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Home > Publications > International Concrete Abstracts Portal
Showing 1-5 of 180 Abstracts search results
Document:
24-169
Date:
December 19, 2024
Author(s):
Eman Ibrahim, Abdoulaye Sanni B., Ahmed E. Salama, Ammar Yahia, and Brahim Benmokrane
Publication:
Structural Journal
Abstract:
This study investigated the serviceability behavior and strength of polypropylene-fiber (PF) reinforced self-consolidating concrete (PFSCC) beams reinforced with glass fiber-reinforced polymer (GFRP) bars. Five full-scale concrete beams measuring 3100 mm long × 200 mm wide × 300 mm deep (122.1 × 7.9 × 11.8 in.) were fabricated and tested up to failure under four-point bending cyclic loading. Test parameters included the longitudinal reinforcement ratio (0.78, 1.18, and 1.66%) and polypropylene fiber (PF) volume (0, 0.5, and 0.75% by concrete volume). The effect of these parameters on serviceability behavior and strength of the test specimens is analyzed and discussed herein. All the beams were evaluated for cracking behavior, deflection, crack width, strength, failure mode, stiffness degradation, and deformability factor. The test results revealed that increasing the reinforcement ratio and PF fiber volume enhanced the serviceability and flexural performance of the beams by effectively restraining crack widths, reducing deflections at the service and ultimate limit states, and decreasing residual deformation. The stiffness exhibited a fast-to-slow degradation trend until failure for all beams, at which point the beams with a higher reinforcement ratio and fiber volume evidenced higher residual stiffness. The cracking moment, flexural capacities, and crack width of the tested beams were predicted according to the North American codes and design guidelines and compared with the experimental ones. Lastly, the deformability for all beams was quantified with the J-factor approach according to CSA S6-19. Moreover, the tested beams demonstrated adequate deformability as per the calculated deformability factors.
DOI:
10.14359/51745489
22-290
August 1, 2024
Ahmed T. Omar, Basem H. AbdelAleem, and Assem A. A. Hassan
Materials Journal
Volume:
121
Issue:
4
This paper investigates the structural performance of lightweight self-consolidating concrete (LWSCC) and lightweight vibrated concrete (LWVC) beam-column joints (BCJs) reinforced with monofilament polyvinyl alcohol (PVA) fibers under quasistatic reversed cyclic loading. A total of eight exterior BCJs with different lightweight aggregate types (coarse and fine expanded slate aggregates), different PVA fiber lengths (8 and 12 mm [0.315 and 0.472 in.]), and different percentages of fiber (0.3 and 1%) were cast and tested. The structural performance of the tested joints was assessed in terms of failure mode, hysteretic response, stiffness degradation, ductility, brittleness index, and energy dissipation capacity. The results revealed that LWSCC specimens made with expanded slate lightweight fine aggregates (LF) appeared to have better structural performance under reversed cyclic loading than specimens containing expanded slate lightweight coarse aggregates (LC). Shortening the length of PVA fibers enhanced the structural performance of LWSCC BCJs in terms of initial stiffness, load-carrying capacity, ductility, cracking activity, and energy dissipation capacity compared to longer fibers. The results also indicated that using an optimized LWVC mixture with 1% PVA8 fibers and a high LC/LF aggregate ratio helped to develop joints with significantly enhanced load-carrying capacity, ductility, and energy dissipation while maintaining reduced self-weight of 28% lower than normalweight concrete (NWC).
10.14359/51740773
22-192
July 1, 2023
Omar A. Kamel, Ahmed A. Abouhussien, Assem A. A. Hassan, and Basem H. AbdelAleem
120
This study investigated using acoustic emission (AE) monitoring to assess the abrasion performance of fiber-reinforced selfconsolidating concrete at cold temperatures (–20°C). In addition, the study targeted correlating the abrasion damage to AE data through AE intensity analysis parameters. Seven concrete mixtures were developed with variable water-binder ratios (w/b) (0.4 and 0.55), fiber types (steel and polypropylene synthetic fibers), fiber lengths (19 and 38 mm), and fiber volumes (0.2 and 1%). Tests on 100 mm cubic samples were conducted at –20 and 25°C, for comparison, according to the rotating-cutter technique in conjunction with AE monitoring. Characteristics of the AE signals such as signal amplitudes, number of hits, and signal strength were collected and underwent b-value and intensity analyses, resulting in three subsidiary parameters: b-value, severity (Sr), and the historic index (H(t)). A clear correlation between abrasion damage progress and AE parameters was noticed. Analyzing AE parameters along with experimental measurements generally revealed a better abrasion resistance for all mixtures when tested at –20°C compared to those at room temperature. The mixtures with steel fibers, lower w/b values, shorter fibers, and higher fiber volume showed improved abrasion resistance irrespective of temperature. Noticeably, the mixtures containing longer fibers, higher w/b values, or lower fiber dosages experienced a more pronounced enhancement ratio in the abrasion resistance when cooled down to sub-zero temperatures. Two damage classification charts were developed to infer the mass loss percentage and wear depth due to abrasion using intensity analysis parameters: Sr and H(t).
