Measurement Of Material Properties Research Articles

Validation of 3D thermal simulations of the Double C Block, a novel composite masonry unit, using in-situ U-value measurements

Energy efficient building envelopes, particularly innovative prefabricated building components, can significantly contribute to lower the building industry energy-related emissions. In this research the composite masonry unit Double C Block (DCB) is quantitatively tested by means of three-dimensional thermal simulation validated by in-situ U-value measurements carried out in both summer and winter conditions.The simulations were enhanced by the experimental measurement of the dry thermo-physical material properties (specific heat capacity, thermal conductivity, and density) in laboratory conditions for both concrete and polyurethane. The samples were extracted from real-scale DCB prototypes. Furthermore, site-specific boundary conditions of Malta — representative a case study of a Mediterranean climate − were utilised in the simulations. Both laboratory and in-situ assessments of thermal transmittance, or U-value, had their uncertainty specified as part of the calculations.The validation exercise was performed by means of hourly recorded surface temperature and the selected indices were the root mean square error and mean absolute error. Results showed that these indices were within the recommended accuracy thresholds during both winter and summer assessments. For the hourly-based heat flux measurements, the mean bias error and coefficient of variation of the root mean square error were found lower than values reported in literature, thus supporting the robustness of the overall simulation outputs. Hence the 3D CVM simulation was experimentally validated by in-situ assessments.The convergence value of the experimental U-value provided respectively 1.51 ± 0.20 W/m2K (winter) and 1.44 ± 0.19 W/m2K (summer). Then, the validated 3D CVM model was adapted to calculate the theoretical U-value of DCB, using monthly values of recorded surface temperatures obtained by the test cells (in both seasons). The predicted thermal transmittance was of 1.47 W/m2K, in both conditions, and this almost matches the above-mentioned experimental assessments and thresholds established in previous works.

Analysis of mechanical properties and stress distribution in self-healing microcapsules using micro-compressive test, nanoindentation test, and finite element analysis

Abstract This study analyzed self-healing microcapsules composed of melamine, urea, and formaldehyde (MUF). The thin shell’s mechanical properties were predicted using various techniques to gain a comprehensive understanding of their behavior. The compressive behavior of the microcapsules was assessed through micro-compression testing. The elastic modulus of the thin shell was precisely determined using nanoindentation, a method known for its accuracy in measuring material properties. Finite element analysis (FEA) was then applied, modeling the microcapsule between two plates and treating the core, which contains the healing agent, as an incompressible liquid. The mechanical properties of the thin shell, based on the elastic modulus derived from the nanoindentation test, were incorporated into the FEA, and the results were compared with those from the micro-compression test. Additionally, we analyzed the von Mises stress distribution to evaluate stress concentration within the spherical core–shell structure, ensuring the reliability of our conclusions. The test methods and analysis techniques presented in this study provide guidelines for improving the stiffness of MUF microcapsules. They can be further applied to predict the properties of materials with a spherical core–shell structure.

A study of the ultrasonic and audible frequency response of commercial loudspeakers for use as parametric acoustic arrays

Parametric acoustic loudspeakers (PAL), also known as parametric acoustic arrays (PAA), are speakers that use ultrasonic waves to generate directive audible sound. They emit an ultrasonic carrier modulated in amplitude by the desired audible signal, and due to non-linear propagation in air, this signal is reproduced in the audible range. Typical applications include audio reproduction for entertainment, but also active noise control and acoustic measurement of material properties. PAA typically consist of an array of piezoelectric transducers set on a surface. However, there are other speakers in the market that, due to their characteristics, could also achieve the PAL effect. This work examines the performance of commercial speakers when reproducing. First, the ultrasonic frequency response of each speaker is examined in free-field conditions using exponential sine sweeps (ESS). This enables searching for potential carrier frequencies to modulate the ESS in the ultrasonic range. The ESS are next modulated in the desired ultrasonic region and emitted through each speaker, obtaining their audible and ultrasonic impulse responses. The results show that some commercial speakers can also operate as PALs, which is interesting from an industrial point of view as it lowers costs and simplifies the assembly process.

