摘要
为研究冻融循环下橡胶混凝土的动态力学特性,采用非金属超声波检测仪测量橡胶体积掺量为10%的混凝土试件在不同冻融循环次数下的纵波波速,并利用直径74 mm变截面分离式霍普金森压杆(SHPB)试验装置在不同冲击气压(0.3,0.4,0.5,0.6 MPa)下对不同冻融循环次数(0、25、50、75、100、125)的橡胶混凝土试件进行单轴冲击压缩试验,分析其应力-应变曲线、峰值应力、极限应变、动态强度增强因子(DIF)和吸能效果变化规律。结果表明:橡胶的掺入使混凝土强度降低,但其韧性及吸能效果明显增加;随着冻融循环次数的增加,橡胶混凝土纵波波速随之减小,损伤度增加,冻融作用对橡胶混凝土造成损伤,降低试件纵波波速;相同冻融循环次数下,随着应变率的增大试件峰值应力、极限应变、DIF和吸收能都随之增大,试件存在明显的应变率效应;0.6 MPa冲击气压下冻融循环25,50,75,100,125次试件峰值应力分别降低了25.1%、37.1%、46%、52.5%、54.8%,随着冻融循环次数的增加,试件峰值应力降低,降幅逐渐减小,循环次数超过100次后试件应力降幅不再明显,极限应变增加,吸收能减少,冻融环境使橡胶混凝土材料的强度和整体性显著降低。
In order to study the dynamic mechanical properties of rubber concrete under freeze-thaw cycles,the longitudinal wave velocity of rubber concrete specimens with 10%rubber volume was measured by non-metallic ultrasonic detector,the impact compression tests of rubber concrete specimens with different freeze-thaw cycles(0,25,50,75,100,125)were carried out by using the 74 mm diameter variable cross-section split Hopkinson compression bar test device under different impact air pressures(0.3,0.4,0.5,0.6 MPa),and the change laws of stress-strain curve,peak stress,ultimate strain dynamic intensity enhancement factor(DIF)and energy absorption effect were analyzed.The results showed that the strength of concrete decreased with the addition of rubber,but its toughness and energy absorption effect increased obviously.With the increase of freeze-thaw cycles,the longitudinal wave velocity of rubber concrete decreased and the damage degree increased.Freeze-thaw action would damage rubber concrete and reduce the longitudinal wave velocity of specimens.Under the same freeze-thaw cycles,with the increase of strain rate,the peak stress,limit strain,DIF and absorbed energy of specimen increased,and there was an obvious strain rate effect.Under the pressure of 0.6 MPa,the peak stresses of 25,50,75,100 and 125 freeze-thaw cycles were reduced by 25.1%,37.1%,46%,52.5%and 54.8%,respectively.With the increase of the number of freeze-thaw cycles,the peak stress of specimens decreased and the decreasing amplitude decreased gradually.After the number of cycles exceeded 100,the decreasing amplitude of stress of specimens was no longer obvious.The ultimate strain increased and the absorbed energy decreased.The freeze-thaw environment significantly reduced the strength and integrity of rubber concrete materials.
作者
龙一飞
潘婵
郭晓琴
李扬薇
LONG Yifei;PAN Chan;GUO Xiaoqin;LI Yangwei(Wuhan City College Urban Construction Department,Wuhan 430083,China)
出处
《工业建筑》
CSCD
北大核心
2022年第4期163-170,139,共9页
Industrial Construction
基金
“十四五”湖北省高等学校优势特色学科(群)(鄂教研函【2021】5号)
武汉城市学院科研项目(2017CYYBKY001)。
关键词
橡胶混凝土
冻融循环
纵波波速
损伤度
动态力学特性
吸收能
rubber concrete
freeze-thaw cycle
longitudinal wave velocity
damage degree
dynamic mechanical properties
absorbed energy
