塑料土工格栅的性能及应用

分析塑料土工格栅的一般性能及蠕变特性,介绍塑料土工格栅在软地基加固、路面处理、加筋挡土墙及护岸墙、边坡防护、不同沉降量基础间的过渡处理及水土流失治理等岩土工程中的应用,指出我国在塑料土工格栅研究上存在的问题,并展望塑料土工格栅的应用前景。     

塑料土工格栅拉伸过程的试验研究

通过试验研究了塑料土工格栅的拉伸过程,总结了结晶聚合物土工格栅试样拉伸的一般规律,根据聚合物拉伸理论解释了试验现象,并探讨了塑料土工格栅连续稳定拉伸的条件。试验表明,塑料土工格栅试样的各成肋部分沿纵向被依次拉伸伸长是连续生产的基础;可由材料的应力-应变关系初步判定塑料土工格栅试样拉伸的连续性,这对新型塑料土工格栅材料、工艺的研发,缩短试验周期是有利的。     

土工格栅与不同粒径填料界面作用特性试验研究

路基边坡加筋设计时,土工格栅与填料间的界面作用特性是影响加筋边坡工程安全与稳定的重要因素.为研究土工格栅与不同粒径填料的界面摩擦特性,进行了土工格栅与3种不同粒径均匀粗粒土的拉拔试验,分析了法向应力、填料粒径和拉拔速率3个因素对界面参数的影响.试验结果表明:土工格栅所受的最大拉拔力,随着填料粒径和拉拔速率的增大而增大,但填料粒径比拉拔速率的增幅大;不同粒径或不同拉拔速率下,格栅-土的界面最大剪应力与法向应力均呈线性拟合关系;填料粒径的增大显著提高了界面参数似黏聚力,但对似摩擦角变化不明显;拉拔速率的增大,使得界面参数似黏聚力几乎呈线性增长,而似摩擦角变化不明显.该试验结果对加筋边坡工程的设计具有一定的参考价值.     

塑料土工格栅的生产开发

综述了塑料土工格栅的生产开发进展．着重介绍了塑料土工格栅原料(聚丙烯、聚乙烯)、生产工艺、性能指标、生产企业．并提出了我国加快塑料土工格栅生产开发的建议。     

塑料土工格栅的长期性能与质量保证

利用时温叠加原理和最小偏差原理,对同一系列多种规格的高密度聚乙烯（HDPE）单向拉伸土工格栅在不同温度下的蠕变性能进行测试,并结合数学方法在短期内预测其长期性能。该方法置信度高,可广泛应用于塑料土工格栅质量保证及工程设计中,大大减小了工程设计的误差,确保了塑料土工格栅使用的安全性。     

塑料土工格栅的生产、应用及发展趋势

阐述了塑料土工格栅加固土体的作用机理,介绍了土工格栅的生产工艺流程及其在土木工程中的应用,探讨了格栅的发展趋势及存在的问题.     

塑料格栅填料的开发与应用

介绍塑料格栅填料的特点，在易淤积的塔器中使用塑料格栅填料，可提高传质效率，降低运行阻力。塑料格栅填料是一种高效、低阻力、大通量的规整填料。     

关于塑料土工格栅冲孔模具的相关研究

冲孔模具在塑料土工格栅产品生产中占据着十分重要的地位,并且冲孔模具参数也会直接影响到生产产品的拉伸强度、单位面积质量等,加强塑料土工格栅冲孔模具研究就非常有必要。本文联系塑料土工格栅的基本概述,对塑料土工格栅生产工艺、冲孔装置、模具参数等进行细致的分析,并围绕冲孔模具工作失效问题,尝试从优化模具参数、合理模具结构、选用合适钢材、加强模具维护等方面入手,提出几点有效应对策略,以供参考。     

塑料土工格栅蠕变性能测试方法探讨

研究了塑料土工格栅蠕变性能与拉伸强度之间的关系,并证明了塑料土工格栅蠕变行为符合时温等效原理,应用时温等效原理可在较高温度下试验得到较低温度下更长期的设计强度。     

简讯

塑料格栅填料的应用 用PVC、PP等制成的塑料格栅填料具有比表面积大,表面光滑,具有通气量大、压降小、抗堵性强等突出优点,价格低廉,可以低成本对旧的填料塔改造,是木格栅填料替代品。塑料格栅是以塑料型材加工而成,不造成环境污染,用该产品替代木格栅填料后,可节约大量小材,对环境保护、生态平衡具有积极的意义,专家建议在氮肥行业内推广使用。 塑料格栅是由塑料板、棒、管,经过加工后根据塔径、入     

