Juvenile wood is not well suited for use in many forest products. Understanding factors that affect the formation of juvenile and mature wood is important when managing commercially important conifer species. The purpose of this investigation was to determine the contribution of ring age, relative height in the stem, and crown position (within or not within the green crown) on ring specific gravity of loblolly pine trees pruned at young ages. A designed experiment consisting of five treatments, control; prune at age 3 yr, age 6 yr, or age 9 yr; and at ages 3,6, and 9 yr, was established at two locations in the Piedmont region of Virginia. Wood samples were acquired at three heights along the stem 15 yr after planting. Results showed that differences in ring specific gravity of the treated plots (Half of green crown removed at each scheduled pruning) were significantly higher than that of the control plots. All variables of ring age, relative height and ring position of within or not within the green crown, were statistically significant. The results suggest that cambial age, maturation, and proximity to green crown are important for controlling whole-ring specific gravity in loblolly pine trees.
{"title":"Effects of early pruning on ring specific gravity in young loblolly pine trees","authors":"H. Burkhart, R. Amateis","doi":"10.22382/wfs-2020-013","DOIUrl":"https://doi.org/10.22382/wfs-2020-013","url":null,"abstract":"Juvenile wood is not well suited for use in many forest products. Understanding factors that affect the formation of juvenile and mature wood is important when managing commercially important conifer species. The purpose of this investigation was to determine the contribution of ring age, relative height in the stem, and crown position (within or not within the green crown) on ring specific gravity of loblolly pine trees pruned at young ages. A designed experiment consisting of five treatments, control; prune at age 3 yr, age 6 yr, or age 9 yr; and at ages 3,6, and 9 yr, was established at two locations in the Piedmont region of Virginia. Wood samples were acquired at three heights along the stem 15 yr after planting. Results showed that differences in ring specific gravity of the treated plots (Half of green crown removed at each scheduled pruning) were significantly higher than that of the control plots. All variables of ring age, relative height and ring position of within or not within the green crown, were statistically significant. The results suggest that cambial age, maturation, and proximity to green crown are important for controlling whole-ring specific gravity in loblolly pine trees.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"139-151"},"PeriodicalIF":1.4,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43590716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To evaluate the reliability of lumber structures, good models for the strength and stiffness distributions of visual and machine stress-rated (MSR) grades of lumber are necessary. Verrill and coworkers established theoretically and empirically that the strength properties of visual and MSR grades of lumber are not distributed as 2-parameter Weibulls. Instead, strength properties of grades of lumber must have “pseudo-truncated” distributions. To properly implement the pseudo-truncation theory (to correctly estimate the MOR and MOE distributions of graded subpopulations), one must know the MOE and MOR distributions of full (“mill-run”) lumber populations. Owens and coworkers investigated the mill-run distributions of MOE and MOR at each of four mills. They found that univariate mill-run MOE and MOR distributions are well-modeled by skew normal distributions or mixtures of normal distributions but not so well modeled by normal, lognormal, 2-parameter Weibull, or 3-parameter Weibull distributions. They noted that it was important to investigate whether these results were stable over time. In this article, to investigate stability over time, the authors extend the analyses of “summer” data sets performed by Owens et al to new mill-run “winter” data sets. The results show that normal, lognormal, 2-parameter Weibull and 3-parameter Weibull distributions continue to perform relatively poorly, and that skew normal distributions and mixtures of normal distributions continue to perform relatively well.
