Indeed, intensive grinding of the fly ash appeared to render the fly ash more reactive. The fineness of the limestone powder within the tested range (362-812 m2/kg) had no effect on the hydration ...
Read more...Fly ash has a high potential to be converted into geopolymeric material due to its abundant supplies and low cost. However, large particle size of the fly ash caused low reactivity which results in low properties of the end product. The improvement on the fly ash properties by mechanical activation allows it as a new possible raw material in wider application besides solving the low reactivity ...
Read more...7. Investigation of the effects of fly ash – nanoparticle combination on flowability and resistance to segregation as well as strength development of eco-friendly SCC. Based on the established correlations, it was concluded that the use of nano-engineering approach and mechano-chemical activation of fly ash can provide an improved performance of
Read more...In spite that the effect of milling alone did not have sufficient research studies in the adsorption process, since its applied with other activation methods like acidification and alkalization .Modification of fly ash surface properties and morphology, can enhance the application of fly ash …
Read more...cate that mechanical activation of fly ash can be used to produce blended cements containing higher proportions of fly ash without degrading performance characteristics (Kumar et al., 2007). The effect of mechanical activation of the fine fraction of fly ash was investigated by using milled fly ash. The
Read more...Firstly, the fly ash characterization revealed a fly ash with low unburned carbon content of about 1.6% LOI pointing to a low surface area and necessitating activation. After activation, the morphology of the fly ash was changed as can be seen in Figure 1 as the BET surface area increased from about 10 m2/g to about 77 m2/g. This increased ...
Read more...Qian et al. [17] also employed a mechano-chemical activation technique where fly ash was finely ground and its properties were compared with that of the Na 2 SO 4 activated fly ash. Their results ...
Read more...Soil stabilisation using alkaline activation of fly ash for self compacting rammed earth construction ... The most common earth 6 7 construction techniques are rammed-earth and adobe masonry [1]. ... 24 65 [30] Fernández-Jiménez A, Palomo A. Composition and microstructure of alkali activated fly 1 2 ash binder: Effect of the activator. Cement ...
Read more...Since fly ash chemistry (and to a certain extent cement chemistry) varies globally and even locally, it was imperative to test the effect of these activation techniques and the possible advantages they might present on local materials from South Africa.
Read more...In this case, the activation of the fly ash cement allowed for the increase of fly ash content to 45% while still complying with internal and external specifications on setting time and strengths. Case study #4. OPTEVA™ ESE® 400 additive was adopted at an Indian cement plant that produced PPC cement according to the IS standard, with 34% fly ...
Read more...Investigation of the effects of fly ash – nanoparticle combination on flowability and resistance to segregation as well as strength development of eco-friendly SCC. Based on the established correlations, it was concluded that the use of nano-engineering approach and mechano-chemical activation of fly ash can provide an improved performance of ...
Read more...Fly ash was ball milled with 2, 4, and 6 wt.% cetyl trimethyl ammonium bromide (C-tab) surfactants using ethyl acetate as a medium in a planetary ball mill machine to achieve reduced fly ash …
Read more...This paper presents results regarding the phase composition, microstructure and textural properties of two types of aggregates, which were prepared via crushing or pelletization of alkali-activated Class F fly ash and cured under different conditions. The alkali activator was the same for aggregate products, containing an alkaline solution consisting of 8 M NaOH and Na-silicate (8 M NaOH/Na ...
Read more...The objective of this paper is to investigate the effect of mechanical activation of fly ash by grinding on physico-chemical and minerological properties. It can be established that there are numerous techniques for mechanical activation of fly ash, e.g. planetary ball mill, vibratory mill or stirred media mill.
Read more...applications of activated fly ash .The paper also covers the effect of various properties of fly ash on activation. Activation of fly ash enhance several properties of fly ash such as improvement in strength, shrinkage characteristics, acid and fire resistance, cold weather resistance, great workability,reduces CO2 emissions etc.
Read more...Chemical Activation of Low Calcium Fly Ash Part II: Effect of Mineralogical Composition on Alkali Activation P. Arjunan1, M. R. Silsbee2, and D. M. Roy2, 1Custom Building Products, 6515, Salt Lake Ave, Bell, CA 90201. 2Material Research Laboratory, The Pennsylvania State University, PA 16802. KEYWORDS: low calcium fly ash, portland cement, mineralogy, chemical activation
Read more...Circulating fluidized bed (CFB) fly ash with high loss on ignition is hard to utilize, which become a hindrance for promoting the CFB power plant. In the paper, cementitious activity of the fly ash is improved by milling it. And the effects of mechano-chemistry and carbon structure on its activity during grinding process were studied by XRD, SEM and FTIR techniques in combination with ...
Read more...• The mechanical activation of fly ash enhanced initial strength development substantially in the alkaline cements studied due to reaction kinetics: more ash reacted in less time. • Mechanical activation of ash affects the nature of the reaction products formed: a faster reaction rate generates more N-A-S-H or N,C-A-S-H gel and fewer ...
