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SATISH MADHAVRAO KULKARNI SEFI Member
Joined: 10 Feb 2010 Posts: 17
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Posted: Sat Mar 10, 2012 5:11 am Post subject: Alternatives to early strength cements for controlling Cr |
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Dear All,It is true that Fineness requirement for various Cement Grades
is same , i.e. when tested for fineness by
Blaine’s air permeability method as described in IS 4031 ( Part 2 ) : 1988, the specific surface of cement shall not be
less than 225 m’/kg. This is one of the requirements of Physical Properties of Cement.
Even the Soundness requirements are same for 33,43,and 53 Grade Cements.
The important part is the Compressive Strength of cement after at @72 hrs, 168 hrs and 672 hrs.(i.e after 3, 7 and 28 days) The strength at these stages are for 33 grade 16,22,33 MPa, for 43 Grade cement it is 23,33,43,MPa and for 53 Grade cement it is 27,37,53,MPa. It is also precisely mentioned in the codes that there should be continuous increment in the strength after 72 hrs. This just for information.Cement is not judged only by its fineness.
Dr. S. M. Kulkarni
On Sat, Mar 10, 2012 at 6:35 AM, tsriharivaishu <forum@sefindia.org (forum@sefindia.org)> wrote:
Quote: | Dear all,please explain the reasons for using 43 grade cement for concrete with slip form...Sent from BlackBerry® on Airtel
From: tsrihari11@gmail.com (tsrihari11@gmail.com)
Date: Fri, 9 Mar 2012 19:12:12 +0000
To:
ReplyTo: tsrihari11@gmail.com (tsrihari11@gmail.com)
Subject: Re: [ECONF] Re: Alternatives to early strength cements for controlling Cr
Dear sir,when it is conforming to 33 grade cement,then there should not be any problem even if we use for mass concrete...Sent from BlackBerry® on Airtel
From: "abhio"
Date: Sat, 03 Mar 2012 11:40:36 +0530
To:
ReplyTo: econf@sefindia.org (econf@sefindia.org)
Subject: [ECONF] Re: Alternatives to early strength cements for controlling Cr
Please correct me if I am mistaken, but as far as I know, IS: 269, IS: 8112 and IS: 12269 specify only the MINIMUM fineness of cement. This allows cement manufacturers to pack the same cement as 33, 43 or 53 grade as per their discretion and demand. This is particularly unfortunate for projects where large concrete pours are required for massive structures where we would like to have slow setting times with gradual evolution of heat of hydration.
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