Influence of accelerated carbonation curing on the properties of self-compacting concrete mixtures containing different mineral fillers

This paper presents a study on the effects of accelerated carbonation curing (ACC) on performance of self-compacting concrete (SCC) mixtures prepared using limestone powder (LSP) alone and blend of limestone powder and silica fume (SF) as mineral fillers. Specimens cast using both SCC mixtures were subjected to ACC that consisted of exposing specimens to CO2 for 10 hours under a constant pressure of 414 kPa. ACC-treated specimens were tested for evaluating effects of ACC on properties of SCC mixtures in terms of CO2 uptake, mechanical and durability properties, morphology, and mineralogy. Test results indicate that the ACC-treatment substantially enhanced the properties of both SCC mixtures. Strength of ACC-treated concrete specimens can be improved further by exposing them to air for a period of first 7 days of the ACC-treatment. ACC-treatment of LSP-SF-C was more effective than that for LSP-C. Properties of ACC-treated SCC mixtures were comparable with that of the same mixtures subjected to moist-curing for 7 days except drying shrinkage, which was higher for ACC-treated specimens than the moist-cured specimens. However, shrinkage of ACC-treated specimens after 7 days was within the permissible limit in case of LSP-C whereas 7-day shrinkage for LSP-SF-C exceeded the permissible limit of 500 mu m.