• Title, Summary, Keyword: organic admixtures

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The Effect of Cement Admixtures on Solidification of Tannery Sludge based Cement Method (피혁슬러지 고형화시 시멘트 혼화제의 영향)

  • 주소영;박상찬;전태성;손종렬;김태영
    • Journal of environmental and Sanitary engineering
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    • v.18 no.4
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    • pp.36-44
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    • 2003
  • The cement-based system among S/S(Solidification/Stabilization) is widely used to treat hazardous wastes. In this study, tannery sludge was solidified to evaluate the stabilization effects of using admixtures in the cement-based S/S. Fly ash as substitute also used to increase the strength of the S/S of hazardous waste. The compressive strength measurement and leaching experiment of chromium metal of solidified mortar were carried out to compare and evaluate the physical and chemical characteristics of solidified hazardous waste sludge. From the result of this study, there was increased of compressive strength by using AEW-3(early-hardening AE water reducing agent), and leaching concentration of chromium became low enough to satisfy the regulatory criteria. The successful solidification for the organic contaminant and heavy metal in hazardous waste should enable to treat by cement-based system using early-hardening AE water reducing admixture and fly ash as substituted cement.

The Physical Properties of Cement Containing Melamine-type Superplasticizer obtained Various Synthetic Conditions (다양한 합성조건에서 얻어진 멜라민계 고유동화제가 함유된 시멘트의 물리적 특성)

  • Yoon, Sung-Won;Shin, Kyoung-Ho
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.415-418
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    • 2005
  • Nowadays the three major commercially available of organic chemical admixtures are modified lignosulfonates(LS), sulfonated naphthalene-formaldehyde resins (SNF) and sulfonated melamine-formaldehye (SMF). In this study, various sulfonated melamine-formaldehyde (SMF) superplasticizers were synthesized via four synthetic steps. Hydroxymethylation (Step 1), Sulfonation (Step 2), Polymerization (Step 3) and Neutralization and Stabilization (Step 4). In this synthesis of SMF, reaction conditions such as the mole ratio of melamine to formaldehyde and the amount of acid catalyst were changed. After application of SMF superplasticizer to cement paste and mortar, the physical properties including workability, slump loss, compressive strength were compared.

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A Study on the Desulfurization Efficiency of Limestone Sludge with Various Admixtures

  • Seo, Sung Kwan;Chu, Yong Sik;Shim, Kwang Bo;Lee, Jong Kyu;Song, Hun
    • Journal of the Korean Ceramic Society
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    • v.52 no.6
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    • pp.479-482
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    • 2015
  • The flue gas desulfurization (FGD) process is one of the most effective methods to reduce the amount of $SO_2$ gas (up to 90%) generated by the use of fossil fuel. Limestone is usually used as a desulfurizing agent in the wet-type FGD process; however, the limestone reserves of domestic mines have become exhausted. In this study, limestone sludge produced from the steel works process is used as a desulfurizing agent. Seven different types of additives are also used to improve the efficiency of the desulfurization process. As a result, alkaline additive is identified as the least effective additive, while certain types of organic acids show higher efficiency. It is also observed that the amount of FGD gypsum, which is a by-product of the FGD process, increases with the used of some of those additives.

Synthesis and Application of Melamine-Type Superplasticizer at the Different Synthetic Conditions (멜라민계 고유동화제의 다양한 조건에서의 합성 및 응용)

  • Yoon Sung-Won;Shin Kyoung-Ho;Rho Jae-Seong
    • Journal of the Korea Concrete Institute
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    • v.17 no.5
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    • pp.811-818
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    • 2005
  • It is well known that the fluidity and the fluidity loss of fresh concrete are affected by the kind of organic admixtures. Organic admixture can improve the properties of concrete. Sulfonated Naphthalene-Formaldehyde(SNF) Superplasticizer is used representatively, but has a problem in fluidity loss. In this study, we synthesized the Sulfonated Melamine-Formaldehyde(SMF) superplasticizer at the various synthetic conditions and compared the physical properties with SMF superplasticizer. SW superplasticizer is synthesized with four synthetic steps. Step 1 is hydroxymethylation, Step. 2 is Sulfonation, Step. 3 is Polymerization and Step. 4 is Stabilization. Synthesis of SMF superplasticizer depends on pH, temperature and reaction time. In this reaction, we changed the mole ratio of melamine to formaldehyde at 1:3, 1:4, and the amount of acid catalyst at Step. 3. After application of SMF superplasticizer and its mixture with SNF superplasticizer to cement pastes and mortars, we measured the physical properties of them at the different dosages(0.5, 1.0, 1.5 wt%) to cement. All samples including superplasticizer showed higher compressive strengths and slump, smaller pore size and porosity than CEM

Analysis of the Characteristics of Manufactured Concrete, according to the Type of Admixture used when Remixing and Placing it (혼화제 종류별로 제조된 콘크리트의 재 혼합 타설시 특성 분석)

  • Ryu, Hyun-Gi;Shin, Sang-Yong
    • Journal of the Korea Institute of Building Construction
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    • v.10 no.5
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    • pp.95-102
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    • 2010
  • In recent years, the demand for the development of high quality and cost effective materials, as well as the competition to ensure a diverse and sufficient amount of ready-mixed concrete, has been increasing rapidly. In this experiment, concretes made with different admixtures are blended with each other in different combinations and ratios, in order to identify potential problems. The first test was a slump level test, in which all of the concretes met the required numbers, as they also did in the test for air content. Plain organic acid concrete scored the highest in bleeding amount, but organic acid mix in general showed a similar outcome. In the early measurement of compressive strength, plain naphthalene concrete was the strongest. Of the blends, the 5:5 mix of organic acid and naphthalene was the strongest. In the standard measurement, the 5:5 mix of naphthalene and lignin was the strongest. Tensile strength tests revealed similar results. Length change rate proved to be greater in blended concrete than in plain concrete, and dry shrinkage rate was highest in the 7:3 ratio blends. Through SEM photo analysis, it was confirmed that the 7:3 ratio blends contained more micro-voids. In conclusion, with the exception of a specific few combinations, it was found that the blending of different types of concrete is undesirable due to the delayed coagulation time as well as the early decrease in strength.

