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See detailBinary blended cement pastes and concrete using gravel wash mud (GWM) powders
Thapa, Vishojit; Waldmann, Daniele UL

in Construction and Building Materials (2021)

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See detailMachine learning in mix design of Miscanthus lightweight concrete
Pereira Dias, Patrick; Jayasinghe, Laddu Bhagya; Waldmann, Daniele UL

in Construction and Building Materials (2021)

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See detailNonlinear three-dimensional anisotropic material model for failure analysis of timber
Eslami, Hooman; Jayasinghe, Laddu Bhagya; Waldmann, Daniele UL

in Engineering Failure Analysis (2021)

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See detailInvestigation of Mycelium-Miscanthus composites as building insulation material
Pereira Dias, Patrick; Jayasinghe, Laddu Bhagya; Waldmann, Daniele UL

in Results in Materials ELSEVIER (2021)

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See detailEco-construction for sustainable development: Concept of a Material and Component Bank
JAYASINGHE, Laddu Bhagya; Waldmann, Daniele UL

in POWERSKIN Conference Proceedings (2021, April 09)

The European Commission has recently promulgated the concept of Circular Economy as a new pathway towards sustainability, in particular through new policy initiatives such as the Circular Economy Action ... [more ▼]

The European Commission has recently promulgated the concept of Circular Economy as a new pathway towards sustainability, in particular through new policy initiatives such as the Circular Economy Action Plan (CEAP). Since the environmental impact of the construction industry with the depletion of natural resources and the raising CO2 emissions will have to be reduced in the future, the need of recycling and even reusing entire building components supporting the principles of circular economy have been identified. The direct reuse of components extracted from old deconstructed buildings presents an energy-efficient and environmental-friendly solution. However, the reuse of components can be hindered by e.g. the lack of information on the availability of decommissioned structural components and uncertainties on the warranty of structural components. To handle this process an additional independent institution acting as Material and Component (M&C) Bank is needed. This entity assures activities such as e.g. the identification of reusable components in buildings which are proposed for selective dismantling; the condition assessment; the data management and the data transfer from a previously deconstructed building to a new building; and finally, an official certification of the components’ conformity for another service life in a new application. In the current paper, a concept for such a M&C bank is presented. This study investigates the potential of a M&C bank in the framework of circular economy concepts for the planning of sustainable and circular buildings with a reduced eco-footprint by focusing on the reuse of decommissioned structural components. The concept, main businesses and work operation of the bank are discussed. Furthermore, a digital representation of the bank as BIM-based M&C bank needed to publicize the availability of the reusable components to the market and to enable circular business models by showing their circular pathways are described. [less ▲]

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See detailDesign model for dry-stacked and demountable masonry blocks
Chewe Ngapeya, Gelen Gael; Waldmann, Daniele UL

in POWERSKIN Conference Proceedings (2021, April 09)

The construction industry around the world produces a large part of inert wastes mainly coming from building demolitions. Facing to this envi-ronmental challenge and considering the new policy initiatives ... [more ▼]

The construction industry around the world produces a large part of inert wastes mainly coming from building demolitions. Facing to this envi-ronmental challenge and considering the new policy initiatives supporting the designing of sustainable buildings, dry-stacked masonry comes forward as a promising solution since components can be dismantled, saved in a component bank and reassembled on new sites. The speedy growth of the construction industry, the increasing importance given to the complete life cycle of buildings and the evolution of construction technics have led to the development of dry-stacked masonry structures. Mortarless masonry structures minimise skilled labour requirements and improve construction productivity. However, despite these advantages, there are no design standards providing guidelines to assess the load-bearing capacity of dry-stacked masonry block, which therefore limits its use in construction. In an attempt to fill this lack, the current paper investigates the load-bearing capacity of dry-stacked masonry and its influencing parameters. The effects of the geometric imperfections such as height imperfections and bed-joint roughness have been analysed as well as a mitigation strategy. Then, based on experimental evidence, a design method has been proposed for dry-stacked masonry solicited by axial compression. The developed design methodology provided promising results, with 93% of accuracy in the prediction of the dry-stacked masonry’s’ load-bearing capacity. [less ▲]

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See detailModelling of mineral construction and demolition waste dynamics through a combination of geospatial and image analysis
Bogoviku, Lorenc; Waldmann, Daniele UL

in Journal of Environmental Management (2021), 282

As the construction sector is shifting towards circular economy models, the role of mineral construction materials as main waste fraction in terms of volumes is crucial. A characterization of this mineral ... [more ▼]

