Hanaa Dahy

Abstract

The building industry is increasingly adopting bio-based materials to meet the growing demand for environmentally friendly alternatives. Composites, known for their diverse properties and adaptable geometries, are gaining popularity as a versatile choice for customising materials for specific applications. This paper presents a 3D scanning methodology to enhance construction accuracy with sustainable building materials. It introduces three fabrication technologies for fibre-reinforced biocomposites and the resulting building components and structures at different scales achieved with each method. Pultrusion is employed to produce natural fibre biocomposite profiles used in an active-bending structural system. 3D Printing (3DP) is utilised to create a modular column using natural fibre-reinforced bioplastic, while Tailored Fibre Placement (TFP) is applied to fabricate biocomposite facade panels with varying geometries. The three case studies demonstrate the use of scanning technology to improve fabrication and assembly processes, with geometric accuracy evaluated through Terrestrial Laser Scanning (TLS) during construction, allowing for a detailed comparison of the built structures with the digital models. Scanning revealed that pultrusion produced accurate components but exhibited up to 160 mm deviations in large-scale freeform assemblies. 3DP can achieve high component manufacturing accuracy with deviations below 5 mm, though modular assembly introduced accumulated errors reaching 40 mm. TFP deviations varied between −48 and 60 mm, with different shaping approaches helping to reduce errors. A comparative analysis of the three methods provides recommendations for improving fabrication and assembly processes while establishing a framework for the future integration of biocomposites as structural components in architectural systems.

Abstract

Material selection is essential for advancing sustainability in construction. Biocomposites contribute significantly to raising the awareness of materials derived from biomass. This paper explores the design development and application of novel natural fibre pultruded biocomposite profiles in a deployable system. Development methods include geometrical studies to create a system that transforms from flat to three-dimensional. Physical and digital models were used to refine the geometry, while connection elements were designed to suit material properties and deployability requirements. The first case study, at a furniture scale, demonstrates the use of the profiles connected using threading methods to create a lightweight multifunctional deployable system enabling easy transport and storage. This system can be locked at various heights for different purposes. The realised structure weighs 4 kg, supporting weights up to 150 kg. The second case study applies the system architecturally in an adaptive kinetic facade, adjusting to the sun’s position for optimal shading, providing up to 70% daylight when open and as little as 20% when closed. These two structures validate the developed deployable system, showcasing the versatility of biocomposite profiles in such configurations. This approach enhances sustainability in architecture by enabling lightweight, adaptable, and eco-friendly building solutions.

Abstract

The growing demand for eco-friendly alternatives within the construction industry has promoted the use of bio-based materials. This research highlights the innovative application of newly developed natural fibre biocomposite profiles in structural systems through the creation of the LightPRO Shell. These biocomposite profiles are manufactured using the pultrusion technique, commonly used for fabricating composites with synthetic fibres, however, these profiles were crafted from natural flax fibres. This research details the processes involved in realising a full-scale structural demonstrator employing the developed profiles. The chosen application spotlights an active-bending structure, emphasising the profiles' remarkable flexibility. This article focuses on the methods and techniques employed in the realisation of this structure, from the joint typologies and prefabrication of components to the final assembly of the entire system. Essential aspects of the construction phase and erection process of this lightweight structure are discussed. Additionally, it explores concepts related to assembly and disassembly strategies, providing a comprehensive overview of the construction phases. The realised structure serves as a proof of concept, showcasing the viability of integrating natural fibre biocomposites into structural systems while offering sustainable alternatives for the architecture and construction industry.

Abstract

The utilisation of bio-based materials has significantly increased in recent years, driven by a growing awareness of environmentally friendly alternatives in the construction industry. This study introduces innovative natural fibre pultruded profiles for load-bearing applications in structural systems. By employing pultrusion technology with flax fibres and customised plant-based matrix, linear and unidirectional biocomposite profiles were developed. These profiles were used in the creation of LightPRO Shell, an active-bending structure combining biocomposite profiles with a membrane outer skin, demonstrating their mechanical properties and suitability for such applications. The paper focuses on the geometrical and structural design development of the structure employing computational design tools for optimisation, ensuring design parameters and performance requirements were met. The final structure, a 10-m span doubly curved gridshell, features a continuous perimeter beam and consists of 44 profiles ranging from 6 to 12.5 m, showcasing the potential of natural fibre biocomposites as sustainable alternatives in construction.

