Claims:WE CLAIM:
1. A cement composition comprising:
i. cement in an amount in the range of 20 to 70% of the total mass of the cement composition;
ii. silica in an amount in the range of 20 to 60% of the total mass of the cement composition;
iii. flyash in an amount in the range of 10 to 30% of the total mass of the cement composition;
iv. pulp in an amount in the range of 4 to 9% of the total mass of the cement composition;
v. fiber in an amount in the range of 0.2 to 0.5% of the total mass of the cement composition; and
vi. a blend, in an amount in the range of 0.5 to 0.65% of the total mass of the cement composition, comprising an inorganic filler and at least one compound selected from the group consisting of an alkylene oxide, a surfactant and a grinding aid.
2. The cement composition as claimed in claim 1, wherein said fiber is of at least one material selected from the group of materials consisting of polyethylene terephthalate (polyester) and polypropylene.
3. The cement composition as claimed in claim 1, wherein said silica is at least one silicon based material selected from the group consisting of micro-silica, normal silica and siliceous material.
4. The cement composition as claimed in claim 1, wherein said pulp is lignocellulosic pulp selected from the group consisting of soft wood, cotton rag and paper.
5. The cement composition as claimed in claim 1, wherein said blend comprises an alkylene oxide and an inorganic filler; wherein the ratio of said alkylene oxide to said inorganic filler is in the range of 5:95 to 15:85 wt%.
6. The cement composition as claimed in claim 1, wherein said blend involves a grinding aid and a surfactant; wherein the ratio of said grinding aid to said surfactant is in the range of 10:90 to 30:70 wt%.
7. The cement composition as claimed in claim 1, wherein said blend comprises a grinding aid and an inorganic filler; wherein the ratio of said grinding aid to said inorganic filler is in the range of 10:90 to 30:70 wt%.
8. The cement composition as claimed in claim 1, wherein said alkylene oxide is at least one compound selected from the group consisting of ethylene oxide and propylene oxide.
9. The cement composition as claimed in claim 1, wherein said surfactant is at least one carboxylate salt selected from the group consisting of calcium stearate and sodium stearate.
10. The cement composition as claimed in claim 1, wherein said grinding aid is Diethanol-isopropanol amine (DEIPA).
11. The cement composition as claimed in claim 1, wherein said inorganic filler is at least one inorganic material selected from the group consisting of calcium carbonate (CaCO3), magnesium carbonate (MgCO3), talc and meta-kaoline.
12. A process for manufacturing a reinforced cement structure using the cement composition as claimed in claim 1, said process comprising the following steps:
i) mixing cement, silica and fiber to obtain a dry mixture;
ii) adding pulp to said dry mixture, followed by mixing to obtain a wet mixture;
iii) combining said wet mixture with water and a blend comprising an inorganic filler and at least one compound selected from the group consisting of an alkylene oxide, a surfactant and a grinding aid to obtain a slurry;
iv) pouring said slurry in a mould having predetermined dimensions and shape, followed by compressing said slurry in said mould, at a force in the range of 300 to 600 bar to obtain a cement structure; and
v) curing said cement structure at room temperature, over a time period in the range of 12 to 24 hours, followed by curing the resultant structure in an autoclave at a pressure in the range of 10 to 12 bar, at a temperature in the range of 170 to 180 °C, and over a time period in the range of 8 to 12 hours to obtain said reinforced cement structure,
wherein, said reinforced cement structure is characterized by having flexural strength in the range of 110 to 130 kg/m2 and water absorption capacity in the range of 20 to 25%.
13. The process as claimed in claim 12, wherein said reinforced cement structure is in form selected from the group consisting of a sheet, a beam and a slab.
, Description:FIELD
The present disclosure relates to cement composition and a process for preparing reinforced cement structure using the cement composition.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
Reinforced cement structure: The term “reinforced cement structure” is a cement structure in which the cement structure's relatively low tensile strength is improved by inclusion of a reinforcement having higher tensile strength. The reinforcement is usually reinforcing material and is usually embedded passively in the cement structure before the cement in the structure sets.
Denier: The term “denier” (abbreviated D) refers to, a unit of measure for the linear mass density of fibers. Denier is the mass in grams per 9000 meters of the fiber.
