CF/SSF增强珊瑚砂水泥砂浆微观结构分析及动态劈裂拉伸试验研究  

Microstructure and dynamic splitting tensile properties of CF/SSF reinforced coral sand cement mortar

作　　者：郭瑞奇 李江南 马林建 欧灿 许鑫 GUO Ruiqi;LI Jiangnan;MA Linjian;OU Can;XU Xin(College of Civil Engineering,Xiangtan University,Xiangtan 411105,Hunan,China;State Key Laboratory of Disaster Prevention and Mitigation of Explosion and Impact,Army Engineering University of PLA,Nanjing 210007,Jiangsu,China)

机构地区：[1]湘潭大学土木工程学院,湖南湘潭411105 [2]陆军工程大学爆炸冲击防灾减灾全国重点实验室,江苏南京210007

出　　处：《爆炸与冲击》2024年第11期75-87,共13页Explosion and Shock Waves

基　　金：湖南省自然科学基金(2023JJ40610,2023JJ30569);湖南省教育厅优秀青年项目(23B0124);湖南省研究生科研创新项目(QL20230162)。

摘　　要：珊瑚混凝土是一种拉压强度严重不对称的材料,研究其动态拉伸力学性能对岛礁防护工程具有重要意义。为了探究碳纤维(carbon fiber,CF)和不锈钢纤维(stainless steel fiber,SSF)增强珊瑚砂水泥砂浆在冲击荷载作用下的∅动态拉伸力学性能,采用100 mm的分离式霍普金森压杆(split Hopkinson pressure bar,SHPB)装置进行动态劈裂试验,对比分析不同纤维掺量的珊瑚砂水泥砂浆在不同应变率下的动态抗拉强度和能量耗散规律,并结合扫描电子显微镜揭示混杂纤维的作用机理。结果表明:复掺CF和SSF的珊瑚砂水泥砂浆试样的静、动态抗拉强度均有显著提高,最大动态抗拉强度增长率为66.03%。在相同应变率下,试样的动态抗拉强度与纤维掺量呈正相关,其破碎程度与纤维掺量呈负相关,纤维的桥接作用对试样裂缝开展具有良好的抑制效果。在同一纤维掺量下,动态增长因子随应变率的升高明显增大,动态增长因子最大值为2.44,表现出明显的拉伸应变率效应。珊瑚砂水泥砂浆试样的破碎程度及耗散能量均与应变率呈正相关,且纤维掺量越高,试样破坏时需要耗散的能量越多。Coral concrete is a material with severely asymmetric tensile and compressive strengths.Therefore,studying the dynamic tensile mechanical properties of coral concrete is of great significance for island reef protective engineering.To investigate the dynamic tensile mechanical properties of carbon fiber(CF)and stainless steel fiber(SSF)reinforced coral sand cement mortar under impact loading,dynamic splitting tests were conducted using a 100 mm diameter split Hopkinson pressure bar(SHPB)device.Comparative analysis was carried out on the dynamic tensile strength and energy dissipation patterns of coral sand cement mortars with different fiber contents at various strain rates.In the SHPB tests,cement mortar specimens with different fiber contents were prepared:no fiber,1.5%CF,1.5%CF with 0.5%SSF,1.5%CF with 1.0%SSF,and 1.5%CF with 1.5%SSF.The specimens were subjected to four impact velocities:3.45,4.86,6.54,and 7.34 m/s.This allowed for impact-splitting tests conducted at different strain-rate ranges.In addition,scanning electron microscope(SEM)tests were performed to reveal the action mechanism of the hybrid fibers.The results indicate that the static and dynamic tensile strengths of CF and SSF-reinforced coral sand cement mortar specimens are significantly improved,with a maximum dynamic tensile strength increase ratio of 66.03%.At the same strain rate,the dynamic tensile strength of the specimens positively correlates with the fiber content,while the fragmentation degree negatively correlates with the fiber content.The fiber bridging effect effectively suppresses the development of cracks in the specimens.Under the same fiber content,the dynamic increase factor increases significantly with the increase of strain rate,with a maximum increase factor of 2.44,demonstrating a clear tensile strain rate effect.The fragmentation degree and dissipated energy of coral sand cement mortar specimens positively correlate with the strain rate,and samples with higher fiber dosages require more energy to dissipate during failure.

关 键 词：珊瑚砂水泥砂浆 混杂纤维 动态劈裂拉伸 应变率效应 能量耗散 

分 类 号：O347.3[理学—固体力学] TU377[理学—力学]