Abstract

Reevaluating the materials that shape our built environment holds significant importance for sustainable construction. This research introduces newly developed natural fibre pultruded profiles, composed of flax fibres and bio-resin, customised for specific properties and targeted applications. Engineered to withstand both bending and compression loads, these profiles have been subjected to rigorous mechanical testing to demonstrate their compression and flexural strength, as well as flexibility. The emphasis lies on the bottom-up design approach, guiding the creation of applications suitable for this innovative material in various lightweight structures. The paper presents a series of case studies showcasing the use of biocomposite profiles in diverse design and structural contexts. The initial focus was on active-bending structures, highlighting the material’s flexibility, showcased at a ten-metre span structure, the first large-scale demonstrator. However, given the material’s versatile properties, it is suitable for a wide range of other applications. Key case studies discussed include reciprocal, tensegrity and deployable structures, as well as modular planar or space frame systems. These profiles offer a sustainable and versatile alternative to traditional materials and composites, providing innovative and eco-friendly construction solutions while contributing to industry sustainability goals.

Abstract

Material selection is crucial for advancing sustainability in the building sector. While composites have become popular, biocomposites play a pivotal role in raising awareness of materials deriving from biomass resources. This study presents a new linear biocomposite profile, fabricated using pultrusion technology, a continuous process for producing endless fiber-reinforced composites with consistent cross-sections. The developed profiles are made from flax fibers and a plant-based resin. This paper focuses on the application of these profiles in tensegrity systems, which combine compression and tension elements to achieve equilibrium. In this study, the biocomposite profiles were used as compression elements, leveraging their properties. The methods include geometrical development using physical and digital models to optimize the geometry based on material properties and dimensions. A parametric algorithm including physics simulations was developed for this purpose. Further investigations explore material options for tension members and connections, as well as assembly processes. The results include several prototypes on different scales. Initially, the basic tensegrity principle was built and explored. The lessons learned were applied in a final prototype of 1.5 m on a furniture scale, specifically a chair, integrating a hanging membrane serving as a seat. This structure validates the developed system, proving the feasibility of employing biocomposite profiles in tensegrity configurations. Furthermore, considerations for scaling up the systems to an architectural level are discussed, highlighting the potential to enhance sustainability through the use of renewable and eco-friendly building materials, while promoting tensegrity design applications.

Abstract

The use of bio-based materials has been increasing in recent years owing to a growing awareness of ecologically friendly alternatives in the building industry. This work demonstrates the application of natural fiber biocomposite profiles within a reciprocal structural framework. Employing the pultrusion technique, linear profiles are fabricated using natural flax fibers and a bio-based resin. This paper focuses on the design and implementation of a parametric model that generates reciprocal systems considering the geometric and mechanical properties of this newly developed material. Reciprocal systems were chosen due to their high density of shorter linear elements, capacity for global geometric diversity, simplicity of joint assemblies, and low structural dependence on the joints. The developed algorithm considers material properties and site requirements to transform a line network into a stable reciprocal system with given cross-sections and generates pre-fabrication and assembly instructions to reduce on�site complexity. The proposed method was initially validated with a small demonstrator, confirming its accuracy from design to fabrication. A larger canopy showcased at the Venice Biennial demonstrated the system's scalability and the applicability of biocomposite profiles for complex applications.