{"title":"Distributions of MOE and MOR in Eight Mill-Run Lumber Populations (Four Mills at Two Times)","authors":"F. Owens, S. Verrill, R. Shmulsky, R. Ross","doi":"10.22382/wfs-2020-015","DOIUrl":"https://doi.org/10.22382/wfs-2020-015","url":null,"abstract":"To evaluate the reliability of lumber structures, good models for the strength and stiffness distributions of visual and machine stress-rated (MSR) grades of lumber are necessary. Verrill and coworkers established theoretically and empirically that the strength properties of visual and MSR grades of lumber are not distributed as 2-parameter Weibulls. Instead, strength properties of grades of lumber must have “pseudo-truncated” distributions. To properly implement the pseudo-truncation theory (to correctly estimate the MOR and MOE distributions of graded subpopulations), one must know the MOE and MOR distributions of full (“mill-run”) lumber populations. Owens and coworkers investigated the mill-run distributions of MOE and MOR at each of four mills. They found that univariate mill-run MOE and MOR distributions are well-modeled by skew normal distributions or mixtures of normal distributions but not so well modeled by normal, lognormal, 2-parameter Weibull, or 3-parameter Weibull distributions. They noted that it was important to investigate whether these results were stable over time. In this article, to investigate stability over time, the authors extend the analyses of “summer” data sets performed by Owens et al to new mill-run “winter” data sets. The results show that normal, lognormal, 2-parameter Weibull and 3-parameter Weibull distributions continue to perform relatively poorly, and that skew normal distributions and mixtures of normal distributions continue to perform relatively well.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"165-177"},"PeriodicalIF":1.4,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47151890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The US housing construction market consumes vast amounts of resources, with most structural elements derived from wood, a renewable and sustainable resource. The same cannot be said for all nonresidential or high-rise buildings, which are primarily made of concrete and steel. As part of continuous environmental improvement processes, building life-cycle assessment (LCA) is a useful tool to compare the environmental footprint of building structures. This study is a comparative LCA of an 8360-m 2 , 12-story mixed-us apartment/office building designed for Portland, OR, and constructed from mainly mass timber. The designed mass timber building had a relatively lightweight structural frame that used 1782 m 3 of cross-laminated timber (CLT) and 557 m 3 of glue-laminated timber (glulam) and associated materials, which replaced approximately 58% of concrete and 72% of rebar that would have been use in a conventional building. Compared with a similar concrete building, the mass timber building had 18%, 1% and 47% reduction in the impact categories of global warming, ozone depletion, and eutrophication, respectively, for the A1-A5 building LCA. The use of CLT and glulam materials substantially decreased the carbon footprint of the building, although it consumed more primary energy compared with a similar concrete building. The impacts for the mass timber building were affected by large amounts of gypsum board, which accounted for 16% of the total building mass. Both lowering the amount of gypsum and keeping the mass timber production close to the construction site could lower the overall environmental footprint of the mass timber building.
{"title":"Comparative life-cycle assessment of a mass timber building and concrete alternative","authors":"Shaobo Liang, H. Gu, Richard Bergman, S. Kelley","doi":"10.22382/wfs-2020-019","DOIUrl":"https://doi.org/10.22382/wfs-2020-019","url":null,"abstract":"The US housing construction market consumes vast amounts of resources, with most structural elements derived from wood, a renewable and sustainable resource. The same cannot be said for all nonresidential or high-rise buildings, which are primarily made of concrete and steel. As part of continuous environmental improvement processes, building life-cycle assessment (LCA) is a useful tool to compare the environmental footprint of building structures. This study is a comparative LCA of an 8360-m 2 , 12-story mixed-us apartment/office building designed for Portland, OR, and constructed from mainly mass timber. The designed mass timber building had a relatively lightweight structural frame that used 1782 m 3 of cross-laminated timber (CLT) and 557 m 3 of glue-laminated timber (glulam) and associated materials, which replaced approximately 58% of concrete and 72% of rebar that would have been use in a conventional building. Compared with a similar concrete building, the mass timber building had 18%, 1% and 47% reduction in the impact categories of global warming, ozone depletion, and eutrophication, respectively, for the A1-A5 building LCA. The use of CLT and glulam materials substantially decreased the carbon footprint of the building, although it consumed more primary energy compared with a similar concrete building. The impacts for the mass timber building were affected by large amounts of gypsum board, which accounted for 16% of the total building mass. Both lowering the amount of gypsum and keeping the mass timber production close to the construction site could lower the overall environmental footprint of the mass timber building.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"217-229"},"PeriodicalIF":1.4,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42340639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Because wood has both brittle and ductile behaviors, the impact of stress concentration around notches is difficult to quantify. This research used the bending stiffness to strength ratio as a means of evaluating stress concentrations in the tension and compression faces of small clear spruce-pine-fir beams. The bending strength and stiffness behavior of wood and wood composites is of particular interest in ladder rails, laminated beams, and structural cross laminated timber, and other heavy timber construction. It was found that rectangular notches up to half of the beam depth located on the tension face reduced the bending strength by 10.5%. The drop in in ductility, as measured by MOE/MOR, was significantly higher, up to 52%. Beams loaded with the notch on the compression face had no statistically significant change in MOR; however, ductility dropped by as much as 30%.
