玄武岩纤维混凝土静力学特性及破裂机制  

Static characteristics and fracture mechanism of basalt fiber reinforced concrete

作　　者：高硕 商玉洁 周喻[2] GAO Shuo;SHANG Yujie;ZHOU Yu(Power China Road Bridge Group Co.,Ltd.,Beijing 100048,China;China School of Civil and Resources Engineering,University of Science and Technology,Beijing 100083,China)

机构地区：[1]中电建路桥集团有限公司,北京100048 [2]北京科技大学金属矿山高效开采与安全教育部重点实验室,北京100083

出　　处：《混凝土》2024年第11期93-99,共7页Concrete

基　　金：国家重点研发计划(SQ2023YFC3700099);中央高校基本科研业务费(FRF-IDRY-GD22-005)。

摘　　要：为研究玄武岩纤维混凝土力学特性及破裂机制,以不同砂率及不同纤维掺量为主要研究变量,开展一系列单轴压缩试验,通过观察其破坏模式及裂纹形式,分析了砂率和纤维掺量对混凝土力学性能及破裂机制的影响效应。同时结合电镜技术对材料的内部结构进行微观表征。颗粒流数值模拟技术(PFC)再现了材料在单轴压缩下的破坏过程,进一步揭示了其破坏规律。研究结果表明:(1)单轴抗压强度随砂率的增加而增大,随纤维掺量的增加呈现出先增大后减小的趋势,加入玄武岩纤维缓解卸载阶段应力下降速率,提高了混凝土延性变形能力;(2)玄武岩纤维的存在降低了裂纹尖端的应力强度因子,从而达到了一定的阻裂效果。但随着砂率的增加,这种抑制效果会有所降低;(3)随着纤维掺量的增加,纤维在内部出现“抱团”现象,影响材料的抗压强度,但加强了阻裂性能;(4)数值模拟表明微裂纹多围绕粗骨料发生,在粗骨料分布集中部位微裂纹更加密集。研究成果可为玄武岩纤维混凝土材料在建筑工程领域应用上提供理论指导。In order to study the mechanical properties and fracture mechanism of basalt fiber reinforced concrete,a series of uniaxial compression experiments were carried out with different sand ratios and different fiber contents as the main research variables.Effects on the mechanical properties and fracture mechanism of concrete.At the same time,the microscopic characterization of the internal structure of the material was carried out by combining CT scanning and electron microscopy techniques.The particle flow numerical simulation technology(PFC)reproduces the failure process of the material under uniaxial compression,and further reveals its failure law.The research results show that:(1)The uniaxial compressive strength of basalt fiber reinforced concrete increases with the increase of sand ratio,and shows a trend of first increase and then decrease with the increase of fiber content.The ductile deformation ability of concrete is improved;(2)The existence of basalt fiber reduces the stress intensity factor at the crack tip,thereby achieving a certain crack resistance effect.However,with the increase of sand ratio,this inhibitory effect will decrease;(3)With the increase of fiber content,the fiber appears“clumping”phenomenon inside,which affects the compressive strength of the material,but can resist cracking;(4)Numerical simulation shows that the microcracks mostly occur around the coarse aggregate,and the microcracks are more dense in the concentrated distribution of the coarse aggregate.The research results can provide theoretical guidance for the application of basalt fiber reinforced concrete materials in the field of construction engineering.

关 键 词：玄武岩纤维混凝土 砂率 裂纹 电镜扫描 PFC颗粒流 

分 类 号：TU528.572[建筑科学—建筑技术科学]