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์•Œ์นผ๋ฆฌ ํ™œ์„ฑํ™” ์Šฌ๋ž˜๊ทธ ์‹œ๋ฉ˜ํŠธ, ์‚ฐํ™”์•Œ๋ฃจ๋ฏธ๋Š„, ๊ฐ•๋„, ๋ฏธ์„ธ๊ตฌ์กฐ
alkali-activated slag cement, aluminum oxide, strength, microstructure

  • 1. ์„œ ๋ก 

  • 2. ์‹คํ—˜๊ณ„ํš

  •   2.1 ์‚ฌ์šฉ์žฌ๋ฃŒ

  •   2.2 ๋ฐฐํ•ฉ ๋ฐ ์‹คํ—˜๋ฐฉ๋ฒ•

  • 3. ๊ฒฐ๊ณผ ๋ฐ ๊ณ ์ฐฐ

  •   3.1 ์œ ๋™์„ฑ(flow)

  •   3.2 ์••์ถ•๊ฐ•๋„

  •   3.3 ์ดˆ์ŒํŒŒ ์†๋„

  •   3.4 ๊ณต๊ทน๋ฅ 

  •   3.5 ๊ธธ์ด๋ณ€ํ™”

  •   3.6 SEM

  • 4. ๊ฒฐ ๋ก 

1. ์„œ    ๋ก 

์•Œ์นผ๋ฆฌ ํ™œ์„ฑํ™” ์Šฌ๋ž˜๊ทธ ์‹œ๋ฉ˜ํŠธ(alkali-activated slag cement; AASC)๋Š” ์ œ์ฒ ์†Œ ๋ถ€์‚ฐ๋ฌผ์ธ ์Šฌ๋ž˜๊ทธ ๋ฏธ๋ถ„๋ง์„ ์‚ฌ์šฉํ•œ ์‹œ๋ฉ˜ํŠธ๋กœ ๊ธฐ์กด์˜ ๋ณดํ†ตํฌํ‹€๋žœ๋“œ ์‹œ๋ฉ˜ํŠธ(Ordinary Portland cement; OPC)๋ฅผ ๋Œ€์ฒดํ•  ์นœํ™˜๊ฒฝ ๊ฑด์„ค์žฌ๋ฃŒ๋กœ ์ฃผ๋ชฉ๋ฐ›๊ณ  ์žˆ๋‹ค.1-2) ๊ตญ๋‚ด์™ธ ๋งŽ์€ ์—ฐ๊ตฌ์ž๋“ค์ด AASC์˜ ํŠน์„ฑ์„ ๋ฐํžˆ๊ธฐ ์œ„ํ•ด ๋‹ค์–‘ํ•œ ์—ฐ๊ตฌ์™€ ๊ฒฐ๊ณผ๋“ค์„ ๋ฐœํ‘œํ•˜๊ณ  ์žˆ๋‹ค. ํ˜„์žฌ๊นŒ์ง€์˜ ์—ฐ๊ตฌ๊ฒฐ๊ณผ์— ๋”ฐ๋ฅด๋ฉด AASC์˜ ํŠน์„ฑ์— ์˜ํ–ฅ์„ ์ฃผ๋Š” ์ธ์ž๋Š” ๋‹ค์–‘ํ•œ๋ฐ, ์˜ˆ๋ฅผ ๋“ค์–ด ๊ณ ๋กœ์Šฌ๋ž˜๊ทธ ๋ฏธ๋ถ„๋ง(ground granulated blast furnace slag; GGBFS)์˜ ๋ฌผ๋ฆฌ-ํ™”ํ•™์  ์„ฑ์งˆ, ์•Œ์นผ๋ฆฌ ํ™œ์„ฑํ™”์ œ์˜ ์ข…๋ฅ˜์™€ ๋†๋„, ๋ฐฐํ•ฉ๋ฐฉ๋ฒ•, ์–‘์ƒ์˜จ๋„์™€ ์–‘์ƒ๋ฐฉ๋ฒ•, ํ˜ผํ™”์ œ์˜ ์ข…๋ฅ˜, ํ˜ผํ™”์žฌ๋ฃŒ์˜ ํŠน์„ฑ ๋“ฑ ์—ฌ๋Ÿฌ ๊ฐ€์ง€๋กœ ์•Œ๋ ค์ ธ ์žˆ๋‹ค.1-5)

AASC์˜ ํŠน์„ฑ์— ์˜ํ–ฅ์„ ๋ฏธ์น˜๋Š” ์—ฌ๋Ÿฌ ์š”์ธ๋“ค ์ค‘์— GGBFS์˜ ํŠน์„ฑ์— ๊ด€ํ•œ ์—ฐ๊ตฌ๊ฐ€ ์ผ๋ถ€ ์—ฐ๊ตฌ์ž๋“ค์— ์˜ํ•ด ์ด๋ฃจ์–ด์กŒ๋‹ค. ์—ฐ๊ตฌ์ž๋“ค์€ GGBFS๋ฅผ ๊ตฌ์„ฑํ•˜๊ณ  ์žˆ๋Š” ์ฃผ์š” ์„ฑ๋ถ„๋“ค์˜ ๊ตฌ์„ฑ๋น„์™€ ๊ทธ์— ๋”ฐ๋ฅธ ๋ฐ˜์‘์ƒ์„ฑ๋ฌผ์— ์ฃผ๋ชฉํ•˜์˜€๋‹ค. ์ผ๋ถ€ ์—ฐ๊ตฌ์ž๋“ค์— ์˜ํ•ด์„œ GGBFS์˜ ๊ตฌ์„ฑ์„ฑ๋ถ„๋น„์— ๋Œ€ํ•œ ์ƒํ˜ธ ๊ด€๊ณ„๋ฅผ ๋ถ„์„ํ•œ ๊ฒฐ๊ณผ๊ฐ€ ๋‹ค์ˆ˜ ์žˆ์—ˆ๋‹ค. ์ตœ๊ทผ์—๋Š” Al2O3์˜ ํ•จ์œ ๋Ÿ‰์ด ๋‹ค๋ฅธ GGBFS๋“ค์„ ์‚ฌ์šฉํ•œ AASC์˜ ์ˆ˜ํ™” ํŠน์„ฑ์— ๊ด€ํ•œ ์—ฐ๊ตฌ๊ฐ€ ์žˆ์—ˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ์•„์ง๊นŒ์ง€ AASC์— ์žˆ์–ด์„œ Al2O3์˜ ํšจ๊ณผ์— ๊ด€ํ•œ ์—ฐ๊ตฌ๋Š” GGBFS ์ž์ฒด๊ฐ€ ๊ฐ€์ง€๊ณ  ์žˆ๋Š” Al2O3์˜ ์„ฑ๋ถ„์— ๊ด€ํ•œ ์—ฐ๊ตฌ๊ฐ€ ๋Œ€๋ถ€๋ถ„์ด๋‹ค.6-15)

๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” AASC์˜ ํŠน์„ฑ์— ์˜ํ–ฅ์„ ๋ฏธ์น˜๋Š” GGBFS์˜ ์˜ํ–ฅ์š”์ธ์— ๊ด€ํ•œ ๊ธฐ์ดˆ์—ฐ๊ตฌ๋กœ์„œ Al2O3์˜ ์™ธ๋ถ€ํ˜ผํ•ฉ์— ๋”ฐ๋ฅธ AASC์˜ ์—ญํ•™์  ํŠน์„ฑ์— ๊ด€ํ•œ ์—ฐ๊ตฌ์ด๋‹ค. ์ด๋Š” ๊ธฐ์กด์˜ GGBFS ์ž์ฒด๊ฐ€ ํ•จ์œ ํ•˜๊ณ  ์žˆ๋˜ Al2O3์— ๋Œ€ํ•œ ์˜ํ–ฅ์˜ ์—ฐ๊ตฌ๋ฅผ ๋ฒ—์–ด๋‚˜ ์™ธ๋ถ€์—์„œ ์ถ”๊ฐ€์ ์œผ๋กœ Al2O3๋ฅผ ํ˜ผํ•ฉํ•˜์—ฌ ๋‹ค์–‘ํ•œ Al2O3 ํ•จ์œ ๋Ÿ‰์„ ๊ฐ€์ง€๋Š” GGBFS๋ฅผ ๊ธฐ๋ฐ˜์œผ๋กœ ํ•˜๋Š” AASC์˜ ํŠน์„ฑ ํŒŒ์•…์„ ์œ„ํ•œ ๊ธฐ์ดˆ ์—ฐ๊ตฌ์ด๋‹ค. ์ด๋ฅผ ํ†ตํ•ด AASC์—์„œ Al2O3์˜ ์˜ํ–ฅ์„ ๊ฒ€ํ† ํ•˜๊ณ , AASC์˜ ๋ฐ˜์‘ ๋ฉ”์ปค๋‹ˆ์ฆ˜์˜ ํŒŒ์•…๊ณผ ์„ฑ๋Šฅํ–ฅ์ƒ์˜ ๊ธฐ์ดˆ์—ฐ๊ตฌ์ž๋ฃŒ๋กœ ํ™œ์šฉํ•˜๊ณ ์ž ํ•œ๋‹ค.