Effects of grain size and stacking fault energy on twinning stresses of single-phase CrxMn20Fe20Co20Ni40-x high-entropy alloys

Deformation twinning was investigated in single-phase face-centered-cubic (FCC) high-entropy alloys of the CrxMn20Fe20Co20Ni40-x system (14 ≤ x ≤ 26 at.%). The intrinsic stacking fault energies (γisf) of these alloys varied systematically across this composition range, but other physical properties that have the potential of affecting deformation twinning remained constant allowing us to isolate the effects of γisf on twinning. Tensile tests were performed at 293 and 77 K, and the tests interrupted at several different strains to evaluate deformation-induced changes in microstructure by transmission electron microscopy. The critical stress above which deformation twinning occurs was thus determined. We also evaluated how grain size (19 ≤ d ≤ 237 µm) affects the yield stress (σy) and the uniaxial critical twinning stress (σtw), which allowed us to subtract the corresponding Hall-Petch contributions and compare our polycrystalline results with experimental and theoretical data reported for single crystals. Taking into account the critical resolved shear stresses for deformation twinning in our alloys (τtw) along with those of FCC pure metals and binary alloys reported in the literature, we derived the following relationship that rationalizes most of the experimental data: τtw = 10-3G + γisf/(3·bp), where G is the shear modulus and bp is the magnitude of the Burgers vector of a Shockley partial dislocation. This expression, involving only measurable material properties, can serve as a basis for the design and optimization of new HEAs with tunable twinning stresses and, in turn, exceptional strength-ductility combinations.

Photothermal measurement of material properties for translucent thermal barrier coatings

In this study, a photothermal nondestructive method was proposed to measure the material parameters of semi-transparent or translucent thermal barrier coatings (TBCs). We derived a theoretical model for the photothermal signal from a two-layer semi-infinite material system with a translucent first layer after a pulse laser excitation. Its solution was verified by numerical solution. A data regression algorithm based on a least-squares fitting was used for the determination of the material parameters in the translucent first layer material. To verify this new method, an experimental system was set up with a pulse laser for thermal excitation and an infrared camera for image acquisition of the thermal emission transient from several translucent EBPVD TBC samples. The predicted coating thickness is consistent with the measured value by an optical microscope. The predicted thermal conductivity and optical attenuation coefficients in the absorption and emission band are found to be in good agreement with reference values.

ETHOS: An automated framework to generate multi-fidelity constitutive data tables and propagate uncertainties to hydrodynamic simulations

Accurate constitutive data, such as equations of state and plasma transport coefficients, are necessary for reliable hydrodynamic simulations of plasma systems such as fusion targets, planets, and stars. Here, we develop a framework for automatically generating transport-coefficient tables using a parameterized model that incorporates data from both high-fidelity sources (e.g., density functional theory calculations and reference experiments) and lower-fidelity sources (e.g., average-atom and analytic models). The framework incorporates uncertainties from these multi-fidelity sources, generating ensembles of optimally diverse tables that are suitable for uncertainty quantification of hydrodynamic simulations. We illustrate the utility of the framework with magnetohydrodynamic simulations of magnetically launched flyer plates, which are used to measure material properties in pulsed-power experiments. We explore how changes in the uncertainties assigned to the multi-fidelity data sources propagate to changes in simulation outputs and find that our simulations are most sensitive to uncertainties near the melting transition. The presented framework enables computationally efficient uncertainty quantification that readily incorporates new high-fidelity measurements or calculations and identifies plasma regimes where additional data will have high impact.

Thermal buckling analysis of reinforced composite conical shells in acidic environments: Numerical and experimental investigation on the effects of nanoparticles

This study investigates the effects of acid penetration and temperature on the buckling behavior of conical composite shells, to enhance structural integrity and longevity in corrosive environments. The study explores the impact of acid exposure on thermal properties and examines the efficacy of incorporating nano-silica and nano-clay in preventing buckling. Additionally, it analyzes the influence of nanoparticles on the thermal, moisture, and mechanical properties of the composite material. Experimental assessments are conducted to measure material properties during exposure to a sulfuric acid solution, providing a comprehensive understanding of the material's behavior under extreme conditions. However, due to the complexity of investigating the combined effects of temperature, acid, and nanoparticles on composite shell buckling, a combined numerical and experimental approach is adopted to predict the critical buckling load. To this end, equations of conical shells under hygrothermal loading are derived, and the critical buckling load is determined through pre-buckling analysis. The Generalized Differential Quadrature (GDQ) method is employed to solve the hygrothermal buckling of the composite shell using experimentally obtained material properties. Comparative results are presented for different nanoparticles, shell geometries, and exposure times in acidic environments. The experiments reveal that adding nanoparticles enhances mechanical properties and reduces thermal and moisture expansion coefficients. Conversely, the acidic conditions deteriorate these properties. Numerical analysis demonstrates that incorporating nanoparticles significantly increases the critical buckling temperature, with nano-silica and nano-clay particles resulting in an 11.5 % and 34.2 % increase, respectively. However, acidic environments decrease the critical buckling temperature, with reductions of 32 % for unreinforced, 29 % for nano-silica reinforced, and 46 % for nano-clay reinforced composites after three months of exposure.