Flexural Strength: The term “Flexural Strength”, also known as modulus of rupture, or bend strength, or transverse rupture strength refers to a material property, defined as the stress in a material just before it yields in a flexure test. The transverse bending test is most frequently employed, in which a specimen having either a circular or rectangular cross-section is bent until fracture or yielding using a three point flexural test technique.
Pulp: The term “Pulp” refers to a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibers from wood, fiber crops, waste paper, or rags.

BACKGROUND
Cementitious compositions use cellulosic fibers for reinforcement of cement structures. Cellulosic fibers possess an inherent dispersing capacity to form webs in cement slurry and inherently bind with cement. The cement compositions comprising cellulosic fibers are autoclaved at high temperatures (around 180 °C) and high pressures (around 10 bar). These autoclaved cement structures have higher strength and dimensional stability in comparison to air-cured cement structures. However, use of cellulose fibers, which are made from wood pulp, results in draining of the natural resources.
Surface modified polyester fibers are utilized in the cement compositions as secondary reinforcement components. However, cement based compositions comprising polyester fibers, wood pulp and other additives are unable to show enhanced benefits after autoclaving due to the hydrophilicity of the wood pulp and effect of temperature and pressure on the reinforcement components.
Therefore, there exists a need for a cement composition comprising polyester fibers with enhanced cement binding properties, which possesses enhanced flexural strength.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
Another object of the present disclosure is to provide a cement composition.
Still another object of the present disclosure is to provide a process for preparing reinforced cement structure using the cement composition.
Yet another object of the present disclosure is to provide a reinforced cement structure having improved flexural strength and reduced hydrophilicity.
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
In a first aspect, the present disclosure relates to cement composition. The cement composition comprises cement in an amount in the range of 20 to 70% of the total mass of the cement composition, silica in an amount in the range of 20 to 60% of the total mass of the cement composition, flyash in an amount in the range of 10 to 30% of the total mass of the cement composition, pulp in an amount in the range of 4 to 9% of the total mass of the cement composition, fiber in an amount in the range of 0.2 to 0.5% of the total mass of the cement composition and a blend in an amount in the range of 0.5 to 0.65% of the total mass of the cement composition, comprising an inorganic filler comprising at least one selected from the group consisting of an alkylene oxide, a surfactant and a grinding aid.
In accordance with the present disclosure, the fiber is of at least one material selected from the group of materials consisting of polyethylene terephthalate (polyester) and polypropylene.
In accordance with the present disclosure, the silica is at least one silicon based material selected from the group consisting of micro-silica, normal silica and siliceous material.
In accordance with the present disclosure, the pulp is lignocellulosic pulp selected from the group consisting of soft wood, cotton rag and paper.
In accordance with one embodiment of the present disclosure, the blend comprises an alkylene oxide and an inorganic filler, wherein the ratio of the alkylene oxide to the inorganic filler is in the range of 5:95 to 15:85 wt%.
In accordance with another embodiment of the present disclosure, the blend includes a grinding aid and a surfactant, wherein the ratio of the grinding aid to the surfactant is in the range of 10:90 to 30:70 wt%.
In accordance with yet another embodiment of the present disclosure, the blend comprises a grinding aid and an inorganic filler, wherein the ratio of the grinding aid to the inorganic filler is in the range of 10:90 to 30:70 wt%.
In accordance with the present disclosure, the alkylene oxide is at least one compound selected from the group consisting of ethylene oxide and propylene oxide.
In accordance with the present disclosure, the surfactant is at least one carboxylate salt selected from the group consisting of calcium stearate and sodium stearate.
In accordance with the present disclosure, the grinding aid is Diethanol-isopropanol amine (DEIPA).
In accordance with the present disclosure, the inorganic filler is at least one inorganic material selected from the group consisting of calcium carbonate (CaCO3), magnesium carbonate (MgCO3), talc and meta-kaoline.
In a second aspect, the present disclosure provides a process for manufacturing a reinforced cement structure using the cement composition. The process comprises the step of mixing cement, silica and fiber to obtain a dry mixture. The dry mixture is added to the pulp, followed by mixing to obtain a wet mixture. The wet mixture is combined with water and the blend comprising an inorganic filler and at least one compound selected from the group consisting of an alkylene oxide, a surfactant and a grinding aid to obtain a slurry, which on pouring in a mold having predetermined dimensions and shape, is compressed in the mold, at a force in the range of 300 to 600 bar to obtain a cement structure. The cement structure is cured at room temperature, over a time period in the range of 12 to 24 hours, followed by curing the resultant structure in an autoclave at a pressure in the range of 10 to 12 bar, at a temperature in the range of 170 to 180 °C, and over a time period in the range of 8 to 12 hours to obtain the reinforced cement structure. The reinforced cement structure is characterized by having flexural strength in the range of 110 to 180 kg/cm2 and water absorption capacity in the range of 20 to 30%.
