国外玻璃钢老化问题的试验研究

介绍了国外在不同环境下对玻璃钢性能老化影响的试验研究结果。     

玻璃钢老化问题的试验研究

玻璃钢亦称为玻璃纤维增强塑料，在各方面的应用日益广泛，因此如何提高这种制品的使用寿命，防止或延缓外界因素对其性能的影响，即老化问题，在国外受到普遍重视。特别是从上世纪六十年代以来，各国都广泛地使用玻璃钢。美国从1960年以来，相继制造了《民兵》、《北极星》、《先锋》、《海神》等导     

国外关于玻璃钢老化问题的试验研究

本文介绍了国外关于在不同环境下对玻璃钢性能老化影响的试验研究。     

国外关于玻璃钢老化问题的试验研究

本文介绍了国外关于在不同环境下对玻璃钢性能老化影响的试验研究。     

PVC型材老化问题探讨

塑料门窗在行业内全体人员的努力下经过几年来的奋斗,目前已基本得到了人们的认可。作为一项节能门窗被广泛采用,其普及率越来越高。然而,对于我们国家这样一个地域辽阔的大国,分布于热带、亚热带、温带、寒带的不同地域,光照强度、时间、湿度都决非一致。     

透光玻璃钢的研制及应用

透光玻璃钢是一种复合材料类的采光材料,与现有采光材料(玻璃)相比,它具有独特的优点,如强度高、有韧性、不易碎、易成型等,因此在工业与民用建筑中得到日益广泛的应用。经过多次试验,我们研制成功了透光的玻璃钢,本文即介绍其研制及应用情况。一、原材料选择玻璃钢是一种复合材料,光线照射在其表面后,不仅从表面反射掉一部分,还在玻璃纤维和树脂界面发生反射和折射。反射和     

玻璃钢再生料对RPC工作性及力学性能影响试验研究

将玻璃钢废料进行切割-粉碎-筛分处理,得到了玻璃钢再生纤维、再生粉末两种原料,并分别代替耐碱玻璃纤维和石英砂制备了活性粉末混凝土(RPC),研究了玻璃钢再生料对RPC力学性能的影响。结果表明,以玻璃钢再生纤维代替耐碱玻璃纤维制备RPC时,新拌RPC的流动性变化不大,力学性能略有降低。以玻璃钢再生粉末代替石英砂制备无纤维RPC时,新拌RPC的流动性随玻璃钢再生粉末掺量的增加而略有降低,但力学性能有明显提升。     

SHRP试验在我国沥青老化研究中的进展

为促进SHRP试验在沥青老化研究中的应用,推动老化沥青的力学性能研究.本文首先介绍了沥青老化影响因素,以及旋转薄膜烘箱试验(RTFOT)和压力老化试验(PAV)模拟沥青老化的研究进展;其次分别阐述了老化时间对沥青各温度区间下的宏观力学表征的影响;最后分析表明各温度区间下沥青的力学性能随老化时间呈规律性变化,指数关系模型能够表征沥青在高温下的力学指标与老化时间的关系,但对沥青模拟老化与实际老化间的关系及构建低温力学指标与老化时间的关系模型仍需进一步研究.     

玻璃钢围覆加固钢筋混凝土偏心受压柱的试验研究

通过对钢筋混凝土偏心受压柱(包括小偏心受压及大偏心受压柱)外围覆玻璃钢强度性能的试验,测得了偏心受压柱的荷载-曲率及荷载-挠度曲线以及柱在围覆玻璃钢后的强度,得出了外围覆玻璃钢对提高柱抗压能力和变形能力的贡献.最后通过综合理论分析及参考<混凝土结构设计规范>,提出了实用的计算公式.此外,还对加固施工所采用的材料及施工方法提出了一些建议,也提出了当前在加固工程中采用这种材料需解决的问题,为今后在加固工程中采用这种新材料作了一些有益的工作.     

