Your search resulted in 340 documents. Displaying 25 entries per page.
Mould growth on spruce claddings and the effect of selected influencing factors after 4 years of outdoor testing
2015 - IRG/WP 15-30671
Norway spruce (Picea abies) is the most frequently chosen wood species as claddings in façades in Norway, and is used both coated and uncoated. The visual changes that occur during weathering can be colour changes, abrasion or wear, blistering, flaking, and even cracks in the wood or coating, but more often growth of mould and blue stain fungi is the main challenge. A field test with synchronous monitoring of relative humidity, air temperature, material temperature and wood moisture content in Norway spruce claddings has been performed in southern Norway as part of the ClimateLife project. Visual evaluation of blue stain and mould growth according to EN 927-3 was performed, and evaluation data after 46 months exposure is presented. The objectives were to study the effect of 1) environment, 2) cardinal direction and 3) colour of the coated surface on growth of blue stain and mould fungi and to study the variation in relative humidity, air temperature, wood moisture content and material temperature. After 46 months exposure, the red coating system had generally the lowest mould ratings and the uncoated claddings had the highest. Of the white coloured claddings the ones facing south had lower mould ratings than those facing north, but the opposite were found for red coloured claddings. The relative humidity was higher in front of claddings exposed northwards and in a shaded environment compared to an open environment against south. In an open environment red coloured claddings had the lowest wood moisture content and highest material temperature, and red coloured claddings against south had the highest maximum material temperature.
L Ross Gobakken, G I Vestøl
High-frequency monitoring of mass loss due to brown rot degradation of modified wood
2016 - IRG/WP 16-10862
Fungi growing in liquid culture undergoes three separate phases in which they i) adapt to the new environment, ii) grow unrestrictedly and exponentially, and iii) are inhibited to increase in number/mass due to lack of nutrients etc. Filamentous fungi have been shown to exhibit similar growth phases in a solid food substrate and have been modelled to grow in this way also in solid wood. In modifie...
R Ringman, A Pilgård, K Richter
On the effect of climate and exposure conditions on durability indicators and their potential for service life prediction of wood-based products
2016 - IRG/WP 16-20576
In order to encourage increased use of wood, different user groups need to be better informed regarding the variation in performance between different wood materials and the effect of different use classes. It is also important to provide good empirical data on the service life of wood products as input to for example life cycle assessment studies. In the current study the effect of temperature an...
G Alfredsen, C Brischke, P-O Flæte, M Humar, L Meyer-Veltrup
Variation in moisture content in field trials according to use class 3.2 conditions
2016 - IRG/WP 16-20580
Different test methods to determine the durability of wood in use class 3 (EN 335:2013) are available. Fungal degradation of wood requires liquid water. Different Standards (EN 335-1:2006; DIN 68 800:2011) specify the risk for decay with moisture content (mc) of above 20%. EN 335 (2013) does not specify moisture content but rather defined limited wetting conditions (use class 3.1) or prolonged wet...
S Bollmus, A Gellerich, H Militz
Measurement of Cell Wall Moisture in Acetylated Radiata Pine Using Low-Field Nuclear Magnetic Resonance
2016 - IRG/WP 16-20583
Understanding the interaction of water with acetylated wood is necessary to explain how the protective mechanism of acetylation functions. Low-field nuclear magnetic resonance is one technique for assessing water in wood. Pinus radiata earlywood sapwood samples were acetylated to various weight percentage gains and then analysed with this method. Increased levels of acetylation showed significantl...
H G Beck, C A S Hill
Wood biodeterioration monitoring using molecular fluorescence
2016 - IRG/WP 16-20589
Wood is an extremely complex and heterogeneous biological material, susceptible to biodeterioration by wood-destroying organisms. This process can be evaluated by natural resistance tests or non-destructive techniques, such as molecular fluorescence. The fluorescence of wood can be attributed to the presence of fluorophores groups or extractives, as a characteristic of some species. This study aim...
E Meneses Oliveira, A Florian da Costa, J W Batista Brag
Insight in moisture dynamics of wood treated with organosilicon compounds
2016 - IRG/WP 16-20598
The SILEX project “Improving sustainability of construction materials using innovative Silicon based treatment” is a Life+ project with reference LIFE+11 ENV/BE/1046 and started in April 2013. This project intends to demonstrate that a new class of compounds can be used for wood treatment for an extended service life combined with enhanced new testing methodology. The project aims at demonstra...
