A high strength rapid setting concrete composition and method for preparation thereof

Abstract

The present invention relates to a high strength rapid setting concrete composition and a method of preparing thereof. This high strength rapid setting concrete composition comprising a cementitious material, a metal oxide / aluminate, a water reducer, an aggregate, a retarder, an accelerator, a fiber, and an alkali metal salt. The method of preparing the concrete composition comprises the preparation of a slurry material comprising cementitious material, metal oxide / aluminate, accelerator, aggregate, and water reducer; and preparation of a powdered mixture comprising alkali metal salt, water reducer, retarder, accelerator and fiber. The concrete composition is prepared by mixing 85-95% of the slurry 5-15% of the powder mixture at repairing site. This concrete composition is hardened within 35 minutes after the powder mixture is added to the slurry at the repairing site.

Description

[0001] A HIGH STRENGTH RAPID SETTING CONCRETE COMPOSITION AND METHOD FOR PREPARATION THEREOF

[0002] FIELD OF INVENTION

[0003]

[0001] The present invention relates to a concrete composition and a method for preparation thereof. Particularly, the present invention relates to a high strength rapid setting concrete composition having prolonged working time and ability to be transported in large volumes over long distances and its method of preparation.

[0004] BACKGROUND OF THE INVENTION

[0005]

[0002] Quick-setting concrete is a special type of concrete mixture special that requires less setting time, and hardening of the cement to be less. The quick-setting concrete composition predominantly used for rapid repairs of concrete structures or roads, are generally supplied in pre-packed bags. These pre -bagged concrete compositions are activated by adding water before pouring the composition onto the construction site or repair area. This concrete composition normally sets within 15 minutes and attain a strength of more than 15 Mpa in 2 hours. In this methodology, only a small volume of concrete is mixed at a time because of its rapid setting nature. Therefore, mixing this rapid setting concrete composition in traditional ready mix concrete trucks or a similar set up is virtually impossible because of the fast-setting nature of these concrete compositions.

[0006]

[0003] Either traditional concretes have an extended working time with a longer return to service time or the traditional rapid setting concrete will have a shorter working time and may not be used in large volumes. Because of ever-increasing urbanization, the need to produce large volumes of rapid setting concrete is becoming more day-by-day. These rapid setting concrete compositions become more relevant for the repair or relaying of roads in cities, ports, and airports, etc. where the existing movement of traffic cannot be stopped for a longer period. The existing rapid setting one -part concrete compositions with shorter working time may not be transported over longer distances because of its quick setting nature.

[0007]

[0004] US6641658B1 discloses a rapid setting cementitious composition, which is activated with water before casting in a mold. These cementitious compositions having shorter working time and may not be transported over long distances.

[0008]

[0005] WO2017089899A1 discloses a rapid setting hydraulic cement composition, which is activated with water just before pouring it onto the repair site. The cement composition comprises of Class C fly ash, which is a waste coming from burning of anthracite coal and the availability of such fly ashes causes an environmental concern.

[0009]

[0006] US9394200B2 discloses the pozzolanic cement compositions, which is activated with water before pouring it onto the construction site. The pozzolanic cement composition comprises of Class C fly ash, which is a waste coming from burning of anthracite coal and the availability of such fly ashes causes an environmental concern.

[0010]

[0007] In view of the problems associated with the above state of art, there is a need to develop a high strength rapid setting concrete composition with the prolonged working time and capable of transported in large volumes over long distance.

[0011] OBJECTIVES OF THE INVENTION

[0012]

[0008] The primary objective of the present invention is to provide a high strength rapid setting concrete composition and a method for preparation thereof.

[0013]

[0009] Another objective of the present invention is to provide the high strength rapid setting concrete composition capable of being transported in large volumes over longer distances.

[0010] Yet another objective of the present invention is to provide high strength rapid setting concrete composition with prolonged working time.

[0014] [Oil] Yet another objective of the present invention is to use the composition for repairing roads or any damaged site.

