配合比参数影响钢纤维-基体界面黏结性能的试验  

Investigation on effect of mixture ratio on interfacial bonding properties of steel fiber-matrix

作　　者：袁明 梁恩 颜东煌 韦炳灯 刘昀 黄练[1] YUAN Ming;LIANG En;YAN Dong-huang;WEI Bing-deng;LIU Yun;HUANG Lian(School of Civil Engineering,Changsha University of Science and Technology,Changsha 410114,Hunan,China;School of Road and Bridge Engineering,Hunan Communication Polytechnic,Changsha 410132,Hunan,China)

机构地区：[1]长沙理工大学土木工程学院,湖南长沙410114 [2]湖南交通职业技术学院路桥工程学院,湖南长沙410132

出　　处：《长安大学学报（自然科学版）》2020年第6期57-66,共10页Journal of Chang’an University(Natural Science Edition)

基　　金：国家重点基础研究发展计划(“九七三”计划)项目(2015CB057706);国家自然科学基金项目(52078054,51678068);湖南省教育厅科学研究项目(18B140);湖南省交通科技项目(201932)。

摘　　要：为研究活性粉末混凝土(RPC)材料中的相关配合比参数对钢纤维-RPC基体界面黏结性能的影响规律,以硅灰、消泡剂和骨料平均粒径3个配合比参数为变量,制作了6组基体进行钢纤维单丝拉拔试验。根据相应评价指标对实测数据和拉拔荷载-滑移曲线特征进行对比分析,并运用微观电子扫描技术(SEM)观测拉拔出的钢纤维表面微观形态、钢纤维拔出后的基体隧洞微观形貌以及基体表面微观形貌,进一步探讨试验参数对钢纤维-RPC基体界面黏结性能的影响。研究结果表明:硅灰对钢纤维-RPC基体界面黏结性能有明显影响,合适的硅灰掺量可以大幅度提升钢纤维-RPC基体的平均黏结强度和等效黏结强度,当硅灰掺量(质量分数,下同)提高到30%,其等效黏结强度相对于20%硅灰掺量有所下降;消泡剂的掺入不仅没有改善钢纤维-RPC基体界面黏结性能,反而产生了不利影响,掺入消泡剂会使基体的平均黏结强度有所提升,但等效黏结强度明显下降;由SEM观测钢纤维拔出后的基体隧洞形貌发现隧洞内存在孔洞缺陷,基体表面的大气泡数量减少而微小气泡增多,并且分布比大气泡更加密集;保持砂胶比一致,骨料平均粒径由0.2 mm增至0.4 mm时,其平均黏结强度和等效黏结强度变化不大,骨料平均粒径在0.2~0.4 mm范围内变化对钢纤维-RPC基体界面黏结性能影响较小。该研究可为深入研究活性粉末混凝土材料的界面性质优化以及其配比提供参考。In order to study the influence of the relevant mix parameters of reactive powder concrete(RPC) materials on the interfacial bonding properties of steel fiber-RPC matrix,six groups of matrix were made for single-sided pullout tested with three mix parameters as variables included silica fume,defoamer and average size of aggregate. According to the corresponding evaluation indexes,the measured data and the characteristics of the pull load-slip curve were compared and analyzed. The micro morphology of the steel fiber surface,the matrix tunnel after fiber was pulled out, the micro morphology of the matrix surface were observed by scanning electron microscope(SEM),and the effect of the test parameters on the interfacial bonding properties of steel fiber-RPC matrix was further discussed. The results show that silica fume has obvious influence on the interfacial bonding properties of steel fiber-RPC matrix. The appropriate content of silica fume can greatly improve the average bond strength and equivalent bond strength of steel fiber-RPC matrix,and the equivalent bond strength is reduced relative to the 20% silica fume content,when the content of silica fume(mass fraction, the same as below) increases to 30%. The addition of defoamer will not improve the interfacial bonding properties of steel fiber-RPC matrix,but has adverse effects. With the addition of defoamer,the average bond strength of the matrix increases,but the equivalent bond strength decreases significantly. The SEM observation of the matrix tunnel after fiber was pulled out shows that there are hole defects in the tunnel,the number of large bubbles on the surface of the matrix decreases,while the number of small bubbles increases,and the distribution of small bubbles is more dense than the large bubbles. Keeping the cement-sand ratio consistent,the average particle size of aggregate increases from 0.2 to 0.4 mm, and the particle size double,but the average bond strength and the equivalent bond strength has little change. The change of the average particle

关 键 词：桥梁工程 活性粉末混凝土 单丝拉拔试验 钢纤维 黏结性能 微观形貌 

分 类 号：U446[建筑科学—桥梁与隧道工程]