Rebekka Volk

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• Doctor of Engineering
• Professor (Full) at University of Freiburg

Most automotive plastic waste (APW) is landfilled or used in energy recovery as it is unsuitable for high‐quality product mechanical recycling. Chemical recycling via pyrolysis offers a pathway toward closing the material loop by handling this heterogeneous waste and providing feedstock for producing virgin plastics. This study compares chemical re...

The mostly subterranean nature of district heating system pipelines makes pinpointing any occurring leakages a challenge. Airborne thermography offers a means for widespread monitoring, allowing thermal anomalies to be identified within multitudes of infrared images. This paper details a program developed to automate the entire image analysis proce...

Increasing post-demolition autoclaved aerated concrete (pd-AAC) waste is mainly landfilled due to its physical properties and lacking recycling processes. A promising technology is the production of recycled belite cement clinker, which can partially substitute Portland cement clinker. This paper presents experimental data of recycled belite cement...

Chemical recycling of complex plastic waste via pyrolysis can reduce fossil resource dependence of the plastics value chain and greenhouse gas emissions. However, economic viability is crucial for its implementation, especially considering challenging waste streams with high shares of engineering plastics that have lower pyrolysis product quality t...

Mycelium-based composites (MBCs) show promising acoustic and thermal insulation, fire safety, and mechanical strength properties and are suitable for multiple applications in the construction, packing or furniture industry. A life cycle assessment confirmed climate change and fossil energy demand benefits in a laboratory scale production modelled f...

This study quantifies external thermal insulation composite systems (ETICS), in particular expanded polystyrene (EPS) as the insulation layer, installed in Germany between 1969 and 2022. Employing a bottom‐up approach, it conducts mass quantification, localization at the NUTS‐3 level, determination of installation years, and prediction of future wa...

Deep learning (DL) is one of the key tools for analyzing images beyond the visible light spectrum, such as thermal data, for energy-related inspection and fault detection. However, publications using multispectral data focus on developing specialized models to handle quality issues without considering the imagery itself. This paper investigates how...

District heating systems offer means to transport heat to end-energy users through underground pipelines. When leakages occur, a lack of reliable monitoring makes pinpointing their locations a difficult and costly task for network operators. In recent years, aerial thermography has emerged as a means to find leakages as hot-spots, with several pape...

Concrete relies heavily on cement as a binder, is versatile and has impressive structural properties. Given the significant carbon emissions of cement, the construction industry should strive to minimise or replace its use in concrete. For this, post-demolition concrete can be used as an aggregate substitute and cement substitute. In 2021, Germany’...

The construction sector contributes 36% to global final energy use and 39% to energy-related CO2 emissions. Consequently, it is imperative to focus on quantifying and reducing environmental impacts e.g., via renewable building materials. The combination of fast-growing willow as tension reinforcement for regionally available and compression bearing...

Autoclaved aerated concrete is a popular building material in constructing one- and two-family houses because of its low thermal conductivity and fire resistance. Since autoclaved aerated concrete production rose significantly in the 1960s and 1970s, increasing post-demolition volumes can be expected in the following decades. However, these are cur...

Urban Green Space management requires a multi-dimensional, evidence-based approach to effectively balance social, environmental, and economic objectives. City administrators currently lack a data-driven framework for allocating resources during constraint scenarios, leading to subjective decisions. Existing literature lacks objective solutions for...

Autoclaved aerated concrete (AAC) is a widely used building material for masonry blocks. Its porous structure and mineral composition lead to low thermal conductivity and fire resistance. European AAC production and usage strongly increased in the 1960s and 1970s. Therefore, assuming limited buildings’ lifetimes, significant post-demolition AAC vol...

Thermal Bridges on Building Rooftops (TBBR) is a multi-channel remote sensing dataset. It was recorded during six separate UAV fly-overs of the city center of Karlsruhe, Germany, and comprises a total of 926 high-resolution images with 6927 manually-provided thermal bridge annotations. Each image provides five channels: three color, one thermograph...

This data article describes an instance dataset motivated by the problem of scheduling a project with diverging material flows. Such material flows are released during the execution of the project and are subject to limited processing and storage capacities. Typical examples are nuclear dismantling or other deconstruction/demolition projects, where...

The built environment is responsible for large shares of energy consumption as well as use of water and natural resources—contributing to resource depletion, water pollution, land use and land use change, greenhouse gas and other emissions as well as waste generation [...]

