火灾（高温）后绿色高性能纤维增强水泥基复合材料新型结构的地震损伤机理研究

The prospect of the green high-performance fiber-reinforced cementitious composites (GHPFRCC) application in the civil engineering field is promising. But the seismic damage mechanism of the GHPFRCC after fire (high temperature) is a serious problem to be solved. .Firstly, the residual mechanical properties (including the strength, stress-strain curve, deflection and stiffness, etc) and the residual bond strength of the GHPFRCC after fire (high temperature) are exzamed in the experimental investgation, and the damage mechanism of the GHPFRCC after fire (high temperature) is analyzed also by such microstructure analysis methods as scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP). .Secondly, the low cyclic loading tests of the full-scale GHPFRCC column member and a frame with two spans and two stories after fire (high temperature) are performed. The seismic behaviors (including the damage characteristic, deformation, stiffness, hysteresis loop, skeleton curve and load bearing capacity, etc) of the GHPFRCC member and frame structure after fire (high temperature) are studied. .Finally, a nonlinear finite element computation model of the GHPFRCC structure after fire (high temperature) is proposed based on the above experiments results and the GHPFRCC design theory. The redistribution of internal force and seismic damage mechanism of the GHPFRCC structure after fire (high temperature) are revealed through lots of numerical simulations with multi-parameter and multi-work condition (including the fire factors, loading factors, steel reinforcements factors and member size factors, etc). And then the simplified calculation equations and design methods are put forward. .The research achievements enrich the theoretical system of the fiber reinforced cementitious composites in the fire field, and supply the theoretical references for the application of the GHPFRCC structure.

绿色高性能纤维增强水泥基复合材料（GHPFRCC）在土木工程领域极具应用前景，但其火灾（高温）后的地震损伤机理亟需探明。首先，进行火灾（高温）后GHPFRCC材料的力学试验和粘结-滑移试验，并应用扫描电镜（SEM）、压汞测孔法（MIP）等技术手段从微观角度探索GHPFRCC高温损伤机理；其次，进行火灾（高温）后GHPFRCC足尺柱构件和两层两跨框架结构的低周反复载荷试验，探明该类构件和结构火灾（高温）后的抗震性能；最后，基于试验结果和GHPFRCC设计理论，提出GHPFRCC新型结构非线性有限元计算模型，构建火灾（高温）后该新型结构抗震性能的高效计算平台，进行多参数多工况数值计算，揭示GHPFRCC新型结构内力重分布规律和地震损伤机理，并提出简化计算公式和具体设计建议。所取得成果将丰富纤维增强水泥基复合材料火灾安全领域的理论体系，为GHPFRCC新型结构的工程实践提供理论依据和指导原则。

绿色高性能纤维增强水泥基复合材料（Green high-performance fiber-reinforced cementitious composites, 简称GHPFRCC）具有显著的非线性变形和优异的韧性，但其火灾（高温）后的抗震性能的影响因素及规律尚不清楚。本项目以火灾（高温）后GHPFRCC 新型结构的地震损伤机理为研究核心，以理论分析、试验研究和数值计算等为研究手段，从材料、构件及结构等层次系统开展火灾（高温）后GHPFRCC 新型结构的抗震性能影响因素及规律的研究。. 进行了火灾（高温）后GHPFRCC材料层次力学试验、热工参数测试及微观分析等手段探明火灾（高温）后 GHPFRCC 材料的力学性能劣化机理。探明了配合比、受火温度等因素对GHPFRCC 火灾（高温）后的力学性能（如单轴抗压性能、抗压破坏模式、本构关系曲线、弹性模量、三轴抗压性能、直接拉伸性能及抗弯性能等）及热工性能（如热传导率、比热容、质量损失等）的影响规律，总体而言，除了200℃时GHPFRCC抗压强度与常温相比略有增加外，其他力学性能参数和热工性能参数随温度升高大体呈降低趋势，并确定拟合数学关系式。. 明确了配合比、受火温度、冷却方式、钢筋类型、钢筋直径及锚固长度等因素对火灾（高温）后GHPFRCC 与钢筋粘结-滑移性能的影响规律，探索了高温后GHPFRCC 与钢筋之间粘结性能劣化机理，建立了火灾（高温）后GHPFRCC 与钢筋之间粘结滑移本构关系模型，随着温度的升高，粘结强度呈线性降低，淋水冷却会加剧粘结强度的丧失，在400℃后粘结强度降低19-30%，600℃后降低15-25%，800℃后降低37-55%。变形钢筋相对表现出了优异的粘结性能。粘结强度随钢筋直径和锚固长度减小。. 通过拟静力试验等手段探明了火灾（高温）后GHPFRCC 框架梁柱等结构的地震损伤机理，腹筋对于保证GHPFRCC框架梁的火灾安全性是必要的。基于ABAQUS平台进行了多参数、多工况的GHPFRCC 结构的有限元计算，提出了火灾（高温）后GHPFRCC新型结构抗震性能的简化计算方法和设计建议。取得的研究成果为探索该新型结构的火灾安全、抗震性能及相应技术标准提供相应的理论依据，丰富了GHPFRCC 火灾安全领域的理论体系。