FORM 2
TH PATENT ACT, 1970
(39 OF 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION (See section 10 and rule 13)
TITLE OF THE INVENTION
A composition for coloured cement and a method of preparing the same.
APPLICANTS
Aditya Birla Science and Technology Company Pvt Ltd, Aditya Birla Centre, 2nd Floor, ‘C’ wing, S. K. Ahire Marg, Worli, Mumbai 400030, Maharashtra, India.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes this invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
[001] The present invention relates to a composition for coloured cement. Moreover, the invention relates to a method of preparing a coloured cement composition using natural dyes.
BACKGROUND OF THE INVENTION
[002] It is desirable to colour exposed cement or concrete surfaces for both aesthetic and functional reasons. Cement can be colored in a variety of ways such as using acid staining, dyes, colored aggregates, cement and integral pigments. Colouring the exposed surface by painting is known. However, painting is an additional step in construction which adds cost and complexity to a construction project. Moreover, an exterior painted surface may require repainting in a relatively short period of time.
[003] Another approach is to add a colour additive to the building material, thereby eliminating the extra step associated with painting the building surface. Coloured cements are made by grinding 5 to 10 percent of suitable pigments with white or grey ordinary portland cement. These pigments are usually metal oxide pigments or synthetic pigments which are not environmentally friendly.
[004] Moreover, any colour additive must be uniformly dispersed throughout the building material. This can be difficult given the low intensity mixing and short mixing times customary in the building materials industry. Moreover, the additive must not adversely affect the desirable properties of the building material such as the strength or setting behaviour of concrete or reduce the compressive strength.

[005] Inorganic pigments are typically used as colour additives for building materials and typically include oxides (natural and synthetic). However, these inorganic pigments offer a limited range of colours and brightness. Additionally, apart from adding colour, oxides do not provide any other additional property to the building materials. Moreover, dry pigment powders have also been used to colour cement or concrete compositions because they are highly dispersible. However, these powders have poor processing properties, and typically cake together and form lumps upon storage.
[006] Lastly, it is not uncommon to find algae or fungus growing on cement or concrete surfaces during wet and humid weather conditions. Green algae will begin to grow on cement or concrete when the surface stays constantly damp. Many homes in humid climates are constantly battling algae and fungus growth. If left untreated, it can permanently discolor the cement or concrete. In addition, algae growth is rather slippery and will become a safety hazard when it is allowed to grow on walkways.
[007] Therefore, there is a need of a composition for coloured cement which solves some of the problems present in the prior art as mentioned above.
SUMMARY OF THE INVENTION
[008] According to an embodiment of the present invention, there is provided a coloured cement composition comprising white cement and up to 1% of natural colorants, both mixed in water, wherein said natural colorants provide color and a retardation effect to the cement composition resulting in delay in final setting time.
[009] According to another embodiment of the present invention, there is provided a coloured cement composition comprising a dry mixture of cement and up to 1% of natural colorants,

wherein upon addition of water to said dry mixture the natural colorants provide color and a retardation effect to the cement composition resulting in delay in final setting time.
[010] A coloured cement composition comprising white cement and up to 1% of powdered turmeric, both mixed in water, wherein said powdered turmeric provides yellow colour to the cement composition.
[011] A coloured cement composition comprising white cement and up to 1% of powdered neem, both mixed in water, wherein said powdered neem provides green colour to the cement composition.
BRIEF DESCRIPTION OF THE DRAWINGS
[012] Figure 1 illustrates the heat of hydration of various mixes measured using isothermal calorimetry.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[013] Accordingly, there is provided a composition for making coloured cement by blending natural colouring materials in it. The natural colouring materials can be either edible or non-edible materials.
[014] According to the embodiments of the present invention, there is provided a coloured cement composition comprising white cement and up to 1% of natural colorants, both mixed in water. These natural colorants provide color and a retardation effect to the cement composition resulting in delay in final setting time.
[015] Depending upon the colour to be imparted to the cementitious composition, the natural colouring materials can be added either separately or in a combination in pre-determined

