How to measure path length?

Path length measuring is a relevant engineering problem. Leonardo Da Vinci designed for the military appropriate equipment, the podometer, to do so. Modern equipment such as step meters and map meters are quite similar to Da Vinci?s design, despite geometrical statistical - stereological - methods based on theorems of Cauchy and Buffon that were...

Demonstration and validation by simple examples of a complete analogue porosimetry methodology for virtual cement pastes on micro-level

Details of a complete methodology for porosimetry of virtual concrete have been described in a series of publications. This paper shortly sketches the main characteristics, whereupon it is indicated how a pore network model is designed based on data extracted from the virtual cement paste. This involves smoothing the main trunks as the main pore...

Liquid water permeability of partially saturated cement paste assessed by dem-based methodology

Permeability of virtual cement seems to exceed experimental data by several orders of magnitude. The differences may actually not be that dramatic, since experimental samples are in practice not always fully saturated as generally assumed. This paper demonstrates that this has enormous effects on permeability. A numerical study is conducted on...

Packing issue in cement blending for sustainability developments - Approach by discrete element method

Common cement blending materials for concrete like fly ashes, blast furnace slag, silica fume, metakaolin and rice husk ash have been investigated experimentally as to their impact on concrete’s mechanical, physical and sustainability capabilities. Such efforts offer but case-related information on involved materials and used procedures....

Strategy for predicting transport-based durability properties of concrete based on DEM approach

Modeling possibilities of concrete structure for durability purposes

Evaluation by discrete element method (DEM) of gap-graded packing potentialities for green concrete design

Partial replacement of Portland cement by pozzolanic mineral admixtures exerts direct positive effects on CO2 emissions. The green character is reinforced by making use of incinerated vegetable waste, such as rice husk ash (RHA). Gap-grading leads to improved particle packing density with RHA as the fine component, so that high strength concrete...

C-S-H globule clustering on nano-scale simulated by the discrete element method for pore structure exploration

Strategy for exploring the pore structure of cementitious materials based on a DEM approach (poster)

Porosimetry by DraMuTS applied to DEM-produced cementitious materials

Porosimetry of matured cementitious materials is of hiigh interest, because durability is governed by the capillary pore network structure. Experimental approaches are time-consuming, laborious and thus expensive. Fast developments in computer technology make it nowadays possible quite realistically producing cementitious materials in virtual...

Packing of non-spherical aggregate particles by DEM

Loose random and dense random mono-size pacl<ing states were investigated by the discrete element modelling (DEM) for eight types of polyhedral grains, for ellipses with different aspect ratio, for cubes and for spheres. Focus was on density, sphericity of the grains and average value and frequency distribution of coordination number. The 3D...

Analogue simulation by dem of material structure for property estimation of cementitious materials

Realistic simulation of particulate materials like concrete on meso- as well as micro-level is nowadays possible by fast developments in computer technology. This would be a more economic way than by physical experiinents, which are more time-consuming, laborious and thus expensive. This concern the production of the aggregate structure or of...

Discrete element modeling approach to porosimetry for durability risk estimation of concrete

The paper introduces a novel approach to porosimetry in virtual concrete, denoted as random node structuring (RNS). The fresh state of this particulate material is produced by the DEM system HADES. Hydration simulation is a hybrid approach making use of wellknown discretization and vector methods. Particle interferences (overlap) in the dynamic...

Methodology of modeling fiber reinforcement in concrete elements

This paper’s focus is on the modeling methodology of (steel) fiber reinforcement in concrete. The orthogonal values of fiber efficiency are presented. Bulk as well as boundary situations are covered. Fiber structure is assumed due to external compaction by vibration to display a partially linear planar structure (Stroeven-concept), which can...

On a micro-meso two-scale damage model for concrete

In this contribution, we present the mechanical behaviour of the hardening cement paste explicitly taking into account its complex microstructure. The microstructure of the cement paste is obtained via numerical cement hydration simulation. A simple nonlocal isotropic damage model is adopted for different constituents of the cement paste. The...

Enhanced domain decomposition techniques for the modeling of softening materials

In this study a FETI: Finite Element Tearing and Interconnecting [1] technique is adopted and exploited for the efficient and accurate modeling of softening materials such as concrete and rock. A fie scale analysis in which concrete is modelled as a three-phase material is used. Special attention is given to the treatment of linear and non...