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عنوان فارسی مقاله:
تاثیر دمای کلسینه بر ویژگی های پوزولانی خاکستر علف فیل
عنوان انگلیسی مقاله:
Influence of calcining temperature on the pozzolanic characteristics of elephant grass ash
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
Worldwide, the constant demand for concrete, as well as the environmental impact and large amounts of energy spent in its production, have stimulated the adoption of sustainable practices by the cement industry. Overall, the main practices considered to mitigate environmental damage associated with the Portland cement manufacture include increasing the energy efficiency of processes, promoting the use of renewable energy sources, and partially replacing cement by supplementary cementitious materials. As regards the partial cement replacement by supplementary cementitious materials, silica-rich industrial and agricultural byproducts have been extensively employed for decades, i.e., fly ash, silica fume, and rice husk ash (RHA). Recently, some studies have shown the feasibility of producing pozzolan from burning of sugar cane bagasse (SCBA) [1e3], sugar cane straw [4,5] and some types of grass used as biomass. For example, Nimityongskul et al. [6] studied a pozzolanic ash produced from vetiver grass (Chrysopogon zizanioides) for using in rural areas of tropical countries. In this case, chemical and physical properties of cementitious products with ashes produced from two distinct vetiver grass genotypes were investigated. Furthermore, it was observed that pozzolanic reactions formed hydrated compounds that increased the compressive strength and reduced the water absorption of mortars. Wang et al. [7] investigated the calcining of switchgrass (Panicum vigratum L.), a low-carbon biomass fuel (carbon neutral in its life cycle), obtaining a pozzolanic ash and optimized energy output with a burning at 550 C for 4 h. Cordeiro and Sales [8] examined the performance of elephant grass (Pennisetum purpureum) ash (EGA) after distinct grass pretreatments. The results indicated that the pozzolanic activity of ashes significantly increased when the grass was pretreated with acid leaching and washing in hot water to remove impurities. A study conducted by Nakanishi et al. [9] showed a similar behavior of EGA and silica fume in terms of fixed lime values, pointing to the pozzolanic activity of this material. EGA may be an interesting alternative for several countries, i.e. Brazil, where all fly ash and blast-furnace slag sources are already incorporated by the cement industry. Elephant grass is a fast-growing biomass source [10], enabling up to two harvests per year. Seye et al. [11] highlighted thesimilarities between the sugar cane and the elephant grass since both species share similar morphological structures and chemical composition. For this reason, the ashes from these materials should likewise be expected to have similar properties, which might be an interesting aspect in the development of proper disposal strategies for EGA. In addition, the similarities with the sugar cane bagasse suggest the existence of optimal calcining conditions for production of pozzolan from elephant grass. In this context, the present work evaluated the influence of the calcining temperature of elephant grass on the pozzolanic characteristics of EGA, considering percentage of oxides, loss on ignition, X-ray diffraction, B.E.T. specific surface area, and pozzolanic activity index with cement Portland tests. Furthermore, the performance of a selected EGA was compared with a pozzolanic SCBA in a structural concrete by compressive strength tests up to 180 days of curing.
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کلمات کلیدی:
[PDF]Influence of Calcination Temperature on Characteristics and ... ajbasweb.com/old/ajbas/2011/November-2011/1010-1018.pdf Influence of Calcination Temperature on Characteristics and Pozzolanic Activity of. Palm Oil Waste Ash. 1Nurdeen M. Altwair, 1Megat A. Megat Johari, 2Syed F. Effects of Temperature on the Pozzolanic Characteristics of Metakaolin ... www.journalrepository.org/media/journals/PSIJ_33/2015/.../Salau632014PSIJ13146.pdf by MA Salau - Cited by 1 - Related articles Feb 20, 2015 - calcined at different temperatures 450ºC, 600ºC, 750ºC, 900ºC and 1050ºC comparable to the ... pozzolanic properties are then produced. Effects of Temperature on the Pozzolanic Characteristics of Metakaolin ... www.sciencedomain.org/abstract/8184 This paper focused on the thermal technique of activating pozzolanic activity of natural pozzolans, specifically calcined kaolinite clay in the form of metakaolin. Effect of Calcination Temperature on the Pozzolanic Activity of ... - Scribd https://pt.scribd.com/.../Effect-of-Calcination-Temperature-on-the-Pozzolanic-Activity... This waste. The benefits of pozzolanic materials is due to their physical and chemical characteristics. 2. in natura. such as controlled calcination temperatures. Effect of Calcination Temperature on the Pozzolanic Activity of ... - Scribd https://www.scribd.com/.../Effect-of-Calcination-Temperature-on-the-Pozzolanic-Acti... Effect of Calcination Temperature on the Pozzolanic Activity of Brazilian ... Materials with pozzolanic characteristics may be used to partially replace cement [PDF]Effect of temperature on the pozzolanic properties of Metakaolin ... - IASJ www.iasj.net/iasj?func=fulltext&aId=17256 Effect of temperature on the pozzolanic properties of Metakaolin ... to investigate the optimum calcination temperature and the optimum time of calcination at that ... Mineral Admixtures in Cement and Concrete https://books.google.com/books?isbn=1439817928 Jayant D. Bapat - 2012 - Technology & Engineering ... 2h produces CWS with good pozzolanic characteristics At higher calcination temperature, the pozzolanic activity decreases on account of (a) decarbonation ...