10.14359/51738806
21-442
M. Aflakisamani, S. Mousa, H. M. Mohamed, E. A. Ahmed, and B. Benmokrane
Advances in new lightweight self-consolidating concrete (LWSCC) mixture designs have led to the construction of new concrete structures with much lower weight and higher strengths. The integration of glass fiber-reinforced polymer (GFRP) bars with LWSCC can be used effectively in Accelerated Bridge Construction (ABC) with longer spans and less shippingcost to build durable bridges with smaller cross sections andextended service lives. This study aimed at evaluating the effectiveness of this type of concrete for building concrete bridgedeck slabs with GFRP reinforcement. Five full-scale edgerestrained concrete bridge-deck slabs were fabricated, simulating a slab-on-girder bridge deck commonly used in North America. The bridge-deck slabs were 3000 mm (118.1 in.) in length, 2500 mm (98.4 in.) in width, and 200 mm (7.9 in.) in thickness. The test parameters included reinforcement type (sand-coated or helically wrapped GFRP and steel) and reinforcement ratio (ranging from 0.44 to 1.15%). The bridge-deck slabs were designed according to the Canadian Highway Bridge Design Code. The specimens were exposed to a concentrated load over a contact area of 250 x 600 mm (9.8 x 23.6 in.), which simulates the footprint of a sustainedtruck wheel load (87.5 kN CL-625 truck), as specified in Canadian standards. The test results indicate that the failure mode of all deck slabs was punching shear. The recorded ultimate load capacities for all specimens exceeded the design factored load, which validates the use of GFRP-reinforced LWSCC for the construction of bridge-deck slabs. It was also concluded that the surface conditions of the GFRP bars (sand coated or helically wrapped) had a minor effect on the cracking, deflection, and behavior of the testedLWSCC deck slabs. In addition, increasing the axial-reinforcement stiffness in the GFRP-reinforced slabs significantly increased the ultimate capacity and reduced maximum crack width, reinforcement strains, and midspan deflection at ultimate load.
10.14359/51738717
21-152
May 1, 2023
Shehab Mehany, Hamdy M. Mohamed, and Brahim Benmokrane
3
This study investigates the flexural behavior and serviceabilityperformance of lightweight self-consolidating concrete (LWSCC) beams reinforced with basalt fiber-reinforced polymer (BFRP) bars. Eleven reinforced concrete beam specimens with a crosssectional width and height of 200 mm (7.87 in.) and 300 mm (11.81 in.), respectively, and with a total length of 3100 mm (122.05 in.) were tested under a four-point bending load up to failure. Nine specimens were made with LWSCC, while the other two were made with normalweight concrete (NWC) as reference specimens. The test parameters were concrete density (LWSCC and NWC), reinforcement type (sand-coated BFRP, helically grooved BFRP, thread-wrapped BFRP, or steel), and longitudinal BFRP reinforcement ratio. The test results indicate that the LWSCC yielded lower beam self-weight (density of 1800 kg/m3 [112.4 lb/ft3]) than the NWC. Increasing the BFRP reinforcement ratio increased the normalized moment capacity of the LWSCC specimens. Thetest results were compared from the standpoint of the cracking and ultimate moment, deflection, and crack-width design provided in the available design standards for FRP-reinforced elements. The comparison indicates that the experimental moment capacities of the LWSCC and NWC beams were in good agreement with the predictions based on design standards with an average accuracy of 90%. The crack width of the LWSCC beams was affected by the surface configuration of the BFRP bars, while the deflection was not significantly affected by the concrete density. The Canadian design code yielded accurate predictions with a bond-dependent coefficient of 0.8 and 1.0 for the sand-coated and helically grooved BFRP bars, respectively, in the LWSCC.
10.14359/51738502
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