J Van Acker, J Van den Bulcke, I De Windt, S Colpaert, S De Rocker, S Salvati, J-P Lecomte
The durability of manufactured structural building materials
2016 - IRG/WP 16-40718
The projected market potential for Engineered Wood Products such as CLT (cross laminated timber) is very positive however, potential prolonged rain leakage or moisture exposure during construction and in-service could pose considerable concern for its durability and reputation. This research was conducted to assess the decay resistance of CLT and OSB (oriented strand board) in an accelerated trial...
T Singh, D Page
Superhydrophobic treatment of Norway spruce wood for improvement of its resistance against brown rot and moulds
2016 - IRG/WP 16-40734
Water repellence of wood can be increased and its some other properties influenced by introduction of hydrophobic chemicals into and on cell walls without affecting the wood’s bulk density due to lumen filling. Herein, a simple dipping method to insert octadecyltrichlorosilane (OTS) into cell walls and to deposit the self-assembled hydrophobic monolayers (SAMs) of OTS is reported. It was found o...
A Kumar, P Ryparová, P Hajek, B Kričej, M Pavlič, A S Škapin, M Šernek, J Tywoniak, J Žigon, M Petrič
Role of cell wall specific moisture content on the brown-rot fungal attack on wood
2016 - IRG/WP 16-40736
Wood is a hydroscopic resource because the cell wall polymers contain hydroxyl and other oxygen-containing groups that attract moisture through hydrogen bonding. Moisture content varies with changing moisture content in its environment. The moisture content in wood is responsible for many of the performance properties we observe. The strength properties of wood are dependent on the moisture con...
R M Rowell
Encapsulation of poles to prevent moisture uptake – a laboratory test
2016 - IRG/WP 16-40753
Premature failure of utility poles due to decay in soil contact is the main reason for early removal of utility poles, a measure that implies extra costs for utilities. Remedial treatments and barriers are common methods to prolong the service life of utility poles. The first part of this paper gives an overview of mode of action and commercial application of barrier systems as described in the li...
K-C Mahnert, U Hundhausen
Case study: “Riesenbühlturm”
2017 - IRG/WP 17-20599
In this case study four 7 m long Douglas fir crossbeams were investigated regarding the remaining metal and moisture content. The crossbeams were replaced from a timber tower after 10 years of service in the Black Forest region (South Germany) due to fungal decay. From each of the crossbeams five stem discs were taken and relevant parameters (density, moisture and remaining metal content) were de...
E Melcher, J Müller
The sorption behaviour of wood
2017 - IRG/WP 17-20605
The use of dynamic vapour sorption to determine the sorption properties of wood has become an increasingly popular technique. The method has many advantages when compared with many other gravimetric methods. However, it is necessary to set an equilibrium condition in order to obtain data for an isotherm in a reasonable amount of time. An important recent finding has been that multiple sorption cyc...
C Hill
Monitoring of wood biodeterioration by infrared spectroscopy
2017 - IRG/WP 17-20607
The susceptibility of wood to deterioration by rotting fungi is intrinsically related to its chemical composition and the environmental conditions at its place of use, and if not detected in time, can cause enormous financial losses. The process of wood biodeterioration by decay fungi can be evaluated through laboratory accelerated test, in specific field tests, or through non-destructive techniqu...
E Meneses Oliveira, A Florian da Costa, J W Batista Braga
Modelling of moisture content in timber bridge details
2017 - IRG/WP 17-20613
The design of details is an important aspect in durability design of timber bridges. Details are often considered the weakest points in bridges due to their tendency to trap and accumulate moisture and thus facilitate decay. When designing maintenance plans and inspection intervals, it is important to know how design choices will come to influence the service life. Moreover, service life and wood ...
J Niklewski, C Brischke, E Frühwald Hansson, L Meyer-Veltrup
Monitoring Diversity and Colonization Patterns of Wood-Inhabiting Fungi Using Field Stake Tests
2017 - IRG/WP 17-20614
Advances in molecular identification of microbial communities enabling rapid microorganism determination have allowed ecological data to be increasingly incorporated into standardized wood performance tests. Combining standard field tests with molecular methods to study wood-associated microflora can help to better understand fungal colonization and decay processes of wood in service. The potentia...