Application of improved hybrid bonded FRP technique to FRP debonding prevention

External bonding of fiber reinforced polymer (FRP) is one of the most efficient techniques for retrofitting and strengthening concrete structures. However, the bond interface is the weakest link in such retrofitted or strengthened concrete members, resulting in premature FRP debonding. Therefore, a newly improved hybrid bonded FRP (IHB-FRP) technique is developed in this paper for strengthening concrete members. Unlike the conventional mechanical fastening method, the mechanical fasteners in the technique do not penetrate the FRP strips and the capping plates serve to apply vertical pressure to the FRP strips. An experimental study on the flexural strength of IHB-FRP technique strengthened beams is conducted. It is found that all the beams strengthened with the IHB-FRP technique fail due to tensile rupture of FRP strips even for seven plies of FRP strips. Based on the experimental results, the effects of the steel reinforcement ratio, the number of FRP plies, and the fastener spacing on the ultimate load are evaluated. Finally, a simplified method is proposed for estimating the ultimate bending moment of the IHB-FRP strengthened beam. The validity of the method is verified with the experimental results.     

FRP自愈技术

美国伊利诺斯大学的科研人员研发了复合材料自愈技术。该技术是在复合材料中埋入愈合剂来自动修补细如发丝的裂纹。在复合材料的树脂基体中渗入含单体和一种相应的聚合催化剂的微囊。当复合材料中产生裂纹时,这些微囊破裂,释放出单体。单体与催化剂接触后发生聚合反应,使裂纹“愈合”。据研发者称,裂纹一旦愈合后,聚合物就能恢复其原始断裂韧性的90%。这种技术适用于制造飞机、车辆、医疗器材(如人造关节)等的复合材料。在这些材料中,裂纹往往难以探测和修补。因此,使用这种新技术就能够生产更安全、更可靠、更坚固和寿命更长的产品。FRP…     

FRP及FRP增强构件在海水环境中耐久性研究

针对目前国内外对FRP及FRP增强构件在海水腐蚀环境下的耐久性研究情况,分别从FRP材料及其配套树脂、FRP与基体界面的粘结性能和增强构件在海水腐蚀环境下的耐久性进行了综述,对研究中存在的不足做了简要的分析,并对进一步的研究工作进行了展望。     

高湿环境下FRP加固修复混凝土用粘接树脂的研究

本文论述了一种用于高湿环境下的FRP加固修复混凝土用粘接树脂的研究过程和性能.首先研究了不同种类的固化剂在高湿环境下的粘接性能和其它力学性能;其次,研究环氧树脂的类型对浸渍树脂性能的影响最后,研究了活性环氧稀释剂对高湿环境下使用的浸渍树脂粘接性能的影响.综合以上研究成果,开发出高湿环境下的FRP加固修复混凝土用粘接树脂,为特殊环境下FRP加固技术提供了一种新型材料.     

RC beams shear-strengthened with FRP: Stress distributions in the FRP reinforcement

Reinforced concrete (RC) beams may be strengthened for shear with externally bonded fibre reinforced polymer (FRP) composites through complete wrapping, U-jacketing or bonding on their sides only. The two main shear failure modes of such strengthened beams are FRP rupture and debonding. In both modes of failure, the contribution of the bonded FRP reinforcement to the shear capacity of the beam depends strongly on the stress (or strain) distribution in the FRP at the ultimate limit state. This paper presents a numerical study of the FRP stress distribution at debonding failure in U-jacketed or side-bonded beams using a rigorous FRP-to-concrete bond–slip model and assuming several different crack width distributions. Numerical results indicate that Chen and Teng’s early simple assumption [Chen JF, Teng JG. Shear capacity of FRP-strengthened RC beams: FRP debonding. Constr Build Mater 2003;17:27–41] for the stress distribution in the FRP results in satisfactory predictions for the effective FRP stress in most cases for both U-jacketed and side-bonded beams. However, it may become unconservative for side-bonded beams that have only light flexural steel reinforcement.     

