Early development of properties in a cement paste: A numerical and experimental study

Princigallo, Antonio; Lura, Pietro; Breugel, K. van; Levita, G.

doi:10.1016/s0008-8846(03)00002-4

Cited by 65 publications

(24 citation statements)

References 9 publications

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“…2 Salem and Ragai 10,11 showed that the addition of silica fume leads to an increase in the initial conductivity values as well as a shift of the conductivity peak to longer times of hydration and that the hystersis area increases with increasing silica fume content, indicating a notable structure breakdown. It is worth mentioning that Princigallo et al 8 found a remarkable similarity between autogenous shrinkage and electrical conductivity, which confirms that the pore dynamics is the common origin of the mechanical and electrical behaviours of cement. As stated before, the relative electrical conductivity is necessary to evaluate the permeability of cement paste.…”

Section: Introductionmentioning

confidence: 63%

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Prediction of relative electrical conductivity of saturated cement paste

Zheng¹,

Zhou²

2008

Magazine of Concrete Research

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Owing to its importance both in assessing the microstructural development and in computing the ionic diffusivity and permeability, it is of great practical significance to determine the relative electrical conductivity of saturated cement paste. This paper presents an analytical solution for the relative electrical conductivity of saturated cement paste. By modelling saturated cement paste as a two-phase composite material, consisting of capillary pores, and hydrated products and unhydrated cement grains, an analytical solution is derived for the relative electrical conductivity of saturated cement paste based on the general effective medium theory. Two parameters involved in the analytical solution are then determined by experimental calibration. After verifying the analytical solution with two sets of experimental results obtained from the literature, the effects of the water/cement (w/c) ratio and the degree of hydration on the relative electrical conductivity of saturated cement paste are evaluated in a quantitative manner. It is found that the relative electrical conductivity of saturated cement paste decreases with the decrease of the w/c ratio and/or with the increase of the degree of hydration. The paper concludes that the analytical solution presented can predict the relative electrical conductivity of saturated cement paste with reasonable accuracy. Notation aintermediate coefficient H(V 1 ÀV 1c ) Heaviside step function in terms of V 1 and V 1,c h 1 , h 2 coefficients between zero and one m percolation exponent in terms of n n parameter R cp relative electrical conductivity of saturated cement paste to pore solution t parameter larger than or equal to zero V 1 , V 2 , volume fractions of phase 1 (capillary pores) and phase 2 (hydrated products and unhydrated cement particles) V 1,c critical volume fraction of phase 1 V cap volume fraction of capillary pores V hyd volume fraction of hydrated products V unhyd volume fraction of unhydrated cement grains w/c water/cement ratio AE degree of hydration ó 1 , ó 2 electrical conductivities of phases 1 and 2 ó s , ó cp , ó 0 electrical conductivities of pore solution, saturated cement paste and hypothetical homogeneous medium

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Section: Introductionmentioning

confidence: 63%

“…8 The sensor consists of two cylindrical rods and is controlled by a microchip that allows continuous measuring. The cement paste is sealed and its temperature is kept at a given value by means of a cooling system.…”

Section: Introductionmentioning

confidence: 99%

Prediction of relative electrical conductivity of saturated cement paste

Zheng¹,

Zhou²

2008

Magazine of Concrete Research

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“…136, JANUARY 2014 Transactions of the ASME macroscale mechanical behavior of cementitious materials; the properties need to be determined at the microlength scales. In recent years there has been an intensive research activity devoted to describing the cementitious materials by computational means [10,[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. At the microlevel the representative volume approach is widely used due to the flexibility and applicability of this method to various physical processes at the microscale, such as chemical kinetics, electrical and thermal conductivity, as well as linear and nonlinear elastic properties.…”

Section: Representative Volume Elementmentioning

confidence: 99%

Representative Volume Element Based Modeling of Cementitious Materials

Shahzamanian

Tadepalli

Rajendran

et al. 2013

Journal of Engineering Materials and Technology

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The current work focuses on evaluation of the effective elastic properties of cementitious materials through a voxel based finite element analysis (FEA) approach. Voxels are generated for a heterogeneous cementitious material (type-I cement) consisting of typical volume fractions of various constituent phases from digital microstructures. The microstructure is modeled as a microscale representative volume element (RVE) in ABAQUS V R to generate cubes several tens of microns in dimension and subjected to various prescribed deformation modes to generate the effective elastic tensor of the material. The RVE-calculated elastic properties such as moduli and Poisson's ratio are validated through an asymptotic expansion homogenization (AEH) and compared with rule of mixtures. Both periodic (PBC) and kinematic boundary conditions (KBC) are investigated to determine if the elastic properties are invariant due to boundary conditions. In addition, the method of "Windowing" was used to assess the randomness of the constituents and to validate how the isotropic elastic properties were determined. The average elastic properties obtained from the displacement based FEA of various locally anisotropic microsize cubes extracted from an RVE of size 100 Â 100 Â 100 lm showed that the overall RVE response was fully isotropic. The effects of domain size, degree of hydration (DOH), kinematic and periodic boundary conditions, domain sampling techniques, local anisotropy, particle size distribution (PSD), and random microstructure on elastic properties are studied.

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“…As would be expected, the lower w/c mixtures require less time to achieve percolation (set), due to their reduced initial particle spacing [34]. Several recent studies have demonstrated correlation between experimental measurements of setting, such as ultrasonics and needle penetration, and various model-based measurements of solids percolation [13,14,16,17]. Thus, it is important for cement hydration and microstructural models first to provide a measure of solids percolation and then to duplicate these commonly observed influences of w/c on setting.…”

Section: Critical Observationsmentioning

confidence: 94%

“…While isothermal calorimetry monitors the rate of chemical reactions in a cementitious system, the actual hardening of the cement paste microstructure is a physical process that depends on building ''bridges'' between the reacting cement particles [12][13][14][15][16][17]. This percolation of a ''solid'' backbone across the 3-D volume of cement paste is typically assessed using a penetration test such as that described in the ASTM C 191 standard test methods for time of setting of hydraulic cement by Vicat needle [10].…”

Section: Vicat Needle Penetration-percolation Of Solidsmentioning

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 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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Early development of properties in a cement paste: A numerical and experimental study

Cited by 65 publications

References 9 publications

Prediction of relative electrical conductivity of saturated cement paste

Prediction of relative electrical conductivity of saturated cement paste

Representative Volume Element Based Modeling of Cementitious Materials

Critical observations for the evaluation of cement hydration models

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