Experimental study on the bond performance of deformed steel bar in ultrahigh performance concrete

Ultrahigh performance concrete (UHPC) has emerged as a relatively new material showing excellent ductility compared to normal concrete, and it has the potential to be used in combination with steel bars in several engineering application scenarios. The interfacial bond performance is the key to dete...

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Main Authors: Heng Liu, Yanhai Liu, Aijun Li, Haidong Lei
Format: Article
Language:English
Published: Elsevier 2023-07-01
Series:Case Studies in Construction Materials
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2214509523000530
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author Heng Liu
Yanhai Liu
Aijun Li
Haidong Lei
author_facet Heng Liu
Yanhai Liu
Aijun Li
Haidong Lei
author_sort Heng Liu
collection DOAJ
description Ultrahigh performance concrete (UHPC) has emerged as a relatively new material showing excellent ductility compared to normal concrete, and it has the potential to be used in combination with steel bars in several engineering application scenarios. The interfacial bond performance is the key to determining the effectiveness of force transfer between different materials, which is required to achieve a refined analysis of member behaviour. In this study, central unidirectional pull-out tests of 54 prismatic specimens with deformed steel bars embedded in UHPC were carried out without lateral constraints. The sizes of the specimens included two types: design size and standard size (200 mm × 200 mm × 200 mm). The design size was related to different combinations between anchorage lengths (2, 3, and 4 times the diameter) and concrete covers (2, 3, and 4 times the diameter) of steel bars, which were also the primary variables of this test. Eighteen standard specimens were used to explore the strain change law along the anchorage length of the steel bar. The specimen was loaded according to the displacement control of 1 mm/min on the static tensile loading system, and a linear variable displacement transducer (LVDT) was arranged on both sides of the loading end and the free end of the specimen to collect data continuously. The strain distribution, anchorage lengths, concrete covers, critical anchorage length, maximum bond stress and bond stressslip model of deformed steel bars in UHPC were all thoroughly investigated. Generally, the results revealed that when the anchorage length exceeded two times the diameter of the steel bar, the maximum strain appeared at approximately 1.5 times the diameter away from the loading end. The maximum bond stress decreased with increasing anchorage length, and the maximum reduction was approximately 54.42%, but this law did not apply to the concrete cover. The maximum bond stress increased with increasing concrete cover, and the gain in peak load was approximately 18.23%. However, the excessive concrete cover did not bring a noticeable gain effect. In addition, compared with several existing bond stressslip models, the improved model proposed in this study was in good agreement with the experimental results, and the determination coefficient of related parameters was basically above 0.95.
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spelling doaj.art-d18a913addef4d1881795681c7b485082023-06-21T06:53:35ZengElsevierCase Studies in Construction Materials2214-50952023-07-0118e01874Experimental study on the bond performance of deformed steel bar in ultrahigh performance concreteHeng Liu0Yanhai Liu1Aijun Li2Haidong Lei3School of Railway Engineering, Hunan Technical College of Railway High-Speed, Hengyang 421002, China; School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, ChinaSchool of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, ChinaSchool of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China; Corresponding author.School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, ChinaUltrahigh performance concrete (UHPC) has emerged as a relatively new material showing excellent ductility compared to normal concrete, and it has the potential to be used in combination with steel bars in several engineering application scenarios. The interfacial bond performance is the key to determining the effectiveness of force transfer between different materials, which is required to achieve a refined analysis of member behaviour. In this study, central unidirectional pull-out tests of 54 prismatic specimens with deformed steel bars embedded in UHPC were carried out without lateral constraints. The sizes of the specimens included two types: design size and standard size (200 mm × 200 mm × 200 mm). The design size was related to different combinations between anchorage lengths (2, 3, and 4 times the diameter) and concrete covers (2, 3, and 4 times the diameter) of steel bars, which were also the primary variables of this test. Eighteen standard specimens were used to explore the strain change law along the anchorage length of the steel bar. The specimen was loaded according to the displacement control of 1 mm/min on the static tensile loading system, and a linear variable displacement transducer (LVDT) was arranged on both sides of the loading end and the free end of the specimen to collect data continuously. The strain distribution, anchorage lengths, concrete covers, critical anchorage length, maximum bond stress and bond stressslip model of deformed steel bars in UHPC were all thoroughly investigated. Generally, the results revealed that when the anchorage length exceeded two times the diameter of the steel bar, the maximum strain appeared at approximately 1.5 times the diameter away from the loading end. The maximum bond stress decreased with increasing anchorage length, and the maximum reduction was approximately 54.42%, but this law did not apply to the concrete cover. The maximum bond stress increased with increasing concrete cover, and the gain in peak load was approximately 18.23%. However, the excessive concrete cover did not bring a noticeable gain effect. In addition, compared with several existing bond stressslip models, the improved model proposed in this study was in good agreement with the experimental results, and the determination coefficient of related parameters was basically above 0.95.http://www.sciencedirect.com/science/article/pii/S2214509523000530Ultrahigh performance concrete (UHPC)Deformed steel barBond stress testBond performanceBond stress-slip model
spellingShingle Heng Liu
Yanhai Liu
Aijun Li
Haidong Lei
Experimental study on the bond performance of deformed steel bar in ultrahigh performance concrete
Case Studies in Construction Materials
Ultrahigh performance concrete (UHPC)
Deformed steel bar
Bond stress test
Bond performance
Bond stress-slip model
title Experimental study on the bond performance of deformed steel bar in ultrahigh performance concrete
title_full Experimental study on the bond performance of deformed steel bar in ultrahigh performance concrete
title_fullStr Experimental study on the bond performance of deformed steel bar in ultrahigh performance concrete
title_full_unstemmed Experimental study on the bond performance of deformed steel bar in ultrahigh performance concrete
title_short Experimental study on the bond performance of deformed steel bar in ultrahigh performance concrete
title_sort experimental study on the bond performance of deformed steel bar in ultrahigh performance concrete
topic Ultrahigh performance concrete (UHPC)
Deformed steel bar
Bond stress test
Bond performance
Bond stress-slip model
url http://www.sciencedirect.com/science/article/pii/S2214509523000530
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AT yanhailiu experimentalstudyonthebondperformanceofdeformedsteelbarinultrahighperformanceconcrete
AT aijunli experimentalstudyonthebondperformanceofdeformedsteelbarinultrahighperformanceconcrete
AT haidonglei experimentalstudyonthebondperformanceofdeformedsteelbarinultrahighperformanceconcrete