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In-Situ Testing of Concrete Structure for Durability

 
This forum is locked: you cannot post, reply to, or edit topics.This topic is locked: you cannot edit posts or make replies. Thank Post    www.sefindia.org Forum Index -> E-conference on Durability of Concrete - Feb 27 to March 11 - 2012
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gopal904
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Joined: 11 Aug 2008
Posts: 10
Location: NIT Calicut, Kerala

PostPosted: Thu Mar 01, 2012 6:34 am    Post subject: In-Situ Testing of Concrete Structure for Durability Reply with quote

Dear Sirs,

I have been following all the posts posted on this e-conference. All the talks presented here are very much helpful for us.

Much has been talked about how we can assure durability of the concrete structure while construction, like selection of good quality of aggregates, mixing, transporting, placing and curing etc. Indeed these things if done properly will make the structure highly durable.

I have read in one of the post of Vijay Kulkarni that some of the contractors have started using durability tests for concrete such as water penetration test (DIN 1048), rapid chloride ion permeability test (RCPT), initial surface absorption test (ISAT). For the first time I have heard this type of tests, as I am just like a fresher in this forum not having much experience of the construction.

I would like to know how can we test the durability of the structures like beam, columns, slabs etc? What are different tests available for the same, and what are the procedures, limitations, and acceptance criteria of different tests for durability in different climatic conditions. Kindly mention any relevant codes with it. I wish some of our sefians will take pain for posting details of these tests. This will help not only me, but all the freshers and experienced professionals around the world who will read it.

Thank you,
Gopal Mishra
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Dr. N. Subramanian
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Joined: 21 Feb 2008
Posts: 5295
Location: Gaithersburg, MD, U.S.A.

PostPosted: Thu Mar 01, 2012 4:43 pm    Post subject: Re: In-Situ Testing of Concrete Structure for Durability Reply with quote

Dear Er Gopal,

I am not sure whether IS code has prescribed these tests. My friend Dr Karthik H. Obla working in NRMCA, USA has published an article in Concrete International, May 2007 isse and I am quoting from this.
" Current durability provisions in industry standards rely on a prescriptive water-cementitious material ratio (w/cm) intended to control permeability along with a
specified minimum compressive strength (fck) that serves as an acceptance criterion. Depending on the types and proportions of supplementary cementitious materials and admixtures, however, there can be a large difference in
the permeability of two concrete mixtures with the same w/cm. An alternative to specifying maximum w/cm is to specify performance criteria based on ASTM C 1202-05,3 “Standard Test Method for Electrical Indication of Concrete’s Ability to Resist Chloride Ion Penetration,” commonly referred to as the rapid chloride permeability (RCP) test. While the method has its detractors, it’s perhaps
the only standardized test that provides a reasonably good indicator of concrete permeability in a reasonable amount of time."

Details of RCP test can be had from his paper, which may be downloaded from http://www.nrmca.org/research/ci2905obla.pdf

Poston et al in their paper Condition Assessment using Non-destructive Evaluation, Conc. Int.,Vol. 17, No.7, July 1, 1995, have listed all the modern Non-destructive tests on concrete.

Best wishes
NS


gopal904 wrote:
Dear Sirs,

I have been following all the posts posted on this e-conference. All the talks presented here are very much helpful for us.

Much has been talked about how we can assure durability of the concrete structure while construction, like selection of good quality of aggregates, mixing, transporting, placing and curing etc. Indeed these things if done properly will make the structure highly durable.

I have read in one of the post of Vijay Kulkarni that some of the contractors have started using durability tests for concrete such as water penetration test (DIN 1048), rapid chloride ion permeability test (RCPT), initial surface absorption test (ISAT). For the first time I have heard this type of tests, as I am just like a fresher in this forum not having much experience of the construction.

I would like to know how can we test the durability of the structures like beam, columns, slabs etc? What are different tests available for the same, and what are the procedures, limitations, and acceptance criteria of different tests for durability in different climatic conditions. Kindly mention any relevant codes with it. I wish some of our sefians will take pain for posting details of these tests. This will help not only me, but all the freshers and experienced professionals around the world who will read it.

Thank you,
Gopal Mishra
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asparulekar
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Joined: 28 Apr 2008
Posts: 5

PostPosted: Fri Mar 02, 2012 8:27 pm    Post subject: Re: In-Situ Testing of Concrete Structure for Durability Reply with quote

Dear Mr. Gopal,

Yes. There are very effective durability tests ( mainly RCPT)as mentioned earlier. However, as I understand, all these tests are required to be done in the laboratory on the test specimen like cubes/cylinders , except Initial Surface Absorption test ( ISAT) .Even in ISAT, the equipment is too big and not user-friendly, so as to get some useful results on actual structural members.

