K. Van Breugel | Delft University of Technology (original) (raw)
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Papers by K. Van Breugel
Cement and Concrete Composites, 2014
ABSTRACT Innovative cement-based repair materials may require different procedures for applicatio... more ABSTRACT Innovative cement-based repair materials may require different procedures for application in comparison to standard repair requirements. Before their field application, a proper protocol should be established. Apart from laboratory experiments, numerical simulation can be of great use. Herein, a lattice type model is used to simulate fracture performance of fiber reinforced repair material - strain hardening cementations composite (SHCC) and its performance in the repair system. Repair material was first tailored through numerical testing in a single fiber pullout test and a direct tension test. Further on, structural behavior of the repair system and impact of initial defects in the mortar substrate (reflective cracking) was examined. The influence of fiber addition, different simulated substrate roughness and interface properties between new and old material on the performance of the repair system is investigated. Fracture propagation and sequence of crack development obtained by simulation is compared to experimental results. The numerical study gives insight into the benefits of distributed microcracking and high ductility of the fiber reinforced system over localized cracking and inherent brittleness of a non-reinforced repair system. It is envisioned that this approach can be used to tailor the properties of the repair system for specific applications, resulting in more reliable and durable concrete repairs in the future.
Construction and Building Materials, 2012
The mass diffusivity in Portland cement paste plays an important role in the durability design an... more The mass diffusivity in Portland cement paste plays an important role in the durability design and assessment of cement-based materials. This paper presents a link between mass diffusivity in cement paste and its microstructure. X-ray computed microtomography (lCT) was applied to derive the three-dimensional (3D) images of cement paste specimens with water-to-cement (w/c) ratio 0.50 at curing ages of 1, 3, 7, 28 and 120 days at a resolution of 0.485 lm/voxel. By choosing the image threshold value based on the gray level histogram, the phases, i.e., capillary pores, hydration products and unhydrated cement grains in the microtomography images of each specimen were segmented and the 3D microstructure and pore structure were obtained. The degree of pore connectivity and percolation of each specimen were analyzed in detail on the basis of cluster-labeling algorithm. In addition, the finite element method (FEM) was applied to simulate the diffusion process of tritiated water through the extracted microstructure and quantify the diffusivity of tritiated water by associating with Fick's law. The simulated diffusivity was compared with the measured value and seemed consistent with the experimental investigation. The results suggest that X-ray lCT is a reliable non-destructive technique and suitable tool to investigate the 3D microstructure. The obtained microstructure can be considered as an input to predict the transport properties of cementbased materials.
Calcium leaching is one of the important degradation mechanisms causing dissolution of the crysta... more Calcium leaching is one of the important degradation mechanisms causing dissolution of the crystal- line phases such as, AFm, portlandite increasing capillary porosity. Further it leads to decalcification of an amorphous C-S-H phase causing increase in the gel porosity and in turn degrading the long term performance of concrete structures. In this paper a lattice Boltzmann based pore-scale reactive transport approach in the context of simulating the evolution of microstructure of a hardened cement paste during calcium leaching is presented. This approach is based on fundamental principles of chemical thermodynamics and mass transport. The example presented illustrates influence of location of mineral grains and surface area on overall dissolution rate and pore structure evolution.
Journal of Wuhan University of Technology-Mater. Sci. Ed., 2010
ABSTRACT
Advances in Construction Materials 2007, 2007
In order to investigate the probability of cracking of hardening concrete in terms of the maximal... more In order to investigate the probability of cracking of hardening concrete in terms of the maximal allowable crack width, a full-scale concrete element has been evaluated. For this, evaluation, In order to investigate this issue, a concrete element has been simulated which measures a thickness of 1m and a height of 3m. The length deformations of the wall are considered to be fully restraint by 100%. The ambient conditions are taken into account, as well as the concrete mix parameters (see Table 1). TEMPSPAN, which is an acronym for TEMPeratuur (temperature) and SPANningen (stresses), is used to calculate the hardening stresses which develop during hardening.
Ultra high performance concrete (UHPC) has become one of promising concretes in the last decade b... more Ultra high performance concrete (UHPC) has become one of promising concretes in the last decade because of its excellent performance, such as high strength, low permeability and very good durability. However, like high performance concrete, UHPC is also subjected to high autogenous shrinkage due to high amount of cement and silica fume used. Seeking the ways to reduce the autogenous shrinkage is a very important task in the field of cement and concrete research. In this paper, the Rice husk ash, an agriculture waste, is explored to mitigate the autogenous shrinkage of UHPC. With high amorphous SiO2 content and special porous structure, the RHA shows not only reduce the cost and improve the early age properties of the UHPC but also increase the environmental benefits.
