• Cement Symposium
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• no.28
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• pp.122-128
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• 2001

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.745-752
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• 2012

This paper studies the effect of the compressive strength for combined alkali-activated slag mortars. The effect of activators such as alkali type and dosage factor on the strength was investigated. The alkalis combinations made using five caustic alkalis (sodium hydroxide (NaOH, A series), calcium hydroxide ($Ca(OH)_2$, B series), magnesium hydroxide ($Mg(OH)_2$, C series), aluminum hydroxide ($Al(OH)_3$, D series), and potassium hydroxide (KOH, E series)) with sodium carbonate ($Na_2CO_3$) were evaluated. The mixtures were combined in different dosage at 1M, 2M, and 3M. The study results showed that the compressive strength of combined alkali-activated slag mortars tended to increase with increasing sodium carbonate. The strength of combined alkali-activated slag mortars was better than that of control cases (without sodium carbonate). The result from scanning electron microscopy (SEM) analysis confirmed that there were reaction products of calcium silicate hydrate (C-S-H) and alumina-silicate gels from combined alkali-activated slag specimens.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.525-528
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• 2006

감귤박을 원료로 하여 활성화제인 KOH를 사용한 약품활성화공정을 수행하여 감귤박-활성탄을 제조하고, 흡착능 및 세공분포 등을 분석한 결과 요오드 흡착능이 KS 규격 중 1급(활성탄 1,100 mg/g 이상)보다 높은 값으로 나타나 양질의 활성탄을 제조할 수 있음을 보였다. 또한 약품활성화법을 사용함으로써 탄화공정에서 제조된 탄화시료보다 월등히 높은 비표면적과 미세세공의 발달이 이루어져 KOH를 이용한 약품활성화법이 활성탄의 제조공정으로서 활용할 수 있음을 확인할 수 있었다.

• Journal of the Korean Geotechnical Society
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• v.29 no.4
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• pp.45-56
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• 2013

In this study, a blast furnace slag with latent hydraulic property is used to cement granular soils without using Portland cement. When the blast furnace slag reacts with an alkaline activator, it can cement soils. The effect of amounts of blast furnace slag and types of alkaline activator on soil strength was investigated for resource recycling. Four different amounts of slag and six different activators (two naturals and four chemicals) were used for preparing specimens. The specimens were air-cured for 3 or 7 days and then tested for unconfined compressive strength (UCS). The UCS of cemented sand with slag increased, in the order of specimens mixed with potassium carbonate, calcium hydroxide, sodium hydroxide and potassium hydroxide. Chemical alkaline activator was better than natural alkaline activator. The maximum UCS of 3-days cured specimens was 3 MPa for 16% of slag with potassium hydroxide, which corresponded to 37% of one with 16% of high-early strength portland cement. As the amount of slag increased, the UCS and dry density of a specimen increased for all alkaline activator cases. As the curing time increased from 3 days to 7 days, the UCS increased up to 97%. C-S-H hydrates were found in the cemented specimens from XRD analyses. Cement hydrates were more generated with increasing amount of slag and they surrounded sand particles, which resulted in higher density.

• Cement Symposium
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• no.25
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• pp.141-149
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• 1997

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2004.11a
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• pp.88-99
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• 2004

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2007.05a
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• pp.514-517
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• 2007

• Journal of the Korea Concrete Institute
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• v.27 no.3
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• pp.311-317
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• 2015

Cement zero concrete produced by alkali-activators and industrial by-products such as slag instead of cement, enables to solve the environmental pollution problems provoked by the exhaustion of natural resources and energy as well as the discharge of carbon dioxide. However, researches on the cement zero concrete are still limited to material studies and thus, study on the structural behavior of relevant members is essential to use the cement zero concrete as structural materials. This paper aims to evaluate experimentally and analytically the flexural behavior of RC beams using 50 MPa alkali activated slag concrete. To achieve such a goal, flexural tests on three types of RC beam specimens were conducted. A nonlinear analysis model is proposed using the modulus of elasticity and stress-strain relationship of alkali activated slag concrete. The analysis results obtained by the proposed model agree well with the experimental results, which could verify the validity of the proposed model.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.58-63
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• 2015

Several researches on cement zero concrete using alkali-activators have been conducted to investigate its fundamental material properties such as slump, strength and durability, however, research on the structural behavior of relevant members involving the elastic modulus, stress-strain relationship is essential for the application of this cement zero concrete to structural members. In this paper the shear behavior of reinforced concrete beams using 50 MPa-alkali activated slag concrete was experimentally evaluated. To achieve such a goal, six reinforced concrete beam specimens were fabricated and their shear behaviors were observed. The maximum difference between test results and analysis results in crack shear stress for beam specimens without stirrups is 31%, while that for beam specimens with stirrup is 15%. Furthermore, it is also found that the shear strength of alkali activated slag concrete is by 22~57% greater than the nominal shear strength calculated by design code, implying that shear design equations would provide conservative results on the safety side.

• The Journal of Engineering Research
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• v.4 no.1
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• pp.93-107
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• 2002

The active carbon waste which was used in water purification plant was investigated for the improvement of capillary after microwave treatment. The variation of surface area was measured with the various kinds and amounts of active carbon. The water vapor as the activator was verified to improve the capillary but it reacted with the water contained in waste active carbon. In contrast to the water vapor, the $CO_2$ gas improved the surface area about 10-20 % compared to as received one. The best results was observed at the intensity of 2.75 kw microwave. The more effective recovery of active carbon waste was observed at the microwave treatment compared to the rotary kiln treatment. However, the mass production is so difficult in the microwave process.