CLIAMS:1. A modified cement composition comprising:
a. cement in an amount ranging from 50 % to 90 % of the total mass of the composition;
b. asbestos fibers in an amount ranging from 1 % to 10 % of the total mass of the composition; and
c. modified polyester fibers in an amount ranging from 0.1 % to 1.0 % of the total mass of the composition,
wherein said modified polyester fibers are polyester fibers modified with at least one surface modifying agent selected from the group consisting of styrene-acrylate co-polymers, styrene-butadiene polymers, acrylate homo-polymers, vinyl acetate polymers, vinyl acetate co-polymers, styrene-butadiene co-polymers, vinyl acetate emulsions, acrylic emulsions, non-ionic surfactant fatty alcohol ethoxylates, water soluble epoxides and organomodifed silicones and silanes.
2. The composition as claimed in claim 1, further includes fly ash in an amount ranging from 25 % to 45 % of the total mass of the composition.
3. The composition as claimed in claim 1, further includes wood pulp in an amount ranging from 0.1 % to 10.0 % of the total mass of the composition.
4. The composition as claimed in claim 1, further includes water.
5. The composition as claimed in claim 1, wherein said polyester fiber is at least one selected from the group consisting of polyethylene terephthalate (PET), polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polytrimethylene napthalate (PTN), polybutylene naphthalate (PBN), polyethylene naphthalate (PEN) and vectran.
6. The composition as claimed in claim 1, wherein said polyester fiber is recycled polyester.
7. The composition as claimed in claim 1, wherein said styrene-acrylate copolymer is at least one selected from the group consisting of styrene-butyl acrylate copolymer and styrene ethyl acrylate copolymer.
8. The composition as claimed in claim 1, wherein said water soluble epoxide is at least one selected from the group consisting of glycerol epoxide and sorbitol epoxide.
9. An article prepared from the modified cement composition as claimed in claim 1, characterized by flexural strength of at least 97 kg/ cm2, wherein said article is selected from the group consisting of boards, slabs, and sheets.
10. A process for the preparation of an article composed of fibers and cement; said process comprising the following steps:
a. preparing a modified cement composition by admixing cement in an amount ranging from 50 % to 90 % of the total mass of the composition, asbestos fibers in an amount ranging from 1 % to 10 % of the total mass of the composition, modified polyester fibers in an amount ranging from 0.1 % to 1.0 % of the total mass of the composition in the presence of water, optionally, fly ash in an amount ranging from 25 % to 45 % of the total mass of the composition and optionally, wood pulp in an amount ranging from 0.1 % to 10.0 % of the total mass of the composition, in any order;
b. molding said modified cement composition to obtain a molded article; and
c. air curing said molded article to obtain an article,
wherein said article is characterized by flexural strength of at least 97 kg /cm2 and is at least one selected from the group consisting of boards, slabs, and sheets.
11. The process as claimed in claim 10, wherein the step of air curing said molded article is carried out for a time period ranging from 20- 28 days.
12. The process as claimed in claim 10, wherein said modified polyester fibers are polyester fibers modified with at least one surface modifying agent selected from the group consisting of styrene-acrylate co-polymers, styrene-butadiene polymers, acrylate homo-polymers, vinyl acetate polymers, vinyl acetate co-polymers, styrene-butadiene co-polymers, vinyl acetate emulsions, acrylic emulsions, non-ionic surfactant fatty alcohol ethoxylates, water soluble epoxides and organomodifed silicones and silanes.
13. The process as claimed in claim 12, wherein said polyester fiber is at least one selected from the group consisting of polyethylene terephthalate (PET), polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polytrimethylene napthalate (PTN), polybutylene naphthalate (PBN), polyethylene naphthalate (PEN) and vectran.
14. The process as claimed in claim 12, wherein said styrene-acrylate copolymer is at least one selected from the group consisting of styrene-butyl acrylate copolymer and styrene ethyl acrylate copolymer.
15. The process as claimed in claim 12, wherein said water soluble epoxide is at least one selected from the group consisting of glycerol epoxide and sorbitol epoxide. ,TagSPECI:FIELD OF THE DISCLOSURE
The present disclosure relates to cement compositions. Particularly, the present disclosure relates to a modified cement composition and preparation.

