摘要
钢纤维对UHPC基体的增强增韧作用,受到其材料、形状、尺寸和掺量等因素的影响.本文采用优化设计后的狗骨试件尺寸,以目前应用最多的圆直钢纤维和弓形钢纤维为对象,对UHPC材料进行单轴拉伸试验研究,并与抗折、劈裂强度试验结果进行对比分析;分析在钢纤维体积掺量为2%的情况下,单掺不同形状圆直钢纤维和弓形钢纤维对UHPC基本材料性能的影响,并分析纤维增强系数和长径比之间的关系.掺有钢纤维的试验组,随纤维长径比的增大,应力-应变曲线中的弹性段峰值点增大,硬化段增长,软化段变得平缓,曲线所包围面积也增大.掺弓形钢纤维试验组曲线下降段呈现锯齿形.掺量相同时,圆直长纤维对轴拉强度、极限应变、弹性模量的提高效果明显,短纤维对初裂强度的提高效果明显.弓形钢纤维增强的UHPC,随纤维长径比的增大,其轴拉强度、极限应变、弹性模量和断裂能增强,其初裂强度递减.纤维增强系数和其形状、长径比有关.
The reinforcing and toughening effect of fiber on the ultra-high performance concrete(UHPC)is influenced by its material,shape,size,content and so on.In this study,the optimized design of dog-bones for tensile test of UHPC is used for uniaxial tensile testing,and then compared with bending strength and splitting strength of UHPC with straight fiber and hook-shaped fiber.The tensile properties of UHPC is investigated and the relationship between the fiber reinforced coefficient and length to diameter ratio is analyzed.With the increase of length-diameter ratio of steel fiber,the peak point of elastic segment in the stress-strain curve increases,the hardening segment grows,the softening segment flattens,and the area enclosed by the curve also increases.The descending segment of the curve for the test group with hook-shaped steel fiber exhibits a marked serration.In a certain fiber content,the straight fiber has obvious effects on improving the axial tensile strength,ultimate strain and elastic modulus,while the short fiber has obvious effects on improving the initial crack strength.With the increase of length-diameter ratio of fiber for the UHPC,the axial tensile strength,ultimate strain,elastic modulus and fracture energy of UHPC with hook-shaped fiber increase,while the initial fracture strength decreases.The fiber reinforcement coefficient is related to its shape and length-diameter ratio.
作者
苏家战
林毅焌
陈宝春
黄卿维
Su Jiazhan;Lin Yijun;Chen Baochun;Huang Qingwei(College of Civil Engineering, Fuzhou University, Fuzhou 350116, China;Sustainable and Innovative Bridge Engineering Research Center of Fujian Province University, Fuzhou University, Fuzhou 350116, China)
出处
《宁夏大学学报（自然科学版）》
CAS
2020年第3期246-251,261,共7页
Journal of Ningxia University(Natural Science Edition)
基金
国家重点研发计划项目(2018YFC0705400)。
关键词
超高性能混凝土
抗拉性能
钢纤维
纤维增强系数
长径比
ultra-high performance concrete
tensile property
steel fiber
fiber reinforced coefficient
ratio of length to diameter
