Harald Garrecht

• Prof. Dr.-Ing.
• Director at University of Stuttgart

The results of research conducted over the past few decades on concrete mixtures have led to a significant increase in the compressive strength of concrete. These higher-performance concretes allow slimmer constructions, but they are also more vibration-prone as a consequence. Consequently, the fatigue behaviour of high-performance concrete is beco...

Both in research and in the construction industry, there are various simulation methods and programmes for thermal and energy analysis and assessment in the building industry. Often only one method is used without considering the useful addition of other methods. This is also due to the lack of compatibility between programmes. The research p...

Natural Ventilation Effectiveness (NVE) is a performance metric that quantifies when outdoor airflows can be used as a cooling strategy to achieve indoor thermal comfort. Based on standard ventilation threshold and building energy simulation (BES) models, the NVE relates available and required airflows to quantify the usefulness of natural ventilat...

Today, it is important to realise buildings and civil engineering structures as ecologically and sustainably as possible. The production of cement and aggregates has very high CO2 emissions, which must be reduced in the future. There are many ways to achieve this in the coming years. On the one hand, the durability of buildings must be increased. O...

Fortunately, increasingly high-performance concretes (HPC) have been developed in recent decades. This allows constructors and architects to build ever lighter and slimmer concrete structures. As a result, the heavy and massive construction method is coming closer to the slim and elegant construction method of steel construction. This can make the...

To achieve Germany's 2045 goal of climate-neutral building stock, the integration of renewable energies in retrofitting is necessary. The project ‘CO2-neutrales Welterbe Speicherstadt Hamburg’, situated in the historic warehouse district, focuses on the sustainable heat supply in listed buildings. The project consists of two main approaches: a prac...

The research focuses on ultra-lightweight foam concrete with a dry density below 200 kg/m³, primarily used as insulation material. Factors that may affect material properties are categorized into mixing techniques and material composition, and experimental investigations were conducted on the impact of these factors on the rheological properties of...

In the restoration or rehabilitation of traditional buildings, compatible materials with known characteristics must be used. However, the existing literature lacks comprehensive studies on the characterisation of Persian mud–straw plaster, focusing primarily on Persian adobe. Moreover, previous research on Persian adobe has primarily employed XRF a...

To achieve Germany's 2045 climate-neutral building stock goal, the integration of renewable energies in retrofitting is necessary. The CO2-neutral Speicherstadt Hamburg project in the historic warehouse district focuses on sustainable heat supply in listed buildings. The project consists of two main approaches: a practical approach combining histor...

Kurzfassung In zahlreichen Forschungsvorhaben gibt es aktuell Bestrebungen die bisherigen Bauweisen ökologischer zu gestalten. Da Beton der meistverwendete Baustoff in unserer gebauten Umwelt ist, gilt ihm und seinen Bestandteilen besonderer Beachtung. So ist der Einfluss von RC‐Gesteinskörnungen in hochfesten Betonen noch nicht ausreichend erforsc...

Economic efficiency of road maintenance is an important topic in science and practice. Especially maintenance programs and their technical and economic efficiency is an important aspect. A decisive parameter for systematic road maintenance is the possibility of prediction of deterioration processes, which depends on basic material or pavement prop...

Wind pressure coefficients () represent a critical boundary condition when assessing multizone naturally ventilation buildings with airflow network (AFN) models. This simulation workflow uses OpenFOAM through a 3D parametric modeling platform. The approach is used to calculate surface-averaged `s over an entire façade and an opening. The outcomes o...

The increasing demand for civil infrastructures, the aging of existing assets, and the strengthening of safety and liability laws have led to the inclusion of structural health monitoring (SHM) techniques into the structural management process. With the latest developments in the sensors field and computational power, real-scale SHM systems’ deploy...

To deploy an accurate safety-relevant structural health monitoring, one must assure the utmost care and in-depth knowledge of the monitored structure, which may present challenges such as the reliability to detect unexpected anomalies due to the failure of a component, the correct setting of thresholds and triggers to discern changes due to environ...