2. ์‹คํ—˜๊ณ„ํš

2.1 ์‚ฌ์šฉ์žฌ๋ฃŒ

๋ณธ ์—ฐ๊ตฌ๋ฅผ ์œ„ํ•ด ์‚ฌ์šฉํ•œ ๊ณ ๋กœ์Šฌ๋ž˜๊ทธ ๋ฏธ๋ถ„๋ง์€ ํฌํ•ญ์˜ K์‚ฌ ์ œํ’ˆ์„ ์‚ฌ์šฉํ•˜์˜€์œผ๋ฉฐ, ์„ฑ๋ถ„์€ XRF (X-ray fluorescence) ๋ถ„์„์„ ํ†ตํ•ด Table 1์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. GGBFS์˜ Si/Al ๋น„๋Š” 2.80, Ca/Al ๋น„๋Š” 3.28์ด๋ฉฐ ์—ผ๊ธฐ๋„(basicity) /Resources/kci/JKCI.2016.28.2.205/images/PICA941.gif=(CaO+MgO)/ (SiO2+Al2O3)๋Š” 0.92์ด๋‹ค.

Table 1 The chemical and physical properties of GGBFS

Chemical components (%)

SiO2

35.30

Al2O3

12.58

Fe2O3

0.79

CaO

41.30

MgO

3.19

TiO2

0.70

MnO

0.22

SO3

4.75

K2O

0.63

Physical properties

Ig-loss

0.34

Blain(m2/kg)

420

Density(g/mm3)

0.0028

์ž”๊ณจ์žฌ๋Š” ์กฐ๋ฆฝ๋ฅ (fineness modulus; FM) 2.61, ํ‘œ๋ฉด๊ฑด์กฐํฌํ™”์ƒํƒœ ๋ฐ€๋„ 0.0026g/mm3, ํก์ˆ˜์œจ์€ 1.25์ธ ๊ฐ•๋ชจ๋ž˜๋ฅผ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ์•Œ์นผ๋ฆฌ ํ™œ์„ฑํ™”์ œ๋Š” C์‚ฌ์˜ ์ˆ˜์‚ฐํ™”์นผ๋ฅจ(potassium hydroxide; KOH, purity > 98%)๊ณผ Al2O3 (purity > 96%)์ด๋‹ค. ๋ฐฐํ•ฉ์˜ ์ตœ์ € ์œ ๋™์„ฑ ํ™•๋ณด๋ฅผ ์œ„ํ•ด E์‚ฌ ํด๋ฆฌ๊ฐ€๋ฅด๋ณต์‹ค๊ณ„(polycarboxylate)์˜ ๊ณ ์„ฑ๋Šฅ ๊ฐ์ˆ˜์ œ(high-range water-reducing admixture)๋ฅผ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ๊ณ ์„ฑ๋Šฅ ๊ฐ์ˆ˜์ œ๋Š” ๋ฐ์€ ํ™ฉ์ƒ‰ ์•ก์ƒ(liquid)์œผ๋กœ, ๋น„์ค‘์€ 1.05ยฑ0.5 (20ยฐC์—์„œ)์ด๋‹ค.

2.2 ๋ฐฐํ•ฉ ๋ฐ ์‹คํ—˜๋ฐฉ๋ฒ•

Al2O3๋ฅผ ํ˜ผํ•ฉํ•œ AASC์˜ ํŠน์„ฑ์„ ์‚ดํŽด๋ณด๊ธฐ ์œ„ํ•ด Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์„ ๊ฒฐํ•ฉ์žฌ์ธ GGBFS ์ค‘๋Ÿ‰์— ๋Œ€ํ•ด 2~16%๊นŒ์ง€ 2%๋‹จ์œ„๋กœ ๋ชจ๋‘ 8์ข…๋ฅ˜์˜ ๋ฐฐํ•ฉ์„ ์„ ์ •ํ•˜์˜€๋‹ค. Al2O3๋ฅผ ํ˜ผํ•ฉํ•˜์ง€ ์•Š์€ ์‹œํ—˜์ฒด(control)๋„ ์ œ์ž‘ํ•˜์—ฌ Al2O3์— ์˜ํ•œ ํšจ๊ณผ๋ฅผ ๋น„๊ต ๊ฒ€ํ† ํ•˜๊ณ ์ž ํ•˜์˜€๋‹ค. ํ™œ์„ฑํ™”์ œ์ธ ์ˆ˜์‚ฐํ™”์นผ๋ฅจ(potassium hydroxide; KOH)์€ ๊ฐ•์•Œ์นผ๋ฆฌ์„ฑ ๋ฌผ์งˆ๋กœ ๊ตญ๋‚ด์™ธ ์„ ํ–‰์—ฐ๊ตฌ์—์„œ ๋‹ค์ˆ˜ ์‚ฌ์šฉ๋˜์—ˆ๋˜ ์žฌ๋ฃŒ๋กœ ์ˆ˜์‚ฐํ™”๋‚˜ํŠธ๋ฅจ(sodium hydroxide; NaOH)๊ณผ ์œ ์‚ฌํ•œ ์žฌ๋ฃŒ์ด๋‹ค. ๊ธฐ์กด์˜ ์—ฐ๊ตฌ๊ฒฐ๊ณผ๋“ค์„ ์ฐธ๊ณ ํ•˜์—ฌ KOH์˜ ๋†๋„๋Š” 2M (mole; M)๊ณผ 4M์˜ ๋‘ ๊ฐ€์ง€๋กœ ๊ณ ๋ คํ•˜์—ฌ KOH์˜ ๋†๋„ ์ฐจ์ด์— ๋”ฐ๋ฅธ ํŠน์„ฑ๋„ ํ•จ๊ป˜ ์‚ดํŽด๋ณด๊ณ ์ž ํ•˜์˜€๋‹ค.

๋ชจ๋ฅดํƒ€๋ฅด์˜ ๋ฐฐํ•ฉ์€ ์ค‘๋Ÿ‰๋น„๋กœ ๊ณ ๋กœ์Šฌ๋ž˜๊ทธ ๋ฏธ๋ถ„๋ง : ์ž”๊ณจ์žฌ๋Š” 1.0 : 2.0์œผ๋กœ ํ•˜์˜€๊ณ , ๋ฌผ/๊ฒฐํ•ฉ์žฌ(W/B) ๋น„๋Š” 0.5์ด๋‹ค. ๋ฐฐํ•ฉ ์š”์†Œ๋Š” Table 2์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

Table 2 Mixture properties of AASC mortar

Content ratio by binder weight(%)

Dosage of KOH

Al2O3

GGBFS

2M or 4M

0

100

2

98

4

96

6

94

8

92

10

90

12

88

14

86

16

84

๊ฐ๊ฐ์˜ ๋ฐฐํ•ฉ์— ๋”ฐ๋ผ ์žฌ๋ฃŒ๋ฅผ ํ˜ผํ•ฉํ•œ ํ›„ KS L 5109 (์ˆ˜๊ฒฝ์„ฑ ์‹œ๋ฉ˜ํŠธ ํŽ˜์ด์ŠคํŠธ ๋ฐ ๋ชจ๋ฅดํƒ€๋ฅด์˜ ๊ธฐ๊ณ„์  ํ˜ผํ•ฉ ๋ฐฉ๋ฒ•)์— ๋”ฐ๋ผ ๋ฐฐํ•ฉํ•˜์˜€๋‹ค. ์œ ๋™์„ฑ ์‹œํ—˜์€ KS L 5111 (์‹œ๋ฉ˜ํŠธ ์‹œํ—˜์šฉ ํ”Œ๋กœ ํ…Œ์ด๋ธ”)๋ฐฉ๋ฒ•์— ๋”ฐ๋ผ ์‹œํ–‰ํ•˜์˜€๋‹ค. ์••์ถ•๊ฐ•๋„์˜ ์ธก์ •์€ 50ร—50ร—50mm ๋ชฐ๋“œ์— ํƒ€์„คํ•˜์—ฌ ์ƒ๋Œ€์Šต๋„(relative humidity; RH) 75ยฑ5%, 23ยฑ2ยฐC์˜ ํ•ญ์˜จํ•ญ์Šต๊ธฐ์— ๋„ฃ๊ณ  1์ผ(24h) ํ›„ ๋ชฐ๋“œ๋ฅผ ํƒˆํ˜•ํ•˜์˜€๋‹ค. ๋ชฐ๋“œ ํƒˆํ˜• ํ›„ ์••์ถ•๊ฐ•๋„ ์ธก์ • ์žฌ๋ น์ผ๊นŒ์ง€ RH 75ยฑ5%, 23ยฑ2ยฐC์˜ ํ•ญ์˜จํ•ญ์Šต๊ธฐ์— ๋ณด๊ด€ํ•˜์˜€๋‹ค. ๊ธธ์ด๋ณ€ํ™” ์ธก์ •์šฉ ์‹œํ—˜์ฒด๋Š” ASTM C490 (Standard Practice for Use of Apparatus for the Determination of Length Change of Hardened Cement Paste, Mortar, and Concrete) ๊ทœ์ •์˜ 25ร—25ร—285mm๋ฅผ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ๊ฑด์กฐ์ˆ˜์ถ• ์ธก์ •์€ ASTM C596 (Standard Test Method for Drying Shrinkage of Mortar Containing Hydraulic Cement)์— ์ œ์‹œ๋œ ๋ฐฉ๋ฒ•์— ๋”ฐ๋ผ ์ˆ˜ํ–‰ํ•˜์˜€์œผ๋ฉฐ, ์‹œํ—˜์ฒด๋Š” RH50ยฑ5%, 20ยฑ2ยฐC์˜ ํ™˜๊ฒฝ์— 91์ผ๊นŒ์ง€ ๋ณด๊ด€ํ•˜์˜€๋‹ค. ์••์ถ•๊ฐ•๋„์˜ ์ธก์ •์€ ๊ฐ ์ธก์ • ์žฌ๋ น(1, 3, 7 ๋ฐ 28์ผ)์—์„œ 3๊ฐœ์˜ ์‹œํ—˜์ฒด์— ๋Œ€ํ•ด ์‹œํ—˜์„ ์ˆ˜ํ–‰ํ•˜๊ณ  ๊ทธ ํ‰๊ท ๊ฐ’์„ ์‚ฌ์šฉํ•˜์˜€๋‹ค.

