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P.K.Mallick General Sponsor
Joined: 14 Dec 2008 Posts: 1099
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Posted: Sun Feb 20, 2011 3:44 pm Post subject: ACCEPTANCE CRITERIA OF CONCRETE |
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Please read the attached document and solve the issues
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vikram.jeet General Sponsor
Joined: 26 Jan 2003 Posts: 3839
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Posted: Mon Feb 21, 2011 7:50 am Post subject: ACCEPTANCE CRITERIA OF CONCRETE |
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Respected PK Mallick sir,
It is encouraging to see your posting on sefi after long gap.
Kindly keep guiding on sefi whenever time permit.
with kind regards
vikramjeet
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P.K.Mallick General Sponsor
Joined: 14 Dec 2008 Posts: 1099
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Posted: Mon Feb 21, 2011 5:31 pm Post subject: |
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No response!!!
_________________ P.K.Mallick
p.k.mallick1962@gmail.com
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Arvind Kumar Jaiswal Gold Sponsor
Joined: 14 Feb 2011 Posts: 48
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Posted: Tue Feb 22, 2011 4:48 am Post subject: |
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P.K.Mallick wrote: | No response!!! |
Dear Er P K Mallick,
I will post response, perhaps tomorrow or day after tomorrow.
with warm regards.
Arvind Jaiswal
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rajmane ...
Joined: 26 Jan 2003 Posts: 161
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Posted: Tue Feb 22, 2011 5:25 am Post subject: ACCEPTANCE CRITERIA OF CONCRETE |
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Tuesday, February 22, 2011<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
Dear all
Sub : ACCEPTANCE CRITERIA OF CONCRETE
Ref : Write up by Dr Mullick
A. We must see Clause 16 for ACCEPTANCE CRITERIA OF CONCRETE. Clause 16.1 deals with Compressive Strength and Clause 16.2 with Flexural Strength. Hence, the strength value of 0.3
N/mm2 appearing in Clause 16.2 should not be used for compressive strength. Hence following para needs modification:
“Hence if we look into Acceptance Criteria from both compressive strength as well as flexural strength point view, it can be concluded that
(a) Mean compressive strength of four consecutive test results must be more than equal to characteristic strength of concrete plus 3N/mm2.
(b) Any test results is not less than specified characteristic strength minus 0.3N/mm2.
B. We must use Clause 16.1 and Table 11 for ACCEPTANCE CRITERIA OF CONCRETE for Compressive Strength. Hence, for M25 grade concrete,
· Individual test result shall not be less than fck-4 i.e. 25-4=21 MPa.
(Col No 3 Table 11 of IS code gives a value of 4 and not 3 in the above computation for M25 grade.)
· Mean compressive strength of four consecutive test results for M25 grade concretes must be more than fck+0.825*characteristic strength or fck + 4 N/mm2
(It would be incorrect to check for 25+3=28 MPa and 25-0.3=24.7, as mentioned in the write up. Col No 2 Table 11 of IS code gives a value of 4 and not 3 in the above computation for M25 grade)
Thanking you
Yours sincerely
<?xml:namespace prefix = v ns = "urn:schemas-microsoft-com:vml" />
N P Rajamane
[Secretary, Indian Concrete Institute, Tamil Nadu Centre, Retired Head, Advanced Materials Laboratory, CSIR-Structural Engineering Research Centre]
Head, Centre for Advanced Concrete research (CACR), University Office Building III Floor, SRM University, Kattankulathur - 603203 (Near Chennai), Tamil Nadu Mob 9840076821,
Email :rajamanenp@yahoo.co.uk
--- On Sun, 20/2/11, P.K.Mallick <forum@sefindia.org> wrote:
Posted via Email
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Dr. N. Subramanian General Sponsor
Joined: 21 Feb 2008 Posts: 5538 Location: Gaithersburg, MD, U.S.A.
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Posted: Tue Feb 22, 2011 3:58 pm Post subject: Re: ACCEPTANCE CRITERIA OF CONCRETE |
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Dear Dr Rajamane,
Happy to note that you have joined as Head of the Centre for Advanced Concrete research (CACR), SRM University, Kattankulathur, Chennai.
I wish you all the best in this new assignment and I am sure with your vast experience and credentials, you will take CACR to greater heights.
Best regards,
Subramanian
rajmane wrote: | Tuesday, February 22, 2011<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
Dear all
Sub : ACCEPTANCE CRITERIA OF CONCRETE
Ref : Write up by Dr Mullick
A. We must see Clause 16 for ACCEPTANCE CRITERIA OF CONCRETE. Clause 16.1 deals with Compressive Strength and Clause 16.2 with Flexural Strength. Hence, the strength value of 0.3
N/mm2 appearing in Clause 16.2 should not be used for compressive strength. Hence following para needs modification:
“Hence if we look into Acceptance Criteria from both compressive strength as well as flexural strength point view, it can be concluded that
(a) Mean compressive strength of four consecutive test results must be more than equal to characteristic strength of concrete plus 3N/mm2.
