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  1. ํ•œ์–‘๋Œ€ํ•™๊ต ๊ฑด์„คํ™˜๊ฒฝ๊ณตํ•™๊ณผ ๋Œ€ํ•™์›์ƒ (Graduate Student, Department of Civil and Environmental Engineering, Hanyang University, Ansan 15588, Rep. of Korea)
  2. ํ•œ์–‘๋Œ€ํ•™๊ต ๊ฑด์„คํ™˜๊ฒฝ๊ณตํ•™๊ณผ ๊ต์ˆ˜ (Professor, Department of Civil and Environmental Engineering, Hanyang University, Ansan 15588, Rep. of Korea)



ํŽ˜๋กœ๋‹ˆ์ผˆ์Šฌ๋ž˜๊ทธ, SCM, ์‚ฐ์—…๋ถ€์‚ฐ๋ฌผ, ์ˆ˜ํ™”๋ฐ˜์‘, ๊ณต๊ทน๊ตฌ์กฐ
ferronickel slag, SCM, by-product, hydration, porosimetry

1. ์„œ ๋ก 

์ตœ๊ทผ์˜ ์ฝ˜ํฌ๋ฆฌํŠธ ์žฌ๋ฃŒ์— ๊ด€ํ•œ ์—ฐ๊ตฌ๋Š” โ€˜์—ดํ™”๋ฐฉ์ง€, ์ง€์†๊ฐ€๋Šฅํ•œ ์—๋„ˆ์ง€์ž์› ์‚ฌ์šฉ, ๋‹จ๊ฐ€์ ˆ๊ฐโ€™์˜ ์ฃผ์•ˆ์ ์— ๊ธฐ์ธํ•˜์—ฌ ์ด๋ค„์ง€๊ณ  ์žˆ๋‹ค. ๊ฑด์„ค ํ˜„์žฅ์—์„œ๋Š” ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ์ฃผ์š” ์—ดํ™”์ธ ์—ผ๋ถ„์นจํˆฌ, ํƒ„์‚ฐํ™”, ๊ฑด์กฐ์ˆ˜์ถ• ๋“ฑ์„ ๋ฐฉ์ง€ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ๊ณ ๋กœ์Šฌ๋ž˜๊ทธ, ์‹ค๋ฆฌ์นดํ“ธ, ํ”Œ๋ผ์ด์• ์‹œ ๋“ฑ์˜ ํ˜ผํ™”์žฌ๋ฅผ ์‹œ๋ฉ˜ํŠธ์— ํ˜ผ์ž…ํ•œ ๊ณ ์„ฑ๋Šฅ ์ฝ˜ํฌ๋ฆฌํŠธ๋ฅผ ์‚ฌ์šฉํ•˜๊ณ  ์žˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ์ด์— ๋Œ€ํ•œ ์ˆ˜์š”๊ฐ€ ๋†’์•„์ง์— ๋”ฐ๋ผ ํ˜ผํ™”์žฌ์˜ ์ž์›๊ณ ๊ฐˆ ๋ฐ ์ œํ’ˆ๋‹จ๊ฐ€ ์ƒ์Šน์ด๋ผ๋Š” ๋ฌธ์ œ์ ์ด ์•ผ๊ธฐ๋˜๊ณ  ์žˆ์–ด, ๊ทผ๋ž˜์—๋Š” ๊ธฐ์กด์˜ ํ˜ผํ™”์žฌ๋ฅผ ๋Œ€์ฒดํ•  ์ˆ˜ ์žˆ๋Š” ๊ด‘๋ฌผ์ž์›๊ณผ ์‚ฐ์—…๋ถ€์‚ฐ๋ฌผ์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๊ฐ€ ํ™œ๋ฐœํžˆ ์ด๋ค„์ง€๊ณ  ์žˆ๋‹ค. ๊ทธ์ค‘ ๊ตญ๋‚ด์™€ ์ค‘๊ตญ ๋“ฑ ์ฒ ๊ฐ•์‚ฐ์—…์ด ๋ฐœ๋‹ฌํ•œ ์ง€์—ญ์—์„œ ์ƒ์‚ฐ๋˜๋Š” ์‚ฐ์—…๋ถ€์‚ฐ๋ฌผ ์ค‘ ํ•˜๋‚˜์ธ ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ์˜ ํ˜ผํ™”์žฌ๋กœ์จ์˜ ์ ์šฉ์ด ์ฃผ๋ชฉ๋ฐ›๊ณ  ์žˆ๋‹ค.

ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ๋Š” ํ˜„์žฌ ์ผ๋ถ€ ๊ตญ๊ฐ€์—์„œ ๊ณจ์žฌ๋กœ ์ ์šฉํ•  ์ˆ˜ ์žˆ๋„๋ก ๊ทœ์ •(Japanese Standards Association 2016(7))์—์„œ ํ—ˆ์šฉํ•˜๊ณ  ์žˆ์ง€๋งŒ, MgO ์„ฑ๋ถ„์œผ๋กœ ์ธํ•ด ํŒฝ์ฐฝ์„ฑ์ด ์žˆ์–ด ๊ณจ์žฌ๋กœ ์‚ฌ์šฉ ์‹œ ์ ํ•ฉํ•˜์ง€ ์•Š๋‹ค๋Š” ์ฃผ์žฅ์ด ์ œ๊ธฐ๋˜๊ณ  ์žˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ์˜ ํŒฝ์ฐฝ์— ๋Œ€ํ•œ ์‹คํ—˜์  ๊ฒ€์ฆ์€ ๊ฑฐ์˜ ์ „๋ฌดํ•œ ์ƒํ™ฉ์ด๋ฉฐ, ์˜คํžˆ๋ ค ๋‹ค์–‘ํ•œ ๋น„ํ‘œ๋ฉด์ ์œผ๋กœ ์ƒ์‚ฐํ•  ์ˆ˜ ์žˆ๋Š” ์žฅ์ ์œผ๋กœ ์ธํ•ด ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ์˜ ํ˜ผํ™”์žฌ๋กœ์จ์˜ ์‚ฌ์šฉํ™•๋Œ€๋ฅผ ์œ„ํ•ด ๋ฌผ์„ฑํ‰๊ฐ€๋ฅผ ๊ธฐ๋ฐ˜์œผ๋กœ ํ•˜๋Š” ์—ฐ๊ตฌ๊ฐ€ ํ™œ๋ฐœํžˆ ์ด๋ค„์ง€๊ณ  ์žˆ๋‹ค.

ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ์— ๋Œ€ํ•œ ๋ฌผ์„ฑํ‰๊ฐ€ ์—ฐ๊ตฌ๋ฅผ ๋ณด๋ฉด, ๋ณดํ†ต ํฌํ‹€๋žœ๋“œ ์‹œ๋ฉ˜ํŠธ๋งŒ ์‚ฌ์šฉํ•˜์˜€์„ ๋•Œ๋ณด๋‹ค ํœจ๊ฐ•๋„๋Š” ์ฆ๊ฐ€ํ•˜๊ณ  ์••์ถ•๊ฐ•๋„๋Š” ๋น„์Šทํ•˜๊ฑฐ๋‚˜ ๋‚ฎ์€ ํŽธ์ด๋ฉฐ, ์—ผ์†Œ์ด์˜จ์˜ ์นจํˆฌ๋ฅผ ๊ฐ์†Œ์‹œํ‚ค๋Š” ์žฅ์ ์ด ์žˆ๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค(Komnitsas et al. 2009(10); Park 2017(14); Rahman et al. 2017(16); Huang et al. 2017(6)). ๋˜ํ•œ ์ดˆ๊ธฐ ์ˆ˜ํ™”์—ด์ด ๋‚ฎ์•„ ๊ฑด์กฐ์ˆ˜์ถ•์— ์œ ๋ฆฌํ•˜๊ณ (Yang et al. 2014(21)), ๋‚ดํ™”์„ฑ์ด ์šฐ์ˆ˜ํ•œ ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚˜(Yang et al. 2017(20)) ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ๋‚ด๊ตฌ์„ฑ ์ฆ์ง„์— ํšจ๊ณผ์ ์ธ ์žฌ๋ฃŒ๋กœ ์‚ฌ์šฉ๋  ๊ฐ€๋Šฅ์„ฑ์ด ์žˆ๋‹ค. ํ•œ ์—ฐ๊ตฌ์—์„œ๋Š” ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ๋ฅผ ์ฃผ ๊ตฌ์„ฑ์„ฑ๋ถ„์ธ MgO๊ฐ€ CaO์— ๋น„ํ•ด CO2๋ฅผ ๊ณ ์ •ํ™”ํ•  ์ˆ˜ ์žˆ๋Š” ์–‘์ด ๋งŽ์•„, MgCO3๋ฅผ ํ™œ์šฉํ•˜์—ฌ ๋‹จ์—ด์žฌ ๋ฐ ์—ฐ๋งˆ์žฌ ๋“ฑ์— ์ ์šฉํ•  ์ˆ˜ ์žˆ์„ ๊ฒƒ์œผ๋กœ ๋ถ„์„ํ–ˆ๋‹ค(Song et al. 2014(19)). ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ์˜ ์ ์ ˆํ•œ ํ˜ผ์ž…๋Ÿ‰์€ ๋ถ„๋ง๋„์— ๋”ฐ๋ผ 20โˆผ40% ์ˆ˜์ค€์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋Š”๋ฐ, ๋ณดํ†ตํฌํ‹€๋žœ๋“œ์‹œ๋ฉ˜ํŠธ์˜ ๋ถ„๋ง๋„์™€ ๋น„์Šทํ•œ ์ˆ˜์ค€์ธ 3,200โˆผ3,600 cm2/g์—์„œ๋Š” 20%์˜ ํ˜ผ์ž…๋Ÿ‰์ด ๋ฌผ์„ฑ ๋ฐœํ˜„์— ์ ์ ˆํ•œ ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๊ณ , 4,500โˆผ5,000 cm2/g์—์„œ๋Š” ์ตœ๋Œ€ 40%๊นŒ์ง€ ์‚ฌ์šฉ ๊ฐ€๋Šฅํ•  ๊ฒƒ์œผ๋กœ ํ‰๊ฐ€๋˜์–ด(Yang et al. 2014(21); Lemonis et al. 2015(12); Park 2017(14)), ์ œ์กฐ๊ณต์ •์—์„œ ๊ณ ๋ถ„๋ง๋„ ์ƒ์‚ฐ์„ ์œ„ํ•œ ๋‹จ๊ณ„๋ฅผ ์ค„์—ฌ ์›๊ฐ€๋ฅผ ์ ˆ๊ฐํ•  ์ˆ˜ ์žˆ๋Š” ์žฅ์ ์ด ์žˆ์„ ๊ฒƒ์œผ๋กœ ์ƒ๊ฐ๋œ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ๊ธฐ์กด ์—ฐ๊ตฌ์—์„œ๋Š” ๋ณดํ†ตํฌํ‹€๋žœ๋“œ์‹œ๋ฉ˜ํŠธ์™€ ๊ตฌ๋ณ„๋˜๋Š” ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ๊ธฐ์ดˆ๋ฌผ์„ฑ ๋ฐœํ˜„ ์›์ธ ๋˜๋Š” ์ˆ˜ํ™” ํŠน์„ฑ ๋Œ€ํ•œ ์—ฐ๊ตฌ๊ฐ€ ์ด๋ฃจ์–ด์ง€์ง€ ์•Š๊ณ  ์žˆ๋‹ค. ํŠนํžˆ X์„  ํ˜•๊ด‘๋ถ„์„์—์„œ ์ •๋Ÿ‰ํ™”๋˜๋Š” MgO์— ๋Œ€ํ•ด์„œ ์–ด๋–ค ํ™”ํ•ฉ๋ฌผ์˜ ํ˜•ํƒœ๋กœ ์ด๋ค„์ ธ ์žˆ๋Š”์ง€์— ๋Œ€ํ•œ ๊ธฐ์ดˆ ์กฐ์‚ฌ๋„ ๊ฑฐ์˜ ์ด๋ค„์ง€์ง€ ์•Š๊ณ  ์žˆ๋‹ค.

๋”ฐ๋ผ์„œ ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ๊ธฐ์กด ์—ฐ๊ตฌ์—์„œ ์ž…์ฆ๋œ ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ์˜ ์ฝ˜ํฌ๋ฆฌํŠธ ๋‚ด ํ˜ผํ™”์žฌ๋กœ์„œ์˜ ๋ฌผ๋ฆฌ์ , ํ™”ํ•™์  ํŠน์„ฑ ๋ฐœํ˜„ ์›์ธ์„ ์‹œ๋ฉ˜ํŠธ ํŽ˜์ด์ŠคํŠธ ๋‚ด์˜ ์ˆ˜ํ™”๊ฑฐ๋™๊ณผ ๊ณต๊ทน ํŠน์„ฑ์„ ๋ถ„์„ํ•˜์—ฌ ํ™•์ธํ•˜๊ณ ์ž ํ•œ๋‹ค. ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ ๋ฏธ๋ถ„๋ง์˜ ๋ฏธ์„ธ๊ตฌ์กฐ์™€ ์ˆ˜ํ™”ํŠน์„ฑ์„ ํŒŒ์•… ๋ฐ ์น˜ํ™˜์œจ์— ๋”ฐ๋ฅธ ์ˆ˜ํ™”๋„์˜ ์ •๋Ÿ‰ํ™”๋ฅผ ํ†ตํ•ด ํ‘œ์ค€ ์ œ์ •์˜ ๋’ท๋ฐ›์นจ ์ž๋ฃŒ๋กœ ํ™œ์šฉ๋˜์–ด ํ˜„์žฅ์—์„œ์˜ ์‚ฌ์šฉ์„ฑ์„ ํ™•๋Œ€ํ•  ์ˆ˜ ์žˆ์œผ๋ฉฐ, ์น˜ํ™˜์œจ์— ๋”ฐ๋ฅธ ๋‚ด๊ตฌ์ˆ˜๋ช… ์˜ˆ์ธก์ด ๊ฐ€๋Šฅํ•ด์ ธ ๋ชฉ์ ์— ๋งž๋Š” ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ์˜ ํ˜ผ์ž…๋Ÿ‰์„ ๊ฐ€์ด๋“œ๋ผ์ธ์œผ๋กœ ์ œ์‹œํ•  ์ˆ˜ ์žˆ๋‹ค. ๋ณธ ์—ฐ๊ตฌ์˜ ๊ฒฐ๊ณผ์™€ ๊ธฐ์กด ์—ฐ๊ตฌ๊ฒฐ๊ณผ๋ฅผ ๋ฐ”ํƒ•์œผ๋กœ ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ์— ๋Œ€ํ•œ ์‚ฐ์—…๊ธฐ์ค€์ด ๋งˆ๋ จ๋œ๋‹ค๋ฉด ๋ฒ”์„ธ๊ณ„์ ์œผ๋กœ ๊ฑด์„ค์‚ฐ์—…์— ์žฌ์ƒ์ž์› ํ™œ์šฉ์ด ํ™•๋Œ€๋  ์ˆ˜ ์žˆ๋‹ค.

