DOI : 10.17577/IJERTV6IS060212
- Open Access
- Total Downloads : 283
- Authors : Er. Jatinder Kumar, Er. Kshipra Kapoor
- Paper ID : IJERTV6IS060212
- Volume & Issue : Volume 06, Issue 06 (June 2017)
- DOI : http://dx.doi.org/10.17577/IJERTV6IS060212
- Published (First Online): 08-06-2017
- ISSN (Online) : 2278-0181
- Publisher Name : IJERT
- License:
This work is licensed under a Creative Commons Attribution 4.0 International License
Evaluation for Statistical Analysis of Compressive Strength of Temperature Controlled (TC) Concrete W.R.T. Change in Time as well as Weather Condition
¹ Er. Jatinder Kumar
¹Research Scholar,
Civil Engineering Department,
Universal Institutions of Engineering & Technology, Lalru Mandi
² Er. Kshipra Kapoor
²Associate Professor, Civil Engineering Department,
Universal Institutions of Engineering & Technology, Lalru Mandi
Abstract: The experiments conducted focuses on research to check the response of concrete during the curing period over the time span and environmental condition change. Curing of concrete is directly related to the performance of structural over the life span of the same. But it becomes very critical when the curing has to be placed over the temperature controlled concrete. The case study of this research is to check, how the concrete the compressive strength change with same type of curing, same amount of curing but change in time and environmental weather condition change. The research is evaluated by Well curb statistical analysis report, which is performed in lab under controlled conditions.
Keywords: Temperature controlled (TC) concrete, Statistical Analysis, Compressive Strength of concrete.
INTRODUCTION
High raise Building, Heavy infrastructures likes, bridges, tunnels etc. required the strong and deep foundations. But when sufficient SBC is not available at the required depth, then the size of foundation increase and the volume of concrete also increased. As increase in volume of concrete
will also increase the heat of hydration of process inside the concrete which can develop internal shrinkage cracks, thermal expansion etc. to avoid these problem, generally temperature controlled (TC) concrete is used. These concrete also required the proper curing to achieve the required strength. Temperature controlled (TC) concrete not only reduce the heat of hydration process but also decrease the shrinkage cracks and thermal expansions. Which not only increase the strength of concrete but also stability and life of structure.
Experimental details:
Material Details: The list and details of material used in the experiment is listed below,
-
Cement: The Ordinary Portland cement (OPC) of 53 grade witch is completing the standard requirement of IS 269:2015. The physical properties of cement checked as per IS: 4031 (Part-2) -1999 (RA 2009), IS: 4031 (Part-3 to 6)-1988 (RA 2009) and results area listed in Table-1.
Sl. No.
Name of the test
Value
Requirement as per IS: 12269 – 2013
1
Consistency
29.50%
Not Specified
2
Initial Setting Time
145 min
Shal not be more than 600 Min.
3
Final Setting Time
205 min
Shal not be more than 600 Min.
4
Specific gravity
3.14
5
Fineness of Cement
302 m²/Kg
Shal not be less than 225 m²/Kg
6
Soundness
0.8mm
Shal not be more than 10 mm.
7
Compressive Strength
a. 7 Days
47.0 Mpa
Shal not be less than 37 Mpa
b. 28 Days
62.5 Mpa
Shal not be less than 53 Mpa
8
Density
3.12 g/cc
Not Specified
TABLE: 1 (Physical – Properties of Cement)
The chemical properties of cement checked as per IS: 4032- 1985 (Reaffirmed 2009) and results are listed in Table-2
Sl. No.
Test Conducted
Results ( % )
Requirement as per IS:12269-2013
1
Total Loss on Ignition (% by mas)
2.89
Not more than 4%
2
Insoluble Residue (% by mass), max
2.87
Not more than 4%
3
Ratio of % of Lime to % of silica, Alumina and Iron Oxide as per the formula.