BACKGROUND
Compositions that are used as construction material contain cementitious substances as the chief ingredient. The inherent ability of cement to bind different substances together makes it a desirable raw material. Along with cement, various other substances have been explored for use in preparing compositions for construction material such as asbestos, cellophane, cotton seed hulls, vegetable fibers, asphalt, silica fume, rice husk ash, slate, sand, steel, microconcrete, clay and metal, to yield articles such as columns and plinths that have improved durability, load bearing and abrasion resistance. However, the health risks associated with the use of asbestos have resulted in a ban on its use beyond threshold values in most of the countries.
Efforts are, therefore, being directed towards developing compositions that contain less amounts of asbestos or different asbestos substituents. US5637144 recites the use of water retention agents and metal clays, which when used in pre-determined proportions, yield properties analogous to those of asbestos when used in cement-mortar compositions. US4302370 describes a composition comprising polyolefin fibers blended with asphalt cutback along with propylene carbonate as a coupling agent. The compositions of the afore-stated patents, however, contain significant quantities of asphalt which, in excess, causes various health hazards such as headache, skin rash, sensitization, fatigue, reduced appetite, throat and eye irritation, cough and skin cancer, in addition to posing a significant threat to the environment.
The inventors of the present disclosure have provided a modified fiber-cement composition and a process for its preparation that mitigates most of the disadvantages associated with the known compositions and their processes of preparation.

OBJECTS
Some of the objects of the present disclosure, of which at least one embodiment is adapted to provide, are described herein below:
It is an object of the present disclosure to provide a modified cement composition.
It is another object of the present disclosure to provide a modified cement composition, which is environment friendly and has wide industrial applications.
It is still another object of the present disclosure to provide a process for the preparation of a modified cement composition.
It is yet another object of the present disclosure to provide a process for the preparation of a modified cement composition, which is simple and cost effective.
It is still another object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
Other objects and advantages of the present disclosure will be more apparent from the following description which is not intended to limit the scope of the present disclosure.