[0015]

[0012] Other objectives and advantages of the present invention will become apparent from the following description taken in connection with the accompanying drawings, wherein, by way of illustration and example, the aspects of the present invention are disclosed.

[0016] SUMMARY OF THE INVENTION

[0017]

[0013] The present invention relates to a high strength rapid setting concrete composition, and a method thereof. The concrete composition comprises a cementitious material, a metal oxide / aluminate, a water reducer, an aggregate, a retarder, an accelerator, a fiber, an alkali metal salt, or a combination thereof. The cementitious material is present in the composition in 10-25% by weight of the total composition, the metal oxide / aluminate is in 10-25% by weight of the total composition, the water reducer is present in the composition in 0.01-1.5% by weight of the total composition, the aggregate is present in the composition in 12-76% by weight of the total composition, the retarder is present in the composition in 0.01-1.2% by weight of the total composition, the accelerator is present in the composition in 0.01-1.0% by weight of the total composition, the fiber is present in the composition in 0.1 -2.0% by weight of the total composition, and the alkali metal salt is present in the composition in 6-25% by weight of the total composition.

[0018]

[0014] The present invention also relates to a method of preparing the high strength rapid setting concrete composition. The method involves the preparation of a slurry by mixing a cementitious material, metal oxide / aluminates, aggregates, accelerator, and water reducer, in water for 30 minutes to 2 hour; and the preparation of a powdered mixture by mixing alkali metal salts, water reducer, retarder, accelerator and fibers.

[0019]

[0015] The concrete composition is prepared by mixing 85-95% of the slurry material along with water in ready mix concrete truck, which does not get harden for more than 2 hours and adding rest 5-15% of the powder mixture at repairing site. This concrete composition harden within 30-35 minutes after powder mixture is added to the slurry at the repairing site. This high strength rapid setting concrete composition has the prolonged working time with transportation of composition in large volumes over longer distance.

[0020]

[0016] The method involves the preparation of a slurry by mixing a cementitious material, metal aluminates, aggregate, and water reducer, in water for 30 minutes to 2 hour; and the preparation of a powdered mixture by mixing alkali metal salts, water reducer, retarder, accelerator and fibers. This high strength rapid setting concrete composition has the prolonged working time with transportation of composition in large volumes over longer distance.

[0021] BRIEF DESCRIPTION OF DRAWINGS

[0022]

[0017] The present invention will be better understood after reading the following detailed description of the presently preferred aspects thereof with reference to the appended drawings, in which the features, other aspects and advantages of certain exemplary embodiments of the invention will be more apparent from the accompanying drawing in which:

[0023]

[0018] Figure 1 illustrates a flow diagram depicting the method of preparing the concrete composition. DETAILED DESCRIPTION OF THE INVENTION

[0024]

[0019] The following description describes various features and functions of the disclosed system with reference to the accompanying figures. In the figures, similar symbols identify similar components, unless context dictates otherwise. The illustrative aspects described herein are not meant to be limiting. It may be readily understood that certain aspects of the disclosed system can be arranged and combined in a wide variety of different configurations, all of which have not been contemplated herein.

[0025]

[0020] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0026]

[0021] Features that are described and / or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and / or in combination with or instead of the features of the other embodiments.

[0027]

[0022] The terms and words used in the following description are not limited to the bibliographical meanings but are merely used to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustrative purpose only and not for the purpose of limiting the invention.

[0028]

[0023] It is to be understood that the singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise.

[0024] The phrase “high strength rapid setting concrete composition” disclosed in the present disclosure may be interchangeably used with the term “composition”.

[0029]

[0025] It should be emphasized that the term “comprises / comprising” when used in this specification is taken to specify the presence of stated features, steps or components but does not preclude the presence or addition of one or more other features, steps, components or groups thereof.

[0030]

[0026] Accordingly, the present invention relates to a high strength rapid setting concrete composition and a method for preparation thereof. Particularly, the present invention relates to a high strength rapid setting concrete composition having prolonged working time and capable of being transported in large volumes over long distances.

