Concrete strength tendency in the wall of cylindrical spun-cast concrete elements
Periodica polytechnica. Civil engineering
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
... e 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. Notation c Consistence determined by flow table tests [cm] f cm,cyl Mean value of compressive strength of standard 150×300 mm cylinder [MPa] f cm,core Mean value of standard (150*300 mm) cylinder compressive strength of 60 mm diameter drilled core [MPa] f cm,out Modified standard cylinder compressive strength of drilled core from outer region [MPa] f cm,in Modified standard cylinder compressive strength of drilled core from inner region [MPa] P e Paste excess [dm 3 /m 3 ] R Outer radius of specimen [mm] T Total time of spinning [sec] Concrete strength tendency in the wall of cylindrical spun-cast concrete elements 23 2010 54 1 Per. Pol. Civil Eng.