and becomes positive as an additive to concrete mixtures. The results include studies on samples belonging to classes of slump flow SF, classes of viscosity T₅₀₀, compressive strength and flexural strength tests. The concrete mixture was tested with a varying amount of HCFA (10-20-30%), as equivalent of cement.