Your search resulted in 16 documents.
Quasi-in-situ durability tests on oak timber bridges
2013 - IRG/WP 13-20510
This study aims on developing a method for determination of wood durability on samples taken from real structures in service. Therefore quasi-in-situ durability tests have been conducted exemplarily on timber bridges made from English oak (Quercus robur L.). Drilling cores were found to be a feasible alternative to standard specimens for laboratory durability tests against pure cultures of Basidiomycetes and against soft rot and other soil-inhabiting micro-organisms in unsterile soil. Drilling cores were therefore taken from various components of six bridges, which were similar in design, but differed in previous service life. The determined mass losses due to fungal decay were compared with the level of damage of the studied bridge components. The results indicated that the material-inherent resistance was responsible for damages rather than poor details of the construction. The methodological approach should be seen as quasi-in-situ resistance tests providing further knowledge about the relationship of timber in service and under ideal laboratory test conditions.
C Brischke, C J Behnen, M-T Lenz, K Brandt, E Melcher
A novel method for delivering fluids into bolted wooden components.
2004 - IRG/WP 04-40280
The paper describes the development of a washer that enables fluids such as wood preservatives and adhesive resins to be delivered to bolted wooden components in-situ. The system was developed to meet the criteria of low cost and the ability to tolerate inaccurate drilling of holes in the wooden members.
G S Sawyer, B Tole
A case for adopting a standardised protocol of field and laboratory bioassays to evaluate a potential soil termiticide
2003 - IRG/WP 03-20275
The rationale for adopting a new approach to the field testing of potential soil termiticides is advocated on the grounds that current testing methods are limited to termite bioassays and do not address quantitatively the persistence and bioavailability of soil termiticides to foraging subterranean termites over time and in different soil types. Furthermore, the present testing regimes assume field situations of uniform high termite hazard across field sites. Our testing procedures require the random sampling of soil cores from test soil pads (500 x 500 mm) at several geographically different locations. The soil cores from treated and untreated soil pads are returned to the laboratory and the soil residues in half of the samples examined for each year of test by gas chromatography. The bioavailability of termiticide residues in the remaining soil samples are evaluated by termite bioassays using the field collected subterranean termite, Coptotermes acinaciformis (Froggatt). Both tunnelling distance and mortality are used as indicators of termiticide activity and availability. This paper compares the traditional soil test methods with our new approach, which addresses the problems of security with longevity of test, variability of termite hazard levels at different field sites, and a practical method for managing variables in assessing potential soil termiticides. Importantly, this technique prevents the direct destruction of natural populations of subterranean termites or the indirect contamination by contact from soil residues of termiticides applied in and around active termite colonies.
J R J French, B M Ahmed
A novel device for detecting internal defects in wooden poles
1989 - IRG/WP 2329
The diagnosis of internal defects caused by termites and decay in hardwood transmission poles has been investigated using a novel Automatic Feed Drill (AFD) pole testing device. Internal defects were recognised by changes in drill feed-rate as the automatic air-driven drill traversed its 100 mm working stroke. The instrument is portable, simple to operate and recognises defects instantaneously. Tests carried out on pole material in the laboratory and the field showed that the instrument gives quick and accurate measurements of internal collapse and weakness in wood at the groundline zone.
R A Eaton, R S Johnstone
Studies on the preservative treatment of round bamboos by a new technique
1989 - IRG/WP 3536
Nature has offered a versatile and cheap material bamboo, which is generally found to grow principally in forest areas from sea level to about 400 m wherever suitable combination of ecological factors prevail. This potential renewable natural resource has been since times immemorial, exploited by mankind for a variety of purposes specially in developing countries like Asia, Africa and South America. Bamboo is very well known for its remarkably fast growth. The size and yield of bamboo depends upon several factors like species, soil, climate etc. For example, D. gigantius gives culm 35 m long and 20-25 cm in diameter, Chimoni bambus densifolia culm is hardly 90 cm long and 0.85 cm in diameter. While species like D. strictus are almost solid (specially in dry areas) most of the other species are hollow with wall thickness varying (0.62-0.85 cm). Bamboo possesses adequate strength which compares favourably with some conventional species like sal (Shorea robusta) and teak (Tectona grandis). Bamboos and reeds are said to be the oldest and major building materials specially for rural areas throughout tropical and subtropical regions. It is reported that more people live in houses made of bamboos and reeds than in houses of any other material.
