Veerle Cnudde

Veerle Cnudde
Ghent University | UGhent · Department of Geology

Professor

About

331
Publications
80,930
Reads
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9,985
Citations
Citations since 2017
124 Research Items
6753 Citations
201720182019202020212022202302004006008001,0001,2001,400
201720182019202020212022202302004006008001,0001,2001,400
201720182019202020212022202302004006008001,0001,2001,400
201720182019202020212022202302004006008001,0001,2001,400
Additional affiliations
October 2010 - present
Ghent University
Position
  • Professor

Publications

Publications (331)
Article
Advanced chemical and mineralogical techniques are necessary to further our understanding of ore deposits and their genesis. Using X-ray micro-computed tomography (µCT) and an automated mineralogy (AM) system based on scanning electron microscopy with an energy-dispersive X-ray spectrometer (SEM–EDX), we investigated the internal mineralogy of Sn–N...
Preprint
Norilsk sulfide ores are one of the largest known sources of Pd on Earth. Palladium in these ores is presented in platinum-group minerals (PGM) and base metal sulfides (BMS), especially in pentlandite ((Fe,Ni)9 S8). Although several studies demonstrated high concentrations along with heterogeneous distribution of Pd in pentlandites from Norilsk, th...
Article
Full-text available
Damage to porous materials in heritage buildings caused by salt mixture crystallization is driven by the surrounding environmental conditions. To understand the crystallization behavior of a mixed salt solution as a function of changing climatic conditions (i.e., relative humidity and temperature), excluding factors such as the internal pore struct...
Article
Full-text available
Mineral building materials suffer from weathering processes such as salt efflorescence, freeze–thaw cycling, and microbial colonization. All of these processes are linked to water (liquid and vapor) in the pore space. The degree of damage following these processes is heavily influenced by pore space properties such as porosity, pore size distributi...
Article
Full-text available
Understanding salt mixtures in the built environment is crucial to evaluate damage phenomena. This contribution presents charge balance calculations applied to a dataset of 11412 samples taken from 338 sites, building materials showing signs of salt deterioration. Each sample includes ion concentrations of Na⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, NO3⁻, and SO4²⁻...
Article
Maastricht Stone is a soft and porous, pale limestone from the Krijtland, a geological region with Late Cretaceous outcrops across the border of Belgium, The Netherlands, and Germany. It has a remarkably high porosity and low strength; however, the stone is very durable in a diverse range of outdoor applications. The stone has been used since Roman...
Conference Paper
Full-text available
Ore geology research conventionally relies on macroscopic and microscopic two dimensional (2D) observations of hand specimens and thin or polished sections. Although 2D techniques such as optical microscopy and scanning electron microscopy (SEM) are well-known and, therefore, commonly used for the characterization of ore samples, they are not capab...
Article
Full-text available
Quantitatively assessing attenuation and dispersion of elastic‐wave velocities in partially saturated reservoir is difficult because of its sensitivity to fluid distribution. We conducted experiments on homogeneous Indiana limestone samples, partially saturated by two methods: drying and imbibition which lead to different fluid distribution for a g...
Article
Full-text available
The Mt. Rudnaya MSS-ISS (monosulfide and intermediate solid solution) fine-grained ores from a NE termination of Norilsk 1 deposit were analyzed using a combination of X-ray computed micro tomography, spectral X-ray computed micro tomography and scanning electron microscopy to achieve both, 2D and 3D data. The ores consist of ISS composed of tiny l...
Article
Full-text available
Commonwealth war cemeteries commemorate the fallen of both world wars. Every casualty is remembered with a memorial or on a headstone. However, the headstones need to be maintained extensively, as microorganisms easily colonise them, affecting legibility and the stone substrate in the longer term. In the past, pesticides and other chemicals were po...
Article
Water affects the susceptibility of stone to alteration by facilitating physical, chemical and biological weathering. Stone properties determine water transport and retention, but it is also expected that biofilms and extracellular polymeric substances (EPS) could alter the water‐stone relationship. A lot of research on this subject has been carrie...
Preprint
Full-text available
Fluid flow through intricate confining geometries often exhibits complex behaviors, certainly in porous materials, e.g. in groundwater flows or the operation of filtration devices and porous catalysts. However, it has remained extremely challenging to measure 3D flow fields in such micrometer-scale geometries. Here, we introduce a new 3D velocimetr...
Article
X-ray computed tomography (CT) can reveal the internal details of objects in three dimensions non-destructively. In this Primer, we outline the basic principles of CT and describe the ways in which a CT scan can be acquired using X-ray tubes and synchrotron sources, including the different possible contrast modes that can be exploited. We explain t...
