Andreas Jäger

• Business Development Manager at Wienerberger AG

Fire tests on masonry are one of the most expensive experiments in developing new vertically perforated clay block geometries. Numerical simulations might be a reasonable substitute for such experiments, leading to a significant cost reduction in the development phase. However, the prediction of such tests with numerical modelling concepts is chall...

Given the popularity of fired clay bricks in increasingly taller buildings, as well as the large variety of raw materials, additives, tempers, and production technology, microstructure-based modeling of the brick strength is essential. This paper aims at linking the microstructural features of bricks, i.e. the volume, shape, and size of mineral pha...

Der jahrtausendealte bewährte Baustoff Ziegel hat sich im vergangenen Jahrhundert beeindruckend weiterentwickelt. War es früher der einfache, flexible kleinformatige Ziegel, werden aktuell Mauerwerkssysteme verwendet, die auf die speziellen Anforderungen der Gebäude‐ und Wandtypen optimiert sind. In diesem Beitrag wird einerseits diese Entwicklung...

Quantification of elastic stiffness and thermal conductivity of fired clay bricks is still often limited to empirical rules and laboratory testing, which becomes progressively more challenging given the large variety of raw materials used to optimize the properties of modern brick products. Applying a continuum micromechanics multiscale approach, w...

Zyklische Schubversuche sind eine gängige Methode, um die Tragfähigkeit und das Verformungsverhalten von Wänden bei dynamischen Belastungen in horizontaler Richtung, wie sie zum Beispiel bei Erdbeben auftreten, zu beurteilen. In der vorliegenden Arbeit werden zyklische Schubversuche an 36 Wänden aus verschiedenen Mauerwerksarten beschrieben, die Te...

Optimizing thermal and mechanical properties of clay block masonry requires detailed knowledge on the microstructure of fired clays. We here identify the macro- and microporosity stemming from the use of three different pore-forming agents (expanded polystyrene, sawdust, and paper sludge) in different concentrations. Micro-CT measurements provided...

en Before the introduction of EC 6, simple codes permitted masonry to be designed manually. The simplified procedure according to EN 1996‐3 still allows manual design, but its application is restricted. Therefore, a more laborious design according to EN 1996‐1‐1 is often required. This article presents a newly developed software tool, which facilit...

In the scope of the transnational access activities within the 7th European Framework Program (FP7), SERIES (Seismic Engineering Research Infrastructures for European Synergies), Wienerberger AG and a group of European experts evaluated the seismic behaviour of full-scale prototypes of modern unreinforced thermal insulation clay block masonry build...

In the scope of the transnational access activities of the European research project SERIES, the Laboratório Nacional de Engenharia Civil (LNEC) has provided access to its 3-D shaking table to the international construction company Wienerberger AG and to a group of European experts, in order to perform full-scale seismic tests on an industrial solu...

In the scope of the transnational access activities of the European research project SERIES, the Laboratório Nacional de Engenharia Civil (LNEC) has provided access to its 3D shaking table to the international construction company Wienerberger AG and to a group of European experts, in order to perform full-scale seismic tests on an industrial solut...

Im Rahmen des Europäischen Forschungsprojekts SERIES (Seismic Engineering Research Infrastructures for European Synergies) wurden unter der Leitung von Wienerberger und in Zusammenarbeit mit einem internationalen Forscherteam Rütteltischversuche an Mauerwerksgebäuden aus mit Dämmstoff gefüllten Ziegeln durchgeführt. Das Verhalten von dämmstoffgefül...

In the scope of the transnational access activities of the European research project SERIES, the Laboratório Nacional de Engenharia Civil (LNEC) has provided access to its 3D shaking table to the international construction company Wienerberger AG and to a group of European experts, in order to perform full-scale seismic tests on an industrial solut...

Jährlich verunglücken in den Ländern der Europäischen Union 3600 Menschen tödlich bei Brandunfällen. Mehr als ein Drittel der Brände passieren in Gebäuden. Baukonstruktionen mit hohem Brandwiderstand und nicht brennbare Bauprodukte wie der Ziegel können also einen wesentlichen Beitrag für mehr Sicherheit in Gebäuden leisten. Andererseits fordern Vo...

This paper covers the development and validation of a multiscale homogenization model for linear viscoelastic properties of wood. Starting point is the intrinsic structural hierarchy of wood, which is accounted for by several homogenization steps. Using the correspondence principle, an existing homogenization model for the prediction of elastic pro...

A new procedure to characterize the full set of elastic constants of wood cell walls was developed. For the first time, not only the longitudinal modulus, but also the transverse- and the shear modulus were determined in one experimental setup at micron scale. For this purpose, nanoindentation experiments were performed at variable angles between t...

Es wurde eine neuartige Mauerwerkskonstruktion von Wienerberger entwickelt, die auf der Verklebung von Planziegeln mit einem Einkomponenten‐Polyurethankleber basiert. Dieser Mauerwerkskleber wird direkt auf die Lagerfugen der Planziegel aufgebracht und stellt nach Aushärtung eine dauerhafte und feste Verbindung unter den Ziegeln her. Die Vorteile d...

