Your search resulted in 439 documents. Displaying 25 entries per page.
Influence of a dipping preservative treatment on the performance of wood finished with waterborne coatings
1998 - IRG/WP 98-40121
Within a larger European research project on the performance of joinery finished with waterborne coatings, the influence of a water based dipping preservative treatment was studied in several ways. Six different waterborne coatings were tested with and without a preservative underneath the coating. The performance was tested on pine sapwood and spruce panels in a 2-year outdoor weathering trial on two different sites in Europe. The panels were evaluated visually with respect to cracking, flaking, surface mould growth and development of blue stain underneath the coating. In several cases the preservative treatment improved the performance of the coating, not only with respect to biological deterioration but also for cracking and flaking of the paint. A limited number of coatings were also tested on L-joints according to the EN-330 and of national dutch design. The EN-330 L-joints appeared to be a more challenging substrate compared to the national type, which had a glued connection between tenon and mortise. The influence of the preservative on the moisture content of the wood was evaluated by monthly weighing of the samples exposed outdoors and by laboratory measurements of the coating permeability. At least in laboratory trials the dipping treatment caused a slight reduction of the water permeability. This is most likely the result of the polymeric binder material present in the preservative. The presence of polymeric material underneath the coating was also confirmed in a microscopic evaluation of the distribution of the dipping preservative. The preservative was not equally distributed in the wood, but showed a clear preference for the ray-tissue.
M De Meijer, J Creemers, W Cobben, P Ahola
Enhancing the Performance of Transparent Coatings by UV Protective Pre-treatments
2006 - IRG/WP 06-30399
Most industry observers anticipate a change from copper-based preservatives to metal-free combinations of organics for residential treated wood products in North America within the next one to five years. While the chromium copper provide considerable protection against UV, metal-free formulations will need UV protection in the form of additives or coatings. While transparent coatings can be made reasonably resistant to UV, by necessity clear coatings are transparent to visible light. Visible light can also cause damage over the long term thus the underlying wood needs additional protection. Four novel UV protection systems were tested as pre-treatments on uncoated wood and under three coatings, a water-based film forming coating, a water-based acrylic varnish and a solvent based water repellent. Samples were exposed to natural weathering facing South at 45o at a test site in Saucier, Mississippi, in collaboration with the USDA Forest Products Laboratory. The test material was inspected every six months for discolouration, mold and stain, coating water repellency, flaking, erosion and cracking and substrate condition. After 24 months exposure, coatings over the combination of UV absorber and lignin stabilizer identified by Stephen Ayer and that recommended by Ciba and were both performing substantially better than controls with no pre-treatment. Projection of fitted curves beyond the data appears to indicate that pre-treatment may double the life expectancy of the coating. There was no consistent effect of the synergists on either combination at this time.
P I Morris, S McFarling
Relationship between coating properties and their performance on treated wooden decks
2008 - IRG/WP 08-30454
Preservative treated wood benefits from the application of a surface coating to protect it from weathering (UV and rain). Different preservative formulations may affect surface properties of treated wood differently; therefore compatibility of coatings with different preservative treated wood types should be considered. This paper examines coatings characteristics and their weathering performance when applied on different treated wood surfaces. The performance of a range of semi-transparent stains on chromated copper arsenate (CCA), alkaline copper quaternary (ACQ) and copper azole (CA) treated Southern pine wood was monitored over 18 months of natural weathering in Toronto, Canada. Additionally, the samples were tested under accelerated weathering conditions over a three month period. The ability of these coatings to reduce water uptake and leaching and general appearance of coated wood were measured, and the correlation with coatings properties such as: resin type, solvent base, surface tension, viscosity, density, solid content and pH was tested. The results showed that all coatings significantly reduced water absorption and preservative component leaching and higher viscosity stains had better performance in general. The coatings performed differently on different preservative treatments. Relative leaching performance was similar for accelerated and natural weathering exposure.
