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Journal of the Korea Concrete Institute

J Korea Inst. Struct. Maint. Insp.
  • Indexed by
  • Korea Citation Index (KCI)

  1. ์ •ํšŒ์›,๋Œ€์ „๋Œ€ํ•™๊ต ํ† ๋ชฉ๊ณตํ•™๊ณผ ์กฐ๊ต์ˆ˜
  2. ์ •ํšŒ์›,๋™์‚ฐ์ฝ˜ํฌ๋ฆฌํŠธ์‚ฐ์—…(์ฃผ)๊ธฐ์—…๋ถ€์„ค์—ฐ๊ตฌ์†Œ ์ฑ…์ž„์—ฐ๊ตฌ์›
  3. ์ •ํšŒ์›,์ถฉ๋‚จ๋Œ€ํ•™๊ต ํ† ๋ชฉ๊ณตํ•™๊ณผ ๊ต์ˆ˜, ๊ต์‹ ์ €์ž



์ธ๊ณต์–ด์ดˆ, 3D ํ”„๋ฆฐํŒ…, ์ €์•Œ์นผ๋ฆฌ, ์•ŒํŒŒํ˜•๋ฐ˜์ˆ˜์„๊ณ 
Artificial reef, 3D Printing, Low alkali, Alpha-hemihydrate gypsum

1. ์„œ ๋ก 

์šฐ๋ฆฌ๋‚˜๋ผ๋Š” 1971๋…„๋ถ€ํ„ฐ ์ˆ˜์‚ฐ์ž์› ์ฆ๋Œ€ ๋ฐ ์–ด์กฑ์ž์› ๋ณดํ˜ธ๋ฅผ ๋ชฉ์ ์œผ๋กœ ์ธ๊ณต์–ด์ดˆ ์‚ฌ์—…์„ ์‹ค์‹œํ•˜์˜€์œผ๋ฉฐ, 2010๋…„ ์ดํ›„ ์—ฐ๊ฐ„ 3~4๋ฐฑ์–ต์˜ ์ง€์›์ด ์ด๋ฃจ์–ด์ ธ 1~2๋งŒ๊ฐœ/year ์˜ ์ธ๊ณต์–ด์ดˆ๊ฐ€ ์„ค์น˜๋˜๊ณ  ์žˆ๋‹ค.

ํ˜„์žฌ ๊ตญ๋‚ด ํ•ด์ค‘๋ฆผ ๋ฐ ์ธ๊ณต์–ด์ดˆ ๊ด€๋ จ ํŠนํ—ˆ๋Š” ์•ฝ 1,000๊ฑด ์ด์ƒ์œผ๋กœ ์ตœ๊ทผ ์—ฐ๊ฐ„ 100๊ฑด ์ด์ƒ์˜ ํŠนํ—ˆ๊ฐ€ ๋“ฑ๋ก๋˜๊ณ  ์žˆ๋Š” ์ถ”์„ธ๋กœ ๊ด€๋ จ ์—ฐ๊ตฌ๊ฐ€ ํ™œ๋ฐœํžˆ ์ง„ํ–‰๋˜๊ณ  ์žˆ์œผ๋‚˜, ์—ฌ์ „ํžˆ ๋ฐ”๋‹ค์˜ ๊ฐฏ๋…น์Œํ˜„์ƒ ๋“ฑ์ด ๋ฐœ์ƒํ•  ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ์—ฐ์•ˆํ•ด์—ญ์˜ ์–ดํš๋Ÿ‰๋„ ๊พธ์ค€ํ•œ ๊ฐ์†Œ ์ถ”์„ธ์— ์žˆ๋Š” ์‹ค์ •์ด๋‹ค.

๋”ฐ๋ผ์„œ ์ด๋Ÿฌํ•œ ๋ฌธ์ œ์ ์„ ํ•ด๊ฒฐํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ํ•ด์™ธ์—์„œ๋Š” ํ•ด์–‘์ƒ๋ฌผ์˜ ์„œ์‹ํ™˜๊ฒฝ์— ๋ณด๋‹ค ์ ํ•ฉํ•œ ํ™˜๊ฒฝ์„ ์ œ๊ณตํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์ธ๊ณต์–ด์ดˆ๋ฅผ ํ†ตํ•œ ํ•ด์–‘๋ชฉ์žฅ ์กฐ์„ฑ์‚ฌ์—…์„ ์ถ”์ง„ํ•˜๊ณ  ์žˆ๋‹ค. ์ธ๊ณต์–ด์ดˆ๋Š” ์ œ์ž‘ ๋‹จ๊ฐ€ ๋ฐ ํŽธ์˜์„ฑ์„ ๊ณ ๋ คํ•˜์—ฌ ๋Œ€ํ˜•์ธ ๊ฒฝ์šฐ๋Š” ๊ฐ•์žฌ๋กœ ์ œ์ž‘๋˜๊ณ , ์ค‘์†Œํ˜•์˜ ์ธ๊ณต์–ด์ดˆ๋Š” ๋Œ€๋ถ€๋ถ„ ์ฒ ๊ทผ์ฝ˜ํฌ๋ฆฌํŠธ๋กœ ์ œ์ž‘๋˜๋Š”๋ฐ, ์ด๋Ÿฌํ•œ ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ํŠน์ง• ์ค‘์— ํ•˜๋‚˜์ธ ๊ฐ•์•Œ์นผ๋ฆฌ์„ฑ์œผ๋กœ ์ธํ•ด ์ฒ ๊ทผ์˜ ๋ถ€์‹์„ ๋ฐฉ์ง€ํ•˜๊ณ  ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ๋†’์€ ๊ฐ•๋„๋ฅผ ๋ฐœํ˜„ํ•˜๋Š” ์žฅ์ ์ด ์žˆ์œผ๋‚˜, ํ•ด์ค‘์— ์นจ์ง€๋˜๋ฉด ํ•ด์ˆ˜์˜ ํ‰๊ท  pH 8~9 ๋ณด๋‹ค ๋†’์€ pH 12~13์˜ ๊ฐ•์•Œ์นผ๋ฆฌ ์„ฑ๋ถ„์„ ์šฉ์ถœํ•˜์—ฌ ์ฃผ๋ณ€์˜ ๋ฏธ์ƒ๋ฌผ ๋ฐ ํ•ด์–‘์ƒ๋ฌผ์˜ ์ƒํƒœํ™˜๊ฒฝ ๋ฐ ์„ฑ์žฅ์— ์•…์˜ํ–ฅ์„ ๋ฏธ์น˜๊ฒŒ ๋œ๋‹ค(Kim et al., 2007; Park, 2007; Park, 2012). ํŠนํžˆ ์ธ๊ณต์–ด์ดˆ์˜ ์ฃผ์š”ํ•œ ๊ธฐ๋Šฅ ์ค‘์— ํ•˜๋‚˜์ธ ์œ„์ง‘ํšจ๊ณผ๋ฅผ ์ฆ๋Œ€์‹œํ‚ค๊ธฐ ์œ„ํ•ด์„œ๋Š” ํ•ด์–‘์ƒ๋ฌผ์˜ ์„œ์‹ํ™˜๊ฒฝ์— ์ ํ•ฉํ•œ ํฌ๊ธฐ์™€ ํ˜•์ƒ์ด ์ œ๊ณต๋˜์–ด์•ผ ํ• ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ํ•ด์–‘์ƒ๋ฌผ์˜ ๋จน์ด์›์„ ์ œ๊ณตํ•ด์ฃผ๊ธฐ ์œ„ํ•œ ์ €์„œ์ƒ๋ฌผ์˜ ์„œ์‹ํ™˜๊ฒฝ์ด ๋จผ์ € ์ œ๊ณต๋˜์–ด์•ผ ํ•˜๋ฏ€๋กœ, ์ด๋ฅผ ์œ„ํ•ด์„œ๋Š” ์นœํ™˜๊ฒฝ์ ์ธ ์–ด์ดˆ ์†Œ์žฌ์˜ ๊ฐœ๋ฐœ์ด ์ค‘์š”ํ•˜๊ณ  ํ•  ์ˆ˜ ์žˆ๋‹ค.

