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Assessing the nutrient value of bio-based materials in relation to early fungal growth
2017 - IRG/WP 17-20631
Bio-based materials are gaining importance in the building industry, as the focus on sustainability and life-cycle-assessment has increased dramatically over the last decade. Wood and wood-engineered products as well as insulation materials made from flax, hemp, etc. are hence increasingly used. These materials originate from renewable resources and are often biodegradable, which can cause problems when bio-based materials are exposed to moisture and temperature conditions that are favourable for fungi. Fungal damage is not only an aesthetical issue, but can also severely compromise the structural integrity of a building component. Several standards exists for assessing the inherent resistance of wood species and the efficacy of wood preservatives, and are generally regarded to be sufficient and adequate. However, the existing standards are typically inadequate for the correct qualification of new wood products, whose durability is not enhanced with biocides but by new technologies, such as chemically modified wood (acetylation, furfurylation, etc.), thermally treated wood and also engineered wood products, such as glue-laminated wood, wood-based panels and wood treated with water repellents. In order to know whether the existing standard tests can be applied for bio-based materials other than (impregnated) wood species, certain material characteristics and their influence on fungal resistance as well as the standards’ test methodologies will need to be well understood. Therefore, it is key to unravel the influence of different material characteristics, like the material’s chemical components, its spatial structure and its moisture dynamics, all contributing to the material’s durability or resistance. In this paper, an experimental method is described in which the structure of a material is eliminated, so the chemical component of the material’s resistance can be separated from the other material characteristics. In se, the nutrient value of a material is tested for decay fungi, without the material’s structure and moisture dynamics playing a role.
L De Ligne, J Van den Bulcke, J Baetens, B De Baets, J Van Acker


Impact of temperature and relative humidity on spatio-temporal fungal growth dynamics of Basidiomycetes
2018 - IRG/WP 18-10905
Basidiomycetes can cause considerable damage to wood and other bio-based building materials. Knowing at which environmental conditions these decay fungi generally thrive, and how the environmental conditions affect fungal growth characteristics, is therefore of particular interest. In this paper, we use image analysis to assess the impact of the environmental conditions on the growth dynamics of Coniophora puteana. Fungal growth characteristics were tracked over time for sixteen different environmental conditions, obtained through a combination of four temperatures (15, 20, 25 and 30 °C) and four relative humidity (RH) conditions (65, 70, 75 and 80 % RH). Advanced time series analysis was applied to objectively compare the effect of the environmental conditions on these growth characteristics. In most cases, temperature and RH had a combined effect on fungal growth dynamics, yet an RH of 65% (independent of temperature) and a temperature of 30°C (independent of RH) resulted in a cease of growth after 10 hours. When defining optimal growth conditions for a fungus, it is therefore of primordial importance that the effect of temperature and RH is assessed simultaneously. The mycelial area and the number of tips were characterized by typical sigmoidal growth curves, whereas other characteristics such as the mean edge length remained constant over time. The method applied in this study allows for a quantitative and thus objective comparison of spatio-temporal fungal dynamics. Therefore, it can easily be employed for testing other factors influencing fungal growth, including different growth substrates.
L De Ligne, G Vidal-Diez de Ulzurrun, J Van den Bulcke, J M Baetens, B De Baets, J Van Acker


The restricted distribution of Serpula lacrymans in Australian buildings
1989 - IRG/WP 1382
Temperature data has been gathered over a number of years, not only for flooring regions of various buildings in Melbourne, but also within roof spaces and external to the buildings. Findings are discussed in relation to the distribution of Serpula lacrymans within Australia, its restriction to certain types of building construction and its restriction to flooring regions. The subfloor spaces of badly-ventilated, masonry buildings are highlighted as being better suited than are the subfloor spaces of, for example, Japanese buildings for the activity of this fungus. Hence Serpula lacrymans is very restricted in its distribution in Australia, yet where it is active it does grow rapidly and causes rapid flooring failures.
J D Thornton


On the Influence of Wood Destroying Fungi on the Feeding Intensity of Termites
2017 - IRG/WP 17-10893
The baiting and feeding stimulating effect of wood attacked by fungal isolates of the species Coniophora, Lentinus, Poria and Gloeophyllum on termites Reticulitermes santonensis is examined. There are significant relationships between the activity of fungal isolates and the feeding behaviour of termites. The most active isolates can be used for increase the attractiveness of wood to wood-destroying termites.
W Unger, T L Woods