M Ahmadinejad, P A Cooper
Effect of CCA and Tanalith E on the performance of surface finishing
2008 - IRG/WP 08-40405
Effect of CCA and Tanalith E treatment on the performance of surface finishing properties was the objectives of this study. Sapwood of scots pine, (Pinus sylvestris L.) and oriental beech (Fagus orientalis Lipsk.) specimens (300 x 100 x 15 mm along the grain) were impregnated with aqueous solution of CCA 2% and Tanalith E 2%. Surface roughness, dry film thickness, adhesion strength, gloss measurement, scratch and abrasion resistance were determined according to related standards for treated and untreated samples. Results indicated that surface roughness and adhesion strength depend on wood species and the chemical composition of preservatives. Wood preservatives did not affect the scratch resistance because it depends on properties of the coating. Treatments with CCA and Tanalith E affected only the abrasion test for beech samples. The highest gloss value was determined on untreated (control) pine samples while there was no clear difference on gloss values between CCA and Tanalith E treatment.
T Ozdemir, A Temiz, I Aydin
Weathering of Wood Modified with the N-Methylol Compound 1,3‑dimethylol-4,5-dihydroxyethyleneurea (DMDHEU)
2009 - IRG/WP 09-40467
Scots pine (Pinus sylvestris L.) sapwood boards were treated with a methylated 1,3‑dimethylol-4,5-dihydroxyethyleneurea (mDMDHEU) causing weight gains of approx. 25% and exposed to weathering for 18 months. Compared to untreated boards, treatment with mDMDHEU reduced surface discoloration mainly caused by staining fungi. Boards treated with mDMDHEU exhibited clearly lower moisture content throughout the exposure time and lower water uptake in periodical submersion tests. The treatment also reduced deformation (cupping) and crack formation of the boards due to weathering (assessed as waviness and surface roughness). When coated boards were compared, prior treatment with mDMDHEU resulted in lower water uptake in periodical submersion tests, less discoloration, minor deformation (cupping) and less crack formation (assessed as waviness and surface roughness). Oil-based coatings did not peel off the mDMDHEU treated board surfaces as observed for the untreated board surfaces. Scots pine veneers were modified with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) to weight percent gains (WPG) of 10, 27 or 48% and exposed to artificial weathering. Initially, weight losses of unmodified veneers were significantly greater than those of DMDHEU treated specimens. The weight losses of all treated veneers during 144 h of weathering, however, were similar to those of the unmodified controls. Scanning electron microscopy revealed that DMDHEU treatment was highly effective at preventing the degradation of the wood cell wall during weathering. Tracheids in unmodified veneers became distorted within 48 h of weathering exposure, whereas cells in modified veneers, especially those reacted to higher weight percent gains, retained their shape even after 144 h weathering.
C Mai, Yanjun Xie, A Krause, K Urban, P D Evans, K Richter, H Militz
Impact of wood species on the performance of exterior wood coatings
2010 - IRG/WP 10-40519
To prolong the service life of a wooden construction the protective function of a coating is of utmost importance. The chemical composition as well as the wood-coating interface affects the performance of this protective layer and obviously wood species have an impact too. This paper discusses the influence of wood species on the overall coating performance. Therefore, a range of opaque waterborne acrylic coatings applied on industrially finished window frames made of frequently used commercial hardwood and softwood species were tested. Both, artificial and natural weathering, were considered for the durability assessment. Complementary studies on moisture dynamics and fungal growth were included as well. Coatings applied on dense tropical hardwood with large vessels perform fairly well in regard to water related failure, but erosion or weathering phenomena occur early. The opposite is true when examining small or medium porous hardwoods. Coatings applied on softwood substrates performed the worst. Yet, in contrast to hardwood, the performance of softwood based systems under laboratory test conditions is less correlated with outdoor performance.
I De Windt, J Van den Bulcke, J Van Acker
Silicon compounds as additives improving alkyd-based wood coatings performance
2010 - IRG/WP 10-40531
The reactivity of cellulose with solvent-born alkyd-based wood coatings supplemented with organosilanes was analyzed. Structural analysis of cellulose subjected to the reaction with organosilanes and following extraction with water was performed using Fourier-transform infrared spectroscopy (FTIR). The analyzed IR spectra comprise bands 1250 cm-1 typical for the SiC group and 800 cm-1 typical for vibrations of SiC and/or SiO groups. The presence of these bands in the spectra proves the occurrence of a reaction between cellulose and organosilanes. Silicon concentration in cellulose was determined by AAS after the reaction with coating system after leaching.