As the construction sector is shifting towards circular economy models, the role of mineral construction materials as main waste fraction in terms of volumes is crucial. A characterization of this mineral stock, as well as the waste derived from it is decisive in ensuring the application of the best practices of circular economy. This paper describes a methodology for assessing the mineral building stock through a combination of geospatial and image analysis. By analysing old topographic maps, buildings are grouped according to their building age into different typologies and based on these maps the construction and demolition activity is evaluated. The mineral stock is assessed and estimations of the mineral construction and demolition waste (CDW) is generated for different stochastic scenarios. This methodology is applied exemplarily on the country of Luxembourg. It was found that the total mineral construction stock for Luxembourg is 276.75 Mt and has been growing at a rate of 20.81% to 24.39% in the last 30 years. Furthermore, the study identified a mean age of the urban building stock of about 60 years and a typical maximum building lifetime of 122 years. Based on the stochastic projections the mineral CDW generated from the existing building stock is expected to be up to 226.9 Mt by 2100, while if future building scenarios are considered, it can be as high as 885.3 Mt. The annual CDW production is expected to be sufficient for a viable concrete recycling activity if regulations on the waste volume flows are made available. [less ▲]

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See detailDevelopment of New Concrete Mixes from Recycled Aggregates from known resources
Chewe, Ngapeya; Waldmann, Daniele UL

Presentation (2021, January 20)

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See detailExtended Producer Responsibility in the Construction Sector through Blockchain, BIM and Smart Contract Technologies
Akbarieh, Arghavan UL; Carbone, William; Schäfer, Markus UL et al

Poster (2020, December 09)

Despite the enormous amount of raw or secondary materials flowing within the construction industry, the actual available volume of materials and their respective End-of-Lifecycle (EoL) treatment is not ... [more ▼]

Despite the enormous amount of raw or secondary materials flowing within the construction industry, the actual available volume of materials and their respective End-of-Lifecycle (EoL) treatment is not regulated nor uniform. On top of that, the EoL responsibility of different stakeholders after the future building deconstruction is confusing and disputable. Consequently, different sustainability policies and metrics suffer from inaccurately reported volumes of circulating materials in the economy. Hence, this article aims to find a new way to improve and regulate the EoL treatment of recyclable materials and to create value for them. The ultimate goal of the proposed framework is to make original manufacturers responsible for the EoL treatment of their recyclable construction materials and products under the Extended Producers Responsibility (EPR) policy that is enacted in the European Union for sustainable management of waste streams. Adhering to the EPR is difficult for buildings as they are long-term and complex assets. A high degree of transparency, accuracy and security is required to correctly track the lifecycle information of building parts and their respective manufacturers for the EPR implementation. For this purpose, a framework is conceptualised based on the immutability and transparency of blockchain technology to remove trust and trace barriers in the current supply chain. The proposed conceptual model results from the synergy of Building Information Modelling (BIM) technology, material and component banks, blockchain technology and smart contracts for the EoL treatment of recyclable materials. As a result, a data-driven and closed-loop material cycle will be accomplished. This paper demonstrates that through self-executing smart contracts, a clear line of responsibility and ownership could be defined while manufacturers could be made accountable in the post-consumer phase of their construction products. [less ▲]

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See detailDesigning of the module envelope of a hybrid modular building to meet the passive house standards in Luxembourg
Rakotonjanahary, Tahiana Roland Michaël UL; Scholzen, Frank UL; Ferreira Silva, Marielle UL et al

in IOP Conference Series: Earth and Environmental Science (2020, November 20), 588(5), 052026

To face the challenges of climate change, new buildings need to be further greener while being able to ensure a minimum comfort to the tenants. Nonetheless, extensibility and flexibility could be added to ... [more ▼]

To face the challenges of climate change, new buildings need to be further greener while being able to ensure a minimum comfort to the tenants. Nonetheless, extensibility and flexibility could be added to buildings. In this context, the architect jointly with the team of this research project have designed a hybrid modular construction called “slab building” which is composed of a permanent concrete structure and several removable wooden modules. A module offers 27m² of living space but larger housings can be realized by combining two up to four modules. The aim of this paper is to design the walls of the modules to meet the criteria of nZEB. The thicknesses of the studied thermal insulations, namely rock wool, wood wool, polyurethane and aerogel, have been determined in accordance with the passive house requirements in Luxembourg. The embodied energy of the building materials has also been considered in the designing of the modules. Steady state calculations revealed that a wall thickness of 40 cm, comprising 31cm of insulation is sufficient but according to the LCA outcomes, there is no environmental benefit in having the modules comply with the AAA energy class requirements at reasonable wall thicknesses. [less ▲]

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See detailPerformance of lime-metakaolin pastes using gravel wash mud (GWM)
Thapa, Vishojit Bahadur UL; Waldmann, Daniele UL

in Cement and Concrete Composites (2020), 114(103772),

The performance of ternary binders using lime, metakaolin (MK) and gravel wash mud (GWM) powders is studied for the development of novel lime-pozzolan pastes. This study examines the influence of varying ... [more ▼]