Abstract

Reconsidering the materials used in construction is crucial within the building industry, particularly in the context of sustainability. Recently, there has been a growing interest in exploring novel materials, with fibre-reinforced composites emerging as a prominent choice with biocomposites standing out as promising for advancing sustainability goals. This paper introduces the development of LeichtPRO-Profiles, continuous linear biocomposite profiles fabricated using the pultrusion technology. A primary focus is the application of these profiles in structural systems as load-bearing elements, emphasising the significance of understanding their mechanical properties. Specifically, an original application involves active-bending structures, necessitating a focus on the material’s bending behaviour. This study discusses the methods employed in developing the pultruded biocomposite profiles which are made from natural flax fibres and an optimised matrix formulation based on a plant-based resin system. This research also outlines the optimisation of the fabrication process of these biocomposite profiles using bio-based ingredients. The results demonstrate the material’s mechanical capabilities through extensive experiments and mechanical tests, revealing a compression strength of 31.2 kN and a flexural strength of 300 MPa, with a bending radius of up to 2.4 m, indicating its suitability for structural applications. Concepts of applications in several systems across different scales and contexts are also presented. The versatility and adaptability of this product make it suitable for a wide range of applications spanning various scales and thematic contexts.

Abstract

The selection of materials in the construction industry plays a pivotal role in advancing sustainability goals. Traditional materials derived from natural resources face inherent constraints linked to geographic limitation, growth time, and geometric inconsistency and therefore recent attention has shifted towards developing novel bio-based materials. Composites, offering varying properties and geometries, are becoming increasingly popular for customising materials for specific applications. Pultrusion, a technology for manufacturing linear fibre-reinforced composites, is a well-established and reliable method. This study delves into optimising pultrusion technology, which traditionally relies on synthetic fibres, by exploring the potential of natural alternatives, specifically hemp bast fibres. Additionally, it presents a customised formulation based on a plant-based resin and additives. This formulation is tailored for pultrusion to produce high-performance biocomposites for use as load-bearing components in structural applications, with an initial focus on bending structures. The study elaborates on the material composition and performance of these newly developed natural fibre pultruded profiles, showcasing their mechanical capabilities through rigorous experimentation and testing. The results demonstrate the material's mechanical capabilities showcasing a flexural strength of 260 MPa with a bending modulus of 21 GPa and a bending radius reaching 0.5 m. While this study focuses on the material formulation tested on laboratory-scale pultrusion, the findings will be later applied in an upscaled production at an industrial level, aiming to enhance overall sustainability in the construction industry.

Abstract

In recent years, there has been a resurgence of interest in construction with raw earth due to its sustainability and reusability. Despite increased and diverse academic research on digital tools like 3D printing, standard earthen construction techniques and typologies have seen limited evolution. Consequently, the building industry continues to rely on the standardised concrete. This paper proposes novel modelling methods for clay-fiber-fabric hybrid structures, with stay-in-place formworks. Integrating computational processes to the material system expands the design space for performative, lightweight earthen components. Reinforcement patterns for flax fibers are generated from combining the properties of woven jute fabric, material experiments, informed structural behaviours and fabrication requirements. The proposed design-to-fabrication workflow can leverage the benefits of earth-fabric hybrids, enabling structures not solely reliant on compressive forces, unlike traditional earth buildings. This new design space is explored through branching typologies, ideal for large spans and bending moments. Using 3DGS form-finding and polygonal modelling, complex shapes can be created with high accuracy. Material behaviour simulations inform design and structural analysis, ensuring reductions in deviation from the desired form. This research combines these methods in a comprehensive computational framework for modelling clay-fabric-fiber hybrid structures, with enhanced structural performance, fabrication accuracy and potential for off-site prefabrication, leading to more control, accessibility, and appeal for future architects.

Abstract

In a resource-constrained world, raising awareness about the development of eco-friendly alternative materials is critical for ensuring a more sustainable future. Mycelium-based composites (MBC) and their diverse applications are gaining popularity as regenerative, biodegradable, and lightweight alternatives. This research aims to broaden the design potentials of MBC in order to construct advanced systems towards a novel material culture in architecture. The proposed design method intends to explore the design and fabrication of small-scale components of MBC to be applied in modular systems. Mycelium-based modular components are being developed to fulfill the geometrical requirements that allow for the creation of a lightweight system without additional reinforcement. The modules are linked together using an interlocking system. Through computational design and form-finding methods, various arrangements of the modules are achieved. An initial prototype of five modules is created to demonstrate the ability of the system to form various geometrical configurations as a result of the used workflow. The proposed application aims to expand the scope of the use of mycelium-based composites in modular systems and to promote architectural applications using bio-based composite materials.