์‹œ๋ฉ˜ํŠธ ๊ฒฝํ™”์ฒด์˜ ์ˆ˜ํ™”๋„๋Š” ๋‹ค์–‘ํ•œ ๋ฐฉ๋ฒ•์œผ๋กœ ํ™•์ธํ•  ์ˆ˜ ์žˆ๋Š”๋ฐ, RILEM TC 238-SCM ์œ„์›ํšŒ์˜ ๋ณด๊ณ (Scrivener et al. 2015(17))์— ์˜ํ•˜๋ฉด, ์‹œ๋ฉ˜ํŠธ ๋Œ€์ฒด ํ˜ผํ™”์žฌ์˜ ์ˆ˜ํ™”๋„๋ฅผ ์ธก์ •ํ•  ์ˆ˜ ์žˆ๋Š” ์ง์ ‘์ ์ธ ๋ฐฉ๋ฒ•์—๋Š” X์„  ํšŒ์ ˆ(XRD: X-ray diffraction) ๋ถ„์„, ์„ ํƒ์ถ”์ถœ๋ฒ•, ํ›„๋ฐฉ์‚ฐ๋ž€์ „์žํ˜„๋ฏธ๊ฒฝ(BSE: back-scattered electron) ์ด๋ฏธ์ง€ ๋ถ„์„, ํ•ต์ž๊ธฐ๊ณต๋ช…(NMR: nuclear magnetic resonance) ๋ถ„์„, ์—ด๋Ÿ‰์ธก์ • ๋ฐ ํ™”ํ•™์ ์ˆ˜์ถ•๋ฒ•, ์งˆ๋Ÿ‰ํ‰ํ˜•๋ฒ•์˜ 6๊ฐ€์ง€๊ฐ€ ์žˆ์œผ๋ฉฐ, ์ด๋Š” ํ˜ผํ™”์žฌ์˜ ์ข…๋ฅ˜์— ๋”ฐ๋ผ ํšจ๊ณผ๊ฐ€ ๋‹ฌ๋ฆฌ ๋‚˜ํƒ€๋‚˜๊ณ , ์Šฌ๋ž˜๊ทธ์˜ ๊ฒฝ์šฐ์—๋Š” XRD ๋ถ„์„๊ณผ BSE ์ด๋ฏธ์ง€ ๋ถ„์„ ๋ฐฉ๋ฒ•์„ ํ†ตํ•ด ๋น„๊ต์  ํ™•์‹คํ•œ ์ˆ˜ํ™”๋„์˜ ์ฒ™๋„๋กœ ์‚ผ์„ ์ˆ˜ ์žˆ๋‹ค๊ณ  ํ•˜์˜€๋‹ค. ๊ตญ๋‚ด์—๋Š” ์„ ํƒ์ถ”์ถœ๋ฒ•์„ ์ด์šฉํ•œ ๊ณ ๋กœ์Šฌ๋ž˜๊ทธ์˜ ์ˆ˜ํ™”๋„ ์—ฐ๊ตฌ์‚ฌ๋ก€๊ฐ€ ์žˆ๋‹ค(Kim et al. 2014(8)).

๋”ฐ๋ผ์„œ ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ ์›์žฌ๋ฃŒ์˜ XRD ๋ถ„์„์„ ํ† ๋Œ€๋กœ ํŽ˜์ด์ŠคํŠธ ๊ฒฝํ™”์ฒด์— ๋Œ€ํ•œ XRD ๋ถ„์„๊ณผ ์ฃผ์‚ฌ์ „์žํ˜„๋ฏธ๊ฒฝ(SEM: scanning electron microscopy, secondary electron) ๋ถ„์„์„ ์ˆ˜ํ–‰ํ•˜์—ฌ ์ƒ์„ฑ๋œ ์ˆ˜ํ™”๋ฌผ์„ ํ™•์ธํ•˜๊ณ , BSE ์ด๋ฏธ์ง€๋ฅผ ๋ถ„์„ํ•˜์—ฌ ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ์˜ ํ˜ผ์ž…๋Ÿ‰์— ๋”ฐ๋ฅธ ์ˆ˜ํ™”๋„๋ฅผ ์ถ”์ •ํ•˜์˜€์œผ๋ฉฐ, ์ด์— ๋”ฐ๋ฅธ ๋ฏธ์„ธ๊ณต๊ทน๊ตฌ์กฐ์˜ ์ฐจ์ด๋ฅผ ์ˆ˜์€์••์ž…๊ณต๊ทน๋ฒ•(MIP: mercury intrusion porosimetry)์„ ํ†ตํ•ด ๋ถ„์„ํ•˜์˜€๋‹ค. ์ดˆ๊ธฐ ์ˆ˜ํ™” ๊ฑฐ๋™์— ๋Œ€ํ•ด์„œ๋Š” ์‘๊ฒฐ์‹œ๊ฐ„์„ ์ธก์ •ํ•˜์—ฌ ์˜ˆ์ธกํ•˜์˜€๋‹ค.

2. ์žฌ๋ฃŒ ๋ฐ ์‹คํ—˜๋ฐฉ๋ฒ•

2.1 ์‹œํ—˜์žฌ๋ฃŒ

๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ๋ถ„๋ง๋„ 4,660 cm2/g, ๋น„์ค‘ 3.05์˜ ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ ๋ฏธ๋ถ„๋ง(์ดํ•˜ FNS)์„ ๋ถ„๋ง๋„ 3,240 cm2/g, ๋น„์ค‘ 3.14์ธ ๋ณดํ†ตํฌํ‹€๋žœ๋“œ์‹œ๋ฉ˜ํŠธ(์ดํ•˜ OPC)์— ํ˜ผ์ž…ํ•˜์—ฌ ์‚ฌ์šฉํ•˜์˜€๋‹ค. Fig. 1์— FNS์™€ OPC ์ž…๋„๋ถ„ํฌ๋ฅผ ๋‚˜ํƒ€๋‚ด์—ˆ์œผ๋ฉฐ, FNS์˜ ํ‰๊ท  ๋ฐ˜์ง€๋ฆ„์€ 3.39 ยตm๋กœ ์ธก์ •๋˜์—ˆ๊ณ  OPC์˜ ํ‰๊ท  ๋ฐ˜์ง€๋ฆ„์€ FNS์˜ ์•ฝ 1.8๋ฐฐ์— ๋‹ฌํ•˜๋Š” 6.16 ยตm๋กœ ์ธก์ •๋˜์—ˆ๋‹ค.

Fig. 1. Particle size distribution of FNS and OPC

../../Resources/kci/JKCI.2019.31.2.181/fig1.png

์‚ฌ์šฉํ•œ FNS์™€ OPC ์›์žฌ๋ฃŒ์˜ ์ฃผ์š” ํ™”ํ•™ ์กฐ์„ฑ์„ Table 1์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. FNS์˜ ์ฃผ์š” ์„ฑ๋ถ„์œผ๋กœ๋Š” MgO๊ฐ€ 40.45%, SiO2๊ฐ€ 40.46%๋กœ ๋งค์šฐ ๋†’๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๊ณ , CaO๋Š” 6.6%๋กœ ๋งค์šฐ ์ ๊ฒŒ ํฌํ•จ๋˜์–ด ์žˆ์Œ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค.

Table 1. Chemical composition of ferronickel slag (FNS) and OPC grain

Materials

Main oxide compound (%)

CaO

MgO

Al2O3

SiO2

Fe2O3

SO3

FNS

6.6

40.45

3.64

40.46

6.87

0.53

OPC

66.98

1.61

3.97

17.44

4.16

3.42

2.2 ์‹œํ—˜ํŽธ ์ œ์ž‘

2.2.1 ๋ฐฐํ•ฉ ์ข…๋ฅ˜

์‘๊ฒฐ์‹œ๊ฐ„ ์ธก์ •์— ์‚ฌ์šฉ๋œ ๊ตณ์ง€์•Š์€ ๋ชจ๋ฅดํƒ€๋ฅด ์ด์™ธ์˜ ๋ชจ๋“  ์‹œํ—˜ํŽธ์€ ํŽ˜์ด์ŠคํŠธ๋กœ ์ œ์ž‘๋˜์—ˆ์œผ๋ฉฐ, ๋ฐฐํ•ฉ๋น„์œจ์„ Table 2์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์‹œํ—˜ํŽธ์€ ๋ฏน์„œ๊ธฐ๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ 1๋ถ„๊ฐ„ ๊ฑด๋น„๋น”ํ•˜๊ณ  ๋ฐฐํ•ฉ์ˆ˜๋ฅผ ํˆฌ์ž…ํ•ด 3๋ถ„๊ฐ„ ๊ณ ์†์œผ๋กœ ํ˜ผํ•ฉํ•˜์˜€๋‹ค. ๋ฌผ-๊ฒฐํ•ฉ์žฌ ๋น„์œจ์€ 0.45๋กœ ๋™์ผํ•˜๊ฒŒ ํ•˜์˜€๋‹ค. ๋ชจ๋“  ์‹œํ—˜์— ๋Œ€ํ•ด์„œ๋Š” ๋ฏธ๋ถ„๋ง์˜ ์น˜ํ™˜์œจ์„ 10%, 30%, 50% ๋กœ ๋‘๊ณ , FNS๋ฅผ ํ˜ผ์ž…ํ•˜์ง€ ์•Š์€ OPC 100%์™€ ๋น„๊ตํ•˜์—ฌ 4์ข…์— ๋Œ€ํ•˜์—ฌ ์‹œํ—˜ํ•˜์˜€๋‹ค. ๋‹ค๋งŒ, SEM-SE, EDX๋ถ„์„์—์„œ๋Š” FNS 30% ์™€ 50% 2์ข…์— ๋Œ€ํ•ด์„œ๋งŒ ์ˆ˜ํ™”๋ฌผ ์ด๋ฏธ์ง€๋ฅผ ๋ถ„์„ํ•˜์˜€๋‹ค.

Table 2. Mix proportions (kg/m3)

Mix type

Water

OPC

FNS

Sand

Paste

OPC

562

1249

-

-

FNS 10 %

561

1123

124

-

FNS 30 %

560

871

373

-

FNS 50 %

558

620

620

-

Mortar

OPC

257

571

-

1199

FNS 10 %

257

513

57

1198

FNS 30 %

256

399

171

1197

FNS 50 %

256

285

285

1195

2.2.2 ์–‘์ƒ ์กฐ๊ฑด ๋ฐ ์ „์ฒ˜๋ฆฌ

๋ชจ๋“  ์‹œํ—˜์— ์‚ฌ์šฉ๋œ ์‹œํŽธ์€ ๋ช…์‹œ๋œ ์–‘์ƒ๊ธฐ๊ฐ„ ๋™์•ˆ ๊ธฐ๊ฑด(25 ยฑ 2 ยฐC)์œผ๋กœ ์–‘์ƒํ•˜์˜€์œผ๋ฉฐ, ์ „์ฒ˜๋ฆฌ ๊ณผ์ •์„ ๊ฑฐ์ณ ์•„์„ธํ†ค์— 24์‹œ๊ฐ„ ๋™์•ˆ ๋‹ด๊ฐ€ ์ˆ˜ํ™” ์ •์ง€์‹œ์ผฐ๋‹ค. ์ˆ˜ํ™” ์ •์ง€๋œ ์‹œํŽธ์€ ์ƒ๋Œ€์Šต๋„ 30%, ์˜จ๋„ 25 ยฑ 2 ยฐC์˜ ์ง„๊ณต ๋ฐ์‹œ์ผ€์ดํ„ฐ์—์„œ 48์‹œ๊ฐ„ ์ด์ƒ ๊ฑด์กฐ ์‹œํ‚จ ํ›„ ์‹œํ—˜ํ•˜์˜€๋‹ค.

XRD ์‹œํ—˜์—๋Š” ๊ฐ 7์ผ, 1๋…„๊ฐ„ ์–‘์ƒํ•œ ํŽ˜์ด์ŠคํŠธ ์‹œํ—˜ํŽธ์„ ๋ถ„์‡„ํ•˜์—ฌ ๋ถ„๋ง์˜ ์ž…๋„๊ฐ€ ์ง€๋ฆ„ 100 ยตm ์ดํ•˜๊ฐ€ ๋˜๋„๋ก ์ฒด์— ๊ฑธ๋Ÿฌ ์ค€๋น„ํ•˜์˜€๋‹ค.

