• Resources Recycling
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• v.21 no.3
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• pp.28-38
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• 2012

The purpose of this paper is to develop the alkali-activated concrete which uses 100% fly ash as a binder without any cement. The compressive strength of the mortar was examined depending on the chemical change in alkali-activator through SEM and SEM/EDS observations and the XRD analysis. It was found from the test that the higher molar concentration induced the greater effect on the initial strength, and that $Si^{4+}$ and $Al^{3+}$ were eluted relative to the compressive strength of mortar. In addition, it was confirmed that Al and Si were determined to be most influential ingredients on the microstructural development of the mortar, and that the different ingredient of the activator was almost no change in solidity from the XRD analysis.

• Journal of the Korea Concrete Institute
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• v.25 no.3
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• pp.261-269
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• 2013

In this study, it was developed eco-friendly inorganic binding material concrete using ground granulated blast furnace slag and alkali activator (water glass, sodium hydroxides). Eight reinforced concrete beam using inoganic binding material concrete were constructed and tested under monotonic loading. The major variables were mixture ratio of alkali activator, type of admixture and admixture. Experimental programs were carried out to improve and evaluate the flexural performance of such test specimens, such as the load-displacement, the failure mode, the maximum load carrying capacity, and ductility capacity. All the specimens were modeled in scale-down size. The eco-friendly concrete using inorganic binding material encouraged alkali activation reaction was rapidly hardening speed and showed possibility as a high strength concrete. Also, the RC beams using new materials showed similar behavior and failed similarly with RC beam used portland cement. It is thought that eco-friendly inorganic binding material concrete can be used with construction material and product as a basic research to replace cement concrete. If there is application to structures in PC member as well as production of 2nd concrete product, it could be improved the productivity and reduction of construction duration etc.

• Resources Recycling
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• v.15 no.4 s.72
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• pp.27-35
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• 2006

In order to use alunite as an activator of blast furnace slag, we studied the hydration characteristics of the calcined alunite and the ground blast furnace slag. The alunite calcined at $650{\cire}C$ consists of KAl($KAl(SO_{4})_{2}$ and $Al_{2}O_{3}$. The calcined alunite reacts with $Ca(OH)_{2}$ and gypsum to form etrringite ($3CaO{\cdot}Al_{2}O_{3}{\cdot}3CaSO_{4}{\cdot}32H_{2}O$) as fellows:$2KAl(SO_{4})_{2}+2Al_{2}O_{3}+13Ca(OH)_{2}+5CaSO_{4}{\cdot}2H_{2}O+73H_{2}O{\rightarrow}3(3CaO{\cdot}Al_{2}O_{3}{\cdot}3CaSO_{4}{\cdot}32H_{2}O)+2KOH$. The $SO_{4}^{2-}$ ions from calcined alunite reacts with CaO in blast furnace slag to from gypsum, which reacts with CaO and $Al_{2}O_{3}$ to from ettringite in calcined alunite-blast furnace slag system. Therefore blast furnace slag can be activated by calcined alunite.

• Resources Recycling
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• v.17 no.6
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• pp.68-78
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• 2008

Using a Pinus koraiensis and Pinus rigida which are normally being discarded in South Korea, optimal conditions of producing activated carbons have been studied to recycle as a higher value-added product. This study consists of two processes, the production process of charcoals from waste timbers by low temperature pyrolysis and the production process of activated carbons from the charcoals by chemical activation reaction. This paper deals with the production process of activated carbons from the charcoals by chemical activation reaction. As an alkali has been generally used as an activating agent, KOH and NaOH which react well with a carbon were used in this study. As a result of the experiments, it is confirmed that activated carbons made with KOH treatment had superior values in physicochemical properties to NaOH, showing that there was no remain of KOH at the surface of the charcoals while there was $3{\sim}4%$ of NaOH remaining after the experiments. Thus, it is concluded that KOH reacted more actively with a charcoal than NaOH. Moreover, it was also found that values in physicochemical properties when using a Pinus koraiensis are superior to the ones when using a Pinus rigida. The optimal mixing ratio of an activating agent to a charcoal was 400 wt.%. To improve the physicochemical properties, activated carbons were washed out by distilled water after neutralization with SM hydrochloric acid solution. When activated carbons were produced from a Pinus koraiensis in this optimal conditions, value of BET surface area was found to be approx. $2400\;m^2/g$.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.121-127
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• 2012

Cement has been traditionally used as a main binding material of high ductile fiber reinforced cementitious composites. The purpose of this paper is to investigate the feasibility of using alkali-activated slag and polyvinyl alcohol (PVA) fibers for manufacturing high ductile fiber reinforced cementless composites. Two mixture proportions with proper flowability and mortar viscosity for easy fiber mixing and uniform fiber dispersion were selected based on alkali activators. Then, the slump flow, compression, uniaxial tension and bending tests were performed on the mixes to evaluate the basic properties of the composites. The cementless composites showed an average slump flow of 465 mm and tensile strain capacity of approximately 2% of due to formation of multiple micro-cracks. Test results demonstrated a feasibility of manufacturing high ductile fiber reinforced composites without using cement.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.650-657
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• 2021

Alkali activators that stimulate mineral compounds are expensive materials, but in order to replace industrial products of high alkali in gredien ts, both product an d econ omic feasibility must be satisfied. In this study, alkali in dustrial waste(LW) from the LCD man ufacturin g process were used for the purpose of alkali active reaction of GGBFS for high stren gth concrete over 50MPa. Concrete mixed with LW had reduced workability, but it had the characteristic of increasing compressive strength. Analysis using ACI 209 Compressive Strength Model Equation was made to compare the changes in strength coefficients according to LW mixing. The durability test of concrete, such as Chloride Penetration Resistance and carbonation resistance, also showed excellent performance. In the Adiabatic temperature rise test results, the concrete mixed with LW had the effect of accelerating the initial hydration heat. However, the final Adiabatic temperature rise was not significantly affected by the mixing of LW.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.223-226
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• 2001

비닐에테르류의 비닐단량체는 ZnI$_2$ 존재하에서 HI와 같은 프로톤 산에 의해 양이온 리빙중합이 가능함이 보고된 바 있는데 이 때 프로톤산은 비닐에테르 단량체와 반응하여 adduct를 생성하고, ZnI$_2$는 adduct의 양이온중합 활성화제로 작용하는 것으로 알려져 있다. (중략)

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2007.11a
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• pp.49-50
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• 2007

• Applied Chemistry for Engineering
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• v.19 no.2
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• pp.168-172
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• 2008

Not all types of soil occurring on household fabrics can be removed by simple washing with normal surfactants. In order to achieve a satisfactory cleaning effect, an additional treatment step, called bleaching, is required in such cases. Currently, the best known bleach activator is tetraacetylethylenediamine (TAED). In this study, we synthesized a novel organic bleach activator (OBA), decanoyloxyethoxycarbonyloxybenzenesulfonate. For stabilizing the OBA, it was coated with zeolite and polyethylene glycol. It is found that the stability was enhanced and OBA shows good cleansing and bleaching effects even in cold water ($20^{\circ}C$). OBA also shows easy biodegradability with 88% in the condition of OECD standard. During the cleansing process, OBA shows excellent microbiological effect against T. mentagrophytes and S. aureus.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.555-556
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• 2009

The purpose of this study is to estimate compressive strength of concrete using granulated blast furnace slag. We used Sodium silicate, Potassium silicate, Barium hydroxide as alkali activators and Calcium hydroxide to develop water resistance.