B Mazela, I Ratajczak, K Wichłacz-Szentner, P Hochmańska
Moisture protection and performance during 5 years exposure of 19 wood coating systems on a cladding in Vienna
2011 - IRG/WP 11-40561
A cladding with vertical boards of Norway spruce (Picea abies) comprising different coating systems had been exposed to natural weathering oriented south west in Vienna for 5 years. Weathering behaviour of the boards was assessed in intervals and wood moisture content was measured over the first 22 months of exposure. The moisture protective properties of the coating systems were assessed using laboratory methods. The results of weathering behaviour indicated higher coating durability with higher dry film thickness and lower transparency of the coating systems. The coating systems provided a certain degree of moisture protection that was influenced by paint colour, water permeability and surface roughness. Panels with low permeable coatings showed a better performance in natural weathering.
G Grüll, I Spitaler, M Truskaller
Comparison of exterior performance of two coating systems based polyurethane applied Pinus sylvestris L. and Picea orientalis L. wood
2012 - IRG/WP 12-40588
Some surface changes in sapwood and heartwood of two species before applying clear-coating were characterized after accelerated weathering time. Wood specimens covered with two types polyurethane (PU) films were also observed in accelerated weathering exposure. In this study, changes on the wood surface were compared of between wood specimens covered with two types polyurethane (PU) films after irradiation. The study was carried out on sapwoods and heartwoods two wood species; Fagus sylvatica L., Pinus sylvestris L. The artificial weathering experiment was performed by cycles of 2 hours UV-light irradiation followed by water spray for 18 minutes according to ASTM G 53-96. The surface changes of the weathered sapwood and heartwood samples applied clear-coating were characterized by surface roughness and color measurements. Color measurements were made by a with a Konica Minolta CM-600d (Canada) at several intervals (0-24-72-168-240-336-408-504-600-672 hours) in artificial weathering of treated and untreated wood. Additionally surface roughness was measured on the surface of all wood samples, unweathered and after 672 hours of weathering by a Mitutoyo Surfest SJ-301 instrument. According to the results, the scots pine and spruce sapwood samples provided better protection color changes than the scots pine and spruce heartwood samples showed lower color changes. The highest increasing surface roughness values were on the wood samples applied 2.system clear-coating (Y) by reason of the wood surfaces contain several checks, splits and cracks caused by weathering. The wood surface applied 1.system clear-coating (X) showed that no high cracks and substantially surface properties changes were observed significantly due to weathering.
Ö Özgenç, Û Cafer Yıldız
Effect of polyurea coatings on performance of Douglas-fir in tropical above ground exposures
2014 - IRG/WP 14-40665
The potential for using polyurea barriers to limit fungal and termite attack was investigated on Douglas-fir lumber and timbers. Termites were capable of penetrating the barrier to attack non-treated wood as well as wood dip-treated with disodium octaborate. The coatings were also exposed above ground for 48 months in Hilo Hawaii. Samples were dissected to detect internal decay. Coated non-treated timbers had decay on the upper and lower edges of the coatings, but no decay fungi were isolated from the wood. Examination of the coatings showed that the upper, surfaces exposed to ultraviolet light experienced surface erosion and loss in maximum tensile load. The results indicate that the barriers cannot completely protect wood against fungal or termite attack, but have merit for providing supplemental protection to treated wood.
S Uysal, J J Morrell
Indentation and pendulum hardness tests: two convenient assessment methods of the performance of exterior wood coatings
2015 - IRG/WP 15-40689
Developing formulations of exterior wood coatings with long service life is a big challenge. For many years in Europe the performances have been mainly evaluated through weathering tests (within the EN 927 series) followed by visual assessment (blistering, flaking, mould growth, chalking and cracking), colour and gloss measurements, and adhesion tests. Very recently the importance of the mechanical properties of coatings has been taken into consideration within the CEN/TC 139/WG2 and a test method (CEN/TS 16360) has been suggested to assess the film extensibility by indentation of a coating on a wooden substrate. In 2014 this technical specification was added in the EN 927-2 standard. The aim of this work was to investigate this destructive indentation test for several commercial acrylic coatings applied on spruce and Scots pine. In addition, pendulum hardness tests were carried out as a non-destructive test to gain further information about mechanical properties of the tested coatings. The influence of thickness was examined. This work discusses the advantages and the limits of both methods. They allowed a discrimination of the coatings studied and gave a similar ranking for most of the coatings. The paper also shows the relationship between pendulum hardness variation and long-term performances. Indentation and pendulum hardness tests are shown as useful investigations in addition of the conventional assessment framework of exterior wood coatings.