THE EFFECT OF FREQUENCY ON THE ELASTIC PROPERTIES OF MATERIALS

The elastic properties measurement of materials is important to determine their potential application in industries. Hence, the effect of frequency on the elastic properties is crucial in estimating the material's behavior with the change of frequency. Thus, this study was conducted to determine the effect of frequency on the elastic properties of materials. Five parameters of elastic materials were found in this study: bulk modulus, shear modulus, longitudinal modulus, Young's modulus, and lame constant. The elastic properties of three samples; stainless steel, aluminium and PMMA were measured for 2.25 MHz, 5 MHz and 10 MHz frequency. The method used is non-destructive testing using pulse-echo ultrasound techniques. The findings indicated that the longitudinal modulus, Young's modulus, shear modulus, bulk modulus, and lame constant of all samples are constant as the frequency increased from 2.25 MHz to 10 MHz. In conclusion, the elastic properties of a material are independent to the change of frequency.

Granule efficiency evaluation process using two-way CFD-DEM coupling analysis

Amino acid granulation using a fluidized bed is an important process that can improve the fluidity of powders and provide better process control. In this study, a granulation process evaluation procedure using numerical analysis is presented. Before analyzing the flow and particle behavior during the process, experiments and analyses such as pour angle of repose, drained angle of repose, and static angle of repose were performed to measure material properties and ensure the reliability of the numerical model. Material properties determined through experiments and numerical analyses were applied to an evaluation model of the granulation process. The granulation process is characterized by the interdependent behavior of a strong flow and large amounts of powder inside the equipment. A Computational Fluid Dynamics (CFD)-Discrete Element Model (DEM) coupled numerical model was presented for simulating particle and multiphase flow phenomena. Additionally, because there is a strong correlation between particle behavior and flow, a two-way coupling model was applied.The particle behavior characteristics are directly related to the granulation efficiency. Particle behavior was analyzed by setting four process conditions depending on the flow intensity. In this study, the concept of a dead zone was introduced to evaluate the kinetic performance of the particles under different process conditions. A dead zone is an area where the particles do not move actively and are unable to mix. The creation and size of the dead zone were compared based on the process conditions. Additionally, this study presents a procedure to evaluate the mass, volume, and size increase due to the granulation process based on the time spent in the granulation region. The granulation region is defined as the area in which the granulation of the particles is expected to proceed using the material sprayed from the nozzle. The granule quantity and uniformity were evaluated according to the process conditions. The granule amount refers to the mass and volume of individual particles that increase during the granulation process, and uniformity refers to the variation in granule amount between particles. The process efficiency can be evaluated as good when the granule amount of the work particles reaches the target value and is evenly distributed. Although the behavioral characteristics of the analyzed process did not represent all similar processes, it was confirmed that separate process conditions should be set according to the initial size distribution of the particles, target granule amount, and uniformity. Consequently, a series of processes was organized to obtain the properties of the target particles, effectively simulate the behavior inside the equipment, and reasonably determine the granulation region. Additionally, it presents a method to evaluate the amount and uniformity of granules rather than simply evaluating the time spent in the granulation region.

A mechanical characteristic capture method considering printing configurations for buildability modeling in concrete 3D printing

The structure failure modeling of 3D printing concrete (3DPC) during production is crucial for structure design, manufacturing process control and optimization. Serving as model inputs, the accuracy of 3DPC fresh material properties measurement highly affects the model prediction performance. The measured mechanical properties of freshly printed concrete strongly depend on the geometry, deformation and hardening process of used samples in testing. Herein, we propose an all-in-one method (AIOM) that synchronously considers these key factors (layer geometry, deformation, and hardening process) to more accurately capture the early-age mechanical performance distribution in printed structures. Different parametric-mechanical buckling models and two printable cementitious materials with distinct hardening characteristics (printable cement and printable geopolymer) were used to validate the performance of AIOM, with the traditional testing method, uniaxial unconfined compression test (UUCT), as the reference. Compared with UUCT, AIOM can improve the buildability prediction accuracy by 11.9 % to 50.8 % for different validation scenarios. This novel testing method for 3DPC fresh material properties contributes to improving the accuracy of 3DPC structure failure models, thereby facilitating a better production phase control for 3DPC.