Development on Damage Functions of Wood Decay for Building Envelope Design
2005 - IRG/WP 05-10556
For the hygrothermal analyses of building envelope systems for insulation design, we tried a natural decay test of wetted wood specimens without any inoculation of fungi. Three principal experimental types: under steady-state conditions (Experiment A), at a cyclic water dripping under Non-steady conditions (Experiment B) and at a cyclic water dipping under-steady conditions (Experiment C), were carried out for this purpose. After these tests, each specimen was determined its longitudinal compression strength. The detection of decay was checked this standard strength value by species according to Japanese building code and its corrected value by these moisture contents. As the results of the Experiment A, some fungal growth was observed within 10 weeks at the moisture contents of levels between 30wt% and 70wt%. As the results of the Experiment B, the simulated condition of short time condensation in summer was observed fungal growth but not affected decay problems within 124 weeks. As the results of the Experiment C, the simulated condition of periodical wetting as under floor or bottom of cladding was not observed any decay.
H Suzuki, Y Kitadani, K Suzuki, A Iwamae, H Nagai


The influence of gaseous oxygen concentration on fungal growth rates, biomass production and wood decay
1998 - IRG/WP 98-10283
The effects of air and several levels of oxygen balanced with nitrogen (% oxygen (v/v) nitrogen to 100%) on growth rates, biomass production and wood decay were investigated. The best technique for measuring daily growth rates in anaerobic jars was found to be by using 40 mm petri dishes which were attached to the walls of the jars. At the end of the test period the same petri dishes were also used for determining the dry weight of the fungal mycelia. The results showed that 5% oxygen concentration was very favourable for white rot and brown rot fungi (Basidiomycetes). When oxygen levels were reduced from 1% to 0.01%, the growth rates and dry weight of these fungi were steadily decreased. On the other hand, there was a large difference between very low oxygen levels (0.01 to 1%) and other levels (5 to 21% 02). In the case of other fungi there was not a big difference on their growth rates and biomass. Observational and numerical results on Fagus sylvatica (beech) and Pinus sylvestris (Scots pine) degradation by Coriolus versicolor, Coniophora puteana and Chaetomium globosum showed that there was a large difference in the degradation of the wood samples caused by C. puteana and C. versicolor when exposed to air and other levels of oxygen (0.25,1, 5 and 10% 02). Weight losses obtained by C. globosum as a soft rot on timber specimens in air and other oxygen levels were all in same range and below 5%. On the other hand there was a safety point at 5% 02 below which the fungus was unable to degrade beech. This point was 10% 02 for scots pine. At these points, weight losses were under 5%.
S M Kazemi, D J Dickinson, R J Murphy


Comparison of the effects of borate, germanate and tellurate on fungal growth and wood decay
1992 - IRG/WP 92-1533
The tetra-hydroxy borate ion is known to undergo complexation with polyols and has been shown to inhibit dehydrogenase enzymes in this way. It has been previously suggested that this complexation is responsible for the inhibition of fungal growth and the protection of boron treated timber. Other ions that have the ability to complex with polyols have also been shown to inhibit dehydrogenase activity. The effect of two of these ions on fungal growth and wood decay was compared to that of borate. It was found that both germanate and tellurate could reduce fungal growth and provide protection of wood against decay at similar molar concentrations as borate. The results have been used to further develop our understanding of the mechanisms of action of borate wood preservatives and substantiate the theory that borate ion/polyol complexation is responsible for the protection of boron treated timber.
J D Lloyd, D J Dickinson


Effect of cyclic change of temperature on fungal growth and mass loss
1994 - IRG/WP 94-10065
For estimating the effect of cycling change of temparature on fungal growth, four Japanese species, sugi (Cryptomeria japonica), hinoki (Chamaecyparis obtusa), akamatsu (Pinus densiflora) and buna (Fagus crenata), four fungal species, Tyromyces palustris, Gloeophyllum trabeum, Coriolus versicolor, Pycnoporus coccineus, and five temperature conditions, 10, 20, 27, 35°C and cyclic temperature (20°C 12 hours and 30 or 27°C 12 hours) under constant humidity (75% RH) were examined. The results were summarised that the cyclic condition was rather high fungal growth rate in the case of majority of fungi tested but was not surely increased the mass loss of wood. This tendency is rather clear in the case of brown rot like Tyromyces palustris. The cyclic temperature conditions were not favorable to the groth of Serpula lacrymans.
K Suzuki, K Okada


