改性沥青防水卷材耐久性初步研究

通过对SBS改性沥青防水卷材、APP改性沥青防水卷材及再生胶粉改性沥青复合胎(涤棉无纺布、高碱玻纤网格布复合)柔性防水卷材耐水性、耐候性的测试,分析其耐久性。以聚酯毡和无碱玻纤毡为胎体的SBS、APP 改性沥青防水卷材耐水性好;而以涤棉无纺布、高碱玻纤网格布制成的改性沥青复合胎防水卷材耐水性差。     

复合胎卷材在北京市场的应用及原因分析

1北京地区复合胎卷材应用情况改性沥青复合胎防水卷材在北京地区已使用十年以上的时间,至今仍是主流产品。据了解,北京的改性沥青卷材生产厂至今已发展到大小三十来家,基本是民营企业,绝大多数企业目前仍以生产涤棉无纺布-玻纤网格布复合胎卷材为主,其中一部分销往外埠。1994年以前,改性沥青防水卷材尚无国家标准,为便于控制质量,北京市建委制定了BJ?RZ01《弹性体沥青防水卷材》认证指标,指标中低温柔度为-15℃。1994年底,国家行业标准JC?T560—94《弹性体沥青防水卷材》发布实施,复合胎卷材不在其列,北京对复合胎卷材仍执行BJ?RZ01地…     

改性沥青防水卷材的胎基

介绍几种改性沥青防水卷材的胎基，对比纺粘法聚酯无纺布、玻纤织布、玻纤无纺布及破布毡／玻纤网格布复合胎的性能。分析不同胎基对改性沥青防水卷材生产工艺、施工及卷材性能的影响，纺粘法聚酯长丝无纺布综合性能相对较好。     

复合胎防水卷材及其标准

分析了目前涤棉无纺布和玻纤网格布复合胎防水卷材在生产和应用中存在的问题,针对该产品标准JC/T 690-1998的不足,提出了该标准修订的具体建议.     

关于沥青复合胎防水卷材

复合胎卷材在目前我国的防水市场上专指以涤棉纤维无纺布与玻纤网格布复合胎为胎基,以再生胶粉作为沥青改性材料生产的防水卷材。这种材料因沥青纸胎油毡限制使用以及价格因素近两年来发展迅速,工程应用量极大。但此产品因材料本身的缺陷,决定其应用具有很大的局限性,在GB50207-2002《屋面工程质量验收规范》中,仅被列入Ⅳ类“非永久性建筑”屋面防水层可选用材料之一,在GB50208-2002《地下防水工程质量验收规范》中未将其作为规定选用的材料。在实际应用中,有的厂家设法造假以进一步降低成本,使该材料性能达不到JC/T690标准的要求;更有厂家将此材料假冒、误用作SBS改性沥青防水卷材,有意或无意地扩大其使用范围。这些行为扰乱了我国防水材料市场,造成了防水工程质量隐患。本专题组织3篇文章,分析了我国复合胎卷材的发展原因,提出了目前在生产和应用中存在的问题及其危害性,探讨了该材料的适用范围。本刊策划此专题,旨在让广大读者对复合胎卷材有一个全面的认识,并了解其生产及应用中存在的问题。同时呼吁有良知的防水人非但应严格按产品标准组织生产,而且应严格按国家规范谨慎选材,将复合胎卷材限制在合理的应用范围内。     

复合胎标准工作会议在青岛召开

2005年9月6-7日在青岛召开了JC／T690（涤棉无纺布与玻纤网格布复合增强的改性沥青防水卷材》行业标准修订及《聚酯毡与玻纤网格布复合增强的改性沥青防水卷材》、《玻纤毡与玻纤网格布复合增强的改性沥青防水卷材》、《玻纤毡与聚乙烯膜复合增强的改性沥青防水卷材》行业标准制定的第一次工作会议。标准负责起草单位和行业中的专家及企业代表出席了会议。     

