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钢筋混凝土结构由于受到外界环境侵蚀的影响,导致结构本身的承载力降低,为了防止氯离子对结构物的侵蚀,分析了氯离子的侵入方式和钢筋锈蚀机理,探讨了氯盐环境下混凝土有机复合涂层研究现状,结果表明有机复合涂层混凝土能有效阻止氯离子对结构物的侵蚀,保护钢筋免于锈蚀,可以为工程实践提供重要的参考依据。 相似文献
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钢筋的腐蚀,尤其当有氯离子存在时,是混凝土结构腐蚀破坏的主要原因。本文介绍了环氧树脂涂层技术现状以及应用中出现的问题。 相似文献
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通过试验,研究混凝土强度、氯离子含量、钢筋保护层厚度和外部湿度对混凝土中钢筋腐蚀的影响。研究发现钢筋腐蚀速度随氟离子含量提高而增大;氯离子含量在0．1％到0．8％,腐蚀速度增加缓慢;氟离子含量在0．8％到2．0％,腐蚀速度增加显著。氯离子含量0．1％时,混凝土强度对腐蚀速度有影响;氯离子含量2．0％时,强度、湿度、保护层厚度对腐蚀速度都有显著影响,湿度的影响强于强度和保护层厚度。 相似文献
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混凝土碳化和氯离子腐蚀是引起混凝土构件破坏的两个重要原因,引起混凝土耐久性问题,大大降低混凝土结构的使用寿命。电场加速氯离子在混凝土中扩散的试验已经被广泛用来测试氯离子在混凝土中的扩散系数。 相似文献
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在盐雾环境中,氯离子的侵蚀是混凝土结构耐久性劣化的主要原因之一。在简述混凝土中氯离子侵蚀机理的基础上,采用盐雾试验箱进行近海结构混凝土盐雾条件下抗氯离子侵蚀性能的相关研究,研究了混凝土强度对氯离子扩散浓度的影响。研究结果显示,随着渗透深度上升,氯离子累积的沉积量会越变越小;改变配合比,提高混凝土的强度可以有效阻止氯离子向其内部扩散。 相似文献
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混凝土是建筑施工过程中必不可少的建筑材料之一,然而随着建筑行业技术的发展,各种混凝土的质量水平达不到建筑施工的要求,给我国的建筑行业带来了危机。本文从混凝土结构的腐蚀角度入手,针对当前我国存在的混凝土受氯腐蚀的问题,提出了一系列的加固处理方法,并结合相关的案例和试验的结构,重点分析了如何在氯离子的侵蚀下,保证混凝土质量的问题,供建筑施工人员参考。 相似文献
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介绍了海工高性能混凝土的配制及在大连长山大桥中的应用。北方海域海水盐分高、气候寒冷,对混凝土抗氯离子渗透性、抗冻性要求高,从原材料质量、配合比设计、施工几个方面分析如何才能满足要求。 相似文献
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介绍在混凝土中掺加高效抗腐蚀气密剂及钢筋阻锈剂、降低混凝土的水灰比、增加混凝土中水泥的用量、改善混凝土的施工操作方法等各种方法,有效提高的混凝土密实度和抗渗能力,并在施工过程中采用自动检测仪器对混凝土的耐久性进行检测,保证了抗海水腐蚀混凝土的实施质量。 相似文献
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钢筋混凝土基础的腐蚀与防护措施 总被引：2，自引：0，他引：2
概括了钢筋混凝土结构的腐蚀机理,归纳了影响钢筋混凝土基础的主要腐蚀因素及其作用规律.最后,对基础腐蚀的防护提出一些措施及建议. 相似文献
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Farzana Bano A. M. Kidwai R. K. Upreti R. K. Singh 《Indian journal of clinical biochemistry : IJCB》1994,9(2):109-111
The present studies with aluminium chloride given in drinking water showed marked inhibition in the activities of intestinal brush border membrane marker enzymes, namely alkaline phosphatase, acetyl cholinesterase, γ-glutamyl transpeptidase and sucrase. Moreover, a significant depression in the levels of membrane constituents, viz phospholipids, cholesterol, hexoses and sialic acid following aluminium chloride treatment was also observed. On the basis of these studies it may be concluded that if aluminium is taken in high quantities it may alter the structure and functioning of the intestinal brush border membrane, which in turn may lead to the improper digestion and reduced nutrient uptake from the small intestine. 相似文献
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黄永安 《科技成果管理与研究》2009,(2):78-81
利用9个已破坏的钢管混凝土试件,剖开钢管,取出管内混凝土,研究经历过三向应力作用后的钢管内混凝土的受力性能。将管内混凝土截成径高比接近的圆柱体试件,按混凝土立方体强度的标准试验方法,测得各试件的混凝土再次受压后的强度,绘出试件的应力-应变全曲线。研究表明,已经历过三向应力的混凝土再次受力性能与初次不同,但应力-应变曲线的形状和特征点与初次受力的混凝土相似。 相似文献
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碳纤维加固混凝土柱通过横向约束作用,提高柱的轴心受压承载力,增加柱的延性。利用碳纤维材料作围套加固混凝土轴心抗压柱,具有施工简单、抗腐蚀能力强、约束效果好等优点。 相似文献
