Effect of autogenous shrinkage on microcracking and mass transport properties of concrete containing supplementary cementitious materials

It is well-known that supplementary cementitious materials (SCMs) and low water-to-binder (w/b) ratio increase autogenous shrinkage, but the impact on microcracking long-term transport properties less understood. This paper examines effect of induced by shrinkage concretes cured up to ~3.6 years. Variables include SCM type (9% SF, 70% GGBS), w/b (0.20–0.45), maximum-aggregate-size (MSA: 5–20 mm) reducing admixture (SRA). Oxygen diffusivity, permeability water sorptivity were correlated with microcracks characterised using laser scanning confocal microscopy 3D X-ray microtomography. Results show greater in mixes containing SCMs, large MSA. At same binder type, strong positive correlations are observed between increasing MSA, confirming negative shrinkage. SRA was effective these effects. The significance compared drying implications for durability discussed.