摘要
为了研究落石冲击荷载作用下高延性混凝土(HDC)板的抗冲击性能,对纤维掺量为0.5%、1.0%、2.0%的6块HDC板和2块普通钢筋混凝土(RC)板进行14 m高度下的落锤冲击试验,对比分析了HDC板和普通钢筋混凝土板抗冲击性能的差异以及不同纤维掺量对HDC板抗冲击性能的影响。采用高速摄像机记录了各试件的试验过程,详细分析了试件的破坏形态,冲击中心最大位移及落锤最大冲击力和冲量。结果表明:在相同的冲击荷载下,普通钢筋混凝土板被击穿,板底喷出大量混凝土碎块,破坏面整齐光滑,裂缝宽且呈十字形,钢筋未屈服,属于局部贯通破坏;HDC板产生数条由中心向四周逐步开展的裂缝,呈放射状分布,板底有少量混凝土碎块剥落,由于HDC与钢筋之间具有很好的粘结能力,钢筋屈服甚至拉断,但是整体裂而不散。落锤直接冲击RC板最小瞬时加速度为933.01 g,最大冲击力914.35 kN,最大冲击时间0.0218 s,大应变率数量级达到1011 s-1。反观HDC板落锤直接冲击板的最小瞬时加速度较RC减小28.1%,最大冲击力减小28.1%,最大冲击时间延长0.006 s,大应变率数量级减小106 s-1。HDC的各项参数对比均明显优于RC。表明HDC板具有良好的抗冲击性能,且纤维体积掺量为1.0%的HDC抗冲击能力最强。
In order to study the rockfall impact resistance of High Ductile Concrete(HDC)slabs under impact load,the hammer drop test was conducted from 14m height and include 6 blocks of HDC slabs and 2 Regular Concrete(RC)slabs.The fiber contents of HDC are 0.5%,1%and 2%.The difference of impact resistance between HDC and RC and the effects of different fiber content on the impact resistance of the HDC slabs were analyzed.The test process of each specimen was recorded by high speed camera.The destruction form of the specimen,the maximum displacement of the impact center and the maximum impact and impulse of the drop Hammer were analyzed.The results show that under the same impact load,the regular concrete slabs are penetrated.The bottom of the slabs are sprayed with a large amount of concrete fragments.The damage surface is neat and smooth.The crack is wide and in cross shape,and the steel bar does not yield,which belongs to local through destruction.The HDC slabs produces several cracks that are gradually developed from the center,and show radiation-like distribution.The bottom of the slab has a small amount of concrete debris spalling.Due to the HDC and steel bar have good bonding capacity,the steel bar yields or breaks eventually,while the whole slabs only crack but not break.The minimum instantaneous acceleration of the falling hammer directly impacting on the RC plate is 933.01 g,maximum impact force 914.35 kN,maximum impact time 0.0278 s,the large strain rate reaches the order of 1011 s-1.In contrast,the minimum instantaneous acceleration of drop hammer impacting on the HDC board is 28.1%less than that of RC board,maximum impact force reduced by 28.1%,maximum impact time extended by 0.006 s,large strain rate reduced by 106 s-1.The results indicate that the HDC slab has good impact resistance performance,and the HDC of fiber volume content 1%has the strongest impact resistance.
作者
寇佳亮
王华丞
KOU Jialiang;WANG Huacheng(School of Civil Engineering&Architecture,Xi'an University of Technology,Xi'an 710048,China;State Key Laboratory of Eco-hydraulics in Northwest Arid Region,Xi'an University of Technology,Xi'an 710048,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2020年第11期239-247,279,共10页
Journal of Vibration and Shock
基金
国家自然科学基金资助项目(51408487)
中国住建部科学技术资助项目(2014-K2-037)
中国博士后科学基金第56批面上资助项目(2014M562437)
陕西省博士后科学基金资助项目
西安理工大学科学研究计划资助项目(118-211403)。
关键词
高延性混凝土板
落锤试验
抗落石冲击性能
纤维含量
破坏形态
high ductile concrete slabs
hammer drop test
rockfall impact resistance
fiber content
destruction
