Determination by nanoindentation of elastic modulus and hardness of pure constituents of Portland cement clinker

Velez, Karine; Maximilien, Sandrine; Damidot, D.; Fantozzi, Gilbert; Sorrentino, Fransois

doi:10.1016/s0008-8846(00)00505-6

Cited by 417 publications

(196 citation statements)

References 5 publications

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“…Larger volumes will have a larger probability of containing weak spots and consequently will fail at lower loads (Van Mier 2012). Similar observations were made by Velez et al (2001), where nanoindentation measurements of the E modulus on pure Portland cement phases were compared to macroscopic scale measurement by the resonance frequencies technique. They observed consistency in results in microscopic and macroscopic scale measurements, where the porosity is the main influencing factor.…”

Section: Simulation Results and Discussionsupporting

confidence: 60%

Micromechanical Study of the Interface Properties in Concrete Repair Systems

Luković

Šavija

Dong

et al. 2014

ACT

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Micromechanical interface properties in a concrete repair system determine the performance and reliability of a repaired structure. In order to characterize these properties, nanoindentation technique was applied. Three different repair material mixtures, based on Portland cement or partial replacement of Portland cement with blast furnace slag, were tested. Hardness and elastic modulus values obtained from the nanoindentation were used directly as input for simulated direct tension test. This way, the fracture behaviour of original microstructure, "mimicked" by Delft lattice model, is analysed. Backscattered electron (BSE) image analysis is utilized to estimate the average size of the interface zone which is distinguished as locally more porous area. This, together with simulation results, is further used for calculation of the interface stiffness. Simulation results enable prediction and better insight into fracture propagation and micromechanical response of the tested zone. They also indicate the ratio between interface and bulk material fracture properties when different types of repair materials are used. Load displacement diagrams of interface, old and new material can serve as an input for numerical modelling and understanding of fracture behaviour of the repair systems at the higher scale. Potentially, this approach may develop as a tool for verifying and engineering interface properties such that desired performance of the repaired structure is achieved.

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Section: Simulation Results and Discussionsupporting

confidence: 60%

Micromechanical Study of the Interface Properties in Concrete Repair Systems

Luković

Šavija

Dong

et al. 2014

ACT

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“…While it is generally agreed that creep of cement paste originates in calcium silicate hydrate (C-S-H) (Ulm et al 1999;Velez et al 2001;Bernard et al 2003;Vandamme 2008), homogeneous C-S-H identical to the C-S-H in a hydrating cement paste seems impossible to prepare at scales suitable for mechanical testing. The identification of C-S-H properties therefore comes from one of two approaches: 1.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Modeling of Early-Age Creep in Hydrating Cement Paste

Bishnoi

Scrivener

2016

J. Eng. Mech.

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This paper presents a new approach to model the creep behavior of cement paste at early ages. The creep behavior is simulated by applying a time-varying generalized Maxwell model on the individual elements of a finite-element mesh of a simulated three-dimensional microstructure and compared with results in the literature. All mechanical properties of the constituent phases are taken from literature and Maxwell chain parameters are obtained by fitting the intrinsic creep of calcium silicate hydrate (C-S-H). A reasonable agreement between the simulations and the experimental results are obtained by assuming a constant C-S-H density of 2.0 g=cm 3 . It was found that better agreements could be obtained at low degree of hydrations, by assuming a loosely packed C-S-H growing in the microstructure. It was also found that the short-term creep characteristics of C-S-H from nanoindentation can be used to reproduce macroscopic creep at least over a few days. The results show how numerical models can be used to upscale phase characteristics to macroscopic properties of composites.

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“…and with resonance frequency measurements of Young's moduli E up to 160 GPa, 50 which correspond to Bulk moduli up to 127 GPa according to the relationship K = E/[3(1 − 2ν)] for isotropic elastic solids (Table 4). 66 Computed uniaxial stress-strain curves along the three principal axes x, y, and z converge to the same Young's modulus E of 134 ± 5 GPa within small deviations (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Measurements indicate Young's moduli in the range 135 to 145 GPa at low stress. 26,50 The capability of quantitative predictions of mechanical properties can also be applied to heterogeneous mineral structures in dry and hydrated cements using existing parameters for other cement phases. 10 …”

Section: Methodsmentioning

confidence: 99%

A force field for tricalcium aluminate to characterize surface properties, initial hydration, and organically modified interfaces in atomic resolution

et al. 2014

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Tricalcium aluminate (C 3 A) is a major phase of Portland cement clinker and some dental root filling cements. An accurate all-atom force field is introduced to examine structural, surface, and hydration properties as well as organic interfaces to overcome challenges using current laboratory instrumentation. Molecular dynamics simulation demonstrates excellent agreement of computed structural, thermal, mechanical, and surface properties with available experimental data. The parameters are integrated into multiple potential energy expressions, including the PCFF, CVFF, CHARMM, AMBER, OPLS, and INTERFACE force fields. This choice enables the simulation of a wide range of inorganic-organic interfaces at the 1 to 100 nm scale at a million times lower computational cost than DFT methods. Molecular models of dry and partially hydrated surfaces are introduced to examine cleavage, agglomeration, and the role of adsorbed organic molecules. Cleavage of crystalline tricalcium aluminate requires approximately 1300 mJ m −2 and superficial hydration introduces an amorphous calcium hydroxide surface layer that reduces the agglomeration energy from approximately 850 mJ m −2 to 500 mJ m −2 , as well as to lower values upon surface displacement. The adsorption of several alcohols and amines was examined to understand their role as grinding aids and as hydration modifiers in cement. The molecules mitigate local electric fields through complexation of calcium ions, hydrogen bonds, and introduction of hydrophobicity upon binding. Molecularly thin layers of about 0.5 nm thickness reduce agglomeration energies to between 100 and 30 mJ m −2 . Molecule-specific trends were found to be similar for tricalcium aluminate and tricalcium silicate. The models allow quantitative predictions and are a starting point to provide fundamental understanding of the role of C 3 A and organic additives in cement. Extensions to impure phases and advanced hydration stages are feasible.

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Determination by nanoindentation of elastic modulus and hardness of pure constituents of Portland cement clinker

Cited by 417 publications

References 5 publications

Micromechanical Study of the Interface Properties in Concrete Repair Systems

Micromechanical Study of the Interface Properties in Concrete Repair Systems

Microstructural Modeling of Early-Age Creep in Hydrating Cement Paste

A force field for tricalcium aluminate to characterize surface properties, initial hydration, and organically modified interfaces in atomic resolution

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