Impacts of impregnation with Imersol-Aqua on the compression strength of some solid wood materials

The aim of this study was to investigate the effects of impregnation with Imersol-Aqua on the compression strength of some solid wood materials. For this aim, Oriental beech (Fagus orientalis Lipsky), European oak (Quercus petrea Liebl.), Scotch pine (Pinus sylvestris Lipsky), Uludag fir (Abies Bornmülleriana Mattf.), Oriental spruce (Picea orientalis Lipsky) and Lombardy poplar (Populus nigra Lipsky) wood samples were prepared according to TS 2595 and impregnated with Imersol-Aqua, commonly being used in construction wood materials by the method of short, medium and long-term of dipping according to ASTM D 1413 and producers’ definition. After the impregnation process, compression strength was measured according to TS 2595. Consequently, among the non-impregnated wood materials, the highest compression strength was obtained in beech and pine samples. Compression strength at this situation from the highest to lowest can be enumerated beech, pine, oak, spruce, fir and poplar. With regard to the impregnation period, the sequence form the highest to lowest was as long-term, medium-term and short-term dipping. In the interaction of wood material and impregnation period, the highest compression strength values were obtained in Scotch pine (71.220 N mm⁻²) impregnated with long-term dipping method whereas the lowest in Lombardy poplar (35.710 N mm⁻²) impregnated with short-term dipping method.

In consequence, in the massive constructions and furniture elements that the compression strength after the impregnation is of great concern, long-term impregnation of solid wood material could be recommended.     

Effects of impregnation with Imersol-aqua on the modulus of elasticity in bending of laminated wood materials

The aim of this study was to investigate the impacts of impregnation with Imersol-aqua on the modulus of elasticity in bending (MOE) of some laminated wood materials. For this aim, oriental beech (Fagus orientalis Lipsky), oak (Quercus petrea Liebl.), Scotch pine (Pinus sylvestris Lipsky), oriental spruce (Picea orientalis Lipsky) and Uludağ fir (Abies bornmülleriana Lipsky) wood materials impregnated with Imersol-aqua according to ASTM D 1413-99 and producers’ definition. Laminated wood samples were produced from impregnated wood materials according to TS EN 386 in the five ply form (4 mm each) from oriental beech, oak, Scotch pine, Uludağ fir and oriental spruce wood by using Desmodur-VTKA adhesive. The MOE values were measured according to TS EN 408. Consequently, the MOE of impregnated + laminated (I + L_W) softwoods, pine, spruce and fir increased, respectively by 8.07%, 2.62% and 2.45% whereas the MOE of laminated + laminated hardwoods, beech and oak decreased, respectively by 5.06% and 4.37% with respect to laminated control samples (L_W). Considering the interaction of wood type and process, the MOE was obtained from laminated oriental beech, whereas the lowest was found for impregnated Uludağ fir. In consequence, in the massive construction and furniture elements that the MOE after the impregnation and lamination (I + L_W) is of great concern, oriental beech and Scotch pine materials could be recommended.     

Technological and economic comparison of the usage of beech and alder wood in plywood and laminated veneer lumber manufacturing

In this study, the economic and technological benefits of the usage of alder wood instead of beech wood as a raw material in plywood and laminated veneer lumber (LVL) manufacturing were compared, besides the conservation of national forest resources. For this aim, some technological properties of plywood and LVL panels manufactured from beech and alder logs were determined, and then compared with the values indicated in related standards. According to the results of this study, mechanical strength values of beech plywood and LVL panels were higher than those of alder panels. Bending strength mean values of plywood panels were higher than the limit values indicated in DIN 68705-3 and DIN 68792. Shear strength mean values obtained for the plywood panels manufactured from alder logs were above the limit value (1.0 N/mm²) indicated in EN 314-2 standard. Mechanical strength values of beech LVL panels were also higher than those of alder LVL panels. When the annual increments of beech and alder trees in 1 ha and the time they need to reach suitable diameters for the manufacturing rotary cut veneers were taken into consideration, it was calculated that alder trees allow 3.82 times additional physical harvesting than beech trees.     

Random field stiffness properties and reliability of laminated wood beams

This paper discusses a representation of the within-specimen variability in modulus of elasticity E for wood, utilising stationary random processes. These are used in the reliability study of a laminated wood beam for the serviceability limit state of maximum deflection. The reliability of the beam is also considered with different mechanical models: simple ones using ordinary beam theory and a more elaborate one based on a stochastic finite element formulation. Results compare the different mechanical models and, for the finite element approach, the effect that fluctuations in E within each lamination have on the beam reliability.     

