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Wood in concrete. Summary of discussion at IRG 14, Surfers Paradise, Australia
1984 - IRG/WP 3264
The performance of untreated and preservative treated wood when placed in direct contact with concrete was considered in a discussion session at IRG 14. While published reports in this area are scarce, research is in progress internationally and a variety of practices are currently available to minimize any additional hazard posed by contact with concrete. This report summarizes the points raised at the IRG discussion.
R J Murphy


Life cycle analysis of utility poles. A Swiss case study
1995 - IRG/WP 95-50040-05
Use of preservative-treated wood products faces increasing public and political pressure because of environmental concerns regarding the chemicals used to protect the wood. However, critics usually focus only on one single aspect of the whole life cycle of treated wood products, disregarding other environmental effects of timber utilization. To evaluate the ecological consequences of wooden utility poles (CCF/CCB impregnated roundwood and glulams) and their alternatives of reinforced concrete and steel, a life cycle assessment was conducted. Based on data from existing Swiss electricity transmission lines, a comprehensive inventory was established of all extractions from, and emissions to the environment caused by each process step. This inventory data was linked to possible environmental impacts using various aggregation methods. An evaluation was made for single poles as well as for whole transmission lines. The results show that impregnated roundwood utility poles in fact have certain environmental benefits when considered over their whole life cycle.
T Künniger, K Richter


A review of environmental emissions from building and construction materials in comparison with preserved wood
2005 - IRG/WP 05-50224-11
A review of the public domain literature concerning emissions to the environment from materials which are used in the construction of buildings (e.g. Concrete, Asphalt, Galvanised Steel), in comparison with preserved wood, and a review of the approaches taken by the construction sector in assessing the risk from environmental emissions, in comparison with the approaches taken by the wood preservation sector.
E F Baines


Comparative life cycle assessment of Swiss railroad sleepers
1998 - IRG/WP 98-50117
The results of an environmental LCA carried out on railway sleepers made of prestressed concrete, sectional steel and creosote impregnated beech as used on main lines of Switzerland's railways are presented. All extractions from and insertions into the environment which were connected with the manufacture, use and disposal of the different types of sleeper were inventoried and assessed, in accordance with ISO 14040 guidelines. Included in the analysis were the sleepers themselves, the auxiliary materials and a part of the impacts caused by the construction work plus the maintenance of the track bed including the resulting transports. Creosote impregnated beech wood sleepers exhibit unfavourable ecological characteristics in practically all impact categories. When compared with concrete and steel sleepers, in particular the shorter servicelife but also emissions from creosote components during usage and the relatively complex rail mounting arrangement have a negative impact on their environmental profile. Several measures for an environmental improvement are discussed and investigated. It is especially important and realistic to reduce the emissions from creosote components during the servicelife of the wooden sleepers. This can be partly achieved by reducing the amount of creosote per sleeper unit. Considerably more effective is the use of creosote WEI type C instead of type B, which has a lower proportion of low boiling and therefore lower volatile components. Employing suitable optimisation measures in particular for lengthening the servicelife, would be an additional step to improve the environmental profile of the beech sleeper.
T Künniger, K Richter


The practice of using concrete on wood piling for marine use in Thailand
1982 - IRG/WP 492
The practice of using concrete on wooden poles has been carried on in Thailand for a long time in pile-houses and pier constructions which have been situated in, or partly in the sea. In such instances, the hewed round and/or square-sawn heartwood poles of naturally durable timber species have been coated with concrete of about 5 to 10 cm or more in thickness, and to about 100 cm above the highest tide level. Very durable species such as Xylia kerrii Craib & Hutch., Shorea obtusa Wall., Pentacme suavis A.DC., Hopea odorata Roxb., and Pterocarpus macrocarpus Kurz were used for such poles. They were well air-dried before the application and coated with a special mixture of concrete, which consisted of sand, crushed lime and stone, and cement powder which was used 1-2 times more than the concrete mixture used for general masonry. The performance of these poles treated in this way, as far as could be ascertained from the users, is about 15 to 20 years, or even more in some instances. Unfortunately it has not been possible to obtain exact data on the service life of these concrete-coated poles. Also palm trees have been used in sea-water without any treatment. The palm trees that have been used are Livistona saribus Herr., and Livistona speciesa Kurz. These have been used as piling for anchoring fishing boats to, because of their high elasticity and also as piles for supporting piers. They have given performances of more than 10 years of service. The outer parts of these trees are very strong and naturally durable to marine borer attack, but the inner parts of them are not resistant to decay fungi, although even though their inner parts have become rotted, they have remained strong enough for the above-mentioned purposes of utilization. If these palm trees are treated with suitable preservatives before being put into use, in order to protect them against the decay fungi, their service lives are much greater than those of untreated palms.
B Anuwongse