Abstract

The building industry needs to innovate towards a more sustainable future and can do so through a combination of more renewable material choices and less wasteful fabrication processes. To address these issues, a hybrid material and fabrication system was developed using laminated timber veneer and natural fibre-reinforced composites (NFRPs), two materials that are leveraged for their potential of strategic material placement in additive processes towards programmed material behaviour and performance. The main contribution is in the hybrid fabrication approach, using thin, bent laminated veneer as an embedded frame for coreless filament winding of NFRP, which removes the need for temporary, wasteful formwork that is typically required to achieve structurally performative bent timber or FRP elements. Integrative methods are developed for the design, simulation, and fabrication of a rocking chair prototype that illustrates the architectural potential of the developed fabrication approach.

Abstract

The paper discusses how adaptation of Automated Preforming (AP) technology for fabrication of customized profiles from flax textiles laminated with biobased resins may offer new structural design possibilities and prospects for increasing the use of biocomposites in architecture. As the fabrication process may offer specific customization options, their potential impact on the design possibilities are considered. The concept is validated through realization of a 1:1 structural demonstrator. Specific limitations imposed by the technology are reflected in the design decisions. The successful realization of the structure is the base for speculation about further steps regarding automation attempt and upscaling of the design.

Abstract

There is an essential need for a change in the way we build our physical environment. To prevent our ecosystems from collapsing, raising awareness of already available bio-based materials is vital. Mycelium, a living fungal organism, has the potential to replace conventional materials, having the ability to act as a binding agent of various natural fibers, such as hemp, flax, or other agricultural waste products. This study aims to showcase mycelium’s load-bearing capacities when reinforced with bio-based materials and specifically natural fibers, in an alternative merging design approach. Counteracting the usual fabrication techniques, the proposed design method aims to guide mycelium’s growth on a natural rattan framework that serves as a supportive structure for the mycelium substrate and its fiber reinforcement. The rattan skeleton is integrated into the finished composite product, where both components merge, forming a fully biodegradable unit. Using digital form-finding tools, the geometry of a compressive structure is computed. The occurring multi-layer biobased component can support a load beyond 20 times its own weight. An initial physical prototype in furniture scale is realized. Further applications in architectural scale are studied and proposed.

Abstract

Under normal conditions, the cross-sections of reinforced concrete in classic skeleton construction systems are often only partially loaded. This contributes to non-sustainable construction solutions due to an excess of material use. Novel cross-disciplinary workflows linking architects, engineers, material scientists and manufacturers could offer alternative means for more sustainable architectural applications with extra lightweight solutions. Through material-specific use of plant-based Natural Fiber-Reinforced Polymer Composites (NFRP), also named Biocomposites, a high-performance lightweight structure with topology optimized cross-sections has been here developed. The closed life cycle of NFRPs promotes sustainability in construction through energy recovery of the quickly generative biomass-based materials. The cooperative design resulted in a development that were verified through a 1:10 demonstrator, whose fibrous morphology was defined by biomimetically-inspired orthotropic tectonics, generated with by the fiber path optimization software tools, namely EdoStructure and EdoPath in combination with the appliance of the digital additive manufacturing technique: Tailored Fiber Placement (TFP).