์ดˆ์ŒํŒŒ์†๋„(ultrasonic pulse velocity; UPV)๋Š” PROCEQ CCT-4๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ์ธก์ •ํ•˜์˜€๋‹ค. ์ดˆ์ŒํŒŒ ์†๋„ ์ธก์ •๋ฐฉ๋ฒ•์€ ์‹œํ—˜์ฒด์˜ ์˜ค๋ฅธ์ชฝ์— ๋ฐœ์ง„์ž๋ฅผ, ์™ผ์ชฝ์— ์ˆ˜์‹ ์ž๋ฅผ ๋‘๊ณ  ์†๋„๋ฅผ ์ธก์ •ํ•œ ๋‹ค์Œ ๋™์ผ ์‹œํ—˜์ฒด์— ๋Œ€ํ•ด ์˜ค๋ฅธ์ชฝ์— ์ˆ˜์‹ ์ž๋ฅผ ์™ผ์ชฝ์— ๋ฐœ์ง„์ž๋ฅผ ๋‘๊ณ  ์ธก์ •ํ•˜๋Š” ๋ฐฉ์‹์œผ๋กœ ์„œ๋กœ ๊ต๋Œ€๋กœ ์ธก์ •ํ•œ ๊ฐ’์˜ ํ‰๊ท ์„ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ์ด ๊ณต๊ทน๋ฅ ์€ ์žฌ๋ น 28์ผ ์‹œํ—˜์ฒด์— ๋Œ€ํ•ด ASTM C642 (Standard Test Method for Density, Absorption, and Void in Hardened Concrete)์— ๋”ฐ๋ผ ์‹คํ—˜ํ•˜์—ฌ ์ธก์ •ํ•˜์˜€๋‹ค.

SEM (Scanning electron microscopy)์€ HITACHI FE-SEM S-4700 ์žฅ๋น„๋ฅผ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ์ธก์ • ์‹œํŽธ์€ ๊ฐ•๋„ ํŠน์ • ํ›„ ํŒŒ์‡„๋œ ์‹œํ—˜์ฒด ์กฐ๊ฐ์„ ์ฑ„์ทจํ•˜์—ฌ ์•„์„ธํ†ค์— 48์‹œ๊ฐ„ ์นจ์ง€์‹œ์ผœ ์ˆ˜ํ™”์ •์ง€์‹œํ‚จ ๋‹ค์Œ ์˜จ๋„ 35ยฑ5ยฐC, ์ƒ๋Œ€์Šต๋„ โ‰ค 50%์˜ ๊ฑด์กฐ๊ธฐ์—์„œ 48์‹œ๊ฐ„ ๊ฑด์กฐ์‹œํ‚จ ํ›„ ์ธก์ •์„ ์ค€๋น„ํ•˜์˜€๋‹ค. ๋˜ํ•œ ๊ด€์ฐฐ ์‹œํ—˜์ฒด์— ๋Œ€ํ•ด energy dispersive X-ray spectroscopy (EDX)๋ฅผ ์ˆ˜ํ–‰ํ•˜์—ฌ ๋ฐ˜์‘์ƒ์„ฑ๋ฌผ์งˆ์˜ ๊ตฌ์„ฑ์š”์†Œ์— ๋Œ€ํ•œ ๋ถ„์„์„ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. XRD ์‹œํ—˜์šฉ ๋ถ„๋ง๋„ ๊ฐ•๋„ ์ธก์ •ํ›„ ํŒŒ์‡„๋œ ์‹œํŽธ์„ ์ˆ˜ํ™”์ •์ง€ ์‹œํ‚จ ํ›„ ๋ถ„์‡„ํ•˜์—ฌ No.200์ฒด๋ฅผ ํ†ต๊ณผํ•˜๋Š” ์‹œ๋ฃŒ๋ฅผ ๋ถ„์„ํ•˜์˜€๋‹ค.

3. ๊ฒฐ๊ณผ ๋ฐ ๊ณ ์ฐฐ

3.1 ์œ ๋™์„ฑ(flow)

๋ณธ ์—ฐ๊ตฌ์— ๊ณ ๋ ค๋œ ๋ชจ๋ฅดํƒ€๋ฅด์˜ ์œ ๋™์„ฑ์€ ์„ ํ–‰ ์˜ˆ๋น„์‹คํ—˜, ๋ณธ ์—ฐ๊ตฌ์˜ ๋ชฉ์ ๊ณผ ์‹œํ—˜์ฒด ์ œ์กฐ ๋“ฑ์„ ์ข…ํ•ฉ์ ์œผ๋กœ ๊ณ ๋ คํ•˜์—ฌ ์ตœ์ € ์œ ๋™์„ฑ์„ 160mm๋กœ ์ •ํ•˜์˜€๋‹ค. ๋ชจ๋“  ๋ฐฐํ•ฉ์€ ์ตœ์†Œ 160ยฑ10mm์˜ ์œ ๋™์„ฑ์„ ํ™•๋ณดํ•˜๋„๋ก ๊ณ ์„ฑ๋Šฅ ๊ฐ์ˆ˜์ œ์˜ ์–‘์„ ์กฐ์ ˆํ•˜์˜€๋‹ค. ๊ฐ ์‹œํ—˜์ฒด์˜ ์œ ๋™์„ฑ๊ณผ ์‚ฌ์šฉ๋œ ๊ณ ์„ฑ๋Šฅ ๊ฐ์ˆ˜์ œ์˜ ์–‘์€ Fig. 1์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์œ ๋™์„ฑ์ด ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด์—ˆ๊ณ , ์ด์—๋”ฐ๋ผ ์ตœ์†Œ ์œ ๋™์„ฑ์„ ํ™•๋ณดํ•˜๊ธฐ ์œ„ํ•œ ๊ณ ์„ฑ๋Šฅ ๊ฐ์ˆ˜์ œ์˜ ์ฒจ๊ฐ€๋Ÿ‰๋„ ์ฆ๊ฐ€ํ•˜๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ํŠนํžˆ 2M KOH ์‹œํ—˜์ฒด๋“ค๋ณด๋‹ค 4M KOH ์‹œํ—˜์ฒด๋“ค์˜ ์œ ๋™์„ฑ์ด ์ƒ๋Œ€์ ์œผ๋กœ ๊ฐ์†Œํ•˜๊ณ  ์žˆ๋Š”๋ฐ, ์ด๋Š” ์ƒ๋Œ€์ ์œผ๋กœ ๋†’์€ ํ™œ์„ฑํ™”์ œ์˜ ๋†๋„๊ฐ€ GGBFS์˜ ํ™œ์„ฑํ™”๋ฅผ ์ด‰์ง„์‹œํ‚ค๊ณ  ์ˆ˜ํ™”๋ฐ˜์‘์„ ์ฆ๋Œ€์‹œ์ผœ ์‘๊ฒฐ ์ž‘์šฉ๊ณผ ๋ฐ˜์‘์ƒ์„ฑ๋ฌผ์งˆ์˜ ์ƒ์„ฑ์„ ๊ฐ€์†ํ™”ํ•˜๊ธฐ ๋•Œ๋ฌธ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

/Resources/kci/JKCI.2016.28.2.205/images/Figure_CONCRETE_28_2_09_F1.jpg

Fig. 1 Flow and admixture contents

3.2 ์••์ถ•๊ฐ•๋„

Fig. 2๋Š” Al2O3 ํ˜ผํ•ฉ๋ฅ ์— ๋”ฐ๋ฅธ ์••์ถ•๊ฐ•๋„ ๊ฒฐ๊ณผ๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค. 2M์™€ 4M KOH ๋†๋„ ๋ชจ๋‘ Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์••์ถ•๊ฐ•๋„๋„ ์ฆ๊ฐ€ํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ๋‹ค. 28์ผ ์••์ถ•๊ฐ•๋„์— ๋Œ€ํ•ด ์‚ดํŽด๋ณด๋ฉด 2M KOH์—์„œ ์ตœ๊ณ ๊ฐ•๋„๋Š” 16% Al2O3 ํ˜ผํ•ฉ ์‹œํ—˜์ฒด์—์„œ 30.8MPa์ด๊ณ , 4M KOH์˜ ๊ฒฝ์šฐ 16% Al2O3 ํ˜ผํ•ฉ ์‹œํ—˜์ฒด์—์„œ 45.2MPa์˜ ์••์ถ•๊ฐ•๋„๋ฅผ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

/Resources/kci/JKCI.2016.28.2.205/images/Figure_CONCRETE_28_2_09_F2.jpg

Fig. 2 Compressive strength of different Al2O3 contents and dosage of KOH

Table 3์€ Al2O3๋ฅผ ํ˜ผํ•ฉํ•˜์ง€ ์•Š์€ ์‹œํ—˜์ฒด(control)์™€ Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์— ๋”ฐ๋ฅธ 28์ผ ์••์ถ•๊ฐ•๋„ ๊ฐ’์˜ ์ƒ๋Œ€์  ๋ณ€ํ™”์œจ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค. Table 3์—์„œ, 2M๊ณผ 4M KOH ๋†๋„ ๋ชจ๋‘ Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์ƒ๋Œ€์ ์ธ ๊ฐ•๋„์ฆ๊ฐ€์œจ๋„ ์ ์ฐจ ์ฆ๊ฐ€ํ•˜๊ณ  ์žˆ์—ˆ๋‹ค.

