Effect of Novel Organo-Mineral Phases on Cement Hydration and Concrete Properties L. Raki, J. J. Beaudoin and G. Chan Institute for Research in Construction, National Research Council Canada International Summit on Cement Hydration Kinetics and Modeling Laval University , Quebec, July 27-29, 2009
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Effect of Novel Organo-Mineral Phases on Cement Hydration and Concrete Properties
L. Raki, J. J. Beaudoin and G. ChanInstitute for Research in Construction, National Research Council Canada
International Summit on Cement Hydration Kinetics and Modeling
Laval University , Quebec, July 27-29, 2009
Outline
• Background
• Controlled release (CR) technology
• Proof of CR concept in concrete
• Application of CR approach in cement/concrete
• Concluding remarks
Depending on the improved property, admixtures can be classified in
different categories:
• Set modifiers: retarders or accelerators
• Water reducers
• Air entraining agents
• Corrosion inhibitors
• Shrinkage reducers
• Pumping aids
• Anti-bleeding, anti-segregation, or anti-washout agents
• Anti-freezing agents
• Defoamers….etc
• Superplasticizers
Sulfonate-based:
• Polymelamine sulfonates (PMF)
• Poly-β-naphthalene sulfonates (PNF)
Carboxylate-based:
• Polycarboxylates
• Polyacrylates
Concrete Admixtures
Rationale for Use of CR Technology
Slump loss:
CR can minimize workability loss and extend the practical range of on-site delivery
Nature of admixtures interactions with cement hydrates influences hardened properties of concrete:
CR can mitigate the effects of preferential adsorption of superplasticizers by aluminate phases
Our Challenge
Develop new technologies and innovative solutions for delivery of
admixtures in cement systems
Use of nanotechnology approach
Synthesis of novel cement-based materials-CR of chemicals
Controlled Release: A Multidisciplinary Concept
• Pharmaceutical: delivery carrier for drugs
• Medicine: gene reservoirs
• Agriculture: plant growth regulators
• Food industry: flavor protection
• Environment: waste treatment
• Construction: cement-additive for time controlled delivery of superplasticizers, corrosion inhibitors and other functional admixtures
“Encapsulation”
• C. M. Dry:
− coated hollow polypropylene fibers used to disperse a corrosion inhibitor (calcium nitrate); Cem. Concr. Res.
• B. R. Reddy et al. : Oil well treating fluids encapsulated in porous solid materials eg. Metal oxides containing accelerators, retarders, dispersants. US. Patent 6, 209, 646, 2001
Relevant Literature in Cement Systems
Relevant Literature in Cement Systems
“In situ chemical reactions”
K. Hambae et al. : addition of substances which hydrolyze under alkaline conditions (pH=12.5) to form cement dispersing agents. EU Patent EP0402319, 1994; US. Patent 5350450, 1994.
“Intercalation/de-intercalation”
H. Tatematsu et al. : inorganic and organic cation and anion xchangers eg. Calcium substituted zeolite and hydrocalumite. Exchange of alkali and chloride ion inhibit alkali-aggregate reaction and corrosion of rebar. US. Patent 5,435, 848, 1995.
L. Raki et al.: de-intercalation of layered double hydroxides to control loss of workability in cement-based materials, US. Patent Applic. 0022916 A1, 2007
Chemical Structure of Layered (L) Double (D) Hydroxides(Hs)