Cement and Concrete Composites, 2014
ABSTRACT Innovative cement-based repair materials may require different procedures for applicatio... more ABSTRACT Innovative cement-based repair materials may require different procedures for application in comparison to standard repair requirements. Before their field application, a proper protocol should be established. Apart from laboratory experiments, numerical simulation can be of great use. Herein, a lattice type model is used to simulate fracture performance of fiber reinforced repair material - strain hardening cementations composite (SHCC) and its performance in the repair system. Repair material was first tailored through numerical testing in a single fiber pullout test and a direct tension test. Further on, structural behavior of the repair system and impact of initial defects in the mortar substrate (reflective cracking) was examined. The influence of fiber addition, different simulated substrate roughness and interface properties between new and old material on the performance of the repair system is investigated. Fracture propagation and sequence of crack development obtained by simulation is compared to experimental results. The numerical study gives insight into the benefits of distributed microcracking and high ductility of the fiber reinforced system over localized cracking and inherent brittleness of a non-reinforced repair system. It is envisioned that this approach can be used to tailor the properties of the repair system for specific applications, resulting in more reliable and durable concrete repairs in the future.
Construction and Building Materials, 2012
The mass diffusivity in Portland cement paste plays an important role in the durability design an... more The mass diffusivity in Portland cement paste plays an important role in the durability design and assessment of cement-based materials. This paper presents a link between mass diffusivity in cement paste and its microstructure. X-ray computed microtomography (lCT) was applied to derive the three-dimensional (3D) images of cement paste specimens with water-to-cement (w/c) ratio 0.50 at curing ages of 1, 3, 7, 28 and 120 days at a resolution of 0.485 lm/voxel. By choosing the image threshold value based on the gray level histogram, the phases, i.e., capillary pores, hydration products and unhydrated cement grains in the microtomography images of each specimen were segmented and the 3D microstructure and pore structure were obtained. The degree of pore connectivity and percolation of each specimen were analyzed in detail on the basis of cluster-labeling algorithm. In addition, the finite element method (FEM) was applied to simulate the diffusion process of tritiated water through the extracted microstructure and quantify the diffusivity of tritiated water by associating with Fick's law. The simulated diffusivity was compared with the measured value and seemed consistent with the experimental investigation. The results suggest that X-ray lCT is a reliable non-destructive technique and suitable tool to investigate the 3D microstructure. The obtained microstructure can be considered as an input to predict the transport properties of cementbased materials.
Calcium leaching is one of the important degradation mechanisms causing dissolution of the crysta... more Calcium leaching is one of the important degradation mechanisms causing dissolution of the crystal- line phases such as, AFm, portlandite increasing capillary porosity. Further it leads to decalcification of an amorphous C-S-H phase causing increase in the gel porosity and in turn degrading the long term performance of concrete structures. In this paper a lattice Boltzmann based pore-scale reactive transport approach in the context of simulating the evolution of microstructure of a hardened cement paste during calcium leaching is presented. This approach is based on fundamental principles of chemical thermodynamics and mass transport. The example presented illustrates influence of location of mineral grains and surface area on overall dissolution rate and pore structure evolution.
Journal of Wuhan University of Technology-Mater. Sci. Ed., 2010
ABSTRACT
Advances in Construction Materials 2007, 2007
In order to investigate the probability of cracking of hardening concrete in terms of the maximal... more In order to investigate the probability of cracking of hardening concrete in terms of the maximal allowable crack width, a full-scale concrete element has been evaluated. For this, evaluation, In order to investigate this issue, a concrete element has been simulated which measures a thickness of 1m and a height of 3m. The length deformations of the wall are considered to be fully restraint by 100%. The ambient conditions are taken into account, as well as the concrete mix parameters (see Table 1). TEMPSPAN, which is an acronym for TEMPeratuur (temperature) and SPANningen (stresses), is used to calculate the hardening stresses which develop during hardening.
Ultra high performance concrete (UHPC) has become one of promising concretes in the last decade b... more Ultra high performance concrete (UHPC) has become one of promising concretes in the last decade because of its excellent performance, such as high strength, low permeability and very good durability. However, like high performance concrete, UHPC is also subjected to high autogenous shrinkage due to high amount of cement and silica fume used. Seeking the ways to reduce the autogenous shrinkage is a very important task in the field of cement and concrete research. In this paper, the Rice husk ash, an agriculture waste, is explored to mitigate the autogenous shrinkage of UHPC. With high amorphous SiO2 content and special porous structure, the RHA shows not only reduce the cost and improve the early age properties of the UHPC but also increase the environmental benefits.