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1 w y wz 10«3y 259~264 ( ) Journal of Korean Society of Urban Environment w gj p p y Á Á½k * w m œw Á* w y œw ( , k) Characteristics of Antiwashout Underwater Concrete for Reduction of Water Contamination Su-Ho Bae ½ Jae-Im Park ½ Tae-Dong Kim* Department of Civil Engineering, Andong National University *Department of Environmental Engineering, Andong National University (Received 28 September 2010 : Accepted 12 October 2010) Abstract The objectives of this experimental research is to investigate the characteristics of antiwashout underwater concrete to reduce water contamination. The overall quality of antiwashout underwater concrete will ultimately be affected by factors such as performance of antiwashout admixture (AWA) and mix proportions of concrete. And the performance of AWA may significantly influence quality of antiwashout underwater concrete. In this study, antiwashout underwater concrete test specimens with water-cement ratio of 50% were made according to brands of AWA, and then their quality performances such as slump flow, setting time, compressive strength, and underwater segregation resistance, etc. were evaluated according to the related specification of Korean Society of Civil Engineers. It was observed from the test results that antiwashout underwater concrete containing AWA was found to considerably improve quality of concrete such as compressive strength and underwater segregation resistance compared to plain concrete and to be able to reduce water contamination. Key Words : Water Contamination, Antiwashout underwater concrete, Antiwashout admixture, Underwater segregation resistance, Compressive strength gj p k w gj pƒ w gj p pƒ ƒ w gj p ü t w œx g y k w e. gj p œ gj p w j» w gj p p ³ w. gj p t ª gj p w w. p, gj p t j w e., - p 50% w tz gj p w, v v,, t sƒw., ƒw gj p m gj p w j gj p œ k ùkû. :, gj p,,, Corresponding author [email protected] 259

2 260 yá Á½k I. gj p k w gj p ƒ w gj p pƒ ƒ w gj p,, ü t w œx g y k w e., gj p œ œx j» w gj p k gj p š. wr, yy gj p yw w, ¼ p p ƒ w w g j p w z ƒ ( w, 1999;, 2000; Khayat, 1995; Otsuki, 1996). gj p œ ù, x w yy ù y w š yy yy š,» v v 500 mm gj pƒ œx š. p,» gj p k w š rv œ yy w gj p t ü w j w j ùkùš, gj p d š w gj p š ( w ³, 2000; ½, 2000; Sonebi Khayat, 1999; Khayat Sonebi, 2001; Khayat Assaad, 2003)., ü q š 5 t w tz w gj p w z, v v,, t» sƒw ( wm wz, 1995). 1. II. x p w H t m sp p w, Table 1. ù w, w, Table 2 3. Table 4 yy (Antiwashout admixture, AWA) š (Superplasticizer, SP ) t p tz ùkü. 2. x 2.1. œ w gj p t sƒw» w gj p w x w, t vv 500 mm, t œ» 4.5% w w, - p 50% g j p w.» gj p œ KS F Table 1. Physical properties of cement Density Setting time (min) Fineness Compressive strength (MPa) (g/cm 3 ) Initial Final (m 2 /kg) f 3 f 7 f Table 2. Physical properties of fine aggregate Specimen Density (g/cm 3 ) Absorption (%) Unit mass (kg/m 3 ) Mass of passing No. 200 sieve (%) River sand (Nakdong river) F.M. Table 3. Physical properties of coarse aggregate Specimen G max (mm) Density (g/cm 3 ) Absorption (%) Unit mass (kg/m 3 ) F.M. Crushed rock (Andong)

3 w gj p p 261 Table 4. Properties of chemical admixture Brands Types Main component Specific gravity A B C D E * Superplasticizer ** Antiwashout admixture SP * Melamine type 1.04 AWA ** Hydroxypropyl methyl cellulose - SP Polycarbonic acid type 1.05 AWA Hydroxypropyl methyl cellulose 1.5 SP Polycarboxylic acid type 1.04 AWA Hydroxypropyl methyl cellulose 0.6 SP Melamine sulfonate type 1.04 AWA Hydroxypropyl methyl cellulose - SP Polycarbonic acid type 1.04 AWA Hydroxypropyl methyl cellulose - Table 5. Mix proportions of antiwashout underwater concrete W/C (%) 50 Brands Target slump flow (mm) Target air content (%) S/a (%) Unit mass (kg/m 3 ) W C S G AWA (W %) SP (C %) Reference w A w B w C w D w E w (gj p x œ ), gj p œ wm wz gj p x œ ( ) w ( wm wz, 1995),» œ w œ sƒw. Table 5 tz gj p wt ùkü gj p KS F 2436( we w gj p x ) d w wm wz gj p yy t ³ ( ) ùw x gj p ph xk Fig. 1 Fig. 1. Testing suction apparatus. e w d w vv wm wz gj p yy t ³ ( ) gj p vv

