Concrete strength tendency in the wall of cylindrical spun-cast concrete elements

The aim of the research was to characterize the concrete mixtures for spun-cast concrete and to determine the relationship between the compacting ratio and the manner of segregation. In the research 23 specimens of 9 different mixtures with low w/c ratio were tested. Investigated parameters included w/c, spinning speed, duration, and properties of the aggregate. The strength of the concrete in the outer; middle and inner region of the spun-cast element and of the vibrated cube was assessed by testing drilled cores. The optimal compacting energy caused by spinning was defined for different mixtures. Statistical regression functions depending on the parameters above were defined for the change of strength in the wall of the element.