Prevention of Termite Tubing Over Non-Wood Construction Materials Using Glycol Borate
2004 - IRG/WP 04-30358
Glycol borates have been demonstrated to prevent termite tubing and attack of wood materials and are extensively used as termite preventative applications in new construction in the USA. This study evaluated the ability of such systems to prevent Formosan subterranean termite tubing over non-wood materials. Concrete was selected as a common inert construction material and tests were carried out following topical treatment of the concrete with a commercially available glycol borate. It was found that a glycol borate treatment on concrete restricted the ability of termites to construct tubes. Exploratory tubes were less than 20 cm and the treatment caused near complete termite mortality. The results suggest that glycol borates offer a novel approach to protect cellulosic materials within structures not built from wood.
W R Smith, J D Lloyd


Alkaline building materials and controlled moisture conditions as causes for dry rot Serpula lacrymans growing only in houses
1985 - IRG/WP 1272
Dry rot Serpula lacrymans ( Fr.) S.F. Gray is commonly found in houses, though never with certainly in nature, like other wood destroying fungi which grow both indoors and outdoors. In investigating series of dry rot instances it was shown that this fungus is always found in covered places, close to a moisture source, the distance being from 0 a maximum of 600 cm. Owing to the dry rot has been able to humidfy woodwork to the optimum condition of 20-30% wood humidity, while a lethal water content of 55% would be reached outdoors. At the same time the close presence of alkaline building materials, such as mortar, a clay layer, plaster or concrete has been observed in all instances, the average distance being from 0-100 cm. By neutralizing the dry rot fungus large production of oxalic acid the alkaline materials are able to adjust the pH to optimum levels. These two conditions are the reason why the dry rot fungus only occurs in houses.
J Bech-Andersen


Environmental consequences of various materials in utility poles - A life cycle analysis
1992 - IRG/WP 92-3726
A model for environmental life cycle analysis, LCA, has been created to compare environmental impact from transmission poles, made alternatively of concrete, steel, aluminium and pine wood treated with CCA type B or creosote. The main pollution sources and energy use are included in the LCA. One pole size, 12 meters long, is presented in the study, a so called "45 kV" pole. Poles of different materials can be divided into different groups considering different types of pollution. The use of poles made of concrete, steel and aluminium leads mainly to emission to the air, while treated wood mainly leaches preservatives during the operation and service phase. It is, by the knowledge we have today hard to compare these two types of discharge.
M Erlandsson, K Ödeen, M-L Edlund


The effect of concrete embedment on CCA treated hardwood and softwood timbers
1985 - IRG/WP 3340
Small size stakes of Eucalyptus maculata and Pinus elliottii were treated with CCA to various retentions and embedded in concrete collars containing varying amounts of a fungicide additive. During the 30 month trial period stakes were removed after 12, 18, 24 and 30 months and assessed for residual strength. Stakes which showed significant strength reductions were microscopically examined for the presence and extent of decay. The results obtained suggest that concrete collars provide a stable environment suitable for microbial activity and that the addition of a fungicide will provide protection within the concrete collar. Never-the-less decay is likely to occur outside the levels of the concrete collar especially with treated hardwoods which are recognised as being susceptible to soft rot decay.
L E Leightley, G A Willoughby