Plastic damage mechanisms of polypropylene/polyamide 6/polyethelene-octene elastomer blends under cyclic tension

A series of three-phase polymer blends, composed of polypropylene (PP) matrix, polyamide-6 (PA6) fillers and polyethylene-octene elastomer grafted with maleic anhydride (POE-g-MA) modifiers, were designed and manufactured. Their mechanical behavior under cyclic loading-unloading was studied by using a video-controlled testing system named as VideoTraction^© system. It was found that with the increasing PA6 and POE content, the strain hardening became more and more prominent, the volume strain decreased, and the energy dissipated increased. A detailed examination of the cryo-fractured surfaces under SEM was undertaken. The microcavity nucleation, growth and coalescence were observed, and represent the main mechanisms of plastic deformation and damage. The high volume strain comes from the abundant formation of microvoids. On the contrary, the formation of microvoids resulted in relatively smaller quantity of energy dissipation. This result coincides well with the toughening mechanisms of polymer blends revealed by other peoples.     

Scratch Damage in Zirconia Ceramics

Scratch damage modes in zirconia-based ceramics—Mg-PSZ, Y-TZP, and Ce-TZP—are investigated. Precursor indentation tests with a tungsten carbide sphere foreshadow the nature of damage: in Mg-PSZ, extensive (quasi-)plastic deformation in the region outside and beneath the contact; in Y-TZP, less plastic deformation beneath the contact but incipient cone cracking in the region of tension outside the contact; in Ce-TZP, intermediate behavior. Scratch testing is conducted using a conical diamond indenter. In all materials the damage mode changes from smooth plastic deformation to limited cracking with increasing scratch load: in Mg-PSZ, plastic deformation is predominant at lower loads, with microcracking at higher loads; in Y-TZP, plastic deformation is predominant over the range of the test loads—macrocracks initiate only at relatively high loads, but penetrate to a relatively large depth; again, Ce-TZP shows intermediate behavior, but with cracking patterns closer to that of Mg-PSZ. Bending tests on specimens subjected to scratch damage indicate a relatively high damage tolerance in the Mg-PSZ and Ce-TZP; Y-TZP shows the highest initial strength, but suffers relatively large strength loss above the critical load for macrocracking. Implications concerning relative merits of each zirconia type for wear properties, contact fatigue, and machining damage are briefly discussed.     

尾矿砂改性混凝土的强度与声发射损伤特征研究

为了研究尾矿砂改性混凝土的受压损伤特征,对4组不同磷矿尾矿砂取代率的混凝土进行了单轴压缩-声发射监测试验。根据混凝土受压损伤时所释放的声发射(AE)信号,定量探讨了材料的损伤程度,并以AE指标为基础分析了混凝土损伤演化特征。结果表明:混凝土的应力-应变曲线可分为弹性变形、塑性变形、断裂破坏和残余变形4个阶段;随着尾矿砂含量增加,混凝土的抗压强度先增加后保持稳定,尾矿砂取代率为30%(质量分数)的改性混凝土峰值抗压强度最大;由AE信号提出了损伤因子,损伤因子-应变曲线表明普通混凝土的结构损伤主要在塑性变形阶段,而尾矿砂改性混凝土的结构损伤集中在塑性变形和断裂破坏阶段;一定比例的磷矿尾矿砂有助于提高水泥砂浆的密实度,从而增强抗压强度和变形性能。这为尾矿砂改性混凝土的研究提供了重要参考。     

有机/无机填料混杂增强木塑复合材料制备与性能

针对木塑复合材料力学性能较低和湿热环境下易变形的不足,研究了矿物填料和木粉混杂增强高密度聚乙烯(HDPE)木塑复合材料的力学性能和湿热特性,初步分析了矿物填料微观结构和增强作用的关联关系。结果表明,添加矿物填料对木塑复合材料的弯曲、拉伸和冲击性能有不同程度的改善作用,对模量的提高尤为明显。具有丝束或丝絮状纤维结构的海泡石、硅铝酸纤维和硅灰石对木塑复合材料的增强作用要低于具有长条状纤维结构的水镁石纤维,纤维缠结导致的分散困难可能是其增强作用差的主要原因。海泡石对耐热温度和洛氏硬度的提高作用要优于其它矿物填料,添加了25份海泡石纤维的木塑复合材料的硬度和耐热温度分别提高57. 7%和26%。     