[0031]

[0027] In an embodiment, the high strength rapid setting concrete composition comprises of cementitious materials, metal oxides / metal aluminates, aggregates, water reducers, retarders, alkali metal salts, accelerator, fibers, or a combination thereof.

[0032]

[0028] In an exemplary embodiment, the cementitious material used in the present material may be selected from a group of hydraulic cementitious materials. In another exemplary embodiment, the hydraulic cementitious material may be selected from a group consisting of, such as, but not limited to, Portland cement, and the like. In another exemplary embodiment, the amount of cementitious material may be used in a range of 10-25% by weight of the total composition. In yet another exemplary embodiment, the cementitious material may be used in the form of power.

[0033]

[0029] Metal oxides / aluminates used in this invention to make the reaction faster. In an exemplary embodiment, the metal oxides used in the present invention may be selected from a group consisting of, such as, but not limited to, calcium oxide, aluminium oxide, magnesium oxide, sodium oxide, potassium oxide, and the like. In another exemplary embodiment, the metal oxides may be used in the form of power. In another exemplary embodiment, the metal aluminate may be selected from a group consisting of, such as, but not limited to, sodium aluminate, potassium aluminate, calcium aluminate, etc. or a combination thereof. In a preferred embodiment, calcium aluminate is used as a metal aluminate in the present invention. In yet another exemplary embodiment, the amount of metal oxide / aluminates may be used in a range of 10-30% by weight of the total composition, more preferably the metal oxide / aluminate may be used in a range of 10-25% by weight of the total composition.

[0034]

[0030] The water reducer used in the present invention to reduce the amount of water in the slurry. In an exemplary embodiment, the water reducer used in the present invention may be selected from a group consisting of, such as, but not limited to, Lignosulfonates, Polycarboxylate ethers, etc., or a combination thereof. In another exemplary embodiment, the amount of the reducing agents may be used in a range of 0.01-1.5% by weight of the total composition. In yet another exemplary embodiment, the reducing agents may be used in the form of power.

[0035]

[0031] In another exemplary embodiment, the aggregates used in the present invention may be selected from a group consisting of, such as, but not limited to, Basaltic, granite, sand, fly ash etc., or a combination thereof. In yet another exemplary embodiment, the amount of aggregates may be used in a range of 12-76%, more preferably 40-76% by weight of the total composition. In another exemplary embodiment, different aggregates may be present in different amounts such as the amount of sand may be present in a range of 12-38% by total weight of aggregates; the amount of other aggregates may be present in a range of 12-38% by total weight of aggregates. In yet another exemplary embodiment, the aggregates may be used in the form of power.

[0032] The retarders are used in the present invention to extend the working of the concrete composition. In another exemplary embodiment, the retarders used in the present invention may be selected from a group consisting of, such as, but not limited to, sodium citrate, potasium citrate, potasium tartarate, sodium tartarate, sodium borate, tartaric acid, citric acid, boric acid, humic acid, sodium tetraborate, borax, hydrocarboxylic acid, etc., or a combination thereof. . In another exemplary embodiment, the amount of retarders may be used in a range of 0.01 -1.2% by weight of the total composition. In yet another exemplary embodiment, the retarders may be used in the form of powder.

[0036]

[0033] In yet another exemplary embodiment, the alkali metal salts used in the present invention may be selected from a group consisting of, such as, but not limited to, alkali metal sulfate, alkali metal phosphate, alkali metal carbonate, etc., or a combination thereof. In yet another exemplary embodiment, the alkali metal salts used in the present invention may be selected from a group consisting of, such as, but not limited to, calcium sulfate, calcium phosphate, calcium carbonate, mono potassium phosphate, mono ammonium phosphate, or a combination thereof. In a preferred embodiment, calcium sulfate is used as the alkali metal salt in the present invention. In yet another exemplary embodiment, the alkali metal salts may be used in a percentage range of 6- 25% by weight of the total composition. In yet another exemplary embodiment, the alkali metal salts are used in form of a powder.

