【作者】 郝聪杰；

【导师】 龙玲；

【作者基本信息】 中国林业科学研究院 ， 木基复合材料科学与工程， 2011， 硕士

【摘要】 水泥纤维板是以水泥为胶凝材料,用纤维作为填充增强材料制成的新型建筑墙体材料,它兼有水泥和木材的双重优点,如强度高、自重轻、防火、隔音等,可广泛用于非承重内外墙板、天花板、活动房等领域。水泥纤维板作为一种理想的建筑材料,在国外已应用的相当普遍,但我国对水泥纤维板的研究起步较晚,还没有得到广泛应用。本研究选用普通硅酸盐水泥作为胶凝材料,探讨利用桉树化学木浆纤维、竹浆纤维、杨树热磨木纤维等作为增强材料,采用半干法工艺制备纤维增强水泥复合板,并比较各增强纤维水泥复合材料的板材物理性能和分析各工艺因素对板材物理力学性能的影响情况,得出较好的生产工艺参数,为我国水泥纤维板的工业化生产提供参考数据;并借助扫描电子显微镜,探索纤维增强水泥复合材料的增强机理。研究结论如下:1.通过纤维形态分析,木浆纤维的纤维长度范围为2.03-2.97mm.,竹浆纤维的纤维长度范围为1.08-2.60mm,热磨木纤维的纤维长度范围为1.01-1.98mm,根据纤维分级标准木浆纤维属于长纤维,竹浆纤维和热磨木纤维均属于中等长度的纤维。2.木浆、竹浆和热磨木纤维三种纤维冷水抽出物中的总糖含量分别为11.38mg/g、36.55mg/g及62.96mg/g;木浆纤维中综纤维素含量为93.69%,竹浆纤维和热磨木纤维中的综纤维素含量分别为74.86%、73.69%;木浆纤维中冷水、热水、1%NaOH抽出物含量分别为4.75%、4.93%、6.26%,竹浆纤维中冷水、热水、1%NaOH抽出物含量分别为7.16%、7.70%、12.63%,热磨木纤维中冷水、热水、1%NaOH抽出物含量分别为8.85%、10.02%和26.76%。3.木浆纤维与水泥具有较好的相适性,可直接用于纤维水泥板的制备。竹浆纤维和热磨木纤维均对水泥有阻凝作用,其中,热磨木纤维最为严重。化学添加剂可以加快水泥的凝结硬化,减缓纤维中的抽出物和糖分等对水泥水化的不利影响,并且随着添加剂量的增加,促凝作用愈加明显;本研究选用硫酸铝作为促凝剂,且用量为水泥用量的1%时较适于水泥纤维板的制备。4.利用半干法制备木浆纤维增强水泥板是可行的。木灰比和水灰比均对板材的物理力学性能有显著的影响。本研究试验条件下,较佳的制板工艺参数为:木灰比为0.22,水灰比为0.42,目标密度为1.3g/cm~3。在此条件下,压制出的板材的静曲强度可达10~14MPa,弹性模量可达3200~3900MPa,内结合强度为0.81~0.94MPa,24h吸水厚度膨胀率为0.41%~1.26%,均达到水泥刨花板标准(GB/T 24312-2009)优等品的要求。5.制备竹浆纤维水泥板时须添加化学助剂,利用半干法可以压制出成型的竹浆纤维水泥板,板材的弹性模量、内结合强度及24h吸水厚度膨胀率等物理力学性能均达到GB/T 24312-2009《水泥刨花板》和JC/T 411-2007《水泥木屑板》的要求。竹灰比和水灰比均对竹浆纤维水泥板的物理力学性能有显著的影响。本研究中板材的静曲强度最大为8.76MPa,尚未达到合格要求,须对各原料的配比作进一步的试验。6.在制备木浆纤维增强水泥板的较佳工艺参数条件下,向木浆纤维中掺入热磨木纤维仍可以制备出满足标准要求的木浆-热磨木纤维增强水泥板,在满足标准要求的前提下,热磨木纤维在总纤维中的含量比例最大可以达到30%。7.通过利用实体显微镜和扫描电镜对制备的纤维增强水泥复合板材的微观结构及纤维在水泥基体中的分布状况进行了观察。水泥水化可形成大量的C-S-H凝胶,纤维与水泥基材料充分混合,在水泥浆中形成多项分布的网络支撑体系,降低了水泥在塑形收缩及冷冻时形成的张力,改善了板材的结构和性能。8.本研究的纤维增强水泥复合板实际密度均为1.3 g/cm~3左右,属轻质板材,适用于非承重的内墙板、天花板、地板等领域。更多还原