There are other factors affecting the durability of actual concrete in the members as compared to the same concrete in the test specimen, like degree of compaction, reinforcement congestion, less cover etc. Hence, it is required to develop a correlation between the measurement of durability parameter ( like say permeability or RCPT result) of concrete specimen with some indirect parameter measures by the test on the element itself.

I think NDT in the form of USPV ( Ultrasonic Pulse Velocity TEst) can be used here in most effective way. The benchmark can be established by carrying out USPV on the same specimens on which RCPT is done. Then, USPV can be repeated on actual members like columns and beams as per the sampling criteria and inferences can be drawn by comparative study. USPV can also establish the uniformity of concrete which is also an important parameter in establishing the durability of a structure as a whole.

USPV can also be complimented by cover meter study to check the actual cover thickness to arrive at conclusions releted to in-situ durability of the structural members.

A S Parulekar
Structural Engineer







gopal904 wrote:
Dear Sirs,

I have been following all the posts posted on this e-conference. All the talks presented here are very much helpful for us.

Much has been talked about how we can assure durability of the concrete structure while construction, like selection of good quality of aggregates, mixing, transporting, placing and curing etc. Indeed these things if done properly will make the structure highly durable.

I have read in one of the post of Vijay Kulkarni that some of the contractors have started using durability tests for concrete such as water penetration test (DIN 1048), rapid chloride ion permeability test (RCPT), initial surface absorption test (ISAT). For the first time I have heard this type of tests, as I am just like a fresher in this forum not having much experience of the construction.

I would like to know how can we test the durability of the structures like beam, columns, slabs etc? What are different tests available for the same, and what are the procedures, limitations, and acceptance criteria of different tests for durability in different climatic conditions. Kindly mention any relevant codes with it. I wish some of our sefians will take pain for posting details of these tests. This will help not only me, but all the freshers and experienced professionals around the world who will read it.

Thank you,
Gopal Mishra
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suraj
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Joined: 17 Apr 2008
Posts: 1980
Location: NCR Faridabad, E mail suraj_engineer@yahoo.co.uk

PostPosted: Wed Mar 07, 2012 5:34 am    Post subject: Concrete Durability Tests Reply with quote

Dear Eng Gopal Misra,
Concrete Durability Tests

  1. It  may be true that in India, durability testing might not be conducted.
  2. But, durability tests nowadays, are certainly conducted in Middle East & Gulf region particularly, on significant concrete heavy structures or structures located on coaster belts.
  3. It has been a practice on all major contracts for last decade to include such performing provisions on FEED & project specificatins to mandate these tests for final approval of hardened concrete, in addition to temperature, air voids, cube strength testing arrangements.
  4. On one project ion Qatar, concrete was not approved even, for concrete spacers properietary manufactured by a German vendor.
  5. We tried to avoid such tests due to declinations by vendor since, they could not understand what was required. Ultimately, consultant forced Alkali Silica Reaction as well as Rapic Chloride Penetration Tests to be conducted.
  6. It is true that SCM is a major component that requires effective & timely curing to achieve desired results. Temperature requires on site QRA management & avoidance of cold joints & particlularly, in hot weather conditions.
  7. Heavy concrete, also requires an excellent QRA management controls. It is unfortunate that even QRA engineers, are not well equipped with engineering requirements.
  8. It is also difficult for engineers  involved with construction execution & construction quality disciplines to write a fine print of method statement that can be effectively used for a good quality compliance. Engineers in a broad sense, require this type of disciplne 'office engineering' training by considering all required constriants. This training should be applied uniformally to all global responsible descipline engineers since, this short fall in practical knowledge exists all over globe. Site team is not communicated adequately, about what activities & their relevant sequences are to be followed with. All pours should be based on approved method statements annexued with specific flow skethes/skethes giving clear indication to foreman & site engineers.
  9. Project engineers, project managers & quality control engineers, must design the management procedures in this regard.
  10. I remember one project in year 1999/2002, 600 KTA Ethylene cracking plant in UAE, where our site carried out about 150000 cum of concrete & 50 % on heavy structures, we developed about 100 method statements for various specific activities. These were examinaed for approval by all parties concreted.
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