In accordance with the present disclosure, the reinforced cement structure is in form selected from the group consisting of a sheet, a board and a slab.
DETAILED DESCRIPTION
Conventionally, wood pulp is used in the preparation of cementitious compositions used for manufacturing reinforced cement structures. However, the amount of wood pulp in the cement composition has negative effect on water absorption/holding for outdoor application.
Similarly, surface modified polyester fibers are utilized in the cement and concrete material as a secondary reinforcement component. However, cement compositions comprising wood pulp, polyester fibers and other additives are unable to show enhanced benefits after autoclaving due to the hydrophilicity of the wood pulp and due to lack of improvement in the interaction of PET fibers with cement.
The present disclosure provides a cement composition comprising cement, micro-silica, a chemical formulation, polymeric fibers and wood pulp.
In a first aspect, the present disclosure relates to cement composition. The cement composition comprises cement in an amount in the range of 20 to 70% of the total mass of the cement composition, silica in an amount in the range of 20 to 60% of the total mass of the cement composition, flyash in an amount in the range of 10 to 30% of the total mass of the cement composition, pulp in an amount in the range of 4 to 9% of the total mass of the cement composition, fiber in an amount in the range of 0.2 to 0.5% of the total mass of the cement composition and a blend in an amount in the range of 0.50 to 0.65% of the total mass of the cement composition, comprising an inorganic filler and at least one compound selected from the group consisting of an alkylene oxide, a surfactant and a grinding aid.
In accordance with the embodiments of the present disclosure, the fiber is of at least one material selected from the group of materials consisting of polyethylene terephthalate (polyester) and polypropylene, having thickness in the range of 0.5 to 6 Denier (D), and length in the range of 1 to 12 mm.
In accordance with one embodiment of the present disclosure, the fiber is of polyethylene terephthalate material (polyester), having thickness of 1.5 Denier (D), and length in the range of 6 mm.
In accordance with the embodiments of the present disclosure, the cement composition further comprising fly ash in an amount in the range of 10 to 30% of the total mass of the cement composition.
In accordance with the embodiments of the present disclosure, the silica is at least one silicon based material selected from the group consisting of micro-silica, normal silica and siliceous material.
In accordance with one embodiment of the present disclosure, the silica is micro-silica.
In accordance with the embodiments of the present disclosure, the pulp is lignocellulosic pulp selected from the group consisting of soft wood, cotton rag and paper.
In accordance with one embodiment of the present disclosure, the pulp is soft wood pulp.
In accordance with the embodiments of the present disclosure, the blend comprises 30 to 60 wt% aqueous slurry.
The present disclosure provides a blend that modifies the surface of the polyester fibers and enhances the interaction of surface modified PET fibers with cement in a cement composition.
In accordance with one embodiment of the present disclosure, the blend comprises an alkylene oxide and an inorganic filler, wherein the ratio of the alkylene oxide to the inorganic filler is in the range of 5:95 to 15:85 wt%.
In accordance with another embodiment of the present disclosure, the blend is includes a grinding aid and a surfactant, wherein the ratio of the grinding aid to the surfactant is in the range of 10:90 to 30:70 wt%.
In accordance with yet another embodiment of the present disclosure, the blend comprises a grinding aid and an inorganic filler, wherein the ratio of the grinding aid to the inorganic filler is in the range of 10:90 to 30:70 wt%.
The use of PET fiber in the cement composition reduces the use of natural pulp thereby reducing the drain on natural resources.
The present disclosure provides a chemical formulation prepared from indigenous inorganic chemicals for preparing a hydrophilic polymer fibers, which are easily mixed with cement to obtain a cement formulation. The chemical formulation adheres to the surface of polymeric fibers or surface modified polyester fibers have excellent affinity towards cement and water.
The cement composition of the present disclosure provides reinforced cement structures having improved strength and reduced water absorption capacity.