Estudio comparativo entre postes de Eucalyptus saligna Smith, Pinus caribaea Morelet (pino macho) y Hormigón
2008 - IRG/WP 08-40436
As consequence of the Energy Revolution and the amplification of the communication networks, Cuba carries out significant expenditures of foreign currencies in the import of public service posts. It is presented in this work a synthesis of the current problem in Cuba of the public service posts (PSP), since as answer to the stocks of improvement of the national Electric System, the demand of this selection has been increased notably. They are given to know the superior advantages of the eucalyptus post on that of pine and of concrete, from the technical, economic and environmental point of view. It intends the application of a methodology for the maintenance, care and conservation of the wooden posts, for the continuation of their useful life cycle as well as the forest species of more perspectives with arrangement to the recommended use. Como consecuencia de la Revolución Energética y la ampliación de las redes de comunicación, Cuba realiza significativas erogaciones de divisas en la importación de postes de servicio público. Se presenta en este trabajo una síntesis de la problemática actual en Cuba de los postes de servicio público (PSP), ya que como respuesta a las acciones de mejora del Sistema Eléctrico nacional, la demanda de este surtido se ha incrementado notablemente. Se dan a conocer las superiores ventajas del poste de eucalipto sobre el de pino y de hormigón, desde el punto de vista técnico, económico y ambiental. Se propone una metodología para el mantenimiento, cuidado y conservación de los postes de madera, para la prolongación de su ciclo de vida útil así como las especies forestales de mayores perspectivas con arreglo al uso recomendado.
C Sosa Suárez, I D Velázquez Viera, K Manzanares Ayala


Re-use of casting timber
2011 - IRG/WP 11-50283
Re-use of casting timber could be a way of saving timber resources, particularly in countries where most timber for construction purposes has to be imported. The objective of the present study was to investigate residual concrete on casting timber re-used five times. Moulds were made of sections of Norway spruce, untreated and treated with a casting oil and a wax formulation applied by a vacuum-pressure process, respectively. Casting was carried out with concrete of strength class C40/50 with a slump of 120 mm. The concrete was allowed to set for at least ten days before the sections were investigated with respect to residual concrete. None of the treatments, wax applied by vacuum pressure treatment or casting oil applied by brushing, resulted in completely residual free wood surfaces after five castings. The best result was obtained with the casting oil. If application by vacuum-pressure ever shall be an attractive alternative to the superficial treatment with casting oil, further improvements of the treatment formulation are necessary. It is hardly realistic to completely avoid residues, but re-use of the casting timber five times should be possible if the residues can be minimized and some scraping can be accepted.
I Johansson, S Breyne, H Egnell, J Jermer


Conclusions and Summary Report Environmental Life Cycle Assessment of Marine Pilings
2013 - IRG/WP 13-50298
The Treated Wood Council has completed a quantitative evaluation of the environmental impacts associated with the national production, use, and disposition of treated wood, concrete, galvanized steel, and plastic marine piles using life cycle assessment (LCA) methodologies and following ISO 14044 standards. The results for treated wood piles are significant. • Less Energy & Resource Use: Treated wood marine piles require less total energy and less fossil fuel than concrete, galvanized steel, and plastic marine piles. Treated wood marine piles require less water than concrete and plastic marine piles. • Lower Environmental Impacts: Treated wood marine piles have lower environmental impacts than concrete, steel, and plastic marine piles in all six impact indicator categories assessed: anthropogenic greenhouse gas, total greenhouse gas, acid rain, ecotoxicity, and eutrophication-causing emissions. • Decreases Greenhouse Gas Levels: Use of treated wood marine piles lowers greenhouse gas levels in the atmosphere whereas concrete, galvanized steel, and plastic marine piles increase greenhouse gas levels in the atmosphere. • Offsets Fossil Fuel Use: Reuse of treated wood marine piles for energy recovery in permitted facilities with appropriate emission controls will further reduce greenhouse gas levels in the atmosphere, while offsetting the use of fossil fuel energy. Impact indicator values were normalized to better support comparisons between products and to understand the quantitative significance of indicators. Product normalization sets the cradle-to-grave life cycle value of maximum impact to 1.0, and all other values are a fraction of 1.0. The carbon embodied in wood products, such as marine piles, is removed from the atmosphere during growth, stored for decades while the product is in use, and can be used for beneficial energy recovery at disposition. This temporary storage of carbon in the wood product reduces atmospheric levels of CO2 because the service life of the pile exceeds the time required for tree growth.
AquAeTer, Inc.