High-Throughput Microstructural Characterization and Process Correlation Using Automated Electron Backscatter Diffraction

The need to optimize the processing conditions of additively manufactured (AM) metals and alloys has driven advances in throughput capabilities for material property measurements such as tensile strength or hardness. High-throughput (HT) characterization of AM metal microstructure has fallen significantly behind the pace of property measurements due to intrinsic bottlenecks associated with the artisan and labor-intensive preparation methods required to produce highly polished surfaces. This inequality in data throughput has led to a reliance on heuristics to connect process to structure or structure to properties for AM structural materials. In this study, we show a transformative approach to achieve laser powder bed fusion (LPBF) printing, HT preparation using dry electropolishing and HT electron backscatter diffraction (EBSD). This approach was used to construct a library of > 600 experimental EBSD sample sets spanning a diverse range of LPBF process conditions for AM Kovar. This vast library is far more expansive in parameter space than most state-of-the-art studies, yet it required only approximately 10 labor hours to acquire. Build geometries, surface preparation methods, and microscopy details, as well as the entire library of >600 EBSD data sets over the two sample design versions, have been shared with intent for the materials community to leverage the data and further advance the approach. Using this library, we investigated process–structure relationships and uncovered an unexpected, strong dependence of microstructure on location within the build, when varied, using otherwise identical laser parameters.

Ultrafast Heating-Induced Suppression of d-Band Dominance in the Electronic Excitation Spectrum of Cuprum.

The combination of isochoric heating of solids by free-electron lasers (FELs) and in situ diagnostics by X-ray Thomson scattering (XRTS) allows for measurements of material properties at warm dense matter (WDM) conditions relevant for astrophysics, inertial confinement fusion, and materials science. In the case of metals, the FEL beam pumps energy directly into electrons with the lattice structure of ions being nearly unaffected. This leads to a unique transient state that gives rise to a set of interesting physical effects, which can serve as a reliable testing platform for WDM theories. In this work, we present extensive linear-response time-dependent density functional theory (TDDFT) results for the electronic dynamic structure factor of isochorically heated copper with a face-centered cubic lattice. At ambient conditions, the plasmon is heavily damped due to the presence of d-band excitations, and its position is independent of the wavenumber. In contrast, the plasmon feature starts to dominate the excitation spectrum and has a Bohm-Gross-type plasmon dispersion for temperatures T ≥ 4 eV, where the quasi-free electrons in the interstitial region are in the WDM regime. In addition, we analyze the thermal changes in the d-band excitations and outline the possibility to use future XRTS measurements of isochorically heated copper as a controlled testbed for WDM theories.

A new method for predicting reference temperature of ferritic steel using finite element analysis and master curve method

Fracture toughness is an important parameter for measuring material properties in industry. In order to obtain data on the fracture toughness of a material it is often necessary to carry out a large number of fracture toughness experiments. The cost of the experiments is high and the experimental process is cumbersome. Moreover, in practice, there are often not a large number of materials that meet the requirements for the experiment. The relationship between different experimental ambient temperatures and fracture toughness can be determined by determining the reference temperature T0 in the master curve method. In this paper the load-displacement curves of the specimens are obtained using finite element analysis. Determine the J integrals corresponding to the initiating load Pint and the maximum load Pc on the load-displacement curve using the Load Slope Compliance Changing Rate method. Determine the reference temperature T0 in conjunction with the single temperature method. On the one hand, in order to validate the method, finite element analyses were performed on specimens of different thicknesses, temperatures, materials and types. This method was also applied to obtain fracture toughness data and to determine the reference temperature T0. On the other hand, combining the master curve method and combining the experimental data of 16MnDR, 16MnR and 20MnMoNi55 ferritic steels were verified. The experimental results show that the results predicted by this method are in good agreement with the actual results. However, it has a certain conservative type. It provides a good solution for practical engineering. The accuracy of fracture toughness and reference temperature of ferritic steels of different thicknesses can be verified by few experiments.

