基于CT和NMR技术的UHPC孔隙结构研究  

Study on Pore Structure of UHPC Based on CT and NMR Techniques

作　　者：王张翔 金浪 陈培鑫 陈飞翔[2] 姚天豫 陈徐东[1] WANG Zhangxiang;JIN Lang;CHEN Peixin;CHEN Feixiang;YAO Tianyu;CHEN Xudong(School of Civil Engineering and Transportation,Hohai University,Nanjing 210098,China;CCCC Second Harbor Engineering Company Ltd.,Wuhan 430040,China;China Railway 14th Bureau Group Corporation Limited,Jinan 250101,China)

机构地区：[1]河海大学土木与交通学院,南京210098 [2]中交第二航务工程局有限公司,武汉430040 [3]中铁十四局集团有限公司,济南250101

出　　处：《材料导报》2025年第5期155-160,共6页Materials Reports

基　　金：国家自然科学基金(52379124);国家重点研发计划(2021YFB2600200)。

摘　　要：为研究喷射工艺对超高性能混凝土(UHPC)内部孔隙结构的影响,设计了喷射和模筑两种构筑方式的UHPC,利用CT扫描技术进行图像三维重建可视化分析,通过分水岭算法和搜索锥算法建立孔隙网络模型和纤维分布模型,分析了喷射UHPC内部孔隙均匀性分布、微米级孔径分布和纤维分布;借助核磁共振(NMR)技术,通过T_(2)图谱孔径转换,从更为细观的层次研究了喷射UHPC内部的孔径分布情况,并将试验结果与CT扫描结果进行对比分析。结果表明,两种浇筑方式的UHPC内部均以不连通孔隙为主,喷射UHPC内部孔隙均匀性分布有一定降低,其内部的孔径分布趋向于小而密;喷射回弹会造成UHPC内部不同程度的孔隙率增加,其中约1.5%为无害孔,仅约0.2%为有害的非毛细孔;喷射工艺对UHPC内部纤维分布也有影响,喷射UHPC内部纤维绕Z轴(喷射方向)分布得更加均匀,且趋向平行于受喷面呈二维乱象分布。In order to study the effect of spraying process on the pore structure of ultra-high performance concrete(UHPC),the UHPC with two con-struction modes of spraying and molding was designed.The uniformity of the pore distribution,micrometer-level pore size distribution and fi-ber distribution in sprayed UHPC were analyzed through three-dimensional reconstruction and visualization analysis of images used computerized tomography(CT),and the pore network model and fiber distribution model constructed by means of the watershed algorithm and search-cone al-gorithm,respectively.Furthermore,nuclear magnetic resonance(NMR)technology was employed to study the pore size distribution of sprayed UHPC at a finer scale,and the T_(2) spectrum was used to obtain the pore size distribution.The results show that both molding and spraying UHPC have a main distribution of non-connected pores.The uniformity of the pore distribution in sprayed UHPC decreases,and its pore size distribution tends to be small and dense.Spraying rebound causes different degrees of increase in the porosity of UHPC,among which about 1.5%are harmless pores and only about 0.2%are non-capillary harmful pores.The spraying process also affects the fiber distribution in UHPC,and the fi-bers in sprayed UHPC distribute more evenly along the Z-axis(the spraying direction),and tend to be parallel to the sprayed surface in a two-di-mensional chaotic distribution.

关 键 词：喷射UHPC CT 核磁共振 孔径分布 纤维分布 孔隙均匀性 

分 类 号：TU528.53[建筑科学—建筑技术科学]