• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.166-171
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• 2014

This experimental study considers manufacturing method of the non-portland cement matrix for the light-weight building materials using blast furnace slag, paper ash, fly ash and polysilicon sludge the industrial by-product. For the experiment, we used paper ash by means of the foaming agent and alkali activator to make non-portland cement light-weight matrix. Various specimens were prepared with different types and addition ratios of the alkali activator. Then, the properties of these specimens were investigated by compressive strength test, bulk specific gravity. As a results, it was judged that experiment results of non-portland cement matrix with specific waste resources and alkali activators were useful as basic data for mixtures design and evaluation properties of lightweight non-portland cement building material.

• Journal of the Korean Ceramic Society
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• v.39 no.12
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• pp.1133-1137
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• 2002

The cement for solidification of the toxic waste was fabricated using a mixture of the waste concrete powder and blast furnace slag in the ratio of 1:1 and its hydrate morphology and compressive strength of the sample were evaluated in order to apply to the solidification of the COREX sludge. The X-ray diffraction analysis of the sample which prepared by the addition of 10% Portland cement and hemihydrate showed the presence of $Ca(OH)_2$, ettringite, gel-phase and C-S-H hydrate. Compressive strength of the sample exhibited enough high to use as a solidification cement. The strength of the sample was over 140 kgf/$m^2$ in 7 days in case of solidification of the COREX sludge and the sample possess sufficient morphology for the solidification and stabilization of the waste sludge.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.43-48
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• 2002

This study is experiment results that carried out the sulfuric acid immersion of the mortar containing blast furnace slag powder, based ell the mechanism of the sulfuric acid corrosion for concrete which was caused by the H$_2$S gas. The used materials is OPC, slag powder and gypsum, and the proportion of cement is total 13 levels which are 0~70% of the contents of slag, 0~6％ of the contents of gypsum. The specimen is immersed by 5% H$_2$SO$_4$ solution after 28 days and its weight loss is measured at intervals of 7 days. The results of experiment showed that the substitution ratio of 70% slag was excellent at a point of view for the sulfuric acid resistance and the sulfuric acid resistance was not improved by tile increase of the blaine of slag(8, 000longrightarrow10, 000$\textrm{cm}^2$/g) and the addition of gypsum.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.391-394
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• 2003

Effects of the polymer-binder ratio and slag content on the properties of combined wet/dry-cured polymer-modified mortars using granulated blast-furnace slag are examined. Results shows that the flexural, compressive, tensile and adhesion in tension strengths of polymer-modified mortar using the slag tend to increase with increasing slag content, and is inclined to increase with increasing polymer-binder ratio. In particular, the polymer-modified mortars with slag content of 40% provide about 20% higher tensile strength than unmodified mortars. Such high strength development is attributed to the high tensile strength of polymer and the improved bond between cement hydrates and aggregates because of the addition of polymer.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.353-354
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• 2009

The different sized slag powder, which have been used widely as a cement binder, was obtained by using 3 kind of mills. Two kinds of slag powder with different size was mixed and then investigated the relationship between the rheological properties and the particle packing ratio or particle distribution. It was found that the rheological properties of two mixed slag powder was proportional to the particle packing ratio of it. And the paste flowability of the mixed slag powder with wide particle distribution was very good.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.105-106
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• 2011

The present tests examined the resistance to freezing and thawing of alkail-activated (AA) slag concrete having compressive strength between 30~56 MPa. To enhance the compressive strength and resistance to freezing and thawing of AA slag concrete, Na ions were used for an activator. Test results revealed that the resistance to freezing and thawing of AA slag concrete is comparable to that of cement concrete when compressive strength is more than 50 MPa.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.112-118
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• 2012

Steel industry produces many by-products and wastes such as blast furnace slag, electric arc furnace slag, and converter slag. As in the case of rock, the main component of steel slag are CaO and $SiO_2$ ; further, steel slag is as alkaline as portland cement or concrete. Electric arc furnace oxidizing slag is possible to use as an aggregate for concrete ; however, it has been reclaimed because of it's expansibility caused by free CaO. Recently, a innovative rapid cooling method for melting steel slag has been developed in Korea, which reduces free lime content to minimum level and increases the stability of iron oxide. Therefore, this study describes the results of a series of research to utilize globular shape of electric arc furnace oxidizing slag fine aggregates made by rapidly cooled method for the construction industry by cooling rapidly melted slag from the steel industry. First of all, an experiment was carried out to investigate the quality characteristics of rapidly cooled electric arc furnace oxidizing slag fine aggregates in order to determine whether they can be applied to the construction industry. Then, by applying them to concrete of various particle sizes, we explored experimentally the desired condition to apply rapidly cooled electric arc furnace oxidizing slag fine aggregates to concrete.

• Journal of the Korea Concrete Institute
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• v.27 no.2
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• pp.95-102
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• 2015

In this paper, the effects of sodium hydroxide (NaOH) and aluminum potassium sulfate ($AlK(SO_4)_2{\cdot}12H_2O$) dosage on strength properties were investigated. For evaluating the property related to the dosage of alkali activator, sodium hydroxide (NaOH) of 4% (N1 series) and 8% (N2 series) was added to 1~5% (K1~K5) dosage of aluminum potassium sulfate ($AlK(SO_4)_2{\cdot}12H_2O$) and 1% (C1) and 2% (C2) dosage of calcium oxide (CaO). W/B ratio was 0.5 and binder/ fine aggregate ratio was 0.5, respectively. Test result clearly showed that the compressive strength development of alkali-activated slag cement (AASC) mortars were significantly dependent on the dosage of NaOH and $AlK(SO_4)_2{\cdot}12H_2O$. The result of XRD analysis indicated that the main hydration product of $NaOH+AlK (SO_4)_2{\cdot}12H_2O$ activated slag was ettringite and CSH. But at early ages, ettringite and sulfate coated the surface of unhydrated slag grains and inhibited the hydration reaction of slag in high dosage of $NaOH+AlK(SO_4)_2{\cdot}12H_2O$. The $SO_4{^{-2}}$ ions from $AlK(SO_4)_2{\cdot}12H_2O$ reacts with CaO in blast furnace slag or added CaO to form gypsum ($CaSO_4{\cdot}2H_2O$), which reacts with CaO and $Al_2O_3$ to from ettringite in $NaOH+AlK(SO_4)_2{\cdot}12H_2O$ activated slag cement system. Therefore, blast furnace slag can be activated by $NaOH+AlK(SO_4)_2{\cdot}12H_2O$.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.7
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• pp.801-809
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• 2007

Fly ash and blast furnace slag are an industrial by-product that can be alkali-activated to yield adhesive and cementitious materials, whose production is less energy-intensive and emits less $CO_2$ than ordinary Portland cement manufacture. A laboratory investigation was carried out to evaluate the effect of alkali-activating conditions on compressive strength of fly ash/slag cement and the acid corrosion resistance of this cement. Two alkali activator solution, NaOH and waterglass + NaOH solutions, were used. Waterglass concentration was the factor that gave the highest compressive strength in all tests. The next significant factor was the NaOH concentration, followed by curing temperature. Acid corrosion resistance of FC(fly ash cement) and FSC(fly ash/slag cement), such as sulfuric$(H_2SO_4)$ and hydrochloric acid(HCl), was for better than Portland cement(PC).

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.393-394
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• 2009

Recently, various researchers have studied alkali-activated concrete that do cementless as the binder. This study analyzed the effect on alkali-activated mortar by fineness of blast slag as the binder with no use of cement, by observing workability and compressive strength.