P Torres-Andrade, J Cappellazzi, J J Morrell
Influence of Weathering on Moisture Performance of Wood
2017 - IRG/WP 17-20619
Water performance of wood is besides the inherent durability the most important factor that influences on the performance of wood in outdoor, above ground applications. Therefore it is of significant importance to optimize the methods that are able to predict the moisture behaviour of wood in outdoor applications. In order to elucidate this questions, samples were prepared of oak (Quercus), sweet ...
M Žlahtič-Zupanc, B Lesar, N Thaler, M Humar
COST FP 1303 Cooperative Performance Test – Results after two years outdoor exposure
2017 - IRG/WP 17-20620
COST Action FP 1303 ‘Performance of Bio-Based Building Materials’ started in October 2013 and an ambitious program was set up for four years. Among this a collaborative field test was planned. The idea of the cooperative performance test was to distribute a fairly simple test set up to as many places in Europe as possible in order to collect performance data reflecting the full range of climat...
B Lesar, M Humar, C Brischke, L Meyer-Veltrup, D Jones, N Thaler, J M Abascal, G Alfredsen, B Brunnhuber, E Grodås, M Irle, J Kers, M Klamer, K-C Mahnert, E Melcher, S Palanti, M Noël, E Suttie, N Pfabigan, M Touza
Moisture performance of wood determined in laboratory and field trials
2017 - IRG/WP 17-20621
It is widely accepted that wood moisture content (MC) is the key factor when it comes to durability of wooden structures exposed to weathering. The moisture performance of wood and wood-based products has been recognized as key element in wood durability and wood protection. Actually, it should be considered as major component of the material-intrinsic resistance of wood, but never found its way i...
D Kržišnik, N Thaler, B Lesar, M Humar
Moisture content as a quality control parameter in thermally modified timber production
2017 - IRG/WP 17-20622
Quality assurance (QA) or factory production control (FPC) is necessary to ensure a proper production process. The requirements of QA/FPC can result from EN and national standards, quality assurance systems, or producer-specific rules.
TMT producers must ensure that the process was correct, and to ensure traceability of products. In addition to the electronic records, the material should be che...
W Scheiding, H Turkulin, S Stein
The use of new, aqueous chemical wood modifications to improve the durability of wood-plastic composites
2017 - IRG/WP 17-40787
The wood flour used in wood-plastic composites (WPCs) can biologically deteriorate and thus the overall mechanical performance of WPCs decrease when exposed to moisture and fungal decay. Protecting the wood flour by chemical modification can improve the durability of the wood in a nontoxic way so it is not harmful to the environment. WPCs were made with modified wood flour and then evaluated for m...
R E Ibach, C M Clemons, G C Chen
Solid Timber Bridges – Latest Developments
2017 - IRG/WP 17-40788
The technology of gluing in wood construction has evolved considerably in recent years. This has been shown especially in timber bridges that Glulam is now the main building material. A further development is the so-called block gluing, which provides a good basis for supporting structures. Numerous bridges, especially in central Europe, appeal by unique design and monolithic and solid construction. These structures base on two main developments: block lamination of glulam and the composite of timber and concrete to one structural system.
F Miebach
Moisture behaviour and biological durability of high performance flax fibre reinforced composites
2017 - IRG/WP 17-40803
For natural fibre composites in structural and load bearing applications long reinforcing fibres are required. Therefore, much research is performed on flax fibre reinforced composites to optimize them for high performance use. In most cases such research focuses on the mechanical properties, yet the assessment of moisture behaviour, dimensional stability and biological durability is an important ...
N Defoirdt, J Van den Bulcke, F Bensadoun, J Ivens, I Verpoest, J Van Acker
Organosilicon-based impregnation hydrophobers for wood
2017 - IRG/WP 17-40808
The SILEX project “Improving sustainability of construction materials using innovative Silicon based treatment” is a Life+ project with reference LIFE+11 ENV/BE/1046 and started in April 2013. This project intends to demonstrate that a new class of compounds can be used for wood treatment for an extended service life combined with enhanced new testing methodology. The project aims at demonstra...
J-P Lecomte, J Van Acker, J Van den Bulcke, M Kutnik, M Montibus, S Salvati, S Derocker
Review on protection of timber bridges in Norway and other countries
2017 - IRG/WP 17-40809
Wood plays a major role in design and construction of modern bridges in Norway. Typical elements of those bridges are double impregnated glued laminated members, stress laminated timber decks, slotted-in steel plates, metal cladding of the surfaces of loadbearing members, and cross girders made of steel. Selected examples of timber bridges in Norway are presented. This review paper gives an overvi...
K-C Mahnert, U Hundhausen