
Matthias PahnTechnische Universität Kaiserslautern | TUK · Department of Civil Engineering
Matthias Pahn
Prof. Dr.-Ing.
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Publications (87)
Steigende Anforderungen an den Wärmeschutz und die Reduzierung von Transmissionswärmeverlusten an Gebäuden führen zu einem erhöhten Bedarf an energieeffizienten Dämmsystemen und Technologien für die Gebäudehülle. Im Rahmen dieses Beitrags werden mit dünnen Verbunddübeln neuartige Verbindungsmittel für ein effizientes vakuumgedämmtes Wandelement vor...
p>Glass-fibre reinforced polymer (GFRP) rebars are increasingly used in concrete as an alternative to conventional reinforcing steel, as corrosion issues can be excluded, and the application limits extended. Besides straight reinforcing bars bent rebars are used, e. g. as stirrups to absorb shear stresses. However, there is only a limited number of...
In the last years, the development of fibre reinforced polymers poses new challenges in the creation of new construction and in retrofitting of old buildings and in some cases also bridges. Advanced solutions for refurbishment and strengthening should be an alternative to demolishing old structures and building new ones. One of the established retr...
Durch die Vorgaben des Erneuerbare‐Energien‐Gesetzes wird Strom aus Erneuerbaren Energien vorrangig in das elektrische Netz eingespeist. Zur Vermeidung von Überlastungen im Stromnetz muss diese Einspeisung temporär reduziert werden. Die elektrische Energie, die in diesen Zeiträumen technisch erzeugt werden kann, aber nicht wird, wird als Ausfallarb...
Precast concrete sandwich panels (PCSPs) are known for their good thermal, acoustic and structural properties. Severe environmental demands can be met by PCSPs due to their use of highly thermally insulating materials and non-metallic connectors. One of the main issues limiting the wider use of sandwich walls in construction is their unknown fire r...
Ein klimaneutraler Gebäudebestand ist ein zentraler Baustein der weltweiten Klimaschutzziele. Neben der Reduktion des Wärmebedarfs durch Dämmung und effiziente Lüftung stellt die Nutzung von Erneuerbaren Energien (EE) den wichtigsten Ansatz dar. Zur Speicherung aktuell vorrangig Pufferspeicher, grundsätzlich kann aber in jeder Masse Wärme durch Änd...
Precast concrete sandwich panels are used to fulfil the rising thermal requirements. The sandwich walls consist of three layers, a facing, a thermal insulation layer, and a load bearing layer. The two outer layers are coupled by connectors made of glass-fibre reinforced polymer. A lack of knowledge about load-bearing behaviour prevents the removal...
The level of energy consumption in renovation activities of buildings has huge advantages over the demolition of old buildings and the construction of new structures. Such renovation activities are usually associated with the simultaneous strengthening of their elements, such as externally bonded carbon fibre reinforced polymer (CFRP) lamellas or s...
To reach international goals on climate protection, greenhouse gas emissions (GHG) of the building sector must be reduced significantly. Besides further insulation, renewable heat must be used, which require storage to utilise fluctuating heat generation. This storage can be gained by integrating thermal activations into solid external walls and th...
For more than 25 years sandwich connectors made from GFRP are known in different markets. In different parts of the world, national committees or authorities have defined different testing programs to assess the performance of such elements. Now in Europe an internationally counselled assessment document (EAD) is available and the first producers h...
In recent years, fibre-reinforced polymers (FRP), and glass-fibre reinforced polymers (GFRP) in particular, are advocated to be a promising alternative to traditional steel reinforcement in concrete structures to alleviate corrosion-related problems. Despite a large amount of studies on the short-term performance of FRP as non-prestressed reinforce...
Tensile testing seems to be a standard procedure for most engineering processes. There are standards for tensile testing for most materials including GFRP rebars. So it seems to be strange to see research relevance in such an well known and daily performed test. The authors will focus on the diameter influence and possible effects and influences of...
There is currently a lack of basic knowledge regarding the structural behavior of ultra-light mineral foams used in precast sandwich walls. To close this gap, this article discusses and analyzes experimental tests carried out to determine the adhesive shear strength and sliding friction between ultra-light mineral foam and standard concrete.
