Your search resulted in 168 documents. Displaying 25 entries per page.
Some experiences with attack of microorganisms on wooden constructions supporting foundations of houses and bridges
1997 - IRG/WP 97-10232
Reconstructions of bridges and public buildings or damage of houses during the construction of subway lines in Berlin have led to a number of inspections of wooden foundations, mostly pine or spruce piles, representing service lives of between ca. 70 and 140 years. In all cases bacterial attack was found both in wood submerged in ground water and in surface water. The extent of deterioration diffe...
M Grinda
The effect of hemicellulose degradation on the mechanical properties of wood during brown rot decay
2001 - IRG/WP 01-20219
Incipient decay of wood by brown rot fungi causes measurable strength losses in wood before measurable weight loss occurs. Previous studies have shown that the high levels of strength loss that occur during incipient brown rot decay may be related to loss in hemicellulose. This paper investigates the effect of decay on hemicellulose composition and the relationship to the mechanical properties of ...
S F Curling, C A Clausen, J E Winandy
Field stake test assessment with the Pilodyn
1980 - IRG/WP 2136
The Pilodyn, which was originally developed to estimate the degree of soft rot in wooden poles, was thought to have potential for giving a quantitative measure of the extent or depth of decay in field test stakes. In the present work a 2-joule Pilodyn with 2.0-mm diameter pin was used in an attempt to limit depth of pin penetration (to 10-15 mm) without reducing scale sensitivity. The results show...
M E Hedley, R W Naish
Paper for discussion - Incising of spruce to improve preservative penetration
1973 - IRG/WP 318
Large quantities of whitewood or Norway spruce (Picea abies) are regularly imported into the United Kingdom from continental Europe. In addition, increasing amounts of Sitka spruce (Picea sitchensis) are likely to become available over the next decade from the Forestry Commission. In many ways spruce is a good structural timber, eg it is relatively cheap and easily available, it has adequate stren...
W B Banks
Acetylated solid wood. Laboratory durability test (part 2) and field trials
1995 - IRG/WP 95-40048
Degradation of acetylated beech, pine and poplar by soft rot fungi was related to strength loss in a laboratory test. No strength loss was noticed for poplar acetylated to a weight percent gain (WPG) of more than 11.2% and beech with a WPG of 12.8%. Several field trials were set up to determine the durability of acetylated products in practice. They included a field test to determine the durabilit...
E P J Beckers, H Militz, M Stevens
The degradation of wood surfaces by water
1984 - IRG/WP 3289
Thin radial/longitudinal sections (~100 µ) of Scots Pine (Pinus sylvestris) and lime (Tilia vulgaris), were exposed to deionised water over the temperature range 25-65°C. Losses in wet tensile strength and toughness occurred rapidly at temperatures from about 50°C upwards. After about 2 months' exposure pine lost some 10-30% of its tensile strength and 20-60% of its toughness. For lime...
W B Banks, P D Evans
Effect of Scytalidium lignicola on decay resistance and strength of wood
1994 - IRG/WP 94-10061
We reported previously that in laboratory tests, pretreatment of Douglas-fir and Southern Pine blocks with Scytalidium lignicola prevented decay. In the present work, we determined 1) the ability of Scytalidium lignicola to colonize and survive in wood exposed in the field, 2) the decay resistance of blocks removed from previously treated Scytalidium lignicola wood and 3) the effect of Scytalidium...
T L Highley
The effect of extent and location of decay on strength loss in constructional timber
1994 - IRG/WP 94-30039
Radiata pine heartwood billets, 50 x 100 x 1000 mm³ were end-sealed and treated with copper-chrome-arsenate preservative (NZ Type I) to a range of retentions and penetration patterns. Cross-sections, 10 mm thick, were cut from the centre of each billet and used for determination of preservative distribution, for preservative analysis and for decay tests. The decay test consisted of laying samples...
