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Nguyen, V.P. (author), Stroeven, M. (author), Sluys, L.J. (author)
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...
conference paper 2009
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Rots, J.G. (author), Invernizzi, S. (author), Belleti, B. (author), Hendriks, M.A.N. (author)
conference paper 2009
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Schipper, H.R. (author)
Due to the complexity of the freeform shapes it is often not possible to distinguish any repetitive elements in freeform buildings at all. Most freeform building designs consist of many single or double curved surfaces which require complex shapes for the mould and element edges. Since the costs of the moulds (formwork) for precast concrete make...
conference paper 2010
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Wiktor, V.A.C. (author), Jonkers, H.M. (author)
conference paper 2011
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Stroeven, P. (author), Huan, H. (author)
The paper focuses on the quality of predicting the damage characteristics of the loaded engineering structure by subjecting section images of cores supposedly drawn from the concrete of the structure to quantitative image analysis by sweeping test lines. Automation of this data acquisition stage is shown, generally leading to information that is...
conference paper 2011
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Stroeven, P. (author), Le, N.L.B. (author), Stroeven, M. (author), Sluys, L.J. (author)
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...
conference paper 2011
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Grünewald, S. (author), Janssen, B. (author), Schipper, H.R. (author), Vollers, K.J. (author), Walraven, J.C. (author)
This paper discusses the effect of intentional deformation of a flexible formwork after casting of the concrete and the influence of the characteristics of concrete in the fresh state on the quality of a concrete element. This deformation is intended to bring the concrete element in its desired final shape; the deformation typically takes place...
conference paper 2012
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Stroeven, P. (author), He, H. (author), Le, L.B.N. (author)
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...
conference paper 2012
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Stroeven, P. (author), He, H. (author)
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...
conference paper 2013
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Slobbe, A.T. (author), Hendriks, M.A.N. (author), Rots, J.G. (author)
This paper presents a dedicated numerical test that enables to assess the directional mesh bias of constitutive models in a systematic way. The test makes use of periodic boundary conditions, by which strain localization can be analyzed for different mesh alignments with preservation of mesh uniformity and with exclusion of boundary disturbances...
conference paper 2013
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Weerheijm, J. (author), Sharma, A. (author), Ozbolt, J. (author)
The behavior of concrete structures is strongly influenced by the loading rate. Compared to quasi-static loading, on meso and macro-scale concrete loaded by impact loading acts in a different way. First, there is a strain-rate influence on strength, stiffness, ductility, and, second, there are inertia forces activated which influence the...
conference paper 2013
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Weerheijm, J. (author), Lu, Y. (author), Xu, J. (author)
This paper presents a numerical modelling study on the simulation of the cracking process and fracture energy in concrete under high strain rate. To capture the stress wave effect and the damage evolution at the meso-length scale, both a homogeneous model with a millimetreresolution mesh and an explicit heterogeneous mesoscale model with random...
conference paper 2013
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Mors, R.M. (author), Jonkers, H.M. (author)
A functional experimental concrete system has been developed in our lab, in which a two component bacteria-based healing agent contained in a protective reservoir is included in the concrete mixture. Incorporated bacteria have the potential to produce copious amounts of calcium carbonate based crystals from supplied mineral precursor compounds....
conference paper 2013
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Zemskov, S.V. (author), Copuroglu, O. (author), Vermolen, F.J. (author)
A mathematical model for the post-damage recovery of carbonated cement is described. The model is based on a two-dimensional initial-boundary value problem for a system of partial differential equations. The study is embedded within the framework of investigating the effect of using lightweight expanded clay aggregate, which is incorporated into...
conference paper 2013
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Sangadji, S. (author), Wiktor, V.A.C. (author), Jonkers, H.M. (author), Schlangen, H.E.J.G. (author)
Bacteria induced calcite precipitation has been proven to be effective in making concrete structure self-healing. In Microlab TU Delft, the concept has been enhanced by developing a liquid bacteria-based concrete repair system. The solution contains calcite precipitating bacteria, nutrients and buffer compound which may demonstrate high...
conference paper 2013
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Wiktor, V.A.C. (author), Sangadji, S. (author), Jonkers, H.M. (author), Schlangen, H.E.J.G. (author)
Bacterially induced calcium carbonate precipitation has received considerable attention for its potential application in enforcing or repairing construction material. The mechanism of bacterially mediated calcite precipitation in those studies is primarily based on the enzymatic hydrolysis of urea. Besides calcite precipitation, this reaction...
conference paper 2013
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Palin, D. (author), Wiktor, V. (author), Jonkers, H.M. (author)
Marine concrete structures are exposed to one of the most hostile of natural environments. Many physical and chemical phenomena are usually interdependent and mutually reinforcing in the deterioration of marine exposed concrete: expansion and microcracking due to physical effects increases concrete permeability paving the way for harmful...
conference paper 2013
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Varini, M. (author), Koleva, D.A. (author), Denkova, A.G. (author), Mol, J.M.C. (author), Terryn, H. (author), Van Breugel, K. (author)
Polymeric nano-materials utilization in reinforced concrete, aiming to deal with steel corrosion was developed in previous works. Promising results were obtained with PEO–b–PS nano-formations, both in terms of enhanced bulk matrix properties and improved steel corrosion resistance. Recent research has been focusing on a cheaper and commercially...
conference paper 2013
document
Wiktor, V.A.C. (author), Jonkers, H.M. (author)
This paper focuses particularly on the ageing of concrete due to micro-crack formation or freeze/thaw which results in an increased permeability of the concrete. The bacteria-based repair system presented in this paper aims at recovering the concrete permeability thanks to bacteria-induced calcium carbonate precipitation inside cracks/porosity....
conference paper 2014
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Pradena, M. (author), Houben, L.J.M. (author)
Concrete pavements (CPs) are durable and they do not need periodic invasive maintenance interventions. Nevertheless, CPs are hardly chosen when only initial costs, instead of life-cycle costs, are considered in the evaluation. Nowadays, there are innovations in Jointed Plain Concrete Pavements (JPCPs) that reduce initial costs about 25% with...
conference paper 2014
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