{"title":"Ductility and Brittleness in small clear notched S-P-F beams","authors":"R. Shmulsky, L. Correa, R. Ross, B. Farber","doi":"10.22382/wfs-2020-020","DOIUrl":"https://doi.org/10.22382/wfs-2020-020","url":null,"abstract":"Because wood has both brittle and ductile behaviors, the impact of stress concentration around notches is difficult to quantify. This research used the bending stiffness to strength ratio as a means of evaluating stress concentrations in the tension and compression faces of small clear spruce-pine-fir beams. The bending strength and stiffness behavior of wood and wood composites is of particular interest in ladder rails, laminated beams, and structural cross laminated timber, and other heavy timber construction. It was found that rectangular notches up to half of the beam depth located on the tension face reduced the bending strength by 10.5%. The drop in in ductility, as measured by MOE/MOR, was significantly higher, up to 52%. Beams loaded with the notch on the compression face had no statistically significant change in MOR; however, ductility dropped by as much as 30%.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"230-236"},"PeriodicalIF":1.4,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43244845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stacks of red oak ( Quercus ru bra) and black gum ( Nyssa sylvatica ) railroad ties were seasoned 150, 200, or 300 mm above the ground to investigate the effect of height on fungal colonization and timber properties. Decay fungi became increasingly abundant as seasoning time increased. Decay fungi were more abundant on black gum than red oak ties, but fungal isolation frequency did not differ with variation in seasoning sill height. Similarly, neither MOR nor MOE differed with seasoning height. The results indicate that decreasing the tie seasoning height by 150 mm had no significant effect on either fungal colonization or timber properties.
{"title":"Effect of Distance Above Ground during Air Seasoning on Flexural Properties of Blackgum and Red Oak Ties","authors":"Leon Rogers, Jed Cappellazzi, J. Morrell","doi":"10.22382/wfs-2020-018","DOIUrl":"https://doi.org/10.22382/wfs-2020-018","url":null,"abstract":"Stacks of red oak ( Quercus ru bra) and black gum ( Nyssa sylvatica ) railroad ties were seasoned 150, 200, or 300 mm above the ground to investigate the effect of height on fungal colonization and timber properties. Decay fungi became increasingly abundant as seasoning time increased. Decay fungi were more abundant on black gum than red oak ties, but fungal isolation frequency did not differ with variation in seasoning sill height. Similarly, neither MOR nor MOE differed with seasoning height. The results indicate that decreasing the tie seasoning height by 150 mm had no significant effect on either fungal colonization or timber properties.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"208-216"},"PeriodicalIF":1.4,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42878171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The focus of this research was to investigate the bonding quality of the adhesives type after exposure to various moisture and temperature changes. This exposure was to simulate the changes in the interior application, which can cause problems in furniture manufacturing, especially with the usage of different adhesives. Different types of adhesives (Polyvinyl acetate (PVAc), Polyurethane (PUR), urea-formaldehyde (UF), and melamine-urea-formaldehyde (MUF)) were tested for bonding quality on two hardwood species; European beech ( Fagus sylvatica L.) and English oak ( Quercus robur L.). Bonding quality was tested based on EN13354 standard for control specimens, after 8 and 16 cycles of moisture and temperature changes. There was no statistical difference in bonding quality for the PVAc adhesive on beech and oak wood. PUR adhesive showed a significant decrease in the bonding quality of beech wood and no change in oak wood after exposure. The highest reduction in bonding quality after exposure cycles was found in the UF adhesive due to hydrolysis of the adhesive, regardless of the wood species. There was only reduction in the bonding quality for the MUF adhesive for beech wood after 16 cycles of the exposure condition.
