Bio-based Construction Research Articles

Design and validation of a selective binding 3D printer for bio-based construction materials

Design and validation of a selective binding 3D printer for bio-based construction materials

What hinders the transition towards a bio-based construction sector? A global innovation system perspective on its value chain

The construction sector is heavily polluting and an actual threat to the natural environment, therefore its transition towards becoming bio-based is imperative. This transition is currently unfolding and it is driven in particular by innovation activities taking place along the sector’s value chain. In the upstream segment, bio-based materials are being improved, while novel building techniques in the core segment enable the use of these materials. In this paper, we utilize the global innovation systems (GIS) framework to examine these innovation activities and their valuation dynamics. In particular, we investigate how the GIS of the bio-based construction sector is organized along its value chain, providing insights into the barriers to the sector's sustainability transition. Our empirical analysis, based on a rich set of expert interviews, demonstrates that the GIS configuration changes along the value chain, driven by profound differences in the innovation mode. This situation creates a bottleneck that hinders the sector's transition, where knowledge about bio-based materials developed upstream fails to translate down the value chain. However, we also find that several niche firms cover and integrate multiple value chain segments and overcome this knowledge gap, suggesting that the transition towards a bio-based construction sector could accelerate with further innovation system reconfigurations.

The risk of shifting environmental burdens in biobased construction - Life cycle assessment of a residential renovated building case study in Belgium

Abstract The construction industry is a major contributor to environmental degradation, resource depletion, and energy consumption. As global concerns about sustainability and environmental impact continue to rise, it becomes imperative to reassess the materials used in building construction. This research paper presents a comprehensive life cycle assessment (LCA) using the Belgian TOTEM tool according to EN15804+A2 for evaluating material choices in building construction with a focus on the renovation of residential buildings in Belgium. The study aims to provide a holistic understanding of the environmental implications associated with biobased construction materials enabling informed decision-making for sustainable building practices. To achieve this, we conducted an analysis of the life cycle environmental performance of biobased materials used in external walls of a renovation case study project and compared it to common built-up scenarios of conventional construction materials applied in the same case study. The research results show that using biobased materials for renovation can significantly reduce embodied GHG emissions but can lead to burden shifting such as resulting in an increased impact on land use, particulate matter emissions, depletion of abiotic resources and eco-toxicity. The study not only underscores the importance of comprehensive cradle-to-grave life cycle thinking but also provides valuable insights for stakeholders in the construction industry.

Biobased Construction from Agricultural Crops: Paper 1 - A State of Play of Commercial Solutions in Europe

In response to environmental concerns and the global warming issue in particular there is a growing drive to decarbonise the building sector and transition it to more circular practices. Biobased construction materials, products and systems are an important low carbon and circular strategy as they can enable low to negative carbon construction and have strong circularity advantages notably being able to enter the bio cycle, using renewable, low to zero toxic resources and provide a range of other performance benefits, including moisture and vapour regulation. This novel research presents a unique state of play on the commercial application of biobased construction from selected agricultural crops, straw, miscanthus and hemp, focused on the European context. A desk-based review of known biobased material producers and manufacturers is undertaken, supplemented with semi structured interviews and site visits, to provide a comprehensive overview of the sector and detailed account of the types of biobased materials, products and systems that are being applied in buildings across Europe and beyond. The findings show that a diversity of agricultural crops are being utilised at different process, manufacture and construction technology levels, providing a range of tested and certified materials and products for application in mainly timber frame construction, but also some masonry solutions, and a growing number of modular systems. These operate in a diversity of supply chains and are being applied in a wide range of building types, both domestic and non-domestic, including multi story and complex buildings.

