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RISS 인기검색어
- 검색키워드
- 저자 : Ahmed Farouk Deifalla (검색결과 4 건)
- 무료
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Self-Compacting Concrete with Partially Substitution of Waste Marble: A Review
Jawad Ahmad,Zhiguang Zhou,Ahmed Farouk Deifalla 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.4
Self-compacting concrete (SCC) is also seen as unsustainable since it uses a lot of natural resources. Recent researchers have focused on lowering construction costs and partially replacing cement with industrial waste. It is possible to effectively use various industrial wastes in concrete as cement or aggregates. Among these wastes, waste marble (WM) is a useful choice, and researchers have been interested in using WM in concrete for a couple of years. However, to pinpoint the advantages and recent advancements of research on WM as an ingredient of SCC, a comprehensive study is necessary. Therefore, the purpose of this study is to do a compressive evaluation of WM as an SCC ingredient. The review includes a general introduction to SCC and WM, the filling and passing capability of SCC, strength properties of SCC, durability, and microstructure analysis of SCC. According to the findings, WM improved the concrete strength and durability of SCC by up to 20% substitution due to micro-filling and pozzolanic reaction. Finally, the review also identifies research gaps for future investigations.
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Steel Fiber Reinforced Self-Compacting Concrete: A Comprehensive Review
Jawad Ahmad,Zhiguang Zhou,Ahmed Farouk Deifalla 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.6
Self-compacting concrete (SCC), which flows under its own weight without being compacted or vibrating, requires no outside mechanical force to move. But like normal concrete, SCC has a brittle character (weak in tension) that causes sudden collapse with no advance notification. The tensile capacity of SCC has increased owing to the addition of steel fiber (SF). Various research concentrates on increasing the tensile strength (TS) of SCC by incorporating SF. To collect information on past research, present research developments, and future research directions on SF-reinforced SCC, however, a detailed review of the study is necessary. The main aspects of this review are the general introduction of SCC, fresh properties namely slump flow, slump T50, L box, and V funnel, and strength properties such as compressive, tensile, flexure, and elastic modulus. Furthermore, failure modes of steel fiber-reinforced SCC are also reviewed. Results suggest that the SF decreased the filling and passing ability. Furthermore, improvement in strength properties was also observed. However, some studies reported that SF had no effect or even decreased compressive capacity. Additionally, SF improved the tensile capacity of SCC and avoid undesirable brittle failure. Finally, the review recommends the substitution of secondary cementitious materials in SF-reinforced SCC to improve its compressive capacity.
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Amirreza Kandiri,Pshtiwan Shakor,Rawaz Kurda,Ahmed Farouk Deifalla 한국콘크리트학회 2022 International Journal of Concrete Structures and M Vol.16 No.6
In this study, a modified Artificial Neural Network (ANN) and Support Vector Regression (SVR) with three different optimization algorithms (Genetic, Salp Swarm and Grasshopper) were used to establish an accurate and easy-to-use module to predict the lateral pressure exerted by fresh concrete on formwork based on three main inputs, namely mix proportions (cement content, w/c, coarse aggregates, fine aggregates and admixture agent), casting rate, and height of specimens. The data have been obtained from 30 previously piloted experimental studies (resulted 113 samples). Achieved results for the model including all the input data provide the most excellent prediction of the exerted lateral pressure. Additionally, having different magnitudes of powder volume, aggregate volume and fluid content in the mix exposes different rising and descending in the lateral pressure outcomes. The results indicate that each model has its own advantages and disadvantages; however, the root mean square error values of the SVR models are lower than that of the ANN model. Additionally, the proposed models have been validated and all of them can accurately predict the lateral pressure of fresh concrete on the panel of the formwork.
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Concrete Made with Partial Substitutions of Wheat Straw Ash: A Review
Jawad Ahmad,Mohamed Moafak Arbili,Muwaffaq Alqurashi,Fadi Althoey,Ahmed Farouk Deifalla 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.6
Many scientists are now focusing their attention on the utilization of valuable industrial or agricultural wastes as the primary raw material for the construction sector. These wastes, on the other hand, are affordable and readily accessible, making them ideal for commercial use while also contributing to the reduction of environmental degradation. Wheat straw ash (WTSA) is a kind of agricultural waste that has the potential to be utilized in concrete. Although many researchers are focused on utilization of WTSA in concrete. However, an updated review is required which provides easy access for the reader to get an idea about the benefits of WTSA in concrete. Therefore, this study provides a comprehensive review of the utilization of WTSA as a concrete ingredient. Physical and chemical compositions of WTSA, flowability, mechanical strength (compressive, flexure, tensile strength, and elastic modulus), and durability properties (permeability, carbonation, ultrasonic pulse velocity, alkali-silica reaction and chloride attacks) are the main aspects of this review. Results indicate that the performance of concrete improved with partial substitutions of cement with WTSA but simultaneously decreased the flowability of concrete. The optimum dose is important as higher dose results in decreased mechanical strength. The typical optimum dose ranges from 10 to 20% by weight of the binder. The performance of concrete in terms of durability was also improved but less research is carried out on the durability performance of concrete with WTSA. Additionally, despite WTSA's improvement in mechanical strength, concrete still exhibits lower tensile strain, which leads to brittle failure. Therefore, it was recommended that further study should be done to increase its tensile strength.
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