0.89
Not greater than 1.02 and not less than 0.80
4
Ratio of % of Alumina to Iron Oxide
1.25
Not less than 0.66
5
Total Sulphur content calculated as sulphuric anhydride (% by mass)
1.50
Not more than 3.5%
6
Magnesia (MgO). (% by mass)
2.01
Not more than 6%
7
Tricalcium aluminate, (% by mass)
6.76
Not specified
8
Chloride (Cl), (% by mass)
0.017
Not more than 0.10%
TABLE: 2 (Chemical – Properties of Cement)
-
Fine aggregates: Crushed Sand has been brought from crusher yard (Uran, Maharashtra), fine aggregate passing through IS sieve, satisfying to grading Zone-II as per the IS: 383-2016 and details are listed in Table-3. The physical properties are listed in Table-4.
Sl.
No.
Sieve Size
% Passing
LIMITS AS PER IS 383-2016
mm
Crushed Sand
ZONE I
ZONE II
ZONE III
ZONE IV
1
10.000
100.00
100
100
100
100
2
4.500
99.70
90-100
90-100
90-100
95-100
3
2.360
85.00
60-95
75-100
85-100
95-100
4
1.180
52.60
30-70
55-90
75-100
90-100
5
0.600
38.10
15-34
35-59
60-79
80-100
6
0.300
25.60
5-20
8-30
12-40
15-50
7
0.150
19.20
0-10
0-10
0-10
0-15
fineness Modulus
2.80
Note – for crushed stone sands, the permissible limit on 0.150mm sieve is increased to 20%
TABLE: 3 (Fine Aggregates Sieve analysis report)
SL. No.
Test Conducted
Result (Crushed Sand)
1
Specific Gravity
2.79
2
Water Absorption (%)
2.41
3
Bulk density (kg/ litre)
a.
Loose
1.88
b.
Rodded
2.10
/table>
TABLE: 4 (Fine Aggregates Physical Test report)
Course aggregates: Mechanically crushed angular granite stone of size 20mm and 10mm has been used, for different size of sieve used as per IS standard, which is maintained with different proportion of coarse aggregate and conforming to IS:383- 2016 are listed in Table-5. The physical properties are listed in Table-6.
Sl.
No.
Sieve Size
% Passing
Limits as per IS-383-2016 (single sized aggregate)
mm
20 mm
10 mm
20 mm
10 mm
1
40
100.00
100.00
100.00
100.00
2
20
97.00
100.00
85-100
100.00
3
12.5
32.08
100.00
–
100.00
4
10
7.80
85.75
0-20
85-100
5
4.75
0.40
1.55
0-5
0-20
6
2.36
–
1.27
–
0-5
TABLE: 5 (Course Aggregates Sieve analysis report)
SL.
No.
Test Conducted
Result
Limits as per IS-383-2016
20 mm
10 mm
1
Specific Gravity
2.86
2.85
–
2
Water Absorption (%)
1.33
1.44
–
3
Aggregate Impact Value (%) (12.5mm passing through 10 mm retained)
13.2
16.6
Max. 45% non-wearing surface Max. 30% wearing surface
4
Aggregate Crushing Value (%) (12.5mm passing through 10 mm retained)
13.3
16.9
Max. 30% wearing surface
5
Bulk density (kg/ litre)
a.
Loose
1.56
1.53
–
b.
Rodded
1.69
1.65
–
6
Aggregate Abrasion Value (%)
Max. 50% non-wearing surface Max. 30% wearing surface
a.
Grading (B)
13.3
–
b.
Grading (C)
–
15.0
7
Flakiness Index (%)
8.1
12.0
Combined flakiness and elongation index shall not be exceed 40%
8
Elongation Index (%)
12.2
17.2
TABLE: 6 (Course Aggregates Physical Test report)
Chemical admixtures: Polycarboxylate ether based super-plasticizer condensate as high range water reducing admixture (HRWR) to maintain a satisfactory of workability for different mixes with constant w/b ratio throughout the experimental works. The chemical analysis report is listed in Table-7.
Sl.
No.
