PVA纤维-纳米SiO2对混凝土抗疲劳性能的影响及机理分析  

Effect of PVA Fiber Mixed with Nano-SiO 2 on FatigueResistance of Concrete and Its Microscopic Mechanism

作　　者：孔政宇 逯静洲[1] 王建伟 王维良 韩文宇 肖瑛 KONG Zheng-yu;LU Jing-zhou;WANG Jian-wei;WANG Wei-liang;HAN Wen-yu;XIAO Ying(School of Civil Engineering,Yantai University,Yantai 264005,China)

机构地区：[1]烟台大学土木工程学院,山东烟台264005

出　　处：《长江科学院院报》2023年第9期170-175,180,共7页Journal of Changjiang River Scientific Research Institute

基　　金：国家自然科学基金项目(51978596);山东省自然科学基金博士基金项目(ZR2017BEE046)。

摘　　要：为研究PVA纤维和纳米SiO2的掺入对混凝土抗疲劳性能的影响,设计了单掺PVA纤维(P组)、单掺纳米SiO2(S组)和混掺PVA纤维与纳米SiO2(SP组)3组试件,对其展开疲劳后的单轴压缩试验,以经历疲劳荷载后混凝土试件的相对动弹性模量和抗压强度,作为分析评价不同掺料方式对混凝土疲劳性能影响的评价指标,并利用SEM电镜扫描试验研究了掺合料的微观作用机理。结果表明:3组混凝土较普通混凝土在抗疲劳性能上都有明显的提升,S组在提高混凝土强度方面表现最为明显;而SP组能够更有效地抑制混凝土内部劣化损伤的发展。从作用机理上来讲,PVA纤维是通过提高混凝土各单元间的抗拉能力,有效降低了混凝土在疲劳荷载作用下的损伤破坏,相当于延长了混凝土的破坏过程;而纳米SiO2则是通过参与反应生成C-S-H(水化硅酸钙)凝胶填充混凝土薄弱区,提高了混凝土的抗压强度,相当于提高了混凝土在疲劳荷载作用下的破坏起点。研究成果对混凝土结构抗疲劳设计有参考价值。This paper presents an experiment aimed at investigating the influence of blending PVA fiber and nano-SiO 2 on the fatigue resistance of concrete.The experimental specimens are divided into three groups:blending PVA fiber only(Group P),nano-SiO 2 only(Group S),and PVA fiber mixed with nano-SiO 2(Group SP).Uniaxial compression tests were performed on the specimens subjected to multiple-cycle fatigue loading,and the resulting data were used to assess their fatigue resistance.The relative dymanic elastic modulus and compressive strength of specimens after the tests were taken as the assessment indices.Additionally,SEM was employed to observe and analyze the microscopic action mechanism.The findings reveal that all three concrete groups exhibit a notable improvement in fatigue resistance compared to ordinary concrete,although the manner of improvement differs.Group S demonstrates the most notable enhancement in concrete strength,while group SP effectively suppresses the development of internal degradation in concrete.In terms of the underlying mechanisms,PVA fibers enhance the tensile capacity between concrete elements,effectively reducing damage and failure under fatigue loads,thereby prolonging the concrete’s failure process.Nano SiO 2 participates in the reaction to generate C-S-H(calcium silicate hydrate)gel,filling the weak areas of the concrete and improving its compressive strength,thus raising the starting point of failure under fatigue loads.These findings provide valuable insights for the design of fatigue-resistant concrete structures.

关 键 词：PVA纤维-纳米SiO2混凝土 抗疲劳性能 扫描电镜(SEM) 微观机理 

分 类 号：TU528.572[建筑科学—建筑技术科学]