Research Article
Influence of Steel Fiber on Compressive Strength and Crack Pattern of Recycled Aggregate Concrete
Issue:
Volume 13, Issue 2, April 2025
Pages:
61-67
Received:
2 March 2025
Accepted:
12 March 2025
Published:
31 March 2025
DOI:
10.11648/j.ajce.20251302.11
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Views:
Abstract: The use of recycled aggregates rather than new aggregates is suggested by the depletion of natural resources and demolition trash. Compared to natural aggregate, recycled aggregate gives concrete less strength. Concrete can be strengthened by adding fiber, such as steel fibers, at a low volumetric proportion. This study aims to determine the concrete's compressive strength by adding steel fiber (30 mm in length) to volume fractions of 0.45%, 0.9%, 1.35%, and 1.80% of the concrete. Coarse aggregates specially recycled stone was obtained from demolished concrete structures and laboratory waste and used after proper treatment. Based on the mix design, a concrete strength of 30 MPa and a water to cement ratio of 0.46 were selected. This type of concrete was anticipated to be utilized for RCC beams. To make sure the designed concrete was workable, the slump test was conducted. The slump showed decreasing value when steel fiber was added accordingly. After seven and twenty-eight days, the concrete cubes' compressive strength was finally measured. With steel fiber utilized at the ideal proportion of 1.35% of the volume of concrete, the results demonstrated that the concrete achieved the required strength and slightly improved in compressive strength. In conclusion, steel fiber combined with recycled stone in the right proportion could be a sustainable substitute for RCC structures.
Abstract: The use of recycled aggregates rather than new aggregates is suggested by the depletion of natural resources and demolition trash. Compared to natural aggregate, recycled aggregate gives concrete less strength. Concrete can be strengthened by adding fiber, such as steel fibers, at a low volumetric proportion. This study aims to determine the concre...
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Research Article
Effects of Masonry Infills on the Lateral Stiffness of Reinforced Concrete Buildings
Daniel Dibaba Awayo*
,
Yohannes Gudeta Deressa
Issue:
Volume 13, Issue 2, April 2025
Pages:
68-80
Received:
2 March 2025
Accepted:
18 March 2025
Published:
31 March 2025
DOI:
10.11648/j.ajce.20251302.12
Downloads:
Views:
Abstract: Block infills are usually regarded as non-loadbearing components in buildings, and are frequently neglected in the analysis and design of building structures. The main objective of this study is to perform static nonlinear analysis of hollow concrete block (HCB) infilled reinforced concrete buildings (RC) subjected to a seismic excitation. For this study, three different buildings were selected as case studies: a seven-story, an eleven-story, and a sixteen-story building, each with a standard floor plan. Bare RC frame buildings were analyzed and designed on ETABS based on Ethiopian Buildings Code Standards (ES EN: 2015). While numerical modeling and static pushover analysis of the designed building model cases were computed using SeismoStruct. The masonry panel model was employed to reproduce the behaviour of the full-scale infilled frame model using diagonal compression struts. The results from the pushover analysis were used to determine the fundamental vibration period and generate the capacity curves. It was observed that the presence of infills had a highly significant impact, causing a considerable increase in base shear until the infills began to crack. Additionally, the infills played a major role in reducing the fundamental vibration period of the structures. A seismic base shear of 5,150kN was found at significant damage performance levels with the corresponding roof displacements of 300, 420, and 600mm for seven-story, eleven-story and sixteen-story building models respectively. While their respective on set cracks of infills were observed at 17mm, 20mm and 24mm roof displacement. Therefore, for relatively high-rise buildings, the contribution of infills in terms of stiffness and energy dissipation becomes more important, as their impact on base shear and fundamental period is both substantial and significant.
Abstract: Block infills are usually regarded as non-loadbearing components in buildings, and are frequently neglected in the analysis and design of building structures. The main objective of this study is to perform static nonlinear analysis of hollow concrete block (HCB) infilled reinforced concrete buildings (RC) subjected to a seismic excitation. For this...
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