TEST CONDUCTED
Results
Requirements (as
(RA:2013) Table-2)
per
IS:9103-1999
Test Method
Conformity
1
Dry Material Content, % by mass
31.27
±5% of declared Value
IS:9103:1999 (RA:2013) Clause.10.1 ANNEX E-1
–
2
Asha Content, % by mass
0.48
±5% of declared Value
IS:9103:1999 (RA:2013)
Clause.10.1 ANNEX E-2
–
3
Relative Density at 25ºC
1.105
±0.02% of declared Value
IS:9103:1999 (RA:2013) Clause.10.1 ANNEX E-3.1(b)
–
4
Chloride (as Cl). % by mass
0.012
±10% of declared Value
IS:6925-1973
Clause;5.0
(RA-2008)
–
5
pH Value at 25ºC
6.21
6.0 Minimum
IS:9103:1999 (RA:2013) Clause.10.1 ANNEX E-5
Yes
TABLE: 7 (Admixture Chemical Analysis/ Test report)
Water and Ice: The type of water used for the concrete mix will affect the properties of concrete. So before starting the production of concrete, the physical as well as chemical properties to be check. And when the case arrived for temperature controlled concrete, then become essential to check all factor as per IS code 7861 (Part-1)-1975 to control the temperature of concrete mix. The quantity of ice used for lowering the temperature is calculated as per IS code 7861 (Part-1)- 1975 recommendation and explained below:
Calculation for Ice (to find the quantity of ice to be added in concrete to produce the concrete as per targeted Temperature aggregate): As per IS: 7861 (Part-I) 1975, the calculation of ice requirement to produce the concrete targeted temperature can be calculated.
As per equation 6.2.b (from IS: 7861 (Part-I) 1975).
T = S ( TaWa + TcWc) + ( Ww – Wi) Tw + Wwa Twa – 79.6 Wi S ( Wa + Wc) +Ww +Wi +Wwa S ( Wa + Wc) +Ww +Wi +Wwa
Where
T = Temperature of freshly mixed concrete (ºC);
Ta, Tc, Tw, Twa = Temperature of aggregate, cement, added mixing water, free water on aggregate respectively (ºC);
Wa, Wc, Ww, Wwa, Wi = mass of aggregate, cement, added mixing water, free water on aggregate and ice respectively (Kg);
S = Specific heat of cement and aggregate. (As per IS code it can be taken as 0.22)
Situation- 1 (For M50TC Concrete): As per above equation, the ice requirement will be calculated as per calculated data; T*= 19 ºC, Ta= 36 ºC, Tc= 45 ºC, Tw= 14 ºC
Wa= 1880, Wc= 513, Ww=149, Wwa=0**, Wi= to be identified
*T = Targeted Temperature (as the temperature required during placing of concrete is 21 ºC)
**Wwa taken as zero, as no water sprinkled over aggregate.
19 = 0.22 ( 36×1880 + 45×513) + ( 149 – Wi) 14 – 79.6 Wi
0.22 ( 1880 + 513) +149 +Wi
12833.74 + 19Wi = 19968.3 + 2086 14Wi – 79.6Wi
19Wi + 14Wi + 79.6Wi = 22054.3 12833.74
112.6Wi = 9220.56 Wi = 81.888 Kg
Percentage of Ice will be = (81.888/ 149) x 100 = 54.96% of Ice against Water.
Calculation for Ice (to reduce the water temperature from natural temperature): To reduce the existing temperature of water which is 26ºC to 14ºC, calculate for ice requirement the following equations has performed.
For M50TC Concrete:
To cool 1 g of water by 1ºC required = 4.186 Joule to be removed So (149-81.88)Kg of water by 12ºC required = 4.186x12x67.12×1000
= 3371571.84 Joule to be removed
This energy is then used to melt ice.
Heat of fusion of ice = 333.55 J/g or 0.33355 kJ/g of ice So to change 3371571.84 joule to change= 3371571.84/ 333.55
= 10108g or 10.11 kg of ice
Concrete Mixture proportion and casting of specimens: The mix is designed with the guideline given in IS: 10262:2009 and with the help of ACI-211.1-91. All the details and proportion provided in Table-8. A total of 3 dfferent concrete mixtures were proportioned based on practical requirement of materials. For temperature controlled concrete, Ice is added to water to lower the temperature from its natural temperature level. The concrete mixtures were mixed using 50 litres capacity Pan Mixer (shown in Fig-1) and specimens were casted by using the steel mould of standard cube 150x150x150mm (3 cubes of each mix design). The fresh concrete mixtures in moulds were compacted using table vibrator and the specimens were remoulded after 24 hours after casting and water cured at 27±3ºC until the age of testing at 7 and 28 days as shown in figure 2.
