含砖粒再生混凝土悬臂梁阻尼性能试验与分析

Test and Analysis of Damping Performance of Recycled Concrete Cantilever Beam Containing Brick Particles

采用悬臂梁自由振动衰减法研究含砖粒再生粗骨料取代率、水胶比、粉煤灰掺量和试件尺寸对含砖粒再生混凝土弹性阶段阻尼性能的影响规律。结果表明:含砖粒再生混凝土阻尼比随含砖粒再生粗骨料取代率的增加而增加,当含砖粒再生粗骨料取代率为100%时,阻尼比随水胶比和粉煤灰掺量的增加而增加;含砖粒再生混凝土较普通混凝土对振动加速度响应衰减更为敏感;试件尺寸对含砖粒再生混凝土阻尼比的影响较小。建立了含砖粒再生混凝土阻尼比与抗压强度的关系计算式。随着取代率的增加,试件超声波波速逐渐降低,且超声波波速与阻尼比相关性较好。最后,给出了考虑含砖粒再生粗骨料取代率的再生混凝土阻尼比与超声波波速的回归方程。

Using the free vibration attenuation method of cantilever beam,the influence of replacement ratio of recycled coarse aggregate containing brick particles,water binder ratio,fly ash content,and specimen size on the damping performance of recycled concrete with brick particles(RCBP)in elastic stage were studied in experiment.The results show that the damping ratio of RCBP increases with the increase of replacement rate of RCBP coarse aggregate.When the replacement rate of RCBP coarse aggregate is 100%,the damping ratio increases with the increase of water binder ratio and fly ash content.RCBP is more sensitive to vibration acceleration response attenuation than regular concrete.The size of specimen has little effect on the damping ratio of RCBP.In addition,the relationship between damping ratio and compressive strength of RCBP was established.With the increase of the substitution rate,the ultrasonic wave velocity gradually decrease,and the ultrasonic wave velocity has a good correlation with the damping ratio.At last,the regression equation between damping ratio and ultrasonic wave velocity of recycled concrete considering the replacement rate of RCBP coarse aggregate is established.