Cement and Concrete Characterization by Scanning Electron Microscopy
The scanning electron microscope (SEM) is a powerful tool for the microstructural and chemical characterization of cement and concrete. Imaging techniques such as secondary electron, backscattered...
Simulation of Failure Processes in Cementitious Particle Composites
Progressive failure analysis in cementitious particle composites such as concrete requires a realistic description of the topology of the composite structure and the interaction of the...
Material Testing at High Pressure
A static test cell has been designed and fabricated to apply a peak stress of up to 2 GPa to a 2.54 cm cylindrical specimen. The cell design was based on the 'belt'...
Mechanical Behavior of Composites with Interphases
The effect of interphases on the mechanical behavior of fiber-reinforced composites is studied. Two problems, a cracked fiber in a matrix, and a fiber pulled out of a matrix, are discussed....
Theoretical and Experimental Mechanisms of Toughening in Multi-phase Materials
Multi-phase materials are an important class of materials being developed for aerospace primary structural applications. Multi-phase materials are those materials consisting of two or...
On Statistical Micromechanical Process Damage Models for Brittle Solids with Interacting Microcracks
Two-dimensional micromechanical damage models with strongly interacting microcracks are presented to investigate the overall nonlinear mechanical responses of microcrack-weakened brittle...
Nonlocality of Continuum Approximation of Microcracked Materials
A continuum with nonlocal damage has recently been shown to be an effective approach for the analysis of strain-softening structures. The basic idea is that only the damage, normally caused...
Moisture Diffusion in Concrete and Mechanisms of Drying Creep
The Pickett effect is the excess of creep at drying over the sum of shrinkage and basic creep. Several theoretical models have been presented to speculate on the mechanisms of this effect,...
Deformation of Concrete Due to Drying
The deformation of drying concrete is numerically investigated considering the effect of random arrangement of coarse aggregates. The result indicates that a part of the statistical variation...
A Phenomenological Approach to Physico Chemical Phenomena Coupled with Damage in Massive Concrete
This paper presents the first experiments which have been done to support the bases of a thermomechanical model coupled with damage and to identify the characteristics parameters needed...
A Model to Predict Restrained Shrinkage Cracking of Fiber Reinforced Concrete
Cracking due to restrained shrinkage occurs very often in an engineering practice, causing serious problems such as increased water permeability of the structure and corrosion of the reinforcement....
Influence of Finite Deformations in the Stress-Strain Modelling of Granular Media
An incremental formulations of the stress-strain law is presented for quasi-static deformation of granular solids. The stress-strain relationship is derived for an element of granular...
Instability and Plastic Flow of Soils
Materials should according to Drucker's postulate become unstable when the second increment of plastic work is negative. Experimental observations however show otherwise....
A Micromechanics Model for Rough Interfaces
A new constitutive model for transfer of interfacial tractions along rough cracks in strain softening composites is presented. The model relates the normal and shearing stresses on the...
Constitutive Relations for Granular Solids Accounting for Heterogeneous Deformation Fields
Under high deviatoric stress levels corresponding to large strains, the deformation of granular media is highly heterogeneous. A micro-mechanical approach is developed here to model the...
An Ellipse-based Micromechanical Model for Angular Granular Materials
An ellipse-based two-dimensional Discrete Element algorithm for numerically modeling angular granular materials is developed and presented. Interparticle contact computations require the...
Geometry of Yield Surfaces for Frictional Flow of Granular Materials
In the frictional flow regime, the discrete particles which compose of granular material roll or slide over one another, maintaining essentially continuous contact. Many theorists, including...
Numerical Experiments for Anisotropic Behavior of Granular Materials
A three dimensional discrete element computer code 'TRUBAL' is used to investigate the effect of initial anisotropy on stress-strain and volume change characteristics...
Instability in Granular Chute Flows
Numerical simulations showed that granular flows in a vertical chute can flow as a steady, uniform stream or as an intermittent slug flow. In numerical experiments slugs or grouping of...
Computer Simulations of Rapid Granular Flows Interacting with a Flat, Frictional Boundary
This paper compares the results of numerical simulations for the rapid, steady flow of identical spheres colliding with a flat frictional boundary with the recent predictions of Jenkins...
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