钢纤维特征参数及成型方式对UHPC轴拉性能的影响  

Influence of Steel Fiber Characteristic Parameters and FormingMethods on Tensile Performance of Ultra-high Performance Concrete

作　　者：邓宗才[1] 王梦新 王宏君 陈相宇 DENG Zong-cai;WANG Meng-xin;WANG Hong-jun;CHEN Xiang-yu(Key Laboratory of Urban and Engineering Safety and Disaster Reduction of Ministry of Education,Beijing University of Technology,Beijing 100124,China;Zhitai Technology New Materials(Jiangsu)Co.,Ltd.,Suzhou 215000,China)

机构地区：[1]北京工业大学城市与工程安全减灾省部共建教育部重点实验室,北京100124 [2]致泰科技新材料(江苏)有限公司,江苏苏州215000

出　　处：《长江科学院院报》2025年第4期177-182,192,共7页Journal of Changjiang River Scientific Research Institute

摘　　要：为探究超高性能混凝土(UHPC)在不同钢纤维下的单轴拉伸力学性能,设计了10组狗骨头型试件单轴拉伸试验,研究了钢纤维长径比(37、50、64、65)、掺率(2%、3%、4%)、形状(端钩型和弧型)和成型方式(搅拌法和渗浆法)对UHPC轴拉强度、应力-应变曲线、拉伸韧性和破坏过程的影响。结果表明:端钩型钢纤维长径比增加,UHPC轴拉强度提高6.54%~9.37%,软化段残余强度比值提高5.00%~38.30%;端钩型钢纤维体积掺率从2%增至3%、4%,UHPC抗拉强度、峰值应变和软化段残余强度比值均有所提高,拉伸韧性增加;端钩型钢纤维渗浆法成型试件相比搅拌法试件,强度变化不大,但峰值应变提高53.61%~91.96%;弧型钢纤维UHPC拉应力-应变曲线具有应变硬化特性,破坏过程呈多裂缝开展;与同长径比端钩型钢纤维试件相比,弧型钢纤维UHPC峰值拉应变提高了19.41~19.96倍,软化段残余强度比值提高18.00%~70.03%,弧型钢纤维增韧效果优于端钩型钢纤维。采用硬化指数和软化段残余强度比值方法可以全面评价UHPC轴拉峰前应变硬化特征和峰后的轴拉韧性。To explore the mechanical properties of ultra-high performance concrete(UHPC)with different steel fibers under uniaxial tension,we designed ten sets of uniaxial tensile tests on dog-bone-shaped UHPC specimens.We investigated how the aspect ratio(37,50,64,65),dosage(2%,3%,4%),shape(end-hooked and curved),and forming methods(mixing and slurry)of steel fibers affect the tensile strength,stress-strain curves,tensile toughness,and failure process of UHPC.Results reveal that as the aspect ratio of hooked steel fiber rises,the tensile strength of UHPC increases by 6.54%-9.37%,and the residual strength ratio in the strain-softening segment grows by 5.00%-38.30%.When the volumetric dosage of end-hooked steel fiber increases from 2%to 3%and 4%,the tensile strength,peak strain,and residual strength ratio in the strain-softening segment of UHPC increase,along with an enhancement in tensile toughness.Compared with specimens formed by the mixing method,those formed by the slurry method with end-hooked steel fibers show no significant change in strength,but the peak strain increases by 53.61%-91.96%.The stress-strain curve of UHPC with curved steel fibers demonstrates strain-hardening characteristics,and its failure process involves the propagation of multiple cracks.In comparison to specimens with end-hooked steel fibers of the same aspect ratio,UHPC with curved steel fibers exhibits a 19.41-19.96-fold increase in peak tensile strain and an 18.00%-70.03%increase in the residual strength ratio in strain-softening segment.This indicates that the toughening effect of curved steel fibers is superior to that of end-hooked steel fibers.By using the hardening index and the residual strength ratio in the strain-softening segment,we can comprehensively evaluate the strain-hardening characteristics before peak axial-tensile strain and the axial-tensile toughness after peak in UHPC.

关 键 词：超高性能混凝土 轴拉性能 钢纤维 特征参数 成型方式 

分 类 号：TU528[建筑科学—建筑技术科学]