The cement composition of the present disclosure reduces use of pulp in the cement composition by 15-20% in comparison to the conventional cement compositions.
The cement composition of the present disclosure provides reinforced cement structures with improved physical and mechanical properties.
The blend of the present disclosure is a combination of polymeric solution coated on to the polymeric fibers to increase wetting effect of the medium when mixed in cementitious matrix and to enhance the reactivity of the coated fibers in cementitious mixture.
The blend of the present disclosure when mixed with hydrophilic cut fiber of PET increases the interaction of the fiber with that of cementitious matrix by forming a network structure.
The blennd of the present disclosure, when coated on cut polyester fibers, shows wide range of application in asbestos’s replacement, non-asbestos cement sheet, self-curable concrete, paper making etc.
The study of this work is to make a process of easily applicable, low cost additive development and its application.
In accordance with the embodiments of the present disclosure, the alkylene oxide is at least one compound selected from the group consisting of ethylene oxide and propylene oxide.
In accordance with one embodiment of the present disclosure, the alkylene oxide is propylene oxide.
In accordance with another embodiment of the present disclosure, the alkylene oxide is ethylene oxide.
Surfactants are compounds which contain a hydrophilic end and hydrophobic end. Surfactants are added to cement compositions because the hydrophobic end reduces the surface tension resulting in the formation of stable bubbles. Whereas, the hydrophilic end interacts with the charges on the surface of cement and sand particles, thus facilitating the bubble to attach to the surface and assisting to produce a stable structure in the mix.
In accordance with the embodiments of the present disclosure, the surfactant is at least one carboxylate salt selected from the group consisting of calcium stearate and sodium stearate.
In accordance with one embodiment of the present disclosure, the surfactant is sodium stearate.
In accordance with another embodiment of the present disclosure, the surfactant is calcium stearate.
Calcium oxide in the cement reacts with acidic components in the cement, thereby forming tricalcium silicate, dicalcium silicate, tricalcium aluminate, and a ferrite solid solution phase approximating tetracalcium aluminoferrite, which lead to formation of clinkers. The clinkers are extremely hard and require a large amount of energy to suitably mill them into a powdered form. In order to reduce the energy for grinding the clinkers, grinding aids are introduced into the mill in small dosages and interground with the clinker to obtain a uniform powdery mixture. The grinding aids are also known to improve flowability of the powder, thereby reducing its tendency to form lumps during storage.
In accordance with the embodiments of the present disclosure, the grinding aid is diethanol-isopropanol amine (DEIPA).
In accordance with the embodiments of the present disclosure, the inorganic filler is at least one inorganic material selected from the group consisting of calcium carbonate (CaCO3), magnesium carbonate (MgCO3), talc and meta-kaoline.
In accordance with one embodiment of the present disclosure, the inorganic filler is calcium carbonate (CaCO3).
In a second aspect, the present disclosure provides a process for manufacturing a reinforced cement structure using the cement composition. The process comprises the step of mixing cement, silica and fiber to obtain a dry mixture. The dry mixture is added to the pulp, followed by mixing to obtain a wet mixture. The wet mixture is combined with water and the blend comprising an inorganic filler and at least one compound selected from the group consisting of an alkylene oxide, a surfactant and a grinding aid to obtain slurry, which on pouring in a mold having predetermined dimensions and shape, is compressed in the mold, at a force in the range of 300 to 600 bar to obtain a cement structure. The cement structure is cured at room temperature, over a time period in the range of 12 to 24 hours, followed by curing the resultant structure in an autoclave at a pressure in the range of 10 to 12 bar, at a temperature in the range of 170 to 180 °C, and over a time period in the range of 8 to 12 hours to obtain the reinforced cement structure. The reinforced cement structure is characterized by having flexural strength in the range of 110 to 180 kg/m2 and water absorption capacity in the range of 20 to 30%.
The surface modified polyester fibers of the present disclosure reduce water absorption in cement structures manufactured using the cement composition.
The cement composition of the present disclosure can be cured by different methods such as air curing or autoclave curing.
The cement composition of the present disclosure is preferably cured using an autoclave.
Autoclave curing of the cement composition is preferred because the cement structures obtained by autoclave curing are more durable and dimensionally stable.
Autoclave curing of the products manufactured from cement composition of the present disclosure increases the curing speed and the final strength of the product.
A reactive ingredient can enhance the strength parameter and reduce water retention in the article.