Table 3 Relative compressive strength at age 28 days

Al2O3 

Contents(%)

Relative strength ratio (%)

2M KOH solution

4M KOH solution

2

5.69

2.23

4

6.16

6.69

6

8.53

9.24

8

10.90

12.10

10

16.59

18.47

12

28.91

25.80

14

41.71

38.22

16

45.97

43.95

S. Barbuhuiya11) ๋“ฑ์€ nano-Al2O3๋ฅผ 0%, 2%, ๊ทธ๋ฆฌ๊ณ  4% ์น˜ํ™˜ํ•œ OPC paste์˜ ๊ฐ•๋„ ํŠน์„ฑ์— ๊ด€ํ•œ ์—ฐ๊ตฌ์—์„œ nano-Al2O3์˜ ์น˜ํ™˜์€ ๊ฐ•๋„ํ–ฅ์ƒ์— ์˜ํ–ฅ์„ ๋ฏธ์น˜์ง€ ์•Š๋Š”๋‹ค๊ณ  ํ•˜์˜€๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ Al2O3์˜ ์‚ฌ์šฉ์€ ์‹œํ—˜์ฒด์˜ ์กฐ์ง์„ ์น˜๋ฐ€ํ•˜๊ฒŒ ๋งŒ๋“ ๋‹ค๊ณ  ์–ธ๊ธ‰ํ•˜์˜€๋‹ค. K.L. Lin12) ๋“ฑ์€ OPC์™€ GGBFS์˜ ํ˜ผํ•ฉ ์‹œ๋ฉ˜ํŠธ๊ณ„์—์„œ Al2O3์˜ ์–‘์ด ์ฆ๊ฐ€ํ•˜๋ฉด ์ดˆ๊ธฐ๊ฐ•๋„๋Š” ์ฆ๊ฐ€ํ•˜์ง€๋งŒ ์ผ์ •์ˆ˜์ค€์˜ Al2O3 ์–‘์„ ์ดˆ๊ณผํ•˜๋ฉด ์žฅ๊ธฐ๊ฐ•๋„๋Š” ๊ฐ์†Œํ•˜๋Š” ๊ฒฐ๊ณผ๋ฅผ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

A.R. Sakulich13) ๋“ฑ์€ Al2O3์˜ ํ•จ์œ ๋Ÿ‰์ด ์„œ๋กœ ๋‹ค๋ฅธ GGBFS์™€ ํ™œ์„ฑํ™”์ œ๋กœ NaOH/waterglass๋ฅผ ์‚ฌ์šฉํ•œ AASC์—ฐ๊ตฌ์—์„œ ์†Œ๋Ÿ‰์˜ Al2O3๋Š” ๊ฐ•๋„ํ–ฅ์ƒ์— ๊ธ์ •์ ์ด์ง€๋งŒ ๋‹ค๋Ÿ‰์˜ Al2O3๋ฅผ ํ•จ์œ ํ•œ ๊ฒฝ์šฐ๋Š” ๊ฐ•๋„ํ–ฅ์ƒ์„ ์˜ˆ์ธกํ•  ์ˆ˜ ์—†๋‹ค๊ณ  ํ•˜์˜€๋‹ค. R. Tanzer14) ๋“ฑ์€ Al2O3์˜ ํ•จ์œ ๋Ÿ‰์ด ์„œ๋กœ ๋‹ค๋ฅธ GGBFS๋ฅผ NaOH์™€ potassium silicate solutions์œผ๋กœ ๊ฐ๊ฐ ํ™œ์„ฑํ™”ํ•œ ์‹คํ—˜์—์„œ Al2O3์˜ ํ•จ๋Ÿ‰์ด ์ฆ๊ฐ€ํ• ์ˆ˜๋ก NaOH์— ์˜ํ•ด ํ™œ์„ฑํ™”๋œ ์Šฌ๋ž˜๊ทธ์˜ ๊ฐ•๋„๊ฐ€ ๋” ํ–ฅ์ƒ๋˜์—ˆ๋‹ค๊ณ  ํ•˜์˜€๋‹ค. M.B. Haha15) ๋“ฑ์€ ์„œ๋กœ ๋‹ค๋ฅธ Al2O3์˜ ํ•จ๋Ÿ‰์„ ๊ฐ€์ง€๋Š” GGBFS๋ฅผ NaOH์™€ sodium silicate solution (waterglass; WG)์œผ๋กœ ํ™œ์„ฑํ™”์‹œํ‚จ AASC์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๋ฅผ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. ๊ทธ๊ฒฐ๊ณผ Al2O3์˜ ํ•จ๋Ÿ‰์ด ์ฆ๊ฐ€ํ• ์ˆ˜๋ก GGBFS์˜ ์ˆ˜ํ™”์œจ์€ ์ฒœ์ฒœํžˆ ๊ฐ์†Œํ•˜์˜€๊ณ  Al2O3์˜ ํ•จ๋Ÿ‰์ด ๋†’์„์ˆ˜๋ก ์ดˆ๊ธฐ๊ฐ•๋„๋Š” ๋‚ฎ๋‹ค๋Š” ์‚ฌ์‹ค์„ ์–ธ๊ธ‰ํ•˜์˜€๋‹ค.

๊ธฐ์กด์˜ ์—ฐ๊ตฌ๊ฒฐ๊ณผ๋“ค๊ณผ ๋น„๊ตํ•ด ๋ณผ ๋•Œ, GGBFS ์ž์ฒด๊ฐ€ ํ•จ์œ ํ•œ Al2O3์˜ ํ•จ๋Ÿ‰์— ๋”ฐ๋ฅธ ํŠน์„ฑ๊ณผ ๋‹ฌ๋ฆฌ ๋ณธ ์—ฐ๊ตฌ์—์„œ ๊ณ ๋ คํ•œ ๊ฒƒ์ฒ˜๋Ÿผ ์ถ”๊ฐ€์ ์œผ๋กœ ์™ธ๋ถ€์—์„œ Al2O3๋ฅผ ์ฒจ๊ฐ€ํ•  ๊ฒฝ์šฐ ์ดˆ๊ธฐ๊ฐ•๋„ ์ €ํ•˜ ๋“ฑ์€ ๋ฐœ์ƒํ•˜์ง€ ์•Š์•˜๋‹ค. ๋˜ํ•œ ๊ฐ•๋„ํ–ฅ์ƒ์— ์˜ํ–ฅ์„ ๋ฏธ์น˜๋Š” Al2O3์˜ ํ•จ๋Ÿ‰์˜ ์ตœ์ ๋ฒ”์œ„๋Š” ๋ฐœ๊ฒฌ๋˜์ง€ ์•Š์•˜๊ณ  Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ๊ฐ•๋„๋„ ์ฆ๊ฐ€ํ•˜๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ์ด๋Š” GGBFS๊ฐ€ ์ž์ฒด์ ์œผ๋กœ ํ•จ์œ ํ•œ Al2O3์˜ ๊ฒฝ์šฐ ํ™œ์„ฑํ™”์ œ์— ์˜ํ•ด GGBFS์— ํ•จ์œ ๋˜์–ด ์žˆ๋Š” Al2O3 ์„ฑ๋ถ„์˜ ์šฉ์ถœ๊นŒ์ง€ ์‹œ๊ฐ„์ด ๊ฑธ๋ฆฌ๊ณ , ์šฉ์ถœ๋œ Al2O3 ์„ฑ๋ถ„์ด ๋ฐ˜์‘์ƒ์„ฑ๋ฌผ์งˆ์„ ๋งŒ๋“œ๋Š”๋ฐ ๊ด€์—ฌํ•˜๋Š” ์ •๋„ ๋“ฑ์— ๋”ฐ๋ผ ๋ณธ ์—ฐ๊ตฌ ๊ฒฐ๊ณผ์™€ ๋‹ค๋ฅธ ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

3.3 ์ดˆ์ŒํŒŒ ์†๋„

UPV๋Š” ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ๋‚ด๋ถ€ ์ƒํƒœ๋ฅผ ๊ฐœ๋žต์ ์ด๊ณ  ๊ฐ„ํŽธํ•˜๊ฒŒ ์ถ”์ •ํ•˜๋Š”๋ฐ ์‚ฌ์šฉ๋Š” ์ผ๋ฐ˜์ ์ธ ์‹œํ—˜๋ฐฉ๋ฒ• ์ค‘ ํ•˜๋‚˜์ด๋‹ค.