{"title":"Hardwood species bonding properties after cyclic changes of environmental conditions","authors":"Tomáš Pipíška, P. Král","doi":"10.22382/wfs-2020-021","DOIUrl":"https://doi.org/10.22382/wfs-2020-021","url":null,"abstract":"The focus of this research was to investigate the bonding quality of the adhesives type after exposure to various moisture and temperature changes. This exposure was to simulate the changes in the interior application, which can cause problems in furniture manufacturing, especially with the usage of different adhesives. Different types of adhesives (Polyvinyl acetate (PVAc), Polyurethane (PUR), urea-formaldehyde (UF), and melamine-urea-formaldehyde (MUF)) were tested for bonding quality on two hardwood species; European beech ( Fagus sylvatica L.) and English oak ( Quercus robur L.). Bonding quality was tested based on EN13354 standard for control specimens, after 8 and 16 cycles of moisture and temperature changes. There was no statistical difference in bonding quality for the PVAc adhesive on beech and oak wood. PUR adhesive showed a significant decrease in the bonding quality of beech wood and no change in oak wood after exposure. The highest reduction in bonding quality after exposure cycles was found in the UF adhesive due to hydrolysis of the adhesive, regardless of the wood species. There was only reduction in the bonding quality for the MUF adhesive for beech wood after 16 cycles of the exposure condition.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"237-242"},"PeriodicalIF":1.4,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48220877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Yue, Xulei Song, Jiao Xuekai, Lu Wang, Jia Chong, Zhang-jing Chen, Weiqing Liu
In this study, to improve the structural applications of glued laminated timber (glulam) in high RH environment according to its relatively lower MOE, fast-growing poplar laminae with a thickness of 35 mm were thermally treated at 20 o C for 3.5 h. The effects of thermal treatment and RH in the surrounding environment on laminae strength class was conducted. Afterward, 12 full-scale same-grade composition glulam beams made out of untreated and thermally treated poplar laminae were prepared. The four-point bending tests were conducted to reveal the effects of laminae thermal treatment and RH in the surrounding environment on flexural properties of glulam beams with a span-depth ratio of 18. The results showed that the strength class of fast-growing poplar laminae was negatively related to RH in the surrounding condition, and thermal treatment can contribute to the increase in strength class. In 90% RH, strength class increased from untreated laminae M E 7 to the heat-treated M E 10, according to China standard. The relationship between bending properties of glulam beams and RH in the surrounding environment was negatively correlated, as well as thermal treatment, whereas MOE was improved significantly after thermally pretreated, especially in high RH. In 90% RH, MOE of glulam beams made of thermally pretreated laminae was 29.57% higher than the untreated beams with an MOR reduction of 8.82%. The results of characteristic load-deformation curves, characteristic load-strain curves, average extreme fiber strain, and the failure mode can support each other in this study. Industrial thermal treatment technology to laminae improved the MOE of glulam beams significantly in high RH with a reduction in MOR, and glulam beam made out of thermally treated fast-growing poplar laminae can be used in construction, but need checking in MOR or be used for a limited range of structural elements.