4 262 yá Á½k Fig. 3. Setting time of antiwashout underwater concrete. Fig. 2. Test set-up of square type box. x gj p vv d w Ux ƒx gj p ùkü ƒ w ùkü. d w» w Fig mm n j z gj p 400 mm¾ š 3 ew, q 5 10 z ƒƒ d w. 1. III. x š Fig. 3 tz w gj p ùkü, 26~33, 28~37 ùkù, D w t wm wz gj p» ( : 5, : 30 ü) ù ùkû. gj p SP w p ùkù q, gj p œ w ƒ. 2. Fig. 4 tz gj p ph xk ùkü, gj p w j ph xk. gj p ph xk ƒƒ 11.4~11.5, 33~82 mg/l wm wz gj p» (ph: 12.0 w, xk : 150 mg/l w) k ùkû., x w gj p w œx k q. 3. vv Fig. 5 tz w gj p vv ùkü, x t t vv (500 mm ) ù {w ùkû. gj p w w SP ƒw» q. gj p wì SP v ùkû.

5 w gj p p 263 Fig. 6. Square type box elevation of head antiwashout underwater concrete. Fig. 4. Undewater segregation of antiwashout underwater concrete. Fig. 5. Slumpflow of antiwashout underwater concrete. 4. Fig. 6 ƒx x e w 5 Fig. 7. Compressive strength ratio of antiwashout underwater concrete. 10 z gj p ùkü, q, 5 10 z ƒƒ 10~85 mm, 6~58 mm ùkû. ƒ w ùkü, tz ù, x t y w ùkû. 5. Fig. 7 tz» gj p w gj p ùkü, 7, w» gj p w gj p ƒƒ 0.78~0.92, 0.82~ ~1.01 ùkù, wm

6 264 yá Á½k wz gj p» , { w x t» gj p w gj p ƒ w ùkû. wr, w w v gj p k yw y x ù kû. IV. gj p œ j» w w gj p t sƒ. 1. w gj p D w t wm w z gj p» w, gj p p ùkù, gj p œ w ƒ. 2. gj p ph xk d, 11.4~11.5, z 33~82 mg/l x t w m wz gj p» g gj p w w ùkû. 3. gj p sƒw» w vv x t t vv (500 mm ) ù {w ùkû. gj p w w SP ƒw» q. 4. gj p 5 10 z ƒx ƒƒ 10~85 mm, 6~58 mm ùkû, ƒ w ùkü, x t yw ùk û. 5. 7, w» gj p w gj p ƒƒ 0.78~0.92, 0.82~ ~1.01 ùk ù, w m wz gj p» , { w x t» gj p w g j p ƒ w ùkû. 6. w gj p t sƒ, w x t wm wz g j p t» j ùkû., x w gj p œ x j k q. References 1. wm wz gj p yy t ³ ( ). wm wz. 2. w, ½, yy sƒ w x. gj pwz. 11(5). pp ,, k³ w k gj p e w. wm wz. 20(4-A). pp w, ³ Ÿ yy yww š gj p». wm w z. 20(2-A). pp w, ½, ³, ³ gj p št y. gj pwz. 12(5). pp Khayat, K. H Effects of Antiwashout Admixtures on Fresh Concrete Properties. ACI Materials Journal. 92(2). pp Otsuki, N., Hisada, M., Nagataki, S., and Kamada, T An Experimental Study on the Fluidity of Antiwashout Underwater Concrete. ACI Materials Journal. 93(1). pp Sonebi, M., and Khayat, K. H Effect of Water Velocity on Performance of Underwater Self- Consolidating Concrete. ACI Materials Journal. 96(5). pp Khayat, K. H., and Sonebi, M Effect of Mixture Composition on Washout Resistance of Highly Flowable Underwater Concrete. ACI Materials Journal. 98(4). pp Khayat, K. M., Assaad, J Relationship between Washout Resistance and Rheological Properties of High- Performance Underwater Concrete. ACI Materials Journal. 100(3). pp