Drei Fachtagungen bieten die EIPOS-Sachverständigentage 2022 an. "Holzbau & Holzschutz" fokussiert den Brandschutz, den konstruktiven Holzschutz und historische Dachtragwerke. Auf der Tagung "Sachverstand am Bau" werden unter anderem Rissschäden, Spritzwasser an Fassaden, Lüftungskonzepte sowie Innovationen im Baustoffbereich diskutiert. Themen der...

Mängel, Schäden, Prävention – um diese drei zentralen Begriffe der Sanierungspraxis drehen sich die 32. Hanseatischen Sanierungstage. 22 Referenten zeigen in ihren Beiträgen Schadensursachen auf, beschreiben Präventionsmaßnahmen und stellen besonders gelungene Sanierungsprojekte vor. Eine Hauptschadensursache sind Wasser und Feuchte. Oftmals werden...

High-performance concrete (HPC) is a topic of current research and construction projects, due to its outstanding compressive strength and durability. In particular, its behaviour under high-cycle fatigue loading is the focus of current investigations, to further pave the way to highly challenging long-lasting constructions; e.g., bridges or offshor...

Due to research activities on the topic of concrete mixtures during the last decades, concrete compres-sive strength has increased significantly. At the same time, the lifespan of concrete structures has continuously extended. Therefore, the fatigue behaviour of high-performance concrete (HPC) becomes more important with in regard of service life d...

Performance-based design using computational and parametric optimization is an effective strategy to solve the multiobjective problems typical of building design. In this sense, this study investigates the developing process of parametric modeling and optimization of a naturally ventilated house located in a region with well-defined seasons. Its pu...

Highly efficient insulating systems help reduce heat losses and promote building energy efficiency due to their very low thermal conductivity. However, when applied to outdoor surfaces, climate conditions exposure might deteriorate the material's properties, compromising the building's energy performance over its lifetime. In the framework of a Eur...

The ability to track the structural condition of existing structures is one of the main concerns of bridge owners and operators. In the context of bridge maintenance programs, visual inspection predominates nowadays as the primary source of information. Yet, visual inspections alone are insufficient to satisfy the current needs for safety assessmen...

Predicting building air change rates is a challenge for designers seeking to deal with natural ventilation, a more and more popular passive strategy. Among the methods available for this task, computational fluid dynamics (CFD) appears the most compelling, in ascending use. However, CFD simulations require a range of settings and skills that inhibi...

The enhancement of new quality criteria in highway construction is a key aspect to improving the construction process and lifetime of road. In particular, mobile laser scanning systems are nowadays able to provide realistic 3D elevation profiles of a road to detect anomalies. In this context, this study utilizes a high-accuracy high-speed mobile ma...

The data set compiled in this file refers to the Multizone EnergyPlus model, used in the investigations of the research article entitled "Natural ventilation potential from weather analyses and building simulation". The technical information regarding the model has been grouped into tables, which include: the general simulation settings, the proper...

Many concrete technologists are looking for a solution to replace Fly Ashes that would be unavailable in a few years as an element that occurs as a major component of many types of concrete. The importance of such component is clear - it saves cement and reduces the amount of CO2 in the atmosphere that occurs during cement production. Wood Ashes fr...

Über den aktuellen Wissensstand im Bereich Denkmalpflege, Sanierungspraxis und Bautenschutz berichten auf der jährlich stattfindenden dreitägigen Fachtagung Bauexperten, Unternehmer, Bauleiter und Sachverständige. Der Tagungsband bietet Einblicke in das weite Spektrum des Bauens im Bestand. Die Beiträge erörtern anhand beeindruckender Praxisbeispie...

A practical way to reduce energy consumption is to use traditional construction methods and materials. Persian architecture has a long history of constructing energy-efficient and comfortable buildings for the human and has created sustainable cities. Hygrothermal analysis of a building in Yazd, a city in the hot-dry region of Iran, was performed,...

for download please visit: https://authors.elsevier.com/c/1c3Ms_8dCXj1Jc Naturally ventilated buildings' performance relies on their design and climatic conditions. Thus, when investigating the natural ventilation potential (NVP), the meteorological data plays a crucial role. This study discusses NVP assessment under two approaches: a general ev...