Life cycle assessment and design of LignoBlock: A lignin bound block on the path towards a green transition of the construction industry

Lignin-based biopolymer-bound soil composites (BSCs) are a new class of sustainable construction materials that utilize a bio-based biopolymer — lignin — as a binder. Prior use of lignin suggests that lignin is a promising candidate for the development of bio-based construction materials. Inspired by these applications, lignin-based BSCs were developed using lignoboost lignin, lignoforce lignin, alkali lignin, and hydrolysis lignin. Uni-axial compressive testing of lignin-based BSC shows that the compressive strength for these BSCs range from 1.6–8.1 MPa, which makes them appropriate for low compressive strength construction applications. We performed a life cycle assessment (LCA) of lignin-based BSC, with the functional unit being a CMU-sized block (V=6423cm3). The major advantage of BSC lies in the elimination of ordinary portland cement, which is common to many construction materials, including many forms of concrete. Furthermore, the use of lignin in lignin-based BSC results in carbon sequestration (lignin ≈ 60 wt% carbon), potentially making construction materials made from lignin-based BSC carbon negative. Additionally, a design guide for estimating the life cycle carbon footprint of lignin-based BSC for a required compressive strength was developed. By utilizing the results from material tests and the LCA, designers are now able to use lignin effectively in construction applications, as they can now design lignin-based BSC for a target compressive strength with a full understanding of the life cycle carbon footprint implications.

Thermo-Acoustic Properties of Four Natural Fibers, Musa textilis, Furcraea andina, Cocos nucifera, and Schoenoplectus californicus, for Building Applications

Natural and bio-based construction materials such as bamboo, cork, or natural fiber composites offer a promising solution for enhancing the environmental sustainability of buildings. In this sense, the paper presents an experimental thermo-acoustic characterization of four common Ecuadorian natural fibers, abaca (Musa textilis), cabuya (Furcraea andina), coir (Cocos nucifera), and totora (Schoenoplectus californicus). Different densities were considered, from 85 kg/m3 (Cabuya) to 244 kg/m3 (totora), to thermo-acoustically characterize the samples built with these fibers, by means of the guarded-hot-plate (GHP) and impedance tube methods in-lab experimental benches. The exhaustive original characterization of the evaluated natural fiber composites showed a promising overall thermo-acoustic behavior. The thermal conductivity of the fibers was around 0.04–0.06 W/m·K and, therefore, comparable to other materials such as polystyrene, polyurethane, or aerogel that are already utilized for similar applications. On the other hand, the sound-absorption properties of the evaluated fibers are also very competitive, but strongly affected by the thickness of the sample, with noise reduction coefficient NRC ranging from 0.12 to 0.53. Consequently, the production and distribution of these materials in the Ecuadorian market for thermal insulation and acoustic conditioning constitute an alternative characterized by good technical performance, which, compared to synthetic composites used in the construction industry for similar duties, is ecological, sustainable, and has low built-in energy consumption.

Modeling of glubam roof truss, parameter identification and updating based on parallel genetic algorithm

This research introduces an innovative approach to the design and simulation of bio-based laminated structures, specifically focusing on glue-laminated bamboo (glubam) used in roof trusses. Our study fills a critical gap by investigating the mechanical behaviors of bolted connections in bamboo-based structures, which have not been comprehensively studied before. We employ a dual-phase methodology: initially, cyclic tests on bolted steel to glubam joints assess their hysteretic behavior, followed by tests on glubam planar roof trusses to evaluate structural responses under practical conditions. Our novel contribution is the development of a simplified mechanical-based hysteretic model, incorporating connector and spring elements in series or parallel within the ABAQUS software. This model significantly improves on existing models by allowing for initial calibration through a parallel genetic algorithm (PGA), enhancing both accuracy and efficiency. Subsequent incorporation of this model into the simulation of truss joints enabled the creation of an advanced hybrid roof truss model within ABAQUS. The final stage of our research demonstrates the application of a PGA-based model-updating framework, which substantially increases the model’s predictive accuracy. This work not only advances the understanding of structural behavior in bio-based construction materials but also introduces a robust framework for model updating that can be applied to other engineering simulations, contributing to more sustainable and resource-efficient construction practices.

