New Insights Into the Effect of Calcium Hydroxide Precipitation on the Kinetics of Tricalcium Silicate Hydration

Bullard, Jeffrey W.; Flatt, Robert J.

doi:10.1111/j.1551-2916.2010.03656.x

Cited by 92 publications

(58 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Subsequently, during stage 2, commonly referred to as the induction period, the rate of hydration slows significantly, although the mechanism responsible for reduced hydration is still under debate. 51,52 Until recently, it has been widely hypothesized that a continuous, metastable passivation layer of hydration products forms on the C 3 S particle surfaces to inhibit further hydration. 52−55 More recently, it has been suggested that the induction period is associated predominantly with C 3 S dissolution from etch-pit steps, which is influenced by the degree of undersaturation of the solution with respect to C 3 S. 51 During the induction period, the solution becomes locally saturated with respect to C−S−H and the hydrates likely begin to precipitate onto particle surfaces, processes that are thought not to be directly responsible for the induction period itself.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Reactions and Surface Interactions of Saccharides in Cement Slurries

Smith

Roberts²,

Funkhouser

et al. 2012

Langmuir

View full text Add to dashboard Cite

Glucose, maltodextrin, and sucrose exhibit significant differences in their alkaline reaction properties and interactions in aluminate/silicate cement slurries that result in diverse hydration behaviors of cements. Using 1D solutionand solid-state 13 C nuclear magnetic resonance (NMR), the structures of these closely related saccharides are identified in aqueous cement slurry solutions and as adsorbed on inorganic oxide cement surfaces during the early stages of hydration. Solid-state 1D 29 Si and 2D 27 Al{ 1 H} and 13 C{ 1 H} NMR techniques, including the use of very high magnetic fields (18.8 T), allow the characterization of the hydrating silicate and aluminate surfaces, where interactions with adsorbed organic species influence hydration. These measurements establish the molecular features of the different saccharides that account for their different adsorption behaviors in hydrating cements. Specifically, sucrose is stable in alkaline cement slurries and exhibits selective adsorption at hydrating silicate surfaces but not at aluminate surfaces in cements. In contrast, glucose degrades into linear saccharinic or other carboxylic acids that adsorb relatively weakly and nonselectively on nonhydrated and hydrated cement particle surfaces. Maltodextrin exhibits intermediate reaction and sorption properties because of its oligomeric glucosidic structure that yields linear carboxylic acids and stable ring-containing degradation products that are similar to those of the glucose degradation products and sucrose, respectively. Such different reaction and adsorption behaviors provide insight into the factors responsible for the large differences in the rates at which aluminate and silicate cement species hydrate in the presence of otherwise closely related saccharides. ■ INTRODUCTIONSaccharide reactions and interactions at hydrating inorganic oxide surfaces significantly influence diverse surface chemistry processes that include carbonate formation in marine organisms, biosynthesis at aluminosilicate surfaces, biofuel production over heterogeneous catalysts, corrosion inhibition, and cement hydration. 1−7 The competitive adsorption of organic molecules and water at heterogeneous inorganic oxide surfaces influences reaction mechanisms, kinetics, molecular compositions and structures, and macroscopic material properties. Importantly, saccharide molecules are commonly used to alter the hydration processes and material properties of cements, such as the calcium aluminates and silicates that are widely used in synthetic structural materials. 8 In particular, the hydration kinetics of hydraulic aluminate/ silicate-based cements are critical to concrete construction and oilwell cementing, in which organic additives are often used to slow (inhibit) hydration processes or alter the rheological properties of cement−water mixtures, commonly referred to as cement "slurries". Despite their enormous technological importance, much remains to be known about the physicochemical interactions of the inorganic silicate or alumi...

show abstract

Section: ■ Results and Discussionmentioning

confidence: 99%

Reactions and Surface Interactions of Saccharides in Cement Slurries

Smith

Roberts²,

Funkhouser

et al. 2012

Langmuir

View full text Add to dashboard Cite

show abstract

“…Gartner et al [23] and Gartner and Jennings [39] have shown that the degree of instability of the metastable C-S-H layer (termed the initial shell in this paper) is related to its Ca/Si ratio, and that lower Ca/Si ratios lead to less instability of the C-S-H layer. Garrault and Nonat [40] and Bullard and Flatt [41], in studies on C 3 S hydration in dilute solution (liquid/solid = 50), pointed out that nucleation and growth of C-S-H nuclei at the initial period are faster at low lime (Ca(OH) 2 ) concentrations. It is difficult to extrapolate these findings to explain the hydration kinetics of the fly ash-cement pastes presented here.…”

Section: ) the Dilution Effectmentioning

confidence: 99%

“…In addition, the fly ash could supply significant amounts of silicate ions to the solution since the early age [41]. This effect also leads to a lower Ca/Si ratio of the solution and in the initial shell of fly ash-cement pastes [23,39], and results in a longer induction period for the hydration in fly ash-OPC pastes.…”

Section: Effect Of Fly Ash On the Reaction Coefficients Of Hydration mentioning

confidence: 99%

Effect of fly ash on the kinetics of Portland cement hydration at different curing temperatures

Narmluk

Nawa

2011

Cement and Concrete Research

185

View full text Add to dashboard Cite

“…Notably, Bullard has demonstrated that either the metastable barrier layer or hydroxylated surface hypothesis can adequately predict alite hydration rates, there being only minor differences in the predicted evolution of the solution chemistry [18]. But there were certain assumptions or implicit mechanistic functionality that were necessary to also make either mechanism work; establishing that such mechanisms are present is a challenge to be proven empirically.…”

Section: Ii2 Mechanismsmentioning

confidence: 99%

Paving the Way for a More Sustainable Concrete Infrastructure : A Vision for Developing a Comprehensive Description of Cement Hydration Kinetics

Biernacki¹,

Bullard²,

Constantiner³

et al. 2013

Self Cite

View full text Add to dashboard Cite

Pav i ng t he W ay f or a Mor e S u s t ai nabl e C onc r et e I nf r as t r u c t u r e A V i s i o n f o r D e v e l o p i n g a C o m p r e h e n s i v e D e s c r i p t i o n o f C e m e n t H y d r a t i o n K i n e t i c s National Institute of Standards and Technology Patrick D. Gallagher, Under Secretary of Commerce for Standards and Technology and DirectorCertain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose. iii iv National Institute of Standards and Technology ForewordConcrete is far and away the most abundantly used man--made material on the planet. As a construction material, it is unique in its capacity to be formed and finished into an almost unlimited variety of shapes, textures, and colors. It can be made on demand with portland cement and inexpensive local materials. With correct placement and use, concrete can have a service life of 50 years to more than 200 years. Improving the proper and efficient use of concrete and portland cement requires better understanding of the chemical process of hydration, and how that process can be characterized and modeled -both for pure portland systems and for those containing admixtures and supplemental cementitious materials such as fly ash, slag cement, and others. Having interactive computer models, based on sound experimental data, for the chemical and physical interaction of cementing compounds, molecules, and ions in the concrete pore--water solutions will help both to improve cement manufacture and to optimize sustainable concrete mixtures.Importantly, concrete has the lowest embodied CO 2 content of any major material used in construction, including glass, steel, and wood. But so much concrete is produced annually that it still accounts for about 8 of industrial CO 2 production. Therefore, reducing both the CO 2 contribution and embodied energy of concrete is a societal challenge that must be addressed to ensure a sustainable built environment and transportation infrastructure. One way to reduce concrete's CO 2 contribution is to lower its embodied CO 2 and energy content and even further, typically by both more efficient production of cement binder and partial replacement with supplementary cementitious materials or fine mineral fillers. This approach is already being used, but often with uncertainty in the way the binder will perform. Concrete is typically overdesigned by at least 10 % because of the inability to ensure the exact performance of the binder material. Therefore, the ability to accurately model cement hydration kinetics and predict and improve the performance of concrete as it hydrates could lead to a 1 % reduction in the mass of cement and concrete used each year and significantly reduc...

show abstract

New Insights Into the Effect of Calcium Hydroxide Precipitation on the Kinetics of Tricalcium Silicate Hydration

Cited by 92 publications

References 40 publications

Reactions and Surface Interactions of Saccharides in Cement Slurries

Reactions and Surface Interactions of Saccharides in Cement Slurries

Effect of fly ash on the kinetics of Portland cement hydration at different curing temperatures

Paving the Way for a More Sustainable Concrete Infrastructure : A Vision for Developing a Comprehensive Description of Cement Hydration Kinetics

Contact Info

Product

Resources

About