Sl. No.
MATERIAL DESCRIPTION
CONCRETE MIX DESIGN (M50 TC CONCRETE)
1
CEMENT (in Kg)
213
2
FLY ASH
0
3
GGBS
300
4
C. sand
837
5
AGGREGATE
10mm
522
20mm
521
6
WATER (in Litre)
149
7
ADMIXTURE
QTY.
5.64
PERCENTAGE
1.10%
TABLE: 8 – Mix Proportions (Value for 1 cu-m of Concrete)
Fig-1: Pan Mixer (Experimental Setup for Concrete Mixing)
Fig-2: Experimental Setup for Compressive test
Experimental Test Results and Discussion
-
Content:
Statistical Analysis of cube strength of M50 Temp Controlled concrete – As per clause no 15.4 of IS 456:2000 for individual variation of specimens.
Analysis cube strength of M50 Temp. Controlled concrete for %ge strength achievement at 28th day with respect to 56th day strength.
Acceptance criteria as per agreed specification and IS456 table 11, calculation of Standard Deviation, Mean and chances of failure with graphical representations of the analysis.
-
Executive Summary:
-
Total 47 test results are analyzed which are cast during the 1st Jan2015 to 28th Feb 2015.
-
Variation of strengths of specimens is analyzed for max and min variation from average to identify if any specimen is deviating more than 15% form average of three specimens. None of the results are found which are not complying. Hence no test results are discarded.
-
Average achievement of strength at 28th day is 96.0% with respect to 56th day strength.
-
None of the 56 day test results are below characteristic strength i.e. 50 MPa.
-
Established standard deviation for the test results is 2.9.
-
Mean of all the test results is 60.58 MPa against the Targeted Mean Strength 58.3 MPa.
-
Chances of getting low result than 50 MPa is reported as 0.01% compared to the assumed value of 5% (1 low result in 20).
-
No test results are below fck-3 i.e. 47 MPa, hence all the test results are acceptable.
-
Observations:
OBSERVATIONS FROM STATISTICAL ANALYSIS
fck =
50.0
Mean=
60.58
Established Std. Dev. =
2.9
Probability of getting less strength than 50 MPa =
0.01%
Calculated Proportion of low results =
1 in 8844
Calculated Value of Statistical Constant ( t ) =
3.69
Assumed Standard Deviation =
5.0
Accepted Proportion of low results =
1 in 20
Statistical Constant ( t ) taken for Calculation =
1.65
Analysis for Individual variation (Clause 15.4 of IS 456:2000):
Raw data from non corrected tests results
Individual Variation less than 15%
As per IS456 / 15.4
Sl No.