典型包装材料燃烧性能的实验研究

使用锥形量热仪对典型包装材料——内衬聚苯乙烯(PS)泡沫塑料和外包装硬纸板的燃烧性能进行了实验研究,测得了不同热辐射强度下包装材料样品的燃烧性能参数。实验结果表明,包装材料受热辐射时很容易被点燃,燃烧时放出大量的热和有毒烟气。     

废弃木质碎料应用于道路铺装材料的力学性能研究

为充分利用废弃木材,探究新型道路铺装材料,研究养护龄期对不同配合比的水泥基木质碎料道路铺装材料抗压强度的影响。对试件的力学性能进行测试和分析,结果表明:各配合比下试件的抗压强度随养护龄期的增长普遍呈上升趋势且试件具有早强现象,同时发现木质碎料的比例对试件强度随养护龄期变化起到决定性作用。该实验可为废弃木质碎料应用于新型道路铺装材料的进一步研究提供参考。     

Influence of fire retardants on smoke generation from wood and wood derived materials

The influence of three fire retardant agents: Polichron, Pyrolak W-10, and Pyrolak W-10 + Pyrolak W-1 on smoke density of pine wood, plywood, soft hardboard and tough hardboard was investigated. Surface samples of 25 cm² (5 × 5 cm) were used and the heat flux was varied over the range of 1.0 to 4.0 W/cm². Reference: Tadeusz Cisek and Jacek Piechocki, Influence of Fire Retardants on Smoke Generation from Wood and Wood Derived Materials,Fire Technology, Vol. 21, No. 2, May 1985, p. 122.     

高强混凝土的应用研究

高强混凝土己在很多工程中推广应用,高性能混凝土不仅满足了建筑物结构、施工与使用功能的需要,而且还取得了可观的技术经济效益,具有很强的实用意义。本文讨论了高强混凝土配制的主要技术途径和高强混凝土的部分性能,并通过优化配比实验制成高强混凝土,并用混凝土制作了检查井盖,通过井盖的受力性能了解了低水胶比高强混凝土的抗压性能。     

Effect of bituminous impregnation on nonwoven geotextiles tensile and permeability properties

Geosynthetics interlayer systems are effective techniques to control reflective cracking in damaged pavements. It comprises the inclusion of nonwoven geotextiles between the damaged layer and the new overlay of the pavement to reduce the propagation of cracks and to extend pavement life. However, the success of this technique depends directly on the understanding of the geotextile's behavior when impregnated with asphalt. This paper evaluates different nonwoven geotextiles frequently used in anti-reflective cracking systems, focusing on initial stiffness gain and permeability reduction after asphalt impregnation. Fresh and impregnated samples of polyester and polypropylene nonwoven geotextiles were tested. Cationic rapid setting emulsified asphalt was used as asphalt binder. Wide-width tensile tests were carried out based on the specification of ABNT - NBR 12824 (1993). Water vapor transmission tests were conducted according to ASTM E 96M (2005). Results of tensile tests on impregnated geotextiles showed a significant increase on tensile strength values, probably due to the inter contact of the fibers. Results also showed high increase in strength values at strain levels less than 0.05% and decrease on stiffness gains with increase of strains. Water vapor transmission tests demonstrated that cationic asphalt emulsion applied on nonwoven geotextiles allows a drastic reduction in permeability values to turn nonwoven geotextiles into a low permeability barrier.     

木材和高聚物燃烧性能的锥形量热仪研究

利用锥形量热仪研究了木材和高聚物材料的燃烧性能,并讨论了木材和高聚物的阻燃问题.     

常用建筑材料的燃烧热值浅析

本文采用氧弹量热法对几种常用建筑材料的燃烧热值进行测试,并对试验数据进行对比分析,试验结果表明不同建筑材料的燃烧热值差别很大,酚醛和木纤维材料燃烧热值极高;胶粘剂、喷涂棉和玻璃棉制品次之;硅钙板、矿棉板和珍珠岩热值较低,甚至个别材料燃烧热值出现负值。本文旨在为建筑材料在工程防火中的应用提供参考。     

汽车门板材料燃烧特性及火灾危险性研究

使用锥形量热仪研究汽车典型门板材料（聚丙烯蜂窝板填料/包覆层组合件）在15、25、35、45 kW/m2热辐射功率条件下的点燃时间、热释放速率及热释放总量等特性参数。引入火灾性能指数、火灾增长指数,利用Petrella评价体系分析各组合件的火灾危险性。结果表明,PP-PVC较难被点燃,具有高火灾性能指数和低火灾增长指数,PP-PVC组合件火灾危险性较低。     

The effects of ply organization and loading direction on bending strength and modulus of elasticity in laminated veneer lumber (LVL) obtained from beech (Fagus orientalis L.) and lombardy poplar (Populus nigra L.)