Bio-based connections and hybrid planar truss: A parallel genetic algorithm approach for model updating

Bolted steel to laminated bio-based material connections experience significant performance challenges due to the nonlinear response and high stress concentrations at their joints. This paper introduces an innovative 3D plasticity-fracture continuum Finite Element (FE) model that significantly advances the simulation of such truss joints by integrating Hill's yielding criteria with an element removal methodology for fracture simulation. This novel approach captures both plastic and fracture behaviors simultaneously, a capability not sufficiently addressed in existing models. We detail the theoretical framework for these models, including the derivation of constitutive equations and the algorithms necessary for their implementation in ABAQUS. Additionally, it is provided a low-fidelity modeling of truss joints, offering a comprehensive analysis of connector elements, joint models, and parametric modeling via Python scripting. The model's efficacy is demonstrated through identification of connection and of hybrid planar trusses under cyclic loading, which validates the practical applicability of the method. To optimize computational efficiency, we developed a Parallel Genetic Algorithm (PGA) that integrates seamlessly with ABAQUS and Python to facilitate parameter calibration. This integration not only enhances the model's accuracy but also reduces computational load, making it feasible for complex engineering applications. Our findings illustrate a significant improvement in modeling accuracy and efficiency, establishing a robust methodology for analyzing truss joints in bio-based construction materials.

Fast-Growing Bio-Based Construction Materials as an Approach to Accelerate United Nations Sustainable Development Goals

The United Nations Sustainable Development Goals (UN SDGs) ensure future human well-being. However, they face challenges due to the pressing need to reduce carbon emissions, with nearly 40% originating from the construction sector. With the current global environmental and energy crisis, there is a pressing need to address building carbon emissions and prioritise investments in passive strategies for improving indoor thermal comfort. Exploring fast-growing bio-based materials like bamboo, straw, hemp, and flax directly addresses these concerns, fostering environmental sustainability. Material selection in construction is crucial for advancing the SDGs, for example, promoting sustainable cities and communities (SDG11) and responsible consumption and production (SDG12). This paper proposes a comparative analysis of conventional and bio-based construction materials, focusing on their production stages through life cycle analysis. Tools such as Building Emissions Accounting for Materials (BEAM) and the Methodology for Relative Assessment of Sustainability (MARS) enable a detailed comparison. The results highlight the benefits of bio-based materials in storing carbon more rapidly and their lower environmental impact compared to conventional alternatives. Moreover, bio-based materials contribute to indoor moisture regulation and a healthier indoor environment, underscoring their potential to accelerate progress towards the UN SDGs through informed material choices in design practices.

Enhancement of Flexural Strength in Fiber–Cement Composites through Modification of Sisal Fiber with Natural Rubber Latex and Expanded Perlite

This study presents a novel approach in enhancing the flexural strength of sisal fiber cement composites by employing a dual coating technique with natural rubber latex and expanded perlite to the sisal fibers. The effects of different fiber content (0.25, 0.5, 0.75, 1, 1.25, and 1.5 wt%) and fiber length (1, 2, and 3 cm) on the physical and mechanical properties of sisal fiber cement were also studied. The physical properties, including bulk density and water absorption, were evaluated via the Archimedes method. Flexural strength was measured using the 3-point bending method, and microstructure was observed using a scanning electron microscope (SEM) and an optical microscope (OM). As the fiber content and length increase, the bulk density of the sisal fiber cement decreases. However, composites utilizing coated fibers consistently exhibit a higher bulk density than those utilizing uncoated fibers, attributed to enhanced adhesion and reduced porosity. The water absorption of sisal fiber cement increases with fiber content, but it is mitigated by the natural rubber latex coating, which prevents fiber–water absorption, and by expanded perlite, which reduces voids in the matrix. Composites containing coated fibers consistently exhibit superior flexural strength compared to those with uncoated fibers. The highest flexural strength values of 5.58 MPa were observed in composites utilizing 3 cm of coated fiber with 0.25 wt% fiber content. Microstructure analysis reveals a well-bonded interface in coated fibers, emphasizing the positive impact of coating on mechanical performance. The incorporation of coated sisal fibers effectively improves adhesion, water resistance, and flexural strength, offering sustainable and durable construction materials. The achieved results can serve as the guidelines for the development of a high-performance bio-based construction materials with improved durability and reduced environmental impact.

