粗骨料UHPC匀质性控制及在大跨度桥梁中的应用研究  

Study on uniformity control of coarse aggregate UHPC and its application in long span bridges

作　　者：王志金 张义 谢恩慧 WANG Zhijin;ZHANG Yi;XIE Enhui(The Fourth Engineering Co.,Ltd.,of CCCC First Highway Engineering Co.,Ltd.,Nanning 530031,China;CCCC Highway Bridges National Engineering Research Centre Co.,Ltd.,Beijing 100120,China)

机构地区：[1]中交一公局第四工程有限公司,广西南宁530031 [2]中交公路长大桥建设国家工程研究中心有限公司,北京100120

出　　处：《混凝土》2023年第2期186-192,共7页Concrete

基　　金：国家重点研发计划(2021YFB370443);中交集团院士专项基金项目(YSZX-03-2020-01-B,YSZX-01-2022-02-B);中国交建科技研发项目(2016-ZJKJ-PTJS05)。

摘　　要：为使粗骨料UHPC生产时不产生钢纤维结团等匀质性不良现象,从原材料和施工工艺两方面开展了研究。其中,辉绿岩粒径在3~8 mm范围内一定程度变化时,对粗骨料UHPC的性能影响并不显著;在719 kg/m^(3)高掺量粗骨料的情况下,尺寸为Ф0.30×20 mm的端钩型钢纤维与Ф0.22×14 mm相比会降低抗压强度,略微增加抗折强度;而尺寸为Ф0.30×25 mm的端钩型钢纤维单掺或与短纤维复掺时均易结团,力学性能均下降。粗骨料UHPC在搅拌站生产时,采用钢纤维与粉体颗粒先干混均匀再加水的搅拌方式易结团,宜选择拌制成浆体后再缓慢加入钢纤维的搅拌方式;粗骨料UHPC在运输过程中,搅拌运输车的旋转状态会严重影响粗骨料UHPC的匀质性,运输时应当严格控制搅拌筒的旋转速度。最后在保证匀质性的前提下,采用标准化的施工工艺进行了预制桥面板的生产。In order to avoid poor homogeneity such as steel fiber agglomeration in the production of coarse aggregate UHPC,it conducts research from two aspects of raw materials and construction technology.Among them,when the particle size of diabase changes to a certain extent within the range of 3~8 mm,the performance of coarse aggregate UHPC is not significantly affected.In the case of 719 kg/m^(3) high content of coarse aggregate,the end hook steel fiber with the size ofФ0.30×20 mm will reduce the compressive strength and slightly increase the flexural strength compared withФ0.22×14 mm,while the end hook steel fiber with the size ofФ0.30×25 mm is easy to agglomerate when mixed alone or mixed with short fibers,and the mechanical properties are reduced.When the coarse aggregate UHPC is produced in the mixing plant,it is easy to agglomerate by mixing the steel fiber and powder particles evenly and then adding water.The mixing method of slowly adding steel fiber after mixing into slurry should be selected.During the transportation of coarse aggregate UHPC,the rotation of the mixer truck will seriously affect the homogeneity of coarse aggregate UHPC,and the rotation speed of the mixing drum should be strictly controlled during transportation.Finally,on the premise of ensuring the homogeneity,the prefabricated bridge deck is produced using standardized construction technology.

关 键 词：粗骨料超高性能混凝土 匀质性 施工工艺 预制桥面板 

分 类 号：TU528.01[建筑科学—建筑技术科学]