L Malassenet, L Podgorski, M Truskaller, G Grüll
Investigation of Dimensional Stability and Coating Performance of Different Heat-Treated Poplar Wood Before and After Accelerated Aging
2015 - IRG/WP 15-40702
In this investigation, coating performance of heat-treated poplar wood (Populus tremuloioes) in different environments, before and after accelerated aging was studied. Specimens with 150×100×20 mm and 20×20×20 mm in dimensions were prepared. Heat treatments were performed in air, steam and linseed oil media. Specimens were coated by alkyd based stain. Adhesion strength before and after aging, long term water absorption and volumetric swelling were studied and analyzed statistically. The results showed that heat treatment increases the adhesion strength (especially in air and steam). By increasing the temperature, all specimens showed increases in adhesion strength, except adhesion strength before aging in oil-heat treated specimens. OHT increased adhesion strength of coating after accelerated aging. Heat treatment reduced the rate of water absorption and thereby improved the dimensional stability of the samples.
A Talaei, D Ansari Movahed, G Rassam
Accelerated Weathering Performance of Impregnated Wood Samples Coated with Zinc by Means of Plasma-Assisted Particle Deposition
2016 - IRG/WP 16-30682
Many different methods are currently applied for wood protection against outdoor conditions. The most important of these is the process of impregnation with liquid substances. However, this kind of wood preservatives cannot provide a long-term protection of wooden surfaces. Weathering-resistant surfaces can be obtained by applying UV absorbing agents. In this study, the influence of zinc particles applied by a plasma process at atmospheric pressure against UV light was investigated. First, wood samples were impregnated with boric acid, tall oil or copper azole. After impregnation, the samples were coated with zinc (Zn) particles, and coated and uncoated samples were exposed to accelerated weathering tests. The changes of the surface properties of the treated and untreated wood samples were studied by color changes, glossiness. Physical properties such as color changes, glossiness and surface roughness decreased for the samples coated with Zn particles. Brightness values also increased with the increasing weathering period.
A Can, H Sivrikaya
Development of methodologies to evaluate tanning blocking coatings
2016 - IRG/WP 16-40760
In Europe an increased interest in using home-grown hardwoods as sustainable and renewable construction materials started a few years ago. Amongst these species oak and chestnut are two interesting candidates as their heartwood contain a significant amount of tannins which contribute to their natural durability. To avoid wood greying and dimensional variations, oak and chestnut must be protected by coatings. The European VOC Directive has been the driving force behind the change from solvent borne to waterborne coatings. Therefore bleeding of water- soluble tannins can be observed during the coating application. This phenomenon may also occur during service life due to humidity and rainfall, leading to some ungraceful aesthetic aspect for the construction. Manufacturers have therefore developed specific coatings to control tannin-staining. Moreover due to the specific anatomy of oak and chestnut (large vessels), coatings need also to be flexible enough to cover the irregular surface of these woods. In Europe a standardized test method to assess the performance of these coatings is not yet available. Each manufacturer has developed anti-bleeding coatings using its own tests. It is then difficult to compare objectively the performance of the different products available on the market and to advise the manufacturers for possible improvement of their coatings. This paper describes the advantages and drawbacks of some methods used to qualify different coatings available on the market. Permeability to liquid water and immersion tests are suitable and easy methods to provide evidence of the performance of anti-tanning staining coatings. These methods give information regarding the barrier properties to tannin bleeding and the capability of the coating not to be discoloured.
C Reynaud, L Podgorski
Studying Weathering Performance of Coatings on Thermally Modified Wood
2017 - IRG/WP 17-40805
Thermal modification and degree of improved properties depends on wood species and treatment parameters. Southern pine and spruce are the two common wood species for decking, fences and siding in North America. This study was the first to evaluate coating performance when applied on oil-heat-treated southern pine and spruce wood samples. Water uptake, colour and gloss changes of samples were analysed before and then every month for the first three months and then every six-months during 18 months of natural weathering in Toronto, Canada. The results showed the coated heat-treated woods had lower water uptake, lower colour change and overall better appearance ranking than coated-untreated wood samples. Spruce samples that were used in the study had lower checking and splitting and in general superior performance compared to southern pine treated samples. Notably, the average moisture content of treated spruce wood samples were significantly lower than southern pine, which explains lower checking and better coatings’ appearance.