In accordance with the embodiments of the present disclosure, the reinforced cement structure is in form selected from the group consisting of a sheet, a board and a slab.
The present disclosure is further described in light of the following laboratory scale experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. These laboratory scale experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial/commercial scale.

Experimental details
Table 1: Cement compositions:
Components Control
(w/o fiber & CC chemical) polyester Fiber + CC-30 polyester Fiber + CC-31
Cement 37.70% 37.46% 37.35%
Fly ash 31.52% 31.32% 31.22%
Silica 22.80% 23.55% 23.48%
Pulp (Imported) 8.00% 6.76% 6.74%
polyester fiber 0 0.30% 0.30%
CC Chemical 0 0.61% 0.91%
Total solid 100.0% 100.0% 100.0%
MRA (Kg/cm2) 105 123 116
Water absorption % 29.89 22.07 23.06

Comparative Experiment 1: Preparation of reinforced cement structures using the conventional cement composition
Cement (62.2 g), flyash (52 g) micro-silica (37.6 g), followed by addition of refined ‘soft wood pulp’ (13.2 g) in water (250 g) to obtain a wet mixture. Water (200 g) was added to the wet mixture to obtain a slurry (615 g), which was poured into a mold having the following dimensions: 200 mm length x 78 mm width x 6 mm thickness and pressed in a hydraulic press, at a force of 500-600 bar to form a panel. The panel was then humid cured for one day followed by autoclave curing at about 175 ± 5 °C for 10 hrs.
The reinforced panel manufactured in comparative experiment 1, was evaluated for its flexural strength and water absorption capacity and the results are summarized in Table 2.
Experiment 2: Preparation of reinforced cement structures using the cement composition of the present disclosure
Cement (62.2 g ), micro-silica (39.1 g) and flyash (52 g) were mixed, followed by addition of refined ‘soft wood pulp’ (11.22 g) in water (250 g) to obtain a wet mixture. Ethylene Oxide (EO)/Propylene Oxide (PO) condensate (25 g) was added to C-22 wax (75 g) to obtain a mixture (100 g). This mixture (0.5 g) was coated over polyethylene terephthalate fibers (0.5 g polyester fibers of 1.5 d, 6 mm) and then mixed with the wet mixture, followed by addition of Water (200 g) to the wet mixture to obtain a slurry (615 g), which was poured into a mold having the following dimensions: 200 mm length x 78 mm width x 6 mm thickness and pressed in a hydraulic press, at a force of 500-600 bar to form a panel. The panel was then humid cured for one day followed by autoclave curing at about 175 ± 5 °C for 10 hrs.
The reinforced panel manufactured in experiment 2, was evaluated for its flexural strength and water absorption capacity and the results are summarized in Table 2.
Experiment 3: Preparation of reinforced cement structures using the cement composition of the present disclosure
Cement (62.2 g), micro-silica (37.6 g), flyash (52 g) and polyethylene terephthalate fibers (0.5 g polyester fibers of 1.5 d, 6 mm) were mixed, followed by addition of refined ‘soft wood pulp’ (11.2 g) in water (250 g) to obtain a wet mixture. Ethylene Oxide (EO)/Propylene Oxide condensate (PO) (10 g) and talc (90 g), were mixed with water (100 g), to obtain an emulsion (200 g). This emulsion (1 g) was added to the wet mixture, followed by addition of Water (200 g) to obtain a slurry (615 g), which was poured into a mold having the following dimensions: 200 mm length x 78 mm width x 6 mm thickness and pressed in a hydraulic press, at a force of 500-600 bar to form a panel. The panel was then humid cured for one day followed by autoclave curing at about 175 ± 5 °C for 10 hrs.
The reinforced panel manufactured in experiment 3, was evaluated for its flexural strength and water absorption capacity and the results are summarized in Table 2.
Experiment 4: Preparation of reinforced cement structures using the cement composition of the present disclosure
Cement (62.2 g), micro-silica (39.1 g), flyash (52 g) and polyethylene terephthalate fibers (0.5 g polyester fibers of 1.5 d, 6 mm) were mixed, followed by addition of refined ‘soft wood pulp’ (11.2 g) in water (250 g) to obtain a wet mixture. Ethylene Oxide (EO)/Propylene Oxide condensate (PO) (10 g) and Calcium stearate (90 g), were mixed with water (200 g), to obtain an emulsion (300 g). This emulsion (1.5 g) was added to the wet mixture, followed by addition of Water (200 g) to obtain a slurry (615 g), which was poured into a mold having the following dimensions: 200 mm length x 78 mm width x 6 mm thickness and pressed in a hydraulic press, at a force of 500-600 barto form a panel. The panel was then humid cured for one day followed by autoclave curing at about 175 ± 5 °C for 10 hrs.