SEM-SE, EDX ์‹œํ—˜์„ ์œ„ํ•œ ์‹œํŽธ์€ 10 ร— 10 ร— 10 mm ํŽ˜์ด์ŠคํŠธ๋กœ ์ œ์ž‘ํ•˜์—ฌ ๊ฐ 7์ผ, 1๋…„ ์–‘์ƒ ํ›„ ํด๋ฆฌ์‹ฑ ๊ณผ์ •์„ ๊ฑฐ์ณ ๋ถ„์„ํ•˜์˜€๋‹ค. 400โˆผ1,200 grit ํฌ๊ธฐ์˜ ์‚ฌํฌ๋ฅผ ์ž‘์€ ์ˆœ์„œ๋Œ€๋กœ ์‚ฌ์šฉํ•˜์—ฌ ํด๋ฆฌ์‹ฑํ•˜์˜€๋‹ค. ํด๋ฆฌ์‹ฑ ๊ธฐ๊ธฐ์˜ ์ž‘๋™์†๋„๋Š” 150 rpm, ์••๋ ฅ์€ 10 Pa๋กœ ํ•˜์˜€๋‹ค.

์ˆ˜ํ™”๋„ ๋ถ„์„(SEM-BSE)๊ณผ ๋ฏธ์„ธ๊ณต๊ทน๊ตฌ์กฐ ๋ถ„์„(MIP)์„ ์œ„ํ•œ ์‹œํ—˜์—๋Š” 28์ผ ์–‘์ƒํ•œ ์‹œํŽธ์„ ์‚ฌ์šฉํ•˜์˜€๋‹ค. SEM-BSE ์ธก์ •์„ ์œ„ํ•œ ์‹œํŽธ ์ „์ฒ˜๋ฆฌ๋Š” ์ƒ๊ธฐ SEM-SE ์‹œํŽธ ์ค€๋น„์™€ ๋™์ผํ•˜๊ฒŒ ํ•˜์˜€์œผ๋ฉฐ, MIP ์‹œํ—˜ํŽธ์€ ์–‘์ƒ ํ›„ 5 ร— 5 ร— 5 mm ์ •๋„์˜ ํฌ๊ธฐ๋กœ ์ ˆ๋‹จํ•˜์—ฌ 5 g ๊ฐ€๋Ÿ‰ ์ค€๋น„ํ•˜์˜€๋‹ค.

2.3 ์‹คํ—˜๋ฐฉ๋ฒ•

๋ณธ ์—ฐ๊ตฌ์—์„œ ์ˆ˜ํ–‰๋œ ์‹คํ—˜์€ FNS์˜ ์ˆ˜ํ™”๋ฌผ ํŒŒ์•…, FNS์˜ ์ˆ˜ํ™”๋„ ๋ถ„์„, FNS์˜ ๊ณต๊ทน๋ถ„ํฌ ํŒŒ์•…์„ ์œ„ํ•˜์—ฌ ๊ณ ์•ˆ๋˜์—ˆ์œผ๋ฉฐ, ๊ฐ ๋‹จ๊ณ„์— ๋”ฐ๋ผ ์‹ค์‹œํ•œ ์‹คํ—˜์— ๋Œ€ํ•œ ๊ฐœ์š”๋„๋ฅผ Fig. 2์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

Fig. 2. Outline of the performed experiment

../../Resources/kci/JKCI.2019.31.2.181/fig2.png

2.3.1 XRD, SEM-SE, EDX

FNS์˜ ์ˆ˜ํ™” ์ƒ์„ฑ๋ฌผ์„ ํ™•์ธํ•˜๊ธฐ ์œ„ํ•ด ๊ฒฐ์ •์ƒ์— ๋Œ€ํ•œ ๋ถ„์„์ด ๊ฐ€๋Šฅํ•œ XRD ๋ถ„์„์„ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. ์ฑ„์ทจํ•œ ๋ถ„๋ง ์•ฝ 1 g์„ ์Šค์บ”๊ฐ๋„ 5โˆผ65ยฐ, ์ธก์ •์†๋„ 2.0ยฐ/min์˜ ์กฐ๊ฑด์œผ๋กœ ์ธก์ •ํ•˜์˜€๋‹ค. ์ธก์ •๋œ ํ”ผํฌ๋Š” ์†Œํ”„ํŠธ์›จ์–ด์ธ PDXL๋กœ ๋ถ„์„ํ•˜์—ฌ ์กด์žฌํ•˜๋Š” ๋ฌผ์งˆ๋“ค์„ ํ™•์ธํ•˜์˜€๋‹ค. ๊ฐ๊ธฐ ๋‹ฌ๋ฆฌ ์ฑ„์ทจํ•œ ์‹œ๋ฃŒ๋ฅผ 3ํšŒ ์ธก์ •ํ•˜์—ฌ ๋ฐ˜๋ณต ์‹œํ—˜ํ•˜์˜€์œผ๋ฉฐ ๋Œ€ํ‘ฏ๊ฐ’์„ ๋ณธ๋ฌธ์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

XRD ๋ถ„์„์„ ํ†ตํ•ด ํ™•์ธ๋œ FNS ์ˆ˜ํ™”๋ฌผ ์ค‘ OPC์˜ ์ˆ˜ํ™”๋ฌผ์—์„œ๋Š” ๋ฐœ๊ฒฌ๋˜์ง€ ์•Š๋Š” ์ˆ˜ํ™”๋ฌผ๊ณผ FNS ๋ฏธ์ˆ˜ํ™”๋ฌผ์— ๋Œ€ํ•ด์„œ ๊ฐ€์‹œ์ ์œผ๋กœ ๋ฏธ์„ธ๊ตฌ์กฐ๋ฅผ ํ™•์ธํ•˜๊ธฐ ์œ„ํ•ด SEM-SE(secondary electron) ๋ชจ๋“œ๋กœ x 2,000, x10,000 ๋ฐฐ์œจ์˜ ์ด๋ฏธ์ง€๋ฅผ ์ดฌ์˜ํ•˜์˜€๋‹ค. ์‹œํ—˜ํŽธ์€ ๋ฐฐํ•ฉ ๋ณ„๋กœ 3๊ฐœ์”ฉ ์ค€๋น„ํ•˜์—ฌ ๋žœ๋คํ•˜๊ฒŒ ์ด๋ฏธ์ง€๋ฅผ ์ดฌ์˜ํ•˜์˜€๋‹ค. ๊ธฐ๊ธฐ ์ž‘๋™ ์‹œ ๋ถ€๊ฐ€ ์ „์••์€ 20 kV์˜€์œผ๋ฉฐ, ์ธก์ • ๊ฑฐ๋ฆฌ๋Š” 12.3 mm๋กœ ๋‘์–ด ์ดˆ์ ๊ฑฐ๋ฆฌ๋ฅผ ๋งž์ถ”์—ˆ๋‹ค.

SE ๋ชจ๋“œ๋กœ ์–ป์€ ์ด๋ฏธ์ง€์—์„œ ํ•ด๋‹น ์ˆ˜ํ™”๋ฌผ์˜ ํ™”ํ•™์  ์กฐ์„ฑ์„ ์•Œ์•„๋ณด๊ธฐ ์œ„ํ•˜์—ฌ EDX(energy dispersive X-ray spectroscopy)๋ฅผ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. EDX ๋ถ„์„ ๋ฐ์ดํ„ฐ๋กœ๋ถ€ํ„ฐ ํ•ด๋‹น ๋ฌผ์งˆ์„ ๊ตฌ์„ฑํ•˜๊ณ  ์žˆ๋Š” ์›์†Œ๋ฅผ ์ •๋Ÿ‰์ ์œผ๋กœ ๋ถ„์„ํ•  ์ˆ˜ ์žˆ๊ณ , ํ™”ํ•ฉ๋ฌผ์˜ ํ˜•ํƒœ๋ฅผ ์œ ์ถ”ํ•ด๋ณผ ์ˆ˜ ์žˆ๋‹ค.

2.3.2 ์‘๊ฒฐ์‹œ๊ฐ„

FNS ๋ชจ๋ฅดํƒ€๋ฅด์˜ ์‘๊ฒฐ์‹œ๊ฐ„ ์ธก์ •์€ KS F 2436(Korean Standards Association 2017)์— ์˜๊ฑฐํ•˜์—ฌ ์›ํ˜•๊ณต์‹œ์ฒด(ร˜150 ร— 150 mm)์— ํƒ€์„ค ํ›„ ์˜จ๋„ 20 ยฑ 2 ยฐC, ์ƒ๋Œ€์Šต๋„ 60 ยฑ 5%์˜ ์‹คํ—˜์‹ค ๋Œ€๊ธฐ ์กฐ๊ฑด์—์„œ ์‹คํ—˜ํ•˜์˜€๋‹ค. ๊ด€์ž…์ €ํ•ญ์นจ์„ ์‚ฌ์šฉํ•˜์—ฌ ์••๋ ฅ์„ ์ธก์ •ํ•˜๊ณ  ์นจ์˜ ๋ฉด์ ์œผ๋กœ ๋‚˜๋ˆˆ ์ €ํ•ญ๊ฐ’์ด 3.5 MPa์ผ ๋•Œ๋ฅผ ์ดˆ๊ฒฐ, 28 MPa์ผ ๋•Œ๋ฅผ ์ข…๊ฒฐ ์‹œ๊ฐ„์œผ๋กœ ์‚ฐ์ •ํ•˜์˜€๋‹ค. 3ํšŒ์”ฉ ์ธก์ •ํ•œ ํ‰๊ท ๊ฐ’์„ ๊ฐ ๋ฐฐํ•ฉ์˜ ์‘๊ฒฐ์‹œ๊ฐ„์œผ๋กœ ์‚ฐ์ •ํ•˜์˜€๋‹ค.

2.3.3 ์ˆ˜ํ™”๋„: SEM-BSE ์ด๋ฏธ์ง€ ๋ถ„์„

FNS์˜ ์น˜ํ™˜๋Ÿ‰์— ๋”ฐ๋ฅธ ์‹œ๋ฉ˜ํŠธ ํŽ˜์ด์ŠคํŠธ์˜ ์ˆ˜ํ™”๋„๋ฅผ ๋น„๊ตํ•˜๊ธฐ ์œ„ํ•ด BSE ๋ชจ๋“œ๋กœ SEM ์ด๋ฏธ์ง€๋ฅผ ์ดฌ์˜ํ•˜๊ณ  MATLAB์œผ๋กœ ๋ถ„์„ํ•˜์˜€๋‹ค. ์‹œํŽธ์€ ๋ฐฐํ•ฉ์ข…๋ฅ˜์— ๋”ฐ๋ผ 3๊ฐœ๋ฅผ ์ค€๋น„ํ•˜์˜€๋‹ค. 500๋ฐฐ๋กœ ์ดฌ์˜ํ•œ BSE ์ด๋ฏธ์ง€๋Š” ์ „์ฒด์˜์—ญ์— ๋Œ€ํ•ด์„œ MATLAB์„ ์ด์šฉํ•˜์—ฌ gray scale(255 scale)๋กœ segment ํ•˜์˜€๋Š”๋ฐ, ์ž„๊ณ„์ ์„ 79, 119, 140์œผ๋กœ ๋‘์–ด ๋‚˜๋‰˜๋Š” ๊ตฌ๊ฐ„์— ๋”ฐ๋ผ ๊ณต๊ทน, ๊ฒ” ์ˆ˜ํ™”๋ฌผ, ๊ฒฐ์ •์งˆ ์ˆ˜ํ™”๋ฌผ, ๋ฏธ์ˆ˜ํ™”๋ฌผ๋กœ ๊ตฌ๋ถ„ํ•˜๊ณ , ๊ฐ ์˜์—ญ์ด ์ฐจ์ง€ํ•˜๋Š” ๋ฉด์ ์„%๋กœ ๊ณ„์‚ฐํ•˜์˜€๋‹ค. ์ž„๊ณ„์ ์€ Kocaba et al.(2012(9))์—์„œ ์ œ์‹œํ•œ ์Šฌ๋ž˜๊ทธ ์‹œ๋ฉ˜ํŠธ์˜ gray scale ํžˆ์Šคํ† ๊ทธ๋žจ์„ ๊ธฐ๋ฐ˜์œผ๋กœ ๊ฐ ์˜์—ญ์„ ๊ตฌ๋ถ„ํ•  ์ˆ˜ ์žˆ๋Š” ์ ์„ ์„ ์ •ํ•˜์˜€๋‹ค. ๋žœ๋คํ•˜๊ฒŒ ์–ป์€ BSE ์ด๋ฏธ์ง€๋ฅผ 30์žฅ์”ฉ MATLAB์œผ๋กœ ๋ถ„์„ํ•˜์—ฌ ๊ตฌ๊ฐ„๋ณ„ ํ‰๊ท ๊ฐ’์ด ์ˆ˜๋ ดํ•  ์ˆ˜ ์žˆ๋„๋ก ํ•˜์˜€๋‹ค. Fig. 3์— FNS 30% ์‹œํŽธ์˜ BSE ์ด๋ฏธ์ง€๋ฅผ MATLAB์„ ํ†ตํ•ด ๊ตฌ๊ฐ„ ๋ณ„๋กœ mappingํ•œ ์˜ˆ์‹œ๋ฅผ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. BSE ์› ์ด๋ฏธ์ง€์— ๋Œ€ํ•œ ๊ฐ ํ”ฝ์…€์˜ gray scale ๊ฐ’์„ ์ž„๊ณ„์ ์„ ๊ธฐ์ค€์œผ๋กœ ๋‚˜๋ˆ  ๊ฐ ์˜์—ญ์— ํ•ด๋‹นํ•˜๋Š” ํ”ฝ์…€๋งŒ์„ ๊ฒ€์ •์ƒ‰์œผ๋กœ ํ‘œํ˜„ํ•œ ๊ฒƒ์„ Fig. 3(b)์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