In recent years, green facades have become increasingly important in terms of sustainable urban development. In times of climate change and the increasing heating of cities, vertical greening offers a sensible option for regulating the urban climate. Greening of buildings in urban areas leads to a variety of positive effects. In addition to noise p...
Reinforced concrete sandwich facades are a proven solution for precast exterior walls. The reinforced concrete wall elements have a three-layer structure consisting of a facing layer, a thermal insulation layer and a load-bearing layer. Increasingly, the concrete facing layers are coupled using glass-fibre-reinforced plastic connectors. However, th...
Precast concrete sandwich panels are used to fulfil the rising thermal requirements. The sandwich walls consist of three layers, a facing, a thermal insulation layer, and a load-bearing layer. The two outer layers are coupled by connectors made of glass-fibre reinforced polymer. Current building approvals permit the removal of short-term and long-t...
The behaviour of façade anchors in high performance fiber reinforced concrete (HPFRC) has not been investigated in sufficient detail in recent years. The regulations in the European Technical Approvals also do not fully describe the load-bearing capacity of anchor systems. Due to the increase in the production of HPFRC elements, it is necessary to...
High performance fiber-reinforced concrete (HPFRC) has been frequently investigated in recent years. Plenty of studies have focused on different materials and types of fibers in combination with the concrete matrix. Experimental tests show that fiber dosage improves the energy absorption capacity of concrete and enhances the robustness of concrete...
The Federal Republic of Germany intends to realise a climate-neutral building stock by 2050. In order to achieve this goal, a high proportion of renewable energies in the heat energy consumption and energy-efficient buildings is required. Reducing heat losses through the building envelope is one option for achieving this goal. For this purpose, an...
As a result of growing energy requirements on buildings, multi-layer wall elements are being increasingly utilized. Existing systems that fulfil these requirements are precast fabricated wall elements. These elements have a three-layer structure consisting of a load-bearing layer, insulation core and a facing layer as protection against weather eff...
Currently, the lack of data on the long-term performance of FRP rebars, the international variation in ap-proaches and the FRP product diversity result in the absence of an international agreement in the methods of FRP durability testing. This paper aims to compare the current state of the art with the state of research, and to identify essential d...
de Bisherige Untersuchungen zu den Materialeigenschaften von UHPC konzentrieren sich vermehrt auf die Betondruckfestigkeit. Für unbewehrte, auf Biegung beanspruchte Bauteile wie Fassaden ist die Biegezugfestigkeit der maßgebende Bemessungsparameter. Mit Kenntnis über die Biegezugfestigkeit kann gleichzeitig die schwierig zu prüfende Zugfestigkeit e...
Multi-layer reinforced concrete wall panels consist of a supporting and facing wythe made of reinforced concrete as well as an internal insulation layer. The facing layer, which serves as a façade, is generally non-load-bearing and is used as a weather protection layer for thermal insulation and for the architectural design of the building. Despite...
The biaxial flexural strength of unreinforced concrete structures is hardly investigated because of a former lack of applications. Nowadays the applications, where a biaxial resistance is needed, increase. There are for example single unreinforced foundations, temporary shotcrete applications in tunnels and point supported slabs as facades. While t...
A cover for sandwich wall panels made of non-reinforced ultra-high performance concrete (UHPC).
Die Steigerung der Energieeffizienz von Ge-bäuden ist aufgrund von steigenden Ener-giepreisen, den knapper werdenden fossilen Energiereserven und des voranschreitenden Treibhauseffektes von zentraler Bedeutung. Die Minimierung von Transmissionswärme-verlusten und die solare Wärmespeicherung in Betontragstrukturen stellen wesentliche Lösungsansätze...
A micro-scale-based approach for the numerical analysis of cement-based materials, subjected to low-and high-cycle fatigue actions, is presented in this paper. The constitutive model is aimed at describing the evolving microstructural changes caused by cyclic loading protocols. More specifically, statistically representative microscopic geometries...
A micro‐scale‐based approach for the numerical analysis of cement‐based materials, subjected to low‐ and high‐cycle fatigue actions, is presented in this paper. The constitutive model is aimed at describing the evolving microstructural changes caused by cyclic loading protocols. The plastic‐damage‐based model is formulated combining the concepts of...
