超高韧性纤维混凝土材料及其功能梯度结构疲劳性能研究
发布时间：2020-12-28 05:09
超高韧性纤维混凝土材料（UHTCC）是一种具有显著应变硬化和多缝开裂特征的水泥基材料,其拉伸应变通常能到达数个百分点,该类材料基于微观力学原理设计制备。作为一种具有高韧性和高耐久性的新型水泥基材料,UHTCC在需要承受反复循环荷载的结构中具有广阔的应用前景。现代基础设施的建设和发展对混凝土结构在长期荷载和交变环境作用下的服役寿命提出了更高要求。因此,对于UHTCC在循环荷载作用下的抗疲劳性能研究具有重要性和迫切性。本文开展了 UHTCC及其功能梯度结构的疲劳性能研究,具体内容如下:1.研究了不同应力水平条件下UHTCC的压缩疲劳性能;建立了考虑应力水平效应的材料疲劳失效变形概率模型;在疲劳损伤失效过程中,发现微裂纹在疲劳源区萌生,在疲劳过渡区扩展,最终在裂缝扩展区形成主裂纹,并发现了三种疲劳导致的纤维失效模式。2.研究了荷载频率对UHTCC压缩疲劳性能的影响;发现UHTCC的疲劳寿命和变形受到荷载频率的影响;揭示了第二阶段应变率、基于循环数的第二阶段应变率和疲劳寿命之间的量化关系,提出了可用于疲劳寿命预测的系列公式;建立了考虑频率效应的疲劳失效应变概率模型。3.提出了基于Weibull...
【文章来源】：浙江大学浙江省 211工程院校 985工程院校 教育部直属院校
【文章页数】：240 页
【学位级别】：博士
【文章目录】：
ACKNOWLEDGEMENTS
致谢
ABSTRACT
摘要
CHAPTER 1 INTRODUCTION
1.1 Background
1.2 Ultra-High Toughness Cementitious Composite （UHTCC）
1.2.1 Mechanical Properties of UHTCC
1.2.2 Durability of UHTCC
1.2.3 Practical Application Cases of UHTCC
1.3 Review on Fatigue Behavior of Fiber-Reinforced Concrete and UHTCC
1.3.1 Fatigue Behavior of Fiber-Reinforced Concrete
1.3.2 Fatigue Behavior of UHTCC
1.4 Research Objectives and Thesis Outline
1.4.1 Research Motivation and Objectives
1.4.2 Thesis Outline
References
CHAPTER 2 COMPRESSIVE FATIGUE BEHAVIOR OF UHTCC
2.1 Introduction
2.2 Experimental Program
2.2.1 Specimen Preparation
2.2.2 Testing Methods
2.3 Fatigue Life and Distribution
2.4 Cyclic Creep Curve
2.5 Secondary Strain Rate
2.6 Comparison of Monotonic and Fatigue Deformation
2.7 Probabilistic Model of Fatigue Failure Strain
2.8 Fatigue Damage Mechanism
2.8.1 Fatigue Failure Mode of Specimen
2.8.2 Static and Fatigue Failure Surface
2.8.3 SEM Analysis
2.8.4 Discussion of the Static and Fatigue Damage Process
2.9 Fatigue-induced Fiber Failure Mechanism
2.9.1 Results of XCT Test
2.9.2 SEM Test and Fiber Failure Mechanism
2.10 Conclusions
References
CHAPTER 3 FREQUENCY EFFECT ON THE FATIGUE BEHAVIOR OF UHTCC
3.1 Introduction
3.2 Material and Testing Method
3.3 Fatigue Life
3.4 Fiber Failure Modes
3.5 Fatigue Deformation
3.6 Secondary Strain Rate
3.7 Probabilistic Model of Failure Strain
3.8 Conclusions
References
CHAPTER 4 FATIGUE DEFORMATION MODEL OF PLAIN AND FIBER-REINFORCED CONCRETE
4.1 Introduction
4.2 Fatigue Deformation Model Based on Weibull Function
4.2.1 Three-Stage Fatigue Deformation and Cumulative Distribution Function
4.2.2 Weibull Function
4.2.3 Fatigue Deformation Model
4.2.4 Model Sensitivity to Its Parameters
4.2.5 Model Application
4.3 Model Validation
4.4 Analysis of Model Parameters
4.4.1 Model Parameters of UHTCC
4.4.2 Model Parameters of Plain Concrete
4.4.3 Discussion
4.5 Deformation-based Method for Fatigue Life Prediction
4.6 Conclusion
References
CHAPTER 5 TENSILE FATIGUE BEHAVIOR OF UHTCC
5.1 Introduction
5.2 Experimental Program
5.3 Crack Pattern
5.4 Fatigue Deformation
5.5 Failure Surface
5.6 Microscopic Investigation
5.7 Fatigue Life and P-S-N Models