胶粉改性沥青复合胎体增强的防水卷材及其标准

介绍了JC/T690-2008《沥青复合胎柔性防水卷材》、JC／T1076-2008《胶粉改性沥青玻纤毡与玻纤网格布增强防水卷材》、JC／T1077-2008《胶粉改性沥青玻纤毡与聚乙烯膜增强防水卷材》、JC／T1078-2008《胶粉改性沥青聚酯毡与玻纤网格布增强防水卷材》等4项行业标准制修订的目的和标准主要内容,提出了贯彻执行新标准的措施。     

胶粉改性沥复合胎体增强的防水卷材及其标准

介绍了JC/T 690-2008<沥青复合胎柔性防水卷材>、JC/T 1076-2008<胶粉改性沥青玻纤毡与玻纤网格布增强防水卷材>、JC/T 1077-2008<胶粉改性沥青玻纤毡与聚乙烯膜增强防水卷材>、JC/T 1078-2008<胶粉改性沥青聚酯毡与玻纤网格布增强防水卷材>等4项行业标准制修订的目的和标准主要内容,提出了贯彻执行新标准的措施.     

欧洲沥青防水卷材基的发展

概述欧洲沥青防水卷材胎基的发展，重点探讨了聚酯纺粘无纺布作为防水卷材胎基的优点，介绍了Johns Manville开发的新一代玻纤无纺布－聚酯长丝无纺布复合胎基的特点和应用前景。     

2003年建筑防水卷材产品质量国家监督抽查结果

国家质检总局近期对建筑防水卷材产品质量进行了国家监督抽查。本次抽查了7个省、直辖市29家企业生产的29种产品,合格22种,产品抽样合格率为75.9％、其中SBS卷材抽查了24种,合格18种,抽样合格率为75.0％;APP卷材抽查了5种,合格4种,抽样合格率为80.0％。 抽查结果表明,虽然本次抽查合格率比以往有所提高,但也存在着不少质量问题,尤其是弹性体改性沥青防水卷材(即SBS卷材),具体存在的问题: (1)使用价格低廉的无纺布、网格布或短纤聚脂胎作为胎基。标准中明确要求使用玻纤毡、聚酯     

膜分离器的经济膜透能力

膜分离器中透过膜的流体的产量不仅与膜本身的透过能力(膜面积与厚度之比)相关,还与操作条件、膜两侧流体流动状态等因素有关,膜产量不会随着膜透能力的增加而线性增加。提出并定义了经济膜透能力的概念。以生产氢气的钯膜分离器为例,考虑了7种膜两侧气体流动的状况。以其中的一种流动状态为例,计算了膜产量与膜透能力的关系以及经济膜透能力。经济膜透能力的概念可以指导膜分离器的设计和运行。     

膜生物反应器中的膜污染研究综述

介绍了膜污染机理,阐述了膜污染的影响因素及对于膜生物反应器中膜污染的研究近况,并提出相应的膜污染控制措施,从而为今后对膜污染的研究工作指明方向和提供宏观上的指导,以期推广该工艺在实际工程中的应用。     

Effect of temperature shocks on membrane fouling in membrane bioreactors

Temperature is known to influence the biological performance of conventional activated sludge systems. In membrane bioreactors (MBRs), temperature not only affects the bioconversion process but is also shown to have an effect on the membrane performance. Four phenomena are generally reported to explain the higher resistance for membrane filtration found at lower temperatures: (1) increased mixed liquor viscosity, reducing the shear stress generated by coarse bubbles, (2) intensified deflocculation, reducing biomass floc size and releasing EPS into the mixed liquor, (3) lower backtransport velocity and (4) reduced biodegradation of COD. Although the higher resistance at low temperatures has been reported in several papers, the relation with supernatant composition has not been investigated before. In this paper, the composition of the soluble fraction of the mixed liquor is related to membrane performance after exposing the sludge to temperature shocks. Flux step experiments were performed in an experimental system at 7, 15, and 25° Celsius with sludge that was continuously recirculated from a pilot-scale MBR. After correcting the permeate viscosity for temperature, higher membrane fouling rates were obtained for the lower temperature in combination with low fouling reversibility. The soluble fraction of the MBR mixed liquor was analysed for polysaccharides, proteins and submicron particle size distribution. At low temperature, a high polysaccharide concentration was found in the experimental system as compared to the MBR pilot. Upon decreasing the temperature of the mixed liquor, a shift was found in particle size towards smaller particles. These results show that the release of polysaccharides and/or submicron particles from sludge flocs could explain the increased membrane fouling at low temperatures.     