Fig. 3์€ 28์ผ ์žฌ๋ น์—์„œ์˜ ๊ฐ ์‹œํ—˜์ฒด๋ณ„ UPV๋ฅผ ์ธก์ •ํ•œ ๊ฒƒ์ด๋‹ค. UPV๋Š” KOH์˜ ๋†๋„์™€ ๊ด€๊ณ„์—†์ด Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์ฆ๊ฐ€ํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์ด๋Ÿฌํ•œ ๊ฒฐ๊ณผ๋Š” Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ• ์ˆ˜๋ก ๋ฐ˜์‘์ƒ์„ฑ๋ฌผ์งˆ์˜ ์–‘์ด ์ฆ๊ฐ€ํ•˜์—ฌ ์ƒ๋Œ€์ ์œผ๋กœ ์น˜๋ฐ€ํ•œ ์กฐ์ง์„ ํ˜•์„ฑํ•˜์˜€๊ธฐ ๋•Œ๋ฌธ์ด๋‹ค.11,12) UPV์˜ ๊ฒฐ๊ณผ์—์„œ ๋‚˜ํƒ€๋‚œ ๊ฒฝํ–ฅ์„ฑ์€ ์••์ถ•๊ฐ•๋„์˜ ๊ฒฝํ–ฅ์„ฑ๊ณผ ์ƒ๋‹นํžˆ ์œ ์‚ฌํ•œ๋ฐ, ์ด๋Š” ์กฐ์ง์˜ ์น˜๋ฐ€ํ™”๊ฐ€ ๊ฐ•๋„ ํ–ฅ์ƒ์— ์ผ์ •๋ถ€๋ถ„ ์˜ํ–ฅ์„ ์ฃผ๋Š” ๊ฒƒ์œผ๋กœ ์ƒ๊ฐํ•  ์ˆ˜ ์žˆ๋‹ค.

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Fig. 3 Result of ultrasonic pulse velocity

Fig. 3์— ๋‚˜ํƒ€๋‚œ ๋ฐ”์™€ ๊ฐ™์ด Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ UPV์˜ ์ฆ๊ฐ€์œจ์„ ๋น„๊ตํ•ด๋ณด๋ฉด 2M KOH๊ฐ€ 4M KOH ๋ณด๋‹ค ์ข€ ๋” ๊ฐ€ํŒŒ๋ฅธ UPV ๋ณ€ํ™”์œจ์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ๋‹ค. ์ด๋Š” Al2O3๊ฐ€ ํ˜ผํ•ฉ๋œ GGBFS์—์„œ ํ™œ์„ฑํ™”์ œ ๋†๋„์— ๋”ฐ๋ผ ๋ฐ˜์‘์ƒ์„ฑ๋ฌผ์งˆ์˜ ์ƒ์„ฑ์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์ด ๋‹ค๋ฅธ ๊ฒƒ์œผ๋กœ ์ƒ๊ฐ๋œ๋‹ค. ๋”ฐ๋ผ์„œ Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ UPV๋Š” ์ฆ๊ฐ€ํ•˜๋Š”๋ฐ, UPV ์ฆ๊ฐ€์œจ์€ ํ™œ์„ฑํ™”์ œ์˜ ๋†๋„ ๋“ฑ์˜ ๋‹ค๋ฅธ ์š”์ธ๋„ ํ•จ๊ป˜ ๊ณ ๋ ค๋˜์–ด์•ผ ํ•  ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

3.4 ๊ณต๊ทน๋ฅ 

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Fig. 4 Volume of permeable pores

Fig. 4๋Š” Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์— ๋”ฐ๋ฅธ ์žฌ๋ น 28์ผ ์‹œํ—˜์ฒด์˜ ๊ณต๊ทน๋ฅ  ์‹œํ—˜๊ฒฐ๊ณผ์ด๋‹ค. ๊ณต๊ทน๋ฅ ์€ Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์ ์ฐจ ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ์—ˆ๋‹ค. ์ด๋Ÿฌํ•œ ๊ฒฝํ–ฅ์€ 2M๊ณผ 4M KOH์˜ ๋†๋„ ๋ชจ๋‘์—์„œ ๋ฐœ์ƒํ•˜๊ณ  ์žˆ์—ˆ๋‹ค. ์ด๋Ÿฌํ•œ ๊ณต๊ทน๋ฅ ์˜ ๊ฐ์†Œ๋Š” Al2O3๊ฐ€ ์ˆ˜ํ™”๋ฐ˜์‘์— ์˜ํ–ฅ์„ ์ฃผ์–ด ๋ฐ˜์‘ ์ƒ์„ฑ๋ฌผ์งˆ์˜ ์ƒ์„ฑ์„ ์ด‰์ง„ํ•˜๊ณ , ์ƒ์„ฑ๋œ ๋ฐ˜์‘ ์ƒ์„ฑ๋ฌผ์งˆ๋“ค์ด ์กฐ์ง์˜ ์น˜๋ฐ€ํ™”์™€ ๊ณต๊ทน ๊ฐ์†Œ์˜ ํšจ๊ณผ๋ฅผ ์œ ๋ฐœํ•˜๊ธฐ ๋•Œ๋ฌธ์œผ๋กœ ์ƒ๊ฐ๋œ๋‹ค. ์ด๋Ÿฌํ•œ ๊ณต๊ทน๋ฅ ์˜ ๊ฐ์†Œ ๊ฒฝํ–ฅ๊ณผ Fig. 1์˜ ์••์ถ•๊ฐ•๋„ ์ฆ๊ฐ€ ๊ฒฝํ–ฅ์„ฑ์„ ๋น„๊ตํ•ด ๋ณผ ๋•Œ ๊ณต๊ทน๋ฅ ์˜ ๊ฐ์†Œ๊ฐ€ ์••์ถ•๊ฐ•๋„์˜ ์ฆ๊ฐ€์— ์ผ์ •๋ถ€๋ถ„ ๊ธ์ •์ ์ธ ์˜ํ–ฅ์„ ๋ฏธ์นœ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ 4M KOH ์‹œํ—˜์ฒด์˜ ์ด ๊ณต๊ทน๋ฅ ์ด 2M KOH ์‹œํ—˜์ฒด๋“ค ๋ณด๋‹ค ๋†’๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋Š”๋ฐ, ์ด๋Š” ์ƒ๋Œ€์ ์œผ๋กœ ๋†’์€ ํ™œ์„ฑํ™”๋†๋„์— ์˜ํ•ด ๊ธ‰๊ฒฉํ•œ ์ดˆ๊ธฐ ์ˆ˜ํ™”๋ฐ˜์‘๊ณผ ์ด์— ๋”ฐ๋ฅธ ํŽ˜์ด์ŠคํŠธ์˜ ์ ์„ฑ ์ฆ๊ฐ€๋กœ ์ธํ•ด ๊ฐ‡ํžŒ๊ณต๊ธฐ(entrapped air)๊ฐ€ ์ฆ๊ฐ€ํ–ˆ๊ธฐ ๋•Œ๋ฌธ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ์ด๋Ÿฌํ•œ ์ด ๊ณต๊ทน๋Ÿ‰์˜ ์ฆ๊ฐ€์—๋„ 4M ์‹œํ—˜์ฒด์˜ ๊ฐ•๋„๊ฐ€ 2M ์‹œํ—˜๋ณด๋‹ค ๋†’๊ฒŒ ๋‚˜ํƒ€๋‚œ ๊ฒƒ์€ ์ด๊ณต๊ทน๋ฅ  ์ด์™ธ์— Al2O3์˜ ํ˜ผํ•ฉ์— ๋”ฐ๋ฅธ ๋ฐ˜์‘์ƒ์„ฑ๋ฌผ์งˆ์˜ ๋ณ€ํ™˜์ด ๊ฐ•๋„ ์ฆ๊ฐ€์— ์˜ํ–ฅ์„ ๋ฏธ์น˜๋Š” ๊ฒƒ์œผ๋กœ ์ƒ๊ฐ๋œ๋‹ค. ๊ธฐ์กด์˜ AASC์— ๊ด€ํ•œ ์—ฐ๊ตฌ์—์„œ GGBFS์˜ Al ์ด์˜จ์€ ๋ฐ˜์‘์ƒ์„ฑ๋ฌผ์งˆ์ธ C-S-H์˜ Si-O-Si ๊ฒฐํ•ฉ ์ค‘ Si๋ฅผ ๋Œ€์ฒดํ•ด Al-O-Si ๊ฒฐํ•ฉ์˜ C-A-S-H๋กœ ๋ณ€ํ•œ๋‹ค๊ณ  ํ•˜์˜€๋‹ค.21-23) ๋ณธ ์—ฐ๊ตฌ์—์„œ๋„ ํ˜ผํ•ฉํ•œ Al2O3์— ์˜ํ•ด ์ˆ˜์šฉ์•ก์ƒ์— ํ’๋ถ€ํ•œ Al์ด์˜จ์ด C-S-H์˜ ์ผ๋ถ€๋ฅผ C-A-S-H๋กœ ๋ณ€ํ™”์‹œํ‚ค๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

