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Daily Digest Mon Oct 18 23:00:03 2004

 
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ibarua
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PostPosted: Tue Oct 19, 2004 2:35 am    Post subject: Daily Digest Mon Oct 18 23:00:03 2004 Reply with quote

19 October, 2004

Re.: Grade 53 cement
---------------
A senior engineer employed by one of our clients had advised me about 10 years ago not to specify or allow the use of grade 53 cement in our works. This was because of some problems faced at the Atomic Energy Project in Mumbai. It sems that a structure where grade 53 cement had been used had developed cracks -- and this became a major problem. I had written to the Cement Research Institute and the ACC for information on the subject, but they both kept quiet. Has anyone got information on the subject?


Re.: Use of fly ash in concrete
--------------------------

I am pleasantly surprised to know that with use of fly ash, cement consumption at 4.5 kg per cu.m. has been achieved for concrete with strength as high as 35 MPA. The savings in cost must be substantial. However, we need to know the long term effects before using such concretes for structural work. The parameters would be durability, shrinkage and creep effects. Shrinkage might not be a problem because the cement content is low, but durabilty and creep effects could perhaps be problems.

Indrajit Barua.

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ibarua
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PostPosted: Tue Oct 19, 2004 2:35 am    Post subject: Daily Digest Mon Oct 18 23:00:03 2004 Reply with quote

19 October, 2004

Re.: Grade 53 cement
---------------
A senior engineer employed by one of our clients had advised me about 10 years ago not to specify or allow the use of grade 53 cement in our works. This was because of some problems faced at the Atomic Energy Project in Mumbai. It sems that a structure where grade 53 cement had been used had developed cracks -- and this became a major problem. I had written to the Cement Research Institute and the ACC for information on the subject, but they both kept quiet. Has anyone got information on the subject?


Re.: Use of fly ash in concrete
--------------------------

I am pleasantly surprised to know that with use of fly ash, cement consumption at 4.5 kg per cu.m. has been achieved for concrete with strength as high as 35 MPA. The savings in cost must be substantial. However, we need to know the long term effects before using such concretes for structural work. The parameters would be durability, shrinkage and creep effects. Shrinkage might not be a problem because the cement content is low, but durabilty and creep effects could perhaps be problems.

Indrajit Barua.

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ibarua
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Joined: 26 Jan 2003
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PostPosted: Tue Oct 19, 2004 2:35 am    Post subject: Daily Digest Mon Oct 18 23:00:03 2004 Reply with quote

19 October, 2004

Re.: Grade 53 cement
---------------
A senior engineer employed by one of our clients had advised me about 10 years ago not to specify or allow the use of grade 53 cement in our works. This was because of some problems faced at the Atomic Energy Project in Mumbai. It sems that a structure where grade 53 cement had been used had developed cracks -- and this became a major problem. I had written to the Cement Research Institute and the ACC for information on the subject, but they both kept quiet. Has anyone got information on the subject?


Re.: Use of fly ash in concrete
--------------------------

I am pleasantly surprised to know that with use of fly ash, cement consumption at 4.5 kg per cu.m. has been achieved for concrete with strength as high as 35 MPA. The savings in cost must be substantial. However, we need to know the long term effects before using such concretes for structural work. The parameters would be durability, shrinkage and creep effects. Shrinkage might not be a problem because the cement content is low, but durabilty and creep effects could perhaps be problems.

Indrajit Barua.

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ibarua
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Joined: 26 Jan 2003
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PostPosted: Tue Oct 19, 2004 2:35 am    Post subject: Daily Digest Mon Oct 18 23:00:03 2004 Reply with quote

19 October, 2004

Re.: Grade 53 cement
---------------
A senior engineer employed by one of our clients had advised me about 10 years ago not to specify or allow the use of grade 53 cement in our works. This was because of some problems faced at the Atomic Energy Project in Mumbai. It sems that a structure where grade 53 cement had been used had developed cracks -- and this became a major problem. I had written to the Cement Research Institute and the ACC for information on the subject, but they both kept quiet. Has anyone got information on the subject?


Re.: Use of fly ash in concrete
--------------------------

I am pleasantly surprised to know that with use of fly ash, cement consumption at 4.5 kg per cu.m. has been achieved for concrete with strength as high as 35 MPA. The savings in cost must be substantial. However, we need to know the long term effects before using such concretes for structural work. The parameters would be durability, shrinkage and creep effects. Shrinkage might not be a problem because the cement content is low, but durabilty and creep effects could perhaps be problems.

Indrajit Barua.