(b) Any test results is not less than specified characteristic strength minus 0.3N/mm2.
B. We must use Clause 16.1 and Table 11 for ACCEPTANCE CRITERIA OF CONCRETE for Compressive Strength. Hence, for M25 grade concrete,
· Individual test result shall not be less than fck-4 i.e. 25-4=21 MPa.
(Col No 3 Table 11 of IS code gives a value of 4 and not 3 in the above computation for M25 grade.)
· Mean compressive strength of four consecutive test results for M25 grade concretes must be more than fck+0.825*characteristic strength or fck + 4 N/mm2
(It would be incorrect to check for 25+3=28 MPa and 25-0.3=24.7, as mentioned in the write up. Col No 2 Table 11 of IS code gives a value of 4 and not 3 in the above computation for M25 grade)
Thanking you
Yours sincerely
<?xml:namespace prefix = v ns = "urn:schemas-microsoft-com:vml" />
N P Rajamane
[Secretary, Indian Concrete Institute, Tamil Nadu Centre, Retired Head, Advanced Materials Laboratory, CSIR-Structural Engineering Research Centre]
Head, Centre for Advanced Concrete research (CACR), University Office Building III Floor, SRM University, Kattankulathur - 603203 (Near Chennai), Tamil Nadu Mob 9840076821,
Email :rajamanenp@yahoo.co.uk
--- On Sun, 20/2/11, P.K.Mallick <forum@sefindia.org> wrote:
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P.K.Mallick General Sponsor
Joined: 14 Dec 2008 Posts: 1099
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Posted: Tue Feb 22, 2011 4:03 pm Post subject: Re: ACCEPTANCE CRITERIA OF CONCRETE |
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rajmane wrote: | Tuesday, February 22, 2011<xml>
Dear all
Sub : ACCEPTANCE CRITERIA OF CONCRETE
Ref : Write up by Dr Mullick
A. We must see Clause 16 for ACCEPTANCE CRITERIA OF CONCRETE. Clause 16.1 deals with Compressive Strength and Clause 16.2 with Flexural Strength. Hence, the strength value of 0.3
N/mm2 appearing in Clause 16.2 should not be used for compressive strength. Hence following para needs modification:
“Hence if we look into Acceptance Criteria from both compressive strength as well as flexural strength point view, it can be concluded that
(a) Mean compressive strength of four consecutive test results must be more than equal to characteristic strength of concrete plus 3N/mm2.
(b) Any test results is not less than specified characteristic strength minus 0.3N/mm2.
B. We must use Clause 16.1 and Table 11 for ACCEPTANCE CRITERIA OF CONCRETE for Compressive Strength. Hence, for M25 grade concrete,
· Individual test result shall not be less than fck-4 i.e. 25-4=21 MPa.
(Col No 3 Table 11 of IS code gives a value of 4 and not 3 in the above computation for M25 grade.)
· Mean compressive strength of four consecutive test results for M25 grade concretes must be more than fck+0.825*characteristic strength or fck + 4 N/mm2
(It would be incorrect to check for 25+3=28 MPa and 25-0.3=24.7, as mentioned in the write up. Col No 2 Table 11 of IS code gives a value of 4 and not 3 in the above computation for M25 grade)
Thanking you
Yours sincerely
<xml>
N P Rajamane
[Secretary, Indian Concrete Institute, Tamil Nadu Centre, Retired Head, Advanced Materials Laboratory, CSIR-Structural Engineering Research Centre]
Head, Centre for Advanced Concrete research (CACR), University Office Building III Floor, SRM University, Kattankulathur - 603203 (Near Chennai), Tamil Nadu Mob 9840076821,
Email :rajamanenp@yahoo.co.uk
--- On Sun, 20/2/11, P.K.Mallick <forum> wrote:
Posted via Email |
Respected Rajamane Sir,
There is an amendment to IS:456-2000 which says
Substitute "Fck+3" for "Fck+4) against "M-20 and above"
Substitute "Fck-3" for "Fck-4" against "M-20 and above"
Secondly ,kindly do not call me "Dr" as I possess no qualification for that.
Warm Regards.
_________________ P.K.Mallick
p.k.mallick1962@gmail.com
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mks ...