Resistance of acrylic paints on wood against growth of the rot fungus Dacrymyces stillatus
1990 - IRG/WP 2345
In the last few years the presence of the rot fungus Dacrymyces stillatus has been repeatedly confirmed in external wood panels, particularly from wood painted with water based paints. A laboratory method for testing of the fungal resistance of paint films on wood has been developed.This method has been used to test the efficacy of the fungicides Parmetol DF 18 and Parmetol HF 25 against attack by Dacrymyces stillatus. Recent findings regarding factors of importance for fungal attack of painted wood are also discussed.
J Bjurman


Evaluation of white-rot fungal growth on Southern Yellow pine wood chips pretreated with blue-stain fungi
2000 - IRG/WP 00-10349
White-rotting basidiomycetes do not colonize on southern yellow pine. This study seeks to reduce the resinous extractive content of southern yellow pine by treating it with blue stain fungi. The mycelial growth of wood-inhabiting ligninolytic white-rot fungi can be achieved on pretreated southern yellow pine wood. Aureobasidium, Ceratocystis, and Ophiostoma spp. removed 70% to 100% of the extractives from the southern yellow pine wood within a period of 3 to 6 days. Griofora fondosa, Hericium erinaceus, and Pleurotus ostreatus colonized readily after the treatment. As a result, ligninolytic white-rot fungi can be easily colonized on southern yellow pines pretreated with blue stain fungi.
S C Croan


A comparison of fungal strains used in the bioassay of wood preservatives
1984 - IRG/WP 2220
Previously published data are presented relating to a number of strains of wood-destroying basidiomycetes (Coniophora puteana, Coriolus versicolor, Gloeophyllum abietinum, Gloeophyllum sepiarium, Gloeophyllum trabeum, Lentinus lepideus, Poria placenta, Fibroporia vaillantii and Serpula lacrymans) commonly used as test fungi in the bioassay of wood preservatives. The data, which has not been statistically compared, consists of mycelial growth rates, decay capacities, and toxic values using agar, agar-block and soilblock methods based on data published over a period of almost 50-years. In many cases a large variation can be observed between strains originating from the same geographical region and between strains from different climatic-geographical zones. The differences between individual sub-cultures of the same strain, as used in various laboratories - or even in the same laboratories - are noted. Many of the published bioassay methods contain insufficient detail to make statistical assessments. Therefore, the authors have not attempted a definitive comparison of the numerous data. A proposal is presented to organize an international resource of pure cultural strains used as test organisms in bioassays of wood fungus may be dictated by local requirements.
J Wazny, H Greaves


Effect of amphiphilic antioxidant alkyl ammonium ascorbate on inhibition of fungal growth: Application to wood preservatives formulation
2008 - IRG/WP 08-30466
Amphiphilic surfactants were synthesized from ascorbic acid and different fatty amines and evaluated for formulation of wood preservation products. Characterization of physicochemical properties of the new compounds indicated classical behavior of cationic surfactants. Antioxidant properties, estimated using methyl linoleate oxidation inhibition method, were similar to that of ascorbic acid tested in the same conditions. Growth inhibition assays indicated that amphiphilic dodecylammonium ascorbate is able to inhibit Coriolus versicolor mycelium development, while butylammonium ascorbate deprived of surfactant properties has no effect. This compound was then investigated in the formulation of wood preservation mixtures containing propiconazole and compared to formulation obtained with an industrial surfactant. Biological tests based on the ability of these formulations to protect beech wood blocks exposed to a white rot fungus Coriolus versicolor were carried out under laboratory conditions. Results indicated that use of propiconazole formulation in aqueous solution allows to reduce the quantity of biocide compared to solutions of the same concentrations in ethanol. Protection achieved with antioxidant surfactant was slightly superior to that conferred by conventional surfactant.
C Gérardin , T Koumbi Mounanga, P Gérardin


Postia placenta gene expression of oxidative and carbohydrate metabolism related genes during growth in furfurylated wood
2009 - IRG/WP 09-10701
A range of studies the last decade have shown that modified wood can provide excellent protection against a range of wood deteriorating organisms, including decay fungi. However, we still lack information about why the modified wood is protected from microbial attack. Several hypotheses have been put forward e.g. inhibition of action of specific enzymes, but they still need testing. An understanding of the mechanisms utilized by decay fungi when exposed to modified wood is important for further optimisation of new modified wood products. In this study gene expression of the brown rot fungus Postia placenta has been monitored after 2, 4 and 8 weeks of colonization in furfurylated Scots pine and control samples. Preliminary results are given. The main finding was that genes related to oxidative metabolic activity was higher in furfurylated wood compared to untreated Scots pine, and that carbohydrate metabolism related expression was lower in furfurylated wood compared to untreated control.
G Alfredsen, C G Fossdal


