聚丙烯纤维混凝土断裂韧度试验与数值分析  

Experiment and numerical analysis on fracture toughness of polypropylene fiber reinforced concrete

作　　者：许颖 樊悦 王青原 张振宇 XU Ying;FAN Yue;WANG Qing-yuan;ZHANG Zhen-yu(Guangdong Provincial Key Laboratory of Intelligent and Resilient Structures for Civil Engineering,Harbin Institute of Technology,Shenzhen 518055,China)

机构地区：[1]哈尔滨工业大学(深圳)广东省土木工程智能韧性结构重点实验室,广东深圳518055

出　　处：《吉林大学学报（工学版）》2024年第10期2884-2896,共13页Journal of Jilin University:Engineering and Technology Edition

基　　金：国家自然科学基金项目(52078173);广东省自然科学基金项目(2024A1515011980)。

摘　　要：本文采用9组不同配合比的聚丙烯纤维增强混凝土(Polypropylene fiber reinforced concrete,PPFRC)进行预制裂缝梁三点弯曲试验,以聚丙烯纤维掺量和长径比为控制变量,基于双K断裂模型和四阶段断裂模型分别探讨了聚丙烯纤维对混凝土不同断裂韧度的影响,得到了PPFRC的粘聚力-裂缝张开位移双线性软化曲线,引入影响系数解决了经验计算公式的修正问题,利用ABAQUS的扩展有限元法模拟断裂过程,通过参数分析验证模型分析梁断裂行为的可行性。本文结果表明:四阶段断裂模型更适用于作为PPFRC结构失效的判定准则,模型中的宏观裂缝起裂韧度与纤维掺量成正比,与长径比成反比,结构失效韧度与掺量和长径比均呈正相关。掺入12 kg/m^(3)、20 mm长聚丙烯纤维的混凝土宏观裂缝起裂韧度和结构失效韧度分别为9.80、55.32 MPa·m^(1/2)。双线性软化本构经验公式中引入的聚丙烯粗纤维β_(p)=0.849;聚丙烯细纤维β_(p)在0.409~0.552,取值随长径比增大而上升。Nine groups of notched PPFRC beam with different proportions are tested for three-point bending test to study the control variable as polypropylene fiber dosage and length/diameter ratio.Based on double-K fracture model and four-stage fracture model,the influence of polypropylene fiber on different fracture toughness is discussed respectively.The bilinear softening curve of PPFRC is concluded,The influence coefficient is introduced to solve the problem of modifying the empirical calculation formula.The XFEM(Extended finite element method)of ABAQUS was used to simulate the fracture process,and the feasibility of the model was verified by parameter analysis.The results show that the four-stage fracture model is more suitable for judging the failure of PPFRC structure.The macro-crack initiation toughness in the model is positively correlated with the fiber dosage and negatively correlated with the length/diameter ratio.The structural failure toughness is positively correlated with the fiber dosage and length/diameter ratio.The macro crack initiation toughness and structural failure toughness of 12 kg/m^(3) and 20 mm polypropylene fiber concrete are 9.80 MPa·m^(1/2)and 55.32 MPa·m^(1/2).The β_(p) of macro fiber introduced in bilinear softening constitutive equation is 0.849;The value of β_(p) of micro fiber is in the range of 0.409-0.552 and increases with the increase of aspect ratio.

关 键 词：建筑材料 聚丙烯纤维 断裂韧度 扩展有限元法 双线性软化曲线 

分 类 号：TU528[建筑科学—建筑技术科学]