The construction industry faces significant challenges related to environmental sustainability, including high carbon emissions and excessive reliance on non-renewable resources. Traditional construction materials often have substantial environmental footprints. Lignin-cellulose composites, derived from renewable resources such as wood waste, can offer a promising eco-friendly alternative. However, achieving the necessary mechanical properties, printability, and scalability for practical construction applications remains a critical challenge.

This research explores the potential of lignin-cellulose biocomposites as sustainable alternatives to traditional construction materials. The study focuses on developing bio-based polymers through lignin-cellulose composites combined with bio-based binders and plasticizers, aiming to create a material suitable for hot extrusion-based additive manufacturing. By utilizing robotic additive manufacturing and parametric design approaches, the research addresses the challenges and opportunities of using bio-based materials in construction, with a primary focus on creating modular partition walls.

The primary objective of this research is to develop and optimize three distinct lignin-cellulose composite ratios, each tailored to different mechanical strength requirements. These ratios correspond to three types of bricks, strategically implemented within the partition wall according to their structural demands. Mechanical properties, rheological behavior, and printability are evaluated through a combination of experimental methods and extrusion-based fabrication processes.

Further, this study develops and tests computational slicing workflows tailored for robotic hot extrusion. Through a comparative analysis of different slicing strategies and tools, the research seeks to improve the translation of complex architectural designs into feasible robotic printing paths, optimizing material distribution according to structural performance requirements.

By integrating material innovation with computational manufacturing techniques, this research aims to demonstrate how high lignin-cellulose biocomposites can serve as a sustainable and structurally viable alternative to conventional materials. The findings will contribute insights into the advancement of bio-based composites, robotic fabrication, and computational design strategies for sustainable construction.
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The transition to a circular economy is essential in the building sector, where façades account for a significant portion of material use. Current unitized façade systems are optimized for performance but not designed for future disassembly or reuse. This research explores how façade systems can be redesigned to increase their reclamation potential, using a practical, design-based approach in collaboration with Scheldebouw, a Dutch façade manufacturer.
A literature review outlines circular design principles, with a focus on Design for Disassembly, connection techniques, and methods to evaluate disassembly potential. A case study of an existing façade element is used to identify key barriers through system analysis, factory observations, and disassembly experiments.
Multiple redesigns are developed: a modular “carrier frame” that simplifies the removal of insulating glass units (IGUs), and a screw-based thermal break connection that enables partial disassembly of aluminum profiles. These innovations aim to improve adaptability and support future reuse. The proposed designs are evaluated against existing systems in terms of thermal and disassembly potential using MOST and eDim. Results showed a significant improvement in both disassembly potential and thermal performance of the new system.
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In this master’s thesis, the pressing need for novel, bio-based and fully circular construction materials is examined. Building on existing TU Delft research, the work focuses on cellulose and lignin as the principal constituents of a new wood-like composite, using waste streams as the source. The experimental setup, inspired by a range of studies on lignin-reinforced materials, employs a hot-pressing procedure. The literature review highlights a clear gap: the combined use of cellulose and lignin, each derived from by-products, to form an innovative material matrix, with the goal to make use of lignins adhesive qualities.
The methodology includes an innovative computational method designed to provide controlled variability of structural properties, that can be directly integrated into a component design. Many material variations, like moisture content, lignin types, C/L-ratio, pre-treatment and recyclability have been explored. Principal findings from this study include identifying optimal cellulose-to-lignin (C/L) ratios for distinct mechanical performances—3:2 for flexural strength and 2:3 for compressive strength. Additionally, Soda lignin shows the best mechanical performance and the plates can be successfully reprocessed. Computational simulations using Rhino 8, Karamba3D and Wallacei proved effective in predicting and optimising mechanical properties, significantly streamlining material development. Multidimensional scaling was used to map high-dimensional material data into a two-dimensional space, clustering formulations by performance and revealing trade-offs (e.g., stiffness vs. toughness) to guide blend selection.
Microscopic analyses further supported the viability of lignin as a natural adhesive, while highlighting areas needing improvement, such as brittleness and susceptibility to warping and blistering. A link was established between mechanical testing data and component modelling, which opens up possibilities to optimise both design and material composition for sustainable and resource efficient structures.
Overall, this research successfully demonstrates the potential of fully circular waste-based cellulose-lignin composites and paves the way for scalable, high-performance, sustainable building materials. ... Read more

One of the major technological challenges in achieving circularity within the built environment is the disassembly of multi-material systems at the end of their useful life. This is especially true for façade systems, which have become more complex to improve operational performance. As efforts to reduce embodied carbon in façade systems intensify, circular economy principles, which integrate design, maintenance, and product reclamation to minimize waste and emissions, are crucial. A significant aspect of this is the emphasis on Design for Disassembly (DfD) strategies.

Yet, despite the critical importance of circular economy principles, there is a disconnect between the awareness of stakeholders in the façade industry and the evaluative methods used to assess the impact of DfD during the early design stages on the material reclamation potential at the end of a building product's lifecycle. Industry stakeholders emphasize the need for quantitative methods to determine how design choices affect reclamation potential. Thus, developing a disassembly assessment framework is essential to guide DfD efforts in façade systems and to predict outcomes at their end of life. This study seeks to address this issue by developing a framework that meets the façade industry's needs, emphasizing the evaluation of design choices on material reclamation.

By reviewing relevant literature, various factors that impact the highest reclamation potential for a façade systems were identified. These factors were organized into process maps, laying the groundwork for potential computational workflows. The factors were organized into modules that, when combined, facilitate a consistent assessment process. This research revealed that much of the necessary information is not readily processed by computational tools; it often exists in unstructured formats like text documents, and the key decision-making factors are often subjective and require human judgement. As a result, this framework proposes steps to creating databases which could improve the assessment process.

The framework's effectiveness is demonstrated through a case study of an aluminum curtain wall façade system. The assessment led to suggested design improvements that increase the potential for material recovery and reduce disassembly time at the end of life. This case study demonstrates the framework's utility and uncovers practical challenges and opportunities, serving as a model for adapting the framework to different façade typologies and building components.
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