Abstract

The application of non-renewable building materials including concrete and metals in construction industries have caused a major impact on the environment including the destruction of more than 45% of the global resources, the consumption of 35% of energy and nearly 40% of energy-related emissions (UN Secretary-General’s High-Level Panel on Global 2012). In order to help in reducing these extending impacts, the building sector started considering three reduction of these dreadful impacts through increasing the environmentally-friendly building materials with Natural Fiber Reinforced Polymer Composites (NFRP), specially through WPCs (Wood Polymer Composites) since the 90s. The use of natural fibers in composites form in the building sector is historically applied since the phrase time when straw and mud were mixed to form the first known bricks in history. After the discovery of cement, it became the largest dominant material in the industry till our current time, in spite of its huge environmental damage. Natural fibres (NF) have been mostly applied in non-structural applications. Accordingly, this paper discusses applying reinforcement scenarios in the form of novel core and veneer reinforcement to enhance a load-bearing capacity to reach to improved mechanical properties that could enable building a demo- shell construction system. In this research natural fiber reinforced polymer composite (NFRP) produced from agricultural residues in the form of straw fibres (SF) mixed with three different types of polymers including (polylactide (PLA), a TPE (Thermoplastic elastic polymer) and high-density polyethylene (HDPE)) were developed through extrusion processes, then laminated or veneered to elevate the material properties needed to be reached to apply in load-bearing structures. The thermoplastic elastic polymers (TPE) were applied to enhance elasticity and flexibility in reaching sophisticated geometries. The mechanical strength was controlled by veneering. The targeted and reached material properties were applied in structural simulations that were later used in predicting the structural performance of a physical experimental shell construction that were built to validate the settled hypothesis of reinforcement of elastic/semi-elastic lignocellulosic cores to be applied in load-bearing systems. The paper will highlight the material samples development and testing, followed by an analysis and interpretation to the possibility of usage and appliance in load-bearing structures. Finally, the physical built demonstrator in the form of the experimental shell construction is shortly illustrated to showcase the validity of the settled hypothesis.

Abstract

This research demonstrates an integrative computational design and fabrication workflow for the production of surface-active fibre composites, which uses natural fibres, revitalises a traditional craft, and avoids the use of costly molds. Fibre-reinforced polymers (FRPs) are highly tunable building materials, which gain efficiency from fabrication techniques enabling controlled fibre direction and placement in tune with load-bearing requirements. These techniques have evolved closely with industrial textile processes. However, increased focus on automation within FRP fabrication processes have overlooked potential key benefits presented by some lesser-known traditional techniques of fibre arrangement. This research explores the process of traditional bobbin lace-making and applies it in a computer-aided design and fabrication process of a small-scale structural demonstrator in the form of a chair. The research exposes qualities that can expand the design space of FRPs, as well as speculates about the potential automation of the process. In addition, Natural Fibre-Reinforced Polymers (NFRP) are investigated as a sustainable and human-friendly alternative to more popular carbon and glass FRPs.

Abstract

Fiber Reinforced Polymers (FRPs) are increasingly popular building materials, mainly because of their high strength to weight ratio. Despite these beneficial properties, these composites are often fabricated in standardized mass production. This research aims to eliminate costly molds in order to simplify the fabrication and allow for a higher degree of customization. Complex three-dimensional shapes were instead achieved by a flat reinforcement, which was resin infused and curved folded into a spatial object before hardening. Structural stability was gained through geometries with closed cross-sections. To enable this, the resource-saving additive fabrication technique of tailored fiber placement (TFP) was chosen. This method allowed for precise fibers’ deposition, making a programmed anisotropic behavior of the material possible. Principles regarding the fiber placement were transferred from a biological role-model. Five functional stools were produced as demonstrators to prove the functionality and advantages of the explained system. Partially bio-based materials were applied to fabricate the stool models of natural fiber-reinforced polymer composites (NFRP). A parametric design tool for the global design and fiber layout generation was developed. As a result, varieties of customized components can be produced without increasing the design and manufacturing effort

