Your search resulted in 27 documents. Displaying 25 entries per page.
Microbiological degradation of wooden piles in building foundations
1988 - IRG/WP 1370
White rot, soft rot and bacterial attack have been detected in softwood piles under buildings. In some cases bacteria were found to be the main degradation organisms in the studied piles. The water content of degraded piles was very high. The compression strength was quite low also in the piles deteriorated by bacteria. The density of wood was very variable, and the degree of degradation could not be evaluated according to density analyses.
L Paajanen, H Viitanen
Studies on the preservation of structrual plywood - Part 1: Decay resistance of structural plywood
1974 - IRG/WP 238
The weight loss and the decreases in the compression strength and in the modulus of elasticity were measured to determine the decay resistance of structural plywood (lauan). Test pieces (50x25xA mm³) were exposed to the wood destroying fungi (Coriolus versicolor and Coriolellus palustris) for 2-3 or 2-4 months. After exposure, the measurement of the compression strength was carried out on the pieces of different thickness (A = 6,12 and 18 mm) and different fibre direction of the face veneer (0°, 45° and 90° to the long side of the test piece). The results obtained were as follows: 1.: The weight loss was small. The greatest weight loss was 9.4% on decaying by Coriolellus palustris for 4 months. 2.: The decreases in the compression strength and in the modulus of elasticity were greater than the weight loss. On decaying by Coriolellus palustris for 4 months, the ratio of decrease of the compression strength was 75% (6 mm - 0°). 3.: For differences of the thickness and of the fibre direction, the weight loss and the decreases the modulus of elasticity in the compression strength and in the modulus of elasticity showed tendencies in order 0° > 45° > 90° and 6 > 12 > 18 mm. 4.: According to the experiment, the face veneer is liable to be easily attacked by the wood destroying fungi, but the decrease in the compression strength was great. So, the face veneer and the cross section should be protected with preservatives for structural use.
K Minami, Y Kenjo, S Sugiyama
Use of Transverse Compression Properties as a Measurement of Wood Biodeterioration, Part 1 of 2 - Effect of White-Rot on Yellow-Poplar
2002 - IRG/WP 02-40239
The soil block and agar block test methods are used extensively as a screening process for potential and modified wood preservatives. The extent of decay in standard screening tests, indicative of preservative efficacy, is currently based on mass loss. Mass loss techniques, due to their limit of sensitivity in detecting significant mass loss vis-à-vis decay, require an extended fungus exposure period of the test specimens. Alternatively, an analysis of the effects of decay using mechanical loss test methods offer the possibility to significantly decrease the amount of time required to perform screening tests. Since a reduction in mechanical properties is continuous from the onset of decay, the exposure period of test specimens used in mechanical loss analysis is limited only by the sensitivity of the test apparatus to measure significant mechanical property loss. In the present study, the use of transverse compression, both radial and tangential, was evaluated as a method to quickly, and accurately, measure the extent of decay in thin yellow-poplar wafers exposed to a white-rot fungus in a soil block test. Within transverse compression, two properties of mechanical loss, compression strength at 5 % strain and modulus of elasticity to proportional limit were compared. While both methods of mechanical loss analysis proved to be a much quicker in determining significant decay than did mass loss, elastic loss appeared to offer a more accurate means of distinguishing the outset of significant decay than did strength loss.
S Janzen, D D Nicholas
Accelerated laboratory soil contact decay test using soil amended with composted wood
2004 - IRG/WP 04-20284
The effect of amending soil with wood compost on the decay rate of wood wafers in contact with the unsterile soil, as measured by radial compression strength loss, was explored. It was found that the addition of composted wood to the soil significantly increased the wood decay rate. The reason for this acceleration in wood decay is not entirely clear, but appears to be at least partially associated with the fungal inoculum provided by the wood compost. These results indicate that this method may be useful in the development of accelerated soil contact decay tests.