【Abstract】 Cement fiberboard is a kind of new building wall material, which the cement is the binder filled with fiber as reinforcing material. It combines the dual benefits of cement and timber, such as high strength, light weight, fire protection, sound proofing, and so on. It can be used for non-load bearing external wall panels, ceiling, activity rooms or other fields. As ideal construction material, the cement-based fiberboard has been applied quite common in foreign countries. However, our study about cement fiberboard has been recently started. It has not been used widely. In this study, the ordinary Portland cement was used as the cementations material, and the wood-pulp fiber, bamboo fiber and hot-mill fiber were used as reinforced material. The semi-dry process was applied to produce cement-based fiberboard, and then the physical properties of the composite boards and compared of various process factors on the physical and mechanical properties of fiberboard were analyzed, so as to obtain better production parameters. This study can provide reference data for the industrial production of cement fiberboard. At the end, the scanning electron microscopy was used to explore reinforced cement composite reinforcement mechanism. The results were as follows:1. Though the fiber morphological analysis, the fiber length range of wood-pulp fiber is 2.03~2.97mm, bamboo fiber is 1.08~2.60mm, hot-mill fiber is 1.01~1.98mm. Based on fiber classfication standard, the wood-pulp fibers are long fibers, bamboo fiber and hot-mill fiber are belonged to the middle length fibers.2. The total sugar contents of cold water extracts in the wood- pulp fiber, bamboo fiber and hot-mill fiber were 11.38mg/g,36.55mg/g,62.96mg/g.The holocellulose contents of wood-pulp fiber was 99.69%, the holocellulose contents of bamboo fiber and hot-mill fiber were 74.86% and 73.69%. The cold water extract, hot water extract, 1%NaOH extract from the wood-pulp fiber were 4.75%, 4.93%, 6.26%. The cold water extract, hot water extract,1%NaOH extract from the bamboo fiber were 7.16%,7.70%,12.63%.The cold water extract, hot water extract,1%NaOH extract from the hot-mill fiber were 8.85%,10.02% and 26.76%.3. Wood-pulp fiber and cement has better compatibility. It can be directly used for production of cement fiberboard. The bamboo fiber and hot-mill fiber both have blocking coagulation, in which the hot-mill fiber is the most serious. The chemical additives can accelerate the coagulation of cement hardening, slow the adverse effects on cement hydration from the extract and sugar in fiber. And with the increase in the amount of additives, the more obvious procoagulant effect will be. The use of Aluminum Sulfate as a coagulant, and the amount of 1% of the amount of cement is better for the preparation of the cement fiberboard.4. The semi-dry process can be used for the production of the fiber reinforced cement board. Wood cement ratio and water cement ratio both have a significant impact on the physical and mechanical properties of cement fiberboard. In this study, the better parameters for the board is: wood cement ratio of 0.22, water cement ratio of 0.42, the target density is 1.3g/cm~3, under these conditions, the MOR of board can up to 10~14MPa, the MOE can up to 3200~3900MPa, IB was 0.81~0.94MPa, 24h TS was 0.41%~1.26%, these data can up to the superior product requirements in Cement Particleboard (GB/T 24312-2009) .5. The chemical additives should be added while producing cement-based bamboo fiberboard. The semi-dry process can be used to suppress the bamboo fiber cement board. The physical and mechanical properties such as MOE, IB and 24hTS of the board could up to the requirements of GB / T 24312-2009 "cement particle board" and the JC / T 411-2007 "cement wood board". In this study, the MOR (which can up to 8.76MPa) can not yet reached the eligibility requirements, it should be further tested.6. In the better process parameters of preparing wood-pulp fiber reinforced cement board, to the incorporation of hot-mill fiber in the wood-pulp fiber can still produce the fiber reinforced cement board which could up to the standard requirements, in the premise of meeting the performance, the hot-mill fiber in the total fiber content can up to 30% of the largest share.7. Though the use of microscopes and scanning electron microscopy, the microstructure of the fiber reinforced cement composite board and fiber distribution in the matrix were observed. Cement hydration can form a large number of C-S-H gel. The fiber and cement-based materials mixed enough to form a network support system in the slurry, reducing the tension when the cement contraction and frozen, and then improve board structure and performance. 8. In this study, the actual density of the fiber reinforced cement composite boards is about 1.3g/cm~3, which belongs to lightweight board. It is possible to be applied for non-load bearing internal wall panels, ceiling, activity rooms and other fields.更多还原