5.7.1 Distribution of Tensile Strength and Fatigue Life
5.7.2 P-S-N Models
5.7.3 Comparison of Fatigue Lives
5.8 Conclusion
References
CHAPTER 6 STATIC AND FATIGUE BEHAVIORS OF UHTCC FUNCTIONALLY-GRADED STRUCTURES
6.1 Introduction
6.2 Assembled Participating Permanent Formwork Using UHTCC
6.2.1 Design of UHTCC Permanent Formwork
6.2.2 Fabrication of Reinforced Concrete Member Using UHTCC Permanent Formwork for Bending Test
6.2.3 Test Results and Optimization of the Assembled Permanent Formwork
6.3 Reinforced Participating Permanent Formwork Using UHTCC
6.3.1 Design of Reinforced UHTCC Permanent Formwork
6.3.2 Preparation of Beam Specimens Using Reinforced UHTCC Permanent Formwork
6.3.3 Testing Methods and Results
6.3.4 Strain Profiles and Stiffness of Beam Specimens
6.3.5 Analysis of Failure Process of Beam Specimens Based on Digital Image Correlation（DIC）
6.3.6 Theoretical Analysis and Optimization of the Formwork Design
6.3.7 Manufacturing Tolerance
6.4 Fatigue Behavior of UHTCC Functionally-graded Beam
6.4.1 Experimental Program
6.4.2 Results of Static Tests
6.4.3 Fatigue Life of Reinforced Concrete Beams with UHTCC Layer
6.4.4 Mid-span Deflection and Cracking Modes under Fatigue Loading
6.4.5 Strain Profiles of Beam Specimens
6.4.6 Strain Range of Longitudinal Bar and UHTCC
6.4.7 Fatigue Degradation of UHTCC Layer
6.4.8 Fatigue Strength of Longitudinal Bar
6.4.9 Fatigue Enhancement Mechanism of UHTCC Layer
6.5 Conclusions
References
CHAPTER 7 CONCLUSIONS AND RECOMMENDATIONS
7.1 Concluding Remarks
7.2 Scientific Contributions and Research Impacts
7.3 Recommendations for Future Work
CURRICULUM VITAE AND PUBLICATIONS
本文编号：2943177
【文章来源】：浙江大学浙江省 211工程院校 985工程院校 教育部直属院校
【文章页数】：240 页
【学位级别】：博士
【文章目录】：
ACKNOWLEDGEMENTS
致谢
ABSTRACT
摘要
CHAPTER 1 INTRODUCTION
1.1 Background
1.2 Ultra-High Toughness Cementitious Composite （UHTCC）
1.2.1 Mechanical Properties of UHTCC
1.2.2 Durability of UHTCC
1.2.3 Practical Application Cases of UHTCC
1.3 Review on Fatigue Behavior of Fiber-Reinforced Concrete and UHTCC
1.3.1 Fatigue Behavior of Fiber-Reinforced Concrete
1.3.2 Fatigue Behavior of UHTCC
1.4 Research Objectives and Thesis Outline
1.4.1 Research Motivation and Objectives
1.4.2 Thesis Outline
References
CHAPTER 2 COMPRESSIVE FATIGUE BEHAVIOR OF UHTCC
2.1 Introduction
2.2 Experimental Program
2.2.1 Specimen Preparation
2.2.2 Testing Methods
2.3 Fatigue Life and Distribution
2.4 Cyclic Creep Curve
2.5 Secondary Strain Rate
2.6 Comparison of Monotonic and Fatigue Deformation
2.7 Probabilistic Model of Fatigue Failure Strain
2.8 Fatigue Damage Mechanism
2.8.1 Fatigue Failure Mode of Specimen
2.8.2 Static and Fatigue Failure Surface
2.8.3 SEM Analysis
2.8.4 Discussion of the Static and Fatigue Damage Process
2.9 Fatigue-induced Fiber Failure Mechanism
2.9.1 Results of XCT Test