Experimental Guides for Metallic Materials：2. Measurement and Evaluation of Material Properties: 2-2 Structural Measurement and Analysis Using X-rays: 2-2-1 X-ray Production and Powder X-ray Diffraction

Experimental Guides for Metallic Materials：2. Measurement and Evaluation of Material Properties: 2-2 Structural Measurement and Analysis Using X-rays: 2-2-1 X-ray Production and Powder X-ray Diffraction

Characterization of defects in additively manufactured materials from mechanical properties

Minimization of defects in additively manufactured components is essential for material development and the determination of fabrication process windows. Here, a purely mechanical means of quantifying porosity in a material is developed based on the Mori–Tanaka mean field theory. The micromechanics based defect quantification approach developed here links the elastic properties of a material with the specific defect structures that must exist within it to obtain those properties. Laser powder bed fusion is used to fabricate aluminum 6061 with three different processing conditions to produce nominally identical samples with unique defect microstructures. Test samples are imaged with microcomputed X-ray tomography (μCT) and the images are classified with a machine learning method to identify the volume fraction of pores, solidification cracks, and the orientation distribution function of the solidification cracks. Tensile tests are then conducted in the z-axis and within the xy-plane to measure the respective elastic moduli and the Poisson’s ratio. These three commonly measured material properties are the only inputs to the new micromechanics based approach used to infer the same defect descriptors that were extracted from μCT. Excellent agreement is found between defect descriptors obtained with both methods, and quantities derived from the mechanical properties are found to carry substantially lower uncertainty. Full error propagation maps for the micromechanics based technique are calculated. Notably, defect descriptors from the micromechanics based approach are calculated from strain and load measurements, which are measured on much larger length scales than the defect size. This enables simple quantification of defects for materials containing small defects that are challenging to image.

Uni- and tri-axial tests and property characterization for thermomechanical effect on hydrated lime modified asphalt concrete

Permanent deformation, fatigue and thermal cracking are the three typical distresses of flexible pavement. Using hydrated lime (HL) into the conventional limestone mineral additive has been widely practiced, including in Europe, to improve the mechanical properties of hot mix asphalt (HMA) concrete and as the result the durability of the constructed pavement. Large number of experimental studies have been reported to find the optimum addition of HL for the improvement on HMA concrete mechanical properties, moisture susceptibility and fatigue resistance. Pavement in service is under complex thermomechanical stress-strain conditions due to coupled atmospheric and surrounding environment temperature variation and the traffic loading. To predict and analyse the performance of pavement structures the data only from uniaxial compressive test for the resilient modulus and permanent deformation would be not enough. However, so far, the data of HL modified HMA concrete under complex loading conditions are still not well informatively complete. To contribute new knowledge, this paper reports an experimental study of both uni- and tri-axial tests for the asphalt concrete using HL into mineral additive for the mixes designed for the applications of wearing, levelling, and base layers, respectively. All the tests were conducted under three controlled temperatures and four stress deviations. The test results have showed that, for all three types of mixes, the permanent deformation of the HL mixes is less than the ones of no HL addition. The degree of the improvement on permanent deformation resistance using HL is much pronounced at high stress deviation states. The results have also showed that the resilient modulus strongly depends on the temperature and stress deviation while the mixes of HL addition demonstrate higher rigidity. At last, mathematical characterization models have been proposed for the measured material properties. A numerical simulation case study has been performed to test and demonstrate the application of the proposed unified property model.

Experimental analysis on flow characteristics of particulate materials conveyed by airslides

Increasing demands on efficient airslides conveying in the fields of construction, agriculture, pharmacy and power require deep understanding of the flow characteristics of materials being conveyed. This study designs a full-scaled airslide test rig, in conjunction with an experimental method, to investigate the flow behaviour of two different materials, namely sand and flyash under vent and non-vent conditions. The flow modes of the sand and flyash are predicted based on the measured material properties and fluidisation. Furthermore, tests are conducted using the designed airslide, from which the flow is characterised by analysing the variations of the key parameters, including the mass flow rate, the superficial air velocity, the pressure inside the airslide and the flowing material bed height. The work shows the developed test rig and method are capable of characterising fluidised flow for airslide systems.