Recent Advances in Bio-Based Concrete Materials: A Critical In-Depth Review

With the growth of the construction industry, the role and importance of sustainable construction practices are also increasing. This study reviews the various advancements in the field of bio-based construction materials, including bio-aggregates, bio-binders, and bio-bricks. The origins of our centuries-old construction methods can be found in bio-based concrete materials, which have been revived and modernized to meet the needs of present-day construction. The integration of recovered construction and agricultural wastes plays a significant role in bringing these materials into the competitive building sector, aligning with sustainability goals. This study provides an in-depth examination of the processes and compositions required to achieve the desired strength and durability of bio-based materials. By comprehensively analyzing global research data, this study offers insights into the successful incorporation of biomaterials, emphasizing their potential to reduce carbon emissions and promote the responsible utilization of natural raw materials. This pathway moving toward more sustainable construction practices underscores the environmental benefits of bio-based concrete materials.

Characterisation of Bio composites for Bio-Manufacturing: Jute-reinforced Bacterial Cellulose for Construction

This research investigates the biological, mechanical and thermal characterisation of the jute-reinforced bacterial cellulose biocomposites to forecast their potential and performance in bio-manufacturing for architectural construction. The experimental trial-and-error-based methodology involves seven stages: Material formulation, manufacturing of biocomposite samples, mechanical testing, scanning electron microscopy analysis, thermogravimetric analysis, and biodegradation assessment. The results indicated that the use of biobased construction materials has a potential to reduce carbon footprint, while the addition of jute fibres resulted in enhanced mechanical properties such as higher elasticity and desirable stiffness compared to pure bacterial cellulose. Moreover, slight distinctions in thermal property analysis and biodegradation assessments across the specimens are observed. The findings contribute valuable data for material selection, design optimization, and structural considerations in the integration of these biopolymers into construction practices. Overall, this research aligns with the broader objective of advancing ecological construction starting from the material formulations, thus addressing the scalability of these materials, considering their potential for large-scale adoption in the construction industry.

A Review on Recent Research on Bio?Based Building Materials and their Applications

Abstract: Bio-based materials represent a promising alternative in building envelope applications, with the aim of improving inuse energy efficiency. They have the advantage of being renewable, low embodied energy and CO2 neutral or negative. In addition, they are excellent thermal regulators. This paper presents an overview of the state-of-the-art of bio-based materials used in building construction and their applications. The materials outlined include hemp, wood, date palm wood, cork, alfa and straw. Through this literature study we want to get a broad overview of the current state of theoretical and experimental studies of their hygrothermal characteristics and their thermal and energy performances. The aim is not to be exhaustive but to summarise the most important research results on these materials. This is the first part of a research work that deals wit h the contribution to the development of a new bio-based construction material to be used in building.

Unveiling moisture transport mechanisms in cellulosic materials: Vapor vs. bound water.

Natural textiles, hair, paper, wool, or bio-based walls possess the remarkable ability to store humidity from sweat or the environment through "bound water" absorption within nanopores, constituting up to 30% of their dry mass. The knowledge of the induced water transfers is pivotal for advancing industrial processes and sustainable practices in various fields such as wood drying, paper production and use, moisture transfers in clothes or hair, humidity regulation of bio-based construction materials, etc. However, the transport and storage mechanisms of this moisture remain poorly understood, with modeling often relying on an assumption of dominant vapor transport with an unknown diffusion coefficient. Our research addresses this knowledge gap, demonstrating the pivotal role of bound water transport within interconnected fiber networks. Notably, at low porosity, bound water diffusion dominates over vapor diffusion. By isolating diffusion processes and deriving diffusion coefficients through rigorous experimentation, we establish a comprehensive model for moisture transfer. Strikingly, our model accurately predicts the evolution of bound water's spatial distribution for a wide range of sample porosities, as verified through magnetic resonance imaging. Showing that bound water transport can be dominant over vapor transport, this work offers a change of paradigm and unprecedented control over humidity-related processes.