A. Gruskovnjak9) ๋“ฑ์€ Al2O3์˜ ํ•จ๋Ÿ‰์ด ๋†’์€ supersulphated cement (SSC)๊ฐ€ ์ƒ๋Œ€์ ์œผ๋กœ ๋‚ฎ์€ Al2O3 ํ•จ๋Ÿ‰์„ ๊ฐ€์ง€๋Š” SSC ๋ณด๋‹ค ๋†’์€ ๊ณต๊ทน๋ฅ ์„ ๊ฐ€์ง€๊ณ  ์žˆ๋‹ค๊ณ  ํ•˜์˜€๋‹ค. ์ด๋Ÿฌํ•œ ๊ฒฐ๊ณผ๋Š” ๋ณธ ์—ฐ๊ตฌ๊ฒฐ๊ณผ์™€๋Š” ๋‹ค์†Œ ์ƒ๋ฐ˜๋œ ๊ฒฝํ–ฅ์„ฑ์„ ๋ณด์ธ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ K.L. Lin12) ๋“ฑ์€ Al2O3์˜ ํ•จ์œ ๋Ÿ‰์ด ๋†’์€ slag paste์˜ ์ด ๊ณต๊ทน๋ฅ (total pore)์ด ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์˜ ๊ฒฐ๊ณผ๋ฅผ ์–ธ๊ธ‰ํ•˜์˜€๋‹ค. ๊ณต๊ทน๋ฅ ์— ๋Œ€ํ•œ ์ด๋Ÿฌํ•œ ์ฐจ์ด๋Š” ๊ณต๊ทน๋ฅ ์„ ์ธก์ •ํ•˜๋Š” ๋ฐฉ๋ฒ•๊ณผ GGBFS ์ž์ฒด๊ฐ€ ํ•จ์œ ํ•œ Al2O3์™€ ํ•จ๊ป˜ ์™ธ๋ถ€์—์„œ ์ถ”๊ฐ€๋กœ ๊ณต๊ธ‰๋œ Al2O3์˜ ์˜ํ–ฅ, OPC๊ฐ€ ์ „ํ˜€ ์—†๋Š” 100% GGBFS๋งŒ์œผ๋กœ ์ด๋ฃจ์–ด์ง„ ๊ฒฐํ•ฉ์žฌ, ํ™œ์„ฑํ™”์žฌ์˜ ์ข…๋ฅ˜์™€ ๋†๋„ ๋“ฑ์˜ ๋ณตํ•ฉ์ ์ธ ์˜ํ–ฅ์„ ๊ณ ๋ คํ•˜์—ฌ์•ผ ํ•  ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

3.5 ๊ธธ์ด๋ณ€ํ™”

/Resources/kci/JKCI.2016.28.2.205/images/Figure_CONCRETE_28_2_09_F5.jpg

Fig. 5 Drying shrinkage on the different contents of Al2O3

Fig. 5๋Š” ๊ฐ ์‹œํ—˜์ฒด์˜ ๊ธธ์ด๋ณ€ํ™”๋ฅผ ์ธก์ •ํ•œ ๊ฒฐ๊ณผ๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค. ๊ธธ์ด๋ณ€ํ™” ์ธก์ •๊ฒฐ๊ณผ Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ๊ฑด์กฐ์ˆ˜์ถ•์ด ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ์—ˆ๋‹ค. ์„ ํ–‰์—ฐ๊ตฌ ๊ฒฐ๊ณผ๋“ค ์ค‘์—์„œ Al2O3์˜ ์˜ํ–ฅ์— ๋”ฐ๋ฅธ AASC์˜ ๊ฑด์กฐ์ˆ˜์ถ•์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๋Š” ์ƒ๋Œ€์ ์œผ๋กœ ๋ถ€์กฑํ•œ ๋ถ€๋ถ„์ด๋‹ค. AASC์˜ ๊ฑด์กฐ์ˆ˜์ถ•์„ ๋ฐœ์ƒ์‹œํ‚ค๋Š” ์›์ธ์€ ๋‹ค์–‘ํ•œ ๊ฒƒ์œผ๋กœ ์•Œ๋ ค์ ธ ์žˆ๋‹ค. ํŠนํžˆ ์‹œํ—˜์ฒด ๋‚ด๋ถ€์˜ ๊ณต๊ทน์˜ ํฌ๊ธฐ์™€ ๋ถ„ํฌ๊ฐ€ ๊ฑด์กฐ์ˆ˜์ถ•์˜ ์ค‘์š” ์›์ธ๋“ค ์ค‘ ํ•˜๋‚˜๋กœ ์ฃผ๋ชฉ๋ฐ›๊ณ  ์žˆ๋‹ค.16-18)

Fig. 4์— ๋‚˜ํƒ€๋‚œ ๋ฐ”์™€ ๊ฐ™์ด Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์‹œํ—˜์ฒด ๋‚ด๋ถ€์˜ ์ „์ฒด ๊ณต๊ทน๋ฅ ์ด ๊ฐ์†Œํ•˜๊ณ  ์žˆ๊ณ , ์ด์— ๋”ฐ๋ผ ๊ฑด์กฐ์ˆ˜์ถ•์˜ ๊ฐ์†Œ๋„ ์œ ์‚ฌํ•œ ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ์—ˆ๋‹ค. ๋”ฐ๋ผ์„œ Al2O3์˜ ํ˜ผํ•ฉ๋ฅ  ์ฆ๊ฐ€๊ฐ€ ์ด๊ณต๊ทน๋Ÿ‰์„ ๊ฐ์†Œ์‹œํ‚ค๊ณ  ๋ฐ˜์‘ ์ƒ์„ฑ๋ฌผ์งˆ๋“ค์— ์˜ํ•ด ์กฐ์ง ๊ตฌ์กฐ๋ฅผ ์น˜๋ฐ€ํ•˜๊ฒŒ ๋งŒ๋“ค์–ด ์‹œํ—˜์ฒด์˜ ์ „์ฒด์ ์ธ ๊ณต๊ทน์„ ๊ฐ์†Œ์‹œ์ผœ ๊ฑด์กฐ์ˆ˜์ถ•์„ ์ €๊ฐ์‹œํ‚ค๋Š” ํšจ๊ณผ๋ฅผ ๋‚˜ํƒ€๋‚ด๋Š” ๊ฒƒ์œผ๋กœ ์ƒ๊ฐ๋œ๋‹ค. ํ˜ผํ•ฉ๋œ Al2O3์ค‘ ์ผ๋ถ€๋Š” ettringite, C-S-H ๋“ฑ๊ณผ ๊ฐ™์€ ๋ฐ˜์‘์ƒ์„ฑ๋ฌผ์งˆ์˜ ์ƒ์„ฑ์— ๊ด€์—ฌํ•˜๋Š”๋ฐ, ettringite ๋“ฑ์€ ๋ถ€ํ”ผํŒฝ์ฐฝ์„ ์œ ๋ฐœํ•œ๋‹ค.19-23) ๋˜ํ•œ ๋ฐ˜์‘์ƒ์„ฑ๋ฌผ์งˆ์˜ ์ƒ์„ฑ์ด ์ด‰์ง„๋จ์— ๋”ฐ๋ผ ์ผ๋ถ€ ๊ณต๊ทน์˜ ์ถฉ์ง„ํšจ๊ณผ๋กœ ์ธํ•˜์—ฌ ๊ฑด์กฐ์ˆ˜์ถ• ๊ฐ์†Œ์— ์˜ํ–ฅ์„ ๋ฏธ์นœ ๊ฒƒ์œผ๋กœ ์ƒ๊ฐ๋œ๋‹ค. ๋”ฐ๋ผ์„œ ๋ณธ ์—ฐ๊ตฌ์˜ ๋ฒ”์œ„์—์„œ ์‚ดํŽด๋ณผ ๋•Œ, Al2O3์˜ ํ˜ผํ•ฉ์€ ๊ฑด์กฐ์ˆ˜์ถ• ๊ฐ์†Œ์— ์ผ์ • ๋ถ€๋ถ„ ๊ธ์ •์ ์ธ ํšจ๊ณผ๋ฅผ ์ผ์œผํ‚ค๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ์ด๋Ÿฌํ•œ ๊ฑด์กฐ์ˆ˜์ถ• ๊ฐ์†Œํšจ๊ณผ๋Š” Fig. 4์˜ ๊ณต๊ทน๋ฅ  ์‹œํ—˜๊ฒฐ๊ณผ์™€ ํ•จ๊ป˜ ์—ฐ๊ด€ ์ง€์„ ์ˆ˜ ์žˆ๋Š”๋ฐ, ์„ ํ–‰ ์—ฐ๊ตฌ์ž๋“ค์˜ ์—ฐ๊ตฌ๊ฒฐ๊ณผ์—์„œ AASC์˜ ๊ฑด์กฐ์ˆ˜์ถ•์— ์˜ํ–ฅ์„ ์ฃผ๋Š” ์ค‘์š” ์š”์ธ ์ค‘์— ๊ณต๊ทน๋ฅ ์„ ์–ธ๊ธ‰ํ•˜๊ณ  ์žˆ๋‹ค.16-18) ๋”ฐ๋ผ์„œ Fig. 4์— ๋‚˜ํƒ€๋‚œ ๋ฐ”์™€ ๊ฐ™์ด Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ๊ณต๊ทน๋ฅ ์ด ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์„ฑ์€ ๊ฑด์กฐ์ˆ˜์ถ•์˜ ๊ฐ์†Œ์—๋„ ์˜ํ–ฅ์„ ์ฃผ๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

์•„์ง๊นŒ์ง€ AASC์˜ ๊ฑด์กฐ์ˆ˜์ถ•์— ์˜ํ–ฅ์„ ๋ฏธ์น˜๋Š” ๋ช…ํ™•ํ•œ ์›์ธ์ด ๋ฐํ˜€์ง„ ๊ฒƒ์€ ์•„๋‹ˆ์ง€๋งŒ, ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์ด ๊ณต๊ทน๋ฅ ๊ณผ UPV ์ธก์ • ๊ฒฐ๊ณผ๋ฅผ ๋ฐ”ํƒ•์œผ๋กœ ๊ฑด์กฐ์ˆ˜์ถ•์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์„ ํ•จ๊ป˜ ๊ณ ๋ คํ•ด ๋ณผ ๋•Œ Al2O3์˜ ํ˜ผํ•ฉ์€ ์ผ์ •์ˆ˜์ค€์˜ ๋ฒ”์œ„์—์„œ ๊ฑด์กฐ์ˆ˜์ถ• ๊ฐ์†Œ์— ์˜ํ–ฅ์„ ๋ฏธ์น˜๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