Naturally ventilated buildings have been worldwide increasingly welcomed, given the current global awareness toward environmental sustainability, indoor health-quality and renewable energy. As Natural Ventilation (NV) performance relies on building design and interaction with the local environment, its potential benefits are not always easy to take...

This paper presents the results of an interlaboratory study of the rheological properties of cement paste and ultrasound gel as reference substance. The goal was to quantify the comparability and reproducibility of measurements of the Bingham parameters yield stress and plastic viscosity when measured on one specific paste composition and one parti...

Determining the exact rheological properties of cementitious materials in fundamental units is a crucial step in concrete science. It is undisputed that before measuring rheological properties in concrete rheometers, it is necessary to pre-shear the fresh mortar or concrete. Due to the migration of the coarse particles into areas with lower shear s...

Concrete chemistry is an integral component in the development of eco-concretes, easily compactible concretes, high-strength and very durable concretes. It is always necessary to adapt the fresh and hardened concrete properties to the respective application. In order to be able to develop a specific mix design, two essential requirements have to be...

Der Beitrag stellt ? einleitend für eine Reihe weiterer folgender Beiträge ? die Rahmenbedingungen und Ziele eines Verbundvorhabens vor, welches von der Universität Stuttgart, der Margarethe-Krupp-Stiftung für Wohnungsfürsorge, vom Gas- und Wärmeinstitut Essen sowie der RWTH Aachen durchgeführt wurde. Dabei werden am Beispiel der Essener Wohnsiedlu...

de Die deutsche Bundesfernstraßeninfrastruktur umfasst rund 13 000 km Bundesautobahnen und 39 000 km Bundesstraßen. Große Teile des Straßenbestands erfordern die gänzliche Erneuerung. Bei Bundesautobahnen kommt zunehmend die Betonbauweise zum Einsatz. Entsprechend widmet sich der Beitrag einem Teilaspekt des vom Ministerium für Verkehr und digitale...

The study investigates the U-value development of two different insulation render systems on two different base walls in the context of a large-scale artificial weathering laboratory test, to assess the durability of the render systems. In total four wall partitions of different composition were investigated. A particular focus is the improvement o...

Due to research activities on the topic of concrete mixtures during the last decades concrete compressive strength could be increased significantly. At the same time the lifespan of concrete structures has been continuously extended. Therefore, the fatigue behavior of modern High Performance Concrete (HPC) becomes more important with respect to ser...

Modern concretes are characterised not only by rising demands on properties but also by increasingly complex compositions. With sophisticated formworks and dense reinforcements, the trend in concrete technology continues towards to self-compacting and easily-compacting concretes. The use of highly effective superplasticizers makes these concretes n...

The main objective of the environmental protection is the sustainable energy supply of residential areas. This is made possible by networking several buildings in the same district in order to produce a sustainable, efficient and self-sufficient supply of electrical and thermal energy. The second elementary topic is the conversion from combustion e...

In the paper, the performance of two phase change materials (PCMs) is evaluated numerically and experimentally. Technical requirements, size limitations and time response of the PCM present crucial boundary conditions when choosing the right material and storage type in the residential sector. The latent heat thermal energy storage system analysed...

Since energy-efficient construction is of great importance, new construction and rehabilitation methods concerning this topic will always be researched. Among these are of course, methods that benefit from solar energy. As part of the BMWi project (Federal Ministry of Economics and Energy) “SWIVT” several options of the energy consumption of reside...

Structural health monitoring (SHM) of civil engineering structures has been widely developed to increase safety and to provide cost-effective maintenance programmes. Although the current approaches of SHM systems using traditional single-point sensors – such as electric strain sensors, accelerometers and global positioning system-based sensors – ha...

Non-destructive measures regarding building dampness assessment plays a vital role within the constructions health evaluation. In this sense, this research investigates the relationship between impedance measurements and moisture content inside building porous materials. 1D simulations involving computational modelling of coupled heat and moisture...

