Wood-based Building Materials Research Articles

A comparative assessment of the capabilities and success of the wood construction industry in Slovakia and Ukraine based on life cycle assessment certification standards

This study assessed the possibility of using wood as a building material for the construction of houses. A comprehensive method was used, which consisted of analysing environmental management regulations, applying the life cycle assessment method to minimise the carbon footprint; using software to calculate the carbon footprint of a wooden house at different stages of the life cycle. The object of study is the carbon footprint of a house built of wood. The Life Cycle Assessment method was used as a methodology for assessing the life cycle. Using the One Click Life Cycle Assessment and Life Cycle Cost software, the carbon footprint of a log house was calculated for the product life cycle stage mentioned above (A1-A3). When calculating the carbon footprint of wood-based building materials, carbon emissions were taken into account not only from the finished products, but also from all other products obtained as a result of logging. When calculating the carbon footprint, greenhouse gas emissions from all activities are estimated. We have obtained data on the life cycle cost of a wooden house in terms of electricity use. Accordingly, we obtained a value of global warming potential (A1-A3) of 0.51 kg CO2 e/kWh. We also obtained data on the life cycle cost of a wooden house in terms of diesel consumption. According to the results of the LCA, the value of the global warming potential due to meeting the water supply/sewage needs is (A1-A3) 0.69 kg CO2 e/m3. The value of the global warming potential due to meeting the heat supply needs of production needs is (A1- A3) 0.13 kg CO2 e/kWh. Based on the information obtained, we can conclude that it is advisable to use a wooden log house as a building material, as the carbon footprint is smaller than that of a brick building. The final section presents the results of calculating the life cycle cost of a wooden house by discount factor and inflation, the results of the life cycle cost of a wooden house by percentage of energy costs, and the results of assessing the life cycle cost of a wooden house (displaying parameters according to the European energy certification scale). Based on the carbon footprint assessment (using the Life Cycle Assessment methodology), economic comparison (Life Cycle Cost and total construction costs), and expert assessment (based on technical and ergonomic parameters) of the two construction technologies, the feasibility and possibility of using wood as a building material was established. The study proves the feasibility of applying the LCA method in the construction industry.

Experimental evaluation of combustion performance in the three main anatomical sections of poplar wood

ABSTRACT The interrelationship and organization between the axial and transversal systems gives rise to three main views, namely cross, radial and tangential sections. This study investigated the differences in combustion properties of the three main anatomical sections of poplar wood and explains the reasons for the differences regarding wood microstructure, pore structure, heat conduction, and microstructure after heat treatment. The thermal conductivity of poplar wood in the cross-section (Wood-CS) was 0.1864 W/m. K, exceeding those of the radial (Wood-RS) and tangential sections (Wood-TS) by 47% and 38%, respectively. In the cone calorimeter test (CC), the peak heat-release rate (pHRR) of Wood-CS samples was 92% and 73% higher than those of the Wood-RS and Wood-TS samples, respectively. This is attributed to the differences in microstructures and the occurrence of macropores in different anatomical sections. This study explored the combustion performance and mechanisms of wood samples in the three main sections, providing crucial theoretical insights for flame retardant impregnation levels in treating wood and aiding in the selection of fire-resistant wood-based building materials.

The architect’s material palette

During the twentieth century, reinforced concrete acquired a status of a leading building material. Its wide application influenced the construction technologies and the layout of cities and largely shaped the aesthetics of modernism. At the beginning of this century, the cost of cement and concrete production is showing rapid growth, and the environmental burden from cement production is becoming increasingly unacceptable. Economic and environmental factors force us to look for a replacement for reinforced concrete. In particular, there is renewed interest in wood-based building materials. The problem is that the dominance of concrete has formed a stable orientation of architects to a specific set of properties – isotropy, high density, fire safety, and so on, which are absent from wood. A compromise option is cross-laminated timber (CLT), which at the same time has its own disadvantages and limitations. The article concludes that it is necessary to diversify the palette of building materials and develop special training programs for architects to work with a wide range of building materials.

Methodological aspects in assessing the whole-life global warming potential of wood-based building materials: comparing exterior wall structures insulated with wood shavings

Due to the heavy environmental impacts on the building industry, wood-based building materials are gaining interest. They may improve the indoor climate and have a low carbon footprint compared to steel and concrete structures. This study provides knowledge on the carbon footprint of wood shavings (WSs) and WSs improved with clay as insulation materials. The study defines the lifecycle emissions of five different wall structures, of which two are of conventional type in the Finnish context and three with WSs as insulation. The study follows the EN standards on buildings’ life cycle assessment with a streamlined approach and discusses the applicability of the method in the normative context. The study analyzes multiple methodological aspects, including biogenic carbon, co-product allocation, and defining the functional unit in wall structure comparison. In the base case, the exterior wall using WS as insulation provided the lowest GHG emissions of the compared structures. The study finds global warming potential (GWP) of WSs moderately sensitive to allocation choices and energy sources used in the drying of WSs with clay, while the End-of-Life treatment option can radically change the results in biogenic GWP. From the perspective of applying the buildings’ life cycle assessment in the normative context, there is a call for further research for controlling uncertainties in modeling End-of-Life options of biogenic materials.