์ตœ๊ทผ 3D ํ”„๋ฆฐํ„ฐ๋ฅผ ๊ฑด์„ค ์ œํ’ˆ์— ํ™œ์šฉํ•˜๊ธฐ ์œ„ํ•˜์—ฌ 3D ํ”„๋ฆฐํ„ฐ์šฉ ๋ชจ๋ฅดํƒ€๋ฅด๋ฅผ ๊ฐœ๋ฐœํ•˜๋Š” ์—ฐ๊ตฌ๊ฐ€ ํ™œ๋ฐœํžˆ ์ด๋ฃจ์–ด์ง€๊ณ  ์žˆ๋‹ค(Seo et al., 2019).

์ผ๋ฐ˜์ ์œผ๋กœ ์ธ๊ณต์–ด์ดˆ์—๋Š” ํฌ๋Ÿฌ์Šค์ฝ˜ํฌ๋ฆฌํŠธ๋ฅผ ์ ์šฉํ•˜๋Š” ๊ฒƒ์ด ๋งŽ์€ ์žฅ์ ์ด ์žˆ์œผ๋‚˜(Kim et al., 2014;Lee et al., 2013; Lee et al., 2011), ๊ธฐ์กด์˜ ๊ณต๋ฒ•์œผ๋กœ๋Š” ์ œ์ž‘์ด ํž˜๋“  ๋‹ค์–‘ํ•œ ํ˜•์ƒ์„ ๊ตฌํ˜„ํ•˜๊ธฐ์— ์œ ๋ฆฌํ•œ 3D ํ”„๋ฆฐํ„ฐ์šฉ ๋ชจ๋ฅดํƒ€๋ฅด๋ฅผ ์ธ๊ณต์–ด์ดˆ์— ์ ์šฉํ•˜๋Š” ์—ฐ๊ตฌ๋„ ์ง„ํ–‰๋˜๊ณ  ์žˆ๋‹ค(Kim et al., 2021).

3Dํ”„๋ฆฐํ„ฐ๋ฅผ ์ด์šฉํ•œ ์ธ๊ณต์–ด์ดˆ ์ œ์ž‘์€ ํฌ๊ฒŒ ๋ชจ๋ฅดํƒ€๋ฅด์˜ ๋ฐฐํ•ฉ/๋ฏน์‹ฑ๋ถ€์™€ ์ถœ๋ ฅ๋ถ€๋กœ ๊ตฌ๋ถ„ํ•  ์ˆ˜ ์žˆ๊ณ , ์ด๋Š” ๊ธฐ์กด ๋ชจ๋ฅดํƒ€๋ฅด์˜ ์žฌ๋ฃŒ์ €์žฅ/๋ฐฐํ•ฉ/๋ฏน์‹ฑ ๊ธฐ์ˆ ๊ณผ CNC๊ฐ€๊ณต๊ธฐ์ˆ ์˜ ๊ฒฐํ•ฉ์œผ๋กœ ์„ค๋ช…ํ•  ์ˆ˜ ์žˆ๋‹ค. ์ด๋Ÿฌํ•œ ์ถœ๋ ฅ๋ฐฉ์‹์€ ์ œํ’ˆ ๋ชจ๋ธ๋ง์„ ํ†ตํ•ด ์ขŒํ‘œ๋ฅผ ์ถ”์ถœํ•˜๊ณ  ํ•ด๋‹น์ขŒํ‘œ ์ง€์ ์— ์ ์ ˆํ•œ ๋ฐฐํ•ฉ๋น„์œจ๋กœ ๋ฏน์‹ฑ๋œ ๋ชจ๋ฅดํƒ€๋ฅด๋ฅผ ์••์†กํ•˜๋Š” ์ˆœ์„œ๋กœ ์ด๋ฃจ์–ด์ง„๋‹ค.

ํ•œํŽธ, ์˜จ์‹ค๊ฐ€์Šค ์ €๊ฐ์„ ์œ„ํ•œ ์žฅ๊ธฐ ์ €ํƒ„์†Œ๋ฐœ์ „์ „๋žต(LEDS)์— ๋”ฐ๋ผ ์‹œ๋ฉ˜ํŠธ ์ œ์กฐ๋ถ„์•ผ ๋ฐ ์‚ฐ์—…๋ถ„์•ผ์—์„œ์˜ ํƒ„์†Œ์ €๊ฐ์„ ์œ„ํ•˜์—ฌ ์‹ค๋ฆฌ์นดํ“ธ, ํ”Œ๋ผ์ด์• ์‹œ ๋“ฑ์˜ ์‚ฐ์—…๋ถ€์‚ฐ๋ฌผ ๋“ฑ์˜ ํ™œ์šฉ์ด ๊ธฐ๋Œ€๋˜๊ณ  ์žˆ์œผ๋‚˜, ์ด์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๋Š” ๋‹จ์œ„์‹œ๋ฉ˜ํŠธ๋Ÿ‰ ์ €๊ฐ ๊ด€์ ์—์„œ ์ ‘๊ทผํ•  ๋ฟ ์ฃผ๋ณ€ ํ™˜๊ฒฝ์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๋Š” ์ „๋ฌดํ•œ ์‹ค์ •์ด๋‹ค.

์ด์™€ ๊ฐ™์ด ์‹œ๋ฉ˜ํŠธ์˜ ๊ฐ•์•Œ์นผ๋ฆฌ๋Š” ๋งค์šฐ ์ค‘์š”ํ•œ ํŠน์„ฑ์ด์ง€๋งŒ ํ™˜๊ฒฝ์— ๋ฏธ์น˜๋Š” ์•…์˜ํ–ฅ์—๋„ ๋ถˆ๊ตฌํ•˜๊ณ  ์ด์— ๋Œ€ํ•œ ๊ทœ์ œ๋‚˜ ๊ฐ€์ด๋“œ๋ผ์ธ์€ ์—†๋Š” ๊ฒฝ์šฐ๊ฐ€ ๋Œ€๋ถ€๋ถ„์œผ๋กœ, ํ•ด์–‘์ƒ๋ฌผ์— ์ ํ•ฉํ•œ ํ•ด์–‘์ƒํƒœํ™˜๊ฒฝ์„ ์กฐ์„ฑํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์ฝ˜ํฌ๋ฆฌํŠธ ๊ฐ•์•Œ์นด๋ฆฌ์„ฑ์„ ์ €๊ฐํ•˜๋Š” ์—ฐ๊ตฌ๊ฐ€ ์š”๊ตฌ๋˜๊ณ  ์žˆ๋‹ค.

๋”ฐ๋ผ์„œ ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” 3D ํ”„๋ฆฐํ„ฐ๋กœ ์ œ์ž‘๋˜๋Š” ์ธ๊ณต์–ด์ดˆ์šฉ ์ €์•Œ์นผ๋ฆฌ ๋ชจ๋ฅดํƒ€๋ฅด ๋ฐฐํ•ฉ์„ ๋„์ถœํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์‚ฐ์—…๋ถ€์‚ฐ๋ฌผ์˜ ์ ์šฉ ๊ฐ€๋Šฅ์„ฑ์„ ํ‰๊ฐ€ํ•˜๊ณ  ์ €์•Œ์นผ๋ฆฌ ๋ชจ๋ฅดํƒ€๋ฅด์˜ ์—ญํ•™์  ํŠน์„ฑ์„ ๋ถ„์„ํ•˜๊ณ  ํ‰๊ฐ€ํ•˜๊ณ ์ž ํ•œ๋‹ค.

Fig. 1 Artificial reefs produced by 3D printers
../../Resources/ksm/jksmi.2022.26.1.67/fig1.png

2. ๋ณธ ๋ก 

2.1 ์‹คํ—˜ ์žฌ๋ฃŒ

2.1.1 ์‹œ๋ฉ˜ํŠธ

๋ณธ ์‹คํ—˜์—์„œ ์‚ฌ์šฉํ•œ ์‹œ๋ฉ˜ํŠธ๋Š” ๊ตญ๋‚ด H์‚ฌ์˜ ๋ฐ€๋„ 3.15g/ใŽค, ๋ถ„๋ง๋„ 3,318ใŽ /g์˜ ๋ณดํ†ต ํฌํ‹€๋žœ๋“œ์‹œ๋ฉ˜ํŠธ๋ฅผ ์‚ฌ์šฉํ•˜์˜€๋‹ค

2.1.2 ์‹ค๋ฆฌ์นดํ“ธ ๋ฐ ํ”Œ๋ผ์ด์• ์‹œ

๋ณธ ์‹คํ—˜์—์„œ pH์ €๊ฐ ๋ฐ ๋‚ด๊ตฌ์„ฑ๋Šฅ ๊ฐœ์„ ์„ ๋ชฉ์ ์œผ๋กœ G์‚ฌ์˜ ์‹ค๋ฆฌ์นดํ“ธ๊ณผ K์‚ฌ์˜ ํ”Œ๋ผ์ด์• ์‹œ๋ฅผ ์‚ฌ์šฉํ•˜์˜€์œผ๋ฉฐ ๊ทธ ํŠน์„ฑ์€ ์•„๋ž˜์™€ ๊ฐ™๋‹ค.