In building simulations for hydrothermal evaluation there are many uncertainties related to the materials properties, to the initial and boundary conditions and to the calculation methods used for the models. The aim of this paper is to perform a series of hydrothermal simulation with two disseminated solvers: WUFI Pro 4.2 and DELPHIN (Version 5),...

Concerns related to buildings' green-house emissions in recent years lead to the increase of architectural adaptation to local environment. While passive conditioning strategies emphasising natural ventilation are common alternatives to achieve indoor comfort in hot and humid climate, they are not widely used in temperate climates. In this context,...

The fatigue behaviour of modern High Performance Concrete (HPC) depends on many factors. Amplitude, load level and frequency play a significant role regarding the number of cycles to failure under compressive cyclic loading. In addition humidity and temperature are influencing the fatigue life. Concrete under cyclic loading heats up due to its dens...

Die Celler Schlosskapelle ist ein Gesamtkunstwerk von europäischem Rang. Die Übernutzung durch starken Besucherverkehr führte in den 1980er Jahren zu Schäden. Die öffentliche Zugänglichkeit wird deshalb seit 1995 auf einen verglasten Besucherraum beschränkt. Die Übernutzung und Beschädigung bis 1995 waren aber schon nach 10 bis 20 Jahren nahezu in...

Der Beitrag berichtet von den am Schloss Erxleben durchgeführten Maßnahmen zur Sanierung geschädigter Holzbauteile mittels Heißluftverfahren (nach DIN 68800-4 und DIN CEN/TR 15003) unter Einbeziehung der Mauerwerkswände. Ziel des zugrunde liegenden Forschungsprojektes war die ressourcenschonende Ertüchtigung der historischen Bausubstanz mit messtec...

Das Korrosionsverhalten des austenitischen nichtrostenden Stahls 1.4404 und des chromhaltigen hochwarmfesten Stahls 1.4903/T91 wurde in nitrathaltiger Salzschmelze (60 % NaNO3-40 % KNO3) mit verschiedenen Chloridgehalten in Auslagerungsversuchen bei 560 °C für bis zu 3000 h untersucht. Die Gewichtsverluste wurden gravimetrisch bestimmt und im Ansch...

Am Beispiel der an der TU Darmstadt realisierten und vom Bundesministerium für Wirtschaft und Energie- BMWI geförderten Modellfabrik "ETA-Fabrik" kann gezeigt werden, dass mit Betonfertigteilen die Energieeffizienz von Gebäudehüllen durch eine thermische Aktivierung der raum- und der außenseitigen Bauteilschichten aus Beton eine effiziente Energiev...

Improving thermal and energy performance of historic buildings has become a relevant research theme on the pursuit of European goals for climate change and energy savings. Most of the building-stock from before 1900 is composed of natural hydraulic lime-based mortars, which has a high vapour transmission rate and, therefore, was selected as binder...

Am 20. Oktober 2017 hat das Erweiterte Präsidium die Einrichtung des Referats 10 "Präventive Konservierung" beschlossen und der Aufnahme der Tätigkeiten von vier neuen Arbeitsgruppen zugestimmt. Das Referat möchte für die am Thema interessierte Fachöffentlichkeit eine bislang fehlende Plattform bieten, um in interdisziplinärem Austausch fachliche D...

St. Georg is one of the three Romanesque churches on the island of Reichenau at Lake Constance, Germany, built between the 9th and 11th century. UNESCO inscribed the monastic island of Reichenau in the World Heritage List in 2000. St. Georg has meticulously restored wall paintings which are exposed to a very humid indoor environment. Anthro-pogenic...

In times of increasing lack of resources there is a growing demand on further development of alternative methods of power generation using renewable energy resources. Solar thermal power plants offer especially for regions with a high level of incident solar radiation a promising alternative to conventional fossil fuel power plants. To supply a rel...

In solar thermal power plants, molten salt mixtures can be used as energy storage media. When additionally applied as heat transfer media in piping systems, efficiency and economy of solar thermal power plants could be remarkably improved by avoiding the less economic heat transfer oils. The used nitrate salts are not flammable and can be disposed...

