Alkali-Activated Fly Ash-Slag Cement Based Nuclear Waste Forms

1992 ◽  
Vol 294 ◽  
Author(s):  
W. Jiang ◽  
X. Wu ◽  
D.M. Roy
Keyword(s):  
Fly Ash ◽  
Nuclear Waste ◽  
Freezing And Thawing ◽  
Slag Cement ◽  
Chemical Corrosion ◽  
Cement System ◽  
Main Components ◽  
High Ultimate Strength ◽  
Nuclear Waste Forms ◽  
Alkali Activated

ABSTRACTThis paper is based on the results of an in-progress research project on Alkali-Activated Cement System at MRL. The objective of this research is to establish the potential for large volume use of fly ash and slag as main components of the cement system. Alkali-activated Fly ash-slag Cement (AFC) was studied as a matrix for immobilization of nuclear waste. AFC is characterized by high early strength, high ultimate strength, low porosity, lower solubilities of the hydrates, and high resistance to chemical corrosion as well as to freezing and thawing. All these advanced properties are particularly favorable to the immobilization the nuclear wastes.

Effect of Fly Ash, MgO and Curing Solution on the Chemical Shrinkage of Alkali-Activated Slag Cement

2010 ◽  
Vol 168-170 ◽  
pp. 2008-2012 ◽  
Author(s):  
Yong Hao Fang ◽  
Ya Min Gu ◽  
Qiu Boa Kang
Keyword(s):  
Fly Ash ◽  
Ordinary Portland Cement ◽  
Alkali Concentration ◽  
Early Age ◽  
Chemical Shrinkage ◽  
Slag Cement ◽  
Alkali Activated Slag ◽  
Reduction Effect ◽  
Activated Slag ◽  
Alkali Activated

The chemical shrinkages of alkali-activated slag cement (AASC), and the effect of fly ash, MgO burnt at 900°C and the curing solutions were studied. The shrinkages were compared with that of ordinary portland cement (OPC). The results show that the chemical shrinkage of AASC is lower than that of OPC. Adding fly ash and light-burnt MgO reduced the early age chemical shrinkage, while the shrinkage-reduction effect decreased with the age. The alkality of the curing solution has significant effect on the hydration and shrinkage of AASC. The chemical shrinkage of AASC increased with the alkali concentration of the curing solution. The mechanisms of fly ash, MgO and curing solution on the shrinkage were discussed.

Research on Mechanism of Architectural Wastes Solidified by Alkali-Activated Cement and Fly Ash

2012 ◽  
Vol 446-449 ◽  
pp. 2708-2713 ◽  
Author(s):  
Qin Li ◽  
Xiao Jun Zhou ◽  
Zhuo Yin Jiang ◽  
Ke Wei Sun
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Hydration Products ◽  
Testing Methods ◽  
Fly Ashes ◽  
Comparison Research ◽  
Cement System ◽  
Cementitious System ◽  
Micro Morphology ◽  
Alkali Activated

An comparison research on the effect of pozzolanic reactions of fly ashes in architectural wastes recycle is described in the paper. In the experiment, NaOH and Na2SO4-Ca(OH)2 were used to activate the pozzolanic activities in the fly ashes—cement system to solidify the architectural wastes. The macro and micro testing methods were used to test the compressive strength, phase and electronic micro morphology of the hydration of alkali-activated fly ashes—cement cementitious system. The testing result shows that proper alkali-activated fly ashes—cement cementitious architectural wastes can shorten the incubation time of the pozzolanic reactions of fly ashes, whi ch make the reactions of fly ashes more sufficient. So the hydration products of fly ashes —cement cementitious system with alkali additions were more than those of without alkali add itions, and the compressive strength of the alkali-activated fly ashes—cement cementitious system is higher than that of non alkali-activated fly ashes—cement cementitious system.

Factors Influencing the Strength of Alkali-Activated Slag Cement

2011 ◽  
Vol 368-373 ◽  
pp. 3240-3245
Author(s):  
Zhi Jun Zhou ◽  
Hui Li ◽  
Qiang Song ◽  
Bao Jing Shen
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Water Glass ◽  
Slag Cement ◽  
Alkali Activated Slag ◽  
Factors Influencing ◽  
Activated Slag ◽  
Alkali Activated

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.