Abstract

It has become clear over the last decade that the building industry must rapidly change to meet globally pressing requirements. The strong links between climate change and the environmental impact of architecture mean an urgent necessity for alternative design solutions. In order to propose them in this project, two emergent fabrication techniques were deployed with natural fiber-reinforced polymers (NFRPs), namely tailored fiber placement (TFP) and coreless filament winding (CFW). The approach is explored through the design and prototyping of a stool, as an analogue of the functional and structural performance requirements of an architectural system. TFP and CFW technologies are leveraged for their abilities of strategic material placement to create high-performance differentiated structure and geometry. Flax fibers, in this case, provide a renewable alternative for high-performance yarns, such as carbon, glass, or basalt. The novel contribution of this project is exploring the use of a TFP preform as an embedded fabrication frame for CFW. This eliminates the complex, expensive, and rigid molds that are traditionally associated with composites. Through a bottom-up iterative method, material and structure are explored in an integrative design process. This culminates in a lightweight FlexFlax Stool design (ca. 1 kg), which can carry approximately 80 times its weight, articulated in a new material-based design tectonic.

Abstract

Driven by the ecological crisis looming over the 21st century, the construction sector must urgently seek alternative design solutions to current building practices. In the wake of emergent digital technologies and novel material strategies, this research proposes a lightweight architectural solution using natural fiberreinforced polymers NFRP, which elicit interest for their inherent renewability as compared to highperformance yarns. Two associated fabrication techniques are deployed tailored fiber placement TFP and coreless filament winding CFW, both favored for their additive efficiencies granted by strategic material placement. A hypothesis is formed, postulating that their combination can leverage the standalone complexities of molds and frames by integrating them as active structural elements. Consequently, the TFP enables the creation of a 2D stiffnesscontrolled preform to be bent into a permanent scaffold for winding rigid 3D fiber bodies via CFW. A proof of concept is generated via the smallscale prototyping and testing of a stool, with results yielding a design of 1 kg capable of carrying 100 times its weight. Laying the groundwork for a scaledup architectural proposal, the prototype instigates alterations to the process, most notably the favoring of a modular global design and lapped preform technique. The research concludes with a discussion on the resulting technoimplications for automation, deployment, material life cycle, and aesthetics, rekindling optimism towards future sustainable practices.

Abstract

Carbon fiber composites embody lightweight and strength and is a well-integrated material in various fields of engineering. In spite of its excellent material properties, it is not frequently found in architecture and design applications. In this project, the intention is to research how the material's most prominent qualities can be applied to create a lightweight furniture design. The furniture object was chosen as an example of a small architectural component with a structural capacity of holding a human body weight between 60-90 Kg. In particular, carbon fiber composites display an impressive tensile strength, and with the aim of exploring this feature, a case-study of a full-scale, hanging carbon chair was conducted. To develop a design, optimize it and realize it, an integrated design and fabrication process was developed. It combined material research, computational design, and a novel fabrication method for filament materials.

Abstract

Choosing building materials is usually the stage that follows design in the architectural design process, and is rarely used as a main input and driver for the design of the whole building’s geometries or structures. As an approach to have control over the environmental impact of the applied building materials and their after-use scenarios, an approach has been initiated by the author through a series of research studies, architectural built prototypes, and green material developments. This paper illustrates how sustainable building materials can be a main input in the design process, and how digital fabrication technologies can enable variable controlling strategies over the green materials’ properties, enabling adjustable innovative building spaces with new architectural typologies, aesthetic values, and controlled martial life cycles. Through this, a new type of design philosophy by means of applying sustainable building materials with closed life cycles is created. In this paper, three case studies of research pavilions are illustrated. The pavilions were prefabricated and constructed from newly developed sustainable building materials. The applied materials varied between structural and non-structural building materials, where each had a controlled end-of-life scenario. The application of the bio-based building materials was set as an initial design phase, and the architects here participated within two disciplines: once as designers, and additionally as green building material developers. In all three case studies, Design for Deconstruction (DfD) strategies were applied in different manners, encouraging architects to further follow such suggested approaches.