Date Of Casting
Specimen 1
Specimen 2
Specimen 3
AVG CS
(Mpa)
Max
Min
Compliance
1
05.01.2015
67.51
63.02
67.24
65.93
2.4%
4.4%
YES
2
06.01.2015
61.24
64.22
65.60
63.69
3.0%
3.8%
YES
3
08.01.2015
61.11
54.00
58.40
57.84
5.7%
6.6%
YES
4
10.01.2015
65.47
66.31
60.00
63.93
3.7%
6.1%
YES
5
15.01.2015
58.00
61.56
65.82
61.79
6.5%
6.1%
YES
6
15.01.2015
66.04
63.96
54.13
61.38
7.6%
11.8%
YES
7
15.01.2015
55.51
57.11
54.22
55.61
2.7%
2.5%
YES
8
15.01.2015
65.20
62.71
66.22
64.71
2.3%
3.1%
YES
9
15.01.2015
61.29
55.64
60.13
59.02
3.8%
5.7%
YES
10
15.01.2015
65.20
64.00
59.69
62.96
3.6%
5.2%
YES
11
15.01.2015
61.96
62.40
64.67
63.01
2.6%
1.7%
YES
12
15.01.2015
63.73
56.98
65.07
61.93
5.1%
8.0%
YES
13
16.01.2015
60.67
63.42
67.47
63.85
5.7%
5.0%
YES
14
20.01.2015
58.80
61.47
62.98
61.08
3.1%
3.7%
YES
15
20.01.2015
65.73
61.16
62.58
63.16
4.1%
3.2%
YES
16
21.01.2015
54.49
58.22
60.62
57.78
4.9%
5.7%
YES
17
21.01.2015
57.38
58.71
59.16
58.41
1.3%
1.8%
YES
18
21.01.2015
63.16
54.62
58.27
58.68
7.6%
6.9%
YES
19
21.01.2015
54.89
60.80
55.16
56.95
6.8%
3.6%
YES
20
22.01.2015
60.13
64.00
62.98
62.37
2.6%
3.6%
YES
21
22.01.2015
61.69
62.58
65.82
63.36
3.9%
2.6%
YES
22
24.01.2015
63.87
61.91
60.58
62.12
2.8%
2.5%
YES
23
25.01.2015
63.02
60.62
61.64
61.76
2.0%
1.8%
YES
24
25.01.2015
62.58
68.04
63.51
64.71
5.2%
3.3%
YES
25
27.01.2015
62.04
65.20
65.38
64.21
1.8%
3.4%
YES
26
28.01.2015
65.96
62.89
64.22
64.36
2.5%
2.3%
YES
27
29.01.2015
63.96
65.82
57.51
62.43
5.4%
7.9%
YES
28
05.02.2015
56.22
58.53
63.78
59.51
7.2%
5.5%
YES
29
06.02.2015
56.67
60.49
54.93
57.36
5.4%
4.2%
YES
30
07.02.2015
61.16
57.33
54.09
57.53
6.3%
6.0%
YES
31
10.02.2015
64.49
66.13
61.73
64.12
3.1%
3.7%
YES
32
15.02.2015
57.87
58.84
58.53
58.41
0.7%
0.9%
YES
33
17.02.2015
54.89
54.36
59.60
56.28
5.9%
3.4%
YES
34
17.02.2015
56.53
57.51
59.29
57.78
2.6%
2.2%
YES
35
17.02.2015
56.13
55.42
59.11
56.89
3.9%
2.6%
YES
36
17.02.2015
56.49
56.04
60.36
57.63
4.7%
2.8%
YES
37
17.02.2015
61.16
59.56
57.96
59.56
2.7%
2.7%
YES
38
18.02.2015
59.42
56.67
58.31
58.13
2.2%
2.5%
YES
39
20.02.2015
62.40
56.09
60.18
59.56
4.8%
5.8%
YES
40
23.02.2015
63.29
65.47
56.98
61.91
5.7%
8.0%
YES
41
24.02.2015
55.51
55.02
55.38
55.30
0.4%
0.5%
YES
42
24.02.2015
58.18
61.29
63.11
60.86
3.7%
4.4%
YES
43
25.02.2015
54.98
56.00
55.60
55.53
0.9%
1.0%
YES
44
26.02.2015
63.56
59.07
58.98
60.53
5.0%
2.6%
YES
45
26.02.2015
61.69
63.47
61.47
62.21
2.0%
1.2%
YES
46
26.02.2015
64.31
56.89
61.02
60.74
5.9%
6.3%
YES
47
28.02.2015
60.53
61.73
59.38
60.55
2.0%
1.9%
YES
Analysis of strength achievement %age :
Sl No
Date of Cast
28 day Str.
56 day Str.
