“The concrete mix is designed as per absolute volume method according to the Indian standard -Concrete mix proportioning Guidelines to meet environmental exposure condition of Mumbai city, Maharashtra i.e., considered sever condition” [13]. “The properties of the concrete ingredients differ from one state to another state of the same country, and it is totally depending on actual environmental exposer condition of site and quality of available concrete ingredients for making suitable concrete mix” [14].
Concrete mix compositions are presented in Table 6 & Table No-7.
Table 6. Concrete Mix Proportions for Tunnel NATM Lining concrete M40 Grade [1].
Sr.
No.
|
Mix
|
Cement
(Kg/m3)
|
GGBS
(Kg/m3)
|
UGGBS (Kg/m3)
|
Powder (Kg/m3)
|
W/P
Ratio
|
C.A
(Kg/m3)
|
F.A
M-Sand
(Kg/m3)
|
C.A /FA ratio (%)
|
Water
(Kg/m3)
|
Superplasticizer-Sika ViscoCrete 5138
(Kg/m3)
|
1
|
TR1
|
330
|
150
|
20
|
500
|
0.3
|
999
|
883
|
53/47
|
150
|
9.0
|
2
|
TR2
|
350
|
150
|
20
|
520
|
0.317
|
930
|
851
|
52/48
|
165
|
7.02
|
3
|
TR3
|
360
|
160
|
20
|
540
|
0.309
|
1029
|
773
|
57/43
|
167
|
8.1
|
4
|
TR4
|
360
|
160
|
20
|
540
|
0.296
|
927
|
848
|
52/48
|
160
|
8.64
|
5
|
TR5
|
330
|
200
|
20
|
550
|
0.32
|
778
|
981
|
44/56
|
176
|
7.7
|
Five concrete mix design trials were taken of M40 Grade and finalized TR 5 for NATM Lining flowable concrete for applicating in NATM tunnel and Cross passages of underground Mumbai Metro Project in Package- UGC-07, Line -3. “Coarse aggregate content, fine aggregate content and cementitious content were optimized, until a slump flow of 500-700 mm is achieved by slump flow test. For each trial, tests are carried out in order that the trial mix satisfies slump flow test, T500, V-funnel and Sieve segregation resistance tests” [1].
Table 7. Concrete Mix Proportions for the structures -Base slab, RCC walls and Roof slab Flowable Concrete M40 Grade [1].
Sr.
No.
|
Mix
|
Cement
(Kg/m3)
|
GGBS
(Kg/m3)
|
UGGBS (Kg/m3)
|
Powder (Kg/m3)
|
W/P
Ratio
|
C.A
(Kg/m3)
|
F.A
M-Sand
(Kg/m3)
|
C.A /FA ratio (%)
|
Water
(Kg/m3)
|
Superplasticizer-Sika ViscoCrete 5229 NS
(Kg/m3)
|
C.W.A
(Kg/m3)
|
1
|
TR6
|
315
|
145
|
20
|
480
|
0.313
|
1049
|
816
|
56/44
|
150
|
7.2
|
4.8
|
2
|
TR7
|
260
|
200
|
20
|
480
|
0.304
|
1064
|
814
|
56/44
|
146
|
6.72
|
4.8
|
3
|
TR8
|
260
|
200
|
20
|
480
|
0.313
|
1035
|
810
|
56/44
|
150
|
6.24
|
4.8
|
4
|
TR9
|
245
|
200
|
15
|
460
|
0.35
|
988
|
889
|
53/47
|
161
|
5.98
|
4.6
|
Four concrete mix design trials were taken for the structures -Base slab, RCC walls and Roof slab Flowable Concrete M40 Grade for metro Station in UGC-07 of Mumbai Metro Project, Line -3. Acceptable results achieved in concrete trial mix no-TR 9. “Coarse aggregate content, fine aggregate content and cementitious content were optimized, until a slump flow of 500-700 mm is achieved by slump flow test. For each trial, tests are carried out in order that the trial mix satisfies slump flow test and Sieve stability tests” [1].
3.1 Test Procedures
“Flowable Concrete is able to flow under its self-weight without segregation, bleeding without vibration and these behavior of concrete can be ensured by Flowability tests, and Sieve segregation resistance tests of concrete to determine the flow ability, passing ability and segregation resistance of Flowable according to BS: EN 12350 Part 8, 9, 10, 11, and 12” [15]
Table 8. NATM Lining flowable concrete M40 Grade – “Flowing ability, passing ability and segregation resistance are checked after 3 hrs. and results are as below” [1].