Table 1 Physical properties of Silica fume

Density

(g/ใŽค)

Blaine

(ใŽ /g)

SiO2

Al2O3

Fe2O3

CaO

lg. loss

(%)

2.10

180,000

87.0

1.48

1.45

0.46

0.71

Table 2 Physical properties of Fly ash

Density

(g/ใŽค)

Blaine

(ใŽ /g)

SiO2

Al2O3

Fe2O3

CaO

lg. loss

(%)

2.14

3,750

56.3

21.5

6.85

5.13

4.1

2.1.3 ์•ŒํŒŒํ˜• ๋ฐ˜์ˆ˜์„๊ณ 

๋ณธ ์‹คํ—˜์—์„œ ์‹œ๋ฉ˜ํŠธ์˜ ์ˆ˜ํ™”๋ฐ˜์‘์œผ๋กœ ์ธํ•œ ์•Œ์นผ๋ฆฌ ์ €๊ฐ์„ ๋ชฉ์ ์œผ๋กœ ์‹œ๋ฉ˜ํŠธ ์ฝ”ํŒ… ํšจ๊ณผ๊ฐ€ ์žˆ์–ด pH ์ €๊ฐํšจ๊ณผ๊ฐ€ ์žˆ๋Š” Y์‚ฌ์˜ ์•ŒํŒŒํ˜• ๋ฐ˜์ˆ˜์„๊ณ ๋ฅผ ์‚ฌ์šฉํ•˜์˜€์œผ๋ฉฐ, ๊ทธ ํŠน์„ฑ์€ ์•„๋ž˜์™€ ๊ฐ™๋‹ค(Jang et al., 2013).

Table 3 Physical properties of CH

Density

(g/ใŽค)

Blaine

(ใŽ /g)

SiO2

Al2O3

Fe2O3

CaO

lg. loss

(%)

2.65

1,370

0.42

0.20

0.09

51.80

-

2.1.4 ์ž”๊ณจ์žฌ

๋ณธ ์‹คํ—˜์—์„œ ๊ตญ๋‚ด์—์„œ ์ƒ์‚ฐ๋˜๋Š” S์‚ฌ์˜ ์ž…๋„ 0.7~1.4mm์˜ ์ธ์กฐ๊ทœ์‚ฌ๋ฅผ ์‚ฌ์šฉํ•˜์˜€์œผ๋ฉฐ ๊ณจ์žฌ์˜ ๋ฌผ๋ฆฌ์  ์„ฑ์งˆ์„ Table 4์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

Table 4 Physical properties of fine aggregate

Aggregate

FM1)

SSD2)

(g/ใŽค)

Water

absorption ratio (%)

Unit volume

weight (kg/L)

#200 pass efficiency (%)

Silica sand

2.78

2.59

1.42

1.387

0.04

*1) F.M : Finenes modulus, 2) SSD : Surface dried specific gravity of aggregate

2.1.5 ํ˜ผํ™”์ œ

ํ˜ผํ™”์ œ๋กœ๋Š” ์‹œ๋ฉ˜ํŠธ ๋ถ„๋ฆฌ์ž‘์šฉ๊ณผ ๋ฏธ์„ธ๊ณต๊ธฐ ์—ฐํ–‰์œผ๋กœ ์šฐ์ˆ˜ํ•œ ์ž‘์—…์„ฑ๊ณผ ์•ˆ์ •์„ฑ์„ ๋ถ€์—ฌํ•˜๊ณ  ์ดˆ๊ธฐ ์Šฌ๋Ÿผํ”„ ์†์‹ค์„ ๋ฐฉ์ง€ํ•˜๋Š” ๊ตญ๋‚ด S์‚ฌ ์ œํ’ˆ์˜ ๊ณ ์„ฑ๋Šฅ ์œ ๋™ํ™”์ œ(Super plasticizer)๋ฅผ ์‚ฌ์šฉํ•˜์˜€์œผ๋ฉฐ, ๊ทธ ํŠน์„ฑ์€ Table 5์™€ ๊ฐ™๋‹ค.

Table 5 Properties of chemical admixture

Appearance

Density (g/ใŽค)

pH value

Light yellow liquid

1.02ยฑ0.2

5ยฑ2

2.2 ๋ฐฐํ•ฉ ๋ฐ ์‹œํ—˜์ฒด ์ œ์ž‘

2.2.1 ๋ฐฐํ•ฉ

์ธ๊ณต์–ด์ดˆ ์ ์šฉ์„ ์œ„ํ•œ ๋ชจ๋ฅดํƒ€๋ฅด์˜ pH์ €๊ฐ ์„ฑ๋Šฅ ๋ฐ ์—ญํ•™์ ์„ฑ๋Šฅํ‰๊ฐ€๋ฅผ ์œ„ํ•ด์„œ ์‹ค๋ฆฌ์นดํ“ธ, ํ”Œ๋ผ์ด์• ์‹œ, ์•ŒํŒŒํ˜• ๋ฐ˜์ˆ˜์„๊ณ ๋ฅผ ์‚ฌ์ „์‹คํ—˜์— ์˜ํ•ด ์„ ํƒ๋œ ๋น„์œจ๋กœ ๋ฐฐํ•ฉํ•˜์—ฌ ์‹œํ—˜ํ•˜๋˜, ๋ชจ๋ž˜/๋ฐ”์ธ๋”๋น„๋Š” 1.5, ๋ฐ˜์ฃฝ์งˆ๊ธฐ๋Š” ํ”Œ๋กœ์šฐ 190ยฑ5%๋กœ ๊ฒฐ์ •ํ•˜์˜€์œผ๋ฉฐ, ํ˜ผํ™”์ œ๋Š” ๊ฒฐํ•ฉ์žฌ๋Ÿ‰์˜ 0.5%๋ฅผ ํˆฌ์ž…ํ•˜์˜€๋‹ค. ์ด์— ๋Œ€ํ•œ ๋ฐฐํ•ฉํ‘œ๋Š” Table 6๊ณผ ๊ฐ™๋‹ค.

Table 6 Mixing design of mortar

Type

Target

flow(%)

S/B

C1)

SF2)

FA3)

ฮฑ-CH4)

Plain

190ยฑ5

1.5

100

-

-

-

Nonฮฑ-A

50

25

25

-

Nonฮฑ-B

36

16

48

-

Nonฮฑ-C

36

32

32

-

Nonฮฑ-D

36

48

16

-

ฮฑ-5

25

35

35

5

ฮฑ-15

25

30

30

15

ฮฑ-25

25

25

25

25

ฮฑ-35

25

20

20

35

*1) C : Cement, 2) SF : Silica fume, 3) FA : Fly ash, ใ€€4) ฮฑ -CH :ใ€€ฮฑ-calcium sulfateใ€€hemihydrate

2.2.2 ์‹œํ—˜์ œ ์ œ์ž‘

๊ณต์‹œ์ฒด๋Š” ๊ฐ ๋ฐฐํ•ฉ์š”์ธ์— ๋”ฐ๋ผ 40ร—40ร—160 mm์˜ ๊ณต์‹œ์ฒด๋ฅผ 3๊ฐœ์”ฉ ์ œ์ž‘ํ•˜์—ฌ 3์‹œ๊ฐ„๋™์•ˆ ์ „์–‘์ƒ์„ ์‹ค์‹œํ•œ ํ›„ ์˜จ๋„ 60โ„ƒ, ์Šต๋„ 100% ์กฐ๊ฑด์œผ๋กœ 6์‹œ๊ฐ„๋™์•ˆ ์ฆ๊ธฐ์–‘์ƒ์„ ์‹ค์‹œํ•˜์˜€๋‹ค.