Fig. 3. Mapping of FNS hydration product from BSE image using MATLAB: transform grayscale to binarization mapping: original BSE image (left), binary image (right)

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2.3.4 ๊ณต๊ทน๋ถ„ํฌ

FNS ํŽ˜์ด์ŠคํŠธ์˜ ๊ณต๊ทน๊ตฌ์กฐ๋Š” MIP ์‹œํ—˜์„ ํ†ตํ•ด ๋ฐฐํ•ฉ๋ณ„๋กœ 3ํšŒ ๋ถ„์„ํ•˜๊ณ  ๋Œ€ํ‘ฏ๊ฐ’์„ ๋ณธ๋ฌธ์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ํŽ˜๋„คํŠธ๋กœ๋ฏธํ„ฐ๊ฐ€ ๊ฐ€๋“ ์ฐฐ ์ˆ˜์ค€์œผ๋กœ ์•ฝ 4โˆผ5 g์˜ ์‹œํŽธ์„ ๋‹ด์•„ ์ง„๊ณต์ƒํƒœ๊ฐ€ ๋˜๋„๋ก ๋ฐ€๋ด‰ํ•˜๊ณ  ์†Œ์ˆ˜์  ๋„ท์งธ ์ž๋ฆฌ๊นŒ์ง€ ๋ฌด๊ฒŒ๋ฅผ ์ธก์ •ํ•œ ํ›„ ๊ธฐ๊ธฐ๋ฅผ ์ž‘๋™ํ•˜์˜€๋‹ค. ์ˆ˜์€์˜ ์นจํˆฌ ์••๋ ฅ์€ ์ €์•• 0.51 psia๋ถ€ํ„ฐ ๊ณ ์•• 33,000 psia๊นŒ์ง€ ๋†’์—ฌ ์ธก์ •ํ•˜์˜€๋‹ค. ์นจํˆฌ ์••๋ ฅ์— ๋”ฐ๋ฅธ ๊ณต๊ทน์˜ ์ง€๋ฆ„์€ ๋‹ค์Œ์˜ Washburn ์‹์„ ์ด์šฉํ•ด ๊ตฌํ•ด์ง„๋‹ค.

(1)
$d = -\dfrac{4\gamma\cos\theta}{P}$

์—ฌ๊ธฐ์„œ, d๋Š” ๊ณต๊ทน ์ง€๋ฆ„ (m), $\gamma$๋Š” ํ‘œ๋ฉด์žฅ๋ ฅ (N), $\theta$๋Š” ์ˆ˜์€๊ณผ์˜ ์ ‘์ด‰๊ฐ, P๋Š” ๊ฐ€์••๋œ ์••๋ ฅ (MPa)์„ ์˜๋ฏธํ•œ๋‹ค.

Midness et al. (2003(13))์€ ๊ณต๊ทน์˜ ํฌ๊ธฐ์— ๋”ฐ๋ผ ๊ทธ ์ข…๋ฅ˜๋ฅผ ๋‹ค์Œ๊ณผ ๊ฐ™์ด ๋ถ„๋ฅ˜ํ•˜์˜€๋‹ค: ๋งคํฌ๋กœ๊ณต๊ทน(macropore: >10 ยตm); ํฐ ๋ชจ์„ธ๊ด€(large capillary: 0.5โˆผ10 ยตm); ์ž‘์€ ๋ชจ์„ธ๊ด€(small capillary: 0.01โˆผ0.5 ยตm); ๊ฒ”(gel: <0.01 ยตm). ๋ณธ๋ฌธ์—์„œ๋„ ์ด ๋ถ„๋ฅ˜์— ๋”ฐ๋ผ ๊ณต๊ทน์˜ ์ข…๋ฅ˜๋ฅผ ๊ตฌ๋ถ„ํ•˜์—ฌ ํ‘œ๊ธฐํ•˜๊ธฐ๋กœ ํ•œ๋‹ค.

3. ์‹คํ—˜๊ฒฐ๊ณผ ๋ฐ ๊ณ ์ฐฐ

3.1 FNS์˜ ์ˆ˜ํ™”์ƒ์„ฑ๋ฌผ

3.1.1 XRD ๋ถ„์„

FNS ํŽ˜์ด์ŠคํŠธ์˜ ์ˆ˜ํ™”ํŠน์„ฑ์„ ์•Œ์•„๋ณด๊ธฐ ์œ„ํ•œ XRD ์ปค๋ธŒ ๋ถ„์„์— ์•ž์„œ, FNS ๋ฏธ๋ถ„๋ง ์›์žฌ๋ฃŒ์— ๋Œ€ํ•œ XRD ์ปค๋ธŒ๋ฅผ ๋ถ„์„ํ•˜์—ฌ ์ˆ˜ํ™”๋ฌผ๋กœ ๊ฒ€์ถœ ๊ฐ€๋Šฅํ•œ ์›์†Œ๋ฅผ ์ถ”๋ ค๋ƒˆ๋‹ค. Fig. 4์— ๋‚˜ํƒ€๋‚œ ๋ฐ”์™€ ๊ฐ™์ด FNS ๋ฏธ๋ถ„๋ง์˜ ๋Œ€๋ถ€๋ถ„์„ ๊ตฌ์„ฑํ•˜๊ณ  ์žˆ๋Š” ๊ฒƒ์€ forsterite (Mg2SiO4)์™€ iron silicate(Fe2SiO4)์˜€๋‹ค. Q-XRD๋ฅผ ํ†ตํ•œ ์ •๋Ÿ‰๋ถ„์„ ์‹œ forsterite๊ฐ€ ์•ฝ 93%, iron silicate๊ฐ€ ์•ฝ 6% ์ •๋„๋กœ ๋‚˜ํƒ€๋‚ฌ๊ธฐ ๋•Œ๋ฌธ์— forsterite์˜ ์ˆ˜ํ™”๋ฐ˜์‘์ด FNS์˜ ์ฃผ๋œ ์ˆ˜ํ™”๋ฐ˜์‘์ผ ๊ฒƒ์ด๋ผ๊ณ  ํŒ๋‹จ๋œ๋‹ค. Forsterite๋Š” pH๊ฐ€ ๋‚ฎ์€ ํ™˜๊ฒฝ์—์„œ๋„ M-S-H (magnesium silicate hydrates, or forsterite hydrous: Mg2SiO4(OH)0.5)๋ฅผ ์ƒ์„ฑํ•˜๋‚˜ ์ƒ์˜จ์—์„œ๋Š” ๋ฐ˜์‘์ด ๋งค์šฐ ๋Š๋ ค ์™„์ „ํ•œ ๋ฐ˜์‘์—๋Š” 2๋…„๊นŒ์ง€๋„ ์†Œ์š”๋œ๋‹ค(Bernard 2017(2)). Forsterite๋ฅผ ๊ตฌ์„ฑํ•˜๊ณ  ์žˆ๋Š” MgO์™€ SiO2๋Š” C-S-H์™€ ๋งž๋‹ฟ์€ ํ™˜๊ฒฝ์—์„œ C-S-H(calcium silicate hydrates)์˜ ์นผ์Š˜ ์„ฑ๋ถ„์„ ํƒˆ๋ฝ์‹œํ‚ค๊ณ  M-S-H๋ฅผ ํ˜•์„ฑํ•œ๋‹ค. ์ด ํƒˆ์นผ์Š˜ํ™”(decalcification)๋Š” ๋ณดํ†ต 1๊ฐœ์›” ์ด๋‚ด์— ์‹œ์ž‘๋˜๋ฉฐ 1๋…„์ด ์ง€๋‚˜๋ฉด ๋Œ€๋ถ€๋ถ„์˜ C-S-H๊ฐ€ M-S-H๋กœ ๋ฐ”๋€Œ๊ฒŒ ๋˜๋Š”๋ฐ, ์ด๋•Œ ์ƒ์„ฑ๋œ M-S-H ์ƒ์˜ Mg/Si ๋น„์œจ์€ 0.8-1.3์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค(Bernard et al. 2017(2), 2018(1)). ๋ฌธํ—Œ์€ ํ•ฉ์„ฑํ•œ ๋ฌผ์งˆ์— ๋Œ€ํ•œ ์—ฐ๊ตฌ์˜€๊ธฐ ๋•Œ๋ฌธ์— ์œ ๊ธฐ์ฒด๋กœ ์กด์žฌํ•˜๋Š” ์‹œ๋ฉ˜ํŠธ ํŽ˜์ด์ŠคํŠธ ๋‚ด ํ™˜๊ฒฝ์„ ๊ณ ๋ คํ•˜๋ฉด Ca ๊ณ„์—ด ์ˆ˜ํ™”๋ฌผ์ด ๋‹ค๋Ÿ‰ ์กด์žฌํ•˜๊ณ  SiO2๊ฐ€ ์ถฉ๋ถ„ํ•œ ํ™˜๊ฒฝ์—์„œ๋Š” ๋งค์šฐ ๋Š๋ฆฐ ๋ฐ˜์‘์ด์ง€๋งŒ M-S-H๊ฐ€ ๊ณ„์†ํ•ด์„œ ์ƒ์„ฑ๋  ์ˆ˜ ์žˆ์Œ์„ ์‹œ์‚ฌํ•œ๋‹ค. M-S-H๋Š” ๋‹ค์Œ ์‹(2)์˜ ์ˆ˜ํ™”๋ฐ˜์‘์„ ํ†ตํ•ด ์ƒ์„ฑ๋œ๋‹ค.

Fig. 4. XRD curve of FNS raw material (F: Fe2SiO4, M: Mg2SiO4)

../../Resources/kci/JKCI.2019.31.2.181/fig4.png

(2)

$Mg_{2}Si O_{4}+ H_{2}Oโ†’MยญSยญH$

$\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quadโ†’ Mg(OH)_{2}+ M ยญS ยญH$

์ดˆ๊ธฐ ์žฌ๋ น์ธ 7์ผ ์ฐจ์— ์ธก์ •๋œ ๊ฒฝํ™”๋œ FNS ํŽ˜์ด์ŠคํŠธ์˜ XRD ์ปค๋ธŒ๋ฅผ Fig. 5, ์žฅ๊ธฐ ์žฌ๋ น์ธ 1๋…„ ์ฐจ์— ์ธก์ •ํ•œ ๊ฒƒ์€ Fig. 6์— ๋‚˜ํƒ€๋‚ด์—ˆ๊ณ , ๋ฌผ์งˆ์˜ ์ฃผ์š” ํ”ผํฌ๋ฅผ Table 3์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ๋ฌธํ—Œ์— ๋”ฐ๋ฅด๋ฉด MgO๋ฅผ ํฌํ•จํ•˜๊ณ  ์žˆ๋Š” ํŽ˜์ด์ŠคํŠธ์˜ ์ˆ˜ํ™”๋ฌผ์—๋Š” hydrotalcite, K-struvite, Mg(OH)2, M-S-H ๋“ฑ์ด ๋‚˜ํƒ€๋‚œ๋‹ค๊ณ  ํ•˜๋‚˜(Hong et al. 2013(5)), ๋ณธ ์—ฐ๊ตฌ์—์„œ ์ˆ˜ํ–‰๋œ XRD ์‹œํ—˜์—์„œ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์€ ๊ฒฐ๊ณผ๊ฐ€ ๋‚˜ํƒ€๋‚ฌ๋‹ค. OPC์™€ FNS์— ์ˆ˜ํ™”๋ฌผ ํ˜•ํƒœ๊ฐ€ ๊ณตํ†ต์œผ๋กœ ๋‚˜ํƒ€๋‚œ ๊ฒƒ์€ Ca(OH)2 (์ดํ•˜ CH), C-S-H, Ca6(Al(OH)6)2 (SO4)3(H2O)26) (ettringite)์˜€์œผ๋ฉฐ, ๋ฏธ์ˆ˜ํ™”๋ฌผํ˜•ํƒœ๊ฐ€ ๋‚˜ํƒ€๋‚œ ๊ฒƒ์—๋Š” CaSO4 (gypsum),Ca3SiO5 (์ดํ•˜ C3S)๊ฐ€ ์žˆ์—ˆ๋‹ค. FNS์—๋งŒ ์กด์žฌํ•˜๋Š” ๋ฌผ์งˆ์€ ๋ฏธ์ˆ˜ํ™”๋ฌผ์ธ forsterite (Mg2SiO4)์™€ forsterite์— OH๊ฐ€ ๋ถ™์–ด ์ƒ์„ฑ๋œ M-S-H ์ˆ˜ํ™”๋ฌผ์ด ๋ฐœ๊ฒฌ๋˜์—ˆ๋‹ค. XRD ์ปค๋ธŒ์—์„œ๋Š” ๊ฐ„์„ญ์œผ๋กœ ์ธํ•ด Si, H, O๊ฐ€ ํฌํ•จ๋˜์–ด ์žˆ๋Š” ์—ฌ๋Ÿฌ ๋ฌผ์งˆ์˜ ํ”ผํฌ๊ฐ€ ์ค‘์ฒฉ๋˜๊ณค ํ•˜๋Š”๋ฐ(Durdziล„ski et al. 2017(4)), forsterite์™€ M-S-H, C3S์˜ ํšŒ์ ˆ ํŒจํ„ด์ด ์œ ์‚ฌํ•˜์—ฌ ์ค‘์ฒฉ๋˜์–ด ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ 7์ผ ์–‘์ƒ ์‹œํŽธ์—์„œ๋Š” M-S-H๊ฐ€ ๋‚˜ํƒ€๋‚ด๋Š” ํ”ผํฌ์˜ ์„ธ๊ธฐ๊ฐ€ ๋งค์šฐ ๋‚ฎ์•„ ๊ฑฐ์˜ ๋‚˜ํƒ€๋‚˜์ง€ ์•Š์•˜๊ณ  1๋…„ ์–‘์ƒ ์‹œํŽธ์—์„œ๋Š” forsterite์™€ M-S-H์˜ ํ”ผํฌ๊ฐ€ ๋ชจ๋‘ ๋†’๊ฒŒ ์ค‘์ฒฉ๋˜์–ด ๋‚˜ํƒ€๋‚ฌ๋‹ค.