Postia placenta gene expression during growth in furfurylated wood
2010 - IRG/WP 10-10734
Modified wood can provide protection against a range of wood deteriorating organisms. But we still lack information about why the modified wood is protected from microbial attack. Several hypotheses have been put forward for the mode of action against wood decaying fungi, including inhibition of action of specific enzymes, but they still need further testing. In this study gene expression of the brown rot fungus Postia placenta FPRL 280 has been monitored after 2, 4 and 8 weeks of colonization in furfurylated Scots pine (Pinus sylvestris L.) and in untreated control samples. Preliminary results are given. The main finding was that genes related to oxidative metabolic activity generally was higher in furfurylated wood compared to untreated Scots pine. Carbohydrate metabolism related expression varied. For one endo-glucanase and two β -glucosidases the expression was lower in furfurylated wood compared to untreated control, while for one glucoamylase and one glucan 1,3b glucosidase the expression was higher in furfurylated wood. The four cytochrome P450 tested, involved in breakdown of toxic compounds, gave inconsistent results between furfurylated and untreated control samples. Phenylalanine ammonia lyase and cytosolic oxaloacetase gave higher expression in control than in furfurylated samples.
G Alfredsen, C G Fossdal


Growth conditions for fungal decay in wooden constructions – practical experience versus literature
2011 - IRG/WP 11-10758
Data regarding moisture and temperature requirements of decay fungi found in literature have been compared to experience from observations in a large number of Norwegian buildings. A number of selected situations are discussed, among those exposure to high relative humidity, exposure to free water and decay in the supposedly adverse conditions on Svalbard. The moisture content in wood has to be at or above the fibre saturation point for lengthy periods of time for extensive decay to develop, which implies that capillary uptake of water must be involved. The relative humidity has to be close to 100 % for a long period of time in order for decay to develop at all. In assessment of risk of fungal decay it is crucial to consider the ecology of the built environment, involving temperature and time as well as the wood moisture content. The history of the construction part in question is more important than a single measurement of moisture content.
M Sand Sivertsen, J Mattsson


Studying fungal growth using automated image analysis and computer simulations
2016 - IRG/WP 16-20590
Wooden materials are prone to fungal attack resulting in damage and economic losses. Therefore many efforts have been made to understand the degradation of wood and to avoid the adverse effect of fungi. Even though the extent of degradation of a material is inversely proportional to the extension of the fungi attacking it, most researchers focus mainly on the former, leaving the study of the latter to mycologists. This results in a lack of practical methods to track fungal growth at realistic scales needed to study their growth characteristics in detail. Therefore, we have developed a new method based on image analysis and graph theory which is able to track the evolution of a fungal network over time. The only inputs needed are times series of images of fungal networks. This method is able to automatically compute the most important topological measures of fungal growth, as such enabling to track and compare the growth of different species under different conditions. In addition, this method provides information about the behaviour of hyphae, thus also enabling the calibration of mathematical models. As a way to avoid the drawback of experiments, we have developed a model for fungal growth whose main parameters can be obtained from the image analysis method mentioned above. The model is very versatile being able to represent fungal growth in both two and three dimensions and the interactions between the fungus and different materials. It is a lattice-free spatially explicit model: space is represented explicitly as such resulting in a more realistic representation of the fungi. Therefore, this model provides a powerful tool for the study of fungal growth, addressing the limitations of current modelling approaches and laboratory experiments.
G Vidal-Diez de Ulzurrun, J M Baetens, J Van den Bulcke, B De Baets