quantities. It is observed that the addition of natural colouring materials in the cementitious composition results in a shade which stays for a longer duration and does not wear off easily.
[016] According to an embodiment, a coloured cement composition comprising white cement and up to 1% of powdered turmeric, both mixed in water, wherein said powdered turmeric provides yellow colour to the cement composition. Turmeric acts as a retarder and shows good retarding properties in the cementitious composition and therefore its use in a warm weather, where quick setting is a practical problem, can be beneficial.
[017] In an embodiment, a coloured cement composition comprising white cement and up to 1% of powdered neem, both mixed in water, wherein said powdered neem provides green colour to the cement composition.
[018] In an embodiment, the naturally occurring colorant can be selected from a group consisting of turmeric, neem, powdered chick peas, mint leaves, other edible leaves, non-edible leaves, vegetables, ripened fruits, un-ripened fruits, ground ginger, dried tomato powder, ground sandalwood, powdered wheat, powdered rice, chilli powder and combinations thereof. Usage of all these alternatives of natural colouring materials are considered to be within the scope of the present invention.
[019] In an embodiment, turmeric or neem or the likes impart strong anti-microbial properties to the cementitious composition.
[020] Cement reacts with water to give hydration products which are responsible for development of its mechanical properties and also govern the setting times. This reaction is an exothermic process, i.e. it emits heat as a function of time of hydration. Measurement of this heat of hydration is a well-established analytical tool to assess various aspects of reaction kinetics. Usually it is

measured with the help of a calorimeter, which plots amount of heat generated on y-axis and the time on x-axis. A general thumb rule is more the amount of heat given faster is the rate of reaction of cement and shorter the time of setting. If relatively lesser amount of heat is liberated during reaction, it means cement is reacting relatively slowly with water and therefore the setting time will be extended. It can be seen in Figure 1 that the main peak of pure white cement (green colour) which occurs between 2 and 4 hours is tallest. The peak of cement and 1% neem (red colour) in the same time frame is the shortest of the lot, suggesting strongest retardation among the various mixes. In fact, the hydration is retarded to such an extent that it’s at about 20 hours that cement liberates maximum amount of heat – that is a significant delay in the hydration of cement with 1% neem.
[021] In an embodiment, the natural colouring materials can be used in both grey as well as white cement compositions. Preferably, the natural colouring materials can be used to make any cement based products such as mortar, concrete, ready-mix-concrete (RMC), etc. and can be used for 3D printing technique as well.
[022] In an embodiment, the natural colouring material is added to the cement composition in a powdered or liquid form.
[023] Experimental Data:
Advantages and benefits of the embodiments of the present invention would become more apparent from the below experimental details to a person skilled in the art.

[024] Example 1
Determination of consistency of cement paste: The apparatus used was vicat apparatus conforming to IS 5513-1976 for finding the consistency of the cement paste. The consistency of a cement paste was defined as the consistency which permitted the vicat plunger of dimensions 10 mm dia and 50 mm length to penetrate to a point 5 to 7 mm from the bottom of the vicat mould. The cement paste was prepared with 1000 grams of cement and weighed quantity of distilled water. The mixing of cement paste was done using Hobart mixer at constant rotational speed of 285 ± 10 rpm and planetary speed 125 ± 10 rpm, and mixing time of five minutes. The cement paste was then filled into the vicat mould with a non-porous resting plate at the bottom of the mould. After complete filling of the mould with the paste, the mould was slightly shaken to expel any trapped air. The top surface of cement paste was smoothened and made to level with the top surface of the mould. The test block (vicat mould and the non-porous resting plate) was placed under the vicat apparatus rod bearing the plunger. The plunger was lowered gently to touch the top surface of the cement paste and then released quickly. The depth of penetration by the plunger was noted. Trial mixes were done with different percentages of water until the reading was 5 to 7 mm from the bottom of the mould. The lab tests were maintained at temperature 25 ± 5 C and relative humidity 65 ± 5 %. The consistency of white cement, turmeric cement (cement with 0.5 % and 1 % percentage of turmeric powder), neem cement (Cement with 0.5% and 1 % neem powder) is given below:
Table 1: Consistency of various mixes

Mix Consistency – water as
percentage of Mix by
weight
Control (White cement) 29.0

