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RISS 인기검색어
- 검색키워드
- 저자 : Mohamed Elchalakani (검색결과 4 건)
- 무료
- 기관 내 무료
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Durability assessment of self-compacting concrete with fly ash
Sahar Deilami,Farhad Aslani,Mohamed Elchalakani 사단법인 한국계산역학회 2017 Computers and Concrete, An International Journal Vol.19 No.5
Self-Compacting Concrete (SCC) is a new technology capable to flow without segregation or any addition of energy which leads to efficient construction and cost savings. In this study, the effect of replacing the Ordinary Portland Cement (OPC) with Fly Ash (FA) on the strength, durability of the concrete was investigated experimentally, and carbon footprint and cost were also assessed. Four different replacement FA ratios (0%, 20%, 40% and 60%) were used to create four SCC mixes. Standard test methods were used to determine the workability, strength, and durability of the SCC mixes including resist chloride ion penetration, water permeability, water absorption, and initial surface absorption. The axial cube compressive strength tests were performed on the SCC mixes at 1, 7, 14, 28 and 35 days. Replacing the OPC with FA had a significant positive impact on chloride iron penetration resistance and water absorption but had a considerable negative impact on the compressive strength. The SCC mix with 60% FA had 36.7% and 15.8% enhancement in the resistance to chloride ion penetration and water absorption, respectively. Evaluation of the carbon footprint and the cost of each SCC mixes showed the CO2 emissions mixes 1, 2, 3 and 4 were significantly reduced by increasing the FA content from 0% to 60%. Compared with the control mix, the cost of all mixes increased when the FA content increased, but no significant differences were seen between the estimated costs of all four mixes.
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Mechanical and durability properties of self-compacting concrete with blended binders
T.Y. Xie,M. Elchalakani,M.S. Mohamed Ali,M.H. Dong,A. Karrech,G. Li 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.22 No.4
Over the past three decades, self-compacting concrete (SCC), which is characterized by its superior rheological properties, has been gradually used in construction industry. It is now recognized that the application of SCC using supplementary cementitious materials (SCM) is highly attractive and promising technology reducing the environmental impact of the construction industry and reducing the higher materials costs. This paper presents an experimental study that investigated the mechanical and durability properties of SCCs manufactured with blended binders including fly ash, slag, and micro-silica. A total of 8 batches of SCCs were manufactured. As series of tests were conducted to establish the rheological properties, compressive strength, and durability properties including the water absorption, water permeability, rapid chloride permeability and initial surface absorption of the SCCs. The influences of the SCC strength grade, blended types and content on the properties of the SCCs are investigated. Unified reactive indices are proposed based on the mix proportion and the chemical composition of the corresponding binders are used to assess the compressive strength and strength development of the SCCs. The results also indicate the differences in the underlying mechanisms to drive the durability properties of the SCC at the different strength grades.
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Tests of concrete-filled double skin CHS composite stub columns
Xiao-Ling Zhao,Raphael Grzebieta,Mohamed Elchalakani 국제구조공학회 2002 Steel and Composite Structures, An International J Vol.2 No.2
This paper describes a series of compression tests carried out on concrete filled double skin tubes (CFDST). Both outer and inner tubes are cold-formed circular hollow sections (CHS). Six section sizes were chosen for the outer tubes with diameter-to-thickness ratio ranging from 19 to 57. Two section sizes are chosen for the inner tubes with diameter-to-thickness ratio of 17 and 33. The failure modes, strength, ductility and energy absorption of CFDST are compared with those of empty single skin tubes. Increased ductility and energy absorption have been observed for CFDST especially for those having slender outer tubes with larger diameter-to-thickness ratio. Predictions from several theoretical models are compared with the ultimate strength of CFDST stub columns obtained in the tests. The proposed formula was found to be in good agreement with the experimental data.
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Prestress Tension Measurement Using a Single Electromagnetic Sensor
Xiao Guo,Nianchun Deng,Mengsheng Yu,Mohamed Elchalakani,Yiming Zhou 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.10
Elasto-magnetic sensors are widely used to measure the tensile force of cable structures. Generally, the size of current elasto-magnetic sensors is designed to be large enough to measure the tensile force of the entire cable. Therefore, the tensile force of a single steel strand in cables cannot be measured, which causes some engineering problems, such as that the uniformity of prestress tension and forces within steel cables cannot be determined. In this study, a single-strand elasto-magnetic sensor, called the EM17 sensor, is proposed to detect and monitor the tensile force of single steel strands. EM17 is the smallest sensor developed to date, with an inner diameter of 17 mm. In addition, a series of experiments were conducted to investigate the effects of temperature, position, shielding environment, strand relaxation, strand fatigue and sensor sealing performance on sensor accuracy. The field tests show that the EM17 sensors can accurately measure the tensile force of steel strands. The results show that the uniformity of the prestressed steel strand and the error between measurement and target values are within the range of 5%, which is considered satisfactory.
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