The potential of carbon storage in bio-based solutions to mitigate the climate impact of social housing development in Brazil

The increasing demand of housing in the Global South requires effective solutions to cover the corresponding deficit in the next decades. In Latin America, Brazil is the most populated Nation, which accounts for one-third of the total population and is the main contributor to carbon emissions. This study estimates how bio-based construction solutions, implemented in the Brazilian housing stock as alternative to conventional systems, can contribute to limiting the carbon emissions. Five different construction archetypes were considered, and a Material Flow Analysis model developed to estimate the demand of construction materials by 2050 under multiple scenarios. A carbon footprint assessment, which considers the dynamic effect of biogenic carbon sequestration and uptake, was finally performed to estimate the net Global Warming Potential. The results indicate that, if fast implemented, bio-concrete solutions with short-rotation vegetal species as bamboo, coupled with the lowest material intensity scenario, can reduce the cumulative carbon emissions by 65%, equal to 118 Mt of cumulative CO2-eq savings. Considering bamboo's widespread availability in Brazil's different climate zones, and in the Global South in general, such material presents a significant impact to mitigate the climate impact of social housing. However, the carbon saving intensity is largely affected by uncertainties on population growth and the type of biomass used in the concrete mixture. Therefore, further development of standards for the safe use of bio-concrete in construction is urgently needed, as well as the implementation of environmental policies to facilitate the market penetration of bio-based solutions in emerging economies.

Straw bale construction towards nearly-zero energy building design with low carbon emission in northern China

With the aim of achieving carbon neutrality, bio-based construction is of increasing interest for decarbonization globally. Among the potential candidates, straw bale is promising due to its ready availability and energy efficiency benefits. However, thermal conductivities of straw bales can vary greatly due to construction details, which may lead to failures in meeting nearly-zero energy building (nZEB) design standards in real practice. In the context, this study applied thermal property and carbon emission assessment of full-size straw bale walls (SBWs) and construction of an experimental building in northern China. The results demonstrated that the thermal conductivities of different monitoring portions of the SBWs ranged from 0.067 to 0.088 W·m−1·K−1. This resulted in U-values (0.16 W·m−2·K−1) marginally higher than the lower limits of nZEB design, indicating the importance of addressing thermal bridging issues of SBWs. The SBWs without additional insulation layers therefore can satisfy nZEB design standards in the severe cold region after certain adjustments. Besides, when not accounting for carbon sequestration, SBWs generated the lowest emissions among the schemes in meeting U-value limits for nZEB design (at least 14.6% lower than those of timber walls), with increasing emission reductions as U-value limit decreased. The results indicated that SBW demonstrated effectiveness in carbon reductions with high thermal performance. The findings of the research can facilitate application of straw bales and development of clean construction and net-zero design in northern China.

Haiti: architecture to save the soil

The use of bio-based construction materials in Haiti could help the construction sector to transition, from non-seismic unreinforced masonry structures towards materials that can reverse catastrophic deforestation, promote ecological regeneration, and help save the soil. Architecture has a role to play in this vision, by creating new designs and incentivising clients to invest in new materials.