A high-strength bonding, water-resistance, flame-retardant magnesium oxychloride cement based inorganic adhesive via the construction of supramolecular system

Magnesium oxychloride cement (MOC) adhesive has the advantages of being non-formaldehyde and flame retardant and having low energy consumption; however, its poor compatibility with the wood interface results in low bonding strength. Inspired by the H-bonded β-sheets nanoconfinement phase of spider silk, a high-performance inorganic adhesive was developed based on the supramolecular network system of poly (vinyl alcohol)/phytic acid (PVA/PA) with dissolved ions and the synchronous hydration process of MOC. Benefiting from the H-bond crosslinking and chelation confinement effects, the addition of PVA/PA enables MOC to penetrate steadily into the wood. Under this strategy, the compressive strength and softening coefficient of the modified MOC adhesive were 65.07 MPa and 0.84, which were 17.03% and 425% higher than the unmodified MOC adhesive, respectively. In addition, the MOC/PVA/PA adhesive achieved a wet shear strength of 2.02 MPa, 68.3% higher than that of the MOC adhesive. These results demonstrate that the MOC/PVA/PA adhesive would be a promising inorganic adhesive in wood-based building materials.

Water vapour transmission properties of uncoated and coated wood-based panels

ABSTRACT Knowing the properties of wood-based building materials is essential for their proper use. Moisture transfer properties of building materials are crucial to proper building design and the prevention of moisture-related problems. In selecting materials for the building, it is important to know their water vapour transmission properties. In this research the water vapour transmission properties of uncoated and coated particleboard, oriented strand board (OSB) and birch plywood were studied using wet cup method and a moisture gradient in the samples was additionally measured. The water vapour transmission rate of free films of three commercial transparent coatings was also studied. Results showed that particleboard had the highest water vapour permeability and that the coatings reduced the water vapour permeability of all tested wood-based panels. Moreover, sanding increased the water vapour permeability of uncoated particleboard and OSB. The moisture gradient in all tested wood-based panels was linear. The highest water vapour transmission rate was recorded for acrylic water-borne coating, followed by polyurethane water-borne coating and the lowest for polyurethane solvent-based coating.

Moisture Dynamics of Wood-Based Panels and Wood Fibre Insulation Materials.

Moisture performance is an important factor determining the resistance of wood-based building materials against fungal decay. Understanding how material porosity and chemistry affect moisture performance is necessary for their efficient use, as well as for product optimisation. In this study, three complementary techniques (X-ray computed tomography, infrared and low-field NMR spectroscopy) are applied to elucidate the influence of additives, manufacturing process and material structure on the liquid water absorption and desorption behaviour of a selection of wood-based panels, thermally modified wood and wood fibre insulation materials. Hydrophobic properties achieved by thermal treatment or hydrophobic additives such as paraffin and bitumen, had a major influence on water absorption and desorption rates. When hydrophobic additives did not play a role, pore distributions and manufacturing process had a decisive influence on the amount and rate of absorption and desorption. In that case, a higher porosity resulted in a higher water absorption rate. Our results show that there is a clear potential for tailoring materials towards specific moisture performance by better understanding the influence of different material characteristics. This is useful both for achieving desired moisture buffering as well as to increase service life of wood-based materials. From a sustainability perspective, fit-for-purpose moisture performance is often easier to achieve and preferred than wood protection by biocide preservative treatments.

Serviceability limit state model for fungal growth on wood materials in the built environment

Fungal (mould) growth in wood based building components could have significant detrimental effects on the operational and structural requirements of the built environment. Quite naturally, building designers and material scientists are keen to predict mould growth in wood and wood based building materials. Available surface mould growth models primarily predict the levels of mould growth in different environmental and material conditions. However, modern design practices allow acceptable limit of risk in the design process. Hence, a probabilistic mould growth model is required which takes into account risk tolerance thresholds for mould growth. This paper presents a research initiative that shifts the mould growth narrative from predicted levels to probabilistic predictions, which is the foundation block associated with limit state design approach, widely used in structural design codes and standards. More specifically, this paper presents a serviceability limit state mould growth model for wood using jack pine (Pinus banksiana) wood and the fungal species Penicillium chrysogenum. The outputs from this model were verified using the results obtained from an experimental roof study that investigated the impacts of different surface treatments on mould growth in ventilated roofs.