SUMMARY
The present disclosure provides a modified cement composition comprising:
a. cement in an amount ranging from 50 % to 90 % of the total mass of the composition;
b. asbestos fibers in an amount ranging from 1 % to 10 % of the total mass of the composition; and
c. modified polyester fibers in an amount ranging from 0.1 % to 1.0 % of the total mass of the composition,
wherein said modified polyester fibers are polyester fibers modified with at least one surface modifying agent selected from the group consisting of styrene-acrylate co-polymers, styrene-butadiene polymers, acrylate homo-polymers, vinyl acetate polymers, vinyl acetate co-polymers, styrene-butadiene co-polymers, vinyl acetate emulsions, acrylic emulsions, non-ionic surfactant fatty alcohol ethoxylates, water soluble epoxides and organomodifed silicones and silanes.
The composition of the present disclosure further includes fly ash in an amount ranging from 25 % to 45 % of the total mass of the composition.
The composition of the present disclosure further includes wood pulp in an amount ranging from 0.1 % to 10.0 % of the total mass of the composition.
The composition of the present disclosure further includes water.
In accordance with the composition of the present disclosure, the polyester fiber is at least one selected from the group consisting of polyethylene terephthalate (PET), polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polytrimethylene napthalate (PTN), polybutylene naphthalate (PBN), polyethylene naphthalate (PEN) and vectran.
In accordance with the composition of the present disclosure, the polyester fiber is recycled polyester.
In accordance with the composition of the present disclosure, the styrene-acrylate copolymer is at least one selected from the group consisting of styrene-butyl acrylate copolymer and styrene ethyl acrylate copolymer.
In accordance with the composition of the present disclosure, the water soluble epoxide is at least one selected from the group consisting of glycerol epoxide and sorbitol epoxide.
The present disclosure further provides an article prepared from the afore-stated modified cement composition, characterized by flexural strength above 97 kg/ cm2, wherein said article is selected from the group consisting of boards, slabs, and sheets.
The present disclosure even further provides a process for the preparation of an article composed of fibers and cement; said process comprising the following steps:
a. preparing a modified cement composition by admixing cement in an amount ranging from 50 % to 90 % of the total mass of the composition, asbestos fibers in an amount ranging from 1 % to 10 % of the total mass of the composition, modified polyester fibers in an amount ranging from 0.1 % to 1.0 % of the total mass of the composition, optionally, fly ash in an amount ranging from 25 % to 45 % of the total mass of the composition and optionally, wood pulp in an amount ranging from 0.1 % to 10.0 % of the total mass of the composition, in the presence of water, in any order;
b. molding said modified cement composition to obtain a molded article; and
c. air curing said molded article to obtain an article,
wherein said article is characterized by flexural strength of at least 97 kg /cm2 and is at least one selected from the group consisting of boards, slabs, and sheets.
In accordance with the process of the present disclosure, the step of air curing said molded article is carried out for a time period ranging from 20-28 days.
In accordance with the process of the present disclosure, the modified polyester fibers are polyester fibers modified with at least one surface modifying agent selected from the group consisting of styrene-acrylate co-polymers, styrene-butadiene polymers, acrylate homo-polymers, vinyl acetate polymers, vinyl acetate co-polymers, styrene-butadiene co-polymers, vinyl acetate emulsions, acrylic emulsions, non-ionic surfactant fatty alcohol ethoxylates, water soluble epoxides and organomodifed silicones and silanes.
In accordance with the process of the present disclosure, the polyester fiber is at least one selected from the group consisting of polyethylene terephthalate (PET), polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polytrimethylene napthalate (PTN), polybutylene naphthalate (PBN), polyethylene naphthalate (PEN) and vectran.
In accordance with the process of the present disclosure, the styrene-acrylate copolymer is at least one selected from the group consisting of styrene-butyl acrylate copolymer and styrene ethyl acrylate copolymer.
In accordance with the process of the present disclosure, the water soluble epoxide is at least one selected from the group consisting of glycerol epoxide and sorbitol epoxide.