Carbon emission-based life cycle assessment of rural residential buildings constructed with engineering bamboo: A case study in China

Engineering bamboo owning to modern industrial technology is a renewable material that holds immense potential in driving the development of building structural systems with a low carbon footprint. This study presents a life cycle assessment of a rural residential building constructed with engineering bamboo (i.e., glued laminated bamboo) from the perspective of carbon emissions. To highlight the carbon sequestration of bio-based construction material, a reinforced concrete building employed from the literature was used as a contrast scheme. The system boundary encompasses the production, transportation, construction, operation, and disposal phases, with a functional unit defined as “one square meter”. The material inventory and elements in each phase of the life cycle were collated from SimaPro and available literature or specifications. To gauge the uncertainty of carbon emissions, the Monte Carlo method was used for inventory analysis. Results of the assessment highlight that the life cycle carbon emission of the engineering bamboo-based rural residential building is 104.037 kgCO2eq/m2. The operation phase is identified as the most significant contributor to carbon emissions, followed by the production phase. The transportation, construction, and disposal phases have a relatively minor impact on emissions. The notable characteristic of engineering bamboo is its ability to sequester carbon, resulting in lower carbon emissions during the production phase. Based on the Monte Carlo simulation, the mean life cycle carbon emission for the typical rural residential buildings constructed with engineering bamboo is estimated to be 1035 kgCO2eq/m2.

Towards rural net-zero energy buildings through integration of photovoltaic systems within bio-based earth houses: Case study in Eastern Morocco

Off-grid rural electrification programs involving renewable energy provide effective ways to boost the availability of power in remote areas. Herein, the combination of local bio-based building materials with appropriate sizing of a photovoltaic (PV) system to achieve energy-efficient rural housing in developing countries is investigated. The study focused on the fabrication and laboratory testing of a building material incorporating plant fibers, followed by a feasibility analysis of an integrated stand-alone PV system. EnergyPlus software was used to assess the energy-saving potential of bio-based building envelopes, and Homer Pro software was used for techno-economic optimization. Using a case-study building, various configurations were evaluated in terms of levelized energy cost and net present cost. According to the experimental results, the inclusion of 8 wt% Alfa fibers in earth blocks led to a noteworthy enhancement in the thermal resistance and time lag of the building envelope. Specifically, the improvement ranged from 0.549 to 1.125 m2K/W and from 18.5–h to 23.2–h, respectively, compared to using earth alone. This improvement resulted in a substantial decrease in the building's annual energy consumption, with a reduction of 24.3% for heating and 26.7% for cooling. Furthermore, the techno-economic analysis revealed that the electricity provided by a PV-battery hybrid system was 100% renewable and emission-free, with an energy cost of approximately $0.218/kWh and a present net cost of $11,560.21 These findings indicated that combining available solar energy with locally produced bio-based construction materials could be a viable approach for achieving carbon neutrality and building energy-efficient ulta-low-cost rural housing.

Upscaling bio-based construction: challenges and opportunities

ABSTRACT Construction projects using emerging bio-based materials have been realized over the past ten to fifteen years within Europe. Bio-based buildings utilize properties of natural materials to regulate internal environments, particularly fluctuations in temperature and relative humidity. Despite individual exemplar projects demonstrating functional performance and long-term operational cost savings, there hasn’t been a proliferation of commercial or domestic bio-based projects. With a growing shift towards circular economy construction, bio-based buildings could be readily adopted to meet this development. This study evaluates barriers faced by bio-based materials, making the upscaling of production and a breakthrough into mainstream construction challenging. Evaluation was achieved through senior professionals with experience in bio-based construction participating in semi-structured interviews based on core categories of finance, knowledge, and policy. Challenges include the upscaling of production by manufacturers of emerging materials, inconsistencies in life cycle assessment, material certification and accreditation, vested interests in the construction industry, and concerns regarding initial costs, availability, and knowledge of products. Potential solutions for upscaling bio-based construction are identified and include increased case studies, positive legislation, regional economic regeneration, the wellness agenda, long-term economic sustainability, and engagement with established construction companies. This insight has informed the procurement process, material evaluation, and adoption of policy.