2.3 ์‹คํ—˜๋ฐฉ๋ฒ•

2.3.1 ์••์ถ• ๋ฐ ํœจ๊ฐ•๋„ ์‹œํ—˜๋ฐฉ๋ฒ•

ํœจ ๋ฐ ์••์ถ•๊ฐ•๋„ ์‹œํ—˜์€ KS L ISO 679(์‹œ๋ฉ˜ํŠธ์˜ ๊ฐ•๋„ ์‹œํ—˜ ๋ฐฉ๋ฒ•)์— ๋”ฐ๋ผ 1,000 kN ์œ ์••์‹ ๊ฐ•๋„์‹œํ—˜๊ธฐ๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ๋ฐฐํ•ฉ์š”์ธ๋‹น 3ํšŒ์˜ ํœจ๊ฐ•๋„ ์‹œํ—˜๊ณผ 6ํšŒ์˜ ์••์ถ•๊ฐ•๋„ ์‹œํ—˜์„ ์‹ค์‹œํ•˜์—ฌ ํ‰๊ท ๊ฐ’์„ ์ธก์ •๊ฐ’์œผ๋กœ ํ•˜์˜€๋‹ค.

2.3.2 pH ์‹œํ—˜๋ฐฉ๋ฒ•

ํ˜„์žฌ ๊ตญ๋‚ด์—์„œ๋Š” ์ฝ˜ํฌ๋ฆฌํŠธ์˜ pH์ธก์ •์„ ์œ„ํ•œ ์‹œํ—˜๋ฐฉ๋ฒ•์€ ์ œ์‹œ๋œ ๋ฐ” ์—†๋‹ค. ์ด์— ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ํ๊ธฐ๋ฌผ๊ณต์ •์‹œํ—˜๊ธฐ์ค€ ์ค‘ ์ˆ˜์†Œ์ด์˜จ๋†๋„-์œ ๋ฆฌ์ „๊ทน๋ฒ•์„ ์ค€์šฉํ•˜์—ฌ ์‹œํ—˜์„ ํ•˜๋˜, ํ•ด๋‹น ์žฌ๋ น์—์„œ ์••์ถ•๊ฐ•๋„ ์‹œํ—˜ ํ›„ ํŒŒ์‡„๋œ ๋ชจ๋ฅดํƒ€๋ฅด ๊ณต์‹œ์ฒด๋ฅผ ๋ฌด์‡ ์ ˆ๊ตฌ๋ฅผ ์ด์šฉํ•˜์—ฌ ๋ถ„์‡„ํ•œ ํ›„ ์ž…๊ฒฝ 0.06mm ์ฒด๋ฅผ ํ†ต๊ณผํ•œ ๋ถ„๋ง์‹œ๋ฃŒ๋ฅผ ๋Œ€์ƒ์œผ๋กœ pH๋ฅผ ์ธก์ •ํ•˜์˜€๋‹ค.

pH์ธก์ •์€ ์ฒด๋ฅผ ํ†ต๊ณผํ•œ ์‹œ๋ฃŒ ๋ถ„๋ง 10g๊ณผ ์ฆ๋ฅ˜์ˆ˜ 25ml(pH 7~8)๋ฅผ 50ml Corning tube์— ๋„ฃ๊ณ  30๋ถ„๊ฐ„ ๊ต๋ฐ˜ํ•œ ํ›„ 10๋ถ„๊ฐ„ ๋ฐฉ์น˜ํ•˜์—ฌ ๊ทธ ํ˜„ํƒ์•ก์„ ์—ฌ๊ณผ์ง€(7ใŽ›)์— ํ†ต๊ณผ์‹œ์ผœ ์‹œ๋ฃŒ ์šฉ์•ก์œผ๋กœ ์‚ฌ์šฉํ•˜์˜€๋‹ค. pH์ธก์ •์€ ์‹œ๋ฃŒ๋‹น ์ด 3ํšŒ๋ฅผ ์‹ค์‹œํ•˜์—ฌ ํ‰๊ท ๊ฐ’์„ ๊ฒฐ๊ณผ๊ฐ’์œผ๋กœ ํ•˜์˜€๋‹ค.

2.3.3 ์—ผ์†Œ์ด์˜จ ์นจํˆฌ ์ €ํ•ญ์„ฑ

์‹œํ—˜์ฒด์˜ ์ œ์ž‘์€ ร˜ 100 ร— 200mm ์›์ฃผํ˜• ๊ณต์‹œ์ฒด๋ฅผ ์ œ์ž‘ํ•˜์—ฌ 3์‹œ๊ฐ„๋™์•ˆ ์ „์–‘์ƒ์„ ์‹ค์‹œํ•œ ํ›„ ์˜จ๋„ 60โ„ƒ, ์Šต๋„ 100% ์กฐ๊ฑด์œผ๋กœ 6์‹œ๊ฐ„๋™์•ˆ ์ฆ๊ธฐ์–‘์ƒํ•˜์˜€์œผ๋ฉฐ, ์žฌ๋ น28์ผ์— 50mm๊ธธ์ด๋กœ 4๋“ฑ๋ถ„ ์ ˆ๋‹จํ•˜์—ฌ ์ œ์ž‘ํ•˜์˜€๋‹ค. ์ œ์ž‘๋œ ์‹œํ—˜์ฒด๋Š” KS F 2711ใ€Œ์ „๊ธฐ ์ „๋„๋„์— ์˜ํ•œ ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ์—ผ์†Œ์ด์˜จ ์นจํˆฌ ์ €ํ•ญ์„ฑ ์‹œํ—˜ ๋ฐฉ๋ฒ•ใ€์— ์ค€ํ•˜์—ฌ Fig. 2์™€ ๊ฐ™์ด ์‹ค์‹œํ•˜์˜€๋‹ค.

Fig. 2 Chloride ion penetration resistance test
../../Resources/ksm/jksmi.2022.26.1.67/fig2.png

2.3.4 ๊ธธ์ด๋ณ€ํ™” ์‹œํ—˜๋ฐฉ๋ฒ•

์‹œํ—˜์ฒด์˜ ์ œ์ž‘์€ 40ร—40ร—160 mm ๊ฐ์ฃผํ˜• ๊ณต์‹œ์ฒด ์–‘์ชฝ ๋์— ์Šคํ„ฐ๋“œ๋ฅผ ๋งค๋ฆฝํ•˜์—ฌ ์ œ์ž‘ํ•˜์—ฌ 3์‹œ๊ฐ„๋™์•ˆ ์ „์–‘์ƒ์„ ์‹ค์‹œํ•œ ํ›„ ์˜จ๋„ 60โ„ƒ, ์Šต๋„ 100% ์กฐ๊ฑด์œผ๋กœ 6์‹œ๊ฐ„๋™์•ˆ ์ฆ๊ธฐ์–‘์ƒ์„ ์‹ค์‹œํ•˜์˜€๋‹ค. ๊ธธ์ด๋ณ€ํ™” ์ธก์ •์€ KS F 2424(๋ชจ๋ฅดํƒ€๋ฅด ๋ฐ ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ๊ธธ์ด๋ณ€ํ™” ์‹œํ—˜๋ฐฉ๋ฒ•)์— ๋”ฐ๋ผ ์ฝ˜ํ…ํŠธ ๊ฒŒ์ด์ง€ ๋ฐฉ๋ฒ•์œผ๋กœ ์ธก์ •ํ•˜์˜€๋‹ค.