D D Nicholas, H Borazjani, T Schultz
Strength properties of preservative treated pine and spruce wood after super-heated steaming
1984 - IRG/WP 3313
Possible changes of strength properties of CCF pressure impregnated pine and spruce with subsequent steaming at 110°C respective 120°C for 30 min were examined. For spruce analysis of variance indicated that none of the processes had a significant effect on bending strength, compression strength and the corresponding modulus of elasticity as well as on impact bending strength and shear strength radial resp. tangential to the grain. For pine no changes in the bending strength and the compression strength could be detected. The impact bending strength of unsteamed or steamed impregnated samples decreased with 12% compared to non-treated controls due to the brittleness of the salt-impregnated timber. It could be proved that neither steam treatment of 110°C nor of 120°C for 30 min. alone causes a significant change of strength properties of pine and spruce. Arising variations can be explained from anatomical wood properties as well as salt deposits in the samples as a consequence to impregnation.
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 bacterial attack to be dominant in the secondary cell walls of both severe and mild compression wood. However, in some cases middle lamella was also degraded, which suggests that other forms of microbial attacks, such as bacterial tunnelling, were also present. Bacterial erosion in the severe compression wood was mainly confined to the inner part of S2 layer whereas in the mild compression wood it also extended into outer part of S2 and the S1 layer. The extent of erosion correlated to the differences in the amount and distribution of lignin, particularly in the outer S2 layer between the severe and mild compression wood cells. These features are compared with the degradation of normal Pinus wood.
Yoon Soo Kim, A P Singh
Bacterial degradation of Pinus radiata compression wood
1996 - IRG/WP 96-10153
An inspection of twelve year old, CCA-treated Pinus radiata wood from an industrial cooling tower showed extensive surface decay of wood. Electron microscopic examination of decaying compression wood indicated that compression wood cells were attacked exclusively by bacteria, which were of erosion and tunnelling types. As compared to the normal wood, compression wood appeared to be more resistance to the bacterial attacks present. The highly lignified outer S2 wall and the middle lamellae in the compression wood tracheids were resistant to erosion bacteria, and were only occasionally attacked by tunnelling bacteria. These observations are discussed in relation to the information available on the structure and chemical composition of compression wood.
A P Singh, R N Wakeling
Use of compression strength loss for measuring decay in the soil block test
1996 - IRG/WP 96-20083
The possibility of using radial direction compression strength of wood, rather than mass loss, was evaluated for both a brown-rot fungus (Gloeophyllum trabeum) and white-rot fungus (Trametes versicolor). With untreated pine wafers (5 x 19 x 19 mm³ - l x r x t) exposed to Gloeophyllum trabeum in a soil block test for five days, the compression strength loss was nearly 50% compared to a 5% mass loss. For Trametes versicolor the compression strength loss after 14 days was 25% compared to 0% mass loss. Both CCA and didecyldimethylammonium chloride treated wafers were evaluated against these fungi in the soil block test using both four and six weeks exposure periods. It was found that the toxic threshold values were approximately the same when determined by both compression strength loss and weight loss. However, more definitive toxic threshold values were obtained with compression strength loss. In comparing data from the four and six week exposure times for Gloeophyllum trabeum, it was found that lower toxic threshold values were consistently obtained for the former, regardless of whether compression strength loss or mass loss data was used. Based on the results of this study it appears that compression strength is a much better method for evaluating decay in the soil block test.
D D Nicholas, Zhongwei Jin
Methods for improving preservative penetration into wood: a review
2002 - IRG/WP 02-40227
Pressure treatment technologies have been available since the mid-1830's, but the processes used for wood treatment are still largely unable to overcome the fundamental limitations of flow through semi-permeable pit membranes. Instead, methods have arisen that attempt to improve treatability of the wood including incising, compression rolling, through boring, or radial drilling. Other approaches have altered the characteristics of the treatment fluid primarily by reducing viscosity. None of these methods has been completely successful. This paper reviews the methods employed to improve preservative penetration in wood and outlines research needs for addressing treatment of refractory wood species.
J J Morrell, P I Morris
Effect of compression wood on leaching of chromium, copper, and arsenic from CCA-C treated red pine (Pinus resinosa Ait.)