The reinforced panel manufactured in experiment 4, was evaluated for its flexural strength and water absorption capacity and the results are summarized in Table 2.
Experiment 5: Preparation of reinforced cement structures using the cement composition of the present disclosure
Cement (62.2 g), micro-silica (39.1 g), flyash (52 g) and polyethylene terephthalate fibers (0.5 g polyester fibers of 1.5 d, 6 mm) were mixed, followed by addition of refined ‘soft wood pulp’ (11.2 g) in water (250 g) to obtain a wet mixture. Ethylene Oxide (EO)/Propylene Oxide condensate (PO) (10 g) and Calcium carbonate (CaCO3, limestone) (90 g), were mixed with water (11 g), to obtain a mixture (111 g). This mixture (0.55 g) was added to the wet mixture, followed by addition of Water (200 g) to obtain a slurry (615 g), which was poured into a mold having the following dimensions: 200 mm length x 78 mm width x 6 mm thickness and pressed in a hydraulic press, at a force of 500-600 bar to form a panel. The panel was then humid cured for one day followed by autoclave curing at about 175 ± 5 °C for 10 hrs.
The reinforced panel manufactured in experiment 5, was evaluated for its flexural strength and water absorption capacity and the results are summarized in Table 2.
Experiment 6: Preparation of reinforced cement structures using the cement composition of the present disclosure
Cement (62.2 g), micro-silica (39.1 g), fly ash (52 g) and polyethylene terephthalate fibers (0.5 g polyester fibers of 1.5 d, 6 mm) were mixed, followed by addition of refined ‘soft wood pulp’ (11.2 g) in water (250 g) to obtain a wet mixture. Ethylene Oxide (EO)/Propylene Oxide condensate (PO) (10 g) and Calcium phosphate (CaPO4) (90 g), were mixed with water (42 g), to obtain a mixture (142 g). This mixture (0.7 g) was added to the wet mixture to obtain a slurry (615 g), which was poured into a mold having the following dimensions: 200 mm length x 78 mm width x 6 mm thickness and pressed in a hydraulic press, at a force of 500-600 bar to form a panel. The panel was then humid cured for one day followed by autoclave curing at about 175 ± 5 °C for 10 hrs.
The reinforced panel manufactured in experiment 6, was evaluated for its flexural strength and water absorption capacity and the results are summarized in Table 2.
Experiment 7: Preparation of reinforced cement structures using the cement composition of the present disclosure
Cement (62.2 g), micro-silica (39.1 g), flyash (52 g) and polyethylene terephthalate fibers (0.5 g polyester fibers of 1.5 d, 6 mm) were mixed, followed by addition of refined ‘soft wood pulp’ (11.2 g) in water (250 g) to obtain a wet mixture. Diethanol-isopropyl amine (DEIPA) (10 g) and Sodium Stearate (40 g), were mixed with water (50 g), to obtain a mixture (100 g). This mixture (1 g) was added was added to the wet mixture, followed by addition of Water (200 g) to the wet mixture to obtain a slurry (615 g), which was poured into a mold having the following dimensions: 200 mm length x 78 mm width x 6 mm thickness and pressed in a hydraulic press, at a force of 500-600 bar to form a panel. The panel was then humid cured for one day followed by autoclave curing at about 175 ± 5 °C for 10 hrs.
The reinforced panel manufactured in experiment 7, was evaluated for its flexural strength and water absorption capacity and the results are summarized in Table 2.
