Carbonation curing of concrete products has shown potentials for CO2 capture and storage with environmental, technical and economical benefits in global greenhouse gas mitigation exercise. The primary objective of this study is to investigate the effect of early age carbonation on mechanical performance and pH of concrete in an attempt to understand the process and promote large scale applications. / It was found that significant early strength was developed in cement and concrete through early age carbonation curing. The early strength could be maintained and improved due to subsequent hydration. Twenty-eight-day strength of carbonated cement and concrete was comparable to that of hydrated reference if subsequently cured in the air in a sealed bag, but was lower if subsequently cured in water. Treatment with either internal curing using lightweight aggregates or chemical admixture can effectively enhance late strength development in carbonated concrete. / For three typical cement-based products including cement paste compacts, concrete compacts and precast concrete, two-hour carbonation reduced pH value from 12.8 to 11.8 as the lowest and subsequent 28-day hydration could slightly increase pH by 2% as maximum. At any time pH of early age carbonated concrete was always higher than 11.5, a threshold value under which the corrosion of reinforcing steel is likely to occur in concrete. The high pH in early-age carbonated concrete was likely attributed to the fact that early age carbonation was an accelerated hydration process, which was totally different from weathering carbonation in which pH of concrete could be neutralized due to the decomposition of calcium hydroxide and calcium silicate hydrates gel. Therefore, early age carbonation technology is applicable not only to concrete products such as masonry units and paving stones, but possibly to precast concrete with steel reinforcement as well.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.100230 |
| Date | January 2007 |
| Creators | Lin, Xiaolu, 1975- |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Civil Engineering and Applied Mechanics.) |
| Rights | © Xiaolu Lin, 2007 |
| Relation | alephsysno: 002665934, proquestno: AAIMR38488, Theses scanned by UMI/ProQuest. |
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