Effect of Excessive Addition of Organic Admixtures on the Properties of Concrete (콘크리트용 유기혼화제의 과잉첨가 효과)

  • 최재진;박원태;김기형;최연왕
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.631-637
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    • 1999
  • Effect of excessive addition of water reducing agent was examined by concrete tests. Water reducing agents of lignin or naphtalene base were used in the experiment. Setting of concrete was retarded according to the increase of dosage of water reducing agent and was extremely delayed at the 3 times or more use of lignin base agent and near 5 times or more use of naphtalene base agent respectively. When water reducing agent was used more than 6 times of standard dosage, early strength of concrete was very low and the strength reduction was very severe at all test ages in the concrete using lignin base agent.

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Effect of Carboxylic Acid on the Hydration of Plaster of Paris under Alkalinity (알카리성 분위기에서 소석고의 수화에 미치는 카르복실산의 영향)

  • 이승헌
    • Journal of the Korean Ceramic Society
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    • v.31 no.10
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    • pp.1107-1114
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    • 1994
  • Although various theories have been presented on the mechanism of setting retardation of plaster in addition to organic admixtures. The purpose of this paper is that Hydration studies of plaster of paris in the presence of carboxylic acids under alkalinity are examined in the coordination chemistry. Setting of plaster of paris is retarded by the addition of carboxylic acids except oxalic acid. And setting of plaster of paris contained 5 wt% of Ca(OH)2 is also retarded by the addition of above-mentioned carboxylic acids. The degree of retarding effect under alkalinity is found to be a function of the number of the functional group and the length of carbon chain of carboxyl acids. These reasons are attributed to the soluble complex formation, that is calcium complex formation between calcium ion and carboxylic acids. The author's proposal was confirmed by the results of electrical conductivity measurement. The formation of calcium complex was surpported by IR spectra.

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The Physical Fluidity Properties of Concrete Containing Melamine and Naphthalene-type Superplasticizer (멜라민계 및 나프탈렌계 고유동화제가 함유된 콘크리트의 물리적 유동특성)

  • Yoon, Sung-Won;Choi, Byoung-Wook
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.457-460
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    • 2008
  • It was predicted that the most recent technological developments in concrete technology rely on enhanced admixture efficiency rather than on improvement in cement manufacturing. Four major commercially available of organic chemical admixtures are modified lignosulfonates (LS), sulfonated naphthalene-formaldehyde resins (SNF), sulfonated melamine-formaldehyde resins(SMF) and polycarboxylate(PC). In this study, various sulfonated melamine-formaldehyde (SMF) superplasticizers were synthesized via four synthetic steps and reaction conditions such as the mole ratio of melamine to formaldehyde was changed. After application of SMF superplasticizer to cement concrete, the physical properties including workability, slump loss, compressive strength were compared with SNF

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Activating Temperature of Kaolin As a Cement Admixture

  • Park, Hee-Yong;Hwang, Hey-Zoo;Kim, Moo-Han;Kim, Moon-Han
    • KCI Concrete Journal
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    • v.13 no.1
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    • pp.3-9
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    • 2001
  • This research concerns the effect of kaolin as material of cement admixture. which has the advantage of low price and high adaptability. Kaolin, a kind of soil, is well known as a raw material of pottery. which is widely scat-tered on the earth (especially in Korea). This research shows the method and process for activating kaolin to have the properties of a cement admixture through experiment. In the experiments, kaolin is baked in high temperature and then cooled suddenly to be activated. The temperature zone and time span, on which kaolin is activated are examined. The research looks over the effect of the activated kaolin based on several criteria regarding to chemical and physical characteristic of general admixtures. The results of this research are as follows; kaolin start activation at the temperature above 50$0^{\circ}C$ and make ends of activation at the temperature below 95$0^{\circ}C$ and there was little effect by the change of duration. It is concluded that compressive strength can be increased by putting activated kaolin in the concrete and the activated kaolin is good for water resistance and anti-chemical , and that it is effective for protecting the leakage of hazardous article like Cl- and for protecting damage by an organic salt like acid. The activated kaolin of proper temperature and time is effective in compressive strength, salt resistance and acid resistance. The adaptability of activated kaolin as a cement admixture was shown through this research.

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Clean-up of Contaminated Groundwater by Permeable Reactive Barrier (투수성 반응벽에 의한 오염지하수 복원효과 분석)

  • 정하익;김상근
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.542-547
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    • 2000
  • It has become interested in the concept of permeable barriers for the containment and/or destruction of contaminated groundwater. The purpose of these trench-like barriers is to provide in situ capture and possibly destruction of the contaminant while preserving groundwater flow to uncontaminated zones. For instance, a trichloreethylene(TCE) plume may be contained by a permeable in which reactive iron reduces TCE to ethylene and ethane, compounds which can be easily biodegraded. The objective of this research is to examine the feasibility of using zero-valent iron as a clean-up media in permeable reactive barrier system. A series of laboratory column tests are performed. The concentration of influent and effluent water and the rate of clean up are analysed from these test results. The experimental result shows that the majority of the contamination in groundwater is removed in the reactor. And it shows the corresponding increase in the concentration of chloride ions through the reactor. Results from this study indicate that permeable reactive barrier containing admixtures of zero-valent iron and other materials can effectively clean up groundwater contaminated with organic compounds.

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