Post-installed (PI) anchors are widely used to connect structural and non-structural components (NSC) with reinforced concrete (RC) structures. For the application of PI anchors in nuclear power plants (NPP), anchors have to meet high safety requirements to assure integrity of attached components during all load cases. In the design of NPPs, the ea...

Im DBU-Vorhaben „Klimaethisches Architekturkonzept zur nachhaltigen Fortentwicklung historischer Kirchenbauwerke - Innovative Maßnahmen zur langfristigen Sicherung der Decken- und Wandmalerei am Beispiel der Katholischen Kirche St. Joseph in Osnabrück“ [1] wurde ein ganzheitliches Konzept zur Intensivierung der Nutzung einer denkmalgeschützten Groß...

Gemäß dem Prinzip form follows force fokussiert das DFG‐Schwerpunktprogramm (SPP) 1542 – Leicht Bauen mit Beton – auf die Bereitstellung beanspruchungsgerechter und ressourcenschonender Konstruktionselemente. Angesichts der in ihrer äußeren Form definierten Bauteile wie Decken, Wände und Stützen muss dieses Konzept neben der Anpassung der äußeren F...

In the upcoming years, the energy requirements for buildings will have an ascending tendency towards low energy consumption, reduction in greenhouse gases (CO2), increase of renewable energy sources and overall reduction of peak loads. Main goal of the project SWIVT (ww.swivt.tu-darmstadt.de) is to enhance and optimize energy production in an exist...

In dem Beitrag werden Ergebnisse des abgeschlossenen Forschungsvorhabens „Energetische Optimierung der Betonherstellung in Transportbetonwerken“ vorgestellt. Sechs ausgewählte Werke wurden als typische Vertreter von Transportbetonwerken nach Art und Produktionsleistung ausgewählt, um den für die Herstellung von Transportbetonen benötigten Energiebe...

Im DBU-Vorhaben "Klimaethisches Architekturkonzept zur nachhaltigen Fortentwicklung historischer Kirchenbauwerke - Innovative Maßnahmen zur langfristigen Sicherung der Decken- und Wandmalerei am Beispiel der Katholischen Kirche St. Joseph in Osnabrück" wurde ein ganzheitliches Konzept zur Intensivierung der Nutzung einer denkmalgeschützten Großkirc...

Vor 40 Jahren bildete sich der "Münchner Kreis", der im Jahr 1977 den "Wissenschaftlich-Technischen Arbeitskreis für Denkmalpflege und Bauwerksanierung e.V." gründete. Dieser wurde im Jahr 1992 in "Wissenschaftlich-Technische Arbeitsgemeinschaft für Bauwerkserhaltung und Denkmalpflege (WTA) e.V." umbenannt. Von der ersten Stunde an hat die WTA mit...

Mineralisch ummantelte Holzspäne zeigen sich gegenüber unbehandelten Holzspänen in Bezug auf das Frischbetonverhalten von gefügedichten Holzleichtbetonen und deren Eigenschaften im erhärteten Zustand im Hinblick auf Festigkeit, Dauerhaftigkeit und bauphysikalischem Verhal-ten deutlich überlegen. Bei der Verwendung der ummantelten Holzspäne als Beto...

Im Rahmen des Bewerbungsverfahrens der Materialprüfungsanstalt Universität Stuttgart (MPA Universität Stuttgart) als zugelassener AKR‐Gutachter nach ARS 04/2013 [ 1 ] wurde ein breit angelegtes Untersuchungsprogramm an der MPA in Stuttgart und am Finger‐Institut (FIB) in Weimar durchgeführt. Im ersten Teil war es zunächst anhand von Vergleichsversu...

Die „Weiße Stadt“ in Tel Aviv umfasst rund 4.000 Gebäude, davon stehen fast 2.000 unter Denkmalschutz. Damit ist die „Weiße Stadt“ das weltweit größte Architektur ensemble von Bauten der Moderne. Das Stadtquartier ist UNESCO-Weltkulturerbe, was seine architekturgeschichtliche und historische Bedeutung unterstreicht. Das Bundesbauministerium unterst...

