Ahmed M. Yassin , Mohammad Mohie Eldin , Mostafa S. Omar , Mohamed Ahmed Hafez , Mohamed A. Elnaggar
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For both MS and NS, different percentages of adding or replacement content were tested to study their effect on the following: (a) the workability of fresh concrete, (b) concrete compressive strength, (c) splitting tensile strength, (d) flexural behavior including flexural tensile strength, and (e) the optimum percentage of each of the MS and NS to get the maximum structural and economic benefits of using for SCHPC with CEM II/A-P. Also, through a statistical program, these experimental results were used to obtain accurate formulae that could predict both the splitting tensile strength (<em>f</em><sub><em>sp</em></sub>) and modulus of rupture (<em>f</em><sub><em>c</em></sub><sub>tr<!--> </sub>) for SCHPC with adding nano-silica. In addition, the numerical study verified the experimental results based on the finite element program ANSYS. The flexure behavior of SCHPC beams is verified using the Microplane model (recently added to ANSYS). The experimental results showed that adding NS is more effective than replacing or adding MS for SCHPC mixture with CEM II/A-P to increase the concrete compressive strength, splitting tensile strength, and flexural tensile strength, especially for the mixture with adding NS content of 4 %. The numerical results showed the ability of the coupled damage-plasticity microplane model to simulate the flexural behavior of the tested SCHPC beams with MS or NS well. This research confirms nano-silica's structural and economical efficiency in the behavior of SCHPC beams. 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引用次数: 0
摘要
水泥的大量使用增加了二氧化碳(CO2)的排放量,从而加剧了温室效应。因此,许多标准都建议在建筑中使用硅酸盐复合水泥,特别是 CEM II/A-P 水泥,作为减少二氧化碳排放的方法之一。本文通过大量的实验和数值研究,探讨了微纳米二氧化硅对水泥 CEM II/A-P 制成的自密实高性能混凝土(SCHPC)的抗弯行为和力学性能的影响。广泛的实验工作包括八种混合物:三种含微硅混合物(MS)、四种含纳米硅混合物(NS)和一种不含硅的参考混合物。对于 MS 和 NS,测试了不同比例的添加或替代含量,以研究它们对以下方面的影响:(a) 新拌混凝土的工作性,(b) 混凝土的抗压强度,(c) 裂缝拉伸强度,(d) 抗折性能(包括抗折拉伸强度),以及 (e) MS 和 NS 的最佳比例,以便在使用 CEM II/A-P 的 SCHPC 中获得最大的结构和经济效益。同时,通过统计程序,这些实验结果被用于获得精确的公式,以预测添加纳米二氧化硅的 SCHPC 的劈裂拉伸强度(fsp)和断裂模量(fctr)。此外,数值研究还基于有限元程序 ANSYS 验证了实验结果。使用 Microplane 模型(最近添加到 ANSYS 中)验证了 SCHPC 梁的弯曲行为。实验结果表明,在使用 CEM II/A-P 的 SCHPC 混合物中,添加 NS 比替换或添加 MS 更能有效提高混凝土的抗压强度、劈裂抗拉强度和抗折抗拉强度,尤其是在添加 NS 含量为 4% 的混合物中。数值结果表明,损伤-塑性耦合微平面模型能够很好地模拟加入 MS 或 NS 的 SCHPC 梁的抗弯行为。这项研究证实了纳米二氧化硅在 SCHPC 梁行为中的结构和经济效益。研究发现,在使用 CEM II/A-P 的 SCHPC 混合物中,添加 NS 的最佳比例为 4%。
Effect of nano-silica on the flexural behavior and mechanical properties of self-compacted high-performance concrete (SCHPC) produced by cement CEM II/A-P (experimental and numerical study)
The extensive use of cement exacerbates the greenhouse effect by increasing carbon dioxide (CO2) emissions. So, many standards recommend using Portland-composite cement in construction as one of the methods for reducing CO2 emissions, especially cement CEM II/A-P. This paper presents an extensive experimental and numerical study to investigate the effect of micro and nano-silica on the flexural behavior and mechanical properties of Self-Compacted High-Performance Concrete (SCHPC) produced by cement CEM II/A-P. The extensive experimental work consisted of eight mixtures: three with micro-silica (MS), four with nano-silica (NS), and a reference mixture without silica. For both MS and NS, different percentages of adding or replacement content were tested to study their effect on the following: (a) the workability of fresh concrete, (b) concrete compressive strength, (c) splitting tensile strength, (d) flexural behavior including flexural tensile strength, and (e) the optimum percentage of each of the MS and NS to get the maximum structural and economic benefits of using for SCHPC with CEM II/A-P. Also, through a statistical program, these experimental results were used to obtain accurate formulae that could predict both the splitting tensile strength (fsp) and modulus of rupture (fctr ) for SCHPC with adding nano-silica. In addition, the numerical study verified the experimental results based on the finite element program ANSYS. The flexure behavior of SCHPC beams is verified using the Microplane model (recently added to ANSYS). The experimental results showed that adding NS is more effective than replacing or adding MS for SCHPC mixture with CEM II/A-P to increase the concrete compressive strength, splitting tensile strength, and flexural tensile strength, especially for the mixture with adding NS content of 4 %. The numerical results showed the ability of the coupled damage-plasticity microplane model to simulate the flexural behavior of the tested SCHPC beams with MS or NS well. This research confirms nano-silica's structural and economical efficiency in the behavior of SCHPC beams. It was found that the optimum percentage of adding NS is 4 % for SCHPC mixtures with CEM II/A-P.
期刊介绍:
Case Studies in Construction Materials provides a forum for the rapid publication of short, structured Case Studies on construction materials. In addition, the journal also publishes related Short Communications, Full length research article and Comprehensive review papers (by invitation).
The journal will provide an essential compendium of case studies for practicing engineers, designers, researchers and other practitioners who are interested in all aspects construction materials. The journal will publish new and novel case studies, but will also provide a forum for the publication of high quality descriptions of classic construction material problems and solutions.