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Cross-laminated timber (CLT) is an increasingly popular wood-based alternative for large building applications. CLT panels are typically not treated due in part to a perceived lack of efficient and effective methods for treating large panels and a lack of information on what effect treatment processes may have on the panels' mechanical properties. We propose that treating CLT panels with borate solution, applied under vacuum in flexible bags, could provide a practical and effective option for providing preservative protection for interior applications. Samples were cut from commercially produced CLT panels and treated with borate solution using vacuum. The samples were then evaluated for preservative retention, swelling, and degradation of mechanical properties. Initial treatments resulted in a wide range of preservative retentions and property effects among the products tested. In subsequent adjustments, the treatment parameters were changed to provide consistent and sufficient retention among the products. The vacuum treatment method effectively penetrated cracks in the lumber and the bond lines (adhesive joint between adjacent lamellae). Swelling and effects on mechanical properties were minimal in the adjusted samples. In addition to these samples that were treated in a rigid pressure vessel, a larger sample was successfully treated in a flexible plastic bag. Data from this study support the concept that vacuum treatment of CLT panels with borate can provide sufficient levels of preservative retention, can be adjusted to the material being treated, and has minimal effects on mechanical properties., Cross-laminated timber (CLT) is emerging as an environmentally friendly alternative to concrete and steel in large buildings. CLT is among the mass timber family of products (with glulam, large timbers, [...]

Creosote, a coal tar distillate product, has been used to preserve wooden utility poles for well over 100 years. Such use began in the late 1800s and continues to this day. Creosote's efficacy in protecting wood from decay, termite attach, and general weathering has been demonstrated by actual performance of poles in utility service and in documented field and laboratory testing. The American Wood Protection Association has standardized and long recognized the efficacy of creosote preservation. With production of pentachlorophenol ending after 2022, preservation may easily convert to creosote preservative. Creosote preservative also is an environmentally sound choice in that used poles can be used as fuel and otherwise, creosote degrades biologically. Wood is sustainable as new trees are grown to replace poles while the poles are sequestered carbon. Utility service life of creosote preserved wooden poles typically lasts for 70 to over 100 years with inspection and maintenance. Utilities can expect new creosote preserved poles to last into the next century., Background Coal tar distillate (of which creosote is a product) is a dark brown liquid that is produced by thermal distillation of coal tar. Coal tar is a biproduct of [...]

Korean wood preservation standards require deep penetration, which precludes the use of many refractory species. However, such treatments of refractory species have been shown to be effective in other parts of the world. A field test was therefore initiated to evaluate the performance of western hemlock, a moderately refractory species, and white spruce, a highly refractory species, pressure treated with either copper azole or alkaline copper quaternary under Korean field conditions that included both decay and termite hazards. After 10 years of exposure in a ground proximity and field stake test in Jinju, Korea, the treated materials remained largely sound, while untreated controls failed much earlier, largely due to termite attack. These data suggest that material that does not meet current Korean penetration requirements could still provide effective protection against biodegradation under Korean conditions. Decay was more advanced in matched treated stakes exposed at a test site in Canada than at the site in Korea., The efficacy of wood preservatives is typically assessed on through-treated materials so that the impact of the preservative on decay resistance can be precisely determined. This includes laboratory tests as [...]

The effect of pretreatment with either boron or glycerol followed by thermal modification on the durability of Douglas-fir heartwood was evaluated in an American Wood Protection Association ground proximity test in Hilo, Hawaii. Non-thermally modified samples were generally more heavily decayed than any of the modified woods, but there was no consistent effect of different thermal modification conditions on decay resistance. Thermally modified woods tended to perform better than untreated timbers but not as well as copper azole-treated Douglas-fir heartwood lumber in test at the same site. The results are discussed in relation to how the extreme site conditions might have made it difficult for thermally modified materials to perform., Thernial modification is a long-established method for altering the resistance of timber to moisture uptake, thereby resulting in conditions that are presumably less conducive to fungal attack (Esteves and Pereira [...]

Seventy-five years of research in wood protection at the Forest Products Lab at Mississippi State University are described. A history of wood protection is presented along with an overview of the facilities supporting the research. Program objectives are presented along with the personnel responsible for building the program. A brief presentation of research areas is given followed by some program metrics., At is a pleasure for me to be a part of the first virtual International Convention of the Forest Products Society (nee Forest Products Research Society) and to share with [...]