PE纤维胶丝束拉伸损伤过程的声发射特性研究

研究了聚乙烯(PE)纤维胶丝束拉伸损伤过程中的声发射(AE)特性,确定了PE纤维胶丝束拉伸损伤过程中不同损伤阶段的AE特性,得到了不同损伤类型的AE参数特征。研究发现,判定PE纤维胶丝束失效的依据是出现幅度大于90 dB、持续时间大于1042μs的AE信号。     

礁石粉对超高强混凝土工作性能和力学性能的影响研究

采用礁石粉取代部分(0％、10％、20％以及30％)水泥时,对比研究了礁石粉对超高强混凝土(UHSC)流变性能、流动度和强度的影响,利用XRD、DTG方法研究了礁石粉对UHSC水化产物的影响.结果表明,浆体的屈服应力和塑性粘度随礁石粉掺量的增加先减小后增大,礁石粉掺量为10％时的屈服应力和塑性粘度最小分别为2.46 Pa、3.29 Pa·s;掺入适量的(≤20％)礁石粉能提高UHSC的流动度,礁石粉掺量为10％时的UHSC流动度最大为330 mm;30％以内掺入礁石粉能提高UHPC的抗压强度,且对UHSC的3 d抗压强度提高最明显;礁石粉的加入可以显著降低水泥水化放热峰值,礁石粉掺量越大,水化放热峰值降低的越明显,礁石粉的加入能明显推迟水泥水化放热达到峰值的时间;XRD和DTG结果表明礁石粉并不改变水化产物的种类.     

Green composites of organic materials and recycled post‐consumer polyethylene

Addition of organic fillers to post‐consumer recycled plastics can give rise to several advantages. First of all, the cost of these fillers is usually very low, the organic fillers are biodegradable contributing to an improved environmental impact and, last but not least, some mechanical and thermomechanical properties can be enhanced. Organic fillers are not widely used in the plastic industry although their use is increasing. Bad dispersion into the polymer matrix at high‐level content and poor adhesion with the matrix are the more important obstacles to this approach. In this work various organic fillers have been used with a post‐consumer plastic material originating from films for greenhouses. The properties of these green composites have been compared with those of materials filled with a conventional inorganic filler. The organic fillers cause slightly worse processability, due to an increase of viscosity, an enhancement of the rigidity and of the thermomechanical resistance similar to that measured for the inorganic filler, while a reduction of the impact strength is observed. Copyright © 2004 Society of Chemical Industry     

塑料热变形温度测试影响因素研究

通过对几种塑料采取多种方法测试其热变形温度,研究了热变形温度测试结果的影响因素。结果表明,同种材料不同测试方法所得到的热变形温度值有差异,且同一样品采取相同测试方法的热变形温度值随起始温度的升高而变大,但硅油粘度的变化对测试结果基本没有影响。     

Mineral fillers in low density-polyethylene films

The use of fillers is an established method of modifying the properties of plastics. The recent increase in prices of plastic raw materials and the new developments in compounding technology have heightened the interest of the plastic industry in compounds of fillers and polyethylene. This article discusses briefly the literature dealing with the effect of fillers on the properties of polyethylene, and research carried out on the effects of different mineral fillers, talcs, micas, clays, wollastonite and dolomite on the many properties of low density polyethylene films. The fine grade talcs have proved to be better than the other fillers with respect to most film properties. The platy talcs decreased the oxygen permeability by as much as 80 percent and the water vapor transmission rate by as much as 70 percent. With talcs, clays and dolomite the yield strength increased but with all fillers the tensile strength at break weakened with increasing filler content. A low elongation at break and a low tearing, resistance indicate the brittleness of the films especially at high filler contents (over 30 wt percent). The coefficients of friction decreased considerably with all fillers and a significant improvement in printability was achieved. However, none of the fillers had more than a very minor effect on the heat sealability of low density polyethylene.