摘要
通过试验研究了聚丙烯(PP)膜裂纤维体积率和长度对自密实混凝土力学性能(强度、弹性模量和断裂韧性)的影响,结合扫描电镜微观结构分析、Binham流变理论以及断裂力学基本原理分析了纤维对自密实混凝土的工作性和力学性能的影响机理.当PP膜裂纤维的体积率在0.05%—0.15%之间变化,长度在12—15mm时,结果表明,PP膜裂纤维自密实混凝土抗压强度随纤维体积率增加变化不明显,弯拉强度、劈拉强度、弯拉弹性和断裂韧性随纤维体积率增加而逐步增加,抗压弹性模量随纤维体积率增加而减少;PP膜裂纤维自密实混凝土的轴心抗压强度、弯拉强度以及劈拉强度与立方体抗压强度之比分别在0.70—0.73、0.14—0.17和0.08—0.09范围内,轴心抗压强度与立方体抗压强度比值较普通自密实混凝土对比组略有降低,但弯拉强度、劈拉强度与立方体抗压强度之比分别提高17%—42%和14%—29%.当PP膜裂纤维体积率超过0.15%或长度超过15mm,PP膜裂纤维自密实混凝土的强度、弯拉弹性模量及断裂韧性随纤维体积率增加开始出现不同程度的降低.
Mechanical properties of self-compacting concrete （SCC）reinforced with fibrillated polypropylene fiber（FPF） were investigated, which involved three different FPF lengths of 12, 15 and 19mm at four volumes of 0.05% ,0.10% ,0.15% and 0. 20%. Then,the microstructure of SCC reinforced with FPF was observed through scanning electronic microscope （SEM）. The impact mechanism of the fiber on workability and mechanical properties was also analyzed. When the reference mix proportion of SCC was constant, the fiber volume content varied from 0.05% to 0. 15% ,and the fiber length range was 12 or 15mm,the results had shown that：（ 1 ） The workability of the fresh SCC gradually decreased with the increase of the fiber content; （2） The compressive strength of the hardened SCC changes slightly, the compressive Young＇s modulus decreases with the fiber addition, while the flexural tensile strength, splitting strength, flexural Young＇s modulus and fracture toughness increasd with the fiber addition ; （3） The ratios of the axial compressive strength, flexural tensile strength and splitting strength to the cube compressive strength were separately between 0. 70-0. 73 , 0. 14-0. 17 and 0. 08-0. 09 ; （4） Comparing to those ratios in the reference SCC, the first ratio mentioned decreased slightly, while the latter two ratios increase separately by 17%-42% and 14%-29%. When the volume content of FPF was more than 0.15%, or the fiber length was more than 15mm, the strength, Young＇s modulus and fracture toughness of the hardened SCC begin to decrease with the fiber addition.
出处
《应用基础与工程科学学报》
EI
CSCD
北大核心
2014年第3期501-511,共11页
Journal of Basic Science and Engineering
基金
国家重点基础研究发展计划(973)项目(2012CB723305)
重庆市基础与前沿研究计划项目(cstc2013jcyjA30011)
交通土建工程材料国家地方联合工程实验室开放基金资助项目(LHSYS-2012-002)
关键词
自密实混凝土
聚丙烯膜裂纤维
工作性
强度
断裂韧性
self-compacting concrete
fibrillated polypropylene fiber
workability
strength
fracture toughness