Abstract

Due to the high amounts of waste generated from the building industry field, it has become essential to search for renewable building materials to be applied in wider and more innovative methods in architecture. One of the materials with the highest potential in this area is natural fibre-reinforced polymers (NFRP), which are also called biocomposites, and are filled or reinforced with annually renewable lignocellulosic fibres. This would permit variable closed material cycles’ scenarios and should decrease the amounts of waste generated in the building industry. Throughout this paper, this discussion will be illustrated through a number of developments and 1:1 mockups fabricated from newly developed lignocellulosic-based biocomposites from both bio-based and non-bio-based thermoplastic and thermoset polymers. Recyclability, closed materials cycles, and design variations with diverse digital fabrication technologies will be discussed in each case. The mock-ups’ concepts, materials’ compositions, and fabrication methods are illustrated. In the first case study, a structural segmented shell construction is developed and constructed. In the second case study, acoustic panels were developed. The final case studies are two types of furniture, where each is developed from a different lignocellulosic-based biocomposite. All of the presented case studies show diverse architectural design possibilities, structural abilities, and physical building characteristics.

Abstract

Technological advancement culminating in a globalized economy has brought tremendous improvements for mankind in manifold respects but comes at the cost of alienation from nature. Human activities nowadays are unsustainable and cause severe damage especially in terms of global depletion and destabilization of natural systems but also harm its own social resources. In this paper, a sustainability assessment method is developed based on a bio-inspired sustainability framework that has been developed in the project TRR 141-C01 “The biomimetic promise”. It is aims at regaining the advantages of societal embeddedness in its environment through biological inspiration. The method is developed using a structured approach including requirement specification, description of the inventory models on bio-inspiration and sustainability assessment, creation of a bio-inspired sustainability assessment model and its validation. It is defined as an accompanying assessment for decision support, using a six-fold two-dimensional structure of social, economic and environmental functions and burdens. The method is applied and validated in 6 projects of TRR 141 and its applicability is exemplarily shown by the assessment of “Bio-flexi”, a biobased and biodegradable natural fiber reinforced plastic composite for indoor cladding applications. Based on the findings of the application the assessment method itself is proposed to be advanced towards an adaptive structure and a consequent outlook is provided.

Abstract

Natural fibres retrieved from annual agricultural by-products offer diverse advantages, when applied as a main ingredient in biocomposite building materials. These fibres, such as straw and other non-wood fibres are annually renewable and are worldwide available having the lowest cost, in comparison to other natural fibres available in the industrial fibre market. In this paper, the author presents three case studies of natural fibre reinforced polymers (NFRP), discussing the agro-fibre densification, different architectural designs for customized applications and fabrication stages. The natural fibres were compounded with three different biopolymers: a thermoplastic, a thermoset and an elastic thermoplastic one. This allowed variations in the final designs and geometries that can be reached, but caused a necessity of changing the fabrication technique in each case accordingly. To prove the applicability of the developed products, mechanical properties and environmental assessment were analyzed.

Abstract

Cellulosic fibres retrieved from annual agricultural by-products offer diverse advantages when applied as a main ingredient in biocomposite building materials. Within this paper work, the application possibility of non-wood straw fibres in innovative building products is highlighted. Fabrication efficiency is reached here through reducing the number of industrial processes and additives needed to manufacture the final biocomposite products. The natural mineral contents of the straw selected (rice straw) were investigated at 20% fibre load as active flame-retardant fillers in combination with two types of bio-based synthesized thermoplastics poly-lactic acid (PLA) and Lignin. Flammability behavior and morphological examinations of the resulted building materials were tested. Through post-fabrication techniques including vacuum thermoforming processes, a variety of cladding panels with different architectural designs were achieved. The applied fibres were not chemically treated. Instead, the fibres were mechanically densified, maintaining the inner natural minerals contents. The results have shown promising possibility of applying straw fibres as partial replacement of classic flame-retardants especially in combination with bioplastics. The straw based green biocomposites were proved to offer high ecological, economical and aesthetic input in the building industry.