2000 - IRG/WP 00-30232
In this study, the effect of compression wood formation on the release rate of chromium, copper, and arsenic elements from red pine (Pinus resinosa Ait) was investigated. Wood blocks from red pine containing compression and normal wood portions were treated with a 1.0% CCA-C solution and were then allowed to fix at 23 ± ??2°C (74 ± 4°F) for 0, 6, 24, 48, 96, 192, and 336 hours. After each fixation period, the blocks removed from the conditioning room were subjected to 336 hours of leaching. Less chromium and copper elements were released from the compression wood blocks. For chromium, the biggest effect occurred after the 192- and 336-hour fixation periods. In the normal wood blocks fixed for 336 hours, the average chromium release rate after 6 hours of leaching was almost five times greater than that of blocks containing compression wood. Copper and arsenic release was also affected by compression wood, but for these two elements, the effect diminished during the later stages of fixation.
S N Kartal, S T Lebow
Nondestructive assessment of biodegradation in southern pine sapwood exposed to attack by natural populations of decay fungi and subterranean termites
1994 - IRG/WP 94-20042
Field methods for evaluating decay resistance of experimentally treated materials lack a means for quantitative measurement of residual strength. Quantitative relationships between speed of impact-induced waves travelling parallel to the grain and residual compressive strength have been demonstrated in softwood attacked by brown rot-decay fungi, but the effects of termites have not been documented. We tested southern pine sapwood stakes that were vertically inserted for one-half their length in soil in a southern pine forest in southern Mississippi. The results showed that measurement of both speed and attenuation of a reciprocating impact-induced wave will yield quantitative information on extent of total biodegradation in southern pine sapwood, independent of organism causing the damage.
R C De Groot, R J Ross, W Nelson
Determination of toxicity data for preservatives against Basidiomycetes by measuring the reduction in compression strength of wood
1988 - IRG/WP 2297
Blocks of Pinus radiata D. Don were treated to 12 retention levels with CCA and NaPCP. These were exposed for 12 weeks in agar jars to the dry rot (brown rot) Serpula lacrymans (Schum. ex Fr.) S.F. Gray. After mass loss determination, the same blocks were tested for reduction in compression strength parallel to the grain. Using both these parameters, together with interpolated 6 week strength loss data, toxic values (in accordance with the Polish standard procedure) and toxic limits (in accordance with the British standard) were calculated. The differences between efficaceous and non-efficaceous retentions of the two preservatives was greater for strength reduction data than for mass loss data. Reconsideration of the use of compression strength, as an alternative to mass loss measurements, is recommended
J Wazny, J D Thornton
Decay rates and strength and stiffness loss in foundation beams
1992 - IRG/WP 92-1563
The TNO Centre for Timber Research has executed an extensive research programme into the rate of decay in foundation beams, as a result of lowering of ground water tables. The aim of the research was to develop a method, predicting the decrease in strength and stiffness in beams, due to wood decay during drytime of foundation beams. With the calculated extremes in decay, the damage caused by local settlements of the foundation can be estimated. Though this research deals with untreated timber only, the results yield information which may be used for methods of testing treated timber in ground contact. From 1987 to 1989 literature studies and field inspections have been evaluated, and the most important influencing factors were described. In the following laboratory research the aim was, to quantify the influence of these factors (wood species, dimensions, age, soil wetness, temperature, fluctuation of water) on the decay rate. The rate of decay was measured by mass loss after one year of exposure in a wet but aerated soil, using pine and spruce in different dimensions. For part of the specimens, decrease in strength properties was also measured. Results indicate, that for timber with high moisture contents (over 80%), the decay type is dominated by softrot (95%) and is mainly determined by the surface/volume ratio. The relation between mass loss and loss of strength and stiffness was determined. These results will be used for calculating the deformation of foundation.