2.9.2 SEM Test and Fiber Failure Mechanism
2.10 Conclusions
References
CHAPTER 3 FREQUENCY EFFECT ON THE FATIGUE BEHAVIOR OF UHTCC
3.1 Introduction
3.2 Material and Testing Method
3.3 Fatigue Life
3.4 Fiber Failure Modes
3.5 Fatigue Deformation
3.6 Secondary Strain Rate
3.7 Probabilistic Model of Failure Strain
3.8 Conclusions
References
CHAPTER 4 FATIGUE DEFORMATION MODEL OF PLAIN AND FIBER-REINFORCED CONCRETE
4.1 Introduction
4.2 Fatigue Deformation Model Based on Weibull Function
4.2.1 Three-Stage Fatigue Deformation and Cumulative Distribution Function
4.2.2 Weibull Function
4.2.3 Fatigue Deformation Model
4.2.4 Model Sensitivity to Its Parameters
4.2.5 Model Application
4.3 Model Validation
4.4 Analysis of Model Parameters
4.4.1 Model Parameters of UHTCC
4.4.2 Model Parameters of Plain Concrete
4.4.3 Discussion
4.5 Deformation-based Method for Fatigue Life Prediction
4.6 Conclusion
References
CHAPTER 5 TENSILE FATIGUE BEHAVIOR OF UHTCC
5.1 Introduction
5.2 Experimental Program
5.3 Crack Pattern
5.4 Fatigue Deformation
5.5 Failure Surface
5.6 Microscopic Investigation
5.7 Fatigue Life and P-S-N Models
5.7.1 Distribution of Tensile Strength and Fatigue Life
5.7.2 P-S-N Models
5.7.3 Comparison of Fatigue Lives
5.8 Conclusion
References
CHAPTER 6 STATIC AND FATIGUE BEHAVIORS OF UHTCC FUNCTIONALLY-GRADED STRUCTURES
6.1 Introduction
6.2 Assembled Participating Permanent Formwork Using UHTCC
6.2.1 Design of UHTCC Permanent Formwork
6.2.2 Fabrication of Reinforced Concrete Member Using UHTCC Permanent Formwork for Bending Test
6.2.3 Test Results and Optimization of the Assembled Permanent Formwork
6.3 Reinforced Participating Permanent Formwork Using UHTCC
6.3.1 Design of Reinforced UHTCC Permanent Formwork
6.3.2 Preparation of Beam Specimens Using Reinforced UHTCC Permanent Formwork
6.3.3 Testing Methods and Results
6.3.4 Strain Profiles and Stiffness of Beam Specimens
6.3.5 Analysis of Failure Process of Beam Specimens Based on Digital Image Correlation（DIC）
6.3.6 Theoretical Analysis and Optimization of the Formwork Design
6.3.7 Manufacturing Tolerance
6.4 Fatigue Behavior of UHTCC Functionally-graded Beam
6.4.1 Experimental Program
6.4.2 Results of Static Tests
6.4.3 Fatigue Life of Reinforced Concrete Beams with UHTCC Layer
6.4.4 Mid-span Deflection and Cracking Modes under Fatigue Loading
6.4.5 Strain Profiles of Beam Specimens
6.4.6 Strain Range of Longitudinal Bar and UHTCC
6.4.7 Fatigue Degradation of UHTCC Layer
6.4.8 Fatigue Strength of Longitudinal Bar
6.4.9 Fatigue Enhancement Mechanism of UHTCC Layer
6.5 Conclusions
References
CHAPTER 7 CONCLUSIONS AND RECOMMENDATIONS
7.1 Concluding Remarks
7.2 Scientific Contributions and Research Impacts
7.3 Recommendations for Future Work
CURRICULUM VITAE AND PUBLICATIONS
本文编号：2943177
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