Article
Full-text available
Plain Language Summary The flow of multiple fluids through a porous material plays an important role in many industrial and natural processes such as rain infiltrating a dry soil or CO2 storage in the subsurface. At the pore‐scale, these flows are governed by forces which depend on the pore‐geometry and the relative affinities of the fluids with th...
Article
Full-text available
Cracks in reinforced concrete are preferential ingress paths for aggressive substances such as chlorides. As soon as a critical amount of chlorides has reached the steel reinforcement, corrosion will occur. Therefore, crack healing is of utmost importance. However, manual crack repair is very labour intensive. Therefore, the potential of self-heali...
Article
Full-text available
In this study, the microstructure of mock-up mortar specimens for a historic environment, composed of different mixtures, was studied using mercury intrusion porosity (MIP) and microcomputed tomography (µCT), highlighting the advantages and drawbacks of both techniques. Porosity, sphericity, and pores size distribution were studied, evaluating chan...
Article
Microorganisms, including bacteria, archaea, algae and fungi, colonize natural building stones. Bacteria are among the most relevant colonizers, as they impact substrates in multiple forms, primarily attributed to their high diversity. They alter rock properties, induce discoloration, dissolution or precipitation, which can lead to degradation over...
Conference Paper
Full-text available
Ore deposit research conventionally relies on macroscopic and microscopic two dimensional (2D) observations of hand specimens and thin/polished sections. Microanalytical techniques are used to characterize the chemical and structural variations of millimeter-to centimeter-sized samples with a spatial resolution down to micrometer scales (Pearce et...
Article
Full-text available
X-ray computed micro-tomography typically involves a trade-off between sample size and resolution, complicating the study at a micrometer scale of representative volumes of materials with broad feature size distributions (e.g. natural stones). X-ray dark-field tomography exploits scattering to probe sub-resolution features, promising to overcome th...
Preprint
The mathematical models for the capillary-driven flow of fluids in tubes are typically assuming a static contact angle at the fluid-air contact line on the tube walls. However, the dynamic evolution of the fluid-air interface is an important feature during capillary rise. Furthermore, inertial effects are relevant at early times and may lead to osc...
Article
Earthquake doublets have been described in fault systems around the world but have not yet been confidently resolved in paleoseismic records. Our current knowledge is limited to historical occurrences, preventing researchers from uncovering potential patterns or recognizing common fault behavior. Identification of prehistoric doublets is thus of cr...
Article
Full-text available
Pore network model simulation (PNM) is an important method to simulate reactive transport processes in porous media and to investigate constitutive relationships between permeability and porosity that can be implemented in continuum-scale reactive-transport modelling. The existing reactive transport pore network models (rtPNMs) assume that the init...
Preprint
Full-text available
Fluid invasion into porous materials is very common in natural and industrial processes. The fluid invasion dynamics in simple pore networks are governed by a global balance of capillary, viscous and inertial forces. However, significant local variability in this balance may exist inside natural, heterogeneous porous materials. Here, we imaged slow...
Conference Paper
Full-text available
Ice crystallization is an important process for degradation of porous mineral building materials in moderate and cold climates. Many researchers have studied the internal stress build-up by the crystallization process. Nonetheless, direct observations of these internal ice crystals and the crystallization process are scarce. High-resolution X-ray c...
Article
Full-text available
The microstructure of alkali-reactive aggregates, especially the spatial distribution of the pore and reactive silica phase, plays a significant role in the process of the alkali silica reaction (ASR) in concrete, as it determines not only the reaction front of ASR but also the localization of the produced expansive product from where the cracking...
Data
The Archaeology and Geology Departments of Ghent University are proud to announce the launch of the online open-access reference collection FLEPOSTORE: Flemish Pottery & Stone Reference collection. It can be consulted online at: https://flepostore.ugent.be The reference collection focuses on pottery and stone found at archaeological sites and in hi...
Article
Full-text available
The applications of polymeric sponges are varied, ranging from cleaning and filtration to medical applications. The specific properties of polymeric foams, such as pore size and connectivity, are dependent on their constituent materials and production methods. Nuclear magnetic resonance imaging (MRI) and X-ray micro-computed tomography (µCT) offer...
Article
Full-text available
Salt weathering is one of the most important causes of deterioration in the built environment. Two crucial aspects need further investigation to understand the processes and find suitable measures: the impact of different climatic environments and the properties of salt mixture crystallization. We demonstrate the importance of kinetics in quantifyi...
