Description:FIELD OF INVENTION:
The present invention relates to building material compositions, comprising cement, particularly of compositions involving cement and blended fibres. It relates to the use of fibres for improvising properties of concrete compositions and a method of preparation thereof.
BACKGROUND OF THE INVENTION:
KR102253856B1 discloses concrete structure reinforcing panel and method for reinforcing concrete structure thereof, comprising a mainframe unit (100); and a fiber (200) installed in a forward and backward directions in the mainframe unit (100). The fiber (200) includes an aramid fiber (210), basalt fiber (220), and glass fiber (230), which are installed at the area ratio of 1 to 1 to 5 through 1 to 3 to 8 based on the cross-sectional area. Here, placed are aramid fiber with 2% or higher of rupture strain, glass fiber with a lower strain than that of the aramid fiber, and basalt fiber with an excellent heat resistance.
CN112279568A discloses a concrete preparation process, wherein the raw materials are as follows, 400 parts of andesite 300-containing material, 400 parts of basalt 300-containing material, 400 parts of heavy slag 300-containing material, 200 parts of crushed clay brick 100-containing material, 200 parts of crushed iron ore 100-containing material, 30-40 parts of chrome magnesia brick, 20-30 parts of expanded polystyrene, 20-30 parts of expanded perlite, 20-30 parts of phenylenebrode fine aggregate, 30-40 parts of zinc oxide powder, 10-20 parts of polyphenolic aldehyde, 10-20 parts of polysulfone resin, 40-50 parts of glass fiber, 20-30 parts of steel fiber, 10-20 parts of polypropylene fiber, 30-40 parts of foaming agent, 30-40 parts of water reducer, 40-50 parts of colorant and cement slurry.
CN110577389A discloses a high-strength fiber concrete and preparation method thereof wherein the high-strength fiber concrete comprises the following raw material components: 50-60 parts of broken stone, 400 parts of cement 350-containing materials, 2-2.5 parts of water reducing agent, 200 parts of water 150-containing materials, 30-45 parts of fiber mixture, 60-80 parts of adhesive, 15-20 parts of bentonite, and 40-50 parts of calcium chloride aqueous solution and sodium carbonate aqueous solution with the same concentration respectively.
The processes and formulations described in the prior arts and existing at markets, involving reinforcement of cement with fibres are complicated, require raw materials that may be expensive, are difficult to handle. Further, such concrete compositions may have difficulties during application time. It is understood that there is a requirement of continuously evaluating and formulating compositions which are used as high strength construction material.
It is also understood from the existing state of art that reinforcing concrete with a fibre mixture also needs evaluation and to evolve a new advantageous fibre reinforced concrete composition which is advantageous over other compositions and is not difficult to handle.
The present invention seeks to overcome the above-mentioned problems existing in the prior art by providing for a fibre mixture and a concrete composition.
SUMMARY:
According to an embodiment, there is disclosed a concrete composition, comprising: a cement binder, a fibre mixture, plasticiser, and an aggregate mixture, wherein for every CUM, the ratio of the ingredients is for every 1 parts of cement binder, 3.6 parts of aggregate mixture, 0.007 parts of plasticiser and 0.002 parts of the fibre mixture.
According to another embodiment, there is disclosed a fibre mixture for a concrete composition, comprising a combination of glass fibres, basalt fibres and brass coated steel fibre.
According to yet another embodiment, there is a disclosed concrete composition for construction, comprising a cement binder, a fibre mixture, plasticiser, an aggregate mixture and water, wherein for every CUM, the ratio of the ingredients is for every 1 parts of cement binder, 3.6 parts of aggregate mixture, 0.007 parts of plasticiser, 0.002 parts of the fibre mixture and 0.3 parts of water.
OBJECT OF THE INVENTION:
It is an object of the present invention to provide for a concrete with improved compressive strength.
It is another object to provide for a concrete composition with a unique fibre mixture as its reinforcement.
It is yet another object to provide for a concrete composition with improved mechanical properties.
It is yet another object to provide for a fibre reinforced concrete composition.
It is yet another object to provide for a fibre mixture, which is a combination of a plurality of fibres.
DESCRIPTION:
The following description illustrates various embodiments of the present invention and ways of implementation. The embodiments described herein are not intended to be limited to the disclosure and that the same is in no way a limitation. The invention may be embodied in different forms without departing from the scope and spirit of the disclosure.