Sustainability impact assessment of glue laminated timber and concrete-based building materials production chains – A Lithuanian case study

In recent years, wood has received increased interest in Europe as a multi-storey building material. The trend is driven by the recognition that wood, as an environment friendly material, can contribute bioeconomy development and the achievement of sustainable development goals. In Lithuania, multi-storey wood-based building is still at the level of policy and political discussions. Therefore, the presented research focuses on quantification and comparison of the sustainability impacts of both wood- and concrete-based building materials value chains and provides applied scientific knowledge relevant to decision makers and in this way contributes to mitigation of the climate change.In detail, study covers the production value chain – from raw material extraction to manufacturing using the same method, while documenting and assessing the material sourcing stages transparently and consistently. In our study glue laminated timber and sawn timber building materials represented renewable material value chains, while site-cast concrete and precast reinforced concrete building materials represented non-renewable materials value chains. In discussion with study partners in the BenchValue project and during a project stakeholder workshop, twelve environmental, social and economic indicators were selected to perform the sustainability impact assessment of selected building materials. Building materials were compared by using a decision support tool ToSIA. The relevant data was gathered from local, well-known companies in the national and international arena.Our results revealed that glue laminated timber and sawn timber value chains compared to site-cast concrete and precast reinforced concrete value chains have more positive sustainability impacts. This is especially true when analysing environmental indicators: GHG emissions, Energy use, Generation of wastes and Water use. Analyses also revealed more positive socio-economic impacts of wood-based building materials. The socio-economic advantage of wood could increase competitiveness of the regions and contributes to their sustainable development.Our paper is in line with the applied research. Since it is a case study, the presented results are country specific, because the estimation of indicators was done by applying local data. The presented research is relevant to policy experts and decision makers in the context of the reduction of CO2 emissions. Also, this paper is relevant to the companies and architects who want to build and compare various building materials. Partially, results of this paper could be applied in other countries with comparable to Lithuania economic development level, having in mind the possible shortcomings already highlighted.

Influence of weathering on surface roughness of thermally modified wood

Wood is one of the most important building materials. Thermally modified wood is entering the market and replacing wood preservatives and tropical wood species in some applications. Thermally modified wood is exposed to weathering similarly as other wood-based building materials. It has been reported that if thermally modified wood is exposed to weathering, its moisture performance might decrease fairly fast. Moisture performance reflects the material’s ability to remain dry and dry out fast when wet. The aim of this study was to determine whether this phenomenon is associated with crack formation or roughness. Norway spruce, thermally modified spruce, wax-treated thermally modified spruce, and European larch heartwood samples were exposed to artificial accelerated weathering and natural weathering for 9, 18, and 27 months. Samples were subsequently isolated, and their roughness was determined with a confocal laser scanning microscope on axial and longitudinal surfaces at 10× and 50× magnification. After weathering, roughness increased on both axial and longitudinal surfaces. This was evident from the profile 2D measurements (Ra) and surface 3D measurements (Sa). The effect of natural weathering on roughness was higher than artificial accelerated weathering, presumably due to synergistic effects of abiotic and biotic factors. This may be associated with Wenzel’s theory on the influence of roughness on the contact angles of water on the surface; namely, increased roughness will decrease the contact angle on hydrophilic surfaces.

Перспективы развития высотного деревянного домостроения в России на примере зарубежного опыта

Wood-based building materials meet the basic requirements of environmentally friendly construction, which is becoming increasingly important in the modern world. However, until recently, they were rarely used in high-rise construction in Russia. CLT became a revolutionary technology, it has proven itself in countries such as Switzerland, Norway, the U.S. and others. In Russia, it has not yet found widespread use, and CLT-panels are in demand only at the market of individual housing construction. Nevertheless, taking into account the positive foreign experience can be an example and become an incentive for more active implementation of modern environmentally friendly materials and technologies in Russia. The aim of the article is to study the possibilities of high-rise wooden house building in Russia based on world practice.

VOC and carbonyl compound emissions of a fiberboard resulting from a coriander biorefinery: comparison with two commercial wood-based building materials.