Nanoindentation is a well known tool for identification of mechanical properties at the micrometer scale of materials. When applied to study wood cell walls the commonly used isotropic indentation theory is not applicable. In this study, anisotropic nanoindentation theory was employed for analyzing nanoindentation test results on wood cell walls. T...

Red oak wood (Quercus rubra L.) samples were submitted to an enzymatic treatment with a commercial mixture of hemicellulases aiming at the selective depolymerization and removal of the hemicelluloses. Mechanical properties of treated samples were characterized and compared with untreated samples at two hierarchical levels. At the macro-level, tensi...

In the last years Nanoindentation (NI) has become a frequently used tool in material science. Since Wimmer et al. (1997) introduced NI in wood science for the characterisation of micro-mechanical properties, the validity of the obtained data and their significance is a matter of debate. As NI theory was initially developed exclusively for homogenou...

Spherical indentation is commonly used to study the elastic and visco-elastic response of materials at different length scales. However, depending on the strength properties of the investigated material and the geometric properties, such as sphere radius and penetration depth, plastic material response might occur, making parameter identification f...

Mechanics of Materials and Structures has become a popular new name of former Institutes for Strength of Materials and/or Structural Analysis at European Universities of Technology. This designation stands for a scientific program aimed at a symbiosis of material and structural mechanics. The adjective “computational” refers to the algorithmic comp...

  Motivated by recent progress in viscoelastic indentation analysis, the identification of viscoelastic properties from materials exhibiting elastic, viscous and plastic material behaviour by means of nanoindentation is dealt with in this paper. Based on existing solutions for pure viscoelastic material behaviour, two methods allowing us to conside...

A method for the identification of model parameters describing the time-dependent material behavior by means of cyclic nanoindentation is presented. The complex shear modulus of the material sample is determined from the prescribed amplitude in the load history, the measured amplitude in the penetration history. and the phase shift between the peak...

Rheological models are used for the description of viscoelastic properties. Such investigations are mostly based on experiments with a torsional rheometer, i.e. a Rubber Process Analyzer. The results of such experiments are storage and loss modulus, which depend on the applied angular frequency. The investigations were performed with rubber compoun...

Motivated by recent progress in viscoelastic indentation analysis, the identification of viscoelastic properties from nanoindentation test data taking the real tip geometry into account is presented in this paper. Based on the elastic solution of the indentation problem, the corresponding viscoelastic solution is obtained by the application of the...

In order to understand the complex thermo-rheological behavior of asphalt, stemming from the viscoelastic nature of bitumen, the nanoindentation (NI) technique is employed. Hereby, the load history applied onto the indenter tip is characterized by a loading, holding, and unloading phase. As regards the identification of viscoelastic properties, a r...

In order to cover the effect of styrene-butadiene-styrene (SBS) modification on the characteristics of bitumen, two types of bitumen, one plain bitumen, and one polymer modified bitumen produced with the plain bitumen as base material were characterized in terms of chemical composition, microstructure, micromechanical properties, and thermoanalytic...

Recent progress in both finer-scale experimentation (atomic force microscopy, nanoindentation (NI),...) and theoretical and numerical upscaling schemes provides the basis for the development of so-called multiscale models, taking finer scales of observation into account. Hereby, chemical, physical, and mechanical processes taking place at finer sca...

The mechanical properties of both the adhesive and interphase cell walls in wood adhesive bonds were determined by nanoindentation. Seven different polymers used frequently as adhesives and/ or matrix polymers in wood, wood composites, and natural fibre reinforced composites were studied by nanoindentation (Konnerth et. al [1]) and compared with re...

Seven different polymers used frequently as adhesives and/or matrix polymers in wood, wood composites, and natural fiber-reinforced composites were studied by uniaxial tensile tests and nanoindentation. It was shown that the elastic modulus, the hardness, the creep factor, and the elastic-, plastic-, and viscoelastic work of indentation of the seve...

The dimensioning of injection heads for the extrusion of rubber profiles is exclusively based on empiric knowledge of the non-linear flow behaviour of elastomers. The swell- ing of the extrudate when emerging from a capillary is typical for viscoelastic fluids, such as polymers and rub- ber blends, respectively. Therefore, the experimental in- vest...

Motivated by recent progress in both experimentation and the micromechanical description of the behavior of multi-composed materials, a multiscale model for asphalt is currently developed at the Christian Doppler laboratory for “Performance-Based Optimization of Flexible Pavements” at Vienna University of Technology. This model allows us to relate...

Accounting for the large variation of asphalt mixes, resulting from variations of constituents and composition, and from the allowance of additives, a multiscale model for asphalt is currently developed at the Christian Doppler Laboratory for “Performance-based optimization of flexible road pavements”. The multiscale concept allows to relate macros...

The identification of material phases at the so called bitumen-scale in context of multiscale modeling of asphalt is presented. For this purpose, atomic force microscopy (AFM), providing insight into the surface topography and mechanical properties, is applied to different types of bitumen. Based on the obtained AFM results, four different material...

Macroscopic material properties of asphalt are related to finer-scale information by means of a multi-scale model consisting of five observation scales. Having identified the different constituents (material phases) and their assemblages at the scales introduced within the multi-scale model, we present recent results on up-scaling information from...