陶粒混凝土-高强混凝土复合叠浇粘结滑移机理及设计研究

The superiority of different types of concrete materials can be effectively elaborated in Heterogeneous overlapped composite (HOC) RC members. The synthetic properties such as the loading/deforming capability, thermal insulation, seismic resistance and fire prevention can be fully elaborated in HOC-RC.Research is carried out aiming at the overlapped-pouring of ceramsite aggregate concrete and high-strength normal concrete. First, influencing factors and variation mechanism on the micro/meso structure characteristic and basic performance of overlapped layer are analyzed, including the change regulation of tangential shear strength, normal tensile performance and bonding-slip of the overlapped layer; Considering the bonding-slip mechanism and characteristics, Analysis of the disposing mode for the overlapped layer on the loading capacity, coincident performing of HOC-RC is conducted; The design and analyzing method of ceramsite lightweight concrete and high-strength normal concrete HOC-RC is developed. At last, Multi-scale finite element modeling and simulating of HOC-RC considering the bonding-slip performance of the overlapped layer are formulated. It brings to the bonding-slip mechanism, influence factors and change regulation when ceramsite aggregate concrete and high-strength normal concrete are overlapped and poured together. The developed theoretical and numerical approaches can provide scientific guidance for the analysis and application of HOC-RC structural members when concrete materials with a certain degree of performance difference are overlapped and poured together.

复合混凝土叠浇构件可以充分发挥不同类型混凝土材料的各自性能优势，在解决工程技术新难题的同时，能有效提高结构构件的受力变形、保温隔热、抗震防火等综合性能。本项目针对陶粒混凝土与高强普通混凝土复合叠浇时系列相关问题展开试验与研究：首先基于浆体材料凝固过程原理及微/细观结构特征对叠浇层结构的影响因素及变化机理进行测试分析，以及叠浇界面层切向剪切强度、法向抗拉强度等宏观粘结性能的变化规律；考虑叠浇层粘结滑移性能，研究叠浇界面处理方式、界面结构特征对叠浇构件整体协调工作性能、变形及承载力的影响分析，并建立复合叠浇构件计算模型与分析计算方法；最后，考虑叠浇界面结构特征及粘结滑移性能建立复合叠浇构件的多尺度有限元模型及分析。项目研究可揭示陶粒混凝土与高强普通混凝土复合叠浇时，叠浇界面的粘结滑移机理、变化规律及影响因素，为具有一定性能差异的混凝土复合叠浇构件的研究与应用提供科学的理论指导依据。

作为一种典型非均质多相复合材料，混凝土材料的劣化损伤一直是备受关注的关键问题，尤其是在混凝土叠合构件及装配式结构中。陶粒轻骨料混凝土（LWAC）具有较高的强重比（强度/容重）、良好的耐久性能、保温隔热性能和抗渗抗震性能，以及兼顾绿色环保等优良特性。与普通高强混凝土的复合叠浇可充分发挥陶粒轻骨料混凝土与普通混凝土各自材料性能优势，一定程度上可改善水泥基材料功能单一、抗拉强度低、韧性差等问题，提高混凝土在复杂特殊工程环境中的适用性，有效改进结构各方面综合性能。.本项目围绕陶粒混凝土与普通混凝土叠合浇筑时结合面的粘结滑移及损伤机理问题，综合试验、数值模拟和理论分析，考虑结合面薄弱区域在法向应力、材料强度等级匹配、复合面处理工艺方式、叠合浇筑间隔时间等主要因素变化下界面剪切强度的变化影响，并建立相关粘结剪切损伤模型。项目主要研究内容包括：关于陶粒混凝土与普通（高强）混凝土叠合浇筑结合面粘结剪切强度的多因素正交试验分析；陶粒混凝土与普通（高强）混凝土叠合面的多尺度有限元模拟分析；陶粒混凝土与普通（高强）混凝土叠合界面粘结性能破坏机理研究及损伤模型建立；基于GBDT机器学习算法陶粒混凝土与普通（高强）混凝土叠合界面粘结强度的预测分析。.通过项目研究可揭示陶粒混凝土与普通（高强）混凝土复合浇筑时，叠合界面的粘结滑移机理、变化规律及影响因素，从而为具有一定性能差异的混凝土复合叠浇构件的研究应用提供科学的理论指导。