• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2003.11a
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• pp.1-8
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• 2003

변색목재의 화학적 성질을 조사한 결과, 처리전.후의 유기용매추출물 함량에 있어서 소나무재 및 리기다소나무재 공히 노화 및 변색균처리포 그 함량이 낮아지는 결과를 나타냈는바, fatty acids와 sterols 은 3주간 노화처리로 10.6-11.2%, 변색균처리로 36-41.1%의 높은 감소율을 나타냈다. triglycerides도 3주간 노화처리로 5.68-9.4%, 변색균처리로 38.5-40.0% 높은 감소율을 나타냈다. resin acids의 경우 3주간 노화처리로 6.1-11.3%, 변색균처리로 36-41.5%의 감소율을 나타냈다. 변색목재의 펄프화와 관련하여 소나무재 및 리기다소나무재의 크라프트펄프화결과, 알칼리펄프화에 비하여 펄프수율이 2-3% 높아졌다. 최적펄프화조건으로 활성알칼리농도 20%에서 펄프수율이 46.9-47.8%, reject율이 3.21-3.52%로 낮았다. 변색균처리한 목재도 활성알칼리 20%에서 펄프수율이 비교적 높은 43.5-45%를, reject율이 1.3-1.45%로서 변색균처리 모두에서 현저히 낮아짐을 알 수 있었다.

• 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.

• Cement
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• s.192
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• pp.39-47
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• 2011

최근 온실가스 감축과 기후변화 그리고 녹색성장에 대한 관심증대와 더불어 시멘트 분야의 연구 생산분야는 천연자원 사용량을 줄이고, 소성공정을 도입하지 않은 새로운 개념의 무기바인더가 다시 고개를 들고 있다. 다른 용어로는 비소성, 무시멘트 등으로 표현되기도 하는데, 광의의 개념으로 보면 알칼리 활성화제를 사용한 비소성 무기결합재인 지오폴리머가 바로 그것이다. 지오폴리머 결합재는 1957년 우크라이나의 토목공학회에서 개발한 알칼리 활성 슬래그시멘트에 기원을 두고 있고, 1970년대 말 프랑스의 다비도비치에 의해 지오폴리머라는 용어가 처음 사용되기 시작했다. 알칼리 활성 무기결합재(Alkali-activated inorganic binder)의 정의이다. Alkali-activated inorganic binder는 원래는 결합능력이 없던 재료에 대해서 Alkali-activating 용액을 첨가했을 때, 시멘트처럼 결합능력을 가지게 되는 모든 종류의 결합시스템을 말한다. 국내에도 이미 2000년 초부터 지오폴리머의 개념을 도입한 제품이 상업화되어 오랫동안 품질검증을 거쳐 안정성이 확인되고 있다. 최근에 다시 전남대가 그 동안의 연구성과를 발 빠르게 중소기업에 기술 이전하여 소위 무시멘트 시대에 진입하는 분위기이다. 지난 9월 동아에스텍(주)과 조인트벤처 설립을 위해 손을 잡았고, 사업화가 곧 진행될 것으로 보인다. 이를 계기로 국내에도 무시멘트회사가 본격적으로 등장하게 된 것이다. 따라서 본 고는 무시멘트의 개념을 잘 표현한 문헌으로 일본콘크리트공학 연차논문집, 2010년 1월호를 번역 요약 발췌한 것이다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.1
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• pp.58-66
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• 2013

This study investigated quality properties of alkali activated cement free mortar using industrial by-product such as cement kiln dust(CKD), silica fume(SF) and quartz sand powder(SP) to compare with previous research about blast furnace slag(BS) and fly ash(FA). The results were as following. All materials were effective to increase compressive strength, however they showed different tendency on flowability. CKD and SP increased flowability, but on the other hand SF did not because it's blain was great difference with other materials. Flowability and compressive strength were related with grading distributions of binders because CKD, SP and SF which had small particle size filled up BS and FA. Application of industrial by-products with various grading distributions could be effective for the high early strength and flowability of alkali activated cement free mortar using BS.

• Journal of the Korea Concrete Institute
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• v.24 no.5
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• pp.577-584
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• 2012

Carbonation resistance is one of the most influencing factors on durability of concrete. Alkali activated slag (AAS) is known to have weaker resistance for carbonation than OPC due to the low calcium contents. In this paper, the carbonation characteristic of AAS mortar which is related to the basicity (CaO/$SiO_2$) was investigated. In order to give the various basicity conditions, SM (source material) was blended with quicklime (CaO) and silicon dioxide ($SiO_2$) by adopting mechano-chemical treatment method. Experiments including flow test, compressive strength test, carbonation depth test, together with XRD, FTIR and TGA were employed to evaluate the effects of basicity of SM on the carbonation characteristics. The test results showed that the carbonation resistance effectively increased with the increase of the basicity of SM.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.25-26
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• 2011

The objective of this study is to develop the prototype system for microwave heating in a manufacture process of alkali activated Hwangtoh binder as replacement materials for the cement in concrete. In order to achieve this, four research phases are carried out as follows: 1) establishment of a system concept 2) deduction of a system element 3) design of the entire system 4) making of the prototype system for microwave heating.

• Journal of the Korea Concrete Institute
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• v.25 no.6
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• pp.657-665
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• 2013

The purpose of this study is the basic research of self-compacting concrete using Alkali-Activated Slag (AAS) binder in order to emphasize the durability of structures and facilitate casting the fresh concrete in field. The AAS binder emitted low carbon dioxide ($CO_2$) is eco friendly material of new concept because AAS products not only emit little $CO_2$ during production but also reuse the industrial by-products such as ground granulated blast-furnace slag (GGBS) of the steel mill. Until now, almost of domestic and foreign research are using Ordinary Portland Cement (OPC) for self-compacting concrete, and also, nonexistent research about AAS. The self-compacting concrete must get the performance of flowability, segregation resistance, filling and passing ability. Nine concrete mixes were prepared with the main parameter of unit amount of binder (400, 500, 600 $kg/m^3$) and 3 types of water-binder (W/B) ratio. The results of test were that fresh concretes were satisfied with flowability, segregation resistance, and filling ability of JSCE. But the passing ability was not meet the criteria of EFNARC because of higher viscosity of AAS paste than OPC. This high viscosity of AAS paste enables the manufacturing of self compacting concrete, segregation of which does not occur without the using of viscosity agent. It is necessary that the development of high fluidity AAS binders of higher strength and the study of better passing ability of AAS concrete mixes in order to use self compacting AAS concrete in field.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.389-390
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• 2010

this study is preliminary experimental research for develop methods to utilize the natural Hwangtoh as replacement materials for the cement in concrete, via alkali activation at $60^{\circ}C$ using NaOH solution and liquefied $Na_2SiO_3$ in a manufacture process of Hwangtoh concrete binder.

• 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.

• 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.