建筑火灾后混凝土的性能研究及实用鉴定方法

发布时间：2018-01-11 23:06

本文关键词：建筑火灾后混凝土的性能研究及实用鉴定方法　出处：《华北水利水电大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着社会的不断进步及城市化水平的提高,使得各类建筑火灾发生的频率迅速增加,进而严重威胁着人们的生命及财产安全。目前各类人们生产和生活使用的建筑、道路和桥梁建筑、水利和各种特种建筑结构中使用较为普遍的承重材料为混凝土。混凝土材料是一种具有多相的、热惰性的人工复合材料,其主要是由水泥作为粘结剂、砂和是作为粗细骨料与水按一定比例混合而成,具有良好的持久性能、抗火性能和整体性能。若混凝土材料长时间处在温度较高的环境下,或着是突然遭遇高温作用时,均能使得混凝土材料物理和化学性能发生重大改变。大多数的专家学者对不同高温作用后混凝土的性能进行研究时,主要考虑的是不同的温度作用对其产生的影响,除此之外,不同的冷却方式、过火时间、混凝土的强度等级等因素对其产生的影响则考虑的较少。为了对混凝土材料在高温或火灾作用后的性能进行较为准确的分析,因此我们需要考虑混凝土的力学性能与温度、过火时间、冷却方式等等因素之间的关系,进而为混凝土结构在高温或火灾作用后评估鉴定以及加固修复等工作提供支持依据。本文主要对多个强度等级的混凝土材料在经历不同过火温度、不同过火时间以及不同冷却方式处理后的抗压力学性能开展了必要的试验研究和理论分析。与此同时,结合此次实验的结果,提出了切实可行的过火后混凝土结构的鉴定方法。本文的具体工作如下:(1)通过对不同强度等级的混凝土试件进行各种类型的过火试验,实验结果表明:随着混凝土材料所遭受的过火温度及时间的延续,其表观颜色产生由浅到深的变化,另外,试件还出现了越来越严重的棱角缺失和表皮脱落等现象。同时,还得出了混凝土材料在火灾或高温作用后外表面的物理性能,例如表面颜色、外观损伤情况、质量减少情况等随过火温度和时间的变化规律。利用这些物理变化来推算出大致的火灾温度,进而为火灾或高温后的结构检测、鉴定及修复加固提供支撑依据;(2)采用国际标准ISO-834温升曲线对混凝土试件进行了过火实验,并选取了不同的过火时间,对混凝土试件的温度场进行研究分析;(3)通过试验研究了不同过火温度、不同过火时间下多个强度等级的混凝土试件抗压力学性能的变化情况,基于本文给定的不同强度等级的混凝土试件和试验设定的升温、恒温及冷却处理的方式,利用试件所得的相关数据拟合出了明火作用后混凝土的抗压强度与过火温度和时间之间的关系表达式;(4)本次试验还研究了过火作用后不同的冷却处理方式对混凝土试件的抗压强度产生的的影响。探究了混凝土材料在遭受过火作用后经过喷水冷却方式处理使其自身抗压强度产生改变的内在原因及规律;(5)通过实验所得结果及总结国内外关于过火后的混凝土结构检测鉴定及修复加固方法的研究成果的基础上,建立了可行而又实用的过火后混凝土鉴定方法。总的来说,本文对过火作用后的混凝土性能研究进行了必要的尝试,得出了一些重要的结论及实用的结构鉴定方法,该方法可为今后的实际工程中的运用以及后续的加固与修复工作所采用。
[Abstract]:With the continuous progress of the society and city level, making all kinds of building fire frequency increased rapidly, and a serious threat to people's lives and property safety. At present, the use of all kinds of people's production and life of the building, road and bridge construction, water conservancy construction and various special structure widely used in bearing materials for concrete. Concrete is a kind of multiphase, artificial composite thermal inertia, which is mainly composed of sand and cement as a binder is as coarse aggregate and water according to a certain proportion, with durable good performance, fire resistance performance and overall performance. If the concrete materials for a long time in high temperature environment next, or is suddenly confronted with high temperature, can make significant changes to the physical and chemical properties of concrete materials. Most of the experts and scholars of different after high temperature Research on the performance of concrete, the main consideration is the effect of different temperature effects on which it produces, in addition, different cooling methods, over time, the influence of concrete strength grade of the factors such as the less consideration. For more accurate analysis of concrete at high temperature or after fire the performance, so we need to consider the mechanical properties and temperature of concrete over time, the relationship between the factors of cooling and so on, and the concrete structure evaluation in high temperature or after fire and repair reinforcement work. This paper provides the basis for a number of concrete strength grade after different heating temperature, different. Time and different cooling methods after compressive mechanical properties were carried out experimental research and theoretical analysis of necessity. At the same time, combined with the real Check the results, put forward the feasible concrete structure after fire identification method. The main work of this paper is as follows: (1) a test fire of various types of different strength grade of concrete, the experimental results show that with the continuation of a fire temperature and time of concrete materials suffered, the apparent color produced from shallow to deep changes, in addition, the specimen also appeared in the corners and lack of exfoliation phenomenon more and more serious. At the same time, the physical properties after high temperature in fire or the outer surface of the concrete material, such as surface color, appearance quality damage, reduce variations with temperature and fire time. To calculate the fire temperature roughly by these physical changes, and for the structure of the fire or high temperature after the detection, identification and reinforcement for supporting repair; (2) using the international standard ISO-834 The temperature curves of concrete specimens were burned experiments, and selected different over time, the concrete temperature of specimen are discussed; (3) the influence of different heating temperature, try to change the compressive mechanical properties of different fire time multiple strength grade of concrete with different strength grade this paper given the concrete test set and test temperature based on the temperature and cooling processing, data fitting specimens from relation between the compressive strength of concrete after fire and the fire temperature and time out of use; (4) the test of different cooling treatment after fire the influence of compressive strength of concrete. The concrete materials subjected to fire on after cooling water treatment effect make its compressive strength have changed The internal causes and regularity of change; (5) the results of basic research results obtained by the experiment and summarizes concrete structure testing and repair on the burned reinforcement methods, the identification method establishes a feasible and practical concrete after fire. In general, this paper attempts to study the essential properties of concrete after the fire, some important conclusions are obtained and the structure identification method is practical, this method can be used for practical engineering in the future and the subsequent strengthening and repair work.

【学位授予单位】：华北水利水电大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU528

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