Indoor air quality is a major public health issue. It is related to the choice of construction materials and associated with VOC emissions. Two wood-based commercial panels were tested: a medium-density fiberboard (MDF) and a chipboard (CH), and they were compared to a material produced from a coriander biorefinery (COR). Indicators chosen to compare the materials were physical properties (density, bending properties, surface hardness, thickness swelling, and water absorption) and VOC emissions. Emissions were evaluated in an environmental chamber at 23°C, 31°C, and 36°C, and during 28days. Carbonyl emissions on day 1 at 23°C were 74, 146, and 35μgm-2h-1, respectively, for MDF, CH, and COR. Terpenic emissions were 12, 185, and 37μgm-2h-1, respectively. Higher temperature resulted in higher emissions which decreased over time, except for formaldehyde. VOC emissions depended largely on material and temperature. Formaldehyde emission was 300 to 600 times lower for coriander boards (< 0.2μgm-2h-1), making them significantly more environmentally friendly materials in comparison with MDF and chipboard. These results highlight the interest of coriander by-products as raw materials for producing fiberboards with low impact on indoor air quality.

Models for assessment of volatile organic compound diffusivities in leather or leather imitates by mercury intrusion porosimetry test

Recent studies have been conducted on the characteristics of volatile organic compound emissions; most of them are focused on wood-based building materials, scarcely mentioned about leather or leather imitates. The volatile organic compound emissions of these products may cause poor indoor (vehicle cabins included) air quality. This article takes formaldehyde as an example to study its diffusion in leather. The porous structure of leather was characterized by carrying out mercury intrusion porosimetry test. The formaldehyde diffusivities in leather was assessed by Blondeau et al.’s, Ataka et al.’s, and Xiong et al.’s models which represent parallel, equivalent, and series interconnection of pores, respectively, and validated through independent liquid inner tube diffusion film emission experiments. The results demonstrated that the fractal dimension of leather is 2.19, which indicated it is a porous medium with self-similar pore structure. Most of the pores in leather were macro pores with average diameter 16.56 μm which contributed to 95.9% of whole porosity and the meso pore with average diameter 0.60 μm which contributed to 4.1%. As far as the liquid inner tube diffusion film emission experiment shows, the Xiong model agrees much better with the experimental results than the other two. The two kinds of pores were considered to be serially connected. It is useful for predicting volatile organic compounds diffusion coefficient in a short time and can be applied to the design and development of low volatile organic compound emission leather or leather imitates within further research.

The use of wood construction materials as a way of carbon storage in residential buildings in Brazil

Wood-based building materials are environmentally advantageous because of their lower greenhouse gas (GHG) emissions during manufacturing and capability of storing carbon permanently in their structure. The use of these materials can contribute for reaching the construction industry 2030 international goal of having carbon neutral buildings. Using carbon uptake estimation models, for these materials, improves the accuracy of GHG emissions quantification by construction industry and promotes the forestry sector. In this paper, the amount of carbon stored in wood materials is compared to amount emitted by the construction of residential apartments using traditional materials in Brazil. A sample of five apartments, representative of Brazilian typical construction scenarios, was analyzed, and the amount of carbon stored in wood products (such as doors, floors and ceiling linings) calculated. The impact of stored carbon n CO2eq (carbon dioxide equivalent) emission figures was assessed. The study shows that the stored carbon accounts, on average, for approximately 10% of the total CO2eq emitted during the construction.

Technical Note: Lateral Connections and Withdrawal Capacity of Western Juniper

The goal of this project is to increase the amount of available information about western juniper wood to encourage its use in structural applications. This project evaluated the performance of connections involving western juniper wood and other common wood-based building materials. The tests for this project included edge lateral nail connection tests (ASTM 2007a), dowel bearing strength tests (ASTM 2007c), and withdrawal tests (ASTM 2007b). The performance of juniper and juniper-oriented strand board (OSB) connections were characterized. The results were also evaluated against predictive design equations found in the National Design Specification (NDS). The data obtained in this study suggest that NDS equations conservatively predict the load-carrying capacity of a juniper-OSB connection but consistently predict the failure mode.