V R Sonti, S Sonti, B Chatterjee
Microscopic analysis of southern pine utility pole core segments
1992 - IRG/WP 92-1542
Fifteen macroscopic core descriptive categories were evaluated by microscopic analysis for accuracy in detecting decay and judging decay severity. Five categories were good indicators of decay as decay was detected in 28 of 48 samples. Five categories were possible indicators of early decay as decay was detected in 6 of 40 core segments and an additional 18 contained hyphae. The remaining five categories were considered indicators of sound wood as no decay was detected in those samples. Macroscopic features which frequently indicated decay were compaction and discoloration. However, discoloration was often misjudged or confused with preservative treatment. Identification of fungal isolates will add valuable information. Thirty-four of 152 core segments from fifteen southern pine utility poles contain soft rot (25), white rot (3) or both (6). Decay detection was improved by using the fiber suspension technique. Soft rot was detected from 1 foot below to 4 feet above groundline and as deep as 15 cm from the pole surface.
S E Anagnost, C J K Wang, M Wright
The influence of drilling patterns on the distribution of toxicants from Polesaver Rods in hardwood poles
1994 - IRG/WP 94-30051
Polesaver Rods are solid rods of wood preservative that are used as a groundline maintenance treatment to control biodeterioration in hardwood transmission poles in Australia. The rods are inserted in holes that are drilled in a prescribed manner to distribute the toxicants into the critical groundline region of the poles. To determine the influence of drilling patterns on the distribution of toxicants five test drilling patterns, including the prescribed method, were assessed in unseasoned pole-size stubs of tallowwood (Eucalyptus microcorys F. Muell). The distribution of toxicants was visually appraised and is reported for three of the drilling patterns. The results indicate that drilling patterns influenced the toxicant distribution. Two of the trial patterns appeared to provide improved distribution of toxicants for specific applications when compared with the prescribed pattern.
W D Gardner, C N McEvoy
Preservative treatment of round bamboos by a new technique - Some further studies. Part 1
1990 - IRG/WP 3607
In general, the easy susceptibility of bamboos to wood destroying agencies is a major constraint in its rational utilisation. This is more so in tropical countries like India where wood destroying agencies are quite active. In an earlier publication, it was reported that round bamboo specimens of Bambusa balcooa, having three nodes, could be satisfactorily treated by CCA by a new technique developed at the R & D laboratories of Ascu India. It was also stated that further experimental work was in progress with longer specimens. Details of the results obtained so far are reported in this paper.
V R Sonti, B Chatterjee
Field Tests on Poles. A report from practice
2006 - IRG/WP 06-20343
A routine field inspection of some 1000 creosote poles during summer 2005 in northern Jutland, Denmark. The routine inspection was done by hammering, Pilodyn testing and taking core samples with a Matson Borer. Additionally a drill resistance measurement was done with a device consisting of the drill machine with a long, flexible steel needle with 1,5mm diameter and the measuring computer/battery-block (“Resistograph”). The needle is drilled with constant speed into the wood and the power uptake of the drill is measured. It showed excellent features for the investigation of poles or other wooden elements in service. But it is time consuming and heavy, thus, the old hammer method revealed to be still the fastest possibility to find out questionable poles. Thus, as an additional tool the Resistograph can be used at least on poles that were found to be in questionable condition and also on poles of particular importance, for example near roads or other places where a failure could lead to severe damages.
A Peylo, C-G Bechgaard
Brief introduction of a research project on the wood materials from an ancient Byzantine port unearthed during drilling for underground rail tunnel in Istanbul
2008 - IRG/WP 08-10641
A research project has been recently started to evaluate some properties of wooden materials from the biggest port of ancient times called Port of Theodosius I in Istanbul, Turkey. The ruins of the ancient Byzantine port during the excavations were recently uncovered in the Yenikapi site where an underground rail tunnel construction has been in progress in Istanbul. The wooden objects unearthed from the port are being subjected to anatomical examinations under light and photomicroscopes, chemical properties of the objects will be determined in comparison with recent wood samples, physical and mechanical tests will be performed and finally microbial properties will be investigated to show any possible decay zones in the samples. Preliminary investigations revealed that Quercus spp. and Cupressus spp. samples excavated at the site showed no distinctive decay zones; however, some soft zones were clear in the sapwood portions of the samples. Detailed examinations are in progress to evaluate microbial and anatomical properties of the samples in comparison with recent wood samples.