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We report a molecular dynamics study on non-equilibrium dynamics of polyelectrolyte brushes under external electric fields. In this work, the effects of chain stiffness and salt concentration on static and dynamic responses of the brushes are addressed in detail. Our simulations indicate that varying these parameters induce rich electro-responsive behavior of the brushes. The increase of salt concentration results in the enhancement of an opposite electric field formed by non-equilibrium distribution of cations and anions, which resists stretching or shrinkage of grafted chains. At strong positive electric fields, the flexible brushes are more sensitive to the change of salt concentration. When reversing the electric field, the stiff brushes undergo a conformational transition from collapse to complete stretching. At high salt concentrations, dynamic responsive magnitude of the brush thickness to added electric field is strongly reduced. It was found that the fall time for the stiff brush becomes much shorter than that for the flexible brush. Additionally, increasing ion concentration leads to an excess extension or shrinkage of flexible brushes. For strongly stiff brushes, such phenomenon occurs in the presence or absence of salt. 相似文献
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高等级公路水泥混凝土路面沥青封层的设置与研究 总被引：1，自引：0，他引：1
本文结合广东梅河高速公路路面工程的施工实践,着重研究了沥青封层在水泥混凝土路面中的应用,通过铺筑多种不同材料组合的封层试验路段,验证了封层材料的适用性,提出了合理可行的施工工艺。 相似文献
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Luca Lanotte Giovanna Tomaiuolo Chaouqi Misbah Lionel Bureau Stefano Guido 《Biomicrofluidics》2014,8(1)
The confined flow of red blood cells (RBCs) in microvasculature is essential for oxygen delivery to body tissues and has been extensively investigated in the literature, both in vivo and in vitro. One of the main problems still open in microcirculation is that flow resistance in microcapillaries in vivo is higher than that in vitro. This discrepancy has been attributed to the glycocalyx, a macromolecular layer lining the inner walls of vessels in vivo, but no direct experimental evidence of this hypothesis has been provided so far. Here, we investigate the flow behavior of RBCs in glass microcapillaries coated with a polymer brush (referred to as “hairy” microcapillaries as opposed to “bare” ones with no coating), an experimental model system of the glycocalyx. By high-speed microscopy imaging and image analysis, a velocity reduction of RBCs flowing in hairy microcapillaries as compared to bare ones is indeed found at the same pressure drop. Interestingly, such slowing down is larger than expected from lumen reduction due to the polymer brush and displays an on-off trend with a threshold around 70 nm of polymer brush dry thickness. Above this threshold, the presence of the polymer brush is associated with an increased RBC deformation, and RBC velocity is independent on polymer brush thickness (at the same pressure drop). In conclusion, this work provides direct support to the hypothesis that the glycocalyx is the main factor responsible of the higher flow resistance found in microcapillaries in vivo. 相似文献