P Esser, H S Buitenkamp
A comparison analysis of eight strains of Serpula lacrymans (Schum. ex Fr.) S.F. Gray
1991 - IRG/WP 2362
Investigations were previously carried out to compare eight strains of Serpula lacrymans (Schum. ex Fr.) S.F. Gray (some used in various countries as standard test strains): FPRL 12C (England), FPRL 12E (Germany), Warsaw III (Poland), HFP 7802 (Japan), DFP 16508, 16509, 16521 and 16522 (Australia). Studies included growth rate and dry mass of mycelium, decay capacity, reduction of compression strength, toxic values of CCA and NaPCP tested with agar-plate method (ED50, ED100, LD100) and a modified agar-block method using mass-loss and reduction of compression strength criteria. All of the data obtained are presented here together for the first time, in both table and graphic formats. Further comparison between these results will be presented later (in the final part of the series in 'Holzforschung').
J Wazny, J D Thornton
Development of a novel treatment process and its applications
1998 - IRG/WP 98-40111
An efficient treatment process called "Isostatic Compression Recovery (ICR) Process" for impregnating liquids into wood has been developed. The process comprises steps of isostatic compression of wood in the liquid at temperatures above its softening temperature and subsequent recovery of its original volume under liquid pressure. A large amount of surrounding liquid is absorbed into the wood in the process of volume relaxation through end surfaces. The process is suitable to uniformly impregnate wood with chemicals which are either liquid or form solutions stable at the treatment temperature. As an example of application of the ICR process, impregnation of Japanese cedar (Cryptomeria japonica) and Radiata pine (Pinus radiata) lumber with borates at high retention is demonstrated , where as much as 60% w/w of borate is impregnated in Japanese cedar lumber in a single treatment.
T Arakawa, M Funato, A Hoshino, T Muraki
Effects of sodium hypochlorite on compression strength and copper retention of spruce wood treated with copper azole and alkaline copper quat
2007 - IRG/WP 07-40362
This work investigates the effects of sodium hypochlorite on compression strength values and copper retention ratios of refractory spruce wood (Picea oriental L.) treated with the waterborne preservative Copper Azole, (CBA-A, Tanalith-E 3492) and alkaline copper quat (ACQ-2200). Before the copper azole and alkaline copper quat treatment, the samples were immersed in 500 ml of sodium hypochlorite solution for three different durations (2, 4, and 6 hours). A 2 % active ingredient solutions of CBA-A and ACQ were applied for use in vacuum treatment of the sapwood samples. Average copper contents of the specimens were higher than that of the control groups except of the 6-hours sodium hypochlorite treatment in ACQ impregnation. The highest copper value was seen in the variation the 6-hours sodium hypochlorite treatment in the CBA-A impregnation. Compression strength values generally slightly reduced compared to the control groups especially in ACQ impregnation.
S Yildiz, E Dizman, A Temiz, Ü C Yildiz
Primary Study on Compressed Preservative-treated Wood (CPW) for Outdoor Applications
2008 - IRG/WP 08-40412
In this study, the compressed wood samples pre-treated with hot water bath or water spraying were immersed in the ammoniacal copper quat –type D (ACQ-D) preservative solution to get compressed preservative-treated wood (CPW). The liquid absorption and the recovery rate of compression deformation of the compressed wood was determined, as well as the surface hardness, the distribution of density and CuO retention in the thickness direction of CPW. The results showed that: (1) the recovery rate and liquid absorption were closely related with each other. Generally a higher recovery rate of compressed deformation corresponded to a higher liquid absorption; (2) the liquid absorption of compressed wood with pre-treatments was about 1.5 times of the untreated control samples, and the surface hardness of the CWP prepared with this method was 3~4 times of that of the untreated control samples; while the corresponding values of those without pre-treatments were more than 2.0 times and about 1.6 times, respectively; (3) the density distribution of the CWP with pre-treatments were much more uniform in the thickness direction, additionally the retention of CuO appeared to be much higher and had a clear trend of higher retention on surfaces and lower inside compared with that of the CWP without pre-treatments. In conclusion, the CPW prepared in this study can achieve both surface densification and preservation, which are suitable for outdoor applications.
