Geopolymer Cements from Slag, Fly Ash and Silica Fume Activated with Sodium Hydroxide and Water Glass

2017 ◽  
Vol 66 (6) ◽  
pp. 226-231 ◽  
Author(s):  
H. H. M. Darweesh
Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3215
Author(s):  
Xinhui Liu ◽  
Chunfeng Hu ◽  
Longsheng Chu

Geopolymer as an alternative to cement has gained increasing attention. The aim of this article is to study the influence of the silica fume content and activator type on the porous fly ash-based geopolymer with silica fume as foaming agent. Geopolymeric foams were fabricated using low-calcium fly ash, silica fume, and sodium-based alkaline activator as initial materials. The designed silica fume contents were 0, 15, 30, and 45 wt % and two kinds of activators of water glass and sodium hydroxide were used for comparison. Phase composition, microstructure, mechanical properties and sound insulation properties of as-prepared bulks were systematically investigated. It was found that, with increasing silica fume content, the density and compressive strength decreased simultaneously, whereas the porosity and sound insulation performance were effectively enhanced. At the silica fume content of 45% with sodium hydroxide as activator, the porosity was increased 3.02 times, and, at the silica fume content of 45% with water glass as activator, the mean sound insulation value of 43.74 dB was obtained.


This paper presents a definite exploratory investigation on penetrability qualities of granite powder (GP) concrete. The primary parameter researched in this investigation was M30 and M60 grades concrete with substitution of sand by GP of 0, 25,50 and 100 and concrete as fractional supplanting with super plasticiser, fly ash, slag and silica fume. The antacid arrangement utilized for present examination is the mix of sodium hydroxide and sodium silicate arrangement. The test example was 50 mm (thick) x 100 mm (diameter) cylinder shapes heat-relieved at 60°C in an oven. The variety was concentrated on the examples exposed to ambient air just as oven heat relieving. non-destructive tests on cylinders with the help of rebound hammer for a time of 28, 56, 90, 180 and 365 days. The test outcomes show that the substitution of rock and incomplete substitution of admixtures display better execution


2011 ◽  
Vol 368-373 ◽  
pp. 3240-3245
Author(s):  
Zhi Jun Zhou ◽  
Hui Li ◽  
Qiang Song ◽  
Bao Jing Shen

In this paper, water glass was chosen as activator to prepare Alkali-activated slag(AAS) cement. Effects of modulus and dosage of water glass, and admixture (fly ash, slag and silica fume) on the strength of AAS cement was investigated. It was found that the modulus of water glass had great effect on the strength of AAS cement when the mixing amount of water glass was less than 12%. With the incorporation of fly ash or slag, the strength of AAS cement decreased, however the incorporation of silica fume could promote the flexural and compressive strength of AAS cement slightly.


2019 ◽  
Vol 65 (1) ◽  
pp. 3-16 ◽  
Author(s):  
V.C. Prabha ◽  
V. Revathi

AbstractAn attempt was made in the present work to study the compressive strength and microstructure of geopolymer containing high calcium fly ash (HCFA) and silica fume. Concentration of sodium hydroxide solution 8M, 10M, 12M & 14M, liquid to binder ratio 0.5 and sodium hydroxide to sodium silicate ratio 2.5 were selected for the mixes. Geopolymer mortar test results indicated that the mix with 40% silica fume by the weight of HCFA yielded higher compressive strength under ambient curing. The XRD pattern typically shows the major portion of amorphous phase of geopolymer. The existence of C-A-S-H gel, N-A-S-H gel and hydroxysodalite gel products were observed through SEM which developed dense microstructure and thus enhanced strength of HCFA and silica fume geopolymer.


2014 ◽  
Vol 1000 ◽  
pp. 67-70 ◽  
Author(s):  
Martin Sisol ◽  
Juraj Mosej ◽  
Miroslava Drabová ◽  
Ivan Brezani

Effect of mechanical activation of fly ashes on strength of alkali activated binders is investigated. Four different kinds of fly ashes are mechanically activated. The aim of mechanical activation is to increase the reactivity of fly ashes. Mechanically activated fly ash is used as an admixture to the untreated original fly ash in proportion of 0, 50, 75 and 100 %. Fly ashes are alkali activated with solutions containing sodium hydroxide and sodium water glass. Compressive and flexural strength is tested on hardened alkali activated binders.


2018 ◽  
Vol 17 (9) ◽  
pp. 2023-2030
Author(s):  
Arnon Chaipanich ◽  
Chalermphan Narattha ◽  
Watcharapong Wongkeo ◽  
Pailyn Thongsanitgarn

Author(s):  
A. Z. Mohd Ali ◽  
◽  
N. A. Jalaluddin ◽  
N. Zulkiflee ◽  
◽  
...  

The production of ordinary Portland cement (OPC) consumes considerable amount of natural resources, energy and at the same time contribute in high emission of CO2 to the atmosphere. A new material replacing cement as binder called geopolymer is alkali-activated concrete which are made from fly ash, sodium silicate and sodium hydroxide (NaOH). The alkaline solution mixed with fly ash producing alternative binder to OPC binder in concrete named geopolymer paste. In the process, NaOH was fully dissolved in water and cooled to room temperature. This study aims to eliminate this process by using NaOH in solid form together with fly ash before sodium silicate liquid and water poured into the mixture. The amount of NaOH solids were based on 10M concentration. The workability test is in accordance to ASTM C230. Fifty cubic mm of the geopolymer paste were prepared which consists of fly ash to alkaline solution ratio of 1: 0.5 and the curing regime of 80℃ for 24 hours with 100% humidity were implemented. From laboratory test, the workability of dry method geopolymer paste were decreased. The compressive strength of the dry mix of NaOH showed 55% and the workability has dropped to 58.4%, it showed strength reduction compared to the wet mix method.


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