常温养护超高性能混凝土弯拉性能及轴拉本构模型  

Bending-tension performance and axial tension constitutive model ofultra-high performance concrete under normal temperature curing

作　　者：梁林 王秋维[1,2,3] 史庆轩[1,2,3] 韩文超 于婧[1] LIANG Lin;WANG Qiuwei;SHI Qingxuan;HAN Wenchao;YU Jing(College of Civil Engineering,Xi an University of Architecture and Technology,Xi an 710055,Shaanxi,China;State Key Laboratory of Green Building,Xi an University of Architecture and Technology,Xi an 710055,Shaanxi,China;Key Lab of Structural Engineering and Earthquake Resistance,Ministry of Education,Xi an University of Architecture and Technology,Xi an 710055,Shaanxi,China)

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055 [2]西安建筑科技大学绿色建筑全国重点实验室,陕西西安710055 [3]西安建筑科技大学结构工程与抗震教育部重点实验室,陕西西安710055

出　　处：《建筑科学与工程学报》2024年第3期43-53,共11页Journal of Architecture and Civil Engineering

基　　金：国家自然科学基金项目(52178505,51878543);陕西省教育厅协同创新中心项目(23JY043);陕西省自然科学基础研究计划项目(2020JM-487)。

摘　　要：根据水化反应方程和紧密堆积理论确定了常温养护下超高性能混凝土(UHPC)的基础配合比,基于此考虑水胶比和钢纤维掺量设计了8组UHPC抗弯试件。通过四点弯曲试验,分析了试件的受弯破坏形态、荷载-挠度曲线、弯拉特征参数和弯曲韧性等;基于试验结果采用倒推方法得到了UHPC轴拉应力-应变曲线,采用回归分析提出了考虑纤维特征的轴拉本构模型,并经过材料和构件两个层次的验证。结果表明:掺加钢纤维可抑制主裂缝的发展,从而明显改善UHPC的抗弯韧性,钢纤维掺量为2.0%的UHPC弯曲韧性指数达到116.9 J;随着水胶比增大,试件抗折强度和峰值挠度均呈下降趋势;增大钢纤维掺量明显提升了试件弯曲性能,掺入2.0%钢纤维的UHPC与未掺纤维相比,其初裂挠度和抗折强度分别提升157.14%和148.63%;当纤维含量为1.5%~2.0%时,试件具有良好的弯拉性能;水胶比对曲线平台段趋势影响不大,纤维掺量大于1.0%时曲线具有较明显的应变硬化特征,可保证UHPC良好的抗拉性能,其应变硬化特征随着纤维掺量增大而变得更明显;所提模型对UHPC受拉应力-应变关系具有较好的预测性。The basic mix proportion of ultra-high performance concrete(UHPC)under normal temperature curing was determined based on the hydration reaction equation and the compact packing theory.Eight groups of UHPC flexural specimens were designed considering the water-binder ratio and steel fiber content based on the proportion.The bending failure mode,load-deflection curve,bending-tension characteristic parameters,and bending toughness of the specimens were analyzed by four-point bending tests.Based on the test results,the UHPC axial tension stress-strain curve was obtained by using the backward analysis method.The axial tension constitutive model considering fiber characteristics was proposed using regression analysis and validated at both material and component levels.The results show that the addition of steel fibers can suppress the development of main cracks,thereby significantly improve the bending toughness of UHPC.The bending toughness index of UHPC with 2.0%steel fiber content reaches 116.9 J.As the water cement ratio increases,the flexural strength and peak deflection of the specimen both show a decreasing trend.Increasing the steel fiber content can significantly improve the bending performance of the specimens.Compared with the specimens untreated by fibers,the initial crack deflection and flexural strength of UHPC with 2.0%steel fibers increased by 157.14%and 148.63%respectively.When the fiber content is between 1.5%and 2.0%,the specimen exhibits good flexural and tensile properties.The water cement ratio has little effect on the trend of the platform section of the curve.When the fiber content is greater than 1.0%,the curve has obvious strain hardening characteristics,which can ensure the good tensile performance of UHPC.The strain hardening characteristics become more obvious with the increase of fiber content.The proposed model has good predictive ability for the tensile stress-strain relationship of UHPC.

关 键 词：超高性能混凝土 常温养护 弯拉性能 倒推分析方法 轴拉本构模型 

分 类 号：TU528[建筑科学—建筑技术科学]