Cement and 0.5% Natural Turmeric 30.5
Cement and 1% Natural Turmeric 31.0
Cement and 0.5% Neem 30.5
Cement and 1.0% Neem 31.0
[025] Determination of Setting time: Initial setting time is the time between when water is added to cement and the time at which 1 mm square needle fails to pierce the test block to a point 5 ± 0.5 mm measured from the bottom of the mould.
Final setting time is the time elapsed between when water is added to cement and time at which when needle with annular attachment is gently placed on the test block the needle makes an impression whereas the annular attachment fails to do.
(a) A cement paste was prepared with 1000 grams of cement mix and water added was 0.85 times the water required for consistency of the mix (Table -1). The mixing of cement paste was done using Hobart mixer.
(b) The cement paste was then filled into the vicat mould with a non-porous resting plate at the bottom of the mould. After complete filling of the mould with the paste, the mould was slightly shaken to expel the air.
(c) The top surface of cement paste was smoothened and made it level with the top surface of the mould. The mould along with the non-porous resting plate was placed under the vicat apparatus rod bearing the needle. The needle was lowered gently to touch the top surface of the cement paste and then released quickly.
(d) The lab tests were maintained at temperature 25 ± 5 °C and relative humidity 65 ± 5%. The setting time results of white cement, turmeric cement (cement with 0.5% and 1% percentage of turmeric powder), neem cement (Cement with 0.5% and 1% neem powder) is given below:

Table 1: Setting times of various mixes

Mix Initial setting time (min) Final setting time (min)
Control (White cement) 70 210
Cement and 0.5% Natural Turmeric 80 210
Cement and 1% Natural Turmeric 90 245
Cement and 0.5% Natural Neem 85 240
Cement and 1.0% Natural Neem 85 420
Example 2:
[026] A detailed study was carried out to check the performance of the colorant material versus the identified chemical in the colorant material that may cause retardation. The summary of test results is as below:
Table 2

Quantity Cement (g) Turmeric (g) Starch (g) Total
weight of dry sample (g) Consistency (%) Initial
setting time (min) Final
setting time (min)
Cement and 1% natural turmeric 1000 10 0 1010 28.5 160 420
Cement
and
starch 1004.5 0 5.5 1010 29.5 160 Not set till 510 mins
Cement
and
starch 1000 0 5.5 1005.5 29.5 176 Not set till 510 mins
[027] Turmeric: It was identified that starch that is present in turmeric to be a possible component that causes retardation. Chemical analysis of turmeric shows it has 55% starch. So an experiment was done wherein cement and 1% turmeric was tested for setting time. Cement was 1000 gm and

turmeric 10 gm (control). 10 gm turmeric will have 55% of 10 gm = 5.5 gm starch. In next experiment, 1004.5 gm cement and 5.5 gm starch was added to keep the total weight of the dry mass as 1010 gm. In another experiment, 1000 gm cement (same as control) and 5.5 gm starch was added.
[028] Neem: It was observed that while the acids present in neem are known retarders, chemicals like calcium present in neem is known to be an accelerator in the form of calcium chloride or calcium hydroxide. Further, the effect of Vitamin C, Carotene etc. which is present in neem is not known. So, the net effect of all these chemicals in neem was observed to give a retardation effect in cement.
[029] Therefore, from the experimental trials, it was observed that not only turmeric and neem imparts colour to the cement composition but are also responsible in providing retardation effect.
[030] The foregoing description of specific embodiments of the present invention has been presented for purposes of description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obvious modifications and variations are possible in light of the above teaching.

We Claim:
1. A coloured cement composition comprising white cement and up to 1% of natural colorants, both mixed in water, wherein said natural colorants provide color and a retardation effect to the cement composition resulting in delay in final setting time.
2. The composition as claimed in claim 1, wherein the naturally occurring colorants can be selected from a group consisting of turmeric, neem, powdered chick peas, mint leaves, other edible leaves, non-edible leaves, vegetables, ripened fruits, un-ripened fruits, ground ginger, dried tomato powder, ground sandalwood, powdered wheat, powdered rice, chilli powder and combinations thereof.
3. A coloured cement composition comprising a dry mixture of cement and up to 1% of natural colorants, wherein upon addition of water to said dry mixture the natural colorants provide color and a retardation effect to the cement composition resulting in delay in final setting time.
4. The composition as claimed in claim 3, wherein the naturally occurring colorants can be selected from a group consisting of turmeric, neem, powdered chick peas, mint leaves, other edible leaves, non-edible leaves, vegetables, ripened fruits, un-ripened fruits, ground ginger, dried tomato powder, ground sandalwood, powdered wheat, powdered rice, chilli powder and combinations thereof.
5. A coloured cement composition comprising white cement and up to 1% of powdered turmeric, both mixed in water, wherein said powdered turmeric provides yellow colour to the cement composition.
6. The composition as claimed in claim 3, wherein the composition has anti-microbial properties.

7. A coloured cement composition comprising white cement and up to 1% of powdered neem, both mixed in water, wherein said powdered neem provides green colour to the cement composition.
8. The composition as claimed in claim 5, wherein the composition has anti-microbial properties.