A D Dogu, C Köse, S N Kartal, N Erdin
Microwave Surface Modification of Radiata Pine Peeler Cores for Preservative Treatment
2009 - IRG/WP 09-40453
Radiata pine peeler cores are classified as a by-product derived from the cores of logs left over after the veneer peeling process. The core can be potentially developed for value added solid wood products as it is abundantly available and has a constant diameter. However, the core needs to be preservative treated because of low durability in ground contact. An additional problem is that the wood is primarily heartwood and difficult to impregnate with wood preservatives. Recently, microwave (MW) technology has been developed for improving the permeability of wood. Microwave energy absorbed by timber generates steam pressure within the wood cells and creates narrow micro voids in the radial-longitudinal plane. A several thousand-fold increase in wood permeability can be achieved in wood species that previously were considered impermeable. In Australia peeler cores measuring 130 mm in diameters need to be preservative treated to at least 8 -20 mm depth depending on the hazard class (above ground or ground contact) before being utilized. This means that the preservative is required to penetrate the surface only. A special microwave applicator (PC-1) that operates on a frequency of 2.45 GHz has been developed for timber surface treatment. The applicator has been designed and built based on computer modelling of the interaction between timber and microwave energy. A key aim of this research is to examine the effect of surface treatment using applicator PC-1 that meet peeler core preservative treatment standards. The methodology includes temperature distribution measurements in the peeler core after microwave heating and preservative distribution and uptake measurement after heating. The results show that after microwave treatment, the highest temperatures are recorded on the surfaces of the core. There is then a gradual decrease in temperature with depth in the timber. Experiments show that applicator PC-1 can modify radiata pine peeler cores to meet Australian Standards requirements. CCA uptake after pressure impregnation could be controlled to within the range between 94 to 314 L/m3 depending on the applied microwave energy (in the range of 55 – 90 kWh/m3) and processs parameters. Preservatives penetrate through the induced microvoids in the radial longitudinal direction of the wood to a limited depth of penetration depending on the intensity of power application. Control samples had an average uptake of 35 L/m3, which means microwave modified logs had 3-9 times higher uptake than the controls.
K Sugiyanto, G Torgovnikov, P Vinden
Chapter 11 - Preservation of talla bamboo
2007 - IRG/WP 07-10635-11
Researches revealed that the talla bamboo (Bambusa tulda Roxb.)) in Bangladesh could be full-cell pressure treated with CCA in green and dry conditions. The dry bamboo gives higher loading absorptions than green one when impregnated at same treating conditions. Also higher absorptions are obtained at nodes rather than internodes. Adequate penetration and retention results for ground and water contact uses are only possible by treating bamboos pre-dried to 10-15% MC. The green bamboo is easily treatable for indoor and overhead outdoor uses. The service life of this socio-economically important bamboo can easily be increased at least two times than nominal by CCA treating either green or dry bamboo. Two small holes made before pressure treatment in each internode will give split-free bamboo.
A K Lahiry
The case for using borates in termite control in tropical Australia
2011 - IRG/WP 11-30573
A brief historical overview of boron based wood preservatives efficacy against subterranean termite management worldwide, and in Australia, is presented. The boron based compounds to be used in H2 hazard conditions, may be applied as a surface treatment by dip, flood coat or spray, and rapidly penetrates to the centre of timber substrates, whether containing sapwood or heartwood. However, section 8, clause 8.2.2 (c) of the Australian Standard AS 1604.1-2010 bans the use of boron compounds for use in termite management north of the Tropic of Capricorn. In this paper we argue the case for the adoption of boron compounds in termite management systems north of the Tropic of Capricorn, as either single or multi-component biocide systems. We have searched the numerous papers for “boron and termites” in the IRG data base since 1969 to the present, and other scientific evidence from a consistent science worldview; our own results of boron against termites in our ‘whole-of-house’ above-ground and in-ground field test using simulated houses and wood stakes respectively at Nhulunbuy, Arnhem Land, in tropical Australia. In these test sites, active populations of Coptotermes spp., Heterotermes spp., Nasutiterme spp., Schedorhinotermes spp., and Mastotermes darwiniensis, were present. After 5 years in the ‘whole-of-house’ above-ground trial and 2 years of the in-ground trial, no termite damage has occurred to boron-treated timbers. Furthermore, we refer to analytical data by two NATA certified laboratories in Brisbane of the Tru-Core® Timber Preservation Process which was applied as a spray treatment from a mobile unit. This system is a boron-based multi-component biocide system, incorporating glycol borates, deltamethrin, permethrin and the fungicide propiconazole, that surpassed all the minimum requirements of AS 1604.1-2010 for the H2 status, even penetrating the heartwood of radiata pine and oregon. While, this standard does not specify the methods of preservative treatment that may be adopted to achieve the specified penetrations and retentions. It states that the standard is only intended for application in approved industrial treatment plants. In the current climate of extreme environmental challenges out standards need to broaden the scope of protection and treatment and also consider the new generation of biocides are different than the traditional wood preservatives. Standards specify the minimum requirements of a preservative to protect timber from attack and damage from termites and the document must encourage innovative systems for access into the industry and the protection of structural timbers.
B M Ahmed (Shiday), J R J French
TRU-CORE Process for Treatment of Refractory Species and Engineered Wood Products
2011 - IRG/WP 11-40573
The TRU-CORE Process is a novel, chemically-based technology for rapidly delivering globally accepted wood preservatives and insecticides deep into the core of wood and wood-based composites in a waterborne carrier. Protectant materials which can be utilized with the TRU-CORE Process include a variety of carbon-based fungicides and insecticides. An important feature of the TRU-CORE Process is its ability to completely penetrate wood species such as Douglas fir and SPF, which are generally considered to be refractory (very difficult to penetrate) and its ability to treat wood composites such as laminated veneer lumber (LVL) and oriented strand board (OSB) without impairing their appearance or reducing their mechanical properties. Some of the basic characteristics of the TRU-CORE Process are presented along with data demonstrating its ability to treat several commercially important but normally difficult-to-treat wood species and composites with protectant materials such as the insecticide permethrin. These building materials, once treated, can meet key standards set by the building codes in many jurisdictions.
A S Ross
Effect of silver nanoparticles on the rate of heat transfer to the core of the medium-density fiberboard mat
2014 - IRG/WP 14-40653
Effect of silver nanoparticles on the rate of heat transferred to the core section of medium-density fiberboard (MDF) mat was studied here. A 400 ppm aqueous nanosilver suspension was used at three consumption levels of 100, 150, and 200 mL/kg based on the weight of dry wood fibers; the results were then compared with the control MDF panels. The size range of silver nanoparticles was 30-80 nm. Results showed that the uniform and even dispersion of nanoparticles throughout the MDF-matrix significantly contributed to the faster transfer of heat to the core section. As to the loss of mat water content after the first 3 – 4 minutes under the hot press, the core temperature slightly decreased in the control panels. However, heat-transferring property of silver nanoparticles contributed in keeping the core temperature rather constant in the NS150 and 200 treatments. As to the de-polymerization of part of the resin in the surface layers of the mat due to the rapid absorption of heat from hot plates by the nanoparticles, it can be concluded that the optimum nano-suspension content should not necessarily be the highest one.
H Reza Taghiyari, O Schmidt, E Bari, P M Tahir, A Karimi, P Nouri, A Jahangiri
Above-ground performance of a buffered amine oxide treatment system against Mastotermes darwiniensis
2016 - IRG/WP 16-10855
Above-ground H2 field tests against Mastotermes darwiniensis were conducted in far north Queensland to assess the efficacy of buffered amine oxide treatments in the softwoods Pinus sylvestris and P. radiata, and the hardwoods Eucalyptus regnans and E. diversicolor. Untreated hardwoods and slash pine bait wood (P. elliottii) were severely attacked or destroyed, while untreated P. sylvestris was moderately to heavily attacked and untreated P. radiata only light-moderately attacked probably due to its high heartwood content. In softwoods, the H2 (permethrin) and H3 (Cu Quat) buffered amine oxide treatments were more effective than comparative H2F and H3 LOSP treatments. Nevertheless, as test blocks were cut after treatment from longer lengths, all treatments had some replicates with holes often penetrating deeply from the ends, indicating treatment breach against this most voracious of termite species. Unlike the softwood trial, hardwood test blocks were treated in final form and any damage that occurred was from the sides. All H2 buffered amine oxide treated hardwood blocks were sound, while some damage occurred in other treatments.
L J Cookson, R W Clawson Jr