[0037]

[0034] In an exemplary embodiment, the accelerator used in the present invention may be selected from a group consisting of, such as, but not limited to, metal carbonate. In an exemplary embodiment, metal carbonate may be selected from a group consisting of, such as, but not limited to, lithium carbonate. In a preferred embodiment, calcium aluminate is used as a metal aluminate in the present invention. In yet another exemplary embodiment, the metal carbonate may be used in a percentage range of 0.01- 1% by weight of the total composition. In yet another exemplary embodiment, the accelerator may be used in the present invention in the form of a powder.

[0038]

[0035] The fibers are used in the present invention to increase flexural strength of the composition. In an exemplary embodiment, the fibers used in the present invention may be selected from a group c consisting of, such as, but not limited to, glass fiber, alkaline resistance fiber, polypropelene fiber, and the like. In another exemplary embodiment, the fibers may be used in a percentage range of 0.1-2% by weight of the total composition. In yet another exemplary embodiment, the fibers may be present in the form of powder.

[0039]

[0036] In an embodiment, the present invention also provides a method for the preparation of a high strength rapid setting concrete composition. The method is a two- step method that involves preparing a slurry and a powdered mixture and thereafter mixing the prepared slurry and the powdered mixture, resulting in a high strength rapid setting concrete composition. The method comprises of the following steps: i. preparing a slurry by mixing a cementitious material, metal oxides / aluminates, accelerator, aggregate, and water reducer, in water for 30 minutes to 2 hour; ii. preparing a powdered mixture by mixing alkali metal salts, water reducer, retarder, accelerator and fibers; iii. mixing 85-95% volume of slurry obtained in step (i) in a ready-mix concrete set up at a different location and may be transported to the site; iv. mixing 5-15% of the powdered mixture obtained in step (ii) with the prepared slurry in step (i) for 2-5 minutes and pouring the composition at the repairing site and leveling the surface.

[0040]

[0037] In an exemplary embodiment, the cementitious material used in the present material may be selected from a group of hydraulic cementitious materials. In another exemplary embodiment, the hydraulic cementitious material may be selected from a group consisting of, such as, but not limited to, Portland cement, and the like. In another exemplary embodiment, the amount of cementitious material may be used in a range of 10-25% by weight of the total composition. In yet another exemplary embodiment, the cementitious material may be used in the form of power.

[0041]

[0038] Metal oxides / aluminates used in this invention to make the reaction faster. In an exemplary embodiment, the metal oxides used in the present invention may be selected from a group consisting of, such as, but not limited to, calcium oxide, aluminium oxide, magnesium oxide, sodium oxide, potassium oxide, and the like. In another exemplary embodiment, the metal oxides may be used in the form of power. In another exemplary embodiment, the metal aluminate may be selected from a group consisting of, such as, but not limited to, sodium aluminate, potassium aluminate, calcium aluminate, etc. or a combination thereof. In a preferred embodiment, calcium aluminate is used as a metal aluminate in the present invention. In yet another exemplary embodiment, the amount of metal oxides / aluminates may be used in a range of 10-30% by weight of the total composition, more preferably the metal oxide / aluminate may be used in a range of 10-25% by weight of the total composition.

[0042]

[0039] In another exemplary embodiment, the water reducer used in the present invention may be selected from a group consisting of, such as, but not limited to, Lignosulfonates, Polycarboxylate ethers, etc., or a combination thereof. In another exemplary embodiment, the amount of the reducing agents may be used in a range of 0.01-1.5% by weight of the total composition. In yet another exemplary embodiment, the reducing agents may be used in the form of power.