Sr.No
|
Mix
|
Slump flow (mm)
|
T500
(sec)
|
|
V-funnel
Tf (sec)
|
V-funnel
T5min
(sec)
|
L-box
Blocking ratio(H2/H1)
|
U-box
Difference
(mm)
|
Segregation
Resistance
|
Remarks
|
1
|
TR1
|
430
|
45.0
|
|
98
|
103
|
0.25
|
280
|
-
|
Not achieved
|
2
|
TR2
|
450
|
37
|
|
91
|
98
|
0.3
|
230
|
-
|
Not achieved
|
3
|
TR3
|
470
|
31
|
|
65
|
69
|
0.5
|
140
|
-
|
Not achieved
|
4
|
TR4
|
510
|
16
|
|
27
|
41
|
0.7
|
28
|
11.2
|
Results are found satisfactory for flowability only
|
5
|
TR5
|
540
|
5
|
|
19
|
22
|
0.76
|
22
|
7.9
|
Results are found more satisfactory in flowability requirements and passing ability tests
|
Trial mix no TR 4 has achieved all the requirements of filling ability but could not achieve the requirements of passing ability. In trial No-TR 5 achieved all the requirements of filling ability and passing ability but values are found closer to the requirements. Trial mix no TR5 has been finalized based on above-mentioned tests results values with considering TR5 can be achieved all the parameters of flowing and passing ability at site if apply some vibration during casting the structure.
Details of final NATM Lining flowable concrete M40 Grade mix design trial mix no- TR5 is as below.
TABLE 9: Table showing the finalized mix proportion for the flowable concrete Trial Mix No- TR 5
NATM Lining flowable concrete M40 Grade (10 MSA) [1]
Cementitious (Kg)
|
Water (Kg)
|
Fine Aggregate
M-Sand (kg)
|
Coarse aggregate (10 MSA) (Kg)
|
Superplasticizer (Kg)
|
`Cement
|
GGBS
|
UGGBS
|
176
|
981
|
778
|
7.7
|
330
|
200
|
20
|
Table 10. Test Results of NATM Lining flowable concrete M40 Grade in Laboratory [1]
Test Observation
|
Property
|
Acceptance Limits as per European Guideline
|
Initial
|
1hr
|
2hrs
|
3 hrs.
|
Slump-flow class SF1
|
Flowability/Filling Ability
|
≥ 520mm, ≤ 700mm
|
630
|
6 10
|
580
|
540
|
T500
|
Viscosity Flowability
|
between 3-7 Sec
|
4
|
4
|
4.5
|
5
|
V5min
|
viscosity Flowability
|
---
|
18
|
22
|
24
|
28
|
V Funnel Tv
VF 2
|
Viscosity Flowability
|
≥ 7S, ≤ 27s
|
14
|
16
|
18
|
24
|
L Box (H2/H1)
|
Passing Ratio
|
≥ 0,75
|
0.8
|
0.8
|
0.78
|
0.76
|
U Box Deference
|
Height difference
|
30 mm Max
|
0
|
15
|
19
|
22
|
Sieve Segregation
|
Segregation Resistance
|
< 23 %
|
9.5
|
9.2
|
8.4
|
7.9
|
Ambient Temperature
|
|
26.5
|
27.5
|
28.2
|
29.4
|
“Mix proportion of selected mix design TR5 implemented at site for Tunnel NATM concrete and NATM cross passages and total 11426 cum concrete quantity is executed from 25th Feb 2020to 30th june’2021.The flowing ability and passing ability of concrete mix are checked according to conformity criteria for the properties of Flowable concrete at site and observed results are as below” [4].
Table 11. The Average Test Results of Site executed Flowable concrete mix during concreting for Tunnel NATM Lining Concrete.