Fig. 3 Length change test over time
../../Resources/ksm/jksmi.2022.26.1.67/fig3.png

2.4 ์‹คํ—˜๊ฒฐ๊ณผ

2.4.1 ์••์ถ•๊ฐ•๋„ ๋ฐ ํœจ๊ฐ•๋„

์ธ๊ณต์–ด์ดˆ ์ ์šฉ์„ ์œ„ํ•œ ์ €์•Œ์นผ๋ฆฌ ๋ชจ๋ฅดํƒ€๋ฅด์˜ ๊ฐ•๋„ ํŠน์„ฑ ํ‰๊ฐ€๊ฒฐ๊ณผ๋Š” Fig. 4 ๋ฐ Fig. 5์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ๋ณดํ†ตํฌํ‹€๋žœ๋“œ์‹œ๋ฉ˜ํŠธ๋งŒ์„ ์‚ฌ์šฉํ•œ Plain์˜ ๊ฒฝ์šฐ, 28์ผ๊นŒ์ง€ ๊ฐ•๋„๊ฐ€ ์ฆ๊ฐ€๋˜์–ด 46.8MPa๊นŒ์ง€ ๊ฐ•๋„๊ฐ€ ๋ฐœํ˜„๋˜์—ˆ๋‹ค. pH ์ €๊ฐ์„ ๋ชฉ์ ์œผ๋กœ ์‹ค๋ฆฌ์นดํ“ธ ๋ฐ ํ”Œ๋ผ์ด์• ์‹œ์˜ ํ˜ผ์ž…์— ๋”ฐ๋ผ์„œ๋Š” ๊ฐ•๋„ ๋ฐœํ˜„์ด Plain ๋Œ€๋น„ 27.99~ 67.31%๋กœ ํ˜ผ์ž…๋Ÿ‰ ์ฆ๊ฐ€์— ๋”ฐ๋ผ ๊ฐ•๋„ ๊ฐ์†Œ๊ฒฝํ–ฅ์ด ๋šœ๋ ทํ•˜์˜€๋‹ค. ํŠนํžˆ, ์‹ค๋ฆฌ์นดํ“ธ ํ˜ผ์ž…์— ๋”ฐ๋ผ ๊ฐ•๋„ ๊ฐ์†Œ๊ฒฝํ–ฅ์ด ๋” ์ปค์ง„ ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ์ด๋Š” ๋™์ผ ํ”Œ๋กœ๋ฅผ ๋ชฉํ‘œ๋กœ ๋ฐฐํ•ฉํ•˜์˜€์„ ๋•Œ, Plain ๋Œ€๋น„ ๋ถ„์ฒด๋Ÿ‰์ด ๋†’์€ ๋ฐฐํ•ฉ์—์„œ ํ˜ผํ•ฉ์ˆ˜๋Ÿ‰ ์ฆ๊ฐ€์— ๋”ฐ๋ผ ๊ฐ•๋„๊ฐ€ ๊ฐ์†Œ๋œ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

์•ŒํŒŒ๋ฐ˜์ˆ˜์„๊ณ ๋Š” ์‹œ๋ฉ˜ํŠธ์™€ ์ดˆ๊ธฐ์— ๊ฒฐํ•ฉํ•˜์—ฌ ์กฐ๊ธฐ๊ฐ•๋„ ํ™•๋ณด๊ฐ€ ์œ ๋ฆฌํ•œ ๊ฒƒ์œผ๋กœ ๋ณด๊ณ ๋˜๊ณ  ์žˆ๋‹ค(Lee et al., 2016;Park et al., 2006;shin et al., 2019). ๋ณธ ์—ฐ๊ตฌ์˜ ๋ฐฐํ•ฉ์กฐ๊ฑด์—์„œ ๋™์ผ ์‹œ๋ฉ˜ํŠธ ๋Œ€๋น„ ์•ŒํŒŒํ˜•๋ฐ˜์ˆ˜์„๊ณ  ํ˜ผ์ž…๋Ÿ‰์„ ์ฆ๊ฐ€์‹œ์ผฐ์„ ๋•Œ, ํ˜ผ์ž…๋Ÿ‰ ์ฆ๊ฐ€์— ๋”ฐ๋ผ ๊ฐ•๋„๋Š” ์ฆ๊ฐ€๋˜๋Š” ๊ฒƒ์œผ๋กœ ํ™•์ธ๋˜์—ˆ๋‹ค. ์•ŒํŒŒํ˜•๋ฐ˜์ˆ˜์„๊ณ ๋ฅผ ํ˜ผ์ž…ํ•˜์ง€ ์•Š์€ Nonฮฑ-A ๋Œ€๋น„ ์‹œ๋ฉ˜ํŠธ ๋น„์œจ์„ 30% ๊ฐ์†Œ์‹œํ‚จ ฮฑ-25, 35 ๋ฐฐํ•ฉ์—์„œ ๋™๋“ฑ์ด์ƒ์˜ ๊ฐ•๋„๊ฐ€ ํ™•๋ณด๋˜๋Š” ๊ฒƒ์œผ๋กœ ํ™•์ธ๋˜์—ˆ๋‹ค.

๋ฐฐํ•ฉ์กฐ๊ฑด๋ณ„ ํœจ๊ฐ•๋„ ํŠน์„ฑ์€ ์••์ถ•๊ฐ•๋„์™€ ์œ ์‚ฌํ•œ ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด์—ˆ์œผ๋ฉฐ, ์‹ค๋ฆฌ์นดํ“ธ, ํ”Œ๋ผ์ด์• ์‹œ ๋ฐ ์•ŒํŒŒํ˜•๋ฐ˜์ˆ˜์„๊ณ ์˜ ํ˜ผ์ž…์ด ํœจ๊ฐ•๋„ ํŠน์„ฑ์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์€ ์••์ถ•๊ฐ•๋„์™€ ๋™์ผํ•œ ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

ํ•ด์–‘๊ตฌ์กฐ๋ฌผ์— ๋Œ€ํ•œ ์••์ถ•๊ฐ•๋„ ๊ทœ์ •์„ ์‚ดํŽด๋ณด๋ฉด โ€˜ํ•ญ๋งŒ ๋ฐ ์–ดํ•ญ ์„ค๊ณ„๊ธฐ์ค€ใ†ํ•ด์„ค(MOF, 2017)โ€™์—์„œ ๋™๊ฒฐ์œตํ•ด์ž‘์šฉ์„ ๋ฐ›์ง€ ์•Š๋Š” ์ฒ ๊ทผ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ํ•ด์ค‘ํ™˜๊ฒฝํ•˜์˜ ์ตœ์†Œ ์„ค๊ณ„๊ธฐ์ค€์••์ถ•๊ฐ•๋„๋Š” 27MPa ์ด์ƒ์œผ๋กœ ์ œ์‹œํ•˜๊ณ  ์žˆ๊ณ , โ€˜์ธ๊ณต์–ด์ดˆ ํ‘œ์ค€์„ค๊ณ„ ๋ฐ ์ œ์ž‘ใ†์„ค์น˜ ๋“ฑ์— ๊ด€ํ•œ ์ง€์นจโ€™์— ๋”ฐ๋ฅด๋ฉด ์ฝ˜ํฌ๋ฆฌํŠธ์–ด์ดˆ์˜ ๋ ˆ๋ฏธ์ฝ˜๊ธฐ์ค€๊ฐ•๋„๋Š” 21MPa ์ด์ƒ์œผ๋กœ ๊ทœ์ •๋˜์–ด ์žˆ๋‹ค.

๋”ฐ๋ผ์„œ ์ด๋ฅผ ๊ณ ๋ คํ•˜์˜€์„ ๋•Œ ์ˆ˜์ค‘์— ์„ค์น˜๋˜๋Š” ์ธ๊ณต์–ด์ดˆ์˜ ์••์ถ•๊ฐ•๋„๋Š” ์ตœ์†Œ 27MPa์ด์ƒ์„ ๋งŒ์กฑํ•˜๋Š” ๊ฒƒ์ด ํƒ€๋‹นํ•˜๋ฏ€๋กœ, ฮฑ-25, ฮฑ-35๋ฐฐํ•ฉ์€ ์ธ๊ณต์–ด์ดˆ์šฉ ๋ชจ๋ฅดํƒ€๋ฅด๋กœ ์ ์šฉ ๊ฐ€๋Šฅํ•  ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

Fig. 4 Result of Compressive strength test
../../Resources/ksm/jksmi.2022.26.1.67/fig4.png
Fig. 5 Result of Flexural strength test
../../Resources/ksm/jksmi.2022.26.1.67/fig5.png