This paper provides preliminary results of a research study on the fatigue behavior of Ultra-High-Performance Concrete
(UHPC). Results of an experimental campaign, performed at the Department of Concrete Structures and Structural Engineering of the TU-Kaiserslautern, are firstly proposed. The heterogeneous meso-structure and material degradation of...
Fibre-reinforced polymers (FRP) have been used more and more in the building sector in the last decades. Especially glass-fibre reinforced polymer (GFRP) bars are a viable alternative to conventional reinforcing steel. Although an extensive research work of the short-term properties of FRP reinforcing materials has been made, the long-term behaviou...
Steigende bauphysikalische Anforderungen an die Außenhülle von Gebäuden bedingen zunehmend einen mehrschichtigen Wandaufbau. Betonfertigteile, die diese Anforderungen erfüllen, sind unter anderen Sandwichwände und kerngedämmte Elementwände. Die vorgefertigten Stahlbetonwandelemente weisen einen dreischichtigen Wandaufbau bestehend aus Vorsatzschale...
This paper provides experimental results on investigations for the validation of photogrammetric strain measurements of ultra‐high‐performance concrete (UHPC)‐prisms subjected to static and cyclic bending‐tensile stress. For this purpose, 4 static and 5 cyclic test series were performed. Damage progresses during loading are monitored by means of a...
As a result of growing energy requirements on buildings, multi-layer wall elements are being increasingly utilised. Existing systems that fulfil such requirements are element walls, precast walls and sandwich elements. Thermal insulation of large thickness is applied as a core insulation for such wall systems. Various types of connectors with diffe...
Precast concrete sandwich panels are used to fulfil the rising thermal requirements. The sandwich walls consist of three layers, a facing, a thermal insulation layer and a load-bearing layer. The two outer layers are coupled by connectors made of glass-fibre reinforced polymer. The connectors are loaded primarily in tension. Their failure mode unde...
Precast concrete sandwich panels are known for their inherently good thermal, acoustic and structural properties. When using glass fibre reinforced polymeric (GFRP) connectors coupling the concrete layers, excellent thermal properties and high structural stiffness can be achieved. However lack of knowledge on fire resistance of sandwich panels and...
This study investigates a test concept to derive a reliable long-term strength estimation of GFRP bars in concrete environment. Using the time to failure method, test results of straight GFRP bars with different diameters were compared. To represent closely the in service-conditions of concrete structures, the examined bars were subjected to a satu...
p>Poor durability of building structures leads to high repair costs. The durability of reinforced concrete structures is largely dependent on the corrosion resistance of the reinforcing steel. For applications which are highly endangered by corrosion, fibre-reinforced plastic (FRP) offer a solution. A basic prerequisite for the long-term functional...
The paper deals with the influence of cyclic loading on the bond between glass-fiber-reinforced polymer (GFRP) bars and concrete. The experimental study considers eccentric and centric pullout tests that vary by three different parameters: (1) concrete cover; (2) concrete strength; and (3) maximum load applied during cyclic loading. The results sho...
de Der Einsatz von Halbfertigteilen im Stahlbetonbau stellt eine wirtschaftliche Bauweise dar, welche sich durch einen schnellen Baufortschritt unter Einhaltung hoher Qualitätsansprüche auszeichnet. Ein Beispiel für Halbfertigteile sind Elementwände mit integriertem Dämmstoff. Bei solchen Wänden werden im Fertigteilwerk nur die äußeren Betonschalen...
This paper presents a multi-layer wall system where the facing layer of a core-insulated element wall system is substituted by the render system of an ETICS. In the stage of construction, spacers assume the function of formwork anchors in the thermal insulation material. This combines the advantages of a reduced facing layer thickness with the semi...
Der Großteil von Forschungsarbeiten zu den Materialeigenschaften von (U)HPC widmet sich der Druckfestigkeit. Die Zug-oder Biegezugfestigkeit ist nur selten im Fokus der Untersuchungen. Für unbewehrte, auf Biegung beanspruchte Bauteile wie zum Beispiel Fassadenplatten, ist die Biegezugfestigkeit der maßgebende Bemessungsparameter. Die Biegezugfestig...