M Nejad, M Dadbin, P Cooper
In-service performance of wood claddings and windows – a Norwegian survey
2018 - IRG/WP 18-20632
The overall aim of the study was to strengthen the empirical data on decay frequency and in-service performance of claddings and windows in Norway. Data from a survey of claddings and windows from 38 Norwegian houses is presented. The main findings for wooden claddings: 1) predominance of decay was detected in east facing claddings, while the largest decayed areas were located on south facing claddings, 2) yellow and grey were the most used cladding coating colours and these houses also had most cases of decay damage. Yellow coloured cladding had significantly larger mean decayed areas than grey coloured cladding. The main findings for wooden windows: 1) predominance of decay was found on south facing windows. South facing windows also had significantly larger decay damage areas than east and north facing windows, 2) white and grey were the most frequently used window coating colours. Grey windows had significantly larger mean decay damage areas than white windows. Given the right execution of details and maintenance regime wooden claddings and windows can last for more than 50 years in Norway.
L Ross Gobakken, G Alfredsen
Influence of weathering on the mechanical properties and performance of exterior wood coatings
2022 - IRG/WP 22-40951
Three commercial coatings were exposed to artificial (EN 927-6) and natural weathering (EN 927-3) on wood samples. Cracking was visually assessed as well as Persoz hardness. Free films of the same coatings were also exposed to the same weathering tests before their tensile properties were measured. Results show that artificial and natural weathering modified the overall mechanical properties of wood coatings. The elastic modulus and the strength increased whereas the strain at break dramatically decreased from the first hours of exposure. For selecting good performing coatings, our results show that it is useful to consider the variations of the elastic modulus and to calculate the retention of the initial strain at break after weathering instead of considering the strain at break result. A significant increase in the elastic modulus lead to cracking. Coatings performed better when their modulus remained below 400 MPa and their retention in strain at break was higher than 20%. The study shows that short artificial ageing tests (< 500 h) on free films are relevant to highlight changes in strain at break observed in natural weathering. They are therefore a valuable tool in the formulation of high-performance products. The mechanical properties measured using the Persoz hardness test are also interesting to take into consideration in order to anticipate the risk of cracking. For the three coatings, the Persoz hardness increased more or less due to weathering. The results show that coatings with an initial Persoz hardness higher than 80 seconds should not be chosen for wood exposed outdoors because their risk of cracking is higher.
L Podgorski, J-D Lanvin
Management of the wood and additives wastes in the wood processing industries: Problematics and technical answers review
1996 - IRG/WP 96-50073
Management pathways for pure wood subproducts are well known and used; but as soon as additives like preservatives, glues, varnishes or coatings are present within the wood wastes, their disposal or valorization becomes more tricky. The different kinds of mixed wood wastes of the wood processing industries, from the sawmill to the furniture manufacture, are identified herewith and their diversity is examined. These wastes can be classified according to their danger characteristics, taking into account the type of additives, their concentration, their availability for the environment, the physical state of the waste. Different disposal pathways are then considered. Combustion, with the possibility of energetic valorization seems the best answer for a major part of these wastes. But this is only possible if good combustion conditions are defined, so that no harmful products are emitted. Moreover, these conditions must be affordable on the technical and economical point of view. Then, some wastes cannot be burned in such a simple way, and need a larger approach, which is presented in this document.
S Mouras, G Labat, G Deroubaix
Proposed method for out-of-ground contact trials of exterior joinery protection systems
1981 - IRG/WP 2157
Methods for testing the efficacy of preservative treatments for exterior joinery are described using the format of a European Standard. Commercially used treatments applied to jointed test units (L-joints) which are then protected by conventional finishes are exposed to normal outdoor hazards out of ground contact. Assessment is made a) by determining eventual failure through decay and b) by destructive examination of replicate treated and untreated units, after increasing time intervals, rating comparative performance in terms of wood permeability increase and the progress of microbial colonisation.
J K Carey, D F Purslow, J G Savory
JWPA method for testing effectiveness of surface coatings with preservatives against decay fungi
1981 - IRG/WP 2164
In 1979 JWPA established a new method for testing effectiveness of surface coatings in accordance with practical use of preservative-treated lumber. Comparing the new testing method with JIS A 9302, a few new trials - size of wood specimen, weathering procedure, and decay-test procedure - are incorporated.