Joined: 27 Dec 2008 Posts: 82 Location: Patna: email mks.b08@gmail.com
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Posted: Tue Feb 22, 2011 6:41 pm Post subject: Re: ACCEPTANCE CRITERIA OF CONCRETE |
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Respected Mallick Sir and Rajmane Sir,
I Agreed with Mallick Sir, that there is an amendment vide amendment No -3 August 2007 to IS:456-2000 which says
Substitute "Fck+3" for "Fck+4) against "M-20 and above"
Substitute "Fck-3" for "Fck-4" against "M-20 and above"
Secondly I also agreed with Rajmane Sir, that We must see Clause 16 for ACCEPTANCE CRITERIA OF CONCRETE. Clause 16.1 deals with Compressive Strength and Clause 16.2 with Flexural Strength. Hence, the strength value of 0.3 N/mm^2
I think there was some error while printing the clause 15.1.1 of IS:456 -2000 which states that “In all cases, the 28 days compressive strength specified in Table–2 shall alone be the criterion for acceptance or rejection of concrete” which has been corrected by adding “in accordance with 16 ” at the end of the clause vide amendment No -3 August 2007 to IS:456-2000
Now the clause should be read as In order to get relatively quicker idea ----------------------------------------------------- In all cases, the 28 days compressive strength specified in Table–2 shall alone be the criterion for acceptance or rejection of concrete in accordance with 16.
The “Non-overlapping” means that the test results of one Group should not be taken in the another Group. For example, if there are 50 nos of test result ie Sl No 01 to 50 for a concrete work. And now if we want to make 5 Groups each consisting 10 test results. Then the Group no 1 should contain those 10 results (say Sl No 01 to 10) and the Group No 2 should not contain the results of Group No 1 (ie Sl No 05 to 15) and so on.
I think the Acceptance Criteria formulated in IS:456- 2000 is simplified Acceptance Criteria and has been formulated keeping in view of developments in this field.
Comments from senior members are highly appreciated.
Mithilesh
P.K.Mallick wrote: | Please read the attached document and solve the issues |
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P.K.Mallick General Sponsor
Joined: 14 Dec 2008 Posts: 1099
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Posted: Thu Feb 24, 2011 3:12 am Post subject: |
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Respected All
I am sincerely looking for a solution. Please spare some time on the issue.
_________________ P.K.Mallick
p.k.mallick1962@gmail.com
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Dr. N. Subramanian General Sponsor
Joined: 21 Feb 2008 Posts: 5538 Location: Gaithersburg, MD, U.S.A.
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Posted: Thu Feb 24, 2011 5:45 am Post subject: Re: ACCEPTANCE CRITERIA OF CONCRETE |
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Dear Er Mithilesh,
Yes. These are indicated in the Amendment. Hence I hope that the doubts of Er Mallick are clarified as "In all cases, the 28 days compressive strength specified in Table–2 shall alone be the criterion for acceptance or rejection of concrete in accordance with 16"
Regards,
Subramanian
mks wrote: | Respected Mallick Sir and Rajmane Sir,
I Agreed with Mallick Sir, that there is an amendment vide amendment No -3 August 2007 to IS:456-2000 which says
Substitute "Fck+3" for "Fck+4) against "M-20 and above"
Substitute "Fck-3" for "Fck-4" against "M-20 and above"
Secondly I also agreed with Rajmane Sir, that We must see Clause 16 for ACCEPTANCE CRITERIA OF CONCRETE. Clause 16.1 deals with Compressive Strength and Clause 16.2 with Flexural Strength. Hence, the strength value of 0.3 N/mm^2
I think there was some error while printing the clause 15.1.1 of IS:456 -2000 which states that “In all cases, the 28 days compressive strength specified in Table–2 shall alone be the criterion for acceptance or rejection of concrete” which has been corrected by adding “in accordance with 16 ” at the end of the clause vide amendment No -3 August 2007 to IS:456-2000
Now the clause should be read as In order to get relatively quicker idea ----------------------------------------------------- In all cases, the 28 days compressive strength specified in Table–2 shall alone be the criterion for acceptance or rejection of concrete in accordance with 16.
The “Non-overlapping” means that the test results of one Group should not be taken in the another Group. For example, if there are 50 nos of test result ie Sl No 01 to 50 for a concrete work. And now if we want to make 5 Groups each consisting 10 test results. Then the Group no 1 should contain those 10 results (say Sl No 01 to 10) and the Group No 2 should not contain the results of Group No 1 (ie Sl No 05 to 15) and so on.
I think the Acceptance Criteria formulated in IS:456- 2000 is simplified Acceptance Criteria and has been formulated keeping in view of developments in this field.
Comments from senior members are highly appreciated.
Mithilesh
P.K.Mallick wrote: | Please read the attached document and solve the issues |
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