Ultra-high-performance fiber-reinforced concrete. Part V: Mixture design, preparation, mixing, casting, and curing

Akeed, Mahmoud H.; Qaidi‏, Shaker; Ahmed, Hemn Unis; Faraj, Rabar H.; Majeed, Samadar S.; Mohammed, Ahmed; Emad, Wael; Tayeh, Bassam A.; Azevedo, Afonso Rangel Garcez de

doi:10.1016/j.cscm.2022.e01363

Cited by 26 publications

(22 citation statements)

References 86 publications

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“…The results show a decrease in the flow ability of the UHPC mix, as the fiber percentage increases from 1.33% to 1.53% (15% increase). Previous studies (Boulekbache et al, 2010;Sahoo et al, 2019;Akeed et al, 2022a) have shown that the reduction in flowability associated with the use of fiber reinforcements can be attributed to: 1) the large length and surface area of the fibers compared to the aggregates causing an increase in the cohesive forces between the two constituents; 2) fibers effects on altering the granular skeleton structure of the mix and hindering its flow; 3) fiber reinforcements tend to flow perpendicular to the paste; thus they generate resisting forces and moments to the flow velocity of the fresh mixture (Ahmed H. U. et al, 2022;Abd et al, 2022;Akeed et al, 2022b;Abd et al, 2023).…”

Section: Flow Table Testmentioning

confidence: 99%

Influence of ternary hybrid fibers on the mechanical properties of ultrahigh-strength concrete

et al. 2023

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Ultra-high performance concrete (UHPC), an advanced class of fiber-reinforced cementitious material with extraordinary mechanical properties, low permeability, shrinkage and creep, and high energy absorption capacity, has seen steady increase in use, with applications covering construction of new members and retrofit of existing ones. Fibers are added in the UHPC mix to bridge cracks, carry tensile stresses, and contribute greatly to member ductility and load capacity. Hybrid fibers comprising micro and macro types are beneficial where the first type resists microcracking and the second targets macrocracking. This study investigates the effects of blending three fiber types, namely, hooked-end steel (referred to as type 1, representing macro fibers class), straight-end steel (type 2, intermediate size fibers), and carbon (type 2, micro size fiber), on the mechanical properties of UHPC. Experimental tests were performed to characterize the following mechanical properties: flowability, compressive strength, tensile strength, flexural strength, modulus of elasticity, and dry shrinkage. The primary variable in the tests was the blending of different fiber types, using either a unary form of type 1, a binary form of type 1 and 3 or type 2 and 3, and a ternary mix of all three types, at 1.56% dosage by volume. The mix with ternary fibers yielded a compressive strength, tensile strength, flexural strength, and modulus of elasticity that is 14%–17%, 14%–16.8%, 43.66%–22.16%, and 12%–16%, larger than the same respective properties of the mix with unary fibers. In addition, ternary fibers increased the cohesiveness of the mix by 17% and 26% compared to unary fibers.

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Section: Flow Table Testmentioning

confidence: 99%

Influence of ternary hybrid fibers on the mechanical properties of ultrahigh-strength concrete

et al. 2023

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“…Worldwide, a substantial amount of WG is produced, and most of it ends up in landfills, where it puts dangers to both human and environmental health [ 35 ]. Furthermore, cementitious composites are the most widely used building materials [ [81] , [82] , [83] ], but their increased consumption results in the loss of natural resources and the release of CO 2 . To reduce environmental impact, WG might be used to partially substitute cement and sand in cementitious composites.…”

Section: Discussionmentioning

confidence: 99%

Evaluating the effectiveness of waste glass powder for the compressive strength improvement of cement mortar using experimental and machine learning methods

Khan,

Ahmad,

Amin

et al. 2023

Heliyon

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“…Therefore, Equations ( 5) and ( 6) ensured the proper performance of the shear test. The shear stress in the notched plane was calculated according to Equation (7) for the dimensions of every prism size defined in Table 2.…”

Section: Mechanical Testsmentioning

confidence: 99%

“…The load carrying capacity at serviceability and at the ultimate limit state conditions of constructive systems made by plain and reinforced concrete (PC and RC, respectively) increases with the contribution of fiber reinforcement due to the ability of fibers bridging cracks to support the load transferred between the crack faces and to restrain their width and sliding. Therefore, the inclusion of fibers results in a matrix of higher energy absorption capacity and post-cracking strength than the PC, but the fiber reinforcement efficiency depends on the volume and type of fibers, the quality of the matrix and the batching methods involved due to the influence of fiber distribution and orientation [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. These advantages have been demonstrated in the application of various structural elements, such as slender beams [ 8 , 9 , 10 ], deep beams [ 11 , 12 , 13 ], slabs [ 14 , 15 , 16 ], columns [ 17 ] and tunnel lining segments [ 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

Relation between Shear Stresses and Flexural Tensile Stresses from Standardized Tests of Extracted Prismatic Specimens of an SFRC Bridge Girder

et al. 2022

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Experimental research on the direct shear behavior of fiber-reinforced concrete is often carried out using prisms molded with specific dimensions for a standardized test. However, the flow of fresh concrete in these molds can be different than in the case of a full-scale structural element. This is important considering that the flow direction highly influences the distribution and orientation of fibers. In addition, most of the studies did not relate their shear results to other mechanical properties. In contrast, this study attempted to deepen the experimental knowledge of the crack propagation of a steel fiber-reinforced concrete (SFRC) used in a full-scale prototype of a bridge box girder built in the laboratory. Prismatic specimens were sawn from webs and top flanges of this prototype. Serving as references, additional specimens were molded in wooden boxes. In a previous study of our research group, both had been tested under a three-point notched bending configuration maintaining test conditions proportional to the EN14651 specifications. From each of the previously flexurally tested specimens, two prismatic specimens suitable for the Fédération Internationale de la Précontrainte (FIP) shear test setup were extracted by adopting a cutting methodology that avoided the damage induced by the flexural tests to be part of the FIP specimens. These FIP specimens were tested in almost pure shear loading conditions for assessing the performance of SFRC. Computer tomography images and photos of the shear failure faces were used to determine the distribution and density of fibers. The results demonstrated that the peak loads were proportional to the fiber density at the shear failure section. Assuming that the SFRC conditions of the webs were representative of a common batching procedure in the construction industry, the results from the tests in specimens extracted from these webs were adopted to establish shear stress/flexural tensile stress ratios vs. crack mouth opening displacement curves. The curves belonging to cross-sections of a similar fiber density in the shear and flexural cases allowed for the proposal of a normalized crack-dilatancy relation composed of three stages of the crack propagation. In addition, a trilinear crack width–slip relation was established using the same set of specimens. The relevancy of this proposal is that the shear response can be estimated from a widely accepted standardized flexural test, which demands a simpler instrumentation and is also easier to execute than the shear setup.

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Ultra-high-performance fiber-reinforced concrete. Part V: Mixture design, preparation, mixing, casting, and curing

Cited by 26 publications

References 86 publications

Influence of ternary hybrid fibers on the mechanical properties of ultrahigh-strength concrete

Influence of ternary hybrid fibers on the mechanical properties of ultrahigh-strength concrete

Evaluating the effectiveness of waste glass powder for the compressive strength improvement of cement mortar using experimental and machine learning methods

Relation between Shear Stresses and Flexural Tensile Stresses from Standardized Tests of Extracted Prismatic Specimens of an SFRC Bridge Girder

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