The effects of ply organization and loading direction on bending strength and modulus of elasticity in laminated wood materials produced from 3 mm thick veneers, of beech (Fagus orientalis L.) and lombardy poplar (Populus nigra L.) placed one on top of the other in various arrangements were examined in this study. Kleiberit 303 (PVAc), a vinyl (polyvinyl acetate – PVAc) based glue was used in lamination. Eight hundred samples were prepared in order to measure oven-dry specific gravity, bending strength and modulus of elasticity values perpendicular and parallel to the glue line of a total of 10 different arrangements, eight of which have different laminated ply organizations, namely (AAAAAAA) (7A), (BBBBBBB) (7B), (ABBBBBA), (ABABABA), (AABBBAA), (AABABAA), (ABBABBA), (BABABAB), in which (A) represents beech wood and (B) represents poplar wood and the other two, which consist of solid beech and solid poplar wood in same dimensions as control samples. The samples were subjected to tests perpendicular and parallel to the glue line in accordance with the ISO 16978 standard. As a result of statistical analysis of the data obtained from the tests, the bending strength and modulus of elasticity values of solid woods both perpendicular and parallel to the glue line were observed to be smaller than those values of laminated woods made of the same species of woods. It was also observed that as contribution rate of beech in lamination increases, the bending strength and modulus of elasticity values increase.     

层合板壳振动控制LQR方法的理论推导

从层合板壳弹性力学基本方程出发,考虑各种因素影响,导出统一形式的振动方程,利用LQR最优控制理论,根据能量原理确定了Q,R,求出符合条件的最优控制集中力,等效分布荷载的表达式及位移衰减函数。     

入世对建材行业的影响

“入世”对我国建材企业来说 ,既是机遇 ,也是挑战。对入世后的水泥、陶瓷等几种建材情况作了简要分析 ,提出了提高建材行业整体竞争能力应采取的对策     

改性橡胶木力学性能试验研究

经过物理和高压化学处理后,改性橡胶木具有良好的防火和耐腐蚀性能.为促进改性橡胶木在结构工程中的应用,对其进行力学性能试验,研究其在不同加载条件下的破坏模式、材料性能、强度和刚度,并与市面上常见的天然木材和胶合木材的试验结果进行对比.试验结果表明,改性橡胶木具有良好的力学性能,可与天然木材相媲美,为改性橡胶木在木结构工程中的应用提供基础依据.     

玻璃纤维增强胶合木的力学性能试验研究

研究玻璃纤维布(GFRP)增强胶合木质工程材料的基本力学性能。通过试验测试,比较GFRP增强胶合木与普通胶合木的力学性能差异,考察GFRP含量及布置方式对胶合木力学性能的定量影响。结果表明:增加GFRP含量能够有效提高胶合木的静曲强度,合理的GFRP栅格布置能够提高胶合木的胶合剥离破坏强度,GFRP含量及布置方式对胶合木的弹性模量影响很小。最后,建立了考虑GFRP含量及布置方式影响的GFRP增强胶合木的静曲强度数学模型。     

影响建筑材料燃烧热值测试结果的主要因素及解决措施

用等温式全自动热量仪对建筑材料的燃烧热值进行测试,分析和探讨了测试过程中影响燃烧值测试结果的主要因素,并提出了一些简单、有效的解决措施,以提高燃烧热值测试结果的准确度及热量仪的稳定性。     

地聚物注浆材料性能研究

以P.O52.5水泥为基材,利用工业固体废弃物粉煤灰、矿渣粉、钢渣粉进行改性,采用单因素及多因素正交试验,探究地聚物注浆材料性能及最优配比。结果表明,粉煤灰掺量15%、矿渣粉掺量20%、钢渣粉掺量15%时效果最优,其中对注浆料的流动性和抗压强度的影响排序为粉煤灰>钢渣粉>矿渣粉;XRD和热重分析发现,在最佳配比下,随时间延长能有效促进水化反应,钙矾石含量增多,可显著提升材料的强度和膨胀性。     

混凝土材料结合性能研究

针对混凝土薄弱的结合面—界面进行奇异性分析,对混凝土材料进行了混凝土中界面力学分析,得到了基于平面分析的复合材料结合的一个指针,这对推动纤维混凝土的配比研究具有重要的意义。