摘要
为研究3D打印混凝土弯曲疲劳性能,通过216根3D打印试件弯曲疲劳试验,分析不同钢纤维体积率ρ_(f)和纤维长度l_f对构件弯拉强度和弯曲疲劳性能的影响规律,基于双参数Weibull分布理论推导不同失效概率下的疲劳寿命计算公式,提出不同失效概率下的疲劳方程lg S=lg a-b lg N,并进一步分析钢纤维ρ_(f)l_(f)/d_(f)对构件疲劳性能的影响规律。研究结果表明:3D打印混凝土构件疲劳破坏实际是钢纤维发挥阻裂作用的过程,在裂缝产生、扩展、收缩、再扩展、再收缩直至破坏的过程中,裂缝的宽度、长度和深度一直在发生变化,从宏观角度是材料强度和弹性模量不断下降的过程,而微观角度是材料内部组织结构不断劣化的过程。3D打印构件中掺入的钢纤维能够有效阻止横向裂缝的产生和扩展,显著提升混凝土构件的抗弯拉强度、阻裂能力和耐疲劳性能,使其破坏形式由突然脆性破坏过渡为具有韧性的塑性破坏。钢纤维ρ_(f)l_(f)/d_(f)是影响构件抗弯拉疲劳性能的重要因素,在相同的应力比S=0.65作用下,钢纤维ρ_(f)l_(f)/d_(f)由0增至0.60时,构件疲劳次数N提高了252%;相同的疲劳次数N=10^(6)作用下,钢纤维ρ_(f)l_(f)/d_(f)由0增至0.60时,应力比提高了9.15%。3D打印混凝土试件中,钢纤维体积率ρ_(f)比钢纤维长度l_f对疲劳性能的影响程度更明显。研究结果为进一步推动3D打印技术在道路、桥梁等基础设施领域的应用,促进交通行业智能化、工业化发展具有重要意义。
To explore the fatigue performance of 3D printed concrete,2163D printed specimens were subjected to bending fatigue tests,and the effects of different volume ratiosρf and lengths lf of steel fibers on the bending tensile strength and fatigue performance of the components were analyzed.Based on the two-parameter Weibull distribution theory,fatigue life calculation formulas were derived for different failure probabilities.The fatigue equations for different failure probabilities were proposed,and the influence of steel fibers parameters on the fatigue performance of components was further analyzed.The research results show that the fatigue failure process in 3D printed concrete components involves the crack resistance effect of steel fibers.During the process of crack generation,expansion,contraction,re-expansion,and re-contraction,the width,length,and depth of the crack constantly change.Microscopically,it involves continuous deterioration of the material's internal structure.The incorporation of steel fibers into 3D printed specimens can effectively prevent the generation and expansion of transverse cracks,significantly improving the flexural tensile strength,crack resistance and shrinkage limiting ability,and fatigue resistance of concrete components and transitioning their failure mode from sudden brittle failure to ductile plastic failure.The parameterρflf/df of steel fiber is an important factor affecting the flexural tensile strength and fatigue resistance of components.The fatigue number of the component increased by 252%when theρflf/df increased from 0 to 0.60 under the same stress ratio S=0.65,and the stress ratio increased by 9.15%when theρflf/df increases from 0 to 0.60 under the same fatigue number N=106.The research results are of great significance for further promoting the applications of 3D printing technology in the transportation field,promoting industry intelligence,and industrial development.
作者
杜仕朝
康春霞
邬晓光
刘仲洋
DU Shizhao;KANG Chunxia;WU Xiaoguang;LIU Zhongyang(Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China;Research Institute of Highway,Ministry of Transport,Beijing 100088,China;School of Economics and Management,Hebei University of Architecture,Zhangjiakou 715000,China;Shanxi Provincial Major Laboratory for Highway Bridge&Tunnel,Chang’an University,Xi’an 710064,China;School of Civil Engineering,Hebei University of Architecture,Zhangjiakou 715000,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2024年第8期3237-3247,共11页
Journal of Railway Science and Engineering
基金
国家自然科学基金资助项目(52178300)
交通运输部应用基础研究项目(2014319223070)。