Thermal bridges are weak points of building envelopes that can lead to energy losses, collection of moisture, and formation of mould in the building fabric. To detect thermal bridges of large building stocks, drones with thermographic cameras can be used. As the manual analysis of comprehensive image datasets is very time-consuming, we investigate...

Greening cities is of considerable significance to creating sustainable cities. Cost-benefit analyses have shown that urban green is not only ecologically and socially desirable but also economically advantageous. However, maintaining this urban green is becoming challenging due to changing climatic conditions. With frequent heat-waves, droughts an...

Thermography for building audits is commonly carried out by means of terrestrial recording processes with static cameras. The implementation of drones to automatically acquire images from various perspectives can speed up and facilitate the procedure but requires higher recording distances, utilizes changing recording angles and has to contend with...

Autoclaved aerated concrete (AAC) is a popular building material for masonry units, prefabricated reinforced components, and lightweight mineral insulation boards. However, post-demolition AAC (pd-AAC) is mainly disposed in landfills. In the future, wastes are expected to increase , landfill capacities will decrease and legal framework conditions w...

Autoclaved aerated concrete (AAC) is a widely used building material for masonry units, prefabricated reinforced components, and lightweight mineral insulation boards. Its low thermal conductivity and good fire resistance increase its popularity in residential buildings. Thus, post-demolition wastes are expected to increase in the future. However,...

Urban green spaces are a critical component of cities, providing environmental, social, cultural, and economic benefits. To support smart(er) decisions by city planners and managers, this study aims to investigate how open data sources could be integrated into urban green space management. Specifically, it proposes a novel GIS-based method to prior...

Development of deconstruction and recycling standards for rotor blades (in German): As a result of the broad political support for the energy turnaround and the continued growing stock of wind turbines (WTG) in Germany and Europe, questions of maintenance, lifetime extension as well as turbine dismantling and recycling are gaining in importance....

A growing plastic production increases the pressure on waste management systems, which have to cope with greater volumes of plastic waste. Increased plastics recycling can reduce environmental impacts by lowering the need for primary plastics production and thus fossil resources demand. Current research is mainly focused on identifying environmenta...

Autoclaved aerated concrete (AAC) is used as masonry blocks and prefabricated reinforced elements preferably in residential buildings. Due to its porous structure and mineral composition, it combines low thermal conductivity and fire resistance properties. Consequently, the popularity of AAC increases. However, due to significant AAC production vol...

Thermography is commonly used for auditing buildings. Classical manual terrestrial thermography records images of individual buildings at a short distance. When auditing a large number of buildings (e.g. whole city districts) this approach reaches its limits. Using drones with thermographic cameras allows images to be recorded automatically from di...

We study the problem of scheduling construction or deconstruction projects subject to temporal and renewable resource constraints to minimize the makespan. Moreover, we take into account material flows between activities of the project. Material flows can cause delays due to the limited capacity of intermediate storage facilities. In construction p...

The current awareness of the high importance of urban green leads to a stronger need for tools to comprehensively represent urban green and its benefits. A common scientific approach is the development of urban ecosystem services (UES) based on remote sensing methods at the city or district level. Urban planning, however, requires fine-grained data...

Densely built-up areas are challenged by reduced biodiversity, high volumes of runoff water, reduced evaporation, and heat accumulation. Such phenomena are associated with imperviousness and low, unsustainable utilisation of land and exterior building surfaces. Local authorities have multiple objectives when (re-)developing future-proof districts....

Chemical Recycling of Automotive Plastics by Pyrolysis: In the past, the amount of plastic waste steadily increased in Germany. Plastic waste from automotive applications challenges existing mechanical recycling processes due to its material heterogeneity and complexity. However, chemical recycling via pyrolysis has the potential to recycle thes...

Increasing awareness of global and local climate change and the limited resources of land, surface, water, raw materials, urban green spaces, and biodiversity alter the exigencies of urban development. Already perceivable local climate changes such as heavy rains, droughts, and urban heat islands urge planners to take action. Particularly in densel...

Three-dimensional thermal mapping has been commonly used for building energy performance audits. Many researchers have focused on single building audits and modeling multiple buildings in a large district through aerial images. To solve accuracy and efficiency trade-offs, researchers have used data fusion methods to project information from thermal...

