钢纤维掺量对陶粒混凝土梁长期变形的影响规律  

Influence of steel fiber contentto the creep of ceramsiteconcrete beams

作　　者：朱红兵[1,2,3] 吴宇鑫 李秀[4] 夏昌煌 于亚刚 ZHU Hongbing;WU Yuxin;LI Xiu;XIA Changhuang;YU Yagang(School of Urban Construction,Wuhan University of Science and Technology,Wuhan 430065,China;Institute of High Performance Engineering Structure,Wuhan University of Science and Technology,Wuhan 430065,China;Hubei Provincial Engineering Research Center of Urban Regeneration,Wuhan 430065,China;School of Transportation Engineering,Wuhan Technical College of Communications,Wuhan 430065,China)

机构地区：[1]武汉科技大学城市建设学院,湖北武汉430065 [2]武汉科技大学高性能工程结构研究院,湖北武汉430065 [3]城市更新湖北省工程研究中心,湖北武汉430065 [4]武汉交通职业学院交通工程学院,湖北武汉430065

出　　处：《混凝土》2024年第7期58-62,68,共6页Concrete

基　　金：国家自然科学基金(52178182);湖北省高等学校优秀中青年科技创新团队计划项目(T2022002);武汉科技大学湖北省“十四五”优势特色学科(群)基金(2023D0501)。

摘　　要：为探究钢纤维掺量对陶粒混凝土梁徐变的影响规律,通过长期变形观测试验、理论推导式和有限元建模的方法对不同钢纤维掺量的陶粒混凝土梁的徐变性能开展研究。首先,对4种钢纤维掺量的陶粒混凝土梁开展了连续180 d的徐变挠度观测,获得徐变挠度-加载时间关系曲线、钢纤维掺量对徐变挠度的影响规律曲线;随后,参照ACI209徐变系数计算式和ACI435徐变计算式建立了隐含钢纤维掺量的陶粒混凝土梁徐变计算式;最后,按试验梁参数建立了有限元模型。研究结果表明:陶粒混凝土试件梁加载前期徐变增长较快,随着时间推移徐变增长速率逐渐变缓,加载至120 d后趋于稳定;钢纤维掺量对陶粒混凝土梁徐变影响明显,钢纤维掺量低于0.5%,掺加钢纤维对陶粒混凝土梁的徐变值影响小;钢纤维掺量在0.5%~1.0%时,增加钢纤维掺量能有效地较大幅度降低长期荷载作用下的徐变值;但当钢纤维掺量超过1.0%后降低的效果有所减弱;陶粒混凝土梁徐变计算式计算结果与试验实测值吻合较好,能够很好地反映出陶粒混凝土梁的徐变变化规律;有限元模拟进一步验证了钢纤维掺量对陶粒混凝土梁徐变的影响规律和徐变计算式。To explore the influence law of steel fiber content on the creep of ceramsite concrete beams,the creep performance of ceram-site concrete beams with different steel fiber content was studied by means of long-term deformation observation test,theoretical derivation analysis and finite element modeling.Firstly,the creep deflection of ceramsite concrete beams with 4 steel fiber content was observed for 180 days,and the creep deflection loading time relationship curve and the influence law curve of steel fiber content on creep deflection were obtained.Then,referring to ACI209 creep coefficient calculation formula and ACI435 creep calculation formula,the creep calculation formula of ceramsite concrete beam considering steel fiber content was established.Finally,the finite element numerical analysis model was established according to the test beam parameters.The results show that the creep of ceramsite concrete beams increases rapidly in the early stage of loading,and the creep growth rate gradually slows down with the passage of time,and tends to be stable after 120 days of loading.The steel fiber content had a significant impact on the creep of ceramsite concrete beams.The influence of steel fiber content on the creep of ceramsite concrete beams is obvious.When the steel fiber content is less than 0.5%,the influence of steel fiber content on the creep of ceramsite concrete beams is small;In the range of 0.5%to 1.0%,increasing the steel fiber content can effectively reduce the creep value under long-term load.However,when the content of steel fiber exceeds 1.0%,the effect of reduction is weakened.The calculated results of creep formula of ceramsite concrete beam are in good agreement with the measured values,which can well reflect the creep variation law of ceramsite concrete beam.The finite element simulation further verifies the influence law of steel fiber content on the creep of ceramsite concrete beams and the creep calculation formula.

关 键 词：陶粒混凝土梁 钢纤维掺量 徐变 试验 计算式 数值分析 

分 类 号：TU528.01[建筑科学—建筑技术科学]