{"title":"An experimental study of flexural behavior of glulam beams made out of thermally treated fast-growing poplar laminae.","authors":"K. Yue, Xulei Song, Jiao Xuekai, Lu Wang, Jia Chong, Zhang-jing Chen, Weiqing Liu","doi":"10.22382/wfs-2020-014","DOIUrl":"https://doi.org/10.22382/wfs-2020-014","url":null,"abstract":"In this study, to improve the structural applications of glued laminated timber (glulam) in high RH environment according to its relatively lower MOE, fast-growing poplar laminae with a thickness of 35 mm were thermally treated at 20 o C for 3.5 h. The effects of thermal treatment and RH in the surrounding environment on laminae strength class was conducted. Afterward, 12 full-scale same-grade composition glulam beams made out of untreated and thermally treated poplar laminae were prepared. The four-point bending tests were conducted to reveal the effects of laminae thermal treatment and RH in the surrounding environment on flexural properties of glulam beams with a span-depth ratio of 18. The results showed that the strength class of fast-growing poplar laminae was negatively related to RH in the surrounding condition, and thermal treatment can contribute to the increase in strength class. In 90% RH, strength class increased from untreated laminae M E 7 to the heat-treated M E 10, according to China standard. The relationship between bending properties of glulam beams and RH in the surrounding environment was negatively correlated, as well as thermal treatment, whereas MOE was improved significantly after thermally pretreated, especially in high RH. In 90% RH, MOE of glulam beams made of thermally pretreated laminae was 29.57% higher than the untreated beams with an MOR reduction of 8.82%. The results of characteristic load-deformation curves, characteristic load-strain curves, average extreme fiber strain, and the failure mode can support each other in this study. Industrial thermal treatment technology to laminae improved the MOE of glulam beams significantly in high RH with a reduction in MOR, and glulam beam made out of thermally treated fast-growing poplar laminae can be used in construction, but need checking in MOR or be used for a limited range of structural elements.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"152-164"},"PeriodicalIF":1.4,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44988327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Portland, OR, was the first US city to implement a deconstruction ordinance in 2016. Although salvaged lumber can have a high demand, the market for small-sized lumber from deconstructed dwellings is near saturation. New applications for this material are required for market development, industry diversification, and increasing deconstruction practices. Mass timber products such as cross-laminated timber (CLT) could be a new market for this material, but presently there is minimal information qualifying the performance of mass timber panels made with salvaged lumber. Three, full-sized 3-ply experimental layups, with varying amounts of salvaged/recycled wood content, were manufactured and tested to characterize panel properties. Manufacturing processes and testing methods followed ANSI/APA PRG 320-2018; Standard for Performance Rated Cross-Laminated Timber. Each panel layup had three replicates for nine panels in total. Panels measured 1.1 m by 2.3 m by 3 plys, and test results were used to calculate the effective flatwise bending moment resistance (( F b S ) eff ), effective flatwise bending stiffness ((EI) eff ) effective shear stiffness in flatwise bending ((GA) eff ), flatwise shear resistance (V s ), percent wood failure (WF%), and percent delamination (Delamination %). Results were compared with E3 grade 3-ply CLT panels made in the United States and indicated that salvaged lumber could be used as feedstock for mass timber panels in core layers or all layers. All panel layups passed benchmarks for ( F b S ) eff and (EI) eff benchmarks with values greater than PRG320. Panels having salvaged lumber in core layer also met V s benchmarks. Furthermore, all panels passed examination for WF% but struggled to meet delamination requirements. Possibilities exist for better performance if panels were made in a commercial setting. This research shows salvaged lumber has promise for manufacturing structural CLT, but more research and a larger samples size is needed to verify findings.
