Experimental study on flexural behavior of damaged reinforced concrete (RC) beam strengthened by toughness-improved ultra-high performance concrete (UHPC) layer

Zhang, Yang; Li, Xingliang; Zhu, Yanping; Shao, Xudong

doi:10.1016/j.compositesb.2020.107834

Cited by 113 publications

(36 citation statements)

References 27 publications

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“…The laboratory study was performed in two separate sections. In the first part, the mechanical properties of SFRC are evaluated by considering two variables: the amount of SFs (0, 0.5, 1, 1.5, and 2% of concrete volume) and the strength category of concrete (40,50,and 60 MPa). The experiments are presented in Table 1.…”

Section: The Study Proceduresmentioning

confidence: 99%

“…They showed that installing CFRP sheets can increase the maximum beam load by about 2.13 times. Zhang et al [40] used concrete layers to strengthening RC beams and showed that this method could improve the bearing capacity by about 2.2 times. The present study results also showed that using SPFCJ containing SFs can increase the bearing capacity of beams by about 2.28 times.…”

Section: Comparative Study With Other Studiesmentioning

confidence: 99%

“…The mechanical properties of SFRC are evaluated by considering two variables: the amount of SFs (0, 0.5, 1, 1.5, and 2% of the concrete volume) and the category of concrete (40,50, and 60 MPa). In the second part, the flexural load test of the beams was performed in the strengthening and without strengthening modes.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Strengthening of RC Beams using Steel Plate-Fiber Concrete Composite Jackets (Finite Element Simulation and Experimental Investigation)

Shadmand

Hedayatnasab

Kohnehpooshi

2022

IJE

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In this research, steel plate-fiber concrete composite jackets (SPFCJ) was used to strengthen the RC beams. The accuracy of the analysis method was evaluated by modeling RC beams fabricated in the laboratory, and a good agreement was observed. Variables in the finite element method (FEM) analysis include the strength class of concrete used in the main beam (15,20, and 25 MPa), the beam length (1.4 and 2.8 m), the type of jackets (RC jacket, SPFCJ, and CFRP sheet), and jacket thickness (40, 60 and 80 mm). SPFCJ is effective for all three concrete grades and increased the energy absorption capacity by 1.88, 2.07, and 2.25 times, respectively. The bearing capacity of the strengthened beam with 60 mm composite jackets increased by 79 and 20% more than the values corresponding to jackets with 40 and 80 mm thickness. The jacket thickness parameter significantly influences the response of strengthened beams with the proposed composite jackets. Depending on the dimensions and geometric characteristics of the beam, the appropriate thickness for the jacket should be considered, and increasing the thickness can not always improve the beam bearing capacity.

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Section: The Study Proceduresmentioning

confidence: 99%

Section: Comparative Study With Other Studiesmentioning

confidence: 99%

See 1 more Smart Citation

Strengthening of RC Beams using Steel Plate-Fiber Concrete Composite Jackets (Finite Element Simulation and Experimental Investigation)

Shadmand

Hedayatnasab

Kohnehpooshi

2022

IJE

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“…Ultra-high-performance concrete (UHPC) is a new type of cement-based composite [ 1 ], which is usually composed of cement, silica fume, quartz sand, fiber, superplasticizer, and other components [ 2 ]. UHPC has the characteristics of high strength, high toughness, high ductility [ 3 ], crack resistance [ 4 ], impact resistance [ 5 ], and durability [ 6 ]. Components built with this material have lightweight, strong spanning ability [ 7 , 8 ] and have become a new type of building material with application prospects [ 9 ].…”

Section: Introductionmentioning

confidence: 99%

Interfacial Shear Performance of Epoxy Adhesive Joints of Prefabricated Elements Made of Ultra-High-Performance Concrete

