Phase evolution of fly ash calcium constituent at early alkali activation reaction age

This work aims to reveal the effects of zeolite on properties of fly ash based geopolymer under high temperature at 300 °C, 600 °C and 900 °C. The specimens were prepared by alkali activation of fly ash, which was partially replaced by two different types of zeolite at 10%, 20% and 30% by weight. The specimens were analyzed for the maximum compressive strength, weight loss percentage, XRD and SEM. The results highlighted that the percentage of weight loss increased with the ratio of zeolite replacement. The compressive strength of geopolymer with synthetic zeolite and natural zeolite at 7, 28, 60 days were similar. The high-temperature exposure resulted in the reduction in compressive strength in all proportions. At the same temperature, compressive strength of all specimens were not significantly different.

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Alkali activation of fly ash. Part III: Effect of curing conditions on reaction and its graphical description

Fuel ◽

10.1016/j.fuel.2010.03.051 ◽

2010 ◽

Vol 89 (11) ◽

pp. 3185-3192 ◽

Cited By ~ 87

Author(s):

M. Criado ◽

A. Fernández-Jiménez ◽

A. Palomo

Keyword(s):

Fly Ash ◽

Alkali Activation ◽

Curing Conditions

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Investigation to some Preliminary Geotechnical Properties of Soft Clay Stabilized by Fly Ash Based Geopolymers

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.857.259 ◽

2020 ◽

Vol 857 ◽

pp. 259-265

Author(s):

Jasim M. Abbas ◽

Amer M Ibrahim ◽

Abdalla M. Shihab

Keyword(s):

Fly Ash ◽

Specific Gravity ◽

Soft Clay ◽

Cost Effective ◽

Geotechnical Properties ◽

Experimental Program ◽

Dry Density ◽

Alkali Activation ◽

Plastic Behavior ◽

Maximum Dry Density

The civil engineering projects that includes soft clay within its activities has a serious concern of hazards, such hazards can be overcame by treating the existing soils by certain materials which are named as "stabilizers". The common materials that are highly used in this field are ordinary Portland cement, fly ash, lime and rice husk ash, etc. Each one of these stabilizers has its known shortcomings. The alkali activation of any alumina silicate source produces some kind of cost effective primary binding gel which is known as "Geopolymers". This study is devoted to investigate the role of liquid over fly ash ratio to some soil – FA based Geopolymers geotechnical properties. Such ratio is taken as 2.71, 3.167, 3.8 and 4.75 respectively within the experimental program and the investigated geotechnical properties are the specific gravity, liquid and plastic limit, compaction characteristics and California bearing ratio. The tests results showed that the maximum dry density decreased about 42 % at 2.71 liq/FA whereas this the specific gravity decreased 27 % at the same this ratio. In addition, the 3.8 and 4.75 of such limits revealed no plastic behavior due to the high presence of liquid.

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The Influence of Mechanical Activation of Fly Ash on the Toxic Metals Immobilization by Fly Ash-Based Geopolymers

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.761.3 ◽

2018 ◽

Vol 761 ◽

pp. 3-6 ◽

Cited By ~ 1

Author(s):

Violeta Nikolić ◽

Miroslav Komljenović ◽

Nataša Džunuzović ◽

Tijana Ivanovic

Keyword(s):

Fly Ash ◽

Mechanical Activation ◽

Toxic Metals ◽

Structural Changes ◽

Gas Adsorption ◽

Sodium Silicate Solution ◽

Silicate Solution ◽

Water Soluble ◽

Alkali Activation ◽

Alkali Activated

This paper investigates the influence of mechanical activation of fly ash on the toxic metals immobilization by fly ash-based geopolymers. Fly ash was firstly mechanically and then alkali-activated. Mechanical activation of fly ash was conducted in a planetary ball mill. Alkali activation of fly ash was carried out at room temperature by use of sodium silicate solution as an activator. Toxic metals (Pb and Cr) were added in the form of water soluble salts during the synthesis of geopolymers. The immobilization process was assessed via investigation of the mechanical and leaching properties of geopolymers. Structural changes of geopolymers during the toxic metals immobilization were assessed by means of gas adsorption and SEM analyses. Mechanical activation of fly ash led to a significant increase in geopolymer strength and to a reduced leaching of toxic metals from geopolymers.

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Fly Ash Based Lightweight Geopolymer Concrete Using Foaming Agent Technology

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.679.20 ◽

2014 ◽

Vol 679 ◽

pp. 20-24 ◽

Cited By ~ 7

Author(s):

Mohd Mustafa Al Bakri Abdullah ◽

Zarina Yahya ◽

Muhammad Faheem Mohd Tahir ◽

Kamarudin Hussin ◽

Mohammed Binhussain ◽

...

Keyword(s):

Mechanical Properties ◽

Fly Ash ◽

Room Temperature ◽

Lightweight Concrete ◽

Agent Technology ◽

Alkali Activation ◽

Geopolymer Concrete ◽

Foaming Agent ◽

Curing Conditions ◽

Foam Generator

This paper presents the mechanical properties of a lightweight geopolymer concrete synthesized by the alkali-activation of a fly ash source (FA) produced by mixing a paste of geopolymer with foam produced by using NCT Foam Generator. Two curing conditions are used, curing at room temperature and curing in an oven with a constant temperature which is 60 oC. Bulk density showed that fly ash-based geopolymer lightweight concrete is light with the density of 1225 kg/m3 - 1667 kg/m3 with an acceptable compressive strength of 17.60 MPa for the density of 1667 kg/m3.

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