高温对不同钢纤维掺量超高性能混凝土性能及钢纤维拔出机制的影响  

Mechanical Properties and Pull-out Behavior of Steel Fibers of Ultra-High Performance Concrete Exposed to High Temperature

作　　者：韩方玉 吉旭平 刘加平[1] 潘亭宏 赵文昊 汤金辉 沙建芳 刘建忠 HAN Fangyu;JI Xuping;LIU Jiaping;PAN Tinghong;ZHAO Wenhao;TANG Jinhui;SHA Jianfang;LIU Jianzhong(Southeast University,Nanjing,211103,China;Jiangsu Sobute New Materials Co.Ltd.,Nanjing,211103,China;State Key Laboratory of High Performance Civil Engineering Materials,Nanjing,211103,China;Kunming University of Science and Technology,Kunming 650000,China)

机构地区：[1]东南大学材料科学与工程学院,南京211103 [2]江苏苏博特新材料股份有限公司,南京211103 [3]高性能土木工程材料国家重点实验室,南京211103 [4]昆明理工大学建筑工程学院,昆明650000

出　　处：《硅酸盐学报》2024年第11期3565-3571,共7页Journal of The Chinese Ceramic Society

基　　金：国家重点研发计划(2021YFB2601002);江苏省基础研究计划自然科学基金-前沿引领技术基础研究专项(BK20222004);中交科技研发项目(K22096-2);工程咨询项目(8512008540)。

摘　　要：为揭示高温对超高性能混凝土(UHPC)性能及钢纤维拔出机制的演变规律,研究了25~800℃钢纤维对UHPC力学/热工性能的影响规律,并基于纤维拔出以及SEM测试揭示了钢纤维的高温拔出机制。结果表明:钢纤维会提高UHPC的导热系数,但不改变其随温度升高而降低的基本规律,比热容则相反;UHPC的抗压强度和弹性模量随温度升高先增后减,钢纤维可改善其高温残余抗压强度,但对弹性模量影响较小;温度改变钢纤维拔出模式,25~200℃时,钢纤维拔出时表面光滑,UHPC抗拉强度变化不大;400℃时,钢纤维拔出会附带部分基体,UHPC抗拉强度开始显著下降;600℃及以后钢纤维表现为拔断破坏,钢纤维掺量对UHPC抗拉强度影响较小。Introduction Ultra-high performance concrete(UHPC),as an advanced cementitious fiber-reinforced composite material,is often widely used as a load-bearing member in the critical parts of various types of large-span and high-rise structures.However,the increasingly frequent fire disasters have posed a great challenge to the safe serviceability of UHPC.Steel fiber,as an important factor for UHPC to achieve ultra-high toughness,the cracking mechanism of steel fibers exposed to high-temperature will directly affect the high-temperature residual properties of UHPC.Although some scholars have carried out studies on the residual properties of UHPC after high temperature,there are less systematic studies on the influence of steel fibers on the mechanical and thermal properties of UHPC,especially on the deterioration mechanism of steel fibers exposed to high temperature.In view of this,this work systematically investigates the influence of steel fiber on the mechanical and thermal properties of UHPC exposed to high temperature.The mathematical model between steel fiber dosage-temperature-mechanical properties/thermal properties was established.In addition,the changes in the pull-out behavior of steel fibers from the UHPC matrix at different temperatures were investigated for the first time,and the deterioration mechanism of steel fibers exposed to high temperature was elucidated based on SEM tests.Methods The Onoda P.II 52.5 cement and the blending material produced by Jiangsu Sobute New Material Co.were used,respectively.At the same time,an appropriate amount of polypropylene fiber was mixed to reduce the risk of explosive spalling of UHPC.UHPC with 0%,1.0%,2.0%and 2.5%steel fiber volume mixing were prepared.The concrete molding size was 100 mm×100mm×100 mm,and 28 d standard curing was carried out after the casting was completed.Then the mechanical and thermal properties were tested after high temperature.The changes in the pull-out mechanism of steel fibers after high temperature were also investigated.Results and disc

关 键 词：超高性能混凝土 高温 钢纤维 力学性能 热工参数 拔出机制 

分 类 号：TU528[建筑科学—建筑技术科学]