The paper investigates the potentials of price based integration of renewable energies.
The thermo-mechanical behavior of sandwich panels was experimentally investigated. The panels featured two external concrete layers reinforced with glass fiber reinforced polymer rebars (GFRP) and an internal expanded polystyrene insulation layer. These are typical for low load bearing and thermally insulated panels in façade claddings. To assess t...
The paper investigates the potentials for storing excess electricity as heat in buffer storages, using heat pumps.
Precast energy-efficient concrete sandwich panels consist of two reinforced concrete layers and a core layer in between. The core layer, including thermal insulation material and mechanical connectors, transfers shear forces between the concrete wythes. Due to accuracy and simplicity of their assembly on site and their good thermal characteristics...
Fibre-reinforced polymers (FRP) have been used increasingly in the construction sector during last years. Offering high strength, low weight, non-corrosive, non-conductive and high durability, FRP materials are going to replace some traditional structural reinforcing techniques. Regarding the long-term-performance, however, research has shown that...
The Bahnheim quarter concept is intended to demonstrate cost-efficient, energy-efficient refurbishment options for 77 apartment buildings in a listed zone. The aim is to achieve the greatest possible energy savings while conserving resources, which can be realized and are in harmony with the preservation of historical monuments, building culture, e...
de Maßgebend für die wirtschaftliche Bemessung eines Stahlbetonsandwichelementes ist die realitätsnahe Ermittlung der Verformungen und der inneren Schnittgrößenverteilung. Entscheidend für diese Ermittlung sind unter anderem genaue Kenntnisse bezüglich der Materialeigenschaften des Dämmstoffes. Deshalb wurde das Materialverhalten für den eingesetzt...
The application of GFRP bars requires a familiar safety concept based on reliably determined long-term values. Therefore the effect of different exposure conditions and their synergism on mechanical and durability properties needs to be considered. This paper presents experimental and analytical investigations about the permanent tensile resistance...
Paper presents assessment of bond behaviour between GFRP bars and concrete, investigated through set of centric and eccentric pull-out specimens. Main parameters under investigation are 1) bar external surface, 2) concrete mechanical properties and 3) concrete cover. Corresponding tests with steel reinforcement are performed for comparison in some...
The book investigates several refurbishment strategies for multi family dwellings from the 1950s. Besides energetic and economic aspects also sociologic aspects are considered.
Large-size façade elements are mainly produced as non-load bearing precast concrete elements, which emerged together with the frame construction in the 1920s. Since 1960, such elements are also used as facing panel for sandwich walls, either with or without a subsequent layer of in-situ concrete. Both types of façade systems can be produced with a...
The thermo-mechanical behaviour of sandwich panels was experimentally investigated. The panels had two external concrete layers reinforced with GFRP rebars and an internal expanded polystyrene insulation layer. These are typical for low bearing panels in façade claddings. The heating condition was adjusted, that the internal GFRP rebars in one conc...
The experimental investigation is intended to study the influence of some parameters on the quasi-static and the fatigue behaviour of the bond between glass fibre reinforced plastic (GFRP) rebars and concrete. This is an important aspect in FRP reinforced concrete structural elements and of relevant importance in thin reinforced
concrete panels ext...
Precast multi-layered concrete sandwich panels gain popularity in construction of commercial as well as residential buildings. Such panels consists usually of two concrete layers and an insulation layer in between. Both concrete layers, reinforced commonly with steel reinforcement, are joint together by use of connectors. Replacement of steel reinf...
Storages for energy are needed hand-wringing, both for electricity and heat. But each of them comes with a price, losses from conversion and self-discharge. To reduce both storing energy, e.g. electric over capacities, as net energy brings benefits.
Heat can either be stored latent or by changing temperatures, using mass. In the context of building...
The experimental investigation deals with the quasi-static and fatigue behavior of the bond between GFRP (glass fibre reinforced polymer) rebars and concrete. Eccentric pull-out test set-up was adopted to measure the effect of concrete cover and concrete mechanical properties. For cycling tests, the ratio R of the maximum load in the cycle to the s...