Fig. 5. XRD curves of FNS paste at 7 days curing

../../Resources/kci/JKCI.2019.31.2.181/fig5.png

Fig. 6. XRD curves of FNS paste at 1-year curing

../../Resources/kci/JKCI.2019.31.2.181/fig6.png

**Marks in Fig. 5, 6 indicate: โ˜…: Ca(OH)2 โ—†: Ca3SiO5 โ—: CaSO4 โ–ฒ: Mg2SiO4 โ–ณ: M-S-H โ– : C-S-H โ—‹: Ca6(Al(OH)6)2 (SO4)3(H2O)26)

Table 3. XRD peak list

Phase name

2ฮธ (degree)

Calcium Hydroxide

Ca(OH)2

18.02, 29.35, 34.08, 36.44, 47.13, 50.77, 54.35, 62.32

Hatrurite

Ca3SiO5

22.98, 29.35, 30.10, 32.23, 32.65, 34.43, 39.40, 41.33, 47.13, 49.94, 51.77, 56.61, 60.01, 62.32

Calcium Sulfate

CaSO4

22.98, 25.40, 27.10, 29.35, 32.65, 35.68, 36.44, 41.33, 43.86, 47.13, 50.77

Forsterite

Mg2SiO4

17.29, 22.98, 23.86, 25.40, 29.35, 32.23, 34.43, 35.68, 36.44, 39.40, 41.33, 43.86, 48.37, 50.77, 51.78, 56.61, 62.32

M-S-H

17.29, 22.98, 23.98, 32.23, 35.68, 36.44, 39.39, 51.78, 62.32

C-S-H

22.98, 32.23, 39.40, 52.17, 56.12, 61.89, 62.60

Ettringite

Ca6(Al(OH)6)2 (SO4)3(H2O)26)

9.06, 15.64, 18.88, 32.23, 41.33

์žฌ๋ น๊ณผ ์น˜ํ™˜์œจ์— ๋”ฐ๋ผ ์ฃผ์š” ํ”ผํฌ์ธ 17.29, 22.98, 35.6, 36.45ยฐ(2ฮธ)์—์„œ์˜ M-S-H์™€ forsterite, 18.02, 34.06ยฐ(2ฮธ)์—์„œ์˜ CH, 29.03ยฐ(2ฮธ)์—์„œ์˜ C3S์™€ gypsum์˜ CPS ์ฐจ์ด๊ฐ€ ๊ฐ€์žฅ ๋‘๋“œ๋Ÿฌ์ง€๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๋จผ์ € ์‹œ๋ฉ˜ํŠธ ๊ฒฝํ™”์ฒด์˜ ์ˆ˜ํ™” ์ฒ™๋„๋กœ ์‚ผ์„ ์ˆ˜ ์žˆ๋Š” CH์˜ ํ”ผํฌ๋Š” 7์ผ ์ฐจ์—์„œ FNS ์น˜ํ™˜์œจ๊ณผ ๊ด€๊ณ„์—†์ด๋‚ฎ์€ CPS๋ฅผ ๋ณด์˜€๋‹ค. 1๋…„ ์ฐจ์—์„œ๋Š” OPC ํ•จ๋Ÿ‰์ด ๋งŽ์„์ˆ˜๋ก CH์˜ ํ”ผํฌ๊ฐ€ ๋งค์šฐ ๋†’๊ฒŒ ์ธก์ •๋˜์—ˆ๋‹ค. FNS 50%์˜ ๊ฒฝ์šฐ๋Š” OPC์˜ CH ํ”ผํฌ๋ณด๋‹ค 1/4 ์ˆ˜์ค€์œผ๋กœ ๋‚ฎ๊ฒŒ ์ธก์ •๋˜์—ˆ๋‹ค. ๋ฏธ์ˆ˜ํ™”๋ฌผ์ธ C3S์™€ gypsum์€ 7์ผ์ฐจ ์‹œํŽธ์—์„œ๋Š” OPC ๋ฅผ ๋งŽ์ด ํ•จ์œ ํ• ์ˆ˜๋ก ๋†’์€ ํ”ผํฌ๋ฅผ ๋ณด์˜€๊ณ , 1๋…„ ์ฐจ์—์„œ๋„ ์น˜ํ™˜๋Ÿ‰์— ๋”ฐ๋ฅธ ๊ฒฝํ–ฅ์€ ๊ฐ™์ง€๋งŒ CH, C-S-H, ettringite ๋“ฑ์˜ ๋ฐ˜์‘๋ฌผ์„ ์ƒ์„ฑํ•จ์— ๋”ฐ๋ผ ์ „์ฒด์ ์ธ ํ”ผํฌ๋Š” 7์ผ ์ฐจ๋ณด๋‹ค FNS ํ•จ๋Ÿ‰์ด ๋งŽ์„์ˆ˜๋ก 7์ผ ์ฐจ์™€ 1๋…„์ฐจ ๋ชจ๋‘์—์„œ ๋†’์€ ํ”ผํฌ๋ฅผ ๋ณด์˜€๋‹ค. ์ด๋Š” forsterite์˜ ๋ฐ˜์‘์„ฑ์ด ๋‚ฎ์•„ ํ•จ์œ ๋Ÿ‰์ด ๋งŽ์œผ๋ฉด ์ˆ˜ํ™”๋ฐ˜์‘์— ์ฐธ์—ฌํ•œ ๋ฌผ์งˆ์ด ์ ์–ด์ง€๊ฒŒ ๋˜๊ธฐ ๋•Œ๋ฌธ์ด๋‹ค. Forsterite์™€ ๋Œ€๋ถ€๋ถ„์˜ ํ”ผํฌ๊ฐ€ ๋™์ผํ•˜๊ฒŒ ๋‚˜ํƒ€๋‚˜๋Š” M-S-H์˜ ๊ฒฝ์šฐ 1๋…„ ์ฐจ ์‹œํŽธ์—์„œ ๋‘๋“œ๋Ÿฌ์ง€๊ฒŒ ๋‚˜ํƒ€๋‚ฌ์œผ๋ฉฐ, ์ค‘์ฒฉ๋˜์ง€ ์•Š์€ ํ”ผํฌ๋ฅผ ๋ณด์•˜์„ ๋•Œ FNS 30% ์ด์ƒ ์น˜ํ™˜ํ•  ๊ฒฝ์šฐ์— ๋งŽ์ด ์ƒ์„ฑ๋œ ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. ๋ฌธํ—Œ์— ๋”ฐ๋ฅด๋ฉด, CH์™€ C-S-H๋Š” MgO ๊ณ„์—ด ๋ฐ˜์‘๋ฌผ์ด ์žˆ์„ ๋•Œ Mg(OH)2์™€ M-S-H (magnesium silicate hydrates) ๊ฒ”์„ ์ƒ์„ฑํ•œ๋‹ค(Sonat et al. 2018(18)). XRD์—์„œ๋Š” Mg(OH)2๊ฐ€ ๋‚˜ํƒ€๋‚˜์ง€ ์•Š์•˜๊ธฐ ๋•Œ๋ฌธ์— SEM ๋ถ„์„์— ๋Œ€ํ•˜์—ฌ ์ˆ˜ํ™”๊ฐ€ ๋˜์ง€ ์•Š์€ forsterite์™€ M-S-H์— ๋Œ€ํ•ด ์ง‘์ค‘์ ์œผ๋กœ ์ด๋ฏธ์ง€๋ฅผ ๋ถ„์„ํ•˜์˜€๋‹ค.

3.1.2 SEM๊ณผ EDX ๋ถ„์„

Forsterite๋Š” Si๋ฅผ ์ค‘์‹ฌ์œผ๋กœ Mg์™€ O๊ฐ€ 120ยฐ ๊ฐ๋„๋กœ ์ •์‚ฌ๋ฉด์ฒด ํ˜•ํƒœ์˜ ๊ฒฐํ•ฉ์„ ํ•˜๊ณ  ์žˆ๊ธฐ ๋•Œ๋ฌธ์— ๊ฒฐ์ •์€ ๊ฐ์ง„ ํ˜•ํƒœ๋ฅผ ํ•˜๊ณ  ์žˆ์œผ๋ฉฐ ์ˆ˜ํ™”๊ฐ€ ์ด๋ค„์ง€๋ฉด OH ์ด์˜จ์ด ๊ฒฐํ•ฉ ๋ ˆ์ด์–ด ์ธต ์‚ฌ์ด์— ๋ผ์–ด ํŒ์ƒํ˜•์ด ์—ฌ๋Ÿฌ ๊ฒน ๊ฒน์ณ์ง„ ํ˜•ํƒœ๋กœ ๋ณด์ธ๋‹ค(De Souza et al. 2013(3)). ๋”ฐ๋ผ์„œ SEM์„ ์‚ฌ์šฉํ•˜์—ฌ ์ด์™€ ๋น„์Šทํ•œ ํ˜•ํƒœ๋ฅผ ๋ค ๋ฌผ์งˆ์˜ ์ด๋ฏธ์ง€๋ฅผ ์–ป๊ณ , ํ•ด๋‹น ๋ฌผ์งˆ์— ๋Œ€ํ•˜์—ฌ EDX๋ฅผ ํ†ตํ•ด ์›์†Œ ๋ถ„์„์„ ์‹ค์‹œํ•˜์—ฌ ๋ฏธ์ˆ˜ํ™”๋ฌผ์„ ํ™•์ธํ•ด ๋ณด์•˜๋‹ค. FNS ์‹œํŽธ์—์„œ ๋‚˜ํƒ€๋‚  ์ˆ˜ ์žˆ๋Š” ๋ฏธ์ˆ˜ํ™”๋ฌผ์€ ๊ณตํ†ต๋˜๋ฏ€๋กœ FNS 30%์— ๋Œ€ํ•ด์„œ๋งŒ ๊ณ ๋ฐฐ์œจ ์ด๋ฏธ์ง€๋ฅผ ๋ถ„์„ํ•˜์˜€๋‹ค. Fig. 7์€ SEM ์ด๋ฏธ์ง€์—์„œ forsterite๋กœ ์ถ”์ •๋˜๋Š” ๋ฌผ์งˆ์— ๋Œ€ํ•ด EDX๋ฅผ ์ธก์ •ํ•˜์—ฌ ์•„๋ž˜์— ํ”ผํฌ๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค. ๋งจ ์™ผ์ชฝ์€ ์—ฌ๋Ÿฌ ๊ฒน์˜ ํŒ์ƒ์ด ๊ฒน์ณ์ง„ M-S-H์ด๋ฉฐ ๊ฐ€์šด๋ฐ ์ด๋ฏธ์ง€๋Š” C-S-H๊ฐ€ ์šด์ง‘ํ•ด ์žˆ๋Š” ๋ถ€๋ถ„์— ์กด์žฌํ•˜๋Š” M-S-H, ๋งจ ์˜ค๋ฅธ์ชฝ์˜ ๋ฌผ์งˆ์€ ๋ฐ˜์‘์„ ํ•˜์ง€ ์•Š์•„ ๊ฐ์ง„ ํ˜•ํƒœ๋ฅผ ์œ ์ง€ํ•˜๊ณ  ์žˆ๋Š” forsterite์ด๋‹ค. ํ•ด๋‹น ๋ฌผ์งˆ์— ๋Œ€ํ•ด EDX๋ฅผ ํ†ตํ•ด ์›์ž ์ค‘๋Ÿ‰ ํผ์„ผํŠธ๋ฅผ ์–ป์–ด Mg/Si ๋ชฐ๋ถ„์œจ์„ ๊ณ„์‚ฐํ•œ ๊ฒฐ๊ณผ ์™ผ์ชฝ๋ถ€ํ„ฐ ๊ฐ 0.78, 0.68, 0.97๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๊ทธ ๊ฐ’์ด 1๋ณด๋‹ค ์ž‘์„์ˆ˜๋ก Ca๊ฐ€ ํ•จ๊ป˜ ์–ฝํ˜€ ์žˆ๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ์œผ๋ฉฐ ์ด๋ฅผ ํ†ตํ•ด C-S-H์™€ M-S-H ์‚ฌ์ด์— 2๊ฐ€ ๊ธˆ์†์ด์˜จ์˜ ๊ตํ™˜์ด ์ผ์–ด๋‚  ์ˆ˜ ์žˆ์Œ๋„ ์ถ”์ •ํ•  ์ˆ˜ ์žˆ๋‹ค. ๋˜ํ•œ forsterite๊ฐ€ ๋ฐ˜์‘์„ ์•ˆ ํ• ์ˆ˜๋ก Mg/Si ๋ชฐ๋ถ„์œจ์ด 1์— ๊ฐ€๊นŒ์šด ๊ฐ’์ด ๋‚˜์˜ด์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ๋‹ค. Fig. 8(a)๋Š” FNS 30%์˜ ์žฌ๋ น 1๋…„์งธ์˜ ์ˆ˜ํ™”๋œ ๋ชจ์Šต์œผ๋กœ, M-S-H์™€ ๋ฏธ์ˆ˜ํ™” forsterite ๊ฐ€ C-S-H์— ๋‘˜๋Ÿฌ์‹ธ์—ฌ ์žˆ๋Š” ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. Pokrovsky and Schott (2000(15))์˜ ์—ฐ๊ตฌ์— ์˜ํ•˜๋ฉด ์ •์‚ฌ๋ฉด์ฒด๊ตฌ์กฐ์˜ forsterite๋Š” ์—ผ๊ธฐ์„ฑ ์šฉ๋งค ๋‚ด์—์„œMg2+ ์ด์˜จ์ด ๊ฐ€์ˆ˜๋ถ„ํ•ด๋œ๋‹ค. FNS๊ฐ€ ํ˜ผ์ž…๋œ ์‹œ๋ฉ˜ํŠธ ํŽ˜์ด์ŠคํŠธ์˜ ์ˆ˜ํ™” ๊ณผ์ •์—์„œ ๊ฐ€์ˆ˜๋ถ„ํ•ด๊ฐ€ ์ผ์–ด๋‚œMg2+ ์ด์˜จ์ด C-S-H์˜ Ca2+ ์ด์˜จ๊ณผ ์น˜ํ™˜๋˜์–ด M-S-H๊ฐ€ ์ƒ์„ฑ๋  ์ˆ˜ ์žˆ์Œ์„์ถ”์ •ํ•  ์ˆ˜ ์žˆ๋‹ค. ๊ทธ๋Ÿฌํ•œ ์ด์œ ๋กœ SEM ์ด๋ฏธ์ง€์—์„œ๋„ M-S-H๊ฐ€ C-S-H์— ๋‘˜๋Ÿฌ์‹ธ์—ฌ ์กด์žฌํ•˜๊ณ  ์žˆ์„ ๊ฒƒ์ด๋‹ค. ๊ฒฐ๊ณผ์ ์œผ๋กœ Ca2+ ์ด์˜จ์ด ์žˆ๋˜ ์ž๋ฆฌ์—Mg2+ ์ด์˜จ์ด ๊ฒฐํ•ฉํ•˜๊ฒŒ ๋˜๋ฉด์„œ ๊ฒฐํ•ฉ๊ธธ์ด๊ฐ€ ๋‹ฌ๋ผ์ง€๊ธฐ ๋•Œ๋ฌธ์— ํŽ˜์ด์ŠคํŠธ ๋ถ€๋ถ„์˜ ๋ฐ€๋„๊ฐ€ ๋†’์•„์ง€๊ณ  FNS ์ฝ˜ํฌ๋ฆฌํŠธ์˜ ์™ธ๋ถ€ ์ด์˜จ์— ๋Œ€ํ•œ ์นจํˆฌ ์ €ํ•ญ์„ฑ์ด ํ–ฅ์ƒ๋  ์ˆ˜ ์žˆ์„ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ Fig. 8(b)์˜ FNS 50%๋ฅผ ๋ณด๋ฉด 2000๋ฐฐ์œจ๋กœ ๋„“์€ ์˜์—ญ์„ ์ฐ์—ˆ์Œ์—๋„ FNS๋ฅผ ๋‹ค๋Ÿ‰ ์น˜ํ™˜ํ•˜์˜€์„ ๊ฒฝ์šฐ ์ˆ˜ํ™”๊ฐ€ ๊ฑฐ์˜ ๋˜์ง€ ์•Š์€ ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. ๋ฐ˜์‘ํ•˜์ง€ ๋ชปํ•œ forsterite ์ฃผ๋ณ€์ด C-S-H๋กœ ๋ฎ์—ฌ ์žˆ์„ ๋ฟ ๋‹ค๋ฅธ ์ˆ˜ํ™”๋ฌผ์€ ๊ฑฐ์˜ ๋ณด์ด์ง€ ์•Š๋Š”๋‹ค. ๋‹ค๋งŒ FNS ๋ฏธ์ˆ˜ํ™”๋ฌผ์ด ์กด์žฌํ•˜๋Š” ๊ณณ์—๋Š” ๊ณต๊ทน์ด ๊ฑฐ์˜ ๋ณด์ด์ง€ ์•Š๋Š”๋‹ค๋Š” ์ ์—์„œ ์น˜ํ™˜์œจ์ด ๋†’์€ ํŽ˜์ด์ŠคํŠธ ๋‚ด์˜ ๊ณต๊ทน์ด ์กฐ๋ฐ€ํ•  ์ˆ˜ ์žˆ์Œ์„ ์˜๋ฏธํ•œ๋‹ค.