The performance of ternary binders using lime, metakaolin (MK) and gravel wash mud (GWM) powders is studied for the development of novel lime-pozzolan pastes. This study examines the influence of varying mixture proportions using different types and compositions of lime powders and GWM at different treatment levels on the mechanical properties of lime-MK-GWM pastes. Various characterisation techniques including particle size distribution (PSD), X-ray fluorescence (XRF), X-ray diffraction (XRD), compressive strength tests, simultaneous thermal analysis (STA) and scanning electron microscopy (SEM), were applied on the different raw materials, respectively, on the hardened pastes to determine the reaction kinetics, the resulting microstructure and the mechanical performances of the lime-MK-GWM binder systems. Higher strength-enhancing contributions of thermally treated GWM powders (calcined at 850°C) leading to compressive strengths up to 18 MPa were confirmed and the strength-based evaluations revealed that hydrated lime-based pastes achieved higher mechanical performances than hydraulic lime-based binder systems. [less ▲]

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See detailSummertime Overheating Risk Assessment of a Flexible Plug-in Modular Unit in Luxembourg
Rakotonjanahary, Tahiana Roland Michaël UL; Scholzen, Frank UL; Waldmann, Daniele UL

in Sustainability (2020)

Modular buildings offer faster construction process, provide better construction quality, allow reducing construction waste and are potentially flexible. Frames of modular units can be made of metal ... [more ▼]

Modular buildings offer faster construction process, provide better construction quality, allow reducing construction waste and are potentially flexible. Frames of modular units can be made of metal, timber, concrete or mixed materials but lightweight structures do not always allow erecting high-rise buildings and generally present a higher risk of overheating and/or overcooling. To reconcile these pros and cons, a typology of modular building called Slab was designed by a group of architects. The building is composed on the one hand of a permanent concrete structure named shelf-structure and on the other hand of several flexible removable timber modular units, also known as modules. The shelf-structure will host the common utility rooms and will serve as docking infrastructure for the housing modules. To provide high flexibility, the Slab building was designed to adapt to any orientation and location in Luxembourg. An energy concept and a HVAC systems design has been developed for the Slab building. Furthermore, a two-fold sustainability analysis was carried out. The first part of the analysis regards the determination of the minimum required wall thicknesses of the modules in accordance with Luxembourgish regulatory requirements, although the current regulation does not yet consider the Slab building typology. The second part, which is the subject of this paper, is thermal comfort assessment, more precisely, summertime overheating risk assessment of these modules, in compliance with Luxembourgish standard. In this regard, dynamic thermal simulations have been realized on two module variants; the first fulfills the passive house requirements, and the second—the current requirements for building permit application, which in principle corresponds to low energy house requirements. Simulations showed that with adequate solar shading and reinforced natural ventilation by window opening, overheating risk could be avoided for the normal residential use scenario for both module variants. [less ▲]

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See detailEco-construction for sustainable development (Econ4SD) – Konzepte für Materialbanken
Zilian, Andreas UL; Waldmann, Daniele UL; Hertweck, Florian UL et al

in Kaliske, Michael (Ed.) 24. Dresdner Baustatik-Seminar: Reality - Modeling - Structural Design (2020, October)

This contribution presents the joint research project Econ4SD – Eco-construction for sustainable development which investigates at the University of Luxembourg various aspects of sustainable design ... [more ▼]

This contribution presents the joint research project Econ4SD – Eco-construction for sustainable development which investigates at the University of Luxembourg various aspects of sustainable design, construction and operation to support a resource-efficient circular economy in the construction sector. In this context the fundamental approach of Design for deconstruction assumes a central role and is being discussed together with the complementary concept of Material banks and their digital twinning at the level of components, buildings and markets. [less ▲]

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See detailApplication of the DAD method for damage 1 localisation on an existing bridge structure using 2 close-range UAV photogrammetry
Erdenebat, Dolgion; Waldmann, Danièle UL

in Engineering Structures (2020)

A novel damage detection and localisation method, the so-called Deformation Area Difference method for localisation of damages in bridge structures is introduced. The method is based on static load ... [more ▼]

A novel damage detection and localisation method, the so-called Deformation Area Difference method for localisation of damages in bridge structures is introduced. The method is based on static load-deflection experiments with the prerequisite of high precise deflection measurement. This study presents the first experiences of applying the DAD method on a real bridge structure. The investigated structure is a prestressed concrete slab bridge with a span of about 27 m, which was built in 2013. The loading on the bridge is applied using six heavy trucks, each weighing up to 32 t. A wide range of the modern measurement technologies were used to achieve high precision measurements of the bridge deflection along the longitudinal axis, namely the photogrammetry using a big size drone, laser scanner, total station, levelling and displacement sensors. The performed load-deflection test was non-destructive since the maximum deformation did not exceed the serviceability limit state. The exercise of the novel damage detection and localisation method on a real structure initiated further optimisation opportunities of the DAD method and the study of its limits. Several boundary conditions and methodical influence factors related to the applicability of the proposed method were analysed, such as impacts of measurement precision, damage degree, the position of damage, and the number of measurement repetitions. [less ▲]

