再生混凝土材料及简支板阻尼性能

Damping Properties of Recycled Aggregate Concrete and Simply-Supported Recycled Aggregate Concrete Slabs

摘要:

采用悬挂、悬臂和简支试验法，研究了再生粗骨料取代率、添加高分子阻尼材料、边界条件以及损伤程度对再生混凝土材料及再生混凝土简支板阻尼性能的影响。研究表明，对于再生混凝土的材料阻尼性能，随着再生粗骨料取代率的增加，再生混凝土的阻尼比呈现增大趋势，再生粗骨料取代率为100%的再生混凝土阻尼比比普通混凝土高30%以上；添加橡胶颗粒能明显提高再生混凝土材料和板在弹性阶段内的阻尼；而添加聚丙烯纤维对弹性阶段的再生混凝土材料阻尼比没有明显影响。对于再生混凝土板，其阻尼比随损伤程度的增加先增大后减小。通过对加载过程中裂缝发展规律的研究，发现再生混凝土板的开裂行为与阻尼测试结果存在相关性，表明因裂缝而产生的界面摩擦阻尼是影响再生混凝土板阻尼的重要因素。

关键词:再生混凝土;阻尼比;阻尼改性材料;损伤

Abstract:

The effects of recycled coarse aggregate(RCA) replacement percentage, polymer damping material, boundary conditions and damage level on the damping properties of recycled aggregate concrete (RAC) material and slabs were studied by using suspension, cantilever, and simply-supported tests. On the material level, the test results show that the damping ratio of RAC increases with the increase of the replacement percentage of RCA. The damping ratio of RAC with 100% replacement of the RCA is increased by 30% compared with the referenced natural aggregate concrete. Adding rubber particles can significantly improve the damping ratio of RAC in the elastic stage. Adding polypropylene fiber has no remarkable effect on the damping ratio of RAC in the elastic stage. On recycled aggregate concrete slabs, it is found that the damping ratios of recycled concrete slabs increase first and then decrease with the increase of the damage degree. The relationship between the cracking behaviors and the change in damping ratios are identified by observing the development of cracks. It shows that the damping ratio of RAC slabs is related to the crack behaviors, thus the interface friction damping caused by the crack is an important factor affecting the damping ratio of RAC slabs.

Key words:recycled concrete;damping ratio;damping modified material;damage