Test Observation
|
Property
|
Acceptance Limits as per European Guideline
|
Results obtained at Batching Plant
|
Results obtained (around 1 to 2 hrs after batching time)
|
Remarks
(Comparison with 2 hrs results of
TR 9)
|
|
Slump-flow class SF1
|
Flowability/Filling Ability
|
≥ 520mm, ≤ 700mm
|
630
|
560
|
-20 mm than TR 5
|
|
T500
|
Viscosity Flowability
|
between 3-7 Sec
|
4
|
6
|
-1.5 sec than TR5
|
|
V5min
|
viscosity Flowability
|
---
|
-
|
-
|
Not Taken
|
|
V Funnel Tv
VF 2
|
Viscosity Flowability
|
≥ 7S, ≤ 27s
|
-
|
-
|
Not Taken
|
|
L Box (H2/H1)
|
Passing Ratio
|
≥ 0,75
|
-
|
-
|
Not Taken
|
|
U Box Deference
|
Height difference
|
30 mm Max
|
-
|
-
|
Not Taken
|
|
Sieve Segregation
|
Segregation Resistance
|
< 23 %
|
-
|
-
|
Not Taken
|
|
Ambient Temperature
|
|
26.5
|
27.5
|
28.2
|
-1.2 deg at site
|
|
All the parameters of tests are not checked at the site due to the fact shifting of all checking out equipment couldn't nearly possible at some point of concreting at the site, but slump flow, T 500 mm checks, and the temperature had been executed for 1904 transit mixers and their common values are cited in above table.
A few tests could not be conducted at the site laboratory due to the non-availability of sufficient testing apparatus at in house laboratory. Consequently, samples of specimens were sent to a third-party laboratory for undertaking assessments areas underneath.
Table 12. Hardened Concrete Test results for Tunnel NATM Lining Concrete [1].
Sl. NO.
|
Test Description
|
Acceptance Requirement as per contract specification
|
Actual Results obtained
|
1
|
RCPT
|
1000 Coulombs
|
782.0 coulombs
|
2
|
Permeability
|
10 mm
|
6 mm
|
3
|
Flexural strength
|
> 0.7 √fck
= 5.42 N/mm2
|
6.25 n/mm 2
|
4
|
Split tensile strength
|
> 0.5 √fck
= 3.87 N/mm2
|
5.01 n/mm 2
|
5
|
Drying Shrinkage
|
0.05 % (Max)
|
0.026 %
|
6
|
Moisture Moment
|
0.03 % (Max)
|
0.018 %
|
7
|
Chloride content
|
0.5 % (Max)
|
0.34 %
|
8
|
Sulphate content
|
3.7 % (Max)
|
0.35 %
|
Table 13. The Cube Compressive Strength for Successful Trial Mix no TR-5 for M40 NATM Lining Flowable Concrete in N/mm2 [1]
Sr. No
|
Age of Cubes
|
No. Cubes Tested
|
Compressive Strength of Cubes in N/mm2
|
Avg. Compressive Strength of each Sample in N/mm2
|
Avg. Strength of Samples in N/mm2
|
1
|
7 days
|
9
|
39.6
|
40.81
|
40.14
|
2
|
41.2
|
3
|
41.63
|
4
|
38.5
|
39.58
|
5
|
41.24
|
6
|
38.99
|
7
|
41.66
|
40.02
|
8
|
38.99
|
9
|
39.41
|
10
|
28 days
|
18
|
58.54
|
59.52
|
61.34
|
11
|
63.49
|
12
|
56.53
|
13
|
63.21
|
60.33
|
14
|
59.56
|
15
|
58.22
|
16
|
59.73
|
62.45
|
17
|
63.24
|
18
|
64.38
|
19
|
62.98
|
61.63
|
20
|
61.22
|
21
|
60.69
|
22
|
59.77
|
61.66
|
23
|
58.55
|
24
|
66.66
|
25
|
60.12
|
62.45
|
26
|
58.9
|
27
|
68.33
|
28
|
56
|
9
|
76.22
|
70.46
|
68.88
|
29
|
75.02
|
30
|
60.14
|
31
|
67.43
|
68.69
|
32
|
66.23
|
33
|
72.41
|
34
|
68.93
|
67.49
|
35
|
67.73
|
36
|
65.81
|
“After achieving all the parameters according to the requirements of site conditions for Flowable concrete for grade M40 then same mix is implemented site for the construction of NATM tunnel lining and cross passages. The compressive strength results of site casted cubes for 7 days,28 days and 56 days are represented in table and graph as below” [1].
Table 14. The Compressive Strength of site casted cubes for M40 grade Flowable Concrete (in N/mm2) [1]
SI. No
|
Age of casted Cubes
|
No. Samples
|
Avg. Compressive Strength of Samples in N/mm2
|
% Of Compressive Strength Gaining
|
Standard Deviation in N/mm2
|
% Of Coefficient of Variation
|
1
|
7 days
|
8
|
40.14
|
100.35
|
1.82
|
3.03
|
2
|
28 Days
|
35
|
60.22
|
150.55
|
3
|
56 days
|
8
|
65.09
|
162.73
|
Concrete cubes have been casted for testing of compressive strength for ongoing working structures and results are found satisfactory. Samples taken for cube compression strength of working structures, average compressive strength, standard deviation, and coefficient of variation are represented in the graph as beneath.