Ranges may be expressed herein as form "about" one particular value, and/or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/ or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment It will be further understood that the endpoints of each of the ranges are significant both in relation to the other end point, and independently of the other endpoint.
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.
The present invention discloses a concrete composition with improved mechanical properties in comparison with a control composition.
The present invention comprises a mixture of blended fibres to increase compressive strength of concrete mix by 4.7%. In the present invention, concrete, and mixture of Fibres of different material/aspect ratios are blended in way that contribute to increase in compressive strength of concrete thereby reducing cement content making concrete more sustainable and economical.
In an aspect of the present invention, there is disclosed a fibre mixture composition which is made of specifically chosen fibres at a particular ratio to act as a reinforcement to a cement binder that can improve adhesion and increase performance of the reinforced concrete.
In another aspect of the present invention, there is disclosed a concrete composition comprising cement as a binder, a fibre mixture, an aggregate mixture, and plasticiser in a specific proportion. Preferably, the composition is in dry state.
In yet another aspect of the present invention, there is disclosed building material composition, wherein the dry concrete composition is mixed with a specific proportion of water to obtain the building/construction material composition, i.e., a concrete slurry.
It is a specific advantage of the present invention that the use of fibres, especially steel fibres, in combination with other fibres, synergistically increases the mechanical properties of the concrete composition, especially the compressive strength.
The cement composition according to the present invention has much higher mechanical properties as compared to conventional cement composition comprising stones, mortars, fillers, etc.
In an aspect of the present invention, a specific fibre mixture is disclosed, which provides reinforcement to the cement binder. The fibre mixture is a combination of particular fibres at a specific proportion.
Fibres may be chosen from steel fibres, natural fibres, synthetic fibres, or mixtures thereof.
Due to prevalence of scarcity of natural fibres, there is a continuous search for alternative fibres which can suit industry requirements. Mere use of concrete without reinforcement leads to lower mechanical properties and issues of performance such as cracks, less durability etc.
Synthetic fibres may be chosen from a nickel fibre, glass fibre, carbon fibre, graphite fibre, mineral fibre, oxidized carbon fibre, oxidized graphite fibre, oxidized polyacrylonitrile fibre, steel fibre, metallic fibre, metal-coated carbon fibre, metal-coated glass fibre, metal-coated graphite fibre, metal-coated ceramic fibre, nickel-coated graphite .fibre, nickel-coated carbon fibre, nickel-coated glass fibre, quartz fibre, ceramic fibre, silicon carbide fibre, stainless steel fibre, titanium fibre, nickel alloy fibre, brass-coated steel fibre, polymeric fibre, polymer-coated carbon fibres, polymer-coated graphite fibre, polymer-coated glass fibre, ceramic-coated carbon fibre, ceramic-coated graphite fibre, ceramic coated glass fibre, aramid fibre, basalt fibre, alkaline resistant glass fibre, an E glass fibre, S-glass fibre, basalt fibre, polyethylene fibre, Sic fibre, or BN fibre, or combinations thereof.
Preferably fibres such as glass fibres, basalt fibres and steel fibres are used.
In a preferred embodiment, steel fibres such as brass coated steel fibres are used in the fibre mixture.
Generally steel fibres have a length in the range of 5 mm - 60 mm and a diameter in the range of 0.1 mm - 1 mm. However, it is not a limitation to opt for other variations. Further, the steel fibres may also be chemically and/or mechanically modified, by suitable processes for making it adequate for the reinforcement mixture. Also, steel fibres of any length may be chosen, which may also have curved or hooked ends.
Typically, the chosen range of steel coated fibre is, with a length in the range of 5 - 30 mm.
In a preferred embodiment, the length of the brass coated steel fibre used is 3mm with a diameter of 0.2mm.
Basalt fibre is made by pultrusion of volcanic rocks and melted in blast furnaces. The fibre is drawn, as opposed to extrusion. This process makes it possible to create a continuous fibre. Basalt fibres are supposed to have better properties than other fibres. Basalt fibres of diameter range 12mm were used in the fibre mixture.
Glass fibres are formed from melts and manufactured in various compositions by changing the amount of raw materials like sand for silica, clay for alumina, calcite for calcium oxide, and colemanite for boron oxide.