난연특성을 가지는 EVA/Intumescent/나노클레이 복합재료 제조 및 교호집성재(Cross Laminated Timber) 적용 기술

최근 들어 늘어나고 있는 도시형 화재 사고와 건축 외장재에 따른 화재 피해 사례의 증가에 따라 난연처리기술의 중요성이 부각되고 있다. 특히, 목재를 기반으로 한 건축재료의 활용에 있어서 난연처리기술은 더욱 중요하게 평가되고 있다. Intumescent 시스템은 비할로겐계 난연처리기술의 하나로, 발포와 탄화층 형성을 통하여 난연성을 구현하는 시스템이다. 본 연구에서는 Intumescent 시스템을 적용하기 위해 Ethylene vinyl acetate (EVA)를 매트릭스로 채용하여 복합재료를 제조하였다. Intumescent 시스템의 난연특성을 강화하기 위해 나노클레이를 함께 적용하였다. Intumescent 시스템과 나노클레이 기술을 함께 적용한 복합재료를 시트상의 시험편으로 가공한 후, 이를 활용하여 표면의 난연특성이 강화된 새로운 구조의 교호집성재를 제작하였다. Intumescent 시스템을 적용한 복합재료의 연소특성 평가에서 최대 열방출량이 효과적으로 감소되는 것을 확인할 수 있었다. 표면에 부착된 구조에 따라 CLT는 두 단계에 걸친 연소 현상이 발생했다. 또한, 심부 연소 과정에서 최대 열방출률이 크게 감소하는 경향을 확인할 수 있었다. 이러한 특성은 목재의 연소과정에 있어 연소 확산지연효과가 있을 것으로 판단된다. 표면단판에 대한 난연처리기술 및 복합재료 적용 최적화 기술을 통해 보다 화재특성이 개선된 CLT 구조체 개발이 가능할 것으로 기대된다. Recently, the importance of flame retardation treatment technology has been emphasized due to the increase in urban fire accidents and fire damage incidents caused by building exterior materials. Particularly, in the utilization of wood-based building materials, the flame retarding treatment technology is more importantly evaluated. An Intumescent system is one of the non-halogen flame retardant treatment technologies and is a system that realizes flame retardancy through foaming and carbonization layer formation. To apply the Intumescent system, composite material was prepared by using Ethylene vinyl acetate (EVA) as a matrix. To enhance the flame retardant properties of the Intumescent system, a nano-clay was applied together. Composite materials with Intumescent system and nano - clay technology were processed into sheet - like test specimens, and then a new structure of cross laminated timber with improved flame retardant properties was fabricated. In the evaluation of combustion characteristics of composite materials using Intumescent system, it was confirmed that the maximum heat emission was reduced efficiently. Depending on the structure attached to the surface, the CLT had two stages of combustion. Also, it was confirmed that the maximum calorific value decreased significantly during the deep burning process. These characteristics are expected to have a delayed combustion diffusion effect in the combustion process of CLT. In order to improve the performance, the flame retardation treatment technique for the surface veneer and the optimization technique of the application of the composite material are required. It is expected that it will be possible to develop a CLT structure with improved fire characteristics.

A Study on the Necessity of Complex Hazard Assessment for Combustion Products of Wood-Based Building Materials

A Study on the Necessity of Complex Hazard Assessment for Combustion Products of Wood-Based Building Materials

The Evaluation of the Flame Retardant Performance of the Wood-based Building Materials Applied to Carbon Materials

The Evaluation of the Flame Retardant Performance of the Wood-based Building Materials Applied to Carbon Materials

A large-scale test set-up for measuring VOC emissions from wood products under laboratory conditions in simulated real rooms

Abstract A large-scale test set-up was designed to evaluate the volatile organic compound (VOC) emissions of building materials in a real room situation but under laboratory conditions. Two model rooms (ModR) with a volume of 30 m3 each were constructed of the wood-based building materials X-lam and OSB, respectively. Temperature and relative humidity (RH) inside the ModR were kept in a range of 21°C–25°C and 45%–55% RH. VOCs were collected at 13 different times over a period of 23 weeks, and the total VOC (TVOC) concentration was calculated from GC/MS data. Results were quantified as toluene equivalents (TE). In the X-lam-ModR, the TVOC concentration decreased by 64% over the whole measurement period from 115 to 41 μg m-3 TE. Terpenes were the most abundant substance group and accounted, on average, for 80% of the TVOC concentration. In the OSB-ModR, the TVOC concentration decreased by 72% from 443 to 124 μg m-3 TE. Aldehydes showed the highest concentrations, accounting, on average, for 52% of the TVOC, while 38% were terpenes. The results show that this type of test provides realistic data for the praxis.

Sodium metabisulphite as a scavenger of air pollutants for wood-based building materials

This paper reports on different applications of sodium metabisulphite as a formaldehyde scavenger. The reduction in formaldehyde emission and the effect on physicomechanical properties of particleboards were studied. The scavenger was mixed with urea–formaldehyde resins with different formaldehyde to urea molar ratios and added separately in the production of particleboards. Several differences between the formaldehyde content and physicomechanical properties of boards were found. When applied to melamine–formaldehyde resins, the changes in formaldehyde emission were less significant, probably due to the incorporation of sodium bisulphite in polymeric matrix. The type of formaldehyde-based resin and the form of scavenger addition are the major factors affecting formaldehyde scavenging efficiency.