俄勒冈州波特兰是2016年第一个实施解构条例的美国城市。虽然回收木材有很高的需求，但从解构住宅中提取的小型木材的市场已经接近饱和。这种材料的新应用是市场发展、行业多样化和越来越多的解构实践所需要的。大量木材产品，如交叉层压木材(CLT)可能是这种材料的新市场，但目前很少有资料证明用回收木材制成的大量木材板的性能。三种全尺寸的三层实验铺层，具有不同数量的回收/回收木材含量，制造和测试了面板特性。制造工艺和测试方法遵循ANSI/APA PRG 320-2018;性能等级交叉层压木材标准。每个面板铺设有3个重复，共9个面板。面板尺寸为1.1 m × 2.3 m × 3层，测试结果用于计算有效的平面弯矩阻力((F b S) eff)、有效的平面弯曲刚度((EI) eff)、有效的平面弯曲剪切刚度((GA) eff)、平面剪切阻力(V S)、木材破坏百分比(WF%)和分层百分比(delamination %)。结果与美国E3级三层CLT板进行了比较，表明回收木材可作为芯层或全层厚木板的原料。所有面板层叠都通过了大于PRG320的(F b S) eff和(EI) eff基准测试。在芯层中回收木材的面板也达到了V的基准。此外，所有面板都通过了WF%的检查，但难以满足分层要求。如果在商业环境中制造面板，则有可能获得更好的性能。这项研究表明，回收木材有希望制造结构CLT，但需要更多的研究和更大的样本量来验证研究结果。
{"title":"Salvaged lumber for structural mass timber panels: manufacturing and testing","authors":"R. Arbelaez, L. Schimleck, Arijit Sinha","doi":"10.22382/wfs-2020-016","DOIUrl":"https://doi.org/10.22382/wfs-2020-016","url":null,"abstract":"Portland, OR, was the first US city to implement a deconstruction ordinance in 2016. Although salvaged lumber can have a high demand, the market for small-sized lumber from deconstructed dwellings is near saturation. New applications for this material are required for market development, industry diversification, and increasing deconstruction practices. Mass timber products such as cross-laminated timber (CLT) could be a new market for this material, but presently there is minimal information qualifying the performance of mass timber panels made with salvaged lumber. Three, full-sized 3-ply experimental layups, with varying amounts of salvaged/recycled wood content, were manufactured and tested to characterize panel properties. Manufacturing processes and testing methods followed ANSI/APA PRG 320-2018; Standard for Performance Rated Cross-Laminated Timber. Each panel layup had three replicates for nine panels in total. Panels measured 1.1 m by 2.3 m by 3 plys, and test results were used to calculate the effective flatwise bending moment resistance (( F b S ) eff ), effective flatwise bending stiffness ((EI) eff ) effective shear stiffness in flatwise bending ((GA) eff ), flatwise shear resistance (V s ), percent wood failure (WF%), and percent delamination (Delamination %). Results were compared with E3 grade 3-ply CLT panels made in the United States and indicated that salvaged lumber could be used as feedstock for mass timber panels in core layers or all layers. All panel layups passed benchmarks for ( F b S ) eff and (EI) eff benchmarks with values greater than PRG320. Panels having salvaged lumber in core layer also met V s benchmarks. Furthermore, all panels passed examination for WF% but struggled to meet delamination requirements. Possibilities exist for better performance if panels were made in a commercial setting. This research shows salvaged lumber has promise for manufacturing structural CLT, but more research and a larger samples size is needed to verify findings.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"178-190"},"PeriodicalIF":1.4,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68377274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sina Heshmati, Lukie H. Leung, M. Mazloomi, Joseph Doh Wook Kim, P. Evans
Machining grooves into the upper surface of wooden deckboards reduces undesirable checking that develops when deckboards are exposed to weather. But profiled boards cup more than unprofiled boards. We sought a solution to this problem and hypothesized that profiling both sides of boards would reduce the cupping of profiled boards. We tested the effects of profile type (Flat, single-, and double-sided profiles) and growth ring orientation (concave vs convex) on the cupping and checking of alkaline copper quaternary-treated deckboards made from Douglas fir, western hemlock, and white spruce. There were significant differences in the cupping of deckboards made from the three different wood species (Douglas fir
{"title":"A Note of the Positive Effects of Double-Sided Profiling on the Cupping and Checking of ACQ-Treated Douglas Fir, Western Hemlock and White Spruce Deckboards Exposed to Natural Weathering","authors":"Sina Heshmati, Lukie H. Leung, M. Mazloomi, Joseph Doh Wook Kim, P. Evans","doi":"10.22382/wfs-2020-022","DOIUrl":"https://doi.org/10.22382/wfs-2020-022","url":null,"abstract":"Machining grooves into the upper surface of wooden deckboards reduces undesirable checking that develops when deckboards are exposed to weather. But profiled boards cup more than unprofiled boards. We sought a solution to this problem and hypothesized that profiling both sides of boards would reduce the