Fig. 7. SEM image of Mg-based substance in FNS 30% paste at 1-year curing (different phase of forsterite-Mg2SiO4 and forsterite hydrous-Mg2SiO4(OH)0.5)

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Fig. 8. SEM image of M-S-H hydrates in 1-year cured paste of: (a) FNS 30% and (b) FNS 50%

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3.2 FNS ์น˜ํ™˜๋Ÿ‰์— ๋”ฐ๋ฅธ ์ดˆ๊ธฐ ๋ฐ ์ค‘์žฅ๊ธฐ ์ˆ˜ํ™”๋„

3.1์—์„œ FNS ํŽ˜์ด์ŠคํŠธ์˜ ์ˆ˜ํ™”์ƒ์„ฑ๋ฌผ๊ณผ ๋ฐ˜์‘์„ฑ์„ ์‚ดํŽด๋ณด์•˜๋‹ค๋ฉด, ๋ณธ ๋‹จ๋ฝ์—์„œ๋Š” FNS์˜ ์น˜ํ™˜๋Ÿ‰์— ๋”ฐ๋ฅธ ์ดˆ๊ธฐ ์ˆ˜ํ™” ํŠน์„ฑ์„ ์‘๊ฒฐ์‹œ๊ฐ„์„ ํ†ตํ•ด ์•Œ์•„๋ณด๊ณ , ์ค‘์žฅ๊ธฐ์ ์œผ๋กœ ์ƒ์„ฑ๋˜๋Š” ์ˆ˜ํ™”๋ฌผ์˜ ์–‘๊ณผ, ๊ณต๊ทน๋„๋Š” ์–ด๋–ป๊ฒŒ ๋‚˜ํƒ€๋‚˜๋Š”์ง€ BSE ๋ถ„์„์„ ํ†ตํ•ด ์•Œ์•„๋ณด์•˜๋‹ค.

๊ด€์ž…์ €ํ•ญ์นจ์„ ์ด์šฉํ•ด ์ €ํ•ญ ๊ฐ’์ด 3.5 MPa์ผ ๋•Œ์˜ ์‹œ๊ฐ„์„ ์ดˆ๊ฒฐ, 28 MPa์ผ ๋•Œ์˜ ์‹œ๊ฐ„์„ ์ข…๊ฒฐ์ด๋ผ๊ณ  ๋‘๊ณ  ์‹œํ—˜ํ•˜์˜€์„ ๋•Œ ๋‚˜ํƒ€๋‚œ OPC์™€ FNS ๋ชจ๋ฅดํƒ€๋ฅด์˜ ์‘๊ฒฐ์‹œ๊ฐ„ ์‹œํ—˜ ๊ฒฐ๊ณผ๋ฅผ Fig. 9์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์™ธ๊ธฐ ์˜จ๋„๊ฐ€ 20 ยฑ 2 ยฐC์˜€๊ธฐ ๋•Œ๋ฌธ์— ๋‹ค์†Œ ๋‚ฎ์€ ์˜จ๋„์—์„œ ๋ฐฐํ•ฉ์ด ๋˜์—ˆ์œผ๋ฉฐ ๋”ฐ๋ผ์„œ OPC์˜ ์ดˆ๊ฒฐ๊ณผ ์ข…๊ฒฐ์ด 360๋ถ„๊ณผ 537๋ถ„์œผ๋กœ ์„œ์ค‘ ๋ฐฐํ•ฉ์ผ ๋•Œ๋ณด๋‹ค๋Š” ๊ธธ๊ฒŒ ์ธก์ •๋˜์—ˆ๋‹ค. FNS ๋ชจ๋ฅดํƒ€๋ฅด์˜ ์ดˆ๊ธฐ ์ˆ˜ํ™”๋ฅผ ํ™•์ธํ•˜๊ธฐ ์œ„ํ•ด ์ดˆ๊ฒฐ๊ณผ ์ข…๊ฒฐ์„ ์ด์— ๋น„๊ตํ•ด ๋ณด์•˜์„ ๋•Œ, ์ดˆ๊ฒฐ์€ FNS ์น˜ํ™˜๋Ÿ‰์ด ๋งŽ์•„์งˆ์ˆ˜๋ก ์ตœ๋Œ€ 55๋ถ„๊นŒ์ง€ ์ˆ˜ํ™”๊ฐ€ ์ง€์—ฐ๋˜๋Š” ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ์—ˆ๋‹ค. ๋ฐ˜๋ฉด ์ข…๊ฒฐ์€ ์ „๋ฐ˜์ ์œผ๋กœ OPC์˜ ์ข…๊ฒฐ๊ณผ ํฐ ์ฐจ์ด๊ฐ€ ๋ฒŒ์–ด์ง€์ง€ ์•Š์•˜๋‹ค. 10%, 30% ์น˜ํ™˜์‹œ์—๋Š” 10๋ถ„ ๋‚ด์™ธ๋กœ ์ง€์—ฐ๋˜์—ˆ๊ณ , 50% ์น˜ํ™˜์‹œ์—๋Š” 30๋ถ„์ด ์ง€์—ฐ๋˜์—ˆ๋‹ค. ์‘๊ฒฐ์€ ์ดˆ๊ธฐ ์ˆ˜ํ™” ์‹œ ์ˆ˜ํ™”์—ด์— ๋ฏผ๊ฐํ•˜๊ฒŒ ์˜ํ–ฅ์„ ๋ฐ›๊ธฐ ๋•Œ๋ฌธ์— C2S, C3S ์–‘์ด ๊ธฐ์กด OPC ๋ฐฐํ•ฉ์— ๋น„ํ•ด ํ˜„์ €ํžˆ ๋‚ฎ์€ FNS์—์„œ๋Š” ์ดˆ๊ธฐ ๋ฐ˜์‘์„ฑ์ด ๋งค์šฐ ๋–จ์–ด์ง€๊ณ  ์ˆ˜ํ™”์—ด์ด ์ ๊ฒŒ ๋ฐœ์ƒํ•ด ์‘๊ฒฐ์ด ์ง€์—ฐ๋˜์—ˆ๋‹ค๊ณ  ์ƒ๊ฐํ•  ์ˆ˜ ์žˆ๋‹ค. ์ดˆ๊ธฐ๊ฐ•๋„๋ฅผ ๋†’๊ฒŒ ํ•„์š”๋กœ ํ•˜๋Š” ๊ตฌ์กฐ๋ฌผ์— ๋Œ€ํ•ด์„œ๋Š” ๋ณด๊ฐ• ๊ฐ€๋Šฅํ•œ ์ ์ ˆํ•œ ๋ฐฐํ•ฉ์„ ์ œ์‹œํ•ด์•ผ ํ•  ๊ฒƒ์œผ๋กœ ์ƒ๊ฐ๋œ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ๋ ˆ๋ฏธ์ฝ˜ ๋ฐฐํ•ฉ ์ž‘์—… ์‹œ ์ž‘์—… ์‹œ๊ฐ„์˜ ํ™•๋ณด ์ธก๋ฉด์—์„œ๋Š” FNS 10%์™€ 30%๋Š” OPC์— ๋น„ํ•ด ์ดˆ๊ฒฐ์€ 2-30๋ถ„ ์ง€์—ฐ๋˜๋‚˜ ์ข…๊ฒฐ์— ํฐ ์ฐจ์ด๊ฐ€ ์—†์–ด ์˜คํžˆ๋ ค ๋” ์œ ๋ฆฌํ•  ๊ฒƒ์œผ๋กœ ์ƒ๊ฐ๋˜๋ฉฐ, FNS 50%์˜ ๊ฒฝ์šฐ๋ผ๋„ ์ดˆ๊ฒฐ 415๋ถ„, ์ข…๊ฒฐ 567๋ถ„์€ ํšจ๊ณผ์ ์ธ ์‹œ๊ฐ„ ์šด์˜์ด ๊ฐ€๋Šฅํ•œ ๋ฒ”์œ„๋ผ๊ณ  ์ƒ๊ฐ๋œ๋‹ค.