Table 4๋Š” ์žฌ๋ น 91์—์„œ ์ธก์ •ํ•œ ๊ฐ ์‹œํ—˜์ฒด์˜ ์ตœ์ข… ๊ฑด์กฐ์ˆ˜์ถ•์œจ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค. 2M KOH์˜ ๊ฒฝ์šฐ 16% Al2O3 ํ˜ผํ•ฉ๋ฅ ์—์„œ Al2O3๋ฅผ ํ˜ผํ•ฉํ•˜์ง€ ์•Š์€ ๊ฒฝ์šฐ๊ณผ ๋น„๊ตํ•˜์—ฌ ์•ฝ 12.4%, 4M KOH์˜ 16% Al2O3 ํ˜ผํ•ฉ๋ฅ ์ผ๋•Œ๋Š” ์•ฝ 12.2%์˜ ๊ฑด์กฐ์ˆ˜์ถ•์œจ ๊ฐ์†Œ๊ฐ€ ๋ฐœ์ƒํ•˜์˜€๋‹ค. 4M KOH์™€ 2M KOH์˜ ๊ฒฝ์šฐ ๋ชจ๋‘ Al2O3์˜ ํ˜ผํ•ฉ์— ์˜ํ•ด ๋‚ฎ์€ ๊ฑด์กฐ์ˆ˜์ถ•์œจ์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค. ์ด๋Š” ํ˜ผํ•ฉ๋œ Al2O3๊ฐ€ ettringite ๋“ฑ๊ณผ ๊ฐ™์€ ๋ฐ˜์‘ ์ƒ์„ฑ๋ฌผ์งˆ๋“ค์— ์˜ํ•œ ์กฐ์ง์˜ ์น˜๋ฐ€ํ™”, ๊ณต๊ทน ์ถฉ์ง„ํšจ๊ณผ ๋“ฑ์˜ ๋ณตํ•ฉ์  ์ž‘์šฉ์— ์˜ํ•ด ๊ฑด์กฐ์ˆ˜์ถ•์œจ ๊ฐ์†Œ๊ฐ€ ๋‚˜ํƒ€๋‚œ ๊ฒƒ์œผ๋กœ ์ƒ๊ฐ๋œ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ 2M๊ณผ 4M KOH ๋†๋„์˜ ๋ชจ๋“  ์‹œํ—˜์ฒด์—์„œ 16% Al2O3์—์„œ์˜ ๊ฑด์กฐ์ˆ˜์ถ•์œจ๊ณผ 0% Al2O3์˜ ๊ฑด์กฐ์ˆ˜์ถ•์œจ๊ณผ์˜ ์ฐจ์ด๋Š” ๊ฐ๊ฐ 0.0237%์™€ 0.0336%๋ฅผ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

Table 4 Ultimate length change ratio at 91 days

Length change (%)

Al2O3

content(%)

2M KOH

4M KOH

0

-0.1914

-0.2758

2

-0.1844

-0.2645

4

-0.1773

-0.2638

6

-0.1764

-0.2564

8

-0.1742

-0.2597

10

-0.1755

-0.2531

12

-0.1696

-0.2532

14

-0.1692

-0.2483

16

-0.1677

-0.2422

3.6 SEM

Fig. 6์€ SEM ๊ด€์ฐฐ ์ด๋ฏธ์ง€๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค. SEM์€ ๊ฐ KOH์˜ ๋†๋„์— ๋Œ€ํ•ด Al2O3๋ฅผ ํ˜ผํ•ฉํ•˜์ง€ ์•Š์€ ๋น„๊ต๊ตฐ๊ณผ ์ตœ๊ณ ๊ฐ•๋„๋ฅผ ๋ฐœ์ƒ์‹œํ‚จ 16% Al2O3 ํ˜ผํ•ฉ๋ฅ ์˜ ์‹œํ—˜์ฒด์— ๋Œ€ํ•ด ์ธก์ •ํ•˜์˜€๋‹ค. SEM ๋ถ„์„๊ฒฐ๊ณผ 16% Al2O3 ํ˜ผํ•ฉํ•œ ์‹œํ—˜์ฒด(Fig. 6(b) and 6(d))์˜ ์กฐ์ง์ด Al2O3๋ฅผ ํ˜ผํ•ฉํ•˜์ง€ ์•Š์€ ์‹œํ—˜์ฒด(Fig. 6(a) and 6(c))์™€ ๋น„๊ตํ•˜์—ฌ ์น˜๋ฐ€ํ•œ ์กฐ์ง์„ ๊ด€์ฐฐ ํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค.

/Resources/kci/JKCI.2016.28.2.205/images/Figure_CONCRETE_28_2_09_F6.jpg

Fig. 6 SEM images

A. Gruskovnjak9)๋Š” Al2O3์˜ ํ•จ์œ ์œจ์ด ๋‹ค๋ฅธ sulphated slag cement์˜ ์‹œํ—˜์—์„œ Al2O3์˜ ํ•จ์œ ์œจ์ด ๋†’์€ ์‹œํ—˜์ฒด๊ฐ€ ettringite ๋“ฑ์˜ ์ƒ์„ฑ์ด ์ƒ๋Œ€์ ์œผ๋กœ ๋งŽ์•„์ ธ ์น˜๋ฐ€ํ•œ ์กฐ์ง๊ตฌ์กฐ๋ฅผ ๋งŒ๋“ ๋‹ค๊ณ  ํ•˜์˜€๋‹ค. S. Barbuhuiya11) ๋“ฑ์€ nano-Al2O3๋ฅผ ์‚ฌ์šฉํ•œ OPC paste ์‹œํ—˜์ฒด์˜ ์กฐ์ง์ด ์น˜๋ฐ€ํ•˜๊ฒŒ ๋˜๋Š” ๊ฒƒ์„ SEM ๊ด€์ฐฐ์„ ํ†ตํ•ด ํ™•์ธํ•˜์˜€๋‹ค.

Table 5๋Š” Al2O3๋ฅผ ํ˜ผํ•ฉํ•˜์ง€ ์•Š์€ ๋น„๊ต๊ตฐ๊ณผ ์ตœ๊ณ ๊ฐ•๋„๋ฅผ ๋‚˜ํƒ€๋‚ธ 2M KOH, 2M KOH + 16% Al2O3, 4M KOH, 4M KOH + 16% Al2O3์˜ 4๊ฐ€์ง€ ์‹œํ—˜์ฒด์— ๋Œ€ํ•ด EDX ๋ถ„์„์„ ์ˆ˜ํ–‰ํ•˜์—ฌ ๋ฐ˜์‘์ƒ์„ฑ๋ฌผ์งˆ๋“ค์˜ ๊ตฌ์„ฑ์„ฑ๋ถ„๋น„๋ฅผ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ํ‘œ๋ณธ์€ Fig. 6์˜ (a)~(d) ๊ด€์ฐฐ๋ถ€๋ถ„์— ๋Œ€ํ•ด ๊ฐ๊ฐ 25๊ฐœ์˜ ์ž„์˜ ์ง€์ ์„ ์„ ํƒํ•˜์—ฌ ๋ถ„์„ํ•˜์˜€๋‹ค.

Table 5 Atomic ratios in the hydrate phases obtained by EDX analysis

Specimens

Ca/Si

Al/Si

Al/Ca

2M KOH

1.70

0.40

0.23

2M KOH+16% Al2O3

1.64

0.49

0.30

4M KOH

2.50

0.35

0.14

4M KOH+16% Al2O3

1.50

0.56

0.37

2M KOH์™€ 4M KOH ๋ชจ๋‘ Al2O3์˜ ํ˜ผํ•ฉ์— ๋”ฐ๋ผ Ca/Si ๋น„๋Š” ๊ฐ์†Œํ•˜๊ณ , Al/Si์™€ Al/Ca ๋น„๋Š” ์ฆ๊ฐ€ํ•œ ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค.

