Title of Invention

AN ADDITIVE FOR USE IN ORDINARY PORTLAND CEMENT CAPABLE OF REPLACING ORDINARY PORTLAND CEMENT

Abstract This invention relates to an additive for use in ordinary portland cement capable of replacing upto 30% of ordinary portland cement comprising flyash and at least a plasticizer and further this invention relates to a process for the preparation of an additive for use in ordinary portland cement and capable of replacing upto 30% of ordinary portland cement comprising in the steps of introducing flyash into a blender, adding at least a plasticizer thereto and ensuring a proper blending said polymer being added in a amount of 0.25 to 0.5% by weight of fly ash.
Full Text -2-
FIELD OF INVENTION
This invention relates to an additive for use in ordinary portland cement.
The additive of the present invention constitutes a part replacement of
ordinary portland cement.
BACKGROUND OF INVENTION
It is generally known that ash can be generated from coal, and the ash
normally comprises a hard coal ash. Hard coal ash also consists of two
portions, namely a first portion of lighter particles and taken out in a dry
form through electrostate precipitators. Such a portion is normally the
major portion and may comprise in as much as 80% of the flyash. The
other portion comes from the bottom of the furnace and is referred to as
slag or bottom ash and consists of bigger particles.
Yet another ash known in the art is generated from wood and has
different chemical constituents to that of fly ash generated from furnaces
or boilers.
The ash used in the present invention is flyash from furnaces or boilers.

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Fly ash, a by-product of the combustion of pulverized coal was hitherto
considered as a waste material but having excellent pozzolanic
properties. This pozzolanic property of fly ash has been utilized for quite
some time in construction activities such as ready mix concrete.
OBJECTS OF THE INVENTION
An object of this invention is to propose an additive for use in ordinary
Portland cement.
Another object of this invention is to propose an additive for use in
ordinary portland cement which provides an increase in strength by 25
to 30% beyond 28 days of curing at low cost.
Still another object of this invention is to propose an additive for use in
ordinary portland cement which lowers the initial curing time and hence
reduces the de-shuttering time
Yet another object of this invention is to propose an additive for use in
ordinary portland cement which utilizes the waste fly ash of power plant
for a more useful purpose.
A further object of this invention is to propose an additive for use in
ordinary portland cement which is efficient.
Further objects and advantages of this invention be more apparent from
the ensuing description.

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DETAILED DESCRIPTION OF INVENTION
According to this invention there is provided an additive for use in
ordinary portland cement capable of replacing upto 30% of ordinary
Portland cement comprising flyash and at least a plasticizer.
Further, according to this invention there is provided a process for the
preparation of an additive for use in ordinary portland cement and
capable of replacing upto 30% of ordinary portland cement which
comprises in the steps of:
1.) introducing flyash into a blender
2) adding at least a plasticizer thereto and ensuring a proper blending
3) said polymer being added in an amount of 0.25 to 0.5% by weight
of fly ash.
In accordance with this invention, a dry powder form of flyash is added
as an admixture to ordinary portland cement in conjunction with a super
plasticizer. If flyash and super platicizer is added separately to ordinary
portland cement, the required results are not achieved. Thus, flyash and
super plasticizer is added in the form of an admixture, which has
synergism.

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The flyash is introduced into a blender, such as a ribbon blender, and
the plasticizer is added thereto in incremental doses. The quantity of
each dose is not of importance, as such as introduction in dose form is
only to ensure a proper blending of the plasticizer with flyash. The
admixture contains 0.25 to 0.5% by weight of plasticizer to that of flyash.
The plasticizer comprises a sulphonic based polymer, such as napthaline
sulphonatic based polymer. The admixture may by way of another
embodiment also contains 0 to 0.75 of red oxide by weight of flyash.
The function of red oxide is limited only to impart a colour.
The blending is carried out for a period 30 to 60 minutes. During the
process of blending the temperature rises which is responsible for the
synergism effect of the admixture.
The fly ash used in the additive conforms to IS: 3812-2003 which
underlines the limiting value for some specific parameters such as: Loss
on ignition: 5.0% (Max); Fineness: 3200 cm2/gm (Min.) Lime reactivity:
45Kg/cm2 (Min.) etc.) of fly ash to be used for mixing with Ordinary
Portland Cement (OPC). Laboratory test indicates that when fly ash alone
is mixed with OPC early strength of 3 and 7 days is lower than the
strength of OPC alone. To improve upon the strength of 3 and