Fungal growth on coated wood exposed outdoors: influence of coating pigmentation, cardinal direction and inclination of wood surfaces
2017 - IRG/WP 17-10896
The objective of the SERVOWOOD project was to develop and establish European Standards that will facilitate the prediction of service life for exterior wood coatings. One of the objective of this project was to study fungal growth of the field exposed panels. Two coatings applied in 2 and 3 coats were exposed for one year outdoors at 45° south: one solventborne (alkyd based) and one waterborne (acrylic based) both in clear and pigmented versions. Fungal growth visually assessed was compared to fungal enumeration and the influence of exposure time on the main fungal species was studied. Results clearly showed that a lower fungal growth was observed on pigmented coatings. Despite the clear solventborne coating included a higher amount of biocide it was more susceptible to blue stain than the pigmented recipe. A new multifaceted exposure rig (MFER) designed for the project also contributed to the study of fungal growth. It allowed samples to be exposed with 9 different exposure directions and angles. The exposure using this MFER has shown that the worst cases (high area and high intensity of blue stain) were for samples with the clear coating exposed to north 45° and at the top of the MFER (horizontal surfaces). For any cardinal direction all surfaces inclined at 45° displayed more blue stain than vertical surfaces due to higher moisture content.
L Podgorski, C Reynaud, M Montibus


An experimental study of mould growth and wood decay in timber frame walls
2017 - IRG/WP 17-20623
This paper deals with parameters related to the occurrence of mould growth and wood decay in timber frame walls. In a first part, the hygrothermal conditions inside a timber frame wall finished with brick veneer cladding are analysed to get an idea of possible moisture related problems. It is shown that, based on the VTT mould prediction model, there is a mould risk on the interface between the insulation material and the wind barrier. As up to now no fully adequate methodology has been developed to predict service life of wood, the purpose of the present project is to obtain a thorough understanding of the onset and progress of fungal growth on wood and wood-based panels and the impact on the in-service performance of these building materials. Therefore, in a second part, the reader is introduced to the fungal control unit (FCU), designed and elaborated at Woodlab-UGent. Some very preliminary results are presented. In a first test stage, samples of Norway spruce, Scots pine and OSB were exposed to a constant climate of 25°C and 97% RH. After a period of 90 days, severe mould growth was observed on the Scots pine samples, whereas mould growth on the OSB sample was less prominent. The Norway spruce samples were visually not affected by mould growth, except for the area around knots. Furthermore, based on the resonalyser technique, a loss of stiffness is observed for all samples. This is however probably rather caused by the changes in moisture content and dimensions than due to fungal decay.
M Vanpachtenbeke, J Van den Bulcke, I De Windt, J Langmans, S Roels, J Van Acker


Hybrid green composites manufactured with glass fiber and jute fabric skin by VARTM process: Fungal, mold, and termite resistance tests
2017 - IRG/WP 17-40780
Hybrid green composites are increasingly used in building applications due to the development of new production approaches. Biological performance of such composites is needed when they are employed in extreme conditions. Hybrid composite panels were manufactured by wood furnish, glass fiber, and jute fabric skin by the vacuum assisted resin transfer molding (VARTM). Petri dish test method was followed to evaluate fungal resistance of produced composite specimens by employing Fomitopsis palustris, Trametes versicolor and Serpula lacyrmans. The specimens were also subjected to mold resistance tests. Test specimens were then bio-assayed against the termites in laboratory conditions. The specimens were highly resistant to fungi tested and termites; however, mold fungal growth was observed on the surfaces of the specimens with glass fiber at 10, 15, and 20% loading levels (without jute fabric) and the specimens with 5, 10, and 15% glass fiber and with jute fabric. Results suggest that the hybrid composite panels can be used as an alternative product to conventional commercial composites in severe degradation conditions.
S N Kartal, E Terzi, M Muin, A H Hassanin, T Hamuoda, A Kilic, Z Candan


Study on the ability of wood-destroying fungi to grow through chemically modified wood
2019 - IRG/WP 19-40858
Over the last decades, chemical wood modification technologies were developed to increase the resistance against attack by wood-destroying organisms without using biocides. Most of those technologies are based on an impregnation step initially. In most treated wood products, mainly by using solid wood in thicker dimensions as in posts, poles, sleepers, deckings etc. it is known that wood impregnation fluids are not distributed throughout the whole wood cross diameter, but just form a protected zone (‘shell-treatment’) of some millimetres or centimetres. The depth of the protected zone depends on wood species and treatment process. While ‘shell-treatments’ might be adequate to achieve a sufficient protection against fungal decay by treatment with biocides, the effect on how wood treated by chemical wood modification systems performs with regard to the resistance against wood-destroying organisms, is not yet known. On that basis, this study aimed at examining systematically the ability of wood-destroying fungi to grow through modified wood and degrade an untreated underlaying wood zone. Hence, decay tests were performed with pure cultures of T. versicolor (wr), C. puteana (br) and terrestrial microcosm (TMC) containing soft rot fungi and other soil-inhabiting micro-organisms. The incubation period of segmented specimens of 20 (ax.) x 20 x 45 mm³ (modified mantle, untreated core/dowel) was 16 weeks and tests conducted according to CEN/TS 15083-1 (2005) and CEN/TS 15083-2 (2005). By light microscopy photographs it was shown that both white rot and brown rot and also soft rot fungi can grow through chemically modified wood. The latter was shown independent of the modification agent which was acetic anhydride (acetylation) or 1.3-dimethylol-4.5-dihydroxyethyleneurea (DMDHEU), the treatment level and wood species of the modified mantle specimens. Significant mass losses (ML) of untreated wood (dowels), surrounded by a modified wood mantle, indicated that chemical wood modification does neither inhibit fungal growth nor affect the ability to degrade untreated wood substrate.
L Emmerich, S Strohbusch, C Brischke, S Bollmus, H Militz