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ibarua
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Joined: 26 Jan 2003
Posts: 1039

PostPosted: Tue Oct 19, 2004 2:35 am    Post subject: Daily Digest Mon Oct 18 23:00:03 2004 Reply with quote

19 October, 2004

Re.: Grade 53 cement
---------------
A senior engineer employed by one of our clients had advised me about 10 years ago not to specify or allow the use of grade 53 cement in our works. This was because of some problems faced at the Atomic Energy Project in Mumbai. It sems that a structure where grade 53 cement had been used had developed cracks -- and this became a major problem. I had written to the Cement Research Institute and the ACC for information on the subject, but they both kept quiet. Has anyone got information on the subject?


Re.: Use of fly ash in concrete
--------------------------

I am pleasantly surprised to know that with use of fly ash, cement consumption at 4.5 kg per cu.m. has been achieved for concrete with strength as high as 35 MPA. The savings in cost must be substantial. However, we need to know the long term effects before using such concretes for structural work. The parameters would be durability, shrinkage and creep effects. Shrinkage might not be a problem because the cement content is low, but durabilty and creep effects could perhaps be problems.

Indrajit Barua.

Posted via Email
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ibarua
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Joined: 26 Jan 2003
Posts: 1039

PostPosted: Tue Oct 19, 2004 2:35 am    Post subject: Daily Digest Mon Oct 18 23:00:03 2004 Reply with quote

19 October, 2004

Re.: Grade 53 cement
---------------
A senior engineer employed by one of our clients had advised me about 10 years ago not to specify or allow the use of grade 53 cement in our works. This was because of some problems faced at the Atomic Energy Project in Mumbai. It sems that a structure where grade 53 cement had been used had developed cracks -- and this became a major problem. I had written to the Cement Research Institute and the ACC for information on the subject, but they both kept quiet. Has anyone got information on the subject?


Re.: Use of fly ash in concrete
--------------------------

I am pleasantly surprised to know that with use of fly ash, cement consumption at 4.5 kg per cu.m. has been achieved for concrete with strength as high as 35 MPA. The savings in cost must be substantial. However, we need to know the long term effects before using such concretes for structural work. The parameters would be durability, shrinkage and creep effects. Shrinkage might not be a problem because the cement content is low, but durabilty and creep effects could perhaps be problems.

Indrajit Barua.

Posted via Email
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ibarua
General Sponsor
General Sponsor


Joined: 26 Jan 2003
Posts: 1039

PostPosted: Tue Oct 19, 2004 2:35 am    Post subject: Daily Digest Mon Oct 18 23:00:03 2004 Reply with quote

19 October, 2004

Re.: Grade 53 cement
---------------
A senior engineer employed by one of our clients had advised me about 10 years ago not to specify or allow the use of grade 53 cement in our works. This was because of some problems faced at the Atomic Energy Project in Mumbai. It sems that a structure where grade 53 cement had been used had developed cracks -- and this became a major problem. I had written to the Cement Research Institute and the ACC for information on the subject, but they both kept quiet. Has anyone got information on the subject?


Re.: Use of fly ash in concrete
--------------------------

I am pleasantly surprised to know that with use of fly ash, cement consumption at 4.5 kg per cu.m. has been achieved for concrete with strength as high as 35 MPA. The savings in cost must be substantial. However, we need to know the long term effects before using such concretes for structural work. The parameters would be durability, shrinkage and creep effects. Shrinkage might not be a problem because the cement content is low, but durabilty and creep effects could perhaps be problems.

Indrajit Barua.

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kalgal_mr
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Joined: 26 Jan 2003
Posts: 9

PostPosted: Tue Oct 19, 2004 8:02 am    Post subject: Daily Digest Mon Oct 18 23:00:03 2004 Reply with quote

Dear SEFIans
This has reference to the use of Puzzolanas in concrete, raised by Mr. Daljit and responded to by Mr. Barua, Mr. Neeraj and Mr. Rajamane. The apprehension about use of Puzzolans is not without valid reasons. But at the same time totally discarding the use of pozzolans is also not right. We need to know what 'aggressive environment' is being talked about. If what Mr. Daljit is talking about is cement with puzzolana being 'blended' at the stage of manufacturing, it can normally be presumed that the cement manufacturers stick to norms in terms of 'quality' and 'quantity' of fly-ash being added. Many a times the failures in performance are not due to the fly-ash, but due to the 'over-confidence (which might have been due to some overzealous marketing person promising the moon) that blended cement can take care of all the mistakes in making good concrete. The reduction in pH, if any, causing higher corrosion potential is, according to me not valid since the quantum of reduction in pH due
to the incorporation of fly-ash(at a level of about 15-20%) is not alarming.
I have been involved with constructions where blended cements from reputed manufacturers has been used for structural concrete without any problem. Durability is a long term issue and as Mr. Rajamane suggests we need to look at the report of CECRI and others before passing sweeping remarks about blended cement. Prof. Kaushik of IIT-Roorkee is very knowledgeable in the field and I expect that we get some clarifications from him.
Regards,
Dr. M. R. Kalgal
Gen. Manager - Tech.,
BBR(India) Ltd


          
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