DETAILED DESCRIPTION
In accordance with one aspect of the present disclosure, there is provided a modified cement composition consisting of cement, asbestos fibers, modified polyester fibers and optionally fly ash and wood pulp in pre-determined quantities. Typically, the composition contains cement in an amount ranging from 50 % to 90 % of the total mass of the composition and asbestos fibers in an amount ranging from 1 % to 10 % of the total mass of the composition.
The composition of the present disclosure includes use of modified polyester fibers, as a replacement of asbestos, in order to reduce the quantity of the latter in the composition. The modified polyester fibers are polyester fibers modified with at least one surface modifying agent which confers upon the polyester fiber, properties analogous to those of asbestos in the present context, thereby rendering the use of asbestos redundant. Moreover, the modification on the polyester fibers facilitates improved interfacial bonding between the polymers and cement thereby increasing the composite strength. Still further, the modified polyester fibers of the present disclosure are able to resist the alkalinity of cement; thereby functioning as a compatible constituent. The surface modifying agent of the present disclosure is at least one selected from the group consisting of styrene-acrylate co-polymers, styrene-butadiene polymers, acrylate homo-polymers, vinyl acetate polymers, vinyl acetate co-polymers, styrene-butadiene co-polymers, vinyl acetate emulsions, acrylic emulsions, non-ionic surfactant fatty alcohol ethoxylates, water soluble epoxides and organomodifed silicones and silanes. Typically, the styrene-acrylate copolymer is at least one selected from the group consisting of styrene-butyl acrylate copolymer and styrene ethyl acrylate copolymer. Furthermore, the water soluble epoxide is at least one selected from the group consisting of glycerol epoxide and sorbitol epoxide. The polyester fiber that is modified with the afore-stated surface modifiers is at least one selected from the group consisting of polyethylene terephthalate (PET), polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polytrimethylene napthalate (PTN), polybutylene naphthalate (PBN), polyethylene naphthalate (PEN) and vectran. In one embodiment, the polyester fiber is recycled polyester. Typically, the present composition includes modified polyester fibers in an amount ranging from 0.1 % to 1.0 % of the total mass of the composition.
The present composition further includes use of fly ash and wood pulp as fillers. The composition of the present disclosure includes fly ash in an amount ranging from 25 % to 45 % of the total mass of the composition and wood pulp in an amount ranging from 0.1 % to 10.0 % of the total mass of the composition. The composition of the present disclosure further includes water.
The composition of the present disclosure is used to prepare articles such as boards, columns and sheets. Due to the characteristic proportion of constituents used in the present composition, the articles prepared from the modified cement composition have at least above 97 kg/ cm2 flexural strength.
In accordance with another aspect of the present disclosure, there is provided a process for the preparation of the afore-stated article that includes the steps presented herein below.
The process initially includes admixing cement in an amount ranging from 50 % to 90 % of the total mass of the composition, asbestos fibers in an amount ranging from 1 % to 10 % of the total mass of the composition, modified polyester fibers in an amount ranging from 0.1 % to 1.0 % of the total mass of the composition, optionally fly ash in an amount ranging from 25 % to 45 % of the total mass of the composition and optionally wood pulp in an amount ranging from 0.1 % to 10.0 % of the total mass of the composition, in the presence of water, in any order, to prepare a modified cement composition. The modified cement composition is then molded in different shapes and dimensions depending upon the end use, to obtain molded articles. The molded articles are then air cured for a time period ranging from 20 to 28 days to obtain the article of the present disclosure.
The present disclosure will now be discussed in the light of the following non-limiting embodiments:
Example 1: Process for the preparation of the article of the present disclosure
0.5 g of 1.5 d, 6 mm polyester fibers were treated with 0.5 g of non-ionic surfactant blend of castor oil ethoxylates and then coated with 0.15 g of vinyl-acetate co-polymer emulsion by spraying technique. 1 g of the resultant surface modified polyester was mixed with 6.8 g of asbestos fibers, 83.2 g of cement, 52 g of fly ash, and 2 g of pulp in the presence of water to obtain a composition. The composition was then molded into slabs which were then air cured for 28 days to obtain slabs containing surface modified polyester. The flexural strength of the slabs was measured and is presented in Table 1.
Example 2: Process for the preparation of the article of the present disclosure
0.5 g of 1.5 d, 6 mm polyester fibers were treated with 0.5 g of non-ionic surfactant blend of castor oil ethoxylates and then coated with 0.15 g of styrene-acrylate co-polymer emulsion by spraying technique. 1 g of the resultant surface modified polyester was mixed with 6.8 g of asbestos fibers, 83.2 g of cement, 52 g of fly ash, and 2 g of pulp in the presence of water to obtain a composition. The composition was then molded into slabs which were then air cured for 28 days to obtain slabs containing surface modified polyester. The flexural strength of the slabs was measured and is presented in Table 1.
Example 3: Preparation of control
Slabs containing 6.8 g of asbestos fibers, 83.2 g of cement, 52 g of fly ash, 2 g of pulp and 1 g of non-modified polyester fibers were prepared in accordance with the process of Example 1 and 2. The flexural strength of these slabs was measured and was compared to that of the articles prepared in Example 1 and 2. The results obtained are presented in Table 1, herein below.
Table 1. Comparison of the flexural strength of the articles made from modified polyester and non-modified polyester
Sr. No. Sample Flexural Strength
Kg/ cm2
1 Slabs prepared in Example 3 (Control) 94.7
2 Slabs prepared in Example 1 (Present disclosure) 99
3 Slabs prepared in Example 2 (Present disclosure) 98

It is evident from the examples that use of modified polyester fibers in the cement composition of the present disclosure increases the flexural strength of the article prepared therefrom.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE
- The modified polyester fibers of the present disclosure are compatible with cement.
- The articles prepared from the composition of the present disclosure have a very high flexural strength (at least 97 kg /cm2)

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results.

The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention and the claims unless there is a statement in the specification to the contrary.

While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications in the process or compound or formulation or combination of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.