Fig. 9. Setting time of FNS fresh mortar (Initial set: 3.5 MPa, final set: 28 MPa)

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์ค‘์žฅ๊ธฐ ์ˆ˜ํ™”์— ์žˆ์–ด์„œ๋Š” SEM-BSE ์ด๋ฏธ์ง€์˜ gray-scale ์ƒ‰์ƒ์˜์—ญ์„ ์ž„๊ณ„์  ์„ธ ๊ณณ์œผ๋กœ ๋‚˜๋ˆ„์–ด ๊ณ„์‚ฐ๋œ ๊ฒฐ์ •์งˆ ์ˆ˜ํ™”๋ฌผ๊ณผ ๊ฒ” ์ˆ˜ํ™”๋ฌผ ์˜์—ญ์˜ ํ•ฉ์„ ํ•ด๋‹น ๋ฌผ์งˆ์˜ ์ˆ˜ํ™”๋„๋กœ ๋ณด์•˜๋‹ค. ๊ฐ๊ธฐ ๋‹ค๋ฅธ ์ˆ˜ํ™”๋ฌผ์˜ ์ข…๋ฅ˜๋ฅผ ๊ตฌ๋ณ„ํ•  ์ˆ˜๋Š” ์—†์œผ๋‚˜ ์ˆ˜ํ™”๋ฌผ (๊ฒฐ์ •์งˆ๊ณผ ๊ฒ”์˜ ํ•ฉ)๊ณผ ๋ฏธ์ˆ˜ํ™”๋ฌผ, ๊ณต๊ทน์˜ ๊ตฌ๋ถ„์€ ๋ช…ํ™•ํžˆ ํ•  ์ˆ˜ ์žˆ๋‹ค๋Š” ์ ์—์„œ ์ˆ˜ํ™”๋„๋ฅผ ๋น„๊ต์  ์ •ํ™•ํžˆ ์˜ˆ์ธกํ•  ์ˆ˜ ์žˆ๋‹ค. OPC๋งŒ์„ ์‚ฌ์šฉํ–ˆ์„ ๋•Œ ๋‚˜ํƒ€๋‚˜๋Š” ์ˆ˜ํ™”๋ฌผ์ด ์•„๋‹Œ MgO ๊ณ„์—ด ์ˆ˜ํ™”๋ฌผ์ด ํฌํ•จ๋˜์–ด ์žˆ๋‹ค๊ณ  ํ•˜๋”๋ผ๋„ ํ•ด๋‹น ๋ฌผ์งˆ์ด ์กด์žฌํ•˜๋Š” ์œ„์น˜์—์„œ ๋‚˜ํƒ€๋‚ด๋Š” ์—๋„ˆ์ง€์˜ ์‚ฐ๋ž€ ์ •๋„๋Š” ๋น„์Šทํ•œ ์ˆ˜์ค€์ผ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋˜๋ฉฐ, ๋”ฐ๋ผ์„œ ์ƒ‰์ƒ ๋ฐœํ˜„๋„ ๊ฒฐ์ •์งˆ ์ˆ˜ํ™”๋ฌผ์˜ ํ•ด๋‹น ๋ฒ”์œ„ ๋‚ด์— ๋‚˜ํƒ€๋‚ฌ์„ ๊ฒƒ์œผ๋กœ ์ƒ๊ฐ๋œ๋‹ค.

Fig. 10์˜ ์ „๋ฐ˜์ ์ธ ๊ฒฝํ–ฅ์„ ์‚ดํŽด๋ณด์•˜์„ ๋•Œ, FNS์˜ ํ˜ผ์ž…๋Ÿ‰์ด ๋งŽ์•„์งˆ์ˆ˜๋ก ์ƒ์„ฑ๋œ ๊ฒฐ์ •์งˆ ์ˆ˜ํ™”๋ฌผ์˜ ์–‘์ด ๋งŽ์•„์ง€๊ณ  ๊ฒ” ์ˆ˜ํ™”๋ฌผ์˜ ์–‘์ด ๋‹ค์†Œ ์ค„์–ด๋“œ๋Š” ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ๋™์‹œ์— ๋ฏธ์ˆ˜ํ™”๋ฌผ์˜ ์–‘์ด ์ฆ๊ฐ€ํ•˜๊ณ  ๊ณต๊ทน์ด ์ค„์–ด๋“œ๋Š” ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. OPC๋งŒ ์‚ฌ์šฉํ•œ ํŽ˜์ด์ŠคํŠธ์˜ ๊ฒฝ์šฐ ๊ณต๊ทน์€ 12.43%๋กœ ๋‹ค์†Œ ๋†’๊ฒŒ ๋‚˜ํƒ€๋‚ฌ์ง€๋งŒ, ์ˆ˜ํ™”๋„๋Š” ์•ฝ 70%๋กœ ๋‚˜ํƒ€๋‚ฌ๊ณ  ๋ฏธ์ˆ˜ํ™”๋ฌผ์€ ์•ฝ 18%๋กœ ์ ๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๊ทธ์— ๋น„ํ•ด FNS๋Š” 60โˆผ66%์˜ ์ˆ˜ํ™”๋„๋ฅผ ๋ณด์˜€์œผ๋ฉฐ, ๋ฏธ์ˆ˜ํ™”๋ฌผ์€ ์น˜ํ™˜์œจ์ด ๋†’์„์ˆ˜๋ก ์ฆ๊ฐ€ํ•˜์—ฌ ์•ฝ 25โˆผ32%๊นŒ์ง€ ์ฆ๊ฐ€ํ•œ ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๊ณต๊ทน ์ธก๋ฉด์—์„œ๋Š” FNS๋ฅผ ๋งŽ์ด ํ˜ผ์ž…ํ• ์ˆ˜๋ก ์ ์€ ๊ณต๊ทน๋Ÿ‰์„ ๋ณด์˜€๋‹ค. FNS๋ฅผ 10%, 30%๋ฅผ ํ˜ผ์ž…ํ•œ ๊ฒฝ์šฐ๋ผ๋„ ๊ณต๊ทน์€ 7% ๋Œ€๋กœ ๋งค์šฐ ๋‚ฎ์•„์กŒ๊ณ  50%๊นŒ์ง€ ํ˜ผ์ž…ํ•˜๋ฉด 4.6%๊ฐ€๋Ÿ‰์œผ๋กœ ๋‚ฎ๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ์ด๋Š” FNS ๋ฏธ๋ถ„๋ง์˜ ๋ฐ˜์‘์†๋„๊ฐ€ OPC์— ๋น„ํ•ด ๋งค์šฐ ๋Šฆ๊ธฐ๋Š” ํ•˜๋‚˜ ์ž…์ž ์‚ฌ์ด์ฆˆ๊ฐ€ ์ž‘์•„ ์‹œ๋ฉ˜ํŠธ ๋งคํŠธ๋ฆญ์Šค ๋‚ด๋ฅผ ์กฐ๋ฐ€ํ•˜๊ฒŒ ๋งŒ๋“ค์–ด์ฃผ์–ด ๊ณต๊ทน๋ฅ ์„ ์ค„์ผ ์ˆ˜ ์žˆ๋Š” ์—ญํ• ์„ ํ•˜๋Š” ๊ฒƒ์ž„์„ ๋ช…๋ฃŒํ•˜๊ฒŒ ๋ณด์—ฌ์ค€๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ์ค‘์žฅ๊ธฐ ์ˆ˜ํ™”๋„๊ฐ€ FNS๋ฅผ ๋‹ค๋Ÿ‰ ํ˜ผ์ž…ํ•  ๊ฒฝ์šฐ ๋งค์šฐ ๋‚ฎ์•„์ง„๋‹ค๋Š” ์ ์—์„œ ๊ฐ•๋„ ๋ฐœํ˜„์˜ ์ธก๋ฉด์—์„œ๋Š” FNS๋ฅผ 30% ์ด์ƒ์œผ๋กœ ๋‹ค๋Ÿ‰ ์‚ฌ์šฉํ•  ๊ฒฝ์šฐ ๋ถ€์ •์ ์ด๋ฉฐ, ๋ฏธ์ˆ˜ํ™”๋ฌผ์ด ๊ณจ๊ณ ๋ฃจ ํŽผ์ณ์ง„ ์ƒํƒœ์—์„œ๋Š” ๋ฐ•๋ฆฌ๋‚˜ ์Šค์ผ€์ผ๋ง ๋“ฑ์˜ ์—ดํ™” ํ˜„์ƒ์ด ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ์„ ๊ฒƒ์œผ๋กœ ์ƒ๊ฐ๋œ๋‹ค.

Fig. 10. Hydration degree and porosity of FNS at 28 days using 30 frame of mapped BSE images with replacement ratios of 0% (OPC), 10%, 30% and 50%

../../Resources/kci/JKCI.2019.31.2.181/fig10.png

3.3 FNS ์น˜ํ™˜๋Ÿ‰์— ๋”ฐ๋ฅธ ๋ฏธ์„ธ๊ณต๊ทน๋ถ„ํฌ ํŠน์„ฑ

FNS์˜ ์น˜ํ™˜๋Ÿ‰์— ๋”ฐ๋ฅธ ๋ฏธ์„ธ๊ณต๊ทน์˜ ๋ถ„ํฌ์™€ ์ด ๊ณต๊ทน๋Ÿ‰(์ˆ˜์€์ด ์••์ž…๋œ ์ด๋Ÿ‰)์„ Fig. 11์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. dc๋กœ ํ‘œ๊ธฐ๋œ ๊ณต๊ทน์˜ ํฌ๊ธฐ๋Š” ์ž„๊ณ„๊ณต๊ทน๋ฐ˜์ง€๋ฆ„์œผ๋กœ, ์ˆ˜์€์ด ์ €์••์—์„œ ๊ณ ์••์œผ๋กœ ๊ณต๊ทน์˜ ํฌ๊ธฐ ๋ณ„๋กœ ๊ด€์ž…๋จ์— ๋”ฐ๋ผ ๋ถ„ํฌ๋ฅผ ๋‚˜ํƒ€๋‚ผ ๋•Œ ๋งคํฌ๋กœํฌ์–ด๊ฐ€ ์•„๋‹Œ ์˜์—ญ์—์„œ ๊ฐ€์žฅ ๊ธ‰๊ฒฉํ•˜๊ฒŒ ๊ด€์ž…๋Ÿ‰์ด ๋งŽ์•„์ง€๋Š” ๋•Œ์˜ ๊ณต๊ทน ํฌ๊ธฐ๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค. dc๊ฐ€ ์ž‘์„์ˆ˜๋ก ํŽ˜์ด์ŠคํŠธ๋ฅผ ๊ตฌ์„ฑํ•˜๊ณ  ์žˆ๋Š” ์ฃผ๋œ ๊ณต๊ทน์˜ ํฌ๊ธฐ๊ฐ€ ์ž‘์€ ๊ฒƒ์œผ๋กœ ๋ณผ ์ˆ˜ ์žˆ๊ณ , ๊ณต๊ทน์ด ์กฐ๋ฐ€ํ•˜๊ฒŒ ๊ตฌ์„ฑ๋˜์–ด ์žˆ๋‹ค๊ณ  ์ƒ๊ฐํ•  ์ˆ˜ ์žˆ๋‹ค. Fig. 11์„ ๋ณด๋ฉด OPC์˜ ๊ฒฝ์šฐ์—๋Š” dc ๊ฐ’์ด 0.835 ยตm๋กœ, ํฐ ๋ชจ์„ธ๊ด€ ์˜์—ญ์— ๊ณต๊ทน๋Ÿ‰์ด ์ง‘์ค‘๋˜์–ด ์žˆ๊ณ , ์ž‘์€ ๋ชจ์„ธ๊ด€๊ณผ ๊ฒ”๊นŒ์ง€ ๋„“์€ ๋ฒ”์œ„๋กœ ๋ถ„ํฌ๋˜์–ด ์žˆ์–ด ์ด ๊ณต๊ทน๋Ÿ‰์€ 0.188 mL/g์œผ๋กœ ๋†’๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๋ฐ˜๋ฉด FNS๋ฅผ ํ˜ผ์ž…ํ•œ ๊ฒฝ์šฐ์—๋Š” dc ๊ฐ’์ด ๋ชจ๋‘ ์ž‘์€ ๋ชจ์„ธ๊ด€ ์˜์—ญ์— ์†ํ•ด ์žˆ๊ณ , ์น˜ํ™˜๋Ÿ‰์ด ๋งŽ์•„์งˆ์ˆ˜๋ก ๊ทธ ์ˆ˜์น˜๊ฐ€ ๋งค์šฐ ์ž‘๊ฒŒ ๋‚˜ํƒ€๋‚œ ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. FNS 10%, 30%, 50%์˜ dc๊ฐ’์€ ๊ฐ๊ฐ0.433 ยตm, 0.088 ยตm, 0.062 ยตm ์ˆœ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๋ถ„ํฌ๋ฅผ ๋ณด๋ฉด FNS ํŽ˜์ด์ŠคํŠธ๋Š” ๊ณต๊ทน ๋Œ€๋ถ€๋ถ„์ด ์ž‘์€ ๋ชจ์„ธ๊ด€ ์˜์—ญ์— ๋ถ„ํฌํ•ด ์žˆ์Œ์„ ์•Œ ์ˆ˜ ์žˆ๊ณ , ์น˜ํ™˜๋Ÿ‰์ด ๋งŽ์•„์งˆ์ˆ˜๋ก ๊ณต๊ทน์ด ๋ถ„ํฌํ•˜๊ณ  ์žˆ๋Š” ํ‰๊ท ์ ์ธ ํฌ๊ธฐ๊ฐ€ ์ž‘์€ ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. ๋ฐ˜๋ฉด ๊ฒ” ์˜์—ญ์€ ์˜คํžˆ๋ ค OPC๋ณด๋‹ค๋„ ์ ๊ฒŒ ํฌํ•จํ•˜๊ณ  ์žˆ์Œ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. ์ด ๊ณต๊ทน๋Ÿ‰์€ FNS 10%์˜ ๊ฒฝ์šฐ 0.174 mL/g์œผ๋กœ OPC์˜ ์ด ๊ณต๊ทน๋Ÿ‰๋ณด๋‹ค ๋งŽ์ด ๊ฐ์†Œํ•˜์ง€ ์•Š์•˜์ง€๋งŒ, FNS 30%์˜ ๊ฒฝ์šฐ 0.140 mL/g์œผ๋กœ OPC๋ณด๋‹ค ์•ฝ 25% ๊ฐ์†Œํ•œ ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋‹ค. FNS 50%๋Š” ํ˜ผํ™”์žฌ์˜ ์ ˆ๋ฐ˜์ด FNS๋กœ ์น˜ํ™˜๋œ ๊ฒƒ์ด๊ธฐ ๋•Œ๋ฌธ์— ๊ธ‰๊ฒฉํ•œ ์ฐจ์ด๊ฐ€ ๋‚˜ํƒ€๋‚˜๋Š”๋ฐ, dc๊ฐ’๋„ ๋งค์šฐ ์ž‘๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๊ณ , ์ด ๊ณต๊ทน๋Ÿ‰์€ 0.104 mL/g์œผ๋กœ ์•ฝ 45%๊ฐ€ ์ค„์–ด๋“  ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. ๋ณธ ์—ฐ๊ตฌ์˜ 3.2 BSE ์ด๋ฏธ์ง€ ๋ถ„์„์—์„œ๋„ ์น˜ํ™˜๋Ÿ‰์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ๊ณต๊ทน๋„๊ฐ€ ๋งค์šฐ ์ค„์–ด๋“  ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ์—ˆ๋Š”๋ฐ, ์ด๋Š” ์ด๋ฏธ์ง€๋ฅผ 2์ฐจ์›์ ์œผ๋กœ ํ•ด์„ํ•œ ๊ฒƒ์ด๊ธฐ ๋•Œ๋ฌธ์— ๊ทธ ์ ˆ๋Œ€์ ์ธ ์–‘์˜ ๋น„๊ต๋งŒ์œผ๋กœ ๊ณต๊ทน์˜ ๋ถ„ํฌ๋ฅผ ์•Œ ์ˆ˜ ์—†์—ˆ์œผ๋‚˜, MIP ๋ถ„์„์„ ํ†ตํ•ด์„œ ๋ถ€ํ”ผ์— ๋Œ€ํ•œ 3์ฐจ์›์ ์ธ ๋ถ„์„์„ ํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค. MIP ๋ถ„์„์„ ํ†ตํ•ด FNS๋ฅผ ํ˜ผ์ž…ํ•  ๊ฒฝ์šฐ ๊ณต๊ทน ์‚ฌ์ด๋ฅผ ๋ฉ”์›Œ์ฃผ๋Š” ์—ญํ• ์„ ํ•˜์—ฌ ๋ชจ์„ธ๊ด€ ์˜์—ญ ์ค‘์—์„œ๋„ ์ž‘์€ ๋ชจ์„ธ๊ด€ ์˜์—ญ์œผ๋กœ ๊ณต๊ทน์˜ ํฌ๊ธฐ๋ฅผ ์ค„์—ฌ์ค„ ์ˆ˜ ์žˆ์Œ์ด ํ™•์ธ๋˜์—ˆ๋‹ค. ์ด๋Š” FNS์˜ ๋ถ„๋ง๋„๊ฐ€ 4,600 cm2/g์œผ๋กœ OPC๋ณด๋‹ค ํฌ๊ณ , ์ž…์ž์˜ ํฌ๊ธฐ ์ž์ฒด๋„ ์•ฝ 1.8๋ฐฐ ์ž‘๊ธฐ ๋•Œ๋ฌธ์— ๋‚˜ํƒ€๋‚  ์ˆ˜ ์žˆ๋Š” ํŠน์„ฑ์ด๋‹ค. ๋ณดํ†ต ์ถฉ์ „์žฌ ์—ญํ• ๋กœ ์‚ฌ์šฉํ•˜๋Š” ์‹ค๋ฆฌ์นด ํ„์˜ ๊ฒฝ์šฐ ์ด๋ณด๋‹ค ์ ๊ฒŒ๋Š” 2.5๋ฐฐ์—์„œ ๋งŽ๊ฒŒ๋Š” 10๋ฐฐ๊นŒ์ง€ ๋†’์€ ๋ถ„๋ง๋„์ž„์„ ์ƒ๊ฐํ•˜๋ฉด, ๋ถ„์‡„๋ฅผ ์œ„ํ•ด ํ•„์š”ํ•œ ๋น„์šฉ์„ ์•„๋‚„ ์ˆ˜ ์žˆ๋Š” ์žฅ์ ์ด ๋งค์šฐ ๋›ฐ์–ด๋‚œ ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ FNS ํŽ˜์ด์ŠคํŠธ ๋‚ด์—์„œ forsterite๊ฐ€ ๊ฑฐ์˜ ๋ฐ˜์‘ํ•˜์ง€ ์•Š๊ณ  ๋ฏธ์ˆ˜ํ™”๋ฌผ๋กœ ์กด์žฌํ•˜๊ธฐ ๋•Œ๋ฌธ์— ๊ณต๊ทน์€ ์ฑ„์›Œ์กŒ์„์ง€๋ผ๋„ ๋ฐ˜์‘ํ•˜์ง€ ์•Š์€ ๋ฏธ์ˆ˜ํ™”๋ฌผ์˜ ๊ฐ•๋„๊ฐ€ ์ˆ˜ํ™”๋ฌผ์— ๋น„ํ•ด ํ˜„์ €ํžˆ ๋‚ฎ์•„ ๊ตฌ์กฐ์ฒด์˜ ๊ฐ•๋„ ๋ฐœํ˜„์— ๋ถ€์ •์ ์ธ ์˜ํ–ฅ์„ ๋ผ์นœ๋‹ค. ๋”ฐ๋ผ์„œ ์ถฉ์ „์žฌ ์—ญํ• ์„ ํ•  ์ •๋„๋กœ๋งŒ 10โˆผ20% ์น˜ํ™˜ ๋ฐฐํ•ฉ์„ ์„ค๊ณ„ํ•˜์—ฌ ์‚ฌ์šฉํ•˜๋Š” ๊ฒƒ์ด FNS๋ฅผ ํ˜ผํ™”์žฌ๋กœ์„œ ํšจ๊ณผ์ ์œผ๋กœ ์‚ฌ์šฉํ•  ์ˆ˜ ์žˆ๋Š” ๋ฐฉ์•ˆ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