Field performance of wood preservative systems in secondary timber species
1997 - IRG/WP 97-30152
The objective of this ongoing study is to evaluate the performance of new, potential, and standard wood preservative systems in secondary North American timber species. Eleven preservative systems were evaluated in this study - ACQ Type B, Copper Citrate 2: l, CDDC, chlorothalonil/chlorpyrifos, copper-8-quinolinolate, tebuconazole/chlorpyrifos, RH287, propiconazole/chlorpyrifos, copper naphthenate, CCA. and creosote. Field evaluations are being performed with ground contact field stakes and termite-specific testing in Hawaii, along with laboratory soil bed tests. The major wood species used with all the systems and evaluation methodologies are loblolly pine, northern red oak, tulip poplar, and cottonwood. More limited evaluations (field stakes only) are being conducted with eastern hemlock, red maple, and sweetgum. Information is presented from laboratory soil bed, field termite, and field stake evaluations. There is good correspondence between soil bed and field stake results. The more highly developed preservative systems and those in an AWPA P9 Type A oil carrier tend to perform better, and there can be a strong affect on performance from the wood species.
P E Laks, K W Gutting, R C De Groot
How to Document the Performance of Super-Critical Treated Wood in above Ground Situations?
2005 - IRG/WP 05-20316
The paper presents practical experiences from the preparation of a new preservative treated wood product for introduction to the market. The product in question is Superwood™, which is treated with organic biocides using CO2 in a supercritical state as a solvent. The question is how to evaluate the performance of a new product such as Superwood™ in order to get an acceptance on the market and fulfil the formal requirements. In the European Union countries, the EN 599-1 is the standard that needs to be complied when approving a new product for the market, but it only focuses on the toxic limit against representative decay fungi according to EN 113. However, decay test, above ground and other forms of field tests are optional, this is not in line with the traditional test philosophy in the Scandinavian countries. The open question is to which extent treatment to the level of the toxic threshold value also ensures a long service life and expected performance of the treated commodity. Superwood™ is evaluated using a strategy, in which basic laboratory tests are done to get the toxic value (according to EN 599-1) and in addition a number of field tests are done including accelerated testing in the tropics. These tests are focussed on the evaluation of the performance criteria such as durability and service life and maintenance requirements. These questions must be answered by the producer without having a full record of performance test for their new products. A short status on the test performed on super-critical treated wood (Superwood™) is presented. Based on a comparison between field test in Scandinavia and in the tropical Malaysia a service life of more than 25 years for a specific supercritical treated product is estimated. It is stated that the existing European standardisation system is insufficient when it comes to service life prediction. A number of important questions need to be addressed by the European standardisation system as soon as possible because the market and the public opinion change quickly due to environmental concern.
N Morsing, A H H Wong, F Imsgard, O Henriksen
Summary of development of pile wrappings in Los Angeles Harbour
1987 - IRG/WP 4141
Performance of treated fence posts after 6 years in five test plots in the State of Sao Paulo - Brazil
1976 - IRG/WP 376
Fence posts treated with creosote, pentachlorophenol and creosote/ pentachlorophenol mixtures showed good performance after 6 years of exposure in five test plots located in the State of Sao Paulo - Brazil. Good results were also achieved with copper sulphate/sodium arsenate and copper sulphate/potassium dichromate mixtures. Fungi and termites were the main destroying agents found attacking the posts.
M S Cavalcante
Comparison of Different Methods for Assessing the Performance of Preservatives in the BAM Fungus Cellar Test
1998 - IRG/WP 98-20149
The fungus cellar test is a common means to get reliable data on the long term performance of treated wood in soil contact. A constantly high humidity and a suitable of water holding capacity for a range of micro-organisms provide high decay rates in untreated wood and produce intensive microbial pressures on wood treated with biocides. Presently a range of biocides are under test in the BAM fungus cellar and the results will be presented for the following types of biocides: Tebuconazole in combination with copper and boron (5 years fungus cellar), quats with copper and boron (5 years fungus cellar) and Cu-organic compound combined with copper and boron (3 years fungus cellar). Figures will be shown on the development of the Modulus of Elasticity (MOE) over the years and on an assessment of the stakes according to EN 252.
I Stephan, M Grinda, D Rudolph