高温后钢与再生混凝土界面粘结传力机理及损伤评价

Steel and recycled concrete composite structure has a series of advantages such as strong bearing capacity, excellent seismic behavior, energy conservation,environmental protection, sustainable develepment, and so on. It has very good application prospect.Fire is a high frequency disaster. Study the fire behavior and post fire disaster assessment method of Steel and recycled concrete composite structure is necessary. Reveal the interface bonding mechanism of steel and recycled concrete after high temperature, establish its bond damage model and the bond-slip constitutive equation, all of this are the safety assessment theoretical foundation after fire disaster of steel and recycled concrete combined structure, it have very important theoretical significance and engineering application value. . This item will carry out series intensification of experimental research. First reveal the material mechanical performance of recycled concrete and steel after high temperature. And then to finish simulate fire disater test of three types typical steel and recycled concrete composite components (steel reinforced recycled concrete, recycled concrete filled circle steel tube, recycled concrete filled square steel tube). The high temperature specimen was used two different ways to cool (natural cooling and water cooling).Specimens after cooling were carried out monotonous and reversed loading to test the interface bond distribution and slip performance between steel and recycled concrete. Based on the experimetal data, the influence of different vary parameters to the bond-slip behavior were in-depth analyzed,such as cooling method, loading type, recycled aggregate replacement ratio, high temperature, fire time, concrete strength, steel embedment length, layer thickness, steel confine coefficient, section size and so on. At last, the high temperature bond strength damage model and bond-slip constitutive equation were put forward. All of this can be help for etablishing safety assessment theory and finite element simulation analysis method of steel and recycled concrete composite structure after fire disaster.

钢与再生混凝土组合结构具有承载力高、抗震性能好、节能环保、资源可再生利用等优点，具有很好的应用前景。火灾是高频灾种，开展再生混凝土组合结构火灾后评估研究十分必要。研究建立高温后钢与再生混凝土粘结损伤模型、粘结滑移本构方程，具有重要的理论意义和工程价值。申报课题首先揭示高温后再生混凝土以及钢材自身的性能退化规律，接着对三种典型组合构件（型钢、圆钢管和方钢管再生混凝土组合构件）进行高温试验，采用两种方式进行降温（自然冷却和模拟消防灭火浇水冷却），对降温后的试件进行单调和反复荷载试验，测试型钢/钢管与再生混凝土界面粘结力分布、滑移性能，并深入分析冷却方法、荷载类型、取代率、温度、受火时间、混凝土强度、埋置长度、保护层厚度、钢管套箍系数、截面尺寸等变化参数对粘结滑移性能的影响；提出高温后再生混凝土组合构件粘结强度损伤模型和粘结滑移本构方程，为再生混凝土组合结构灾后安全评估理论奠定基础。

通过850个试件的系统试验，揭示了火灾后钢与再生混凝土界面黏结传力损伤机理。试验类型包括历经不同火灾高温后、不同冷却方式（自然冷却和消防喷水冷却）不同再生骨料类型再生混凝土（再生碎石类和再生卵石类）、圆钢管再生混凝土柱构件、方钢管再生混凝土柱构件、型钢再生混凝土梁柱构件、钢筋再生混凝土梁柱构件。测试内容包括上述各类构件的黏结滑移、轴心受压、偏心受压、受弯以及受剪等各种力学性能指标。获取了大量的宝贵的试验数据库，为建立理论分析模型奠定基础数据；利用有限元软件进行了大量的扩展参数分析，推导建立了火灾高温后不同冷却方式各种再生混凝土构件的极限承载力和刚度计算方法，提出基于回弹法检测和表观现象的灾后评估理论。项目研究共发表期刊论文46篇，其中SCI收录国际期刊论文18篇、国内一级学报EI收录期刊论文13篇、国内中文核心期刊15篇，培养硕士12人。