• Title/Summary/Keyword: 알칼리 활성화 슬래그 모르타르

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The Strength Properties of Alkali-Activated Slag Mortars by Combined Caustic Alkali with Sodium Carbonate as Activator (가성알칼리와 탄산나트륨을 혼합한 활성화제를 사용한 알칼리 활성화 고로슬래그 모르타르의 강도 특성)

  • Kim, Tae-Wan
    • 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.

Strength and Efflorescence Characteristics of Alkali-Activated Slag Cement Mortar with Red Mud according to Curing Conditions (양생조건에 따른 레드머드 혼입 알칼리활성화 슬래그 시멘트 모르타르의 강도 및 백화특성)

  • Kang, Suk-Pyo;Hwang, Byoung-Il
    • Journal of the Korea Institute of Building Construction
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    • v.18 no.3
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    • pp.267-275
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    • 2018
  • This study is to investigate the effect of various temperature and humidity conditions on the strength and efflorescence of alkali activated slag cement(AAS) using the red mud. As a result of examining the strength and efflorescence characteristics of AAS mixed with red mud according to the curing conditions, The compressive strength and flexural strength were the highest at 28 days, but the absorption rate, efflorescence area and soluble $Na^+$ elution were lowest in standard wet curing compared to the air curing, high temperature curing and low temperature curing.

Strength Development Properties of Alkali-Activated Slag Mortar by Autoclave Curing (오토클레이브 양생에 의한 알칼리활성슬래그 모르타르의 강도발현 특성)

  • Song, Jin-Gyu;Kim, Byeong-Jo;Oh, Myeong-hyeon
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2015.07a
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    • pp.218-219
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    • 2015
  • Precast concrete produced in the industry is advantage that easy to manage, and it save construction period in the field. The specimens according to the type of activator for AAS(Alkali-Activated Slag) mortar cured in an autoclave. The specimens of AAS mortar with sodium was shown the high rate of increase of the compressive strength.

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Pore and Efflorescence Characteristics of Alkali Activated Slag-Red Mud Cement Mortar depending on Red Mud Content (레드머드 대체율에 따른 알칼리활성화 슬래그-레드머드 시멘트 모르타르의 기공 및 백화특성)

  • Kang, Suk-Pyo;Kang, Hye-Ju
    • Journal of the Korea Institute of Building Construction
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    • v.17 no.3
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    • pp.261-268
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    • 2017
  • Red mud is an inorganic by-product obtained from the mineral processing of alumina from Bauxite ores. A highly alkali inorganic waste product with a pH level over 11, red mud in its original state negatively impacts the ecosystem, so appropriate treatment is necessary. The development of alkali activated slag-red mud cement can be a representative study aimed at recycling the strong alkali of the red mud as a construction material. However, Alkali-activated binders that use sodium activators have been reported to be more vulnerable to efflorescence. Therefore, in this study, the compressive strength, pore characteristics, water absorption, elution characteristics, and efflorescence properties of alkali-activated slag cement mortar were assessed according to their red mud substitution ratio.

Influence of Blended Activators on the Physical Properties of Alkali-activated Slag Mortar (알칼리 활성화 슬래그 모르타르의 특성에 미치는 혼합 활성화제의 영향)

  • Kim, Tae Wan;Park, Hyun Jae;Seo, Ki Young
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.16 no.6
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    • pp.26-33
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    • 2012
  • This paper reported on the effect of blended activator on the physical properties of alkali-activated slag mortar. Five different activators(caustic alkalis) were used: sodium hydroxide(NaOH, A Case), calsium hydroxide($Ca(OH)_2$, B Case), magnesium hydroxide($Mg(OH)_2$, C Case), aluminum hydroxide($Al(OH)_3$, D Case), and potassium hydroxide(KOH, E Case). We blended five caustic alkalis with sodium carbonate($Na_2CO_3$). The dosage of five caustic alkalis was 3M and sodium carbonate was 1M, 2M and 3M. The result of flow and setting time was decrease as the dosage of sodium carbonate increase. But the compressive strength was increase as the dosage of sodium carbonate increase. It was shown that there is a good effect of blended caustic alkalis with sodium carbonate in alkali-activated slag mortar.

Mechanical Properties of the Alkali-Activated Slag Mortar with Gypsum (석고를 혼합한 알칼리 활성화 슬래그 모르타르의 특성)

  • Kim, Tae Wan;Hahm, Hyung Gil
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.16 no.3
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    • pp.109-116
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    • 2012
  • This study investigated the effects of blast furnace slag mortars activated with sodium hydroxide(NaOH) and gypsum in relation to flow, setting time and compressive strength. The parameters in this studied was the gypsum ratio 0 to 50%, 3M and 6M of activator concentration and $20{\pm}2^{\circ}C$ and $35{\pm}2^{\circ}C$ of curing temperatures. The results of flow was increase, setting time was increase as the amount of gypsum increases. But the results of compressive strength was dependent on the gypsum ratio, indicating that the compressive strength increased with the increase of the amount of gypsum until a certain limit, beyond which the strength decreased quickly.