cupping of profiled boards. We tested the effects of profile type (Flat, single-, and double-sided profiles) and growth ring orientation (concave vs convex) on the cupping and checking of alkaline copper quaternary-treated deckboards made from Douglas fir, western hemlock, and white spruce. There were significant differences in the cupping of deckboards made from the three different wood species (Douglas fir<white spruce<western hemlock), and boards with concave growth ring orientations cupped significantly less than boards with convex growth ring orientations. Most importantly, our results show that double-sided profiling reduces the cupping of deckboards, irrespective of wood species, and growth ring orientations of deckboards. Double-sided profiling also significantly reduced checking of deckboards exposed to the weather. We conclude that profiling the underside or profiled deckboards to create a “balance” double-sided board is a simple solution to the problem of increased cupping that develops when profiled (single-sided) softwood deckboards are exposed to weather.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"243-253"},"PeriodicalIF":1.4,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48700996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Smith, S. Shi, Jiang-tao Shi, Cuicui Wang, Yulin Tan, Zhou Haiying
In this study, the effect of wood species on pore structure of activated carbon (AC) generated from a self-activation process at different dwelling times was investigated. Ten hardwood species were selected (afromosia, alder, black cherry, makore, pomelle sapele, soft maple, teak, walnut, white oak and yellow poplar) were activated at 1050 O C for three dwelling times (10 h, 5 h, and 2.5 h). X-ray diffraction, Raman spectroscopy, and elemental analysis were performed on AC to analyze the carbon structure. The Brunauer-Emmett-Teller (BET) surface area, Barrett-Joyner-Halenda (BJH) pore volume, and BJH pore width of AC samples were determined. It was shown from the study that the mesopore width of AC decreased as micropores were transitioned to mesopores, leading to an increase in the pore volume and surface area. The density and porosity of the samples that underwent 2.5-h dwelling time were determined. The porosity of the wood and their resultant AC were compared. The porosity between the wood and its AC possessed a relationship when true bulk densities of the wood and carbon were compared. The porosity of wood had an impact on the bulk density of the carbon but not on the true density. No relationship was observed between the porosity and surface area of the carbon samples.
{"title":"Effect of Wood Species on the Pore Volume and Surface Area of Activated Carbon Derived from the Self Activation Process","authors":"L. Smith, S. Shi, Jiang-tao Shi, Cuicui Wang, Yulin Tan, Zhou Haiying","doi":"10.22382/wfs-2020-017","DOIUrl":"https://doi.org/10.22382/wfs-2020-017","url":null,"abstract":"In this study, the effect of wood species on pore structure of activated carbon (AC) generated from a self-activation process at different dwelling times was investigated. Ten hardwood species were selected (afromosia, alder, black cherry, makore, pomelle sapele, soft maple, teak, walnut, white oak and yellow poplar) were activated at 1050 O C for three dwelling times (10 h, 5 h, and 2.5 h). X-ray diffraction, Raman spectroscopy, and elemental analysis were performed on AC to analyze the carbon structure. The Brunauer-Emmett-Teller (BET) surface area, Barrett-Joyner-Halenda (BJH) pore volume, and BJH pore width of AC samples were determined. It was shown from the study that the mesopore width of AC decreased as micropores were transitioned to mesopores, leading to an increase in the pore volume and surface area. The density and porosity of the samples that underwent 2.5-h dwelling time were determined. The porosity of the wood and their resultant AC were compared. The porosity between the wood and its AC possessed a relationship when true bulk densities of the wood and carbon were compared. The porosity of wood had an impact on the bulk density of the carbon but not on the true density. No relationship was observed between the porosity and surface area of the carbon samples.","PeriodicalId":23620,"journal":{"name":"Wood and Fiber Science","volume":"52 1","pages":"191-207"},"PeriodicalIF":1.4,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46363795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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