[0043]

[0040] In another exemplary embodiment, the aggregates used in the present invention may be selected from a group consisting of, such as, but not limited to, Basaltic, granite, sand, fly ash etc., or a combination thereof. In yet another exemplary embodiment, the amount of aggregates may be used in a range of 12-76%, more preferably 40-76% by weight of the total composition. In another exemplary embodiment, different aggregates may be present in different amounts such as the amount of sand may be present in a range of 12-38% by total weight of aggregates; the amount of other aggregates may be present in a range of 12-38% by total weight of aggregates. In yet another exemplary embodiment, the aggregates may be used in the form of power.

[0044]

[0041] The retarders are used in the present invention to extend the working of the concrete composition. In another exemplary embodiment, the retarders used in the present invention may be selected from a group consisting of, such as, but not limited to, sodium citrate, potasium citrate, potasium tartarate, sodium tartarate, sodium borate, tartaric acid, citric acid, boric acid, humic acid, sodium tetraborate, borax, hydrocarboxylic acid, etc., or a combination thereof. . In another exemplary embodiment, the amount of retarders may be used in a range of 0.01 -1.2% by weight of the total composition. In yet another exemplary embodiment, the retarders may be used in the form of powder.

[0045]

[0042] In yet another exemplary embodiment, the alkali metal salts used in the present invention may be selected from a group consisting of, such as, but not limited to, alkali metal sulfate, alkali metal phosphate, alkali metal carbonate, etc., or a combination thereof. In yet another exemplary embodiment, the alkali metal salts used in the present invention may be selected from a group consisting of, such as, but not limited to, calcium sulfate, calcium phosphate, calcium carbonate, mono potassium phosphate, mono ammonium phosphate, or a combination thereof. In a preferred embodiment, calcium sulfate is used as the alkali metal salt in the present invention. In yet another exemplary embodiment, the alkali metal salts may be used in a percentage range of 6- 25% by weight of the total composition. In yet another exemplary embodiment, the alkali metal salts are used in form of a powder.

[0043] In an exemplary embodiment, the accelerator used in the present invention may be selected from a group consisting of, such as, but not limited to, metal carbonate. In an exemplary embodiment, metal carbonate may be selected from a group consisting of, such as, but not limited to, lithium carbonate. In a preferred embodiment, calcium aluminate is used as a metal aluminate in the present invention. In yet another exemplary embodiment, the metal carbonate may be used in a percentage range of 0.01- 1% by weight of the total composition. In yet another exemplary embodiment, the accelerator may be used in the present invention in the form of a powder.

[0046]

[0044] The fibers are used in the present invention to increase flexural strength of the composition. In an exemplary embodiment, the fibers used in the present invention may be selected from a group c consisting of, such as, but not limited to, glass fiber, alkaline resistance fiber, polypropelene fiber, and the like. In another exemplary embodiment, the fibers may be used in a percentage range of 0.1-2% by weight of the total composition. In yet another exemplary embodiment, the fibers may be present in the form of powder.

[0047]

[0045] In an embodiment, the high strength rapid setting concrete composition prepared in the present invention is capable of being o transported in large volumes over a longer distance and a return to service is achieved in less than 2-3 hours from the time of pouring. The composition of the present invention covers large areas in a single pour and the work may be carried out at a faster pace.

[0048]

[0046] In an embodiment, the high strength rapid setting concrete composition exhibits a compressive strength between 15 Mpa to 66 Mpa within 2 hours to 28 days.

[0049]

[0047] The present invention may be explained by way of the following exemplary embodiments for understanding the invention and should not construed to be limiting the scope of the present invention.

[0048] Examples

[0050]

[0049] The high strength rapid setting concrete composition is prepared by mixing slurry and powdered form, which comprises of the following steps: i. preparing a slurry by mixing 6000 gm of calcium aluminate, 3600 gm of portland cement, 15 kg of sand, 15 kg of granite, 150 gm of polycarboxylate ether, 190 gm of retarder, and 5.3 L of water. ii. preparing a powder mixture by mixing 2400 gm of alkali metal sulfate, 12 gm of alkali metal carbonate, 10 gm of retarder, and 8 gm of fiber. iii. mixing slurry along with water for 60 minutes; iv. adding powder mixture to slurry and mixing it for 15 minutes; and v. casting 150 mm cubes.