Effect of the Combined Using of Fly Ash and Blast Furnace Slag as Cementitious Materials on Properties of Alkali-Activated Mortar (결합재(結合材)로 플라이애시와 고로(高爐)슬래그의 혼합사용(混合使用)이 알칼리 활성(活性) 모르타르의 특성(特性)에 미치는 영향(影響))

  • Koh, Kyung-Taek;Kang, Su-Tae;Park, Jung-Jun;Ryu, Gum-Sung;Lee, Jang-Hwa;Kang, Hyun-Jin
    • Resources Recycling
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    • v.19 no.4
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    • pp.19-28
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    • 2010
  • Attempts to increase the utilization of a by-products such as fly ash and blast furnace slag to partially replace the cement in concrete are gathering momentum. But most of by-products is currently dumped in landfills, thus creating a threat to the environment. Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. However, most study deal only with alkali-activated blast furnace slag or fly ash, as for the combined use of the both, little information is reported. In this study, we investigated the influence of mixture ratio of fly ash/slag, type of alkaline activator and curing condition on the workability and compressive strength of mortar in oder to develop cementless alkali-activated concrete. In view of the results, we found out that the mixture ratio of fly ash/slag and the type of alkaline activator always results to be significant factors. But the influence of curing temperature in the strength development of mortar is lower than the contribution due to other factors. At the age of 28days, the mixture 50% fly ash and 50% slag activated with 1:1 the mass ratio of 9M NaOH and sodium silicate, develop compressive strength of about 65 MPa under $20^{\circ}C$ curing.

Strength and Pore Characteristics of Alkali-activated Slag-Red Mud Cement Mortar used Polymer According to Red Mud Content (레드머드 대체율에 따른 폴리머 혼입 알칼리활성화 슬래그-레드머드 시멘트모르타르의 강도 및 기공특성)

  • Kwon, Seung-Jun;Kang, Suk-Pyo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.2
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    • pp.26-33
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    • 2016
  • The alkali-slag-red mud(ASRC) cement belongs to clinker free cementitious material, which is made from alkali activator, blast-furnace slag(BFS) and red mud in designed proportion. This study is to investigate strength and pore characteristics of alkali-activated slag cement(NC), clinker free cementitious material, and ordinary portland cement(C) mortars using polymer according to red mud content. The results showed that the hardened alkali-activated slag-red mud cement paste was mostly consisted of C-S-H gel, being very fine in size and extremely irregular in its shape. So the hardened ASRC cement paste has lower total porosity, less portion of larger pore and more portion of smaller pore, as compared with those of hardened portland cement paste, and has higher strength within containing 10 wt.(%) of alkali-activated slag cement(NC) substituted by red mud.

Characteristics of Compressive Strength and Drying-shrinkage Equation of Alkali-activated Mortar (알칼리 활성화 결합재 모르타르의 압축강도 특성 및 건조수축 추정식에 관한 연구)

  • Park, Kwang-Min;Kim, Hyung-Suk;Cho, Young-Keun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.2
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    • pp.114-121
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    • 2017
  • The purpose of this study is to understand a compressive strength and propose a dry shrinkage strain equation being able to predict dry shrinkage of alkali-activated materials(AAM) mortar samples manufactured using fly-ash(FA) and ground granulated blast furnace slag(GGBFS). The main parameters investigated were the GGBFS replace ratios(30, 50, 70 and 100%) and sodium silicate modules(Ms[$SiO_2/Na_2O$] 1.0, 1.5 and 2.0). The compressive strength of AAM increased with increases GGBFS replace ratios or Ms contents. The dry shrinkage strain of AAM decreased with increases Ms contents. But, the dry shrinkage strain of AAM increased as the GGBFS replace ratio increases. Therefore, the GGBFS replace ratio seems to have very significant and important consequences for the mix design of the AAM mortar. The results indicated the R-square of single regression analysis based on each mix properties was the highest value; 0.7539~0.9786(average 0.9359). And the presumption equation of dry shrinkage strain with all variables(GGBFS, Ms and material age) has higher accuracy and its R-square was 0.8020 at initial curing temperature 23 degrees Celsius and 0.8018 at initial curuing temperature 70 degrees Celsius.

The Strength and Drying Shrinkage Properties of Alkali-Activated Slag Mortars as the Particle Size of Blended Fine Aggregate (혼합 잔골재의 입자 크기에 따른 알칼리 활성화 슬래그 모르타르의 강도와 건조수축 특성)

  • Kim, Tae Wan
    • Journal of the Korea Concrete Institute
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    • v.27 no.3
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    • pp.273-281
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    • 2015
  • In this paper, the performance of alkali-activated slag cement (AASC) is assessed in terms of compressive strength and drying shrinkage, using three different types of silica sand and river sand. The sand type has an important influence on the properties of AASC mortar. Three silica sands (SS1, SS2 and SS3) and river sand (RS) were considered. Three series of blended sands have been tested. A first series (S1) with RS and SS1, a second series (S2) with RS and SS2 and third series (S3) with RS and SS3 with a different blended ratios. The result shows a very significant influence of the blended sand on the AASC mortar properties. The compressive strength and drying shrinkage related with the particle sizes and blended ratios of sands are investigated considering blended sand properties like fineness modulus (FM) and relative specific surface. The type and blended ratio of sand seems to have very significant and important consequences for the mix design of the AASC mortar.