The Effect of Surfactant and Alkali on the Surface Tension of Simulated Solutions of Alkali Activated Slag Cement System

2011 ◽  
Vol 399-401 ◽  
pp. 1246-1250
Author(s):  
Xian Feng Liu ◽  
Jia Hui Peng ◽  
Chang Hui Yang ◽  
Yu Yan Shu ◽  
Da Chang Wu
Keyword(s):  
Surface Tension ◽  
Water Glass ◽  
High Viscosity ◽  
Heat Of Hydration ◽  
Slag Cement ◽  
Alkali Activated Slag ◽  
Cement System ◽  
Cement And Concrete ◽  
Activated Slag ◽  
Alkali Activated

Alkali activated slag cement and concrete are high strength, rapid hardening, low heat of hydration, good durability and so on. Whereas, too high viscosity and bad workability of the fresh mixture is the crux of the matter to embarrass application of alkali-activated slag cement and concrete. Development of special superplasticizer for alkali activated slag cement and concrete is a worth exploring way to solve the problem, and the study on the surface tension of simulated solutions of alkali activated slag cement system is one of the basic researches about the special superplasticizer. In this paper, the surface tension of surfactant-alkali-water was studied by Wilhelmy method. The results showed, first, water-glass had the best efficacity of several alkali activators, when the modulus of water-glass was 1.5 and dosage of water-glass by Na2O was 8%, the surface tension was reduced by 33 mN/m and reduced to 39.9mN/m; second, [CH3(CH2)9]2N(CH3)2Cl had the best efficacity of several surfactants, when the concentration of [CH3(CH2)9]2N(CH3)2Cl was 50g/L, the surface tension was reduced by 35.3 mN/m and reduced to 32.5 mN/m; finally, the effect of surfactant and alkali together on the surface tension of water was complex, surfactants had hardly effective in water glass.

Effect of Specimen Size and Curing Condition on the Compressive Strength of Alkali-Activated Concrete

2017 ◽  
Vol 2629 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Robert James Thomas ◽  
Sulapha Peethamparan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Specimen Size ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Slag Cement ◽  
Fly Ash Concrete ◽  
Activated Slag ◽  
Alkali Activated Concrete ◽  
Alkali Activated

Alkali-activated concrete is a rapidly emerging sustainable alternative to portland cement concrete. The compressive strength behavior of alkali-activated concrete has been reported by various studies to a limited extent, but these discussions have been based on minimal evidence. Furthermore, although it is known that specimen size has a distinct effect on the apparent compressive strength of concrete, this effect has yet to be modeled for alkali-activated concrete. This paper presents the results of a comprehensive study of the effects of curing condition (i.e., moist-cured at ambient temperature for 28 days or heat-cured at 50çC for 48 h) and specimen size on the compressive strength of sodium silicate–activated fly ash and slag cement concrete. The heat-cured strength of alkali-activated slag cement concrete was linearly related to the moist-cured strength; the former was about 5% greater than the latter. Heat curing also improved the strength of alkali-activated fly ash concrete, although the effect was greatly magnified for lower-strength mixtures and was much less significant at higher strengths. Existing size effect laws employed for portland cement concrete proved reasonably accurate in describing the effect of specimen size on the apparent strength of alkali-activated slag cement concrete. However, these existing models greatly underestimated the size effect in alkali-activated fly ash concrete; the authors suggest that this finding was the result of significant microcracking in the alkali-activated fly ash concrete.

Influence of New Type Water Reducer Agent YC on Properties of Alkali-Activated Slag Cement Mortar

2011 ◽  
Vol 374-377 ◽  
pp. 1357-1360
Author(s):  
Ke Chen ◽  
Chang Hui Yang ◽  
Ze Dong Yu ◽  
Qun Pan ◽  
Shuang Zhao
Keyword(s):  
Cement Mortar ◽  
Reduction Rate ◽  
Slag Cement ◽  
Alkali Activated Slag ◽  
Cement System ◽  
Influence Of Water ◽  
New Type ◽  
Type Water ◽  
Activated Slag ◽  
Alkali Activated

Through test on influence of water reducer agent YC on properties of alkali activated slag cement mortar, it is shown that water reducer agent YC has favorable plasticizing effect on alkali activated slag cement. When the alkali component is NaOH, the water reducer agent YC gives a water reduction rate of 22.0% to the alkali activated slag cement mortar and the flow ability loss with time is small. The water reducer agent can be adsorbed on the surface of slag and enhance theξpotential of the alkali activated slag cement system.

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