Jinzhen Cao, Jia Mao
Preliminary investigation of biological resistance, water absorption and swelling of thermally compressed pine wood panels
2008 - IRG/WP 08-40396
Wood can be modified by compressive, thermal and chemical treatments. Compression of wood under thermal conditions is resulted in densification of wood. This study evaluated decay and termite resistance of thermally compressed pine wood panels at either 5 or 7 MPa and at either 120 or 150?C for one hour. The process caused increases in density and decreases in thickness of the panels; however, laboratory decay resistance tests using one brown rot fungus and one white rot fungus revealed that thermally compressed wood was not resistance against the fungi tested. More interesting results were found in laboratory termite resistance tests. As pressure and temperature increased up to 7 MPa and 120?C, mass losses in the specimens decreased gradually when compared to control specimens. However, the specimens compressed at 7MPa and 150?C showed higher mass losses in comparison with the specimens compressed at 7 MPa and 120?C. Decay and termite resistance of such materials is still controversial even though density is improved under thermal processing.
Ö Ünsal, S N Kartal, Z Candan, R Arango, C A Clausen, F Green III
Effects of Murgul Copper Process flue gases (SO2) on compression strength parallel to the grain of Beech (Fagus orientalis Lipsky.) wood
2008 - IRG/WP 08-40404
In this study was investigated the effect on the compression strength parallel to the grain as mechanical properties of Fagus orientalis Lipsky. wood exposed to SO2 gas and non-exposed. In the experiments the two of four (total) were obtained from Artvin-Ortaköy region and the other two from Artvin-Murgul region. The compression strength parallel to the grain was calculated at the compare of trees are taken from two distinct region. The obtained data of SO2 exposed specimens were compared with non-exposed ones. According to the obtained data of this study suggestions were given. At the end of study no effect of SO2 gas has been determined on the compression strength parallel to the grain of Fagus orientalis Lipsky. wood.
N Ay, E Topaloglu, A Uncu
Measurement of wood decay by dynamic MOE in an accelerated soil contact test
2008 - IRG/WP 08-20390
Current laboratory and field testing of preservatives involves various techniques to determine the extent of fungal attack, including visual inspection, mass loss, and static bending and compression strength measurements. The objective of this study was to compare decay measurement by conventional compression strength versus dynamic MOE, employing small wood stakes in an accelerated laboratory soil-contact wood decay test. The maximum decay was generally observed close to the center of the stake. An average correlation of 0.884 was observed between the average compression and dynamic MOE strength losses.
Gan Li, D D Nicholas, T P Schultz
Evaluation of ACQ-D treated Chinese fir and Mongolian Scots pine with different post-treatments after 20 months of exposure
2010 - IRG/WP 10-30530
The performance of alkaline copper quat-type D (ACQ-D) treated Chinese fir (Cunninghamia lanceolata Hook.) and Mongolian Scots pine (Pinus sylvestris Linn. var. mongolica Litv.) stakes after 20 months exposure in Chengdu and Guangzhou of southern China were evaluated according to AWPA standard E07-07. The ACQ-D treatments used two concentration levels (0.5 and 1.0%) and four different post-treatments (air drying for 1 month, conditioning at 70°C, 80% R.H. for 24h, oven drying at 110°C for 24h, boiling in water for 15h), respectively. The field test results showed that the natural durability of Chinese fir is a little better than Mongolian Scots pine but the untreated sapwood stakes of both wood species were mostly destroyed after 20 months exposure. After ACQ-D treatment, the sapwood of both wood species showed much better biological performance. Among the four post-treatments, the oven drying method (OD) rated the worst by showing slight reduction in biological performance and the most obvious reduction in compression strength after exposure, while the other three post-treatments performed similarly. It suggested that both post-treatments of HC (conditioning in humidity chamber) and HW (hot water bath) could be good selections for accelerating copper fixation in ACQ-D treated wood. And also, Chinese fir from plantation forests could be a potential wood species for preservation.
