摘要
为研究氯离子干湿循环对带裂缝超高性能混凝土(Ultra High Performance Concrete,UHPC)梁的影响,在UHPC梁中预制弯曲裂缝,浸泡在5.0%的NaCl溶液中进行干湿循环试验,而后测试其力学性能,并取样测定裂缝及其两侧的氯离子和化学结合水含量。结果表明:带裂缝的钢筋UHPC梁经过氯离子干湿循环后,材料内部发生了再水化,构件的抗裂性、极限承载力和刚度均有提升;氯离子在裂缝处沿梁体纵向扩散范围与裂缝宽度、干湿循环时间无关;由于UHPC材料的高致密性,氯离子从裂缝处沿梁体表面的扩散范围及向裂缝深处的扩散范围均低于普通混凝土,带裂缝的UHPC构件具有优良的抗氯离子渗透性能;钢筋UHPC构件的初始裂缝宽度较小时,再水化作用可在一定程度上修复裂缝,但初始裂缝宽度超过0.35 mm时无法修复。
In order to study the effect of chloride ion dry wet cycle on ultra high performance concrete(UHPC)beams with cracks,bending cracks were prefabricated in UHPC beams,soaked in 5.0%NaCl solution for dry wet cycle test,and then their mechanical properties were tested.Samples were taken to determine the chloride ion and chemically bound water content in the cracks and both sides.The results show that after the chloride ion dry wet cycle,the internal rehydration of the cracked reinforced UHPC beams occurs,and the crack resistance,ultimate bearing capacity and stiffness of the members are improved.The longitudinal diffusion range of chloride ions along the beam at the crack has nothing to do with the crack width and dry wet cycle time.Due to the high compactness of UHPC materials,the diffusion range of chloride ions from the crack along the beam surface and to the crack depth is lower than that of ordinary concrete.UHPC members with cracks have excellent chloride ion penetration resistance.When the initial crack width of reinforced UHPC members is small,rehydration can repair the cracks to a certain extent,but when the initial crack width exceeds 0.35 mm,it cannot be repaired.
作者
李文
季城
张音
李志光
余自若
申耀杰
韩冰
LI Wen;JI Cheng;ZHANG Yin;LI Zhiguang;YU Ziruo;SHEN Yaojie;HAN Bing(BCEG Advanced Construction Materials Co.Ltd.,Beijing 102611,China;China Railway Construction Investment Group Corporation Limited,Beijing 100855,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)
出处
《铁道建筑》
北大核心
2022年第9期103-107,共5页
Railway Engineering
基金
中央高校基本科研业务费专项资金(2019JBM089)。
关键词
工程材料
承载力
试验研究
UHPC梁
干湿循环
氯离子
裂缝宽度
engineering materials
bearing capacity
experimental study
UHPC beam
dry wet cycle
chloride ion
crack width