M E Hedley, H Bier
Effects of alkali treatment on some mechanical and chemical properties of creosote treated oaks
1991 - IRG/WP 2366
To date, there is a lack of information on the effects of chemical treatment on the performance of creosote preservative treated oak sleepers. This factorial experiment was designed to analyze three main effects: species (Quercus alba and Quercus rubra) creosote treatment (treated and untreated), and alkali (NaOH) soaking (0, 1, and 10 percent). The modulus of elasticity (MOE) and fiber stress at ...
P Chow, A J Reinschmidt, E J Barenberg, L C Chang
A laboratory technique to measure the performance of preservative treated hardwoods in ground contact
1982 - IRG/WP 2172
A laboratory technique to measure the performance of preservative treated timber in ground contact is described. It uses partially sealed blocks of timber which are treated, leached and sawn into small stakelets for soil exposure in a fungal cellar. Performance is monitored by the loss of static bending strength with time, and a simple apparatus for measuring the deflection of a stakelet under a l...
E F Baines
Application of a novel strength evaluation technique during screening of wood preservatives
1986 - IRG/WP 2262
The effectiveness of CCA and ACA in treated aspen mini stakes tested using a novel bag procedure, with unsterile soil fortified with Chaetomium globosum and Ceratocystis albida, is reported. Good agreement between toxic limits determined using the standard weight loss procedure, and those determined by the strength technique were found, with some indication that the strength loss method is more se...
J N R Ruddick
The effect of primary blue-staining fungi on the strength properties of Scots pine sapwood
2004 - IRG/WP 04-10515
The fungi action may have influence on wood properties especially Basidiomycotina fungi causing wood decay. The investigation of influence of fungi causing mainly wood discoloration and disfigurement on wood properties is still in development process. There were determined the differences between the bending strength, the compression along the grains and impact strength of control and blue stained...
A Fojutowski
Degradation features of waterlogged archaeological compression wood
1998 - IRG/WP 98-10258
The degradation characteristics of waterlogged archaeological compression wood excavated in South Korea were examined by transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). Degradation of Pinus compression wood occurred mainly in the inner part of S2 layer. In contrast, the outer part of S2 layer remained relatively intact. CLSM and TEM showed the erosion type of ...
Yoon Soo Kim, A P Singh
In-ground field test of scots pine (Pinus sylvestris L.) sapwood and heartwood
2004 - IRG/WP 04-30336
Scots pine (Pinus sylvestris L.) sapwood and heartwood stakes treated with CCA-C and creosote were tested for one- year in a field plot in Bartın region in Turkey.
Scots pine heartwood stakes had lower preservative retention than sapwood stakes. Bending strength of the stakes was decreased after impregnation and one-year field test. While the bending strength of untreated sapwood was 93....
H Sivrikaya, H Hafizoglu
The use of spruce for transmission poles
1973 - IRG/WP 326
A series of preservative treatments with creosote using Lowry and Rueping schedules was undertaken. From these treatments the most suitable impregnation conditions for water stored Sitka spruce (Picea sitchensis) and Norway spruce (Picea abies) transmission poles were determined. Preservative distribution and permeability values for poles of both species were used to decide the optimum season and ...
J A Dunleavy, D J Balfe, J P Prendergast
Effect of vapour boron treatment on mechanical properties of wood based board materials
1992 - IRG/WP 92-3727
The mechanical properties of Medium density fibre board, Chipboard and Oriented strand board were investigated after treatment to two retention levels of boric acid applied as a vapour phase system. A range of mechanical properties were investigated. The vapour boron treatment does not have any significant effect on most of the mechanical properties of the boards. The exception is a reduction in i...
R Hashim, D J Dickinson, R J Murphy, J Dinwoodie
Rapid loss of lignin at wood surfaces during natural weathering
1992 - IRG/WP 92-2390
Thin veneers of radiata pine (Pinus radiata D. Don) were exposed to natural weathering over a period of 30 days. Incident UV radiation was monitored at the test site. FTIR internal reflectance spectroscopy was used to study the chemical changes taking place at the veneer surface during weathering. Spectra obtained show that after only 3 days exposure there was substantial delignification at veneer...