Alkali Resistant (AR) Glass Fibers are designed specifically for use in concrete. They are manufactured from a specially formulated glass composition with an optimum level of Zirconia (ZrO2) to be suitable for use in concrete. AR Glass Fibers are particularly suitable for Premix GFRC and other mortar and concrete reinforcement applications. They have high tensile strength and modulus, do not rust like steel, and are easily incorporated into concrete mixes.
In a preferred embodiment, AR Glass fibres of diameter 12mm, 24mm and 48mm were used for the purpose.
In an alternate embodiment, AR glass fibres of any diameter within the range of 12-48 mm may be used for the purpose. The composition of blended fibre mixture comprises of the following:
AR Glass fibre 12mm - 14.35%
AR Glass fibre 24 mm - 19.85%
AR Glass fibre 48 mm - 22.40%
Basalt Fiber 12 mm - 18.40%
Brass Coated steel fibre 13 mm - 25%
The blend of fibres or fibre mixture is obtained by reducing size of the above-mentioned fibres by regular known processing such as cutting, milling, grinding etc. until a fine mixture of fibres is obtained.
In a preferred embodiment, the fibre mixture is in dry state.
In another aspect of the present invention, there is disclosed a concrete composition comprising of a binder, fibre mixture, aggregate mixture, plasticiser, and optionally other known ingredients.
It uses commonly available cement as a binder for the formulation.
In a preferred embodiment, Ordinary Portland Cement (OPC) is used as the cement binder. In alternate embodiments, it is possible to use blended cements as cement binder such as Portland composite cement (CEM II), blast furnace cement (CEM III), pozzolanic cement (CEM IV) and composite cement (CEM V) according to DIN 197-1 in addition to OPC.
In alternate embodiment, cements such as calcium sulfoaluminate cement, calcium aluminate cement, or mixtures thereof or any other available special cement may be used in addition to the OPC or as a mixture thereof.
Concrete plasticizers are also called water reducers, hence also known as water-reducing admixtures. Plasticizers are the admixtures used to mix in cement to improve their qualities and make them suitable for construction. Preferably, a plasticiser which works on principles of dispersion is used for the concrete composition. A plasticiser which is based on polycarboxylic ether polymer with long lateral chains is used.
The fibre mixture is as discussed in the first aspect of the present invention.
Further, the composition of the present invention advantageously further comprises a mixture of aggregates or fillers. Aggregates can be any material that is non-reactive and aids in improvement of properties of a concrete composition. Aggregates may be selected from for example rock, crushed stone, gravel, slag, sand, especially quartz sand, river sand and/or manufactured sand, recycled concrete, glass, expanded glass, pumice, perlite, vermiculite, and/or fine aggregates such as ground limestone, and/or ground dolomite.
Optionally and based on requirement, the composition may also have and include ingredients such as accelerators, retarders, air entrainers, stabilizers, viscosity modifiers, thickeners, water reducers, accelerators, retarders, water resisting agents, strength enhancing additives, blowing agents, pigments, corrosion inhibitors, etc.
In another aspect of the present invention, there is disclosed a concrete composition, which is a wet composition or as a building material. In this embodiment, the dry concrete composition is mixed with a specific proportion of water.

Table 1 discloses a concrete composition, with and without the fibre mixture according to the present invention.

TABLE 1
Ingredient Description Control Mix
(without fibre mixture) Cement mix with fibre mixture
Cement, kg/CUM Ultratech OPC 53 G 498 498
20mm, kg/CUM - 561 561
10mm, kg/CUM - 512 512
Crush Sand, kg/CUM - 711 711
Water, lit/CUM - 154 154
Plasticizer, kg/CUM Fosroc Auramix 300 3.5 3.5
Fibre mixture, kg/CUM Mix of fibres according to present invention - 0.9
The mechanical properties of both the compositions were evaluated and are identified in tables 2-6.
Table 2 identifies slump retention properties of the concrete composition.

TABLE 2
Test Test method Control Mix
(without fibre mixture) Cement mix with fibre mixture
Workability: Slump Retention (mm) IS 1199 -1959
Initial 220 210
After 60 minutes 200 200
After 120 minutes 200 190
Table 3 identifies flexural strength of the concrete composition.