Experiment 8: Preparation of reinforced cement structures using the cement composition of the present disclosure
Cement (62.2 g), micro-silica (39.1 g), flyash (52 g) and polyethylene terephthalate fibers (0.5 g polyester fibers of 1.5 d, 6 mm) were mixed, followed by addition of refined ‘soft wood pulp’ (11.2 g) in water (250 g) to obtain a wet mixture. Diethanol-isopropyl amine (DEIPA) (10 g) and Calcium carbonate (40 g), in water (50 g), to obtain a mixture (100 g). This mixture (1 g) was added to the wet mixture, followed by addition of Water (200 g) to the wet mixture to obtain a slurry (615 g), which was poured into a mold having the following dimensions: 200 mm length x 78 mm width x 6 mm thickness and pressed in a hydraulic press, at a force of 500-600 bar 10 - 14 tonnes to form a panel. The panel was then humid cured for one day followed by autoclave curing at about 175 ± 5 °C for 10 hrs.
The reinforced panel manufactured in experiment 8, was evaluated for its flexural strength and water absorption capacity and the results are summarized in Table 2.
Experiment 9: Preparation of reinforced cement structures using the cement composition of the present disclosure
Cement (62.2 g), micro-silica (39.1 g), fly ash (52 g) and polyethylene terephthalate fibers (0.5 g polyester fibers of 1.5 d, 6 mm) were mixed, followed by addition of refined ‘soft wood pulp’ (11.2 g) in water (250 g) to obtain a wet mixture. Diethanol-isopropyl amine (DEIPA) (10 g) and Calcium Stearate (40 g), were mixed with water (101 g), to obtain a mixture (151 g). This mixture (1.5 g) was added was added to the wet mixture, followed by addition of Water (200 g) to the wet mixture to obtain a slurry (615 g), which was poured into a mold having the following dimensions: 200 mm length x 78 mm width x 6 mm thickness and pressed in a hydraulic press, at a force of 500-600 bar to form a panel. The panel was then humid cured for one day followed by autoclave curing at about 175 ± 5 °C for 10 hrs.
The reinforced panel manufactured in experiment 9, was evaluated for its flexural strength and water absorption capacity and the results are summarized in Table 2.

Table 2: Flexural strength and Water absorption capacity of panels prepared using the cement compositions of the present disclosure
Sr. No. Particulars Details of formulation Flexural strength MRA (kg/cm2) Water absorption
1 Sheets manufactured in comparative example 1 NA 106 32%
2 AC-10 coated over polyester (1.5 deiner short cut fiber), 6mm EO/PO (Ethylene Oxide/ Propylene Oxide condensate)
: C-22 wax (emulsion of Paraffin wax), 25:75 83 30%
3 AC-11A + polyester 1.5d, 6mm EO/PO : Talc, 10:90, 50% slurry in water 67 32%
4 AC-12A + polyester 1.5d, 6mm EO/PO : Calcium stearate, 10:90, 33% slurry in water 112 20%
5 AC-23A + polyester 1.5d, 6mm EO/PO : CaCO3 (Lime Stone), 10:90, 90% slurry in water 94 30%
6 AC-28 + polyester 1.5d, 6mm EO/PO : Calcium Phosphate, 10:90, 70% slurry in water 96 40%
7 AC-29 + polyester 1.5d, 6mm DEIPA (Diethanol-isopropyl amine) : Sodium Stearate, 20:80, 50% slurry in water 112 27%
8 AC-30 + polyester 1.5d, 6mm DEIPA : CaCO3, 20:80, 50% slurry in water 123 22%
9 AC-31 + polyester 1.5d, 6mm DEIPA : Calcium Stearate, 20:80, 33% slurry in water 117 23%

It is clearly observed from Table-2, that the reinforced cement panel/structures manufactured in Examples 4, and 7-9, using the cement composition of the present disclosure, have enhanced flexural strength in the range of 110 to 130 kg/m2 in comparison with the reinforced cement panel/structures manufactured using the conventional cement composition, which has enhanced flexural strength of 106 kg/m2. Similarly, the reinforced cement panel/structures manufactured in Examples 4, and 7-9, using the cement composition of the present disclosure, have water absorption capacity in the range of 20 to 25% in comparison with the reinforced cement panel/structures manufactured using the conventional cement composition, which has water absorption capacity of 32%.
It is clearly observed from the components of the cement compositions presented in Table-1, that in the present disclosure which uses polyester fibers reduces the use of pulp by an amount in the range of 15 to 20%.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of:
- cement composition comprising surface modified polyester fibers having improved wettability;
- cement composition comprising reduced amount of cellulose pulp;
- cement composition having reduced water absorption capacity; and
- a process for manufacturing reinforced cement structures having enhanced strength.
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. 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 to the formulation 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 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 unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.