%ge at 28 day
WRT fck56
%ge at 56 day
WRT fck56
1
05.01.2015
47.20
65.93
94.4%
132%
2
06.01.2015
49.38
63.69
98.8%
127%
3
08.01.2015
46.55
57.84
93.1%
116%
4
10.01.2015
48.36
63.93
96.7%
128%
5
15.01.2015
50.25
61.79
100.5%
124%
6
15.01.2015
50.24
61.38
100.5%
123%
7
15.01.2015
49.39
55.61
98.8%
111%
8
15.01.2015
49.01
64.71
98.0%
129%
9
15.01.2015
46.43
59.02
92.9%
118%
10
15.01.2015
51.59
62.96
103.2%
126%
11
15.01.2015
49.48
63.01
99.0%
126%
12
15.01.2015
49.17
61.93
98.3%
124%
13
16.01.2015
47.01
63.85
94.0%
128%
14
20.01.2015
47.93
61.08
95.9%
122%
15
20.01.2015
48.76
63.16
97.5%
126%
16
21.01.2015
48.80
57.78
97.6%
116%
17
21.01.2015
49.32
58.41
98.6%
117%
18
21.01.2015
48.71
58.68
97.4%
117%
19
21.01.2015
49.82
56.95
99.6%
114%
20
22.01.2015
45.53
62.37
91.1%
125%
21
22.01.2015
47.93
63.36
95.9%
127%
22
24.01.2015
50.01
62.12
100.0%
124%
23
25.01.2015
54.99
61.76
110.0%
124%
24
25.01.2015
56.04
64.71
112.1%
129%
25
27.01.2015
49.91
64.21
99.8%
128%
26
28.01.2015
48.74
64.36
97.5%
129%
27
29.01.2015
47.67
62.43
95.3%
125%
28
05.02.2015
46.00
59.51
92.0%
119%
29
06.02.2015
46.56
57.36
93.1%
115%
30
07.02.2015
46.64
57.53
93.3%
115%
31
10.02.2015
48.68
64.12
97.4%
128%
32
15.02.2015
47.63
58.41
95.3%
117%
33
17.02.2015
44.64
56.28
89.3%
113%
34
17.02.2015
46.18
57.78
92.4%
116%
35
17.02.2015
45.97
56.89
91.9%
114%
36
17.02.2015
45.67
57.63
91.3%
115%
37
17.02.2015
47.02
59.56
94.0%
119%
38
18.02.2015
44.81
58.13
89.6%
116%
39
20.02.2015
49.16
59.56
98.3%
119%
40
23.02.2015
44.99
61.91
90.0%
124%
41
24.02.2015
42.30
55.30
84.6%
111%
42
24.02.2015
46.47
60.86
92.9%
122%
43
25.02.2015
44.10
55.53
88.2%
111%
44
26.02.2015
48.39
60.53
96.8%
121%
45
26.02.2015
46.83
62.21
93.7%
124%
46
26.02.2015
50.09
60.74
100.2%
121%
47
28.02.2015
45.44
60.55
90.9%
121%
0.00
40.0%
60.0%
10.00
80.0%
20.00
100.0%
30.00
120.0%
40.00
140.0%
50.00
160.0%
60.00
180.0%
70.00
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
Statistical Analysis:
28 day Str.
56 day Str.
%ge at 28 day WRT fck56 (at 2nd axis)
M50 TC
MIX ID:
OPC
FA
SLAG
McSi
Total Binder
213
300
513
BINDER DETAIL:
PERIOD OF CASTING: Report Date:
07/05/2014
01-01-2015 to 28-02-2015
Charac. Strength (fck) : Assumed Std. Deviation: Target Mean Strength (TMS) =
50
5
58.3
Mpa MPa MPa
Serial No.
Date of casting
Avg 56 days Strength (MPa)of each set
(3 cubes)
Conformity to Table:2 (Teat Result >=fck)
Accep-tance Test required or not
Individual test
Group Test
Output
fck – 3
Conformity (56dy str >= fck – 3
3 previous non- overlapping consecutive test results to form a group of 4 results
Avg. of Group
A= fck+0.825*[sd]
B = fck+3
Controlling Value (Max of A & B)
Conformity (Gr.Avg
>= Cont. Val.)