The performance of several wood surface treatments as well as a silica treatment claiming to provide protection against fungal decay and termite attack in aboveground applications were examined in termite, ground proximity, and sandwich tests at a subtropical site near Hilo, Hawaii. In general, the surface treatments performed similarly to untreated controls and provided little or no protection against fungal or insect attack. The silicate treatment provided some termite and decay protection, but fungal decay resulted in rapid declines in condition after 50 to 54 months of exposure. Copper azole--treated lumber provided the best performance against both termites and fungal attack, illustrating the benefits of pressure treatment over surface treatments in highdecay-hazard environments. These results also illustrate the importance of rigorous testing and standardization protocols for any product that makes durability claims before it enters the market to ensure that it will perform as expected., Wood exposed aboveground in exterior applications is invariably subjected to wetting that creates conditions conducive to fungal attack. Extending the useful life of timber requires either using naturally durable heartwood [...]

The effect of alkaline copper quaternary type D (ACQ-D) treatment on color retention, mold resistance, and surface physicochemical characterization of Neosinocalamus afinis bamboo was analyzed. The results showed that a treatment of 0.25 percent ACQ-D solution combined with pretreatment of potassium hydroxide and sodium dodecyl sulfate mixed aqueous solution can achieve a desired green color on the bamboo surface. The mold test result revealed that the treated bamboo samples had better mold resistance than samples only treated with a mold inhibitor. The thermogravimetric--Fouriertransform infrared spectroscopy analysis of the treated and the control samples indicated that the chemical structure of the surface was slightly modified, e.g., silicon was almost completely removed, which enhanced liquid permeability. The dilute ACQ-D solution combined with a proper pretreatment process could retain the favorable green color of bamboo and also improve mold resistance by slightly modifying the surface chemistry., Nosinocalamus affinis grows widely in southwest China (Cattaneo et al. 2005), especially in Sichuan Province (the geographical distribution, cultivation, and utilization center of N. affinis; Wang et al. 2009), where [...]

Encapsulation of cellulose with wax and surfactant is a physical way to restrict cellulose-to-cellulose attraction. Because wax is often used in the wood composite process, industrial manufacturers would not have to upgrade or add expensive equipment to handle cellulose addition. The encapsulated cellulose particles could easily be transported to composite and polymer facilities and blended in a homogeneous fashion for a multitude of products and composites. It was the objective of this study to utilize differential interference contrast (DIC) microscopy to characterize the wax and surfactant coverage and encapsulation morphology of the wax--surfactant--cellulose composite. The lengths and widths of the cellulose particles were significantly changed after encapsulation. DIC microscopy found that we could fine-tune wax coverage to control homogeneity and reduce fiber bundling during dispersion. It was found that surfactants were not necessary to enhance coverage if a 1:4 ratio of wax to microcrystalline cellulose was used. However, if more wax is desired, then surfactants may be necessary to suppress fiber bundles during dispersion., Cellulose-based materials are becoming more of a value-added commodity and can be extracted from any plant material across the globe. Unlike lignin, cellulose is consistent within and between plant tissue [...]

Copper remains one of the key biocides for protecting timber in soil contact. Historically, copper-based preservatives relied on solubilized copper. Over the past decade, micronized copper systems have largely replaced soluble copper systems in this application. While micronized copper chemistries have been shown to perform well over time with reduced copper leaching compared to solubilized copper, data are lacking on the effects of repeated leaching cycles on resistance of the timber to fungal attack. The potential effects of repeated leaching cycles of micronized copper azole--treated southern pine (Pinus spp.) blocks on both copper losses and resistance to fungal attack were explored over 20 leaching cycles using Gloeophyllum trabeum and Rhodonia placenta as test fungi. Copper losses during leaching were elevated for the first two cycles and steadily declined with additional cycling. There were no noticeable differences in fungal-associated weight losses in blocks exposed to G. trabeum. There was only a slight increase in average block weight losses with R. placenta, although blocks exposed to this fungus experienced higher weight losses with increased leaching cycles. The results suggest that repeated leaching exposures may produce some localized increases in susceptibility to fungal attack, but the overall effects were minor., Chopper remains among the most widely used components for wood preservatives employed in ground contact. Copper reacts slightly with the wood and has broad spectrum activity against fungi and insects [...]