Sustainable and resilient extractive and circular economies under uncertainty" Increased uncertainty in the global economy and business environment characterised by rapid demand fluctuations and technological breakthroughs, digitization and global disruptions, creates the need for systemic transformation of extractive and construction industries. E...

This study deals with an extension of the resource-constrained project scheduling problem (RCPSP) by constraints on material flows released during the execution of project activities. These constraints arise from limited processing capacities for materials and maximum inventories of intermediate storage facilities. Production scheduling problems wi...

Global plastic production reached a new high in 2019. The high use of plastic leads to a high amount of plastic waste. Thereof, only 33% was collected for recycling in Europe. Plastic production depends on crude oil and energy and has high environmental impacts such as greenhouse gas emissions. The recycling of plastic waste can reduce dependency o...

Porenbeton ist aufgrund seiner hervorragenden Dämmeigenschaften ein häufig verwendetes Baumaterial für Mauersteine sowie vorgefertigte bewehrte Bauteile und Mineraldämmplatten – mit wachsender Beliebtheit. Altporenbeton aus dem Abbruch und Rückbau von Gebäuden wird derzeit hauptsächlich deponiert. Deponiekapazitäten nehmen jedoch ab und der rechtli...

In many industrialized countries, a significant number of buildings were constructed prior to any energy-related building construction standards. Today, single-family houses (SFH/pl. SFHs) from this time still have a comparably poor thermal quality. This paper aims to examine and model the incentive effects of the German energy retrofit funding sch...

Since the middle of the 20th century many any buildings were built without any energy standards and still have a comparably poor energy quality. To obtain an overview of the current thermal quality of buildings in a whole city district, it may be promising to work with thermographic images obtained by unmanned aerial vehicles (UAV). Aerial thermogr...

As-is building modeling plays an important role in energy audits and retrofits. However, in order to understand the source(s) of energy loss, researchers must know the semantic information of the buildings and outdoor scenes. Thermal information can potentially be used to distinguish objects that have similar surface colors but are composed of diff...

Das Projektmanagement gewinnt aufgrund kürzerer Produktlebenszyklen und eines schnelleren technologischen Wandels an Bedeutung. Für ein erfolgreiches Projektmanagement ist die Un-terstützung durch geeignete Projektmanagementsoftware erforderlich. Da hierfür zahlreiche Produkte auf dem Markt sind, befasst sich diese Studie mit einer aktuellen Bestan...

Three-dimensional thermal mapping provides many benefits for auditing building energy performance when compared with two-dimensional thermal images that provide only limited representation. However, the current thermal mapping approaches have accuracy and efficiency tradeoffs when modeling large areas using aerial images. Particularly, low-resoluti...

Worldwide, wind turbine stocks are ageing and questions of reuse and recycling particularly of rotor blades become urgent. Especially, rising rotor blade wastes face lacking good recycling options and exact quantification is difficult due to information gaps on the rotor blade size, mass and exact material composition. In a combined approach, the e...

Thermal bridges are weak areas of building envelopes that conduct more heat to the outside than surrounding envelope areas. They lead to increased energy consumption and the formation of mold. With a neural network approach, we demonstrate a method of automatically detecting thermal bridges on building rooftops from panorama drone images of whole c...

Segmenting windows and doors on 3D point cloud models allows for heat loss audits around these areas. Researchers have collected aerial images to reconstruct 3D models for large districts, but easily accessible training datasets with data acquired on ground level cannot be directly used for segmentation on 3D models reconstructed by aerial images....

The chemical industry accounts for 20% of global industrial greenhouse gas (GHG) emissions and the plastics production is increasing worldwide by approx. 4% annually. To reduce GHG emissions and increase GHG transparency in chemical value chains despite industrial secrets, we developed an approach to estimate the product carbon footprint of chemica...

Kartierung und Bewertung von Grünbeständen und deren Ökosystemleistungen in privaten Innenhöfen – Erkenntnisse einer quartiersweiten Erhebung Autoren: Denise Böhnke, Stefan Norra, Elias Naber, Rebekka Volk, Alice Krehl, Ronja Becker Eine Stadt lebt von ihrer grünen Infrastruktur, öffentlichen Parks, Gärten und kleinen Grünflächen. Nachhaltiges F...

Usage of urban data to identify de-sealing potentials in dense urban districts

Scheduling of megaprojects is very challenging because of typical characteristics, such as expected long project durations, many activities with multiple modes, scarce resources, and investment decisions. Furthermore, each megaproject has additional specific characteristics to be considered. Since the number of nuclear dismantling projects is expec...

