混凝土冻融损伤模型研究
发布时间：2018-09-09 10:25
【摘要】：混凝土耐久性是指结构在规定的使用年限内，在各种环境条件作用下，不需要额外的费用加固处理而保持其安全性、正常使用的能力。我国地域辽阔，有相当一部分地区处于寒冷地带，其混凝土结构遭受到不同程度的冻融破坏，严重时冻胀开裂使混凝土结构的承载能力降低。抗冻性是混凝土结构耐久性设计中的一个重要指标，研究混凝土的冻融损伤，对合理选择混凝土类型以及采取适当防治措施，充分发挥材料性能，提高设计水平，降低工程造价具有非常重要的意义。 本文依托湖北省自然科学基金项目(项目批准号2012FFB00607)“高性能水泥基复合材料冻融损伤特性研究”，展开对冻融循环作用下混凝土材料抗冻性能的试验研究，主要内容如下： 1.总结了国内外研究学者对混凝土材料损伤的研究理论以及各种损伤模型，详细分析了混凝土的冻融损伤机理。论文根据混凝土的冻融破坏可以看作是材料的疲劳损伤这一观点，利用Aas-Jakobsen材料疲劳损伤寿命公式建立了混凝土冻融损伤模型，经过分析，混凝土材料参数β越大，其抗冻性越差。 2.对三种强度等级均为C50的自密实混凝土、普通混凝土、轻骨料混凝土试块进行了冻融循环试验，循环次数依次为0、50、100、150、200、250、300次，并且每循环50次进行了质量损失和动弹性模量的测定。 3.论文根据试验结果建立了混凝土质量损失率和冻融循环次数的关系曲线以及相对动弹性模量与冻融循环次数的关系曲线，根据试验现象以及实验数据，分析影响混凝土材料抗冻性的因素。 4.论文根据建立的冻融损伤模型，通过对实验数据进行非线性拟合，得到模型中相关的材料参数β曲线，然后将其代入损伤模型，得到了不同种类混凝土的理论损伤量与冻融循环次数的关系曲线。最后将理论曲线与实际的损伤量进行对比，结果表明，理论分析与实际损伤量基本一致。 5.论文研究结果表明，轻骨料混凝土的抗冻性最强，自密实混凝土的抗冻性最差。这主要是因为在冻融循环试验中，影响混凝土抗冻性的材料参数β会随着循环次数的递增，而不断增大，其中自密实混凝土的材料参数增长速度最快，因此自密实混凝土最先被冻坏。
[Abstract]:The durability of concrete refers to the ability of the structure to maintain its safety and normal use under various environmental conditions without extra expense for reinforcement and treatment within the specified service life. China has a vast territory and a considerable part of the region is in the cold zone. The concrete structure suffers different degrees of freezing and thawing damage. When the frost heaving cracking seriously reduces the bearing capacity of concrete structure. The frost resistance is an important index in the durability design of concrete structure. To study the freeze-thaw damage of concrete, to select the concrete type reasonably and to take appropriate prevention measures, to give full play to the material performance and to improve the design level. It is of great significance to reduce the project cost. Based on Hubei Natural Science Foundation Project (Project Grant No. 2012FFB00607), "study on Freeze-thaw damage characteristics of High-Performance cement Matrix Composites", an experimental study on frost resistance of concrete under freeze-thaw cycle is carried out in this paper. The main contents are as follows: 1. The research theory of concrete material damage and various damage models are summarized, and the mechanism of freeze-thaw damage of concrete is analyzed in detail. According to the view that the freeze-thaw failure of concrete can be regarded as the fatigue damage of material, the model of freeze-thaw damage of concrete is established by using the formula of fatigue damage life of Aas-Jakobsen material. The worse the frost resistance. 2. The freeze-thaw cycle tests were carried out on three specimens of self-compacting concrete, ordinary concrete and lightweight aggregate concrete with C _ (50) strength grade. The number of cycles was 050100150 200250300 times, respectively. The mass loss and dynamic modulus of elasticity were measured 50 times per cycle. According to the test results, the relationship curves between the mass loss rate and the freeze-thaw cycles of concrete and the relative dynamic modulus of elasticity and the number of freeze-thaw cycles are established. According to the experimental phenomena and experimental data, the relationship between the relative dynamic modulus of elasticity and the number of freeze-thaw cycles is established. Analysis of factors affecting frost resistance of concrete materials. 4. According to the freeze-thaw damage model, the material parameter 尾 curve of the model is obtained by nonlinear fitting of the experimental data, and then the damage model is substituted. The relationship between the theoretical damage of different kinds of concrete and the number of freeze-thaw cycles is obtained. Finally, the theoretical curve is compared with the actual damage amount. The results show that the theoretical analysis is basically consistent with the actual damage amount. The results show that the frost resistance of lightweight aggregate concrete is the strongest, and that of self-compacting concrete is the worst. This is mainly because in the freeze-thaw cycle test, the material parameter 尾, which affects the frost resistance of concrete, will increase with the increase of cycle times, among which the material parameter of self-compacting concrete will increase fastest. As a result, self-compacting concrete is the first to be frozen.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU375