[0051]

[0050] The resultant concrete cubes exhibits the compressive strength of 19 Mpa within 2 hrs., 26 Mpa within 4 hrs., 38 Mpa within 24 hrs., 47 Mpa within 3 days, 58 Mpa within 7 days, and 66 Mpa within 28 days.

[0052]

[0051] Example 2:

[0053]

[0052] The quantity of each ingredients present in the composition A of the present invention is discussed in the below Table- 1.

[0054] Table-1

[0055]

[0053] Example 3:

[0056]

[0054] The quantity of each ingredients present in the composition B of the present invention is discussed in the below Table-2.

[0057] Table-2

[0058]

[0055] The present invention exhibits advantages such as transporting the concrete composition in large volumes over longer distance; having prolonged working time; having high compressive strength; and rapid return to service is achieved.

[0059]

[0056] While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

Claims

WE CLAIM:

1. A high strength rapid setting concrete composition comprising, a cementitious material, a metal oxide / aluminate, a water reducer, an aggregate, a retarder, an accelerator, an alkali metal salt, a fiber, or their combination thereof.

2. The high strength rapid setting concrete composition as claimed in claim 1, wherein, the composition comprising, i) a cementitious material in 10-25% by weight of the total composition; ii) a metal oxide / aluminate is selected from the group ranging from 10- 25%; iii) a water reducer is selected in 0.01-1.5% by weight of the total composition; iv) an aggregate in 12-76% by weight of the total composition; v) a retarder in 0.01-1.2% by weight of the total composition; vi) an accelerator in 0.01-1.0% by weight of the total composition; vii) an alkali metal salt in 6-25% by weight of the total composition, and viii) a fiber in 0.1-2.0% by weight of the total composition.

3. The high strength rapid setting concrete as claimed in claim 1, wherein the cementitious material is Portland cement.

4. The high strength rapid setting concrete as claimed in claim 1, wherein the water reducer is selected from Lignosulfonate, Polycarboxylate ether, or their combination.

5. The high strength rapid setting concrete as claimed in claim 1, wherein the aggregate is selected from Basaltic, sand, granite, fly ash, and silica.

6. The high strength rapid setting concrete as claimed in claim 1, wherein the retarder selected from sodium citrate, potasium citrate, potasium tartarate, sodium tartarate, tartaric acid, citric acid, boric acid, humic acid, sodium tetraborate, borax, hydrocarboxylic acid.

7. The high strength rapid setting concrete as claimed in claim 1, wherein the metal oxide / aluminate is selected from sodium aluminate, potassium aluminate, calcium aluminate, magnesium oxide; and the accelerator is lithium carbonate.

8. The high strength rapid setting concrete as claimed in claim 1, wherein the fiber is selected form glass fiber, alkaline resistance fiber, polypropylene fiber.

9. The high strength rapid setting concrete as claimed in claim 1, wherein the alkali metal salt is selected from calcium sulfate, calcium phosphate, calcium carbonate, sodium sulfate, sodium carbonate, potassium sulfate, mono potassium phosphate, mono ammonium phosphate, or their combination.

10. A method of preparing high strength rapid setting concrete composition as claimed in claim 1 comprising the steps of: a) preparing a slurry by mixing a cementitious material, metal oxide / aluminate, accelerator, aggregate, and water reducer, in water for 30 minutes to 2 hour; b) preparing a powdered mixture by mixing an alkali metal salt, water reducer, retarder, accelerator and fiber; c) mixing 85-95% volume of slurry obtained in step (i) in a ready-mix concrete set up at a different location and may be transported to the site;d) mixing 5-15% of the powdered mixture obtained in step (ii) with the prepared slurry in step (i) for 2-5 minutes and pouring the composition at the repairing site and leveling the surface.

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