Behavior of RC beams strengthened with strain hardening cementitious composites (SHCC) subjected to monotonic and repeated loads

Khalil, Abd El-Hakim; Etman, Emad; Atta, A.A.; Essam, Mohamed

doi:10.1016/j.engstruct.2017.02.049

Cited by 52 publications

(18 citation statements)

References 9 publications

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“…It is worth noting that various investigators commonly observed the delamination phenomenon of retrofitted infrastructure. [44][45][46] Table 6 summarizes the cracking behavior of the control and SHCC beams under various environmental conditions. The total number of mid-span cracks, crack density, and average crack spacing in the concrete substrate and SHCC layer of the beam specimens after failure are presented.…”

Section: Cracking Pattern For Concrete and Shcc Beam Under Various Curing Regimesmentioning

confidence: 99%

Susceptibility of strain-hardening cementitious composite to curing conditions as a retrofitting material for RC beams

Khan

Fares

Abbas

et al. 2021

Journal of Engineered Fibers and Fabrics

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Strain-hardening cement-based composites (SHCC) have recently been developed as repair materials for the improvement of crack control and strength of flexural members. This work focuses on strengthening and flexural enhancement using SHCC layer in tensile regions of flexural members under three different curing conditions. The curing conditions simulate the effect of different environmental conditions prevailing in the central and coastal regions of the Arabian Peninsula on the properties of SHCC as a retrofitting material. In this investigation, beams with SHCC layer were compared to control beams. The beams with SHCC layer of 50-mm thickness were cast. The results revealed that the flexural behavior and the load-carrying capacity of the normal concrete beam specimens under hot and dry environmental conditions were significantly reduced, lowering the ductility of the section. However, compressive strength is comparatively unaffected. Similarly, the hot curing conditions have also led to a notable reduction in the loading capacity of the beam with SHCC layer with a slight effect on its stiffness. On the other hand, steam-curing conditions have shown improvement in load-carrying capacity and a reduction in section ductility of the beam with SHCC layer. It was found that the structural unit retrofitted with SHCC layer was a curing-regime dependent as the tensile and strain-hardening properties of SHCC are highly sensitive to the alteration in the cement hydration process. A normal curing regime was found effective and satisfying the practical, cost, and performance requirements. Accordingly, a normal curing regime could be implemented to retrofit reinforced concrete (RC) beams with SHCC layers as recommended in the study.

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Section: Cracking Pattern For Concrete and Shcc Beam Under Various Curing Regimesmentioning

confidence: 99%

Susceptibility of strain-hardening cementitious composite to curing conditions as a retrofitting material for RC beams

Khan

Fares

Abbas

et al. 2021

Journal of Engineered Fibers and Fabrics

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“…Strain-Hardening Cement-based Composites (SHCC), also Engineered Cementitious Composites (ECC), represent a special type of fiber-reinforced concrete with short and randomly distributed micro-fibers in volume fractions of up to 2 %. SHCC exhibit pronounced ductility prior to failure localization [18,19], while multiple cracks forming in the strain-hardening phase yield crack widths in a favorable sense less than 100 µ m. These features make SHCC suitable both as main material for structural elements subject to extreme loading scenarios as well as supplementary applied retrofit and strengthening layers for enhanced structural durability and resilience under unfavorable exposure and loading conditions [20,21]. It is worthy of note that the constitutive nature and fresh-state properties of SHCC enable their application by spraying or lamination, which is an important prerequisite for structural strengthening through thin covers [22].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Behavior of Strain-Hardening Cement-Based Composites (SHCC) Subjected to Torsional Loading and to Combined Torsional and Axial Loading

FIGUEIREDO¹,

Curosu²,

Gonzáles³

et al. 2020

Preprint

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Strain-hardening cement-based composites (SHCC) are a novel class of fiber-reinforced concretes which exhibit high tensile strain capacity prior to failure localization. Although the tensile behavior of SHCC has been a matter of study in numerous research works, the behavior of these composites under other loading modes has scarcely been investigated. The article at hand addresses the mechanical behavior of two types of normal-strength SHCC subject to uniaxial tension, torsion, and combinations of torsional and axial loading. The SHCC under investigation were made with polyvinyl-alcohol (PVA) and ultra-high molecular weight polyethylene (UHMWPE) fibers, respectively. Digital Image Correlation (DIC) was applied to evaluate the multiple cracking process and crack opening modes in conjunction with the concretes’ axial and torsional loading histories. The study demonstrates the suitability of torsion experiments to assess the multi-axial and shear performance of SHCC, highlights the relation between multiple cracking and transfer capacity for shear forces, and emphasizes the importance of the type of reinforcing fibers on the shear strength and ductility of such composites.

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“…In the last years, the use of high-performance fiber-reinforced concrete (HPFRC) as strengthening material for existing concrete structures has increased significantly [ 1 , 2 , 3 ]. The most common strengthening technique has been based on the application of thin HPFRC layers on the old concrete surface, either longitudinally [ 4 , 5 , 6 , 7 ] or transversely [ 8 , 9 , 10 ], to improve the tension/bending or shear capacity of structural members, respectively ( Figure 1 ).…”

Section: Introductionmentioning

confidence: 99%

Composite Behavior of RC-HPFRC Tension Members under Service Loads

2020

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A significant increase of the use of high-performance fiber-reinforced concrete (HPFRC) to strengthen reinforced concrete structures (RC) has been noted for the past few years, thereby achieving composite RC-HPFRC elements. Such a technique tries to take advantage of the superior material properties of HPFRC in the ultimate and service load regimes. Many of the existing works on RC-HPFRC elements have focused on the strength increase at the ultimate load state and much less effort has been devoted to the serviceability response. The in-service performance of RC structures is governed by the behavior of the tension chord, which determines the crack pattern (crack widths are critical for durability) and deformations. The presence of HPFRC is supposed to improve serviceability due to its strain-hardening and tension-softening capacities. In this paper, the experimental analysis of composite RC-HPFRC tension members is dealt with. Specimens consisting of a RC tie strengthened with two 35 mm thick HPFRC layers have been subjected to loads in the service range so that the deformational and cracking response can be analyzed. The HPFRC has been a cement-based mortar with 3% volumetric amount of short straight steel fibers with a compressive and tensile strength of 144 MPa and 8.5 MPa, respectively. The experiments have shown that RC-HPFRC has higher stiffness, first cracking strength and reduced crack widths and deformations compared to companion unstrengthened RC. To understand the observed behavioral stages, the experimental results are compared with an analytical tension chord model, which is a simplified version of a previous general model by the authors consisting of 4 key points. In addition, the influence of time-dependent shrinkage has been included in the presented approach.

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Behavior of RC beams strengthened with strain hardening cementitious composites (SHCC) subjected to monotonic and repeated loads

Cited by 52 publications

References 9 publications

Susceptibility of strain-hardening cementitious composite to curing conditions as a retrofitting material for RC beams

Susceptibility of strain-hardening cementitious composite to curing conditions as a retrofitting material for RC beams

Mechanical Behavior of Strain-Hardening Cement-Based Composites (SHCC) Subjected to Torsional Loading and to Combined Torsional and Axial Loading

Composite Behavior of RC-HPFRC Tension Members under Service Loads

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