X. Pardal7) ๋“ฑ์˜ ์—ฐ๊ตฌ์—์„œ Al2O3๋Š” C-S-H (calcium silicate hydrate)์˜ ํ˜•์„ฑ์— ์˜ํ–ฅ์„ ์ฃผ๊ณ  ๊ทธ ๊ฒฐ๊ณผ๋กœ C-A-S-H (calcium aluminosilicate hydrate)๊ฐ€ ํ˜•์„ฑ๋˜๋Š”๋ฐ ์ด๋•Œ Al2O3์˜ ๋†๋„๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ Al/Si๋„ ์ฆ๊ฐ€ํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋ณด์˜€๋‹ค. A. Gruskovnjak et al.9)๋Š” super sulphated slag cement์—์„œ GGBFS ์ž์ฒด๊ฐ€ ํ•จ์œ ํ•œ Al2O3์˜ ์–‘์ด ์ ์„์ˆ˜๋ก ettringite์˜ ์ƒ์„ฑ์ด ์ ๋‹ค๊ณ  ํ•˜์˜€๋‹ค. Al์˜ ์˜ํ–ฅ์€ ์ฃผ๋กœ C-S-H์˜ ๊ตฌ์กฐ์˜ ํ˜•์„ฑ์— ์˜ํ–ฅ์„ ๋ฏธ์ณ C-A-S-H๋ฅผ ํ˜•์„ฑํ•˜๋Š”๋ฐ ์ฃผ๋กœ Al์˜ ์ž‘์šฉ์„ ์–ธ๊ธ‰ํ•œ ์ด์ „ ์—ฐ๊ตฌ๊ฐ€ ๋ช‡๋ช‡ ์žˆ์—ˆ๋‹ค.6-9,21-23) 2M KOH์™€ 2M KOH + 16% Al2O3 ๊ทธ๋ฆฌ๊ณ  4M KOH์™€ 4M KOH + 16% Al2O3์˜ Al/Si๋ฅผ ๋ณด๋ฉด Al2O3๋ฅผ ํ˜ผํ•ฉ๋ฅ ์ด ๋†’์•„์ง์— ๋”ฐ๋ผ Al/Si๊ฐ€ ๋†’์•„์ง€๋Š” ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์ด๋Š” R. Tanzer et al.14)์˜ ์—ฐ๊ตฌ๊ฒฐ๊ณผ์—์„œ ์–ธ๊ธ‰ํ•œ ๊ฒƒ์ฒ˜๋Ÿผ, NaOH๋กœ ํ™œ์„ฑํ™”๋œ AASC์—์„œ Al2O3์˜ ํ•จ์œ ๋Ÿ‰์ด ์ ์€ GGBFS์˜ Si/Al์ด ๋‚ฎ๊ฒŒ ๋‚˜ํƒ€๋‚œ ๊ฒฐ๊ณผ์™€ KOH๋ฅผ GGBFS์˜ ํ™œ์„ฑํ™”์ œ๋กœ ์‚ฌ์šฉํ•œ ๋ณธ ์—ฐ๊ตฌ์˜ ๊ฒฐ๊ณผ๋„ ์œ ์‚ฌํ•œ ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด๊ณ  ์žˆ์—ˆ๋‹ค. Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด 0์—์„œ 16%๋กœ ๋†’์•„์กŒ์„ ๋•Œ Ca/Si์™€ Al/Si์˜ ๊ตฌ์„ฑ๋น„์œจ ๋ณ€ํ™”๊ฒฝํ–ฅ์„ฑ์€ M.B. Haha15)๊ฐ€ ์–ธ๊ธ‰ํ•œ ๊ฒฝํ–ฅ์„ฑ๊ณผ๋„ ์œ ์‚ฌํ•˜๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๋”ฐ๋ผ์„œ AASC์—์„œ GGBFS ์ž์ฒด๊ฐ€ ํ•จ์œ ํ•œ Al2O3์˜ ์˜ํ–ฅ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ์™ธ๋ถ€์—์„œ ์ถ”๊ฐ€๋กœ ๊ณต๊ธ‰๋˜๋Š” Al2O3์— ์˜ํ•œ ์˜ํ–ฅ๋„ ์œ ์‚ฌํ•œ ๊ฒฝํ–ฅ์„ฑ์„ ๋‚˜ํƒ€๋‚ด๋Š” ๊ฒƒ์œผ๋กœ ์ƒ๊ฐํ•  ์ˆ˜ ์žˆ๋‹ค.

๊ทธ๋Ÿฌ๋‚˜ ์ผ๋ถ€ ์‹œํ—˜์ฒด์—์„œ๋Š” Fig. 7์—์„œ์™€ ๊ฐ™์ด ๊ณ ๋ฅด๊ฒŒ ๋ถ„์‚ฐ๋˜์ง€ ๋ชปํ•œ Al2O3 ์ž…์ž๋“ค์ด ๋ฐœ๊ฒฌ๋˜๊ธฐ๋„ ํ•˜์˜€๋‹ค. ๋”ฐ๋ผ์„œ AASC์—์„œ ํšจ๊ณผ์ ์ธ Al2O3์˜ ๋ถ„์‚ฐ๊ณผ ์„ฑ๋Šฅ ํ–ฅ์ƒ์„ ์œ„ํ•ด์„œ๋Š” ์ถฉ๋ถ„ํ•œ ๋น„๋น”์‹œ๊ฐ„๊ณผ ์ ์ ˆํ•œ ํ˜ผํ™”์ œ์˜ ์„ ์ • ๋“ฑ์ด ํ•„์š”ํ•  ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

/Resources/kci/JKCI.2016.28.2.205/images/Figure_CONCRETE_28_2_09_F7.jpg

Fig. 7 4M KOH + 16% Al2O3

4. ๊ฒฐ    ๋ก 

KOH๋กœ ํ™œ์„ฑํ™”๋œ ์•Œ์นผ๋ฆฌ ํ™œ์„ฑํ™” ์Šฌ๋ž˜๊ทธ ์‹œ๋ฉ˜ํŠธ(AASC)์˜ Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์— ๋”ฐ๋ฅธ ํŠน์„ฑ์— ๊ด€ํ•œ ์—ฐ๊ตฌ๊ฒฐ๊ณผ ๋ณธ ์—ฐ๊ตฌ์˜ ๋ฒ”์œ„ ๋‚ด์—์„œ ๋‹ค์Œ๊ณผ ๊ฐ™์€ ๊ฒฐ๋ก ์„ ์–ป์—ˆ๋‹ค.

1)ํ™œ์„ฑํ™”์ œ์˜ ๋†๋„์— ๊ด€๊ณ„์—†์ด Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ• ์ˆ˜๋ก ์ดˆ๊ธฐ(1, 3์ผ) ๋ฐ ์žฅ๊ธฐ๊ฐ•๋„(28์ผ) ๋ชจ๋‘ ์ฆ๊ฐ€ํ•˜์˜€๋‹ค. ์ด๋Š” Al2O3์˜ ํ˜ผํ•ฉ์— ์˜ํ•ด ๋ฐ˜์‘์ƒ์„ฑ๋ฌผ์งˆ ์ƒ์„ฑ์ด ์ด‰์ง„๋˜๊ณ , ์‹œํ—˜์ฒด์˜ ๋ฏธ์„ธ๊ตฌ์กฐ๋ฅผ ์น˜๋ฐ€ํ•˜๊ฒŒ ๋งŒ๋“ค์–ด ๊ฐ•๋„ํ–ฅ์ƒ์— ๊ธ์ •์ ์ธ ํšจ๊ณผ๋ฅผ ์ฃผ๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

2)Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์ดˆ์ŒํŒŒ ์†๋„๋Š” ์ฆ๊ฐ€ํ•˜์˜€๋‹ค. ๋˜ํ•œ ์ด๊ณต๊ทน๋ฅ ์€ Al2O3์˜ ํ˜ผํ•ฉ๋ฅ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์ด๋Š” Al2O3๊ฐ€ C-A-S-H์™€ ettringite ๋“ฑ์˜ ๋ฐ˜์‘ ์ƒ์„ฑ๋ฌผ ์ƒ์„ฑ์„ ์ด‰์ง„ํ•˜์—ฌ ์‹œํ—˜์ฒด์˜ ๋ฏธ์„ธ์กฐ์ง์„ ์น˜๋ฐ€ํ•˜๊ฒŒ ๋งŒ๋“ค๊ณ  ์ผ๋ถ€ ๊ณต๊ทน์ถฉ์ง„ํšจ๊ณผ์˜ ๋ฐœ์ƒ ๋•Œ๋ฌธ์œผ๋กœ ์ƒ๊ฐ๋œ๋‹ค.

3)SEM๊ณผ EDS ๋ถ„์„๊ฒฐ๊ณผ Al2O3์˜ ํ˜ผํ•ฉ์— ์˜ํ•ด ์น˜๋ฐ€ํ•ด์ง„ ์กฐ์ง์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค. ๋˜ํ•œ KOH์˜ ๋†๋„์— ๊ด€๊ณ„์—†์ด Al2O3์˜ ํ˜ผํ•ฉ์— ์˜ํ•ด Ca/Si ๋น„๋Š” ๊ฐ์†Œํ•˜๊ณ , Al/Si์™€ Al/Ca ๋น„๋Š” ์ฆ๊ฐ€ํ•˜์˜€๋‹ค.

4)๊ธฐ์กด์˜ OPC์™€ AASC์˜ ์—ฐ๊ตฌ์—์„œ GGBFS์— ํ•จ์œ ํ•œ Al2O3์˜ ํšจ๊ณผ์™€ ๋น„๊ตํ•˜์—ฌ ๋ณธ ์—ฐ๊ตฌ์—์„œ ์ ์šฉํ•œ Al2O3๋ฅผ ์™ธ๋ถ€ ํ˜ผํ•ฉํ•œ ๋ฐฉ์‹์˜ AASC์—์„œ๋Š” ๊ฐ•๋„ํ–ฅ์ƒ๊ณผ ๋ฏธ์„ธ์กฐ์ง์˜ ์น˜๋ฐ€ํ™” ๋“ฑ์˜ ๊ธ์ •์ ์ธ ํšจ๊ณผ๋ฅผ ๋‚˜ํƒ€๋‚ผ ์ˆ˜ ์žˆ๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

AASC์—์„œ Al2O3์˜ ํ˜ผํ•ฉ์— ๋”ฐ๋ฅธ ํŠน์„ฑ ํŒŒ์•…์„ ์œ„ํ•ด ๊ธฐ์กด ์—ฐ๊ตฌ๋“ค๊ณผ ํ•จ๊ป˜ ๋ฏธ์„ธ๊ตฌ์กฐ์™€ ๋ฐ˜์‘๋ฉ”์ปค๋‹ˆ์ฆ˜์˜ ํŒŒ์•…์„ ์œ„ํ•œ ํ›„์† ์—ฐ๊ตฌ๊ฐ€ ์ด์–ด์ ธ์•ผ ํ•  ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

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