Final Acceptance of Low Result
1
05.01.2015
65.93
OK
NO
–
–
–
–
–
–
–
–
–
–
–
2
06.01.2015
63.69
OK
NO
–
–
–
–
–
–
–
–
–
–
–
3
08.01.2015
57.84
OK
NO
–
–
–
–
–
–
–
–
–
–
–
4
10.01.2015
63.93
OK
NO
–
–
–
–
–
–
–
–
–
–
–
5
15.01.2015
61.79
OK
NO
–
–
–
–
–
–
–
–
–
–
–
6
15.01.2015
61.38
OK
NO
–
–
–
–
–
–
–
–
–
–
–
7
15.01.2015
55.61
OK
NO
–
–
–
–
–
–
–
–
–
–
–
8
15.01.2015
64.71
OK
NO
–
–
–
–
–
–
–
–
–
–
–
9
15.01.2015
59.02
OK
NO
–
–
–
–
–
–
–
–
–
–
–
10
15.01.2015
62.96
OK
NO
–
–
–
–
–
–
–
–
–
–
–
11
15.01.2015
63.01
OK
NO
–
–
–
–
–
–
–
–
–
–
–
12
15.01.2015
61.93
OK
NO
–
–
–
–
–
–
–
–
–
–
–
13
16.01.2015
63.85
OK
NO
–
–
–
–
–
–
–
–
–
–
–
14
20.01.2015
61.08
OK
NO
–
–
–
–
–
–
–
–
–
–
–
15
20.01.2015
63.16
OK
NO
–
–
–
–
–
–
–
–
–
–
–
16
21.01.2015
57.78
OK
NO
–
–
–
–
–
–
–
–
–
–
–
17
21.01.2015
58.41
OK
NO
–
–
–
–
–
–
–
–
–
–
–
18
21.01.2015
58.68
OK
NO
–
–
–
–
–
–
–
–
–
–
–
19
21.01.2015
56.95
OK
NO
–
–
–
–
–
–
–
–
–
–
–
20
22.01.2015
62.37
OK
NO
–
–
–
–
–
–
–
–
–
–
–
21
22.01.2015
63.36
OK
NO
–
–
–
–
–
–
–
–
–
–
–
22
24.01.2015
62.12
OK
NO
–
–
–
–
–
–
–
–
–
–
–
23
25.01.2015
61.76
OK
NO
–
–
–
–
–
–
–
–
–
–
–
24
25.01.2015
64.71
OK
NO
–
–
–
–
–
–
–
–
–
–
–
25
27.01.2015
64.21
OK
NO
–
–
–
–
–
–
–
–
–
–
–
26
28.01.2015
64.36
OK
NO
–
–
–
–
–
–
–
–
–
–
–
27
29.01.2015
62.43
OK
NO
–
–
–
–
–
–
–
–
–
–
–
28
05.02.2015
59.51
OK
NO
–
–
–
–
–
–
–
–
–
–
–
29
06.02.2015
57.36
OK
NO
–
–
–
–
–
–
–
–
–
–
–
30
07.02.2015
57.53
OK
NO
–
–
–
–
–
–
–
–
–
–
–
31
10.02.2015
64.12
OK
NO
–
–
–
–
–
–
–
–
–
–
–
32
15.02.2015
58.41
OK
NO
–
–
–
–
–
–
–
–
–
–
–
33
17.02.2015
56.28
OK
NO
–
–
–
–
–
–
–
–
–
–
–
34
17.02.2015
57.78
OK
NO
–
–
–
–
–
–
–
–
–
–
–
35
17.02.2015
56.89
OK
NO
–
–
–
–
–
–
–
–
–
–
–
36
17.02.2015
57.63
OK
NO
–
–
–
–
–
–
–
–
–
–
–
37
17.02.2015
59.56
OK
NO
–
–
–
–
–
–
–
–
–
–
–
38
18.02.2015
58.13
OK
NO
–
–
–
–
–
–
–
–
–
–
–
39
20.02.2015
59.56
OK
NO
–
–
–
–
–
–
–
–
–
–
–
40
23.02.2015
61.91
OK
NO
–
–
–
–
–
–
–
–
–
–
–
41
24.02.2015
55.30
OK
NO
–
–
–
–
–
–
–
–
–
–
–
42
24.02.2015
60.86
OK
NO
–
–
–
–
–
–
–
–
–
–
–
43
25.02.2015
55.53
OK
NO
–
–
–
–
–
–
–
–
–
–
–
44
26.02.2015
60.53
OK
NO
–
–
–
–
–
–
–
–
–
–
–
45
26.02.2015
62.21
OK
NO
–
–
–
–
–
–
–
–
–
–
–
46
26.02.2015
60.74
OK
NO
–
–
–
–
–
–
–
–
–
–
–
47
28.02.2015
60.55
OK
NO
–
–
–
–
–
–
–
–
–
–
–
Note:-Minimum 30 Test Results are essential to establish Standard Deviation.