Autoclaved aerated concrete (AAC) has a porous structure and excellent thermal properties. Therefore, it is a frequently used building material for masonry units, prefabricated reinforced components and lightweight mineral insulation boards with increasing popularity. Post-demolition AAC is currently mainly disposed of in landfills. Decreasing land...

Greenhouse gas (GHG) emissions need to be reduced to limit global warming. Plastic production requires carbon raw materials and energy that are associated today with predominantly fossil raw materials and fossil GHG emissions. Worldwide, the plastic demand is increasing annually by 4%. Recycling technologies can help save or reduce GHG emissions, b...

Three-dimensional thermal mapping from aerial images can be used in energy audits. Tie points that define the location of object points in a 3D space for reconstructing a 3D model, also include thermal information, which plays an important role in energy audits. However, it is often harder and less accurate to extract common features and determine...

Dear Colleagues, please consider submitting your contributions to the Special Issue of the Journal of Engineering Design and Technology "Sustainable and resilient extractive and circular economies under uncertainty". The submission deadline is 28 February 2021. We are looking forward to your contributions! https://www.emeraldgrouppublishing.co...

Multi-sensor imagery data has been used by researchers for the image semantic segmentation of buildings and outdoor scenes. Due to multi-sensor data hunger, researchers have implemented many simulation approaches to create synthetic datasets, and they have also synthesized thermal images because such thermal information can potentially improve segm...

The commitment of international governments to limit global warming to 2°C has led to an increased awareness and interest in sustainability from various stakeholders. Especially the ecological performances of corporations and their products regarding limiting greenhouse gas emissions (GHG) receives increasing attention. In Germany, almost 25% of th...

There is a great interest in society in making urban districts more sustainable. Sustainable and resource-efficient urban development (SDG 11) is a process that, based on the analysis of the initial situation, leads to the formulation of specific goals and must be planned, accompanied , assessed and managed. Thus, this contribution presents a funda...

In times of fast-growing stakeholder interest in sustainability, the ecological and social perspective of industrial companies and its products is gaining increasing importance. In particular, the emission of greenhouse gases (GHG) in the automotive industry has come to the forefront of public and governmental attention. The transport sector accoun...

A shortage of water leads to severe consequences for populations. Recent examples like the ongoing water shortage in Kapstadt or in Gloucestershire in 2007 highlight both the challenges authorities face to restore the water supply and the importance of installing efficient preparedness measures and plans. This study develops a proactive planning ap...

Greenhouse gas (GHG) emissions need to be reduced to limit global warming. Plastic production requires carbon raw materials and energy that are associated today with predominantly fossil raw materials and fossil GHG emissions. Worldwide, the plastic demand is increasing annually by 4%. Recycling technologies can help saving or reducing GHG emission...

To manage (natural) resources efficiently, their use has to be measured and assessed. Therefore, a management support tool for city planners and other stakeholders on district level is developed based on requirements (A). The basis is an adaptable set of core and optional indicators that are structured into "fields of interest" (B). This is complem...

Der vorliegende Schlussbericht des Forschungsprojektes „StAR-Bau“ wurde im Rahmen des Programms Nachhaltiges Bauen (NaBau) der Baden-Württemberg Stiftung erstellt. Das Projekt untersucht aktuelle und zukünftige Stoffströme im Bauwesen von Baden-Württemberg. Dafür wurde ein geeignetes regionales Stoffstrommodell für Gebäude und Straßeninfrastruktur...

Energy use related to buildings accounts for 35.3% of Germany's final energy consumption and nearly a third of greenhouse gas emissions. Thus, deep energy retrofit (DER) has a substantial role in the German energy efficiency strategy. Although many DER measures are economically viable, the pace of DER is below expectations and target value. A few s...

A sustainable economy fulfills societal needs in a fundamentally different way to the current economic system. Improvements to the efficiency of existing technologies or practices appear insufficient for achieving sustainable development within the planetary boundaries. Disruptive, systemic and transformational changes appear necessary in order to...

Infrared Thermography (IRT) is a widely used non-destructive method for energy audits. However, plenty of research indicates that the performance of passive thermography is influenced by the method of data collection. Unmanned Aircraft Systems (UAS) has been successfully employed for conducting RGB photogrammetry, but the data collected from an inf...