Table 15. RCC works Flowable Concrete M40 Grade - Flowing ability, passing ability and segregation resistance are checked after 3 hrs. and results are as below [1].
Sr.No
|
Mix
|
Slump flow (mm)
|
T500
(sec)
|
|
V-funnel
Tf (sec)
|
V-funnel
T5min
(sec)
|
L-box
Blocking ratio(H2/H1)
|
U-box
Difference
(mm)
|
Segregation
Resistance
|
Remarks
|
1
|
TR6
|
380
|
53
|
|
-
|
-
|
-
|
-
|
-
|
Not achieved
|
2
|
TR7
|
450
|
45
|
|
-
|
-
|
-
|
-
|
-
|
Not achieved
|
3
|
TR8
|
450
|
31
|
|
91
|
98
|
0.3
|
230
|
6.8
|
Not achieved
|
4
|
TR9
|
530
|
7
|
|
21
|
26
|
0.6
|
36
|
7.5
|
Results are found more satisfactory in flowability requirements and near to passing ability tests
|
In trial No-TR 9 achieved all the requirements of filling ability and passing ability values are found nearer to the requirements. Trial mix no TR 9 has been finalized based on above-mentioned tests results values with considering TR9 can be achieved all the parameters of flowing and passing ability at site with apply some vibration during casting the structure to get the smooth surface finish.
Details of final RCC works Flowable Concrete M40 Grade mix design trial mix no- TR 9 is as below.
TABLE 16. Table showing the finalized mix proportion for Flowable Concrete, Trial Mix No- TR 9
RCC works Flowable Concrete M40 Grade (20 MSA) [1]
Cementitious (Kg)
|
Water (Kg)
|
Fine Aggregate
M-Sand (kg)
|
Coarse aggregate (20 MSA) (Kg)
|
Superplasticizer (Kg)
|
C.W.A
(Kg)
|
`Cement
|
GGBS
|
UGGBS
|
161
|
889
|
988
|
5.98
|
4.6
|
245
|
200
|
15
|
Table 17. Test Results of RCC works Flowable Concrete M40 Grade in Laboratory [1]
Observation
|
Characteristics
|
Acceptance Limits
|
Initial
|
1hr
|
2hrs
|
3 hrs.
|
Slump-flow class SF1
|
Flowability/Filling Ability
|
≥ 520mm, ≤ 700mm
|
600
|
580
|
540
|
530
|
T500
|
Viscosity Flowability
|
between 3-7 Sec
|
4
|
4
|
5
|
7
|
V5min
|
viscosity Flowability
|
---
|
16
|
18
|
23
|
26
|
V Funnel Tv
VF 2
|
Viscosity Flowability
|
≥ 7S, ≤ 27s
|
13
|
16
|
18
|
21
|
L Box (H2/H1)
|
Passing Ratio
|
≥ 0,75
|
0.75
|
0.7
|
0.65
|
0.6
|
U Box Deference
|
Height difference
|
30 mm Max
|
23
|
26
|
31
|
36
|
Sieve Segregation
|
Segregation Resistance
|
< 23 %
|
9.5
|
9.2
|
8.4
|
7.5
|
Ambient Temperature
|
|
|
27.5
|
28.2
|
29.4
|
Mix proportion of selected mix design TR9 implemented at site for RCC structures i.e., Base slab, Roof slab and RCC walls and total 32508 cum concrete quantity is executed from 18th March 2020to 30th june’2021.
“The flowing ability of concrete mix are checked according to conformity criteria for the properties of Flowable concrete at site and observed results are as below [4].
Table 18. The Average Test Results of Site executed flowable concrete mix during concreting for RCC structures [1].
Test Observation
|
Property
|
Acceptance Limits as per European Guideline
|
Results obtained at Batching Plant
|
Results obtained (around 1 to 2 hrs after batching time)
|
Remarks
(Comparison with 2 hrs results of
TR 9)
|
Slump-flow class SF1
|
Flowability/Filling Ability
|
≥ 520mm, ≤ 700mm
|
590
|
560
|
+ 20 mm than TR 9
|
T500
|
Viscosity Flowability
|
between 3-7 Sec
|
4
|
6.5
|
+1.5 sec than TR9
|
V5min
|
viscosity Flowability
|
---
|
-
|
-
|
Not Taken
|
V Funnel Tv
VF 2
|
Viscosity Flowability
|
≥ 7S, ≤ 27s
|
-
|
-
|
Not Taken
|
L Box (H2/H1)
|
Passing Ratio
|
≥ 0,75
|
-
|
-
|
Not Taken
|
U Box Deference
|
Height difference
|
30 mm Max
|
-
|
-
|
Not Taken
|
Sieve Segregation
|
Segregation Resistance
|
< 23 %
|
-
|
-
|
Not Taken
|
Ambient Temperature
|
|
|
27.5
|
28.2
|
29.4
|
“All the parameters of tests are not checked at site because shifting of all testing apparatus could not practically possible during concreting at site, but Slump flow, T500 and temperature tests were carried out for 5118 Transit Mixers and their average values are mentioned in above table” [1].