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See detailMonotonic axial compressive behaviour and confinement mechanism of square CFRP-steel tube confined concrete
Wang, Yanlei; Cai, Gaochuang; Si Larbi, Amir et al

in Engineering Structures (2020)

Steel tube confined concrete (STCC) is widely used in the vertical members of high-rise buildings such as columns. The axial load is not directly resisted by the steel tube in STCC, but is resisted via ... [more ▼]

Steel tube confined concrete (STCC) is widely used in the vertical members of high-rise buildings such as columns. The axial load is not directly resisted by the steel tube in STCC, but is resisted via the interfacial frictional stress between steel tube and concrete core, which is different with that of concrete filled steel tube (CFT) members and would effectively suppress the outward local buckling of steel tube at early stage. Recently, fibre-reinforced polymer (FRP) confined STCC presents a potential to enhance the ductility and durability of such vertical elements. This paper presents an experimental study on monotonic axial compressive behaviour of carbon FRP (CFRP) confined STCC (CFRP- STCC) stub column and an analytical study on the confinement mechanism of and the ultimate axial bearing capacity of the elements. A three-stage confinement mechanism involving the different contributions of the steel tube and the CFRP wrap in CFRP-STCC elements was proposed based on the test results. A prediction model of the ultimate axial bearing capacity of CFRP-STCC stub columns was developed subsequently. Results show that the presence of CFRP wrap enhances effectively the load-bearing capacity and the ductility of steel tube confined plain concrete and reinforced concrete elements, and significantly prevents the local buckling of the steel tubes in the elements. The proposed prediction model of ultimate axial bearing capacity assesses test results with a great agreement. [less ▲]

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See detailDevelopment of innovative concrete mixtures aggregates
Chewe Ngapeya, Gelen Gael UL; Waldmann, Daniele UL

Scientific Conference (2020, June 22)

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See detailOptimisation of the mechanical properties of Miscanthus lightweight concrete (Top 10 Journal)
Pereira Dias, Patrick UL; Waldmann, Danièle UL

in Construction and Building Materials (2020)

In this paper, Miscanthus fibres are used to develop lightweight concrete. The amount of Miscanthus and cement, as well as the water/cement ratio, are varied to analyse the behaviour of the mixture ... [more ▼]

In this paper, Miscanthus fibres are used to develop lightweight concrete. The amount of Miscanthus and cement, as well as the water/cement ratio, are varied to analyse the behaviour of the mixture concerning the physical and mechanical properties. The Miscanthus was pre-treated with a silicate sealant or a cement-based fluid. The current paper analyses the impact of the pre-treatment of the Miscanthus fibres on the compressive strength as well as on the long-term deformations. The specimens with a pre-treatment based on a silicate sealant reached a compressive strength of 19.3 MPa, which is higher than the compressive strength of a conventional LC 16/18, a Young's Modulus above 9.9 GPa and a shrinkage deformation of 2244 μm/m. Nevertheless, considering the density the pre-treatment showed not to be beneficial. [less ▲]

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See detailImplementation of a new strain split to model unilateral contact within the phase field method
Nguyen, Thanh Tung; Yvonnet, Julien; Waldmann, Danièle UL et al

in International Journal for Numerical Methods in Engineering (2020)

A new orthogonal decomposition of strain tensor into compressive/tensile parts is implemented in the phase eld model to maintain the physical crack propagation behavior. An e cient operator split scheme ... [more ▼]

A new orthogonal decomposition of strain tensor into compressive/tensile parts is implemented in the phase eld model to maintain the physical crack propagation behavior. An e cient operator split scheme with the introduction of projection tensors is proposed to facilitate the numerical implementation of the new spectral decomposition. Formulations of the present failure model accounting the unilateral contact condition are given analytically and explicitly, which implies an extremely robust computational model. In particular, compared to the existing models, the present framework is general, which can be applied to all possible elastic behavior, such as isotropic, orthotropic, and totally anisotropic elastic material. A detailed comparison of fracture response predicted by the present models with the literature approaches is then provided. It is shown that orthogonal decomposition is able to simulate various failure scenarios. Especially, this formulation shows a very remarkably prediction compared to experimental observation for the case of compression load. [less ▲]

Detailed reference viewed: 130 (10 UL)