Graphical Representation of Analysis:
STRENGTH ANALYSIS
70
STRENGTH (MPa)
60
50
40
30
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
60.58
0.16
0.14
NORMAL DISTRIBUTION
0
5
10
%GE RESULTS WITHIN INTERVAL
42-43
43-44
44-45
45-46
46-47
47-48
48-49
49-50
50-51
51-52
52-53
53-54
54-55
55-56
56-57
57-58
58-59
59-60
60-61
61-62
62-63
63-64
64-65
65-66
66-67
67-68
68-69
69-70
70-71
71-72
SL. NUMBER OF SAMPLES fck f-tr Mean 28d str
15
FREQUENCY DISTRIBUTION (HISTOGRAM)
STRENGTH INTERVAL (MPa)
0.12
0.10
0.08
0.06
0.04
55.86
0.02
0.00
30
35
40
45
50
55
58.3
60
65
70
75
80
85
STRENGTH (MPa)
Actual Mean Conf fck f-tr Target
CONCLUSION:
After analyzing the test result of M50 Temp. Controlled Concrete, cast during Jan 2017 to Feb 2017 (47 Nos.), the compressive strength is changing due to change in weather condition through the months. Which confirm that the compressive strength will effect from the environmental condition while other conditions were controlled.
After analyzing the test results of M50 Temp. Controlled Concrete, cast during Jan 2017 to Feb 2017 (47 nos), it has been found that the concrete conforms to the requirements of the table 2 of IS 456-2000.
Not a single specimen is beyond the deviation limit of 15% from average of three specimens. All the test results are complying with the requirements of Clause 15.4 of IS 456:2000.
Mean of the test results is 60.58 MPa against the Targeted Mean Strength 58.3 MPa. Chances of getting low result than 50 MPa is reported as 0.01% compared to the assumed value of 5% (1 low result in 20).
Established Standard Deviation 2.9 MPa is well below the estimated Standard Deviation 5 MPa (as per IS 456- 2000), which implies an excellent control over the quality of the concrete.
The concrete conforms to the requirements of the agreed criteria for acceptance and Table 11 of IS 456-
2000. Not a single test result is below fck-3 i.e. 47 MPa. All the test results are above fck+3 i.e. 53 MPa.
REFERENCES
-
IS: 269:2015, Ordinary Portland cement Specification.
-
IS: 4031 (Part-2) -1999 (RA 2009), Methods of Physical Tests for Hydraulic Cement. Part-2 Determination of fineness by Blaine Air Permeability Method.
-
IS: 4031 (Part-3 to 6)-1988 (RA 2009), Methods of Physical Tests for Hydraulic Cement. Part-3 Determination of Soundness, Part-4 Determination of consistency of standard cement paste, Part-5 Determination of initial and final setting times, Part-6 Determination of compressive strength of hydraulic cement other than masonry cement.
-
IS: 4032- 1985 (Reaffirmed 2009), Method of chemical analysis of hydraulic cement.
-
IS: 383-2016, Specification for coarse and fine aggregate from natural sources for concrete.
-
IS: 9103-1999 (RA: 2013), Concrete Admixture Specification.
-
IS: 456: 2000 (Reaffirmed 2005), Plain and Reinforced concrete Code of Practice (Fourth Revision) (Tenth Reprint April 2007 including amendments 1 and 2 )
-
IS: 7861 (Part-1)-1975, Code of Practice for Extreme Weather Concreting, Part-I recommended for Hot Weather Concreting.
-
IS: 10262:2009, Concrete Mix Proportioning Guideline (First Revision).
-
ACI-211.1-91, standard practice for selecting proportion for normal, heavyweight and mass concrete (ACI-211.1-91) reapproved 1997.
-