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7 days chemical admixtures arc to be added in fly ash. For this purpose,
admixtures (super plasticizers) in powder form is developed for making
homogenous mixture with fly ash. Fly ash used is of ASTM class F type.
The studies were conducted on M-25 and M-30 grade concrete cubes of
1) plain OPC 2) plain OPC replaced with 40% fly ash 3) OPC replaced
with varying percentages of developed product. All these cubes were
tested for compressive strength as per India standard. Optimization
study of product mix with OPC were carried out and found that strength
in 3,7,28 and 90 days is increased when 20-30% of OPC is replaced with
product and conforms to be cement standard.
The advantages of the present invention will be apparent from the
various examples as representated in Table 1.

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It is to be noted that the present invention is susceptible to
modifications, adaptations and changes by those skilled in the art. Such
variant embodiments employing the concepts and features of this
invention are intended to be within the scope of the present invention,
which is further set forth under the following claims:-

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We Claim:
1. An additive for use in ordinary portland cement capable of
replacing upto 30% of ordinary portland cement comprising flyash
and at least a plasticizer.
2. An additive as claimed in claim 1 wherein said plasticizer is a
sulphuric based polymer and preferably naphthalene sulphonatc
based polymer.
3. An additive as claimed in claim 1 wherein said admixture is
present in an amount of 0.25 to 0.5% by not.
4. An additive as claimed in claim 1 substantially as herein
described.
5. A process for the preparation of an additive for use in ordinary
portland cement and capable of replacing upto 30% of ordinary
portland cement comprising in the steps of:

1) introducing flyash into a blender
2) adding at least a plasticizer thereto and ensuring a proper
blending
3) said polymer being added in an amount of 0.25 to 0.5% by
weight of fly ash.

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6) A process as claimed in claim 5 wherein said plasticizer is a
sulphuric based polymer and preferably naphthalene sulphonate
based polymer.
7) A process as claimed in claim 5 wherein said admixture is added
in dose form to said fly ash.

This invention relates to an additive for use in ordinary portland cement
capable of replacing upto 30% of ordinary portland cement comprising
flyash and at least a plasticizer and further this invention relates to a
process for the preparation of an additive for use in ordinary portland
cement and capable of replacing upto 30% of ordinary portland cement
comprising in the steps of introducing flyash into a blender, adding at
least a plasticizer thereto and ensuring a proper blending said polymer
being added in a amount of 0.25 to 0.5% by weight of fly ash.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=NIX8rKIeE3buH7Mgv5M9Ew==&loc=wDBSZCsAt7zoiVrqcFJsRw==


Patent Number 270378
Indian Patent Application Number 1163/KOL/2007
PG Journal Number 51/2015
Publication Date 18-Dec-2015
Grant Date 16-Dec-2015
Date of Filing 23-Aug-2007
Name of Patentee NTPC LIMITED
Applicant Address 7B PRETORIA STREET, 3RD & 4TH FLOOR, KOLKATA.
Inventors:
# Inventor's Name Inventor's Address
1 ANIL KUMAR NTPC LIMITED, 7B PRETORIA STREET, 3RD & 4TH FLOOR, KOLKATA.
2 ASHWINI K SINHA NTPC LIMITED, 7B PRETORIA STREET, 3RD & 4TH FLOOR, KOLKATA
3 RAVISH. C. JAIN NTPC LIMITED, 7B PRETORIA STREET, 3RD & 4TH FLOOR, KOLKATA.
4 JAI. KRISHNA. MATHPAL NTPC LIMITED, 7B PRETORIA STREET, 3RD & 4TH FLOOR, KOLKATA.
5 KRISHNAN KANNAN NTPC LIMITED, 7B PRETORIA STREET, 3RD & 4TH FLOOR, KOLKATA
PCT International Classification Number C04B7/42
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA