Capillary Porosity Depercolation/Repercolation in Hydrating Cement Pastes Via Low‐Temperature Calorimetry Measurements and CEMHYD3D Modeling

Bentz, Dale P.

doi:10.1111/j.1551-2916.2006.01102.x

Cited by 37 publications

(25 citation statements)

References 15 publications

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“…A freezing scan can also be used to assess the percolation state of the capillary porosity, as in general, water in a larger pore will only freeze when a previously formed freezing front penetrates the smaller pore entryways. Thus, during an initial freezing scan, the presence or absence of a peak at a temperature in the range of -15 to -20°C is indicative of the percolation/ depercolation state of the capillary porosity in the specimen [21,23].…”

Section: Low Temperature Calorimetry-percolation/ Depercolation Of Camentioning

confidence: 98%

“…While setting is an example of a percolation process in hydrating cement pastes where the connectivity of the solid phases increases dramatically, there is an equally critical percolation process in which connectivity is gradually decreased and ultimately lost, namely the depercolation of the capillary porosity during hydration [19][20][21]. This depercolation results in a significant reduction in transport rates within the material, particularly the permeability [19].…”

Section: Low Temperature Calorimetry-percolation/ Depercolation Of Camentioning

confidence: 99%

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Critical observations for the evaluation of cement hydration models

Bentz

2010

Int J Adv Eng Sci Appl Math

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The development of computer models for cement hydration and microstructure development, with an explicit consideration of microstructure, has accelerated in the past 25 years, creating a need for a set of critical experimental observations that can be used in evaluating the model predictions. During this same time period, there have been rapid advances in experimental techniques for quantifying both the hydration rates and the produced microstructures. This paper utilizes several of these techniques to elaborate a preliminary set of experimental observations concerning the influence of water-to-cement ratio, cement particle size distribution, and curing conditions on hydration and microstructure development. Isothermal calorimetry provides a convenient measure of the ongoing hydration rates during the first 7 days of hydration, while low temperature calorimetry can be used to directly assess the percolation state of the capillary porosity and the quantity of freezable water in a hydrated cement paste. Conventional measurements of setting times, such as Vicat needle penetration, are related to the ongoing percolation transitions of the solids within the three-dimensional microstructure. Finally, since concretes in the field rarely experience saturated curing conditions, the influence of sealed curing on resultant degree of hydration and microstructure is examined. The presented data sets should provide a first step in performing a critical evaluation of existing and future computer models.

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Section: Low Temperature Calorimetry-percolation/ Depercolation Of Camentioning

confidence: 98%

Section: Low Temperature Calorimetry-percolation/ Depercolation Of Camentioning

confidence: 99%

Critical observations for the evaluation of cement hydration models

Bentz

2010

Int J Adv Eng Sci Appl Math

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“…The microstructure of cement paste is conducted using CEMHYD3D developed by Bentz (2006Bentz ( , 2005. In this digitized model, the initial 3D microstructure is first built on basis of real W/C, particle size distribution of cement, chemical composition, and spatial distribution of mineral phases.…”

Section: Numerical Modelingmentioning

confidence: 99%

Numerical Simulation of the Early Age Three-Dimensional Microstructure Development of Cement Pastes

Zhang¹,

Li²,

Sun³

2014

Proceedings of the 4th International Conference on the Durability of Concrete Structures

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The formation process of microstructure in cement pastes was first simulated with a numerical model CEMHYD3D. The influence of water-to-cement ratio and particles size on heat release and degree of hydration were then investigated. In addition, the mass of CH and C-S-H phases simulated have been verified by measuring values by thermogravimetry-differential scanning calorimetry (TG-DSC) and X-ray diffraction (XRD)-Rietveld analysis. The evolutions of solids phase percolation and capillary pores de-percolation were also identified by means of a three-dimensional (3D) numerical model. The results show that the simulated values are in good agreement with the available experimental data, indicating a good reliability of the CEMHYD3D model.

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“…Cuando no se produce el curado interno, el HAR puede sufrir en edades tempranas deformaciones y microfisuras importantes por todo el sistema (3). La densa microestructura del hormigón moderno produce rápidamente discontinuidad capilar en la red porosa inicial y, en consecuencia, impide el acceso del agua exterior al interior y con ello la saturación del volumen total (4). Es importante reducir este fenómeno y fomentar métodos para el curado interno.…”

Section: Introductionunclassified

Efecto de las condiciones de curado en las propiedades mecánicas de los morteros con partículas superabsorbentes

Esteves¹,

Paiva²,

Ferreira³

et al. 2010

Mater. construcc.

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RESUMENEste artículo presenta el efecto de las condiciones de curado sobre las propiedades mecánicas de los morteros a los que se han añadido polímeros superabsorbentes como agentes de curado interno. Los morteros se curaron a dos temperaturas, 20 y 40 °C, y a varios valores de la humedad relativa entre el 30 y el 95%. Se estudió asimismo dicho efecto en función de la relación agua/cemento. Se realizaron pruebas de resistencia a la compresión y a la tracción a distintas edades. Los resultados incluyen la evolución de la pérdida de masa y su relación tanto con las condiciones ambientales como con el comportamiento resistente de los morteros. El curado interno de éstos con polímeros superabsorbentes permitió el mantenimiento de sus propiedades mecánicas en condiciones de curado extremas.Palabras clave: polímeros superabsorbentes, morteros, curado, propiedades mecánicas. SUMMARYThis paper describes the effect of curing conditions on the mechanical properties of mortars containing superabsorbent polymers (SAP). Curing temperature and relative humidity were varied from 20 to 40 ºC and 30 to 95%, respectively, in mixes with different water/cement and cement/aggregate ratios. Tensile and compressive strength tests were performed at several ages. Weight loss over time was measured and related to curing conditions and strength. The addition of SAPs was found to effectively maintain cement-based mortar strength under extreme curing conditions. K Ke ey yw wo or rd ds s: : superabsorbent polymers, mortars, curing, mechanical properties.(

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Capillary Porosity Depercolation/Repercolation in Hydrating Cement Pastes Via Low‐Temperature Calorimetry Measurements and CEMHYD3D Modeling

Cited by 37 publications

References 15 publications

Critical observations for the evaluation of cement hydration models

Critical observations for the evaluation of cement hydration models

Numerical Simulation of the Early Age Three-Dimensional Microstructure Development of Cement Pastes

Efecto de las condiciones de curado en las propiedades mecánicas de los morteros con partículas superabsorbentes

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