Conclusions and Summary Report on an Environmental Life Cycle Assessment of Utility Poles
2013 - IRG/WP 13-50299
The Treated Wood Council has completed a quantitative evaluation of the environmental impacts associated with the national production, use, and disposition of pentachlorophenol-treated wood, concrete, galvanized steel, and fiber-reinforced composite utility poles using life cycle assessment (LCA) methodologies and following ISO 14044 standards. The results for treated wood poles are significant. • Less Energy & Resource Use: Treated wood utility poles require less total energy, less fossil fuel, and less water than concrete, galvanized steel, and fiber-reinforced composite utility poles. • Lower Environmental Impacts: Treated wood utility poles have lower environmental impacts than concrete, steel, and fiber-reinforced composite utility poles in five of the six impact indicator categories assessed: anthropogenic greenhouse gas, total greenhouse gas, acid rain, ecotoxicity, and eutrophication-causing emissions. • Decreases Greenhouse Gas Levels: Use of treated wood utility poles lowers greenhouse gas levels in the atmosphere whereas concrete, galvanized steel, and fiber-reinforced composite utility poles increase greenhouse gas levels in the atmosphere. • Offsets Fossil Fuel Use: Improved reuse of pentachlorophenol-treated utility poles for energy recovery will further reduce greenhouse gas levels in the atmosphere, while offsetting the use of fossil fuel energy. Impact indicator values for the cradle-to-grave life cycle of pentachlorophenol-treated utility poles were normalized to one (1.0), with concrete, galvanized steel, and fiber-reinforced composite utility pole impact indicator values being a multiple of one (if larger) or a fraction of one (if smaller). The carbon embodied in wood products, such as utility poles, is removed from the atmosphere during growth, stored for decades while the product is in use, and can be used for beneficial energy recovery at disposition. This temporary storage of carbon in the wood product reduces atmospheric levels of CO2 because the service life of the pole exceeds the time required for tree growth.
AquAeTer, Inc.


Compatibility of Acetylated Wood and Wet Concrete
2014 - IRG/WP 14-40673
One of the newer commercial technologies to provide stability and durability to wood and wood composites is the process of acetylation (the reaction of acetic anhydride with wood). Wood is often used in contact with concrete, although only a very limited amount of species are suitable for this type of application because of durability issues. From this perspective durability class 1 timber such as Accoya®, is well suited to the application. The research topic in this paper relates to concern that acetylated wood may suffer a reduction in acetyl level when used in contact with concrete, due to the alkaline nature of concrete and the sensitivity of acetyl groups to alkaline conditions. Acetyl groups are known to be sensitive to pH’s greater than 7. To determine if acetylated wood can be safely used in contact with concrete without the loss of acetyl content, a series of experiments were conducted using both dry and wet samples in contact with concrete. The results show that there is no loss of acetyl when the acetylated samples were kept dry in contact with concrete and also no loss when samples were cycled for three and six months between wet and dry conditions.
R Rowell, C Lankveld, J Alexander


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


Aiming for eco-friendly log production and wooden construction!
2021 - IRG/WP 21-50365
In order to reduce greenhouse gas (GHG) emissions to zero by 2050 in the fields of forest and forest products, it is necessary to promote appropriate management and renewal of planted forests, and development of wooden building materials and the wooden construction of mid-to-high-rise buildings with lower GHG emissions. Unless we also try to reduce the environmental loads other than GHG for such development, we cannot simply replace it with other materials and construction methods. Therefore, we assessed GHG emissions up to the production of domestic logs which are the raw materials for all wood-based materials. The environmental loads of an office building made of the fireproof glulam impregnated with fire-retardant and an apartment using gypsum board-covered CLT were also assessed with those of steel-framed and reinforced concrete buildings. As a result, in log production, it is necessary to reforest after clear-cutting, and in order to give mid-to-high-rise wooden buildings the fire resistance required in Japan, gypsum board should not be used or alternatives with low environmental impact should be used.
N Hattori