Im Rahmen eines Verbundforschungsvorhabens wird die Gebäudehülle einer Maschinenfabrik aus vollmineralisch zementhaltigen Beton - fertig teilen erstellt. Die inneren und äußeren Bauteile werden thermisch aktiviert und sorgen für eine behagliche Raumtemperatur durch thermische Interaktion zwischen der Gebäudehülle, der Produktionshalle sowie Büros,...

Das Forschungsvorhaben analysierte verschiedene energetische Aspekte während der Betonherstellung in Transportbetonwerken. Die Forschungsgemeinschaft Transportbeton e.V. hat hierzu das Themenfeld "Vision 2015- Energetische Optimierung" initiiert, um den Energieverbrauch von Transportbetonwerken zu untersuchen.

Im Rahmen des DBU-Forschungsvorhabens wird die Wechselwirkung zwischen Raumklima und Wandmalerei unter Berücksichtigung der objektspezifischen Dynamik sich ändernder Raumklimate modellhaft untersucht. Hierbei sind die sich aus der Witterung, der Nutzung, dem Betrieb der haustechnischen Anlagen wie auch aus dem Tourismus ergebenden Beanspruchungen i...

This handbook holistically summarizes the principles of energy retrofitting historic buildings, from the first diagnosis to the adequately designed intervention: preservation of the historic structure, user comfort, and energy efficiency. The content was developed by an interdisciplinary team of researchers. The wide range of different expertise, d...

Im Projekt E-MonAut wurden Maßnahmen zur Optimierung der Betriebsführung untersucht, die mit geringem Investitionsvolumen einen großen Beitrag zur Senkung des Endenergiebedarfs erwarten lassen. Gleichzeitig wird mit dem E-MonAut Betriebsführungskonzept die Bausubstanz aktiv geschützt sowie die individuellen Nutzerbedürfnisse (Komfort- und Ökonomiek...

Eine Erhöhung der Energieeffizienz in der Industrie wird derzeit in erster Linie auf Ebene der einzelnen Maschinen durch isolierte, parallel laufende Maßnahmen erzielt. Deutlich mehr Potenzial bietet ein ganzheitlicher Ansatz, der Energieeffizienzmaßnahmen in der Produktion über die Gebäudeautomation mit der Gebäudehülle und damit der Umwelt verknü...

High-intensity mixer systems enable an increase in the amount of mixing energy. A mixer supplied by Eirich transport the material to be mixed in upward direction through an inclined rotary mixing vessel as a result of wall friction. The amount of energy introduced can be controlled and adjusted efficiently. Due to the influence of gravity and actio...

Der vorliegende Beitrag präsentiert am Institut für Massivbau der TU Darmstadt durchgeführte Forschungsarbeiten zu klima‐ und ressourcenschonenden Ökobetonen mit reduziertem Zementklinkergehalt. Es wird gezeigt, dass zur Herstellung von Betonen mit mittlerer Festigkeitsklasse (C20/25–C25/30) der Zementgehalt gegenüber konventionellen Mischungszusam...

This paper presents the results of studies at the Institut für Massivbau of the TU Darmstadt focused on the development of clinker reduced Green Concretes. The research results showed, that concrete with a cement content lower than 150 kg/m³ can be used for interior structures (C20/25, exposure class XC1). It is also possible to use concrete for ex...

Investigations were conducted at Darmstadt Technical University (TU) to demonstrate the use of regenerative raw materials in lightweight aggregate concrete. It was demonstrated that optimization needed to start with the aggregate materials, as the problems of processing and compatibility was in the nature of the organic material. The Department of...

The mix design of a durable, self-compacting concrete that is optimized using the software BétonLab Pro results in longer mixing times, which can be reduced significantly by applying multi-stage mixing processes in a high-performance cone mixer. In addition, the Theological characteristics of the concrete can be determined in the mixer for quality...

In diesem Beitrag werden zunächst die Lebensgewohnheiten der in Gebäuden vorzufindenden Schimmelpilze erörtert, um deren gesundheitsgefährdendes und auch substanzschädigendes Potenzial bewerten zu können. Anschließend sollen die üblicherweise zur Anwendung kommenden diagnostischen Methoden aufgezeigt werden. Auf dieser Basis aufbauend werden die mö...