Lili Yu, Jinzhen Cao, Wei Gao, Haitao Su
Effect of Nano-silver Treatment on Densified Poplar Wood Properties. Part Two: Spring Back, Compression set, Impact Load Resistance and Hardness
2011 - IRG/WP 11-40568
This paper is the second part of the study of applying nano-silver treatment before densification of poplar wood (Popolus alba). The specimens were prepared in four groups of: 1) nano-silver impregnated 2) water impregnated 3) dried with no impregnation and 4) the control specimens. The impregnation process was done by empty cell process. Then, the groups of 1 to 3 were compressed in a hot press at the temperatures of 150 and 175ᵒc for 1 and 4 hours. Spring-back, compression set, impact load resistance and hardness values of specimens were determined and all data were analyzed statistically. The measurements of mechanical properties were carried out according to ASTM D-143. The results showed that by nano-silver treatment, spring back, compression set and impact load resistance were improved, significantly. The best amounts of spring-back (0.24%) and compression set (35.26%) were seen in specimens which were impregnated with nano-silver solution and compressed at 175 for 4 hours. The best amount of impact load resistance (34915.0 J/m2) belonged to the nano-silver treated specimens which were compressed at 150 for 4 hours. The maximum amounts of hardness values (37.16 N/mm2) were related to the non-treated specimens which were compressed at 175 for 4 hours. On the whole, based on the results of part one and this one, applying nano-silver treatment can be resulted in obtaining optimal physical and mechanical properties in densified poplar wood. The results of this study will be useful for producing a novel densified wood which can be applicable for some structural uses such as flooring.
G Rassam, H Reza Taghiyari, B Jamnani, M Ali Khajeh
The assessment of biological and mechanical properties of wood treated with ionic liquids – N,N-dimethylamine and 1-decylimidazole derivatives
2012 - IRG/WP 12-40582
This paper presents the results of tests of the effectiveness of action of new imidazolium and bis-ammonium ionic liquids against Basidiomycotina and Ascomycotina wood-destroying fungi. All the investigated ionic liquids showed high fungicidal action against Coniophora puteana. In order to characterize the influence of ionic liquids on mechanical wood properties, the compression strength along the grain was investigated. The obtained results showed that impregnation of Scots pine sapwood with ionic liquid: [1,9-(2,8 dioxanenano]bis(dimethyloctylammonium nitrate) had no negative effect on the compression strength parallel to grain. The investigated compounds characterised by thermal stability, may be applied as biologically active components of wood impregnates in combination with other biocides.
Combined effects of thermal modification and ACQ-D impregnation on properties of southern yellow pine wood
2013 - IRG/WP 13-40637
In this study, samples of southern yellow pine sapwood were first thermally modified and then treated by the alkaline copper quat-type D (ACQ-D) wood preservative. Two heating temperature (180℃ and 220℃) and two concentrations of ACQ-D solution (0.9% and 1.35%) were used in the experiments. The combined effects of thermal modification and ACQ-D on leaching performance, mechanical properties and mold resistance of the treated wood were then investigated. The results of the experiments indicated that thermal modification increased the percentage of copper leaching and decreased the MOR and MOE of wood, and also it affected the compression strength parallel to grain. After the ACQ-D impregnation, the bending properties of thermally modified wood got lowered to some extent. The anti-mold experiment indicated that the ACQ-D impregnation could improve the mold resistance of thermally modified wood.
Wang Wang, Yuan Zhu, Jinzhen Cao
Estimation of wood degradation determined by visual inspection, mechanical testing and DNA characterisation – report after 3 years of exposure
2016 - IRG/WP 16-30700
The influence of two separate treatments, thermal modification and alkaline copper quaternary (ACQ, Silvanolin©) treatment, on fungal decay, visual disfigurement, deterioration in mechanical properties and fungal community structure was assessed on Norway spruce (Picea abies) and compared with the performance of two naturally more resistant tree species native to North America: Douglas fir (Pseudotsuga menziesii) and Western red cedar (Thuja plicata). Wood samples were exposed to environmental conditions and collected annually over three years. Samples were visually examined and rated for decay and disfigurement then evaluated to failure in three-point loading to determine flexural properties and, finally, DNA was extracted from the samples and analyzed to determine the fungal community present. As expected, there were substantial differences in visual ratings, fungal colonization and flexural properties. Further assessments are planned.
N Thaler, T Martinović, M Bajc, D Finžgar, H Kraigher, A Sinha, J J Morrell, M Humar