Modeling the cure shrinkage–induced warpage of epoxy molding compound

Product packaging processes often encounter issues, such as warping and deformation caused by the mismatch between the coefficients of thermal expansion of materials. Considerable amounts of epoxy molding compound (EMC) are used in packages. EMC exhibits viscoelastic properties and cure shrinkage, which can substantially affect the stress and warpage of packages. Mathematical models of cure shrinkage at isothermal and variable temperatures have not been comparatively discussed. Accordingly, this study aims to clarify the differences between the cure shrinkage during EMC curing estimated by the isothermal and modified two-domain Tait models. A fitting flow and calculation procedure for cure shrinkage was established to analyze the influence of these models on structural warpage. This study involved the experimental measurements of EMC material properties by using the cure reaction kinetics, isothermal and variable-temperature cure shrinkage, and generalized Maxwell models and degree of cure at gel point. Structural warpage was estimated by developing a process-oriented finite element method simulation and validating simulation results against experimental results. Analysis revealed good agreement between the warpage estimated by the two cure shrinkage models and experimental warpage. Compared with those of the other model, the results of the two-domain modified Tait model better matched the experimental results, with a deviation of approximately 1 %, because this model considered cure shrinkage that precisely corresponds to the actual process. Furthermore, the stress relaxation of viscoelastic behavior was validated through a parameterized post-curing process. Results indicated that although warpage occurrence reduced by extending the post-curing process time, it eventually converged to a certain value.

Design of a multi-modal sensor for the in-process measurement of material properties based on inductive spectroscopy

Ferromagnetic steel magnetic properties undergo isotropic and anisotropic changes during cold forming processes. Although their measurement provides an important basis for material property-controlled process control, it remains particularly challenging, as workpieces are subjected to several influencing effects, such as tilting and distance to the target. In this paper, we propose a robust contactless multi-modal sensor for the in-process measurement of material magnetic properties composed of a central excitation coil surrounded by eight receiving coils. The material magnetic permeability is measured based on a model-based evaluation of the central coil inductance spectrum compensating for the influence of the distance to the target. The sensor realizes a measurement of the magnetic anisotropy independently of the tilting effects based on an FFT-based analysis of the induced voltage in the peripheral coils. The sensor has been validated in a tensile test experiment on standard specimens. The measurement data of the tensile test reveal a systematic relation of permeability and magnetic anisotropy to the mechanical influences of stress and deformation. The measurements remained stable despite strong movements between the sensor and the target. A working distance increase of 80% resulted in variations of the magnetic permeability of only 3%. The observed changes in magnetic anisotropy are uncorrelated to tilting effects. Based on the investigation results a proposal for the design of an in-process measurement system is provided.

Evaluating the biocompatibility of ceramic materials for constructing artificial reefs

IntroductionCoastal ecosystems, including reefs, are becoming increasingly threatened as anthropogenic development continues to encroach on intertidal habitats with little initiative to establish ecologically considerate infrastructure. Submerging human-made, shelter-providing structures known as artificial reefs (AR) can contribute to the preservation of these ecosystems. ARs are historically used for promoting the abundance and biodiversity of marine species for aquaculture, conservation, and ecotourism; and are typically made of concretes or metal structures. An AR’s success correlates to its ability to establish a surface layer of microorganisms, such as microalgae and bacteria, known as a biofilm. The productivity of the biofilm can be influenced by material surface properties. It is hypothesized that material pH and porosity affect the rate of biofilm formation.MethodsHere - a range of concrete mixtures were cast and submerged in circulating seawater and mass per surface area of biofilm accumulation was measured to evaluate this theory. These mixtures included standard Portland Cement (PC), PC with admixtures of diatomaceous earth (PDC) and limestone (PLC), fine-aggregate high-performance concrete (DUC), and terra cotta (TER). ARs were manufactured as 38mm tall cylinders, 76mm in diameter, and submerged in circulating seawater to evaluate mass per surface area of biofilm accumulation.ResultsOur results indicate that biofilm formation is directly affected by surface porosity and less-so by pH, as determined by measuring material properties after submersion. We found that the PDC samples were most successful in forming a biofilm despite being more fragile than other concrete samples.DiscussionThis preliminary study provides insight into how different material properties influence the accumulation of biofilm as a starting point for designing ARs. Future work will investigate the long-term performance of such samples in relevant conditions.