An approach for implementing statistical process control and other statistical methods as a cost-savings measure in the treated-wood industries is outlined. The purpose of the study is to use industry data to improve understanding of the application of continuous improvement methods. Variation in wood treatment is a cost when higher-than-necessary chemical retention targets are required to meet specifications. The data for this study were obtained in confidence from the American Lumber Standard Committee and were paired, normalized assay retentions for charges inspected by both the treating facility and auditing agencies. Capability analyses were developed from this data for three use categories established by the American Wood Protection Association (AWPA), including UC3B (above ground, exterior), UC4A (ground contact, freshwater, general use), and UC4B (ground contact, freshwater, critical structures, or high decay hazard zones). Agency and industry data indicate that between 4.45 and 9.82 percent of the charges were below the lower confidence limit of the passing standard (LC[L.sub.AWPA]), depending on use category. A Taguchi loss function (TLF), which is quadratic based and decomposes the monetary loss into shift and variation components, was developed to estimate the additional cost due to process variation. For example, if a treatment input cost of $1.00/[ft.sup.3] is assumed for LOB, reducing the variation in total retention allows lowering treatment targets, e.g., 1.45 to 1.38, reducing costs to $0.76/[ft.sup.3]. The study provides some important continuous improvement tools for this industry such as control charts, [C.sub.pk], [C.sub.pm] capability indices, and the one-sided TLF., Currently, wood treatment facilities must meet minimum passing standards for wood preservative penetration and retention of treated wood (as defined by the American Wood Protection Association [AWPA] and governed by [...]

The organic material of wood treated with inorganic nanoparticles has gained significant improvements in its stability against ultraviolet (UV) light and moisture degradation. Here, a new method was proposed to modify Chinese fir (Cunninghamia lancellata), which was treated by high-temperature steam and coated with titanium dioxide (Ti[O.sub.2]) nanoparticles. Due to the synergistic effect, the treated Chinese fir can obtain the properties of surface hydrophobicity and photoaging resistance that can prevent the invasion of moisture and the damage of UV light from sunlight. Scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction were used to characterize the morphology, structure, chemical composition, hydrophobicity, and light-aging resistance of the treated Chinese fir. By means of comparative experiments, the Chinese fir was treated with 5 percent nano-Ti[O.sub.2] solution and annealed at 300[degrees]C. The surface water contact angle reached to about 130[degrees], indicating the strong hydrophobicity. In addition, the total color difference ([DELTA]E*) after accelerated light aging for 120 hours was only 45 percent of the control sample., Wood, as a green environmental protection material, has many excellent characteristics including light weight (Corinaldesi et al. 2016), high ratio of strength to weight (Hoque et al. 2014), good elasticity, [...]

Thermo-hydro-mechanical (THM) treatments can be used to improve certain properties of underutilized wood species, especially those with low densities. These treatments densify the wood by softening the cell walls using heat, pressure, and moisture but are subject to set-recovery (recovery of compressive deformation) when exposed to humidity. Phenol-based resins have been successful in mitigating this issue when impregnated into the wood. This work explores the use of a new phenol-based resin combined with a THM treatment to limit set-recovery and produce products with the potential for flooring applications. Scratch resistance, hardness, and glue-line shear strength were used to assess the performance. The THM treatment and impregnated phenol resin used in this study increased the scratch resistance, density, and hardness of natural poplar wood and created satisfactory bonding conditions for flooring purposes. With optimization of THM parameters and resin solids content, the resulting product could provide a high-quality flooring material used alone or as a thin laminate from a low-density species like poplar., European policymakers and research funding in Europe have recently been pushing for reducing the dependency of European countries on imports of raw materials (e.g., proteins, energy, wood, etc.). Part of [...]

The effect of test-block grain orientation on laboratory termite tests using American Wood-Preservers' Association Standard El-97 was evaluated using Coptotermes formosanus. This research revealed that testing of samples with the 6-mm direction in either the longitudinal or the tangential direction was appropriate. The El standard was subsequently modified to allow either., Many variables play a role in the outcome or accuracy of laboratory termite test results. This contribution is the second in a multipart research program to evaluate the variables in [...]

Abstract Surface coatings of melamine-modified urea-formaldehyde resins (MUFs) containing ammonium polyphosphate (APP) have been shown to significantly improve the fire retardancy of wood by prolonging the ignition time and reducing [...]

Abstract Lateral shear resistance capacities of face-to-face single-staple and one-row vertically aligned multistaple joints in three oriented strandboards (OSB) were investigated and compared. Experimental results from testing single-staple joints indicated [...]

Abstract This research examined oil from the neem tree (Azadirachta indica A. Juss.) for its potential as an eco-friendly wood preservative. In contrast to expectations from the literature, according to [...]

Abstract Quaternary ammonium tetraphenylborates (TPBs) and quaternary ammonium tetrafluoroborates were synthesized for the manufacture of leaching-resistant boron wood preservatives. The leachability of these boron compounds and the termite and decay [...]

