粗骨料UHPC预制桥面板破膜排气振捣工艺试验研究  

Experimental Investigation on Membrane-Breaking and Air-Exhausting Vibration Methods of Reinforced CA-UHPC Deck

作　　者：崔冰[1] 王康康 汪钺宸 邓开来[2] 赵灿晖[2] CUI Bing;WANG Kang-kang;WANG Yue-chen;DENG Kai-lai;ZHAO Can-hui(CCCC Highway Consultants Co.,Ltd.,Beijing 100010,China;Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]中交公路规划设计院有限公司,北京100010 [2]西南交通大学桥梁工程系,四川成都610031

出　　处：《桥梁建设》2022年第6期79-86,共8页Bridge Construction

基　　金：国家自然科学基金项目(52078436)。

摘　　要：为进一步提升粗骨料超高性能混凝土(CA-UHPC)预制桥面板的抗裂能力,排出CA-UHPC预制桥面板在振捣棒振捣后残留的表层气泡,提出扎钉振捣和铺撒碎石振捣2种破膜排气振捣工艺,并设计制作了2组试件进行工艺试验研究。第1组试件共36个,研究高频(200 Hz)振捣棒振捣工艺对CA-UHPC试件气泡分布的影响,确定了顶层破膜深度为4 cm、振捣时间为25 s以及振捣间距为160 mm等基本振捣参数。基于第1组试验结果,设计第2组共9个试件(不同的扎钉振捣次数及碎石覆盖率),通过四点弯曲试验研究2种破膜排气振捣工艺对桥面板表观质量及弯曲力学性能的影响。第2组试件结果表明:扎钉振捣破膜排气工艺可有效穿透试件的表面结膜,辅助平板振捣,可有效排出表层气泡,对试件的麻面弯曲初裂强度影响显著;在前3次扎钉振捣时,桥面板的抗裂性能随着扎钉振捣次数的增加而提高,而超过4次后,试件的麻面弯曲初裂强度降低,建议扎钉振捣次数为3或4次;铺撒碎石虽然可以有效破膜,但会导致弯曲初裂强度降低。根据试验结果,给出了初始缺陷折减以及扎钉振捣次数与构件弯曲初裂强度的相关曲线和计算公式。To improve the crack resistance of the prefabricated bridge deck of coarse aggregate ultra-high performance concrete(CA-UHPC)and remove residual bubbles from the surface of the CA-UHPC prefabricated bridge deck after vibration by vibrating rods,two kinds of membrane-breaking and air-exhausting vibration methods are proposed,including nailing and paving gravels on the surface of deck.Two groups of specimens were designed and manufactured for test investigation.The first group of 36 specimens was prepared to explore the influence of high-frequency vibrating rods(200 Hz)on the bubble distribution of CA-UHPC specimens during vibration process.The basic vibration parameters,including the top layer rupture depth of 4 cm,vibration time of 25 s and vibration intervals of 160 mm,were determined.Based on the results of the first group of tests,a total of 9 specimens(having different nailing vibration times and gravel coverage)in the second group were designed.The effects of two kinds of membrane-breaking and air-exhausting vibration methods on the bending mechanical properties of bridge decks were studied by four-point bending test.The results of the second group of specimens demonstrate that the nailing vibration method allows effective penetration into the surface membrane of the bridge deck.Assisting with the plate vibration,the surface bubbles can be apparently eliminated,and the initial crack strengths of the nailing surfaces of specimens can also be improved significantly.Before the 4 times of nailing vibration,the crack resistance of the bridge deck is improved with the increase of nailing vibration times,and after more than 4 times of nailing vibration,the initial bending strengths of the nailing surfaces of specimens show sign of decreasing.A number of 3 or 4 times of nailing vibration is suggested.Although paving gravels can effectively break the surface membrane,it will lead to the reduction of initial crack strength.Based on the test results,the fitting curves and calculation formulas of the initial defect redu

关 键 词：预制桥面板 粗骨料超高性能混凝土 扎钉振捣 铺撒碎石 破膜排气振捣工艺 弯曲抗裂性能 工艺试验 

分 类 号：U443.32[建筑科学—桥梁与隧道工程] U445.4[交通运输工程—道路与铁道工程]