Abstract

Aus dem Bewusstsein für globale Umweltbedingungen, Nachhaltigkeitsprinzipien, ökologische Effizienz und architektonische Bedürfnisse heraus wurde in diesem Forschungsvorhaben das Potenzial von Reisstroh in der Bauindustrie sorgfältig untersucht. Reisstroh (RS) wurde als Beispiel für faserigen Pflanzenabfall gewählt, da diese Naturfasern weltweit zur Verfügung stehen, aber immer noch in großen Mengen auf den Feldern verbrannt werden. Die Zerstörung des nutzbaren Pflanzenmaterials führt zu Verlust von Energie, gleichzeitiger Luftverschmutzung und negativer Klimaveränderung. Bisher finden bereits Strohballen in der Bauindustrie Verwendung. Diese können jedoch die verfügbaren Strohmengen nicht aufnehmen und haben technische und ästhetische Nachteile. Demzufolge wurde hier vorgeschlagen, Stroh als Hauptbestandteil eines Bioverbundwerkstoffes anzuwenden, sowohl als Faserrohstoffquelle, als auch als ökologischen Füllstoff. In diesem Vorhaben wurden drei Bioverbundkunststoff-Gruppen aus Reisstroh und organischen Polymeren entwickelt. Die technischen Eigenschaften dieser Proben wurden auf ihre Verwendungsmöglichkeit in der Architektur hin getestet und analysiert. Zunächst wurde eine Reisstrohfaserplatte mit elastischem Binder und einem Faseranteil von 80% entwickelt. Diese erwies sich von hoher ökonomischer und ökologischer Bedeutung für eine mögliche architektonische Anwendung, die bisher erhältliche Faserplatten so nicht aufweisen. In der zweiten Baustoffgruppe wurden zwei thermoplastische RS- Biokomposite entwickelt, denen Reisstroh zu 20% Gewichtsanteil eines mit Silikat angereicherten Öko-Füllstoffs beigegeben wurde, um es als brandhemmendes Additiv im Zusammenwirken speziell mit Biokunststoff bewerten zu können. Biokomposite mit RS-PLA und RS-Lignin zeigten erhöhte Flammbeständigkeit aufgrund des 20%igen Fasergewichtsanteils. Die Entflammbarkeit von RS-Lignin-Biokomposit erreichte eine andere Materialklasse, nachdem Zellulose durch Reisstroh ersetzt wurde. RS-PLA wies erhöhte Flammbeständigkeit im Vergleich zu RS-PP auf, die weit unterhalb der Klassifizierung lag. Diese Ergebnisse leisten einen neuen wissenschaftlichen Beitrag auf diesem Gebiet, was bisher so nicht untersucht wurde. Als drittes entstanden zwei RS- Bioharz-Biokomposite, in denen 20% Gewichtsanteil RS-Fasern mit zwei Bioharzsystemen gemischt wurden. Dabei verwendete man je nach Art des jeweiligen Harzes unterschiedliche Herstellungsmethoden. Es fand ein Vergleich zwischen einem entsprechend zusammengesetzten RS-Biokomposit mit auf Erdöl basierendem Harz statt. Diese Gegenüberstellung machte deutlich, dass die RS-Bioharz-Biokomposite mechanischen Belastungen nicht so gut gewachsen waren wie RS-erdölbasierte Biokomposite. Dennoch zeigten die RS-Bioharz-Biokomposite eine hohe Witterungsbeständigkeit, wenn sie pigmentiert waren. Das könnte von großer Bedeutung sein, wenn diese umweltfreundlichen Materialien für Fassaden mit komplexen geometrischen Formen eingesetzt werden. Die drei entwickelten Reisstroh Biokomposit-Gruppen zeigen weitere Anwendungsmöglichkeiten von Fasern aus landwirtschaftlichen Reststoffen in der nachhaltigen Bauindustrie. Faser verarbeitende Industrien, wie Faserplattenherstellung und Produktion geformter naturfaserverstärkter Komposite, können Strohfasern aus der Agrarproduktion als sehr ergiebige und preiswerte Rohstoffquellen nutzen. Folglich kann durch die Verbreitung von billigeren und umweltfreundlicheren Biokomposit-Produkten in architektonischen Anwendungen die GesamtC02-Biilanz verbessert und teure fossile Rohstoffe und langsam nachwachsende Holzprodukte, die noch immer den Markt bestimmen, ersetzt werden.