Article
Full-text available
Sands exhibit a directional diversity in shear modulus at small strains, reflecting the anisotropic stiffness behaviour in the structure. In this paper, sample preparation method, particle shape and particle size are considered as parameters to produce samples with various initial fabric. Five preparation methods, namely, air and water pluviation,...
Article
Burnt lithic artefacts are regularly discarded from microwear analyses, causing a bias in the functional interpretation of prehistoric sites. This is especially true when burnt lithics are numerous as is typically the case on Mesolithic sites in Northern Belgium. Burnt stone artefacts potentially hold information regarding the functional, spatial,...
Article
Full-text available
Heterogeneous fracture aperture distribution, dictated by surface roughness, mechanical rock and fracture properties, and effective stress, limits the predictive capabilities of many reservoir‐scale models that commonly assume smooth fracture walls. Numerous experimental studies have probed key hydromechanical responses in single fractures; however...
Presentation
Earthquake doublets form a particular challenge for seismic hazard assessment and can provide insights into potentially characteristic fault behaviour. However, knowledge on this type of earthquake sequences is limited to information provided by historical archives as their identification in paleoseismic records is ambiguous. The continuous sedimen...
Article
A laboratory-based X-ray fluorescence (XRF) methodology is presented for standardless quantified analysis based on a monochromatic X-ray spectrometer coupled to Monte Carlo aided quantification. This procedure will be valuable for many scientific fields (e.g. archaeology, geology, etc.) where the unique nature of the investigated samples calls for...
Article
Full-text available
The through-thickness compressive behavior of fabric reinforcements is crucial in liquid composite molding manufacturing processes. Predictive simulations of the compressive response are thus necessary to enable a virtual processing workflow. These are complex however, as the compressive behavior of the reinforcement fabrics is non-linear. Altough...
Article
Full-text available
Solute transport processes are influenced by pore-scale heterogeneity. To study this, transient micron-scale solute concentration fields were imaged by fast laboratory-based X-ray micro-computed tomography. We performed tracer injection experiments in three types of porous material with increasing levels of heterogeneity (sintered glass, Bentheimer...
Article
Full-text available
Degradability of organic matter (OM) in soil depends on its spatial location in the soil matrix. A recent breakthrough in 3D-localization of OM combined dual-energy X-ray CT-scanning with OsO 4 staining of OM. The necessity for synchrotron-based µCT and the use of highly toxic OsO 4 severely limit applications in soil biological experiments. Here,...
Poster
This poster presents new results from various sample materials (e.g. pure elements, minerals, and rocks). Different pure elements were measured to compare positions of the theoretical K-edge energy with the measured one. Furthermore, we show the results of measurements of different monazite grains and their variation in the rare earth element compo...
Preprint
Full-text available
Salt weathering is one of the most important causes of deterioration in the built environment. Two crucial aspects need further investigation to understand the processes and find suitable measures: the impact of different climatic environments and the properties of salt mixture crystallization. We demonstrate the importance of kinetics in quantifyi...
Conference Paper
Low-permeability geological seals may be compromised by the occurrence of fluid-conductive fault and fracture systems, which can potentially transmit fluids away from the storage reservoir. We performed a systematic laboratory-based investigation into the effect of surface roughness on the fluid flow properties of both natural rock and 3D-printed f...
Conference Paper
Full-text available
Previous studies on the validation of the water absorption measuring techniques contact sponge method (CSM) and Kartsen tube (KT), have shown that the different methods are able to distinguish differences in pore structure, due to alterations or past treatments. These non destructive techniques have been developed for field measurements. The method...
Article
Full-text available
We present a new approach to 3-dimensional chemical imaging based on X-ray computed micro tomography (CT), which enables the analysis of the internal elemental chemistry. The method uses a conventional laboratory-based CT scanner equipped with a semiconductor detector (CdTe). Based on the X-ray absorption spectra, elements in a sample can be distin...
Article
Effective storage and containment of injected fluids, over a range of spatial and temporal scales, is reliant upon the sealing capacity of the lithologies overlying geological stores. Low-permeability mudrocks are considered effective candidates to restrict the migration of injected fluids from the host formation, owing to their low matrix permeabi...
Conference Paper
Temperature and strain measurements are often used to assess the internal processes occurring in natural stones subject to freeze-thaw cycles. Despite the known relation between the internal temperature and the pore size in which ice is crystallizing, not much effort has been done to use this relation to predict the ice content within relatively la...
Conference Paper
Microbes thrive in almost every possible environment, including natural building stones. Microbial communities affect these materials which can lead to biodeterioration. Among others, air pollution, especially SO2 and NOx, is an important actor for stone degradation. This leads to crust formation and in limestone typically to gypsum crusts. There a...