Ageing of aluminium hydroxide flocs

The ageing processes of kaolinite suspensions flocculated with Al₂(SO₄)₃ under a variety of different but well-controlled flocculation conditions were studied by measuring their average diameter, diameter distribution, strength and electrophoretic mobility.Three periods could be distinguished in the ageing process. Initially shrinkage of the flocs is mainly due to cementation-aggregation. In the first 6–8 h, dependent on the flocculation conditions, the average diameter reduces from 500 to 220 μm. During the following 4 days a shrinkage to 180 μm occurs, mainly due to condensation-polymerization and crystallization. In the third period, the average diameter increases because of Oswald ripening of the crystals.During each period the change of the diameter as a function of age can mathematically be described by: d_f,i = d∞ + d′· t_i^+i−ω. With d_∞, d′ and ω constants dependent on the flocculation conditions.During ageing, the floc diameter distribution narrows. The shrinkage of the flocs during ageing is definitely not due to erosion of particles from the floc surface.The change of the electrophoretic mobility during ageing provides information on the thickness and homogeneity of the layer of insoluble hydroxides around the destabilized clay particles.The influence of a wide range of different flocculation process parameters on the floc ageing process is summarized, as is the influence of the ageing process on floc strength and floc density. The evolution of the effective floc density can be described by: .The constants K_p and a are functions of the ratio quantity of suspended solids vs coagulant dose.     

复材增强约束珊瑚骨料混凝土柱抗震性能试验研究

纤维增强复合材料具有轻质高强、耐腐蚀等优点,可广泛应用于海洋工程结构,从根本上解决传统工程结构面临的钢材锈蚀问题。将复材管、拉挤型材和珊瑚骨料混凝土进行组合应用,提出了一种复材增强约束珊瑚骨料混凝土组合柱,并通过拟静力试验对其抗震性能进行了研究。研究变量包括轴压比、复材管缠绕角度、复材管厚度,重点探讨了不同情况下组合柱的破坏模式、极限承载力、耗能以及延性特征等的变化规律。结果表明,所有试件破坏模式均为内部拉挤型材断裂,同时混凝土压碎。改变试件轴压比、复材管缠绕角度、复材管厚度会对试件抗震性能产生影响。     

Ageing in Unsuitable Places

Much of the focus of ageing in place policy is concerned with the provision of support to enable older people to age in the community in residences adapted to their needs. There has been little examination of why older people make choices to age in particular places in later life. In this paper, we drew on 143 interviews with older people in New Zealand to examine the narratives older people use to describe their housing preferences in later life. Older people drew upon personal and public narratives to story housing in later life, and construct four identifiable identities: ‘practical planner’, ‘rugged pioneer’, ‘where I belong’ and ‘rooted in place’. This analysis demonstrates that some older people do narrate decisions to age in ‘sensible’ places with good access to services and have clear plans for change as their physical health declines. Other older people live proudly in unsuitable places and do not wish for support to move or accommodations made to their housing. These older people draw upon narratives of place as foundational to their identity, of relationships with people both living and dead as social relationships that bolster their identity and of housing as part of situated lifelong narratives. Both the situation of their home and the condition of the home provide the backdrop to alternative narrative identities that require them to remain in housing because of, or irrespective of, its unsuitability. To understand the limitations and the possibilities of ageing in place, we need to identify the multiple narratives that structure the lives of older people. By doing so, we can support ageing in place processes that do not disrupt the strong identities that have been developed in and through housing.     

FRP桁架桥施工技术

伴随着FRP材料的飞速发展,一批FRP桥梁相继建成,但对FRP施工工艺的研究仍是一片空白.针对快速架设的FRP桁架桥,依据FRP材料的特性提出一套适合于FRP桁架桥的施工方法,该方法涉及从工厂生产、预制到现场吊装.结合已建成的FRP桁架桥实际工程,对各施工步骤的流程及施工过程中的控制要求进行了详细阐述,其中重点介绍了吊装时吊点的选择原则及选择方法.     

玻璃钢耐腐蚀性能

1 前言 玻璃钢不仅具有轻质高强、电绝缘、非磁性、耐高低温的优点,同时还具有耐酸、耐碱、耐油等优异性能,近年来广泛用于制造各种化工设备及装置,解决了化工、冶金、石油、轻工、纺织等生产部门的腐蚀问题,取得了很好的效果,玻璃钢在防腐蚀领域中已成为一种用量大、效益高的材料。 玻璃钢由于所采用的原材料不同、配方不同、