Fig. 11. Pore size distribution and total pore volume of FNS at 28 day of curing using MIP analysis: (a) OPC, (b) 10%, (c) 30%, and (d) 50%

../../Resources/kci/JKCI.2019.31.2.181/fig11.png

4. ๊ฒฐ ๋ก 

๋ณธ ์—ฐ๊ตฌ๋Š” ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ(FNS)์˜ ํŽ˜์ด์ŠคํŠธ ์ˆ˜ํ™”ํŠน์„ฑ๊ณผ ๊ณต๊ทน๋ถ„ํฌ๋ฅผ ๋ถ„์„ํ•˜์—ฌ ๊ธฐ์กด ์—ฐ๊ตฌ์—์„œ์˜ ๋ฌผ์„ฑ ๋ฐœํ˜„์ด ๊ฐ€๋Šฅํ•œ ์›์ธ์„ ๊ทœ๋ช…ํ•˜๊ณ ์ž ์ˆ˜ํ–‰๋˜์—ˆ์œผ๋ฉฐ, ํŽ˜๋กœ๋‹ˆ์ผˆ ์Šฌ๋ž˜๊ทธ์˜ ์น˜ํ™˜์œจ์„ โ€˜10%, 30%, 50%โ€™ 3๋‹จ๊ณ„๋กœ ๋‘๊ณ  XRD, SEM, EDX MIP ๋ถ„์„์„ ์‹ค์‹œํ•˜์—ฌ OPC์™€ ๋น„๊ตํ•˜์˜€๋‹ค. ์ด๋ฅผ ํ†ตํ•ด ์–ป์€ ๊ฒฐ๋ก ์€ ๋‹ค์Œ๊ณผ ๊ฐ™๋‹ค.

1) XRD ๋ถ„์„ ๊ฒฐ๊ณผ FNS ์›๋ฃŒ๋ฅผ ๊ตฌ์„ฑํ•˜๋Š” ์ฃผ์š” ๋ฌผ์งˆ์€ forsterite(Mg2SiO4)๊ณผ iron silicate(Fe2SiO4)์ธ ๊ฒƒ์œผ๋กœ ๋ฐํ˜€์กŒ์œผ๋ฉฐ, ๊ฐ 93%, 6%๋ฅผ ์ฐจ์ง€ํ•œ๋‹ค.

2) FNS ์ˆ˜ํ™”๋ฌผ์˜ ์žฅ๊ธฐ์žฌ๋ น XRD์—์„œ๋Š” ์น˜ํ™˜๋Ÿ‰์ด ๋งŽ์„์ˆ˜๋ก CH ์–‘์ด ์ ๊ฒŒ ๋‚˜ํƒ€๋‚ฌ์œผ๋ฉฐ, ๋ฐ˜๋Œ€๋กœ M-S-H์™€ ๋ฐ˜์‘ํ•˜์ง€ ์•Š์€ forsterite๋Š” ๋” ๋งŽ์ด ์กด์žฌํ–ˆ๋‹ค.

3) Forsterite๋Š” ๋Š๋ฆฐ ๋ฐ˜์‘์ด์ง€๋งŒ ์—ผ๊ธฐ์„ฑ ํ™˜๊ฒฝ์—์„œ C-S-H์™€ ๋ฐ˜์‘ํ•˜์—ฌ Ca2+ ์ด์˜จ์ด ์žˆ๋˜ ์ž๋ฆฌ์—Mg2+์ด์˜จ์ด ์น˜ํ™˜๋œ M-S-H๋ฅผ ํ˜•์„ฑํ•œ๋‹ค. ์ด ๋ฐ˜์‘์—๋Š” 1๋…„ ์ด์ƒ ์†Œ์š”๋œ๋‹ค.

4) BSE ์ด๋ฏธ์ง€ ๋ถ„์„์„ ํ†ตํ•ด FNS์˜ ์น˜ํ™˜์œจ์ด ๋†’์„์ˆ˜๋ก ์ˆ˜ํ™”๋„๊ฐ€ ํ˜„์ €ํžˆ ๋–จ์–ด์ง์„ ํ™•์ธํ•˜์˜€๋‹ค. OPC์˜ ๋ฏธ์ˆ˜ํ™”๋ฌผ์ด ์•ฝ 18%์ธ ๊ฒƒ์— ๋น„ํ•ด, FNS 30%, 50%๋Š” ๋ฏธ์ˆ˜ํ™”๋ฌผ์–‘์ด 30% ์ด์ƒ์ธ ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค.

5) MIP ๋ถ„์„์—์„œ OPC๋Š” ์ž„๊ณ„๊ณต๊ทน๋ฐ˜์ง€๋ฆ„์ด 0.835 ยตm๋กœ ํฐ ๋ชจ์„ธ๊ด€ ์˜์—ญ๋ถ€ํ„ฐ ๊ณต๊ทน์ด ๋ถ„ํฌ๋˜์–ด ์žˆ๋Š”๋ฐ, FNS์˜ ๊ฒฝ์šฐ FNS 10%, 30%, 50% ๊ฐ๊ฐ 0.433, 0.088, 0.062 ยตm๋กœ, ๋ชจ๋‘ ์ž‘์€ ๋ชจ์„ธ๊ด€ ์˜์—ญ๋ถ€ํ„ฐ ๊ณต๊ทน์ด ๋ถ„ํฌ๋˜์–ด ์žˆ๊ณ  ๊ณต๊ทน์˜ ์ด๋Ÿ‰๋„ FNS ํ˜ผ์ž…๋Ÿ‰์ด ๋งŽ์„์ˆ˜๋ก ๋” ์ ๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค.

6) Forsterite์˜ ๋Š๋ฆฐ ๋ฐ˜์‘์„ฑ์œผ๋กœ ์ธํ•ด FNS์˜ ์ดˆ๊ธฐ ์ˆ˜ํ™”๋„๊ฐ€ OPC๋ณด๋‹ค ๋” ๋‚ฎ๊ฒŒ ๋‚˜ํƒ€๋‚ฌ์„ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋˜๋ฉฐ ๊ธฐ์กด ์—ฐ๊ตฌ์—์„œ FNS๋ฅผ ๋‹ค๋Ÿ‰ ์‚ฌ์šฉํ•˜์˜€์„ ๊ฒฝ์šฐ ๊ฐ•๋„๊ฐ€ ๋‚ฎ๊ฒŒ ์ธก์ •๋œ ์ฃผ์š” ์›์ธ ์ค‘ ํ•˜๋‚˜๋กœ ์ถ”์ธกํ•  ์ˆ˜ ์žˆ๋‹ค.

7) FNS์˜ ๋†’์€ ๋ถ„๋ง๋„๋กœ ์ธํ•˜์—ฌ ์น˜ํ™˜์„ ๋งŽ์ด ํ•  ์ˆ˜๋ก ํŽ˜์ด์ŠคํŠธ ๋‚ด์˜ ๊ณต๊ทน์„ ๋งค์›Œ์ฃผ๋Š” ์ถฉ์ „ํšจ๊ณผ๊ฐ€ ๋‚˜ํƒ€๋‚˜ ์—ผํ™”๋ฌผ ๋“ฑ ์™ธ๋ถ€์ด์˜จ์˜ ์นจํˆฌ๊ฐ€ ๋‚ฎ๊ฒŒ ๋‚˜ํƒ€๋‚  ์ˆ˜ ์žˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ๊ณต๊ทน์ด ์ ์–ด๋„ FNS ์‹œ๋ฉ˜ํŠธ ๋งคํŠธ๋ฆญ์Šค๋ฅผ ๊ตฌ์„ฑํ•˜๊ณ  ์žˆ๋Š” ๋ฌผ์งˆ์ด ๋ฏธ์ˆ˜ํ™”๋ฌผ์ด๊ธฐ ๋•Œ๋ฌธ์— ๊ฐ•๋„ ๋ฐœํ˜„์—๋Š” ๋ถ€์ •์ ์ผ ์ˆ˜ ์žˆ๋‹ค.

๊ฐ์‚ฌ์˜ ๊ธ€

๋ณธ ์—ฐ๊ตฌ๋Š” ๊ตญํ† ๊ตํ†ต๋ถ€ ๊ตญํ† ๊ตํ†ต๊ธฐ์ˆ ์ด‰์ง„ ์—ฐ๊ตฌ๊ฐœ๋ฐœ์‚ฌ์—…์˜ ์—ฐ๊ตฌ๋น„์ง€์›(18CTAP-C132998-02)์— ์˜ํ•ด ์ˆ˜ํ–‰๋˜์—ˆ์Šต๋‹ˆ๋‹ค.

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