Introduction to the Past Since 1910, the Forest Products Laboratory (FPL) has promoted healthy forests and forest-based economies through the efficient, sustainable use of American wood resources. These past 100 [...]

Abstract Moisture gradient in wood and wood composites is one of most important factors that affects both physical stability and mechanical performance. This paper describes a method for measuring moisture [...]

Abstract In this study, the determination of the burning characteristics of oriented strandboard (OSB) and the effect on the burning characteristics of OSB when three chemical substances, potassium carbonate, borax [...]

Abstract Nonwoven fiberglass face laminates have long been applied to consolidated wood-based composites to improve their performance and serviceability. In this study, fiberglass mats with 50 percent resin binder were [...]

Abstract The dimensional stability of wood and its resistance to decay and fire can be improved by depositing inorganic materials in the wood matrix and forming wood-inorganic composites. In this [...]

Abstract Creosote has a long history of successful use as a wood preservative, but polycyclic aromatic hydrocarbons in this preservative have raised environmental concerns, particularly when creosote-treated wood is used [...]

Abstract This paper provides results of a laboratory and field test study that evaluated the termite resistance of furfurylated wood. Sapwood test specimens of three wood species were furfurylated to [...]

Protecting wood in park settings from rot and insects has been a challenge for park managers since public parks were created. Chromated copper arsenate, commonly known as CCA, replaced other [...]

Abstract The thresholds of boron and fluoride against selected decay fungi (Postia placenta, Gloeophyllum trabeum, and Trametes versicolor) were determined in Douglas-fir sapwood and heartwood in non-soil contact exposures. Even [...]

Abstract Naturally durable heartwood products have smaller dimensional changes and are an environmentally friendly alternative to the use of preservatives. The present study explored the potential for the production of [...]

Abstract The ability to treat Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) with oilborne copper-8-quinolinolate or with waterborne chromated copper arsenate, ammoniacal copper zinc arsenate, or ammoniacal copper [...]

Abstract A commercialization history of veneer-based (Impreg and Compreg) wood polymer composites (WPC) and lumber-based radiation-cured and heat-catalyst-cured WPCs is given. The case-study approach used focuses on companies with which [...]

Abstract Chromated copper arsenate (CCA) treated wood has been most widely used in North America since the 1970s for many exterior applications such as decks, fences, playground equipment, utility poles, [...]

Abstract The incidence of treated wood in a recycling stream was assessed at a recycling center in western Oregon. Chromated copper arsenate (CCA) was the predominant treatment present in the [...]

Abstract Southern yellow pine sapwood stakes and blocks were treated with the sodium salt of the calcium-precipitating compound N'N-hydroxynapthalimide (NHA) and leach tested for 2 weeks using the American Wood-Preservers' [...]

Abstract The effect of drying conditions on gas permeability and preservative treatability was assessed on western hemlock lumber. Although there were no differences in gas permeability between lumber dried at [...]

Abstract In 1998, the Building Standard Law of Japan was revised to emphasize performance-based regulations rather than conventional conformity to specifications. The method of evaluating fire-retardant material was also changed [...]

Abstract The quality and uniformity of kiln-drying is strongly influenced by the airflow distribution inside the kiln and by the moisture and heat transport inside the wood. A new comprehensive [...]

Abstract To determine the natural weathering resistance of different paint formulations, paint manufacturers coat thin, flat specimens of homogeneous substrate with their products. The essentially two-dimensional specimens are attached to [...]

Abstract A weather-protected aboveground field test was established at Kincardine, Ontario, Canada, to assess the performance against termites of two formulations of carbon-based preservative in Pacific silver fir (Abies amabilis) [...]

Copper-naphthenate-treated poles in service were inspected for deterioration, penetration, retention, and serviceability. The study included poles in all hazard zones in the United States. Poles installed by 12 different utilities [...]

Yaguang Zhou (*) D. Pascal Kamdem (*) ABSTRACT There is growing concern about the environmental risks and difficulty indisposing of preservative-treated wood products. Landfill disposal is becoming less acceptable and [...]

INTRODUCTION With the development of a water-dispersible polyisocyanate (WDP) technology in conjunction with hydroxy-functional acrylic resin, it is now possible to formulate a wood coating system with ultra low volatile [...]

My first attempt at building furniture was not an auspicious one. I was young and poor, but handy with tools, and rather than buy a kitchen table, I decided to […]

Everyone who has ever owned a spanking new cedar deck remembers how quickly the bright honey color of the freshly sawn wood began to fade, darken and turn gray. The […]