TABLE 3
Test Test method Control Mix
(without fibre mixture) Cement mix with fibre mixture
Flexural strength (kg/cm2) IS 516: 1959 RA 2013
After 28 days 36.0 43.3
(increased by 17%)
Table 4 identifies the change of length in hardened concrete of the concrete composition.
TABLE 4
Test Test method Control Mix
(without fibre mixture) Cement mix with fibre mixture
Length Change of Hardened Concrete (%) IS 516 Part-6 : 2020
After 28 days -0.021 -0.015
(reduced by 30%)
Table 5 identifies split tensile strength of the concrete composition.
TABLE 5
Test Test method Control Mix
(without fibre mixture) Cement mix with fibre mixture
Split Tensile Strength, (MPa) ASTM C 496 / C 496 M : 2017
After 28 days 2.4 2.9
(increased by 18%)
Table 6 identifies the compressive strength of the concrete composition.
TABLE 6

The mixture of blended fibres to increase compressive strength of concrete mix by at-least 4% and increase crack resistance by 40%.
By reducing cement content, the present invention aims at making concrete more sustainable and economical at the same time decrease in shrinkage cracks attribute to durability.
The above-mentioned description illustrates and depicts various embodiments of the present invention. However, it will be appreciated that numerous changes and modifications are likely to occur as per user requirements, and it is intended in the appended claims to cover all these changes and modifications which fall within the true spirit and scope of the present invention.
, Claims:WE CLAIM:
1. A concrete composition, comprising: a cement binder, a fibre mixture, plasticiser, and an aggregate mixture, wherein for every CUM, the ratio of the ingredients is for every 1 parts of cement binder, 3.6 parts of aggregate mixture, 0.007 parts of plasticiser and 0.002 parts of the fibre mixture.
2. The composition as claimed in claim 1, wherein the fibre mixture is a combination of glass fibres, basalt fibres and brass coated steel fibre.
3. The composition as claimed in claim 1, wherein the aggregate mixture is composed of coarse aggregates, fine aggregates and coarse sand.
4. The composition as claimed in claims 1 and 3, wherein the particle size of coarse aggregates is 20 mm.
5. The composition as claimed in claims 1 and 3, wherein the particle size of fine aggregates is 10 mm.
6. The composition as claimed in claim 1, wherein ratio of coarse aggregates, fine aggregates and coarse sand is 1:0.9:1.3.
7. The composition as claimed in claim 1, wherein the composition is a dry one.
8. The composition as claimed in claim 1, wherein the composition is added with 0.3 parts of water for every 1 parts of cement binder to make the composition a wet slurry.
9. The composition as claimed in claim 1, wherein the proportion of glass fibres, basalt fibres and brass coated steel fibre is 3:1:1.4.
10. The composition as claimed in claim 1, wherein the diameter of glass fibres ranges between 12-48 mm.
11. A fibre mixture for a concrete composition, comprising a combination of glass fibres, basalt fibres and brass coated steel fibre.
12. The mixture as claimed in claim 11, wherein the glass fibres used have a diameter in the range of 12-48 mm.
13. The mixture as claimed in claims 11 and 12, wherein the preferred diameters of glass fibres are 12 mm, 24 mm and 48mm.
14. The mixture as claimed in claim 11, wherein the glass fibres are alkali resistant.
15. The mixture as claimed in claim 11, wherein the proportion of glass fibres, basalt fibres and brass coated steel fibre is 3:1:1.4.
16. The mixture as claimed in claims 11 and 15, wherein the proportion of glass fibres of diameter 12 mm is 14.35%, of diameter 24 mm is 19.85% and of diameter 48 mm is 22.40%.
17. A concrete composition for construction, comprising a cement binder, a fibre mixture, plasticiser, an aggregate mixture and water, wherein for every CUM, the ratio of the ingredients is for every 1 parts of cement binder, 3.6 parts of aggregate mixture, 0.007 parts of plasticiser, 0.002 parts of the fibre mixture and 0.3 parts of water.
18. The composition as claimed in claim 17, wherein the fibre mixture is a combination of glass fibres, basalt fibres and brass coated steel fibre.
19. The composition as claimed in claim 17, wherein the proportion of glass fibres, basalt fibres and brass coated steel fibre is 3:1:1.4.
20. The composition as claimed in claim 17, wherein the aggregate mixture is composed of coarse aggregates, fine aggregates and coarse sand.