The flexural tensile strength of structural elements made of concrete depends on the tensile strength and on the depth of the structural element. An increasing depth leads to a decreasing flexural tensile strength approaching to the tensile strength. This characteristic is called size effect. If the flexural tensile strength is tested on standard s...
The flexural tensile strength of structural elements made of unreinforced concrete depends on the tensile strength and on the depth of the structural element. An increasing depth leads to a decreasing flexural tensile strength approaching to the tensile strength. This characteristic is called size effect. If the flexural tensile strength is tested...
The paper investigates solid absorbers in external walls. To optimise the output of such, the influence of several parameters, e. g. colour or orientation, is investigated.
Innovative developments in the area of building materials enable construction of energy-efficient architectural concrete façades. Light and airy façades made of (ultra-)high performance concretes can be manufactured as facing shells or curtain façades for sandwich walls. Linear connections of glassfiber-reinforced plastic are used as anchorage elem...
The experimental investigation is focused on the thermo-mechanical behaviour of thin concrete panels reinforced with GFRP rebars. The considered thin panels (thickness of 4 cm) were exposed to increasing temperature and bending loading. These concrete elements are typical for low bearing function concrete layers in façade claddings. The influence o...
To use buildings as a thermal storage, their behavior must be investigated. Thus the storage behaviour of residential buildings in Germany for thermal energy. The buildings investigated are based on a comparison of building typologies. For heating the building the installed heating system was used. The investigation aims to describe the heating and...
This paper presents an experimental investigation dealing with the quasi-static behavior of the bond between GFRP (glass fibre reinforced polymer) rebars and concrete. The pull-out setup with eccentrically GFRP bar was adopted to measure the effect of three parameters: (1) thickness of the concrete cover, (2) diameter and surface of the bar and (3)...
With a new innovative experiment set-up it is possible to examine the multiaxial load bearing behaviour of whole facade systems
made of (U)HPC under realistic conditions. The 3D-deformation-analysis delivers deformation data, which can be
compared with FE-Models to check the plausibility. Few facades of artificial stone were tested. The failure loa...
New materials like (ultra)high-performance concrete and noncorrosive reinforcement
allow to reduce the thickness of facades without reducing the size of the elements.
So they can be used as curtain-wall facing or as facing for sandwich walls. To enable
a wise and material-saving calculation of such filigree facades, it is necessary to
check present...
New developments in the field of construction materials allow more and more filigree facades. They are produced with (U)HPC and internal reinforcement materials such as fibers or GFRP armoring bars. The high bending tensile strength of (U)HPC and the non-corrosive reinforcement allows to reduce the concrete cover and therefore a better use of the m...
The facade of a building represents its individual character and is the main design element of the architect. New developments of materials in the field of civil engineering like (ultra-) high-performance concrete, fibre-reinforced concrete and GFRP-reinforcement open new possibilities for filigree facades. The main purpose is the realization of ve...
In diesem Beitrag werden Verfahren zur Berechnungen von Trägern mit starrem oder elastischem Verbund sowie ohne Verbundwirkung behandelt. Die Anwendung von geschlossenen Lösungen für die exakte Berechnung des elastischen Verbundes ist unentbehrlich. Einige geschlossene Lösungen zur Bestimmung der Normalkraft und der Durchbiegung werden angegeben. A...
This paper presents experimental and analytical investigations about the creep behavior of Glass Fiber Reinforced Polymer (GFRP) connectors for multi-layered reinforced concrete walls (sandwich walls) under shear load. Ten double-shear push-out specimens with a free connector length of 50 mm was tested on shear to get the short-term value of the fa...
Für mehrschichtige Stahlbetonwandtafeln mit Verbindungsmitteln aus glasfaserverstärktem Kunststoff (GFK) sind neben den Nachweisen zur Tragfähigkeit auch Nachweise im Grenzzustand der Gebrauchstauglichkeit zu führen. Insbesondere bei hohen, schlanken Wandelementen ist das Verbundtragverhalten unter Einbeziehung der innen liegenden Wärmedämmschicht...
Since more than 100 years steel has been utilized as reinforcing material in concrete construction. Its high tensile strength, its ductile failure mode under tension and its thermal behaviour like concrete claim for a most appropriate combination of both materials. However, the low durability of steel constitutes a risk for the structural capacity...
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