施工性および品質を改善した ... - obayashi.co.jp

1 2014 1 Development and Application of Concrete for Improved Workability and Quality Masanori Tsuzuki Yasumichi Koshiro Masaki Sakai Abstract Flowing concrete having fluidity and material separation resistance was applied to the construction of a new laboratory at our technical research institute for improved workability, and low drying shrinkage concrete using an expansive additive and reducing shrinkage agent was applied for improved quality. Compared with concrete having a slump of 21 cm, the highly fluid concrete reduced the unit cement content, and the slump loss from the mixing time was small.

2 Moreover, the concrete filled the spaces between the rebars of a heavily reinforced structural member without material separation. For the low drying shrinkage concrete, the drying shrinkage strain was 200 250 10-6 when the amount of expansion was considered. It prevented cracking of the structural slab. 21cm 200 250 10-6 1.

3 JASS5 (2009) 15 10cm 1) 10cm 2) 2.

4 AE 21cm AE 8cm 21cm 27 AE 21cm( 21 2cm) ( SL21) AE 8cm( 8 ) 21cm( 21 2cm) ( FL21) 2 7 Table 1 (C) 2 (S) (G) AE (AE) AE (SP) FL21 18cm 575L/m3 FL21 SL21 14kg/m3 10kg/m3 SL21 30 120 FL21 30 90 (JIS A 1108) (JIS A 1149) (JIS A 1147) (JIS A 1123) Table 2 Fig.

5 1 28 C 140 33 C SL21 60 16cm FL21 60 20cm 90 15cm 90 140 SL21 15cm C Fig. 2 Fig. 3 FL21 SL21 FL21 FL21 90 SL21 FL21 Table 3 25kg/m3 ( EX25) 20kg/m3 6kg/m3 ( EX20-SR6) 2 27 (G) Table 1 Mixture Proportion of Flowing Concrete W/C s/a(%)(cm)(%) FL21 C (kg/m3)

6 Table 2 Basic Properties of Concrete Fig. 1 Change of Slump Value Fig. 2 Result of Bleeding Test Fig. 3 Result of Setting Time Test 1 Air ( C)(cm)(cm)( )(N/mm2)(kN/mm2)SL21 1 2: 28 FL21 2 6912151821240306090120150180 (cm) SL21FL21 cm3/cm2 ( SL21FL21- FL21- 01020304050012345678910 (N/mm2) ( SL21FL21- FL21- (=28N/mm2) (= ) 3 (EX) (SR) (C)))

7 15 Table 4 7 20 2 C 5% 1 3 (JIS A 1151) Fig. 4 JIS 7 ( ) Table 5 26 C ( 30 ) 3 4cm 28 Table 6 35 38N/mm2 30kN/mm2 (JIS A 1129) 182 (6 ) EX25 450 10-6 EX20-SR6 400 10-6 (JIS A 6202- 2)

8 A ( ) ( 7 ) 250 10-6 EX20-SR6 200 10-6 ( )( )WSR CEXS1S2S3EX25170-30225296297254EX20-SR61 64630720297297255AE B W'/B Air (kg m3)W'BSGT able 3 Mixture Proportion of Low Drying Shrinkage ConcreteTable 4 Measurement Item and Method JIS JIS A 1108 10 20cm JIS A 1149 10 20cm JIS A 1113 10 20cmJIS A 1129-2 10 10 40cmJIS A 6202 2 A 10 10 40cmJIS A 1151 Fig.

9 9 9401705050 (mm) 600100 ( ) ( ) H B=100 50mm 100mmFig. 4 Schematic of Uni-Axial Restraint Specimen Table 5 Fresh Properties SL (cm)( )( C)(cm)( )( C)6 1 SL Air 2 30 2EX25 EX20-SR6 (N/mm2)(kN/mm2)(N/mm2) 6 Strength Properties -300-200-10001002003000 30 60 90 120150180 ( 10-6) ( )EX25 7 0 30 60 90 120150180 ( )EX20-SR6 7 Fig. 5 Shrinkage Strain Considered Amount of Expansion 4 JIS A 6202 189 EX25 EX20-SR6 200 10-6 Fig.

10 6 EX20-SR6 EX25 150 180 60 10-6 150 3. (Photo 1 ) 5m 24m 2m Photo 2 125mm D32 3 1m PC 500mm 2 (1 800mm 2 1,200mm) 30 9 14 Fig.