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1 Jurnal f the Krean Ceramic Sciety Vl. 44, N. 9, pp. 502~509, Examinatin n Applicatin f High-Perfrmance Cncrete using Fine Fly Ash as Replacement Material f Silica Fume Bum-Sik Lee, Sang-Kyu Kim, Sang-Yun Kim, Sun-Mi Chi, and Gun-Su Lee Husing & Urban Research Institute, Krea Natinal Husing Crp., Sengnam , Krea (Received August 18, 2007; Accepted September 12, 2007) š gj p e { š v m Á½ ³ Á½ Á Á w kœ k ( ; ) ABSTRACT This paper investigated hw Fine Fly Ash (FFA) with 14,000 cm 2 /g f Fineness affects the micr structure and material prperties f High-Perfrmance Cncrete (HPC) befre and after hardening frm Material Test f HPC and Cement Paste. FFA is applied as a substitute f Silica Fume which is used necessarily in prducing HPC. As a Material Test results, 5% FFA series specimen shws the lwer fluidity than SF series specimen. When, hwever, the Fluidity f 10% FFA series specimen is increased reversely t the similar value f SF series specimen. The Prsity f FFA series specimen f day age is displayed t 21~24%, which is higher than 19~20% prsity f SF series specimen, while that f day age is reached t 8~ 9%, which is imprved cmpared with 10% f SF series specimen. It can be thught that FFA has better influence n the prsity f HPC in case f lng term age. The Cmpressive strength f FFA series specimen shws the similar result with the prperty f prsity. The cmpressive strength f day age FFA series specimen is 98~ 106% f SF series specimen and 107% f plain specimen t reveal better strength develpment. Key wrds : High-Perfrmance Cncrete, Fine Fly Ash, Silica Fume, Prsity 1. 19» gj pƒ z g j p t ƒ,» gj p wš w» z» k š gj p w šd, x p y š. šd š š gj p w w yy ƒ š g j p j» w e { v š. ù e { yy w šƒ yy š gj p w œ ƒ, š gj p w wš š gj p z Crrespnding authr : Sang-Kyu Kim skkim@jugng.c.kr Tel : Fax : w w q. š gj p v wš šƒ e { w yy, y wš w y ey gj p ƒ» v ƒœw š v ( 14,000 cm 2 /g) w. š š gj p e { š v y v w» œw» w š v sww w [ p, FA(, š ), BS] w r p gj p w š v ƒ š gj p y z e w sƒw. 2. x z 2.1. x z š gj p š e { š v sƒ w» w š v ƒ ƒ 5%, 10% 502

2 š gj p e { š v m 50 Table 1. Design f Experiment Mix plan (wt %) Factr Levels * OPC BS FA SF FFA W/B(%) OPC Plain SF Admixture SF FFA FFA õ BS:blastfurnaceslag, FA:Flyash, SF:Silicafume, FFA:Fineflyash (blaine 14,000 cm 2 /g) Cncrete Cement paste Testing items Air cntents Fluidity(Slump-flw) Cmpressive strength Hydratin materials(xrd) Hydratin degree(dt-tga) Prsity structure(mip) Micr structure(sem) Micr hydratin heat(tcc) Table 2. The Chemical Cmpnent f Materials (wt %) Blaine (cm 2 /g) SiO 2 Al 2 O Fe 2 O CaO MgO SO Na 2 O K 2 O TiO 2 Ig.lss OPC, BS 4, FA, SF 200, FFA 14, x z w, e { 5%, 10% w x OPC x (OPC, BS, FA) x z w ƒƒ w r p gj p x w x ww. š v ƒ š gj p e w sƒw» w r p x w œ y sƒw, š gj p x w v y z sƒw. zw š gj p 80 MPa( t 96 MPa), x z d w Table x p š ü S, v K q š w. e { ü š Fig. 1. SEM f raw materials. w eù w, e { w š v 14,000 (Blaine, cm /g) š ü W 2 w w. k w š x w v w y w. ƒ yy yw Table 2. Fig. 1 SEM w e {, v, š v x w, š v e { x w e,» OPCù š x w ƒ ù š, v š x û w e. x w, 19 mm w w. š AE ü W š w t w. 2.. x d x e { š v sƒw» w š gj p y z w sƒ p r p w sƒƒ w. w Table 1 x z w x, gj p œ w. š š v 44«9y(2007)

3 504 Á½ ³Á½ Á Á e { š gj p y e w sƒw» w v w yp w» w p r p x w. ƒ x d ¾ z d w, x w x ww d w d 1) gj p ƒ yy y» s ƒwš, š v ƒ swwš k w yy mw» w x ww. x w z v v x š w w 1 z y d w. 2) š gj p d KS F 2405 gj p w ww. ) y y w x w gj p w e, ³ wù š v e { š gj p e w w» w y d w. y mw» w w 50% Cnductin calrimeter 7 w y d w. 4) y w ƒ ùkù y x y w» w XRD 5~65 d w š, y Ca(OH) 2 ( w CH w) C-S-H y w DT-TGA 10 C/min 25~1000 C¾ d w, y w» w SEM Fig. 2. Fluidity f fresh cncrete. ww. 5) œ e { w š gj p š w y s w œ œ ƒ, e { š v w w œ w» w pr p œ 1 1 1cm j» w y z (Mercury Intrusin Prsimetry, MIP) w d w. x 10~60,000 psi.2 nm l 50 µm œ œ j» s w.. x š.1. gj p p v w w k w yy w w. š v gj p e w» w w z 1 z y w Fig. 2. Fig. 2 e { w x w š v w x v v ƒ wš, v v ƒ 50 cm w ƒw ù, v v ƒ 55 ±5cm ƒ j š š v 10% w ùkû. š v w v ƒ jš v k šƒ 1) w z ƒ k w d š v e { ƒ w..2. p r p yp.2.1. y p m yy w z 7 y y y ƒƒ Table Fig. ùkü. 7 ¾ y OPC w ƒ ùkùš, y Plain>SF-5> FFA-10>FFA-5>SF-10 ùkùš. y e { w e { w» z ƒ yw y š š, e { w š v 10% w w wz

4 š gj p e { š v m 505 Table. Ttal Hydratin Heat fr 7 Day Specimen OPC Plain SF5 SF10 FFA5 FFA10 Hydratin heat (J/g) Fig.. Hydratin heat accrding t time. vjƒ ùkû. s³,» y 4) j, 2,) Y. Halse v 1 vj w š w, x š v 10% w w w w y, w XRD Fig. 4 ùküš. 10 z p ƒ p r p vj» d w»ƒ. OPC100 x w e { w CH w ù š v w CH w ùkû. ù š v w CH w e {» w e, š v z w w e q. w w 1 ƒƒ d SEM. Fig. 5 1 x SEM w w, p» p ƒ pƒ j e w, x š œ p ƒ pƒ w e w. OPC w w p ƒ p C-S-H š, e{ w C-S-Hƒ ù š v w y š y. š v w x. ù š v w 1 CH C-S-H y. w š v w 1 ¾ j z ¾ š w w 1 z C-S-H z ùkû. w š v 10% w OPC 100% x w x w C-S-H š, XRD 11 z y w š v y w s w w SiO 2 CH w C-S-H. Fig. 4. XRD patterns accrding t the age. 44«9y(2007)

5 이범식 김상규 김상연 최선미 이건수 506 Fig. 5. Fig. 6은 SEM images accrding t the age. 재령 일에 결합재에 따른 DT-TGA 측정결 과를 그래프로 나타낸 것이고, Table 4는 TGA측정에 의 한 온도에 따른 질량 감량율을 나타낸 것이다. 일반적으 로 알려진 수화물들의 온도에 의한 변화는 C-S-H계 수화 물은 100~10 C에서 탈수, 에트링가이트는 100 C 이하 및 100 C, 160~180 C에서 최대피크를 보이며, 250~270 C에서 작은 피크를 보이며 단계적으로 탈수한 다. 또한 모노설페이트는 50~150 C 및 200~00 C에서 세단계로 탈수하고, CH는 400~500 C에서 물과 CaO로 분 해된다고 보고되고 있다. Fig. 6에 의하면 100 C 전후와 170 C 근처의 피크는 에 트링가이트와 모노설페이트의 탈수에 의한 것이라 사료 되며 이 피크는 고분말 플라이애시를 사용한 경우 가장 5) Fig. 6. DT-TGA curve at the day curing. 한국세라믹학회지 크게 나타나고 있고, 이를 통해 고분말 플라이애시는 초 기의 모노설페이트 및 CAH상 생성에 영향을 미친다고 사료된다. 또한 450 C 전후에서의 흡열 피크는 CH의 피크로 재 령 일에 OPC가 가장 크고, Plain, 실리카흄, 고분말 플 라이애시 순으로 나타났다. 이러한 경향은 TGA곡선을 보 아도 동일하게 나타나며, 감량을 정량화 해본 결과 OPC >Plain>SF-5>FFA-10>FFA-5>SF10의 순으로 나타났다. OPC만을 사용한 경우는 재령 일에 최종 CH생성량이 14.9%로 나타났고, 실리카흄 10%의 경우 5.5%, 고분말 Results f Gravimetric Thermal Analysis f Cement Pastes after, Days Curing Cmpsitin f blend Weight lss (%) Ca(OH)2 age 100(wt %) (day) 420C 480 C 1000C wt (%) OPC Plain SF FFA Table 4.

6 š gj p e { š v m 507 Table 5. Results f Prsimetry f Cement Pastes after, Days Curing Cmpsitin f blend Plain SF FFA (wt %) age (day) Prsity (%) Ttal pre Median pre vl (ml/g) Diameter (nm) Fig. 7. Prsity f cement paste accrding t the age. Fig. 8. The distributin curve f pre size. v 10% 7.2% ùkû. w OPC w yy w ƒ p w s Fig. 9. Pre size distributin f cement paste. w w... œ Table 5 prsimeter d w œ, œ, s³ œ w ùkü š, Figs. 7~9 Table 5 ùkù vyw ùkü. gj p œ ùkü œ œ, œ s, Fig. 7 œ r» Plain w e { w w w œ ùkü, š v yww ƒ ƒ œ ùkü š v» z w. ù» š v ƒ œ œ w SEM š v z z w. Fig. 8 œ s ùkü» OPC 100% x ƒ ƒ û ùk ü ù, œ j» wš š v w x ƒ œ ƒ ùkù. Fig. 9 w w» 10 ~ 50 nm œ s, 5nm w œ œ j»ƒ. w w OPC w s yy yww. s ƒ SiO 2ƒ p y CH yww ³ e (CaO SiO 2 nh 2 O) g y w jš,» y 44«9y(2007)

7 508 Á½ ³Á½ Á Á Fig. 10. Cmpressive strength f cncrete. Fig. 11. Relatinship f cmpressive strength with prsity. w z ùkü. w OPC w w x j œ š 10 nm w œ w j» w. Fig. 10 ƒ w Plain w w.» e { š v w ƒ wš ù 7 5% ƒ Plain w w ùkü,» Plain w zw, ƒw w ùkû. x t 80 MPa w e{ w 5%, š v w ƒ j 100 MPa w ùkû. Fig. 11 w s ƒ w œ yƒ e w» w œ v txw. œ w ƒ š, œ w ƒw. s ƒ z s w CH e f p y y w œ, œ» q. 4. š v e { š gj p w» w» w» w w x mw w. 1. š v w š w wƒ w ù, š v ƒ ƒw ƒ w ùkû. 2. XRD SEM mw y, š v» wù z e{ w ùk ü.. œ, OPC w x w y y w ƒ ùkû. e { w w š v w û œ ùkü. w yy w» œ ƒ y ùk û. w w w ƒ š, š v w ƒ œ w ƒ xw ùkû. 4. e { 5% w yp w e ùkû ù, š v 10% w 5% w p ùkü e { w š g j p x d ƒ w. Acknwlengement m 05 w» ( y :05 w D11) w w š g j p w šd œ k Ì ¾. REFERENCES 1. K. Ogawa, Uchikawa, and K. Takemt, The Mechanism w wz

8 š gj p e { š v m 509 f the Hydratin in the System C S-Pzzlania, Cement and Cncrete Reserch, 10 [5] (1980). 2. D. Kuni and O. Levenspi, Fludizatin Engineering, Butterwrth Heineman Series in Chemical Engineering, pp. 6, Academic Press, Wei Fajun, Michael W. Grutzeck, and Della M. Ry, The Retarding Effects f Fly Ash upn the Hydratin f Cement Pastes, The first 24 hurs, Cem. Cncre. Res., 15 [1] (1985). 4. Y. Halse, P. L. Pratt, J. A. Dalziel, and W. A. Gutteridge, Develpment f Micrstructure and ther Prperties in Fly Ash OPC Systems, Cem. Cncr. Res., 14 [4] (1984). 5. H. Sng, K.-J. Mun, and Y.-S. Sh, Mechanical Prperties and Pre Structure f Cement Matrix at High Temperature(in krean), J. f Prceeding f Architectural Institute f Krea, 20 [1] (2004). 44«9y(2007)