2.4.2 pH ์‹œํ—˜

์ธ๊ณต์–ด์ดˆ์šฉ ์ฝ˜ํฌ๋ฆฌํŠธ์—์„œ pH ๋ณ€ํ™”์— ๋”ฐ๋ฅธ ํ•ด์–‘์‹๋ฌผ์˜ ์ƒ์žฅ์„ฑ(๋ฟŒ๋ฆฌ ํ™œ์ฐฉ ๋ฐ ์˜์–‘์†Œ ํก์ˆ˜์„ฑ)์„ ๊ณ ๋ คํ•œ๋‹ค๋ฉด ์ฝ˜ํฌ๋ฆฌํŠธ ๋‚ดยท์™ธ๋ถ€์˜ ์ •ํ™•ํ•œ pH ์ธก์ • ๋ฐฉ๋ฒ•์ด ์š”๊ตฌ๋œ๋‹ค. ํ•˜์ง€๋งŒ ๊ธฐ์กด ์—ฐ๊ตฌ์—์„œ ์‚ฌ์šฉ๋œ ๋ฆฌ์นญ๋ฒ•์˜ ๊ฒฝ์šฐ ์ˆ˜๋ถ„๊ณผ ์ ‘์ด‰ํ•˜๋Š” ์ฝ˜ํฌ๋ฆฌํŠธ ์™ธ๋ถ€์˜ pH ์ธก์ •์— ๊ตญํ•œ๋  ์ˆ˜ ์žˆ์œผ๋ฉฐ(Lee et al., 2011; Kim et al., 2014), ์‹œ๊ฐ„์˜ ์ง€๋‚จ์— ๋”ฐ๋ฅธ ์•Œ์นผ๋ฆฌ์„ฑ๋ถ„์˜ ์šฉ์ถœ๋กœ ์ธํ•œ pH ๋ณ€ํ™”๊ฐ€ ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋‹ค. ๋”ฐ๋ผ์„œ ๋ณธ ์—ฐ๊ตฌ์—์„œ pH ์ธก์ •์€ ์ฝ˜ํฌ๋ฆฌํŠธ ๋‚ดยท์™ธ๋ถ€์˜ ๊ท ์งˆํ•œ pH ๊ฐ’์„ ์ธก์ •ํ•˜๊ธฐ ์œ„ํ•ด KS F 2103 ํ™์˜ pH ๊ฐ’ ์ธก์ •๋ฐฉ๋ฒ•์— ๋”ฐ๋ผ ์‹œ๋ฃŒ๋ฅผ ๋ฏธ๋ถ„์œผ๋กœ ๋ถ„์‡„ ํ›„ 30 g์„ ์ฑ„์ทจํ•˜๊ณ  ์ฆ๋ฅ˜์ˆ˜ 25 ml์™€ ํ˜ผํ•ฉํ•˜์—ฌ pH๋ฅผ ์ธก์ •ํ•˜์˜€๋‹ค.

์•ŒํŒŒํ˜• ๋ฐ˜์ˆ˜์„๊ณ  100% ํŽ˜์ด์ŠคํŠธ์˜ pH๋Š” ์žฌ๋ น์— ๊ด€๊ณ„์—†์ด ์•ฝ 6.7์ˆ˜์ค€์œผ๋กœ ๋ณด๊ณ ๋˜๊ณ  ์žˆ๋‹ค. ์ด๋ฅผ ํ™œ์šฉํ•˜๋ฉด, ๋ณดํ†ตํฌํ‹€๋žœ๋“œ์‹œ๋ฉ˜ํŠธ ๋งŒ์„ ์‚ฌ์šฉํ•œ ๋ฐฐํ•ฉ๋ณด๋‹ค ์šฐ์ˆ˜ํ•œ pH ์ €๊ฐํšจ๊ณผ๋ฅผ ๋ณด์ผ ์ˆ˜์žˆ์„ ๊ฒƒ์œผ๋กœ ํŒ๋‹จํ•œ๋‹ค.

์‹œํ—˜๊ฒฐ๊ณผ๋Š” Fig. 6์— ๋‚˜ํƒ€๋‚ด์—ˆ์œผ๋ฉฐ, ์žฌ๋ น์˜ ๊ฒฝ๊ณผ์™€ ์ƒ๊ด€์—†์ด Plain ๋ฐฐํ•ฉ์—์„œ๋Š” 12์ด์ƒ์˜ pH๋ฅผ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ๋ณดํ†ตํฌํ‹€๋žœ๋“œ์‹œ๋ฉ˜ํŠธ์˜ ๋ฐฐํ•ฉ๋น„์œจ ๊ฐ์†Œ๋ฅผ ์œ„ํ•ด ์‹ค๋ฆฌ์นดํ“ธ ๋ฐ ํ”Œ๋ผ์ด์• ์‹œ์˜ ํ˜ผ์ž…์œจ๋ณ„ pH๋ฅผ ์ธก์ •ํ•˜์˜€์„ ๋•Œ, ์ผ๋ถ€ pH๊ฐ€ ๊ฐ์†Œ๋˜๋Š” ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด๊ธฐ๋„ ํ•˜์˜€์ง€๋งŒ, ๋Œ€์ฒด์ ์œผ๋กœ 11~12 ์ •๋„์˜ pH๋ฅผ ๋‚˜ํƒ€๋‚ด์–ด ์ค‘์„ฑํ™”๋Š” ๋˜์ง€ ๋ชปํ•˜๋Š” ๊ฒƒ์œผ๋กœ ํ™•์ธ๋˜์—ˆ๋‹ค. ์•ŒํŒŒํ˜•๋ฐ˜์ˆ˜์„๊ณ  ํ˜ผ์ž…์— ๋”ฐ๋ฅธ pH๋ณ€ํ™”๋Ÿ‰ ๋ถ„์„๊ฒฐ๊ณผ, ์žฌ๋ น์˜ ๊ฒฝ๊ณผ์— ๋”ฐ๋ผ pH ๊ฐ์†Œ ๊ฒฝํ–ฅ์ด ํฐ ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ์œผ๋ฉฐ, ์•ŒํŒŒํ˜• ๋ฐ˜์ˆ˜์„๊ณ ์˜ ํ˜ผ์ž…๋Ÿ‰ ์ฆ๊ฐ€์— ๋”ฐ๋ผ์„œ๋„ ์•Œ์นผ๋ฆฌ๋„๊ฐ€ ๊ฐ์†Œ๋˜๋Š” ๊ฒƒ์œผ๋กœ ํ™•์ธ๋˜์—ˆ๋‹ค. ์ด๋Š” ๊ธฐ์กด ์—ฐ๊ตฌ๊ฒฐ๊ณผ์™€ ์œ ์‚ฌํ•œ ๊ฒฝํ–ฅ์œผ๋กœ์„œ(Kim et al., 2007; Park et al., 2007), ์‹œ๋ฉ˜ํŠธ ๋Œ€์ฒด๋กœ ์‹ค๋ฆฌ์นดํ“ธ, ํ”Œ๋ผ์ด์• ์‹œ๋ฅผ ํ˜ผ์ž…ํ•œ ์ƒํƒœ์—์„œ ์•ŒํŒŒํ˜•๋ฐ˜์ˆ˜์„๊ณ  ์‚ฌ์šฉ์‹œ ์ˆ˜์‚ฐํ™”์นผ์Š˜ ์ƒ์„ฑ์ด ์–ต์ œ๋˜๊ณ  ํ™ฉ์‚ฐ์นผ์Š˜์ด ์ƒ์„ฑ๋จ์— ๋”ฐ๋ผ pH๊ฐ€ ๊ฐ์†Œ๋œ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

Fig. 6 Result of pH variation
../../Resources/ksm/jksmi.2022.26.1.67/fig6.png

2.4.3 ์—ผ์†Œ์ด์˜จ์นจํˆฌ์ €ํ•ญ์„ฑ

์ธ๊ณต์–ด์ดˆ ์ œ์ž‘์šฉ ๋ชจ๋ฅดํƒ€๋ฅด์˜ ์•Œ์นผ๋ฆฌ์ €๊ฐ์„ ์œ„ํ•œ ๋ฐฐํ•ฉ์กฐ๊ฑด๋ณ„ ์—ผ์†Œ์ด์˜จ์นจํˆฌ์ €ํ•ญ์„ฑ ์‹œํ—˜๊ฒฐ๊ณผ๋Š” Fig. 7์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

