超高性能水泥基复合材料抗多次冲击性能  

Multiple impact resistance of ultra-high performance cement-based composites

作　　者：戎志丹[1,2] 王亚利 孟亚奎 Rong Zhidan;Wang Yali;Meng Yakui(School of Materials Science and Engineering,Southeast University,Nanjing 211189,China;Jiangsu Key Laboratory of Construction Materials,Southeast University,Nanjing 211189,China)

机构地区：[1]东南大学材料科学与工程学院,南京211189 [2]东南大学江苏省土木工程材料重点实验室,南京211189

出　　处：《东南大学学报（自然科学版）》2020年第2期320-326,共7页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51678142);中央高校基本科研业务费专项资金资助项目.

摘　　要：采用大掺量矿物掺合料(35%粉煤灰+10%硅灰+10%偏高岭土)等量取代水泥,与最大粒径2.36 mm的天然砂和2种不同形状(端勾型与平直型)的超细镀铜钢纤维,制备出超高性能水泥基复合材料(UHPCC).通过分离式霍普金森压杆装置对UHPCC进行高速冲击压缩实验,研究了应变率、冲击次数、纤维种类及掺量对该材料抗多次冲击性能的影响规律,同时采用X-ray CT扫描测试技术,揭示了UHPCC的动态损伤变化规律及其抗多次冲击机理.结果表明,在钢纤维掺量不超过3%时,UHPCC抗冲击的能力随纤维掺量的增加而不断提高;动态压缩强度随应变率的提高而相应地增长;端勾型比平直钢纤维增强的UHPCC显示出更为优异的抗多次冲击压缩的性能,其破坏裂纹主要出现在试件的孔洞等薄弱区,破坏程度随冲击次数的增加而加剧,裂缝逐渐从边缘向中部扩展,最后导致试件贯通开裂.Ultra-high performance cement-based composites(UHPCCs) were prepared by substituting cement with a large amount of mineral admixture(35% fly ash+10% silica fume+10% metakaolin), natural sand with a maximum particle size of 2.36 mm and two kinds of ultra-fine copper coated steel fibers with different shapes(end hook type and flat type). The high-speed impact compression experiments of UHPCCs were carried out by using the split Hopkinson pressure bar. The effects of strain rate, number of impacts, types and volume fraction of fiber on the impact resistance of UHPCCs were studied. The results show that when the content of steel fiber is less than 3%, the impact resistance of UHPCCs increases with the increase of the fiber content;the dynamic compressive strength increases with the increase of strain rate;UHPCCs reinforced by end hook type steel fiber show better performance of multiple impact compression resistance than that reinforced by flat steel fiber, and its failure cracks mainly appear in the weak areas, such as holes of the specimen, and the failure degree is higher with the increase of impact times, the cracks gradually expand from the edge to the middle, and finally lead to the through crack of the specimen.

关 键 词：钢纤维 超高性能水泥基复合材料 霍普金森压杆 多次冲击 动态性能 

分 类 号：O346.4[理学—固体力学]