Mechanical threshold of cementitious materials at early age

Torrenti, Jean Michel; Benboudjema, Farid

doi:10.1007/bf02479294

Cited by 42 publications

(29 citation statements)

References 9 publications

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“…, are clearly preferable over unloading experiments. However, indirect determination of hydration degree thresholds was carried out by Torrenti and Benboudjema who (i) approximated straight line fits to early‐age strength data of Taplin and (ii) performed extrapolations down to vanishing strength values for the estimation of hydration degree thresholds. Given that the here‐measured stiffness evolutions are in very good approximation linear functions of hydration degree, in the investigated regime of hydration degrees ranging from 40 to 60%, we implement the same approach in the present context of early‐age stiffness data.…”

Section: Discussionmentioning

confidence: 99%

Unloading‐Based Stiffness Characterisation of Cement Pastes During the Second, Third and Fourth Day After Production

Karte

Hlobil

Reihsner

et al. 2015

Strain

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The stiffness evolution of binder 'cement paste' is triggering the stiffness of concrete. In the engineering practice, concrete formworks are typically removed 24 h after production. This underlines that knowledge on mechanical properties of cementitious materials during the second, third and fourth day after production is of high relevance for the ongoing construction process. This provides the motivation to perform early-age stiffness characterisation on hydrating cement pastes, by means of the following three test methods. Unloading modulus is determined using a novel setup for non-destructive uniaxial compression testing including overdetermined deformation measurements. Dynamic Young's moduli are obtained from ultrasonics experiments. Isothermal differential calorimetry allows for linking the observed temporal evolution of early-age stiffness to the hydration degree of cement. Pastes with three different compositions are investigated, defined in terms of the initial water-to-cement mass ratio w/c and the initial water-to-solid (binder) mass ratio w/s. Pure cement pastes exhibit w/c = w/s = 0.50 and w/c = w/s = 0.42, respectively. A fly ashblended cement paste refers to a cement mass replacement level of 16%, and this is related to w/c = 0.50 and w/s = 0.42. Both unloading moduli and dynamic Young's moduli of all three materials increase practically linearly with increasing hydration degree, in the investigated regime of hydration degrees ranging from 40 to 60%. Fly ash does not contribute significantly to the early-age hydration of the material, i. e. it represents a quasi-inert part of the material's microstructure, exhibiting a significant stiffening effect.

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Section: Discussionmentioning

confidence: 99%

Unloading‐Based Stiffness Characterisation of Cement Pastes During the Second, Third and Fourth Day After Production

Karte

Hlobil

Reihsner

et al. 2015

Strain

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“…PC H showed initial setting after 1.7 hours while PC L set only after 3.3 hours. In this sense, setting time depends on the initial particle size (which is similar for the two cements) and the composition of the binders (32,33). PC H had some higher content of alite and aluminate than PC L consistent with the faster setting of PC H .…”

Section: Ternary Blends Contribution To the Early Cement Hydrationmentioning

confidence: 96%

Influence of the synergy between mineral additions and Portland cement in the physical-mechanical properties of ternary binders

et al. 2016

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ABSTRACT:The paper deals with the synergistic effect of mineral additions on the physical-mechanical performance of ternary blends prepared with different Portland cements (PC). The effect in setting and heat flow release is also analyzed. The mineral additions used are blast furnace slag (BFS), fly ash (FA) and limestone filler (LF). PCs with different C 3 A and alkali content have been tested to study the synergy in ternary blends. Ternary binders with PC low in C 3 A and alkali content achieve similar mechanical strength gain as plain PC and refinement of pore size distribution from early hydration ages due to the acceleration of PC hydration induced by the mineral additions. In contrast, ternary binders with PC higher in C 3 A and alkali content have a delayed in mechanical strength at early hydration ages, but significantly higher at long hydration times. RESUMEN: Prestaciones físico-mecánicas en cementos ternarios dependiendo de la sinergia entre las adiciones minerales y el cemento Portland.El artículo aborda la interacción sinérgica de las adiciones minerales en el rendimiento físico-mecánico de mezclas ternarias preparadas con dos tipos de cemento Portland (PC). Se analiza desde las edades tempranas la contribución en los tiempos de fraguado y en el flujo de calor liberado. Las adiciones minerales usadas son escoria de alto horno, ceniza volante y filler calizo. Los PC utilizados se han seleccionado en base al contenido en C 3 A y álcalis. Mezclas formuladas con PC de bajo contenido en C 3 A y álcalis mantienen desde el inicio una ganancia similar en las prestaciones mecánicas y un refinamiento en el tamaño de poro atribuido a la aceleración inducida por las adiciones minerales en la hidratación inicial del PC. En cambio, mezclas ternarias con un PC con mayor contenido en C 3 A y álcalis tienen más lenta generación de resistencias mecánicas iniciales, pero mayores a medida que avanza la hidratación.

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“…In Section 6.3.2, the influence of voxel size on the predictions of the effective elastic modulus at early ages of cement pastes will be analysed. Moreover, Young's modulus may be influenced by cohesion between solid particles, and not only by their contact as it was reported by Torrenti and Benboudjema [35]. This effect, which was named as "mechanical percolation threshold" [35], was not included in the mechanical FEM model.…”

Section: Experimental Vs Numerical Resultsmentioning

confidence: 98%

“…Moreover, Young's modulus may be influenced by cohesion between solid particles, and not only by their contact as it was reported by Torrenti and Benboudjema [35]. This effect, which was named as "mechanical percolation threshold" [35], was not included in the mechanical FEM model. In the case of the lattice model, an averaged property of two connected solid phases was defined for the interface beams, which may not represent the real cohesion formed between the solid particles.…”

Section: Experimental Vs Numerical Resultsmentioning

confidence: 98%

Microstructure-Based Prediction of the Elastic Behaviour of Hydrating Cement Pastes

Mazaheripour

Faria

et al. 2018

Applied Sciences

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The development of the elastic properties of a hardening cement paste results from the microstructural evolution due to cement hydration. The elastic behaviour of cement paste can be predicted by a combination of the hydration model and micromechanical analysis, which originates from a microstructural representative volume where the elastic behaviour of different hydrating cement products can be recognised. In this paper, the formation of the microstructural volume is simulated with the computational code HYMOSTRUC3D for cement hydration. The obtained microstructure is an input for a micromechanical modelling. A 3D regular lattice model is proposed to predict the elastic modulus of the microstructure, considering a water-to-cement (w/c) ratio within the range [0.30-0.50]. In addition, the Finite Element Method (FEM) is used to compare and validate the results from the lattice model. Predictions from these two modelling approaches are then compared to the experimental results provided by the EMM-ARM (Elasticity Modulus Measurement through Ambient Response Method) testing technique, the latter allowing measurement of the elastic modulus of hydrating cement pastes. Finally, the above-referred numerical models are used to evaluate the influence of the following features: the particle size distribution of the cement grains, the microstructure discretisation refinement and the elastic modulus of the C-S-H cement hydration product.

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Mechanical threshold of cementitious materials at early age

Cited by 42 publications

References 9 publications

Unloading‐Based Stiffness Characterisation of Cement Pastes During the Second, Third and Fourth Day After Production

Unloading‐Based Stiffness Characterisation of Cement Pastes During the Second, Third and Fourth Day After Production

Influence of the synergy between mineral additions and Portland cement in the physical-mechanical properties of ternary binders

Microstructure-Based Prediction of the Elastic Behaviour of Hydrating Cement Pastes

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