Article
Archaeological lithic assemblages are often affected by burning, as evident from severe thermal damage on these artefacts. In this study, the thermal alteration of four different flint types was investigated by performing controlled heating experiments in laboratory setting. The resulting heat alterations were afterwards compared to heating of flin...
Article
Full-text available
Investigation of biofilms and visualization using non-destructive imaging techniques like X-ray CT has recently gained interest. Biofilms are congregations of microorganisms that attach to surfaces and comprise of microbial cells embedded in extracellular polymeric substances (EPS). They are ubiquitous entities that are commonly found in any non-st...
Article
Predicting the solute dispersivity in porous media is complicated by the known scale dependency of dispersion processes. In this study, we combined three complementary methods to investigate solute dispersivity at different length scales. The applied methods included 36-cm long column experiments, extremely large three-dimensional (3D) X-ray image-...
Article
Full-text available
It is widely accepted that metamorphism induces a remobilization of iron sulfides, sweeping away original ones while creating new ones. This paper analyzes size distributions of iron sulfides in several samples from the Caples and Torlesse terranes from the Otago Schist (New Zealand) using high-resolution X-ray computed tomography, which allows all...
Article
Air pollution is one of the main actors of stone deterioration. It influences not only the material itself but also prokaryotes colonizing rocks. Prokaryotes can affect rock substrates and biological colonization will most likely become relatively more important during the course of the 21st century. Therefore, it is necessary to understand the eff...
Article
Wettability is a key factor influencing multiphase flow in porous media. In addition to the average contact angle, the spatial distribution of contact angles throughout the porous medium is important, as it directly controls the connectivity of wetting and nonwetting phases. The controlling factors may not only relate to the surface chemistry of mi...
Article
Full-text available
Hypothesis Capillary-dominated multiphase flow in porous materials is strongly affected by the pore walls’ wettability. Recent micro-computed tomography (mCT) studies found unexpectedly wide contact angle distributions measured on static fluid distributions inside the pores. We hypothesize that analysis on time-resolved mCT data of fluid invasion e...
Preprint
Full-text available
Many natural building stones are altered when subjected to freeze-thaw (FT) cycles. On the one hand, the sensitivity of a material to FT damage has been quantified in the past by the existence of a material-specific critical water saturation. On the other hand, it was noticed that natural stones with a high volume of ink-bottle pores, normally hold...
Article
Full-text available
Freeze-thaw weathering is an important surface process and the complex underlying processes can be understood as an interplay between rock properties and its dynamic environment. Multiple researchers coming from different scientific disciplines have contributed to the present-day knowledge on the matter and misconceptions still prevail. In a changi...
Preprint
Capillary-dominated multiphase flow in porous materials is strongly affected by the pore walls’ wettability. Recent micro-computed tomography (mCT) studies show that contact angles can be measured inside the pores if the fluid distribution is static. However, this may not be directly relevant to dynamic fluid displacements. Here, we approximate rec...
Chapter
Superabsorbent Polymers (SAP) have been recently subject of investigation as smart admixtures for cement-based materials. The properties of these polymers enable their use for internal curing, increasing freeze/thaw resistance, boosting autogenous self-healing and providing a crack self-sealing effect in cementitious composites. Except for the earl...
Article
Full-text available
The behavior of a sandy soil in laboratory tests is highly influenced by the sedimentation technique. In this study, a calcareous sand from the reclamation site in Persian Gulf is used as the material to reconstruct laboratory scale samples with the air and water pluviation, moist and dry tamping and dry funnel deposition methods. The microstructur...
Article
Hypothesis: The wetting behaviour of the solid is a key property of a porous medium that controls hydraulic conductivity in multiphase flow. While many porous materials, such as hydrocarbon reservoir rocks, are initially hydrophilic and wetted by the aqueous phase, surface active components within the non-wetting phase can alter the wetting of the...
Article
Full-text available
Solute transport is important in a variety of applications regarding flow in porous media, such as contaminant groundwater remediation. Most recent experimental studies on this process focus on field‐scale or centimeter‐scale data. However, solute spreading and mixing are strongly influenced by pore‐scale heterogeneity. To study this, we developed...
Article
A newly discovered sedimentary accumulation of micrometeorites in the Sor Rondane Mountains of East Antarctica, close to the Wideroefjellet summit at similar to 2750 m above sea level, is characterized in this work. The focus here lies on 2099 melted cosmic spherules larger than 200 mu m, extracted from 3.2 kg of sampled sediment. Although the Wide...