与混凝土反应粘结密封防水的CPS反应粘防水卷材

介绍了一种能与现浇混凝土或水泥凝胶反应粘结并与混凝土基层形成界面反应密封层的新型功能防水卷材,同时对该防水卷材与现浇混凝土或水泥凝胶反应粘结的机理以及防水特色进行了探讨和说明。     

砖胎模与木胎模成本分析

针对零层板结构施工模板问题,对比分析了采用砖胎模与木胎模的工艺及成本,得出砖胎模成本高于木胎模的结论,指出在施工过程中采用支设木胎模会明显降低施工成本,能大幅提高施工企业经济效益。     

膜结构建筑展望

通过对膜结构建筑的类型、材料、特点的分析及实例介绍 ,展望膜结构建筑在 2 1世纪的发展趋势。     

关于自粘屋面卷材的一点看法

如今，人们对屋面防水卷材的质量要求越来越高，既有环保方面的要求如无毒、无味、不损健康，又要节能．而且价格还要便宜。因此，沥青基和非沥青自粘屋面卷材再一次被引入屋面行业。自粘卷材并不是一个新概念，第一个自粘屋面卷材系统早在30年前就已问世。30年来自粘配方有了相当程度的改进和修改，但它们与     

膜材与膜建筑

膜材与膜建筑是近年发展较快的新型建材与建筑结构形式．介绍膜材种类、膜材制作及膜材的力学性能。对近年膜建筑普遍采用的几种基本结构形式及其优点与应用．膜建筑设计中结构找形与结构荷载分析，膜材裁剪等对膜结构最终效果影响因素作重点阐述，并列举膜建筑的适用领域。     

In-situ utilization of generated electricity in an electrochemical membrane bioreactor to mitigate membrane fouling

How to mitigate membrane fouling remains a critical challenge for widespread application of membrane bioreactors. Herein, an antifouling electrochemical membrane bioreactor (EMBR) was developed based on in-situ utilization of the generated electricity for fouling control. In this system, a maximum power density of 1.43 W/m³ and a current density of 18.49 A/m³ were obtained. The results demonstrate that the formed electric field reduced the deposition of sludge on membrane surface by enhancing the electrostatic repulsive force between them. The produced H₂O₂ at the cathode also contributed to the fouling mitigation by in-situ removing the membrane foulants. In addition, 93.7% chemical oxygen demand (COD) removal and 96.5% ₄NH⁺-N${{\text{NH}}_4}^{+}-\text{N}$ removal in average as well as a low effluent turbidity of below 2 NTU were achieved, indicating a good wastewater treatment performance of the EMBR. This work provides a proof-of-concept study of an antifouling MBR with high wastewater treatment efficiency and electricity recovery, and implies that electrochemical control might provide another promising avenue to in-situ suppress the membrane fouling in MBRs.     

Recent advances in membrane bioreactors (MBRs): Membrane fouling and membrane material

Membrane bioreactors (MBRs) have been actively employed for municipal and industrial wastewater treatments. So far, membrane fouling and the high cost of membranes are main obstacles for wider application of MBRs. Over the past few years, considerable investigations have been performed to understand MBR fouling in detail and to develop high-flux or low-cost membranes. This review attempted to address the recent and current developments in MBRs on the basis of reported literature in order to provide more detailed information about MBRs. In this paper, the fouling behaviour, fouling factors and fouling control strategies were discussed. Recent developments in membrane materials including low-cost filters, membrane modification and dynamic membranes were also reviewed. Lastly, the future trends in membrane fouling research and membrane material development in the coming years were addressed.