Publication: Evaluation of drying shrinkage and residual stresses of a high strength concrete using restrained ring test
Abstract
Volume changes in concrete start at early ages (plastic shrinkage) and continue after hardening as a result of drying shrinkage. When restrained, these volume changes cause cracking because of the poor tensile strength of concrete. The present investigation was aimed at mitigating drying shrinkage cracks in high strength silica fume concrete by the addition of a combination of metallic (steel) and non-metallic fibres (polypropylene, polyester and glass). The relative performance of the plain and fibre reinforced concrete mixtures was quantified in terms of the residual stresses generated upon drying. Residual stresses were calculated from the measured strain in a steel ring using a restrained ring test set-up. The experimental results showed that drying shrinkage cracking occurred earlier in the plain concrete specimen compared to fibre reinforced concrete specimens. The hybrid combinations of steel and non-metallic fibre performed better than the steel fibre reinforced concrete, possibly due to the increased fibre availability resulting from the addition of non-metattic fibres (which have lower specific gravity and higher aspect ratios compared to steel fibres). Among the three hybrid fibre combinations, the steel-polyester combination showed the lowest drying shrinkage cracking potential.
Description
Keywords
Drying shrinkage, Hybrid fibre concretes, Residual stresses, Restrained ring