A few tests could not be conducted at the site laboratory due to the non-availability of sufficient testing apparatus at in house laboratory. Consequently, samples of specimens were sent to a third-party laboratory for undertaking assessments areas underneath.
Table 19. Hardened Concrete Test results for RCC works Flowable Concrete M40 Grade
[1]
Sl. NO.
|
Description of Tests
|
Acceptance Requirement of contract specifications
|
Results obtained
|
1
|
Permeability
|
10 mm
|
4 mm
|
2
|
RCPT
|
1000 Coulombs
|
652.5 coulombs
|
3
|
Split tensile strength
|
> 0.5 √fck
= 3.87 N/mm2
|
4.66 n/mm 2
|
4
|
Flexural strength
|
> 0.7 √fck
= 5.42 N/mm2
|
6.10 n/mm 2
|
5
|
Drying Shrinkage
|
0.05 % (Max)
|
0.009 %
|
6
|
Moisture Moment
|
0.03 % (Max)
|
0.011%
|
7
|
Chloride content
|
0.5 % (Max)
|
0.22 %
|
8
|
Sulphate content
|
3.7 % (Max)
|
1.87 %
|
Table 20. The Cube Compressive Strength for Successful Trial Mix no TR-9 for M40 Grade flowable concrete in N/mm2 [1].
Sr.No
|
Age of Cubes
|
No. Specimen
|
Compressive Strength of Specimen in N/mm2
|
Compressive Strength of Sample in N/mm2
|
Avg. Strength of Samples in N/mm2
|
1
|
7 days
|
9
|
34.6
|
35.81
|
35.14
|
2
|
36.2
|
3
|
36.63
|
4
|
33.5
|
34.58
|
5
|
36.24
|
6
|
33.99
|
7
|
36.66
|
35.02
|
8
|
33.99
|
9
|
34.41
|
10
|
28 days
|
18
|
52.54
|
53.52
|
55.34
|
11
|
57.49
|
12
|
50.53
|
13
|
57.21
|
54.33
|
14
|
53.56
|
15
|
52.22
|
16
|
53.73
|
56.45
|
17
|
57.24
|
18
|
58.38
|
19
|
56.98
|
55.63
|
20
|
55.22
|
21
|
54.69
|
22
|
53.77
|
55.66
|
23
|
52.55
|
24
|
60.66
|
25
|
54.12
|
56.45
|
26
|
52.9
|
27
|
62.33
|
28
|
56 days
|
9
|
73.22
|
67.46
|
65.88
|
29
|
72.02
|
30
|
57.14
|
31
|
64.43
|
65.69
|
32
|
63.23
|
33
|
69.41
|
34
|
65.93
|
64.49
|
35
|
64.73
|
36
|
62.81
|
“After achieving all the parameters according to the requirements of site conditions for Flowable concrete for grade M40 then same mix is implemented site for the construction of RCC structures i.e., Base Slab, Roof slab and RCC walls. The compressive strength results of site casted cubes for 7 days,28 days and 56 days are represented in table and graph as below” [1].
Table 21. The Compressive Strength of site casted cubes for M40 grade Flowable Concrete (in N/mm2) [1]
Sr.No
|
Age of Cube
|
No. Sample
|
Avg. Strength of Samples (N/mm2)
|
% Of Strength Gaining
|
Standard Deviation (N/mm2)
|
Coefficient of Variation (%)
|
1
|
7 days
|
9
|
33.87
|
84.68%
|
1.77
|
3.48
|
2
|
28 Days
|
35
|
50.81
|
127.03
|
3
|
56 days
|
9
|
61.91
|
154.78
|
“Concrete cubes have been casted for testing of compressive strength for ongoing working structures and results are found satisfactory. Samples taken for cube compression strength of working structures, average compressive strength, standard deviation, and coefficient of variation are represented in the graph as beneath” [1].