Read more...Chemical Activation of Low Calcium Fly Ash Part 1: Identification of Suitable Activators and their Dosage P. Arjunan1, M. R. Silsbee2, and D. M. Roy2, 1Custom Building Products, 6515, Salt Lake Ave, Bell, CA 90201. 2Material Research Laboratory, The Pennsylvania State University, PA 16802. KEYWORDS: low calcium fly ash, portland cement, mechanical activation, chemical activation
Read more...In this study, Na 2 CO 3 was used as activator to roast and activate high-alumina fly ash (HAFA), and the vacuum roasting technology was used to enhance the activation process of HAFA. The effects of the vacuum conditions on the activation of HAFA roasted using conventional and microwave heating were investigated.
Read more...In this paper the main reaction products formed in alkali activated fly ash systems have been studied by using Infrared Spectroscopy. The main variables of work were: soluble silica content in the alkaline activating solution (0% SiO 2; 1.62% SiO 2; 5.40% SiO 2 and 9.07% SiO 2) and thermal curing time (8 h, 60 and 180 days). The results obtained have shown that the main reaction product …
Read more...Herein, cement is totally replaced by mineral admixtures rich in aluminosilicates such as fly ash and is formed by the alkali activation using alkaline activator solutions, such as sodium hydroxide (NaOH) and sodium silicate (Na 2 SiO 3). Fly ash, a waste material from industry, can be incorporated in the manufacture of geopolymer concrete.
Read more...Alkali-activated fly ash (AAF) is a promising material that exhibits comparable material properties as cement-based materials but with much less CO2 emission. In the present work, the effect of activating solution (SiO2 and Na2O content) on the performance of AAF was studied by means of isothermal calorimetry and X-ray diffraction analysis. Meanwhile, the pore structure of AAF was …
Read more...Highlights NaOH or Na 2 CO 3 greatly improved the extraction of Al 2 O 3 from coal fly ash. NaOH and Na 2 CO 3 improved the disaggregation of mullite at lower and higher temperatures. The mixed additives containing NaOH and Na 2 CO 3 obtained better activation effect on coal fly ash. The mechanisms about the additives on the effect of activation of coal fly ash were discussed.
Read more...In the study, the effect of 4% sodium sulfate (Na 2 SO 4) as an activator on cement pastes with 0%, 20%, and 40% fly-ash replacements and a low water-to-cementitious materials ratio of 0.30 was investigated.The investigation was conducted to evaluate the effectiveness of the technique for the utilization of fly ash in developing sustainable concrete.
Read more...A detailed analysis of the effects of mechanical activation and temperature on the dissolution process of a Portuguese Class F fly ash was developed in this paper. The evolution of the silica and alumina dissolved and transferred to the aluminosilicate gel was characterised.
Read more...characteristics of coal fly ash have been enhanced [11]. This study aimed enhanced reactivity fly ash by mechanical activation with a vibratory ring mill, planetary ball mill and conventional ball mill as well. At the same time, the best mechanical activation technique finding for mechanical activa-tion of fly ash could be the aim of this study.
Read more...Figure 1 shows the effect of strength beyond 9 hours is not much fineness of fly ash on the compressive significant. strength of geopolymer concrete heating in • The compressive strength of geopolymer oven and other parameters like Solution-to- concrete under oven heating at 90°C Fly ash ratio of 0.35, water-to-Geopolymer after 24hours is ...
Read more...Alkali-activated fly ash (AAFA) manufactured with conventional thermal curing (85oC) shows comparative mechanical properties to Portland cement (PC) based system, demonstrating its potential as a future low-carbon and environmentally friendly alternative cementitious material. However, the environmental benefit which could have been achieved from the low carbon nature of AAFA is often …
Read more...Using phospho-specific antibodies we observed activation of p38 MAP kinase, p44/42 MAP kinase (ERK1/2) and p70(S6) kinase. Prolonged incubation with fly ash increased the expression of collagen 1 and TGF-beta1, but decreased mRNA levels of MMP9 and TNF-alpha. Cell proliferation was inhibited at high concentrations of fly ash.
Read more...Activation analysis is one of the major techniques for the determination of many minor and trace elements in a large variety of solid environmental and pollution sam- ples, such as atmospheric aerosols, particulate emissions, fly ash, coal, incineration ash
Read more...PDF | This paper is focused on the elucidation of mechanical activation effect of circulating fluidized bed combustion fly ash (Amgalan Thermal Station,... | Find, read and cite all the research ...
Read more...Other studies on the effects of sulfate on the alkali activation of fly ash, metakaolin and low-Ca ferronickel slag have indicated that the precipitation of some zeolites is enhanced, and the ...
Read more...Effect of sulfate activation of fly ash on mechanical and durability properties of recycled aggregate concrete. ... This study provides a cheap and practical technique to overcome the drawbacks of high-volume FA-RCA concrete. The outcomes of this research will help in maximizing the consumption of demolition wastes and FA into new concrete ...
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