本文编号：2232116
[Abstract]:The durability of concrete refers to the ability of the structure to maintain its safety and normal use under various environmental conditions without extra expense for reinforcement and treatment within the specified service life. China has a vast territory and a considerable part of the region is in the cold zone. The concrete structure suffers different degrees of freezing and thawing damage. When the frost heaving cracking seriously reduces the bearing capacity of concrete structure. The frost resistance is an important index in the durability design of concrete structure. To study the freeze-thaw damage of concrete, to select the concrete type reasonably and to take appropriate prevention measures, to give full play to the material performance and to improve the design level. It is of great significance to reduce the project cost. Based on Hubei Natural Science Foundation Project (Project Grant No. 2012FFB00607), "study on Freeze-thaw damage characteristics of High-Performance cement Matrix Composites", an experimental study on frost resistance of concrete under freeze-thaw cycle is carried out in this paper. The main contents are as follows: 1. The research theory of concrete material damage and various damage models are summarized, and the mechanism of freeze-thaw damage of concrete is analyzed in detail. According to the view that the freeze-thaw failure of concrete can be regarded as the fatigue damage of material, the model of freeze-thaw damage of concrete is established by using the formula of fatigue damage life of Aas-Jakobsen material. The worse the frost resistance. 2. The freeze-thaw cycle tests were carried out on three specimens of self-compacting concrete, ordinary concrete and lightweight aggregate concrete with C _ (50) strength grade. The number of cycles was 050100150 200250300 times, respectively. The mass loss and dynamic modulus of elasticity were measured 50 times per cycle. According to the test results, the relationship curves between the mass loss rate and the freeze-thaw cycles of concrete and the relative dynamic modulus of elasticity and the number of freeze-thaw cycles are established. According to the experimental phenomena and experimental data, the relationship between the relative dynamic modulus of elasticity and the number of freeze-thaw cycles is established. Analysis of factors affecting frost resistance of concrete materials. 4. According to the freeze-thaw damage model, the material parameter 尾 curve of the model is obtained by nonlinear fitting of the experimental data, and then the damage model is substituted. The relationship between the theoretical damage of different kinds of concrete and the number of freeze-thaw cycles is obtained. Finally, the theoretical curve is compared with the actual damage amount. The results show that the theoretical analysis is basically consistent with the actual damage amount. The results show that the frost resistance of lightweight aggregate concrete is the strongest, and that of self-compacting concrete is the worst. This is mainly because in the freeze-thaw cycle test, the material parameter 尾, which affects the frost resistance of concrete, will increase with the increase of cycle times, among which the material parameter of self-compacting concrete will increase fastest. As a result, self-compacting concrete is the first to be frozen.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU375
【参考文献】
相关期刊论文 前10条
1 赵永利,孙伟;混凝土材料疲劳损伤方程的建立[J];重庆交通学院学报;1999年01期
2 赵松山;对拟合优度R~2的影响因素分析与评价[J];东北财经大学学报;2003年03期
3 宋玉普,赵国藩;混凝土内时损伤本构模型[J];大连理工大学学报;1990年05期
4 王新杰;马星;;混凝土徐变预测模型的比较分析[J];低温建筑技术;2009年11期
5 杨晓华,姚卫星,段成美;确定性疲劳累积损伤理论进展[J];中国工程科学;2003年04期
6 亢景富,冯乃谦;水工混凝土耐久性问题与水工高性能混凝土[J];混凝土与水泥制品;1997年04期
7 罗昕;卫军;;冻融条件下混凝土损伤演变与强度相关性研究[J];华中科技大学学报(自然科学版);2006年01期
8 于海祥;武建华;李强;;混凝土损伤本构模型研究评述[J];重庆建筑大学学报;2007年02期
9 张峰;李术才;李守凯;;混凝土随机冻融损伤三维预测模型[J];土木建筑与环境工程;2011年01期
10 冀晓东;宋玉普;刘建;;混凝土冻融损伤本构模型研究[J];计算力学学报;2011年03期
相关硕士学位论文 前1条
1 薛明琛;混凝土及其强韧化材料的失效分析[D];山东理工大学;2006年
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