Temperature effects in reinforced concrete chimneys and the prospects of steel fibre shotcrete application for the reinforcement of chimney shafts
A.P. Krichevsky, Brizhaty, Korsun & S.A. Krichevsky
CICIND REPORT Vol. 12, No. 1, 1996
Order No: CR-042
The paper discusses the effects on concrete of heating one side, alternately heating and cooling (to -50oC in Ukraine & Russia) the other side and wetting/drying both sides. These involve the formation of micro-cracks, which weaken the concrete section, and experimental work confirms a long-term degradation of concrete strength in these conditions. The effects on concrete strength of adding varying concentrations of straight and of wavy steel fibres are described in detail. While the wavy fibres appear to be more efficient, they give rise to mixing problems in relatively high concentrations (2% - 4%), so a "Cocktail" is described comprising a small concentration of wavy fibres mixed with a greater concentration of straight fibres. A mixture of 1% wavy and 3% straight fibres increases flexural strength by about 250%.