P D Evans, K J Schmalzl, A J Michell
Evaluation of a utility pole inspection procedure
1996 - IRG/WP 96-20084
Methods were developed and are currently being utilized to appraise residual strength of utility poles based on visual assessment of increment cores. Strength tests, mycological descriptions and anatomical analyses were performed on eight utility poles taken out of service and one new (never in service) pole. Samples were obtained from increment cores removed from 6 levels in the pole: 2 feet, gro...
S E Anagnost, C J K Wang
Supercritical fluid treatment: Effects on bending strength of white spruce heartwood
1993 - IRG/WP 93-20008
The effects of supercritical carbon dioxide on wood strength were evaluated using white spruce heartwood, a species known to be especially susceptible to collapse during exposure to higher pressures. The effects of pressures of 2000 or 3600 psig and temperatures of 40 or 80°C were evaluated using 30 or 60 minute exposure periods. No significant differences were noted in modulus of rupture or modu...
S M Smith, J J Morrell, E Sahle-Demessie, K L Levien
Fundamentals on steam fixation of chromated wood preservatives
1988 - IRG/WP 3483
Weathering of treated wood directly after impregnation leaches up to 2% of copper-chromate-containing wood preservatives. Almost total fixation of Cr+6 is achieved by steaming the treated wood at 100°C to 120°C, preferably 110°C. To initiate such spontaneous fixation 85°C to 90°C inside the wood are essential, which requires heating times ranging from 20 to 80 min, depending on timber species...
R-D Peek, H Willeitner
The comparative resistance to fungi of the wood munika (Pinus heldreichii Christ.), fir (Abies alba Mill.) and spruce (Picea excelsa Poir.) compared with Pinus sylvestris L. and some physical and mechanical characteristics of munika
1981 - IRG/WP 1129
The munika (Pinus heldreichii Christ.) is situated primarily in the Balkans, and partially in the south of the Apenine peninsula. As an endemic species, with a very little annual increment, it has not been used enough as a timber for mechanical conversion up till now, although the oldest trees can grow to 27 m in height, with a diameter at breast height of about 60 cm. According to data of many Ba...
M Petrovic, M Miric
Investigation of the suitability of silver fir (Abies alba Mill.) for thermal modification
2004 - IRG/WP 04-40275
In this study the suitability of silver fir (Abies alba Mill.) was examined for thermal modification. Comparative experimental investigations were performed with silver fir and Norway spruce (Picea abies Karst.) after thermal treatments. Besides properties, which characterize the quality of heat treatments, like dimensional stability and resistance against fungal attack, strength properties of the...
C Brischke, A O Rapp
Standardization of preservative treated timber species for conductor, insulator and transformer packing of REB
1996 - IRG/WP 96-40071
In order to resolve the post landing failure problem of wooden packing for conductor, insulator, transformer of REB, the names of the suitable timber species from different parts of the world, irrespective of countries of origin have been standardized along with their strength and treatability grades. The CCA treatability of some Pakistani timber species have been presented for example which was t...
A K Lahiry
Preservative treatment of common timbers and bamboos of Bangladesh for rural electrification infrastructure
1998 - IRG/WP 98-40104
Researches revealed new treatment grades, treatment groups, grading groups, natural durability grades, strength groups and a new preservative combination for remedial treatment and sterilization of most common timbers and bamboos of Bangladesh. The obtained findings are applicable for equivalent timber species having equivalent climatic condition. Sapwoods are always perishable and timbers with wh...
A K Lahiry
Applicability of supercritical carbon dioxide to the preservative treatment of wood-based composites
2001 - IRG/WP 01-40199
Treatability of five structural-use wood-based composites (medium density fiberboard, hardwood plywood, softwood plywood, particleboard and oriented strand board) was evaluated when supercritical (SC) carbon dioxide (CO2) was used as a carrier solvent. Treatments were conducted at three temperature 32 levels (25, 35 and 45°C) and two pressure levels [80 kgf/cm2 (7,845 kPa) and 120 kgf/cm2 (11,768...
M Muin, A Adachi, K Tsunoda