Description:FIELD OF INVENTION
[001] The present invention relates to a high strength rapid setting concrete composition. Particularly, the present invention relates to the two-part high strength rapid setting concrete composition able to transport over long distances. More particularly, the present invention relates to a method of preparing two-part high strength rapid setting concrete composition having prolonged working time.

BACKGROUND OF THE INVENTION

[002] The quick setting concrete composition predominantly used for rapid repairs of concrete structures or roads, are generally supplied in pre-packed bags either in 25 kg or 50 kg. 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.

[003] 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.
[004] 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.

[005] 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.

[006] 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.

[007] 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 transportation of composition in large volumes over longer distance.

OBJECTIVES OF THE INVENTION

[008] The primary objective of the present invention is to provide a high strength rapid setting concrete composition.

[009] Another objective of the present invention is to provide the two-part high strength rapid setting concrete composition able to transport in large volumes over longer distances.

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

[011] Yet another objective of the present invention is to provide a method of preparation of two-part high strength rapid setting concrete composition.

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

[013] 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.

SUMMARY OF THE INVENTION

[014] The present invention relates to a method of preparing a high strength rapid setting concrete composition. This high strength rapid setting concrete composition is prepared in two-parts (Part A and Part B) by mixing 85-95% of the 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 material at repairing site. This concrete composition harden within 30-35 minutes after part B is added to part A at the repairing site. Part A of the concrete composition is prepared from a mixture of hydraulic cements, metal oxides, sand, aggregate, water reducer, retarders, and water and part B of the concrete composition is prepared from a mixture of alkali metal sulfates, carbonates or phosphates, retarder, and fibers.

BRIEF DESCRIPTION OF DRAWINGS
[015] 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:

DETAILED DESCRIPTION OF THE INVENTION

[016] 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.

[017] 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.

[018] 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.

[019] 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.

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

[021] 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.

[022] Accordingly, the present invention relates to a high strength rapid setting concrete composition. Particularly, the present invention relates to the high strength rapid setting concrete composition able to transport over long distances. More particularly, the present invention relates to a method of preparing the high strength rapid setting concrete composition having prolonged working time.

[023] In an embodiment, the method of preparation of a high strength rapid setting concrete composition comprises the following steps:
i. preparing slurry form mixture of Part A of concrete composition by mixing hydraulic cements, metal oxides, sand, aggregate, water reducer, retarder 1, retarder 2, and water;
ii. preparing powder form mixture of Part B of concrete composition by mixing alkali metal carbonates, sulfates, or phosphates, retarder 2, and fibers;
iii. mixing 85-95% of the volume of slurry mixture of Part A of concrete composition in a ready-mix concrete set up for the required volume at a different location and may be transported to the site;
iv. mixing 5-15% of Part B powder of concrete composition with Part A for 2-5 minutes before pouring the composition at repairing site and levelling the surface.

[024] In an exemplary embodiment, hydraulic cements of Part A of concrete composition may be selected from a group consisting of, such as, but not limited to, Portland cement.

[025] In an exemplary embodiment, metal oxides of Part A of concrete composition may be selected from a group consisting of, such as, but not limited to, Calcium Aluminate.

[026] In an exemplary embodiment, water reducer of Part A of concrete composition may be selected from a group consisting of, such as, but not limited to, Lignosulfonates, and Polycarboxylate ethers.

[027] In an exemplary embodiment, aggregate of Part A of concrete composition may be selected from a group consisting of, such as, but not limited to, Basaltic and granite.

[028] In an exemplary embodiment, retarder 1 of concrete composition may be selected from a group consisting of, such as, but not limited to, Sodium Citrate, Potasium Citrate, Potasium tartarate, Sodium Tartarate, and Sodium borate.

[029] In an exemplary embodiment, retarder 2 of concrete composition may be selected from a group consisting of, such as, but not limited to, tartaric acid, citric acid, boric acid, humic acids, and sodium tetraborate.

[030] In an embodiment, the high strength rapid setting concrete composition is able to transport 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 present invention covers large areas in a single pour and the work may be carried out at a faster pace.

[031] In an embodiment, the rapid setting concrete composition have a compressive strength of more than 15 Mpa to 66 Mpa within 2 hours to 28 days.

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

[033] The high strength rapid setting concrete composition is prepared by mixing Part A and Part B comprises the following steps:
i. preparing slurry form mixture of Part A of concrete composition 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, 180 gm of retarder 1, 10 gm of retarder 2, and 5.3 L of water.
ii. preparing powder form mixture of Part B of concrete composition by mixing 2400 gm of Alkali metal sulfate, 12 gm of Alkali metal carbonate, 10 gm of retarder 2, and 8 gm of fiber.
iii. mixing part A along with water for 60 minutes;
iv. adding Part B to Part A slurry and mixed it for 15 minutes; and
v. casting 150 mm cubes.

[034] The resultant concrete cubes have 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.

[035] 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.

[036] While the present invention has been described with reference to one or more preferred aspects, which also have been set forth in considerable detail for the purposes of making a disclosure of the invention, such aspects are merely exemplary and are not intended to be limiting or represent an exhaustive enumeration of all aspects of the invention. The scope of the invention, therefore, shall be defined solely by the claims, which will be followed in the complete specification to be filed at a later stage. Further, it will be