Fungal damages in Norwegian massive timber elements – causes and measures
2019 - IRG/WP 19-40879
Massive wood elements are relatively new in Norway but the use is growing quickly, primarily the use of cross-laminated timber (CLT). Moisture performance of massive timber elements has been examined by some researchers, but more knowledge is needed. There is uncertainty regarding the need for vapour barriers or retarders in roof assemblies, and for practical reasons buildings are rarely assembled beneath construction tents despite awareness of the elements being moisture sensitive. Eleven cases regarding massive timber from the Mycoteam database have been studied. The cases were evenly distributed between the construction phase and the use phase. The types and causes of damage have been compared, and remedial measures studied where possible. Examination showed challenging in many cases, and long electrodes inserted into pre-drilled holes was often found the most feasible method for moisture measurements. The construction had to be opened to allow examination in five cases. Drying was observed to take from one week to more than five months, depending on extent and duration of wetting as well as drying conditions. The cause of moisture intrusion in all cases but one was insufficient protection from precipitation, either during the construction phase or due to construction errors such as faulty fittings or membranes. Fungal growth was observed in all but three cases, while decay was found in six cases. High moisture content within CLT elements did not cause fungal growth if the surfaces were kept dry. The major decaying agent in outdoor exposed CLT was Gloeophyllum sepiarium, whereas Antrodia sp. was most common in CLT not exposed to outdoor conditions. The authors expect the variation in decaying agents found in CLT not externally exposed to increase as the buildings age. More research is needed regarding risk of fungal damage in massive timber elements in combination with other materials.
M S Austigard, J Mattsson


Fungal colonisations in and on industrially manufactured acetylated glulam in UC 3
2020 - IRG/WP 20-40900
This poster paper describes one of the first cases where industrially acetylated glulam was colonized by wood-destroying fungi after less than 10 years of exposure in use class 3.2. Remarkable is that fruiting bodies of white as well as brown rot fungi were found on one and the same bench element. The first visible wood destroying fungi was the white rot fungus Schizophyllum commune followed by the brown rot fungi Gloeophyllum trabeum or Dacrymyces sp. Besides this, ascomycetes were found inside and algae on the surface of the modified glulam. It might be that this diversity of organisms enhanced the early attack. Even if the source of infection and its extent could not be sufficiently clarified, it can be assumed that the moisture and spore entry occurred mainly via the open adhesive joints or longitudinal cracks.
J Müller, E Melcher, T Potsch


Questionnaire - Fungal decay types
1985 - IRG/WP 1265
T Nilsson


The effect of certain wood extractives on the growth of marine micro-organisms
1977 - IRG/WP 438
S E J Furtado, E B G Jones, J D Bultman


Improvements of monitoring the effects of soil organisms on wood in fungal cellar tests
1996 - IRG/WP 96-20093
Accelerated testing the durability of preservative treated timber in a so called "fungal cellar" or "soil-bed" to evaluate its performance in ground contact is widespread practice. In order to obtain a more accurate and reproducible estimate of preservative performance, several institutes, among them the BAM in Berlin, have routinely carried out static bending tests in addition to visual examination. These tests were usually performed with a defined maximum load or deflection path regardless of the remaining degree of elasticity of the test specimens. Recent studies at the BAM revealed that by modifying the method, i.e. by restricting the applied load to the non-destructive interval for each individual test specimen, the calculated modulus of elasticity (MOE) reflect the changing strength properties caused by biological deterioration and allow within a relatively short time valuable predictions on the service life of the treated timber in soil contact.
I Stephan, S Göller, D Rudolph


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