Documents disponibles écrits par cet auteur

Influence of aggregate size and volume fraction on shrinkage induced micro-cracking of concrete and mortar / Peter Grassl in Cement and concrete research, Vol. 40 N° 1 (Janvier 2010) 

Public ISBD [article]  in Cement and concrete research > Vol. 40 N° 1 (Janvier 2010) . - pp. 85-93 Titre : Influence of aggregate size and volume fraction on shrinkage induced micro-cracking of concrete and mortar Type de document : texte imprimé Auteurs : Peter Grassl, Auteur ; Hong S. Wong, Auteur ; Nick R. Buenfeld, Auteur Article en page(s) : pp. 85-93 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Microcracking  Interfacial  transition  zone  Transport  properties  Shrinkage  Aggregate  Lattice  modelling Index. décimale : 691 Matériaux de construction. Pièces et parties composantes Résumé : In this paper, the influence of aggregate size and volume fraction on shrinkage induced micro-cracking and permeability of concrete and mortar was investigated. Nonlinear finite element analyses of model concrete and mortar specimens with regular and random aggregate arrangements were performed. The aggregate diameter was varied between 2 and 16 mm. Furthermore, a range of volume fractions between 0.1 and 0.5 was studied. The nonlinear analyses were based on a 2D lattice approach in which aggregates were simplified as monosized cylindrical inclusions. The analysis results were interpreted by means of crack length, crack width and change of permeability. The results show that increasing aggregate diameter (at equal volume fraction) and decreasing volume fraction (at equal aggregate diameter) increase crack width and consequently greatly increases permeability. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235562%23 [...] [article] Influence of aggregate size and volume fraction on shrinkage induced micro-cracking of concrete and mortar [texte imprimé] / Peter Grassl, Auteur ; Hong S. Wong, Auteur ; Nick R. Buenfeld, Auteur . - pp. 85-93. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 40 N° 1 (Janvier 2010) . - pp. 85-93 Mots-clés : Microcracking  Interfacial  transition  zone  Transport  properties  Shrinkage  Aggregate  Lattice  modelling Index. décimale : 691 Matériaux de construction. Pièces et parties composantes Résumé : In this paper, the influence of aggregate size and volume fraction on shrinkage induced micro-cracking and permeability of concrete and mortar was investigated. Nonlinear finite element analyses of model concrete and mortar specimens with regular and random aggregate arrangements were performed. The aggregate diameter was varied between 2 and 16 mm. Furthermore, a range of volume fractions between 0.1 and 0.5 was studied. The nonlinear analyses were based on a 2D lattice approach in which aggregates were simplified as monosized cylindrical inclusions. The analysis results were interpreted by means of crack length, crack width and change of permeability. The results show that increasing aggregate diameter (at equal volume fraction) and decreasing volume fraction (at equal aggregate diameter) increase crack width and consequently greatly increases permeability. DEWEY : 620.13 ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235562%23 [...]

Mesoscale approach to modeling concrete subjected to thermomechanical loading / Peter Grassl in Journal of engineering mechanics, Vol. 136 N° 3 (Mars 2010) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 136 N° 3 (Mars 2010) . - pp. 322-328 Titre : Mesoscale approach to modeling concrete subjected to thermomechanical loading Type de document : texte imprimé Auteurs : Peter Grassl, Auteur ; Pearce, Chris, Auteur Article en page(s) : pp. 322-328 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Concrete  Cracking  Thermal  analysis  Plasticity  Strains  Load  factors. Résumé : Concrete subjected to combined compressive stresses and temperature loading exhibits compressive strains, which are considerably greater than for concrete subjected to compressive stresses alone. This phenomenon is called transient thermal creep or load induced thermal strain and is usually modeled by macroscopic phenomenological constitutive laws which have only limited predictive capabilities. In the present study a mesoscale modeling approach is proposed in which the macroscopically observed transient thermal creep results from the mismatch of thermal expansions of the mesoscale constituents. The mesostructure of concrete is idealized as a two-dimensional three-phase material consisting of aggregates, matrix, and interfacial transition zones. The nonlinear material response of the phases is described by a plasticity interface model. The mesoscale approach was applied to analyze compressed concrete specimens subjected to uniform temperature histories and the analysis results were compared to experimental results reported in the literature. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...] [article] Mesoscale approach to modeling concrete subjected to thermomechanical loading [texte imprimé] / Peter Grassl, Auteur ; Pearce, Chris, Auteur . - pp. 322-328. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 136 N° 3 (Mars 2010) . - pp. 322-328 Mots-clés : Concrete  Cracking  Thermal  analysis  Plasticity  Strains  Load  factors. Résumé : Concrete subjected to combined compressive stresses and temperature loading exhibits compressive strains, which are considerably greater than for concrete subjected to compressive stresses alone. This phenomenon is called transient thermal creep or load induced thermal strain and is usually modeled by macroscopic phenomenological constitutive laws which have only limited predictive capabilities. In the present study a mesoscale modeling approach is proposed in which the macroscopically observed transient thermal creep results from the mismatch of thermal expansions of the mesoscale constituents. The mesostructure of concrete is idealized as a two-dimensional three-phase material consisting of aggregates, matrix, and interfacial transition zones. The nonlinear material response of the phases is described by a plasticity interface model. The mesoscale approach was applied to analyze compressed concrete specimens subjected to uniform temperature histories and the analysis results were compared to experimental results reported in the literature. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...]

Random lattice-particle simulation of statistical size effect in quasi-brittle Structures failing at crack initiation / Peter Grassl in Journal of engineering mechanics, Vol. 135 N°2 (Février 2009) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 135 N°2 (Février 2009) . - pp. 85-92 Titre : Random lattice-particle simulation of statistical size effect in quasi-brittle Structures failing at crack initiation Type de document : texte imprimé Auteurs : Peter Grassl, Auteur ; Zdenek P. Bazant, Auteur Article en page(s) : pp. 85-92 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Concrete  Material  properties  Size  effect  Cracking  Statistics  Structural  reliability. Résumé : The modeling of statistical size effect of concrete structures that fail at crack initiation is studied, with special attention to the interaction between the autocorrelation length and the size of the failure zone. The mechanical failure of concrete is modeled by a network of axial springs with degrading stiffness. The heterogeneity of concrete is idealized by spatial variation of the tensile strength and fracture energy. As an example, the direct tensile test in plane stress, with the size range of 1:20, is simulated. Furthermore, simulations of a four-point bending test with varying bending span are compared to the experimental results reported in the literature. The interaction of the autocorrelation length and the size of the failure zone is identified as a key parameter for the modeling of statistical size effect DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...] [article] Random lattice-particle simulation of statistical size effect in quasi-brittle Structures failing at crack initiation [texte imprimé] / Peter Grassl, Auteur ; Zdenek P. Bazant, Auteur . - pp. 85-92. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 135 N°2 (Février 2009) . - pp. 85-92 Mots-clés : Concrete  Material  properties  Size  effect  Cracking  Statistics  Structural  reliability. Résumé : The modeling of statistical size effect of concrete structures that fail at crack initiation is studied, with special attention to the interaction between the autocorrelation length and the size of the failure zone. The mechanical failure of concrete is modeled by a network of axial springs with degrading stiffness. The heterogeneity of concrete is idealized by spatial variation of the tensile strength and fracture energy. As an example, the direct tensile test in plane stress, with the size range of 1:20, is simulated. Furthermore, simulations of a four-point bending test with varying bending span are compared to the experimental results reported in the literature. The interaction of the autocorrelation length and the size of the failure zone is identified as a key parameter for the modeling of statistical size effect DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...]