Material flows in the construction and demolition (C&D) sector remain high in many countries. But, their changes or reductions are essential for successful circular economies. Existing material flow analyses do not cover regional characteristics, stakeholders and impacts of policy measures and interactions. We contribute a new, unprecedented way o...

In the 1950s, nuclear power generation became important and many facilities were built. Today, because of political, technical or economic reasons many reactors are being or will be decommissioned. This highly impacts energy policy regarding future energy supply and the handling of decommissioning, including dismantling capacities, regulatory contr...

In the 1950s, nuclear power generation became important and many facilities were built. Today, because of political, technical or economic reasons many reactors are being or will be decommissioned. This highly impacts energy policy regarding future energy supply and the handling of decommissioning, including dismantling capacities, regulatory contr...

During their lifecycles, buildings are changed and adapted to the requirements of generations of users, residents and proprietaries over several decades. At the end of their life time, buildings undergo either retrofit or deconstruction (and replacement) processes. And, modifications and deviations of the original building structure, equipment and...

In Folge intensiver Forschungs- und Entwicklungsarbeiten konnten bisher eine Vielzahl von Techniken und Verfahren zum Rückbau kerntechnischer Anlagen neu- bzw. weiterentwickelt und in der Praxis getestet werden. Verschiedene in der Vergangenheit erfolgreich durchgeführte Rückbauprojekte sowie der Fortschritt bei laufenden Rückbauprojekten belegen,...

By assessing the emissions of greenhouse gases of finished goods over their entire lifecycle, it can be seen that a significant part of the emissions is caused in production and related upstream processes. A strong focus on resource-efficient production techniques could provide possibilities for significant emission reduction in these processes. Th...

Several project management standards (PM standards) support project management (PM) to accomplish project objectives. The selection of an appropriate PM standard is a strategic decision that should have been done very carefully because of its great impact on project success. Since there is a lack of studies which analyse and compare PM standards to...

Several project management standards (PM standards) support project management (PM) to achieve project objectives. The selection of an appropriate PM standard is a strategic decision that should be made very carefully because of its great impact on project success. The aim of this study is to analyse and compare different PM standards and to recomm...

Die Reaktorkatastrophe im japanischen Fukushima im Jahr 2011 führte in vielen Ländern weltweit zu einer Neubewertung der Risiken, die mit der Nutzung der Kernenergie verbunden sind. In der Folge wurde beispielsweise in Deutschland die vorzeitige Außerbetriebnahme von acht Leistungsreaktoren beschlossen und ein Ausstieg aus der Kernenergienutzung zu...

In recent decades, the shortage of natural resources like primary raw materials has increasingly shifted into the focus of public discussion and research. Especially in the resource-intensive construction sector the implementation of a circular economy can strongly contribute to a reduction of primary resource demand. Positive developments can be n...

Purpose The purpose of this paper is to provide a comprehensive overview of literature and methods that can be used for deconstruction project planning of buildings. Furthermore, shortcomings of the identified planning methods are presented and research gaps are identified. Design/methodology/approach Requirements to consider for the planning of d...

A considerable share of greenhouse gas (GHG) emissions is caused by the energy consumption for space heating and cooling in residential buildings. In Germany for instance about one third of the end energy consumption is accounted to space heating and cooling of buildings. Consequently, efforts to increase energy efficiency and substitute non-renewa...

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In this research, a project planning and decision support model is developed and applied for deconstruction projects to identify and reduce risk and uncertainty in deconstruction project planning. To support decision makers in deconstruction project planning, a proactive scenario construction is developed that considers three main uncertainties in...

Nowadays, due to globally increasing building densities in cities, demolition works are an inherent part of construction. And they are focal activities related to life-cycle-oriented management of construction materials, which aims at drastically reduce the deployment and consumption of primary non-renewable construction materials. To give an overv...

As energetic, health and environmental requirements for buildings are changing, deconstruction of buildings in the course of retrofits or replacing construction is increasingly important. To plan change measures in existing buildings, buildings have to be audited manually which is associated with great effort. In our contribution, we propose and de...

Buildings are characterized by their immobility, heterogeneity and uniqueness. Due to their long lifecycles, buildings undergo several decades and are refurbished, retrofitted, remediated or modernized by generations of users, residents and proprietaries. Some buildings cannot economically be adapted to meet these requirements. The buildings in que...