์‹œ๋ฉ˜ํŠธ ๋Œ€์ฒด ํ˜ผํ™”์žฌ๋ฅผ ํ˜ผํ•ฉํ•˜์ง€ ์•Š์€ Plain ์กฐ๊ฑด์—์„œ๋Š” 7620C์˜ ๋†’์€ ํ†ต๊ณผ์ „ํ•˜๋Ÿ‰ ๊ฐ’์„ ๋‚˜ํƒ€๋‚ด์–ด ๋‹ค์†Œ ๋†’์€ ์—ผ์†Œ์ด์˜จ์นจํˆฌ์ €ํ•ญ์„ฑ์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์‹ค๋ฆฌ์นดํ“ธ ๋ฐ ํ”Œ๋ผ์ด์• ์‹œ ํ˜ผ์ž…์— ๋”ฐ๋ฅธ ์—ผ์†Œ์ด์˜จ์นจํˆฌ์ €ํ•ญ์„ฑ ๊ฐ’์„ ์ธก์ •ํ•œ ๊ฒฐ๊ณผ, ํ”Œ๋ผ์ด์• ์‹œ์˜ ๋น„์œจ์ด ์กฐ๊ธˆ ๋” ๋†’์€ ๊ฒฝ์šฐ์— ํ†ต๊ณผ์ „ํ•˜๋Ÿ‰๊ฐ’์ด ์ƒ๋Œ€์ ์œผ๋กœ ๋‚ฎ๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๊ณ , ์‹ค๋ฆฌ์นดํ“ธ์˜ ํ˜ผ์ž…๋น„์œจ 48% ์—์„œ๋Š” ๊ฐ€์žฅ ๋†’์€ ํ†ต๊ณผ์ „ํ•˜๋Ÿ‰์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์ด๋Š” ๋ธ”๋ ˆ์ธ๊ฐ’์ด ๋†’๊ณ  SiO2 ํ•จ๋Ÿ‰์ด ๋†’์€ ์ผ๋ฐ˜์ ์ธ ์‹ค๋ฆฌ์นดํ“ธ์„ ์ ์ •๋Ÿ‰ ์‚ฌ์šฉ์‹œ ์ฝ˜ํฌ๋ฆฌํŠธ ๋‚ด๋ถ€ ๋งคํŠธ๋ฆญ์Šค๋ฅผ ์น˜๋ฐ€ํ•˜๊ฒŒ ํ•˜์—ฌ ์—ผ์†Œ์ด์˜จ์นจํˆฌ์ €ํ•ญ์„ฑ์„ ๋†’๊ฒŒ ํ•˜์ง€๋งŒ, ์ผ์ •์‚ฌ์šฉ๋Ÿ‰ ์ด์ƒ์˜ ํ˜ผ์ž…์€ ๋ชจ๋ฅดํƒ€๋ฅด ๋ฏน์‹ฑ์‹œ ํ˜ผํ•ฉ์ˆ˜์˜ ์ฆ๊ฐ€๋ฅผ ์•ผ๊ธฐ ์‹œํ‚ค๊ณ , ๋ณธ ์—ฐ๊ตฌ์— ์ ์šฉํ•œ ์ €ํ’ˆ์งˆ ์‹ค๋ฆฌ์นดํ“ธ์˜ ๊ฒฝ์šฐ ๋‚ฎ์€ ๋ธ”๋ ˆ์ธ๊ฐ’์„ ๊ฐ€์ง€๊ธฐ ๋•Œ๋ฌธ์— ๋‚ด๊ตฌ์„ฑ์ด ๋‚ฎ์€ ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

์•ŒํŒŒ๋ฐ˜์ˆ˜์„๊ณ ์˜ ํ˜ผ์ž…๋Ÿ‰ ์ฆ๊ฐ€์— ๋”ฐ๋ผ์„œ๋Š” ํ†ต๊ณผ์ „ํ•˜๋Ÿ‰ ๊ฐ’์ด ๋‚ฎ์•„์ง€๋Š” ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด์–ด ฮฑ-35 ๋ฐฐํ•ฉ์—์„œ 3844C์˜ ๊ฐ€์žฅ ์šฐ์ˆ˜ํ•œ ์—ผ์†Œ์ด์˜จ์นจํˆฌ์ €ํ•ญ์„ฑ์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค. ์ด๋Ÿฌํ•œ ๊ฒฐ๊ณผ๋Š” ์••์ถ•๊ฐ•๋„ ์‹œํ—˜ ๊ฒฐ๊ณผ์™€ ์œ ์‚ฌํ•œ ๊ฒฝํ–ฅ์œผ๋กœ์„œ, ์ƒ๊ด€๊ด€๊ณ„๊ฐ€ ๋†’์€ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

Fig. 7 Result of chloride ion penetration resistance
../../Resources/ksm/jksmi.2022.26.1.67/fig7.png

2.4.4 ๊ธธ์ด๋ณ€ํ™”

์ธ๊ณต์–ด์ดˆ ์ œ์ž‘์‹œ ์ ์šฉ๋˜๋Š” ์ฝ˜ํฌ๋ฆฌํŠธ์˜ pH์ €๊ฐ์„ ๋ชฉ์ ์œผ๋กœ ํ˜ผํ•ฉ๋˜๋Š” ์‹ค๋ฆฌ์นดํ“ธ ๋ฐ ํ”Œ๋ผ์ด์• ์‹œ๋Š” ์žฌ๋ น์— ๋”ฐ๋ฅธ ๊ฑด์กฐ์ˆ˜์ถ•์ด ๋ฐœ์ƒ๋˜๋Š” ๊ฒƒ์œผ๋กœ ๋ณด๊ณ ๋˜๊ณ  ์žˆ๋‹ค. ๋”ฐ๋ผ์„œ ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ๋ชจ๋ฅดํƒ€๋ฅด์˜ ์ˆ˜์ถ•์— ๋”ฐ๋ฅธ ๋ณด์ƒ์„ ์œ„ํ•ด ๊ฒฝํ™”์‹œ ํŒฝ์ฐฝํŠน์„ฑ์„ ๋‚˜ํƒ€๋‚ด๋Š”(Lee et al., 2015) ์•ŒํŒŒํ˜• ๋ฐ˜์ˆ˜์„๊ณ ๋ฅผ ํ˜ผ์ž…ํ•˜์—ฌ ๊ธธ์ด๋ณ€ํ™”๋ฅผ ์ธก์ •ํ•˜์˜€์œผ๋ฉฐ, ๊ทธ ๊ฒฐ๊ณผ๋Š” Fig. 8์— ๋‚˜ํƒ€๋‚ธ๋ฐ”์™€ ๊ฐ™๋‹ค.

๋ชจ๋“  ๋ฐฐํ•ฉ์กฐ๊ฑด์—์„œ ์ดˆ๊ธฐ ๋ฏธ์„ธํ•œ ํŒฝ์ฐฝ์„ ๋‚˜ํƒ€๋‚ธ ํ›„ 28์ผ๊นŒ์ง€ ๊ธ‰๊ฒฉํ•œ ์ˆ˜์ถ•์„ ๋‚˜ํƒ€๋‚ด์—ˆ์œผ๋ฉฐ 56์ผ ์ดํ›„์—๋Š” ์™„๋งŒํ•˜๊ฒŒ ์ˆ˜๋ ดํ•˜๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚˜ ๊ธฐ์กด ์—ฐ๊ตฌ๊ฒฐ๊ณผ(Shin et al., 2019)์™€ ์œ ์‚ฌํ•œ ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

๋ณดํ†ตํฌํ‹€๋žœ๋“œ์‹œ๋ฉ˜ํŠธ๋ฅผ ๋‹จ๋…์œผ๋กœ ์‚ฌ์šฉํ•œ Plain๋ฐฐํ•ฉ ์กฐ๊ฑด์—์„œ๋Š” ์žฌ๋ น 56์ผ์— 254ร—10-6 ์˜ ์ˆ˜์ถ•์ด ๋ฐœ์ƒ๋˜์—ˆ์œผ๋ฉฐ, ์‹ค๋ฆฌ์นดํ“ธ ๋ฐ ํ”Œ๋ผ์ด์• ์‹œ ํ˜ผํ•ฉ์‹œ 268ร—10-6 ~ 384ร—10-6 ์˜ ์ˆ˜์ถ•์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ํŒฝ์ฐฝํŠน์„ฑ์„ ๊ฐ€์ง€๋Š” ์•ŒํŒŒํ˜•๋ฐ˜์ˆ˜์„๊ณ  ํ˜ผ์ž…์‹œ Pain๋ณด๋‹ค ์ž‘์€ ์ˆ˜์ถ•๋Ÿ‰์„ ๋‚˜ํƒ€๋‚ด์–ด 124ร—10-6 ~ 159ร—10-6 ์ •๋„๋กœ์„œ ์ˆ˜์ถ•๋Ÿ‰์ด ๊ฐ์†Œ๋จ์— ๋”ฐ๋ผ ๊ท ์—ด์ €๊ฐ ์„ฑ๋Šฅ๋„ ์šฐ์ˆ˜ํ•  ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

Fig. 8 Result of Length change test over time
../../Resources/ksm/jksmi.2022.26.1.67/fig8.png

3. ๊ฒฐ ๋ก 

๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” 3D ํ”„๋ฆฐํ„ฐ๋กœ ์ œ์ž‘๋˜๋Š” ์ธ๊ณต์–ด์ดˆ์šฉ ์ €์•Œ์นผ๋ฆฌ ๋ชจ๋ฅดํƒ€๋ฅด ๋ฐฐํ•ฉ์„ ๋„์ถœํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ๋ณดํ†ตํฌํ‹€๋žœ๋“œ์‹œ๋ฉ˜ํŠธ ๋Œ€์ฒด์žฌ ์ ์šฉ ๊ฐ€๋Šฅ์„ฑ์„ ํ‰๊ฐ€ํ•˜๊ณ  ์ €์•Œ์นผ๋ฆฌ ๋ชจ๋ฅดํƒ€๋ฅด์˜ ์—ญํ•™์  ํŠน์„ฑ ๋ฐ ๋‚ด๊ตฌ์„ฑ๋Šฅ์„ ํ‰๊ฐ€ํ•˜์˜€๋‹ค. ๊ทธ ๊ฒฐ๊ณผ๋ฅผ ์š”์•ฝํ•˜๋ฉด ๋‹ค์Œ๊ณผ ๊ฐ™๋‹ค.