Zhang

Zou

et al. 2022

Polymers

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Application of ultra-high-performance concrete (UHPC) in joints can improve the impact resistance, crack resistance, and durability of structures. In this paper, the direct shear performance of ultra-high-performance concrete (UHPC) adhesive joints was experimentally studied. Twenty-four direct shear loading tests of UHPC adhesive joints were carried out considering different interface types and constraint states. The failure modes and load-slip curves of different interfaces were studied. Results indicated that passive confinement could enhance the strength and ductility of the interface; the average ultimate bearing capacity of the smooth, rough, grooved, and keyway specimens with passive restraint were, respectively, increased by 11.92%, 8.91%, 11.93%, and 17.766% compared with the unrestrained ones. The passive constraint force changes with the loading and finally tends to be stable. The epoxy adhesive has high reliability as a coating for the UHPC interface. The adhesive layer is not cracked before the failure of the specimen, which is also different from the common failure mode of adhesive joints. Failure of all specimens occurred in the UHPC layer, and the convex part of the groove interface shows the UHPC matrix peeling failure; the keyway interface is the shear damage of the key-tooth root, and the rest of the keyway showed UHPC surface peeling failure. According to the failure mode, the shear capacity of UHPC keyway adhesive joints under passive restraint is mainly provided by the shear resistance of key teeth, the friction force of the joint surface, and the bonding force of the UHPC surface. The friction coefficient was determined based on the test results, and the high-precision fitting formula between the shear strength of the UHPC surface and the passive constraint force was established. According to the Mohr stress circle theory, the proposed formula for direct shear strength of UHPC bonded joints under passive constraint was established. The average ratio of the proposed UHPC adhesive joint calculation formula to the test results was 0.99, and the standard deviation was 0.027.

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“…Ultra-High Performance Concrete (UHPC) is one of the most promising materials for such applications [ 1 ]. Its high compressive strength (>150 MPa), tensile strength (>8 MPa) combined with enhanced flowability, and very dense microstructure are the key characteristics [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. However, an application of UHPC as an overlay on an old deteriorated concrete raises the question about the strength and long-term effects of the interfacial transition zone between new and old concrete (ITZ).…”

Section: Introductionmentioning

confidence: 99%

Eco-UHPC as Repair Material—Bond Strength, Interfacial Transition Zone and Effects of Formwork Type

et al. 2020

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A reduced carbon footprint and longer service life of structures are major aspects of circular economy with respect to civil engineering. The aim of the research was to evaluate the interfacial bond properties between a deteriorated normal strength concrete structure and a thin overlay made of Eco-UHPC containing 50 wt% of limestone filler. Two types of formwork were used: untreated rough plywood and surface treated shuttering plywood. The normal strength concrete elements were surface scaled using water jets to obtain some degradation prior to casting of the UHPC overlay. Ultrasonic pulse velocity (UPV), bond test (pull-off test), and Scanning Electron Microscopy (SEM) combined with Energy Dispersive Spectrometry (EDS) were used for analysis. Elements repaired with the Eco-UHPC showed significantly improved mechanical properties compared to the non-deteriorated NSC sample which was used as a reference. The bond strength varied between 2 and 2.7 MPa regardless of the used formwork. The interfacial transition zone was very narrow with only slightly increased porosity. The untreated plywood, having a rough and water-absorbing surface, created a surface friction-based restraint which limited microcracking due to autogenous shrinkage. Shuttering plywood with a smooth surface enabled the development of higher tensile stress on the UHPC surface, which led to a more intensive autogenous shrinkage cracking. None of the formed microcracks penetrated through the entire thickness of the overlay and some were partly self-healed when a simple water treatment was applied. The project results showed that application of UHPC as repair material for concrete structures could elongate the lifespan and thus enhance the sustainability.

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Experimental study on flexural behavior of damaged reinforced concrete (RC) beam strengthened by toughness-improved ultra-high performance concrete (UHPC) layer

Cited by 113 publications

References 27 publications

Strengthening of RC Beams using Steel Plate-Fiber Concrete Composite Jackets (Finite Element Simulation and Experimental Investigation)

Strengthening of RC Beams using Steel Plate-Fiber Concrete Composite Jackets (Finite Element Simulation and Experimental Investigation)

Interfacial Shear Performance of Epoxy Adhesive Joints of Prefabricated Elements Made of Ultra-High-Performance Concrete

Eco-UHPC as Repair Material—Bond Strength, Interfacial Transition Zone and Effects of Formwork Type

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