【作者】 刘丹；

【导师】 李克非； 许建春；

【作者基本信息】 清华大学 ， 建筑与土木工程， 2010， 硕士

【摘要】 混凝土结构耐久性能的优劣,关系到国民经济与老百姓生命财产的安全,混凝土结构耐久性的研究,在当今的混凝土研究和土木中占有重要的地位。盐冻条件下混凝土耐久性的研究是该领域的重要组成部分。当前盐冻环境主要产生于冰雪气候条件下除冰盐的大量使用。在混凝土结构基本处于带损伤工作的现实情况下,损伤能多大程度上促进盐冻环境对混凝土耐久性的破坏,对于我们研究混凝土耐久性研究有着非常重要的现实意义。盐冻对钢筋混凝土结构的破坏作用主要体现在两个方面:一、混凝土表层的剥蚀破坏;二、除冰盐中的氯离子向结构内部逐步渗入,造成钢筋的锈蚀。目前阶段对盐冻的两种破坏作用的研究尚未达到定量的阶段,缺乏一个有效的模型来建立损伤程度与使用年限之间的关系。本论文的研究目的就是选取桥面板作为研究对象,探讨现行建筑标准下,桥面板耐久性问题,并结合研究成果,对目前我国公路桥梁的构造提出合理化建议。本研究通过干湿循环对试件制造不同程度的损伤,通过超声波仪器对不同程度损伤进行界定。然后将盐溶液置于特制的损伤试件中,进冻融箱进行冻融循环试验,测试不同循环次数下氯离子渗入的浓度以及混凝土表面的剥蚀情况。建立数学模型,对数据进行分析,建立循环次数与盐冻损伤之间的关系模型。通过模型计算不同地区冬季混凝土盐冻损伤,针对桥面板这一除冰盐危害较为严重的研究对象,推导现行规范条件下的使用年限,提出改进建议。研究发现,在盐冻损伤环境下,现有公路桥梁构造已无法满足现行建筑标准对使用年限的要求,需要对建筑标准进行很大程度的修正,并在施工环节采取一定的措施,否则我们只能改变撒除冰盐这一传统的,目前为止也是唯一行之有效的除冰除雪的手段。基于此本课题针对桥面板这一研究对象,提出了建议:(1)增加桥面板调平层厚度,有效阻止氯离子侵入;(2)抗拉区使用环氧涂层钢筋;(3)增加调平层混凝土强度等级;(4)在调平层与保护层之间设置一层隔离层。并进行了计算,均可行。更多还原

【Abstract】 The merits of durability of concrete structures are related to safety of the national economy and people’s lives and property, Studies in durability of concrete structures play an important position in today’s concrete research and civil, durability of concrete in salt frozen conditions is an important part of this field. At present,the is mainly occurred in the extensive use of deicing salt in the ice cold weather conditions. Basically, with the realities that most of concrete structure had work injury,how does pre-existed concrete injury enhance the damage to concrete durability caused by salt frozen situation, will have a practical significance to the study of concrete durability.Salt frozen on the destructive effects of reinforced concrete structures is mainly reflected in two aspects: First, the concrete surface erosion damage; second, deicing salts, the chloride ion in the gradual infiltration of the internal structure, causing steel corrosion. At this stage of the destruction of the salt freezing effect of the two has not yet reached the stage of quantification, the lack of an effective model to create a life of injury and the relationship between. Purpose of this study is to select the bridge slab as the research object of the current building standards, the bridge slab durability issues, combined with research on the current rationalization of highway bridges recommendations.In this study, wet and dry cycles of the specimen to create different degrees of damage, through the ultrasound equipment to define the different damage levels. Salt solution and then placed in a special specimen damage, into the freezing and thawing the freeze-thaw cycle test cases, test cycles under different concentrations of chloride ion penetration and the concrete surface erosion situation. Mathematical model, the data analysis, number of cycles and the relationship between salt and cold injury model. Calculated by the model of salt in different parts of the winter freeze damage of concrete for bridge slab deicing salts damage to this more serious object of study, under the existing norms derived useful life, make recommendations for improvement.Found that freezing injury in the salt environment, the existing highway bridge construction can not meet current building standards requirements on the use of life, the need for building a large degree of amendments to standards, and certain measures are taken in the construction, otherwise we only sprinkle deicing salts can change this tradition, so far the only effective means of deicing snow. Based on this, the subject of this study for the bridge slab, made recommendations on: (1) increasing the thickness of the bridge panel leveling, effective organization of chloride ion intrusion; (2) the tensile zone of reinforced epoxy coating applied to protect the steel; (3) increasing the leveling layer of concrete strength; (4) leveling layer and the protective layer, a layer of isolation between the wiping layer. And calculated, are feasible.更多还原