1) ์ธ๊ณต์–ด์ดˆ ์ ์šฉ์„ ์œ„ํ•œ ์ €์•Œ์นผ๋ฆฌ ๋ชจ๋ฅดํƒ€๋ฅด์˜ ๊ฐ•๋„ ํŠน์„ฑ ํ‰๊ฐ€๊ฒฐ๊ณผ ๊ฒฐํ•ฉ์žฌ๋กœ ์‹œ๋ฉ˜ํŠธ๋งŒ ์‚ฌ์šฉํ•œ ๊ฒฝ์šฐ ๋Œ€๋น„ ์‹ค๋ฆฌ์นดํ“ธ๊ณผ ํ”Œ๋ผ์ด์• ์‹œ ํ˜ผํ•ฉ์‹œ ํ˜ผ์ž…๋Ÿ‰ ์ฆ๊ฐ€์— ๋”ฐ๋ผ ๊ฐ•๋„๋Š” ๊ฐ์†Œ๋˜์—ˆ์ง€๋งŒ, ์•ŒํŒŒํ˜•๋ฐ˜์ˆ˜์„๊ณ  ํ˜ผ์ž…์‹œ ๊ฐ•๋„๊ฐ€ ์ฆ๊ฐ€๋˜์–ด ์ธ๊ณต์–ด์ดˆ ํ’ˆ์งˆ๊ธฐ์ค€์ธ 27MPa๋ฅผ ํ™•๋ณดํ•  ์ˆ˜ ์žˆ๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค.

2) pH๋Š” OPC์˜ ์ˆ˜ํ™”๋กœ ์ธํ•ด ์ƒ์„ฑ๋œ Ca(OH)2์˜ ๋†’์€ ์ด์˜จํ™”ํŠน์„ฑ์— ๊ธฐ์ธํ•˜์—ฌ Plain์˜ ๊ฒฝ์šฐ 12์ด์ƒ์˜ ๋†’์€ pH๋ฅผ ๋‚˜ํƒ€๋‚ด์—ˆ๊ณ , ์‹ค๋ฆฌ์นดํ“ธ ๋ฐ ํ”Œ๋ผ์ด์• ์‹œ ๋Œ€์ฒด ํ˜ผ์ž…์‹œ pH๊ฐ€ ์ผ๋ถ€ ๊ฐ์†Œ๋˜์—ˆ๋‹ค. ์•ŒํŒŒํ˜•๋ฐ˜์ˆ˜์„๊ณ  ํ˜ผ์ž…์‹œ ์ˆ˜์‚ฐํ™”์นผ์Š˜ ์ƒ์„ฑ ์–ต์ œ์™€ ํ™ฉ์‚ฐ์นผ์Š˜ ์ƒ์„ฑ์œผ๋กœ ์ธํ•ด pH์ €๊ฐ ํšจ๊ณผ๊ฐ€ ์šฐ์ˆ˜ํ•œ ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค.

3) ํ•ด์ˆ˜์ค‘์— ์„ค์น˜๋˜๋Š” ์ธ๊ณต์–ด์ดˆ์˜ ๋‚ด๊ตฌ์„ฑ ํ™•๋ณด๋ฅผ ์œ„ํ•ด ์—ผ์†Œ์ด์˜จ์นจํˆฌ์ €ํ•ญ์„ฑ ์‹คํ—˜๊ฒฐ๊ณผ, ์‹ค๋ฆฌ์นดํ“ธ ๋ฐ ํ”Œ๋ผ์ด์• ์‹œ ํ˜ผ์ž…์‹œ ์ผ๋ถ€ ๋‚ด์—ผ์„ฑ์ด ๊ฐœ์„ ๋˜์—ˆ์œผ๋ฉฐ, ์•ŒํŒŒํ˜•๋ฐ˜์ˆ˜์„๊ณ  ๋ฅผ ํ˜ผํ•ฉ์‚ฌ์šฉํ•œ ฮฑ-35 ๋ฐฐํ•ฉ์—์„œ ํ†ต๊ณผ์ „ํ•˜๋Ÿ‰ 3844C์„ ๋‚˜ํƒ€๋‚ด, ๊ฐ€์žฅ ์šฐ์ˆ˜ํ•œ ์—ผ์†Œ์ด์˜จ์นจํˆฌ์ €ํ•ญ์„ฑ์„ ํ™•์ธํ•˜์˜€๋‹ค.

4)ใ€€์‹ค๋ฆฌ์นดํ“ธ ๋ฐ ํ”Œ๋ผ์ด์• ์‹œ ๋‹ค๋Ÿ‰ ํ˜ผ์ž…์— ๋”ฐ๋ผ ๋ฐœ์ƒํ•˜๋Š” ์ˆ˜์ถ• ๋ณด์ƒ์„ ๋ชฉ์ ์œผ๋กœ ํŒฝ์ฐฝ์ œ์ธ ์•ŒํŒŒํ˜•๋ฐ˜์ˆ˜์„๊ณ ๋ฅผ ์ ์šฉํ•˜์—ฌ ๊ธธ์ด๋ณ€ํ™”์œจ ์ธก์ •๊ฒฐ๊ณผ, ์•ŒํŒŒํ˜•๋ฐ˜์ˆ˜์„๊ณ  35% ๋Œ€์ฒด ํ˜ผ์ž…์‹œ OPC๋ฐฐํ•ฉ์กฐ๊ฑด๋ณด๋‹ค 33.5% ๊ฐœ์„ ๋œ ์ˆ˜์ถ•์ €ํ•ญ์„ฑ์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

5) ๋ณธ ์‹คํ—˜๋ฒ”์œ„์—์„œ ๊ฐ•๋„ ๋ฐ ๋‚ด๊ตฌ์„ฑ์„ ํ™•๋ณดํ•˜๋ฉด์„œ pH์ €๊ฐํšจ๊ณผ๊ฐ€ ๊ฐ€์žฅ ์šฐ์ˆ˜ํ•œ ๋ฐฐํ•ฉ์€ ฮฑ-25๋ฐฐํ•ฉ์œผ๋กœ ํŒ๋‹จ๋˜๋ฉฐ, ์ถ”ํ›„ ์ฝ˜ํฌ๋ฆฌํŠธ ์ ์šฉํ‰๊ฐ€์™€ ์ธ๊ณต์–ด์ดˆ ์‹œํ—˜์ฒด์— ๋Œ€ํ•œ ๊ฒ€ํ† ๊ฐ€ ํ•„์š”ํ•  ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

๊ฐ์‚ฌ์˜ ๊ธ€

์ด ๋…ผ๋ฌธ์€ 2020๋…„๋„ ์ •๋ถ€(๊ณผํ•™๊ธฐ์ˆ ์ •๋ณดํ†ต์‹ ๋ถ€)์˜ ์žฌ์›์œผ๋กœ ํ•œ๊ตญ์—ฐ๊ตฌ์žฌ๋‹จ์˜ ์ง€์›์„ ๋ฐ›์•„ ์ˆ˜ํ–‰๋œ ๊ธฐ์ดˆ์—ฐ๊ตฌ์‚ฌ์—…์ž„ (NRF-2020R1A2C1101465).

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