橡胶轻骨料混凝土阻尼性能试验
Experimental on damping capacity of rubber lightweight aggregate concrete

为了定量描述橡胶颗粒对轻集料混凝土阻尼性能的影响规律，以橡胶颗粒替代率为主要参数，自行设计了悬臂梁试件，分析不同龄期时橡胶轻骨料混凝土立方体抗压强度随橡胶颗粒替代率的变化规律。考虑到混凝土在服役过程中普遍存在损伤的实际情况，采用自由衰减法分别测试橡胶轻骨料混凝土悬臂梁在不同橡胶颗粒替代率和不同损伤程度时的基本频率和阻尼比演化规律，分析橡胶颗粒对橡胶轻骨料混凝土阻尼性能的影响规律和作用机理，建立橡胶轻骨料混凝土悬臂梁阻尼比、损伤指数和橡胶颗粒替代率间的相关关系。研究结果表明：随着橡胶颗粒替代率的增大，橡胶轻骨料混凝土立方体抗压强度不断降低；相同损伤程度时，随着橡胶颗粒替代率的增大，橡胶轻骨料混凝土悬臂梁阻尼比不断增大；相同橡胶颗粒替代率时，随着损伤控制位移的增大，橡胶轻骨料混凝土悬臂梁阻尼比先增大后减小，损伤控制位移达到30 mm时，各橡胶颗粒替代率下的橡胶轻骨料混凝土悬臂梁阻尼比均达到最大值；随着位移角增大，橡胶轻骨料混凝土悬臂梁弯曲动刚度损伤指数不断增大；随着损伤指数的增大，不同橡胶颗粒替代率的橡胶轻骨料混凝土阻尼比均呈现先增大后减小趋势，峰值阻尼比对应的损伤指数为0.60~0.75，掺橡胶颗粒试样的峰值阻尼比均大于未掺橡胶颗粒试样。研究成果可为橡胶轻骨料混凝土结构设计及动力性能分析提供理论基础。
In order to quantitatively describe the influence of rubber particles on the damping capacities of lightweight aggregate concrete, cantilever beam specimens were designed by ourselves and the replacement ratio of rubber particles were set as main parameters. The change law of cubic compressive strength of rubber lightweight aggregate concrete with rubber particles replacement rate at different ages were tested. In practice, damage was widely existed in concrete during service process. The evolutionary law of basic frequency and damping ratio of rubber lightweight aggregate concrete cantilever beam at different rubber particles replacement ratio and different damage degree were detected respectively by free decay method. The influence law and mechanism of rubber particles on the damping capacities of rubber lightweight aggregate concrete were analyzed. The relationship between damping ratio, damage index and rubber particles replacement ratio of rubber lightweight aggregate concrete cantilever beam were established. The results show that the compressive strength of rubber lightweight aggregate concrete cube decreases with the increase of the replacement rate of rubber particles. The damping ratio of rubber lightweight aggregate concrete cantilever beam increases with rubber particles replacement ratio at the same damage degree. For the same rubber particles replacement ratio, the damping ratio of rubber lightweight aggregate concrete cantilever beam first increases and then decreases with increase of damage control displacement. When the damage control displacement reaches to 30 mm, the damping ratio of rubber lightweight aggregate concrete cantilever beams at each rubber particles replacement ratio reaches the maximum. The flexural dynamic stiffness damage index of rubber lightweight aggregate concrete cantilever beam augments with the increase of displacement angle. With the increase of damage index, the damping ratio of rubber lightweight aggregate concrete cantilever beam at different rubber