Predicting micromechanical properties of cement paste from backscattered electron (BSE) images by computer vision

This paper employs computer vision techniques to predict the micromechanical properties (i.e., elastic modulus and hardness) of cement paste based on an input of Backscattered Electron (BSE) images. A dataset comprising 40,000 nanoindentation tests and 40,000 BSE micrographs was built by express nanoindentation test and Scanning Electron...

Correlation between the Mechanical Properties and the Structure of the Equine Osteochondral Interface During Maturation

The osteochondral interface is known to smoothly mitigate the stress concentration over the surface area of the subchondral bone, with a structural transition from the cartilage to bone. These sites in the body are exposed to high forces, which makes them prone to failure. To improve the repair strategies, a better understanding of the...

Micro-Mechanical Properties of Slag Rim Formed in Cement–Slag System Evaluated by Nanoindentation Combined with SEM

Slag rim mainly consists of secondary precipitations such as C–S–H gel phase and hydrotalcite-like phase, which originate from the hydration of slag. In this paper, the micro-mechanical properties of slag rim were characterized by nanoindentation in combination with SEM. It was found that, compared to the C–S–H gel phase, slag rim showed about a...

Effects of bacteria-embedded polylactic acid (PLA) capsules on fracture properties of strain hardening cementitious composite (SHCC)

Strain hardening cementitious composite (SHCC) is a special class of ultra-ductile material which has autogenous self-healing capability due to its intrinsic tight crack widths. To further improve its healing ability, healing agent (HA) can be incorporated in SHCC, enabling it also the autonomous self-healing mechanism. In this study, the...

In vivo, in situ and ex vivo comparison of porcine skin for microprojection array penetration depth, delivery efficiency and elastic modulus assessment

With the development of wearable technologies, the interfacial properties of skin and devices have become much more important. For research and development purposes, porcine skin is often used to evaluate device performance, but the differences between in vivo, in situ and ex vivo porcine skin mechanical properties can potentially misdirect...

EMC oxidation under high temperature aging

Epoxy molding compound (EMC) is widely used for encapsulating automotive electronics. Among all of the components of an electronic package, EMC is most exposed to the atmosphere, and thus undergoes aging. During high-temperature operation, EMC is oxidized, which alters its mechanical properties, and thus can affect the reliability of electronic...

The effect of SAP and SCM on microstructure development in early age fibre reinforced mortars

The use of Supplementary Cementitious Materials (SCMs) in concrete manufacture has significantly increased in the last decades mainly due to their sustainability benefits. Polymeric Fibres (PF) are commonly used in concrete in order to enhance adhesive and frictional bond with a cementitious matrix and improve mechanical properties. Despite...

Investigation of the elastic modulus of polymer sleepers under a quasistatic and cyclic loading

In ballasted track, the wheel load is transmitted to the subgrade via sleepers commonly made of impregnated wood, prestressed concrete, steel or recently developed polymer sleepers. Mentioned material types of sleepers are characterized by different elastic moduli being a key parameter in any numerical model. Hence, this paper aims to...

3D imaging and micro-structural characterization of reinforced concrete structures naturally-deteriorated due to corrosion

In this study, a three-scale characterization of eight 20-years-old reinforced concrete specimens naturally deteriorated due to chloride-induced corrosion was carried out. The main aim of this research was to investigate some relevant parameters to accurately model corrosion of reinforced concrete structures, such as which are the locations...

Multi-material 3D printed mechanical metamaterials: Rational design of elastic properties through spatial distribution of hard and soft phases

Up until recently, the rational design of mechanical metamaterials has usually involved devising geometrical arrangements of micro-architectures that deliver unusual properties on the macro-scale. A less explored route to rational design is spatially distributing materials with different properties within lattice structures to achieve the...

Effect of biofilm structural deformation on hydraulic resistance during ultrafiltration: A numerical and experimental study

Biofilm formation in membrane systems negatively impacts the filtration system performances. This study evaluated how biofilm compression driven by permeate flow increases the hydraulic resistance and leads to reduction in permeate flux. We analysed the effect of biofilm compression on hydraulic resistance and permeate flux through...

Determination of mechanical properties of biofilms by modelling the deformation measured using optical coherence tomography

The advantage of using non-invasive imaging such as optical coherence tomography (OCT) to asses material properties from deformed biofilm geometries can be compromised by the assumptions made on fluid forces acting on the biofilm. This study developed a method for the determination of elastic properties of biofilms by modelling the biofilm...

Optimization of a geopolymer mixture for a reinforced cantilever concrete bench: Additional thesis project

Traditional Ordinary Portland cement (OPC)-based concrete consumes large quantities of natural resources for its production, which is<br/>highly energy intensive and has high CO2 emission. Therefore, development of the geopolymer concrete, based on use of industrial byproducts,<br/>can provide an environmentally friendly and low-carbon...

Elastic modulus of the alkali-silica reaction rim in a simplified calcium-alkali-silicate system determined by nano-indentation

This work aims at providing a better understanding of the mechanical properties of the reaction rim in the alkali-silica reaction. The elastic modulus of the calcium alkali silicate constituting the reaction rim, which is formed at the interface between alkali silicate and Ca(OH)2 in a chemically-idealized system of the alkali-silica reaction...

AC Electrical Breakdown Strength of Solid Solid Interfaces: A study about the effect of elasticity, pressure and interface conditions

In several electrical insulation components, such as cable connectors, joints and penetrators, various solid insulating materials are usually brought in contact, forming interfaces. The dielectric strength of these solid$|$solid interfaces is critical for the strength of the overall system. Especially in cases that the applied field has a...

Molecular and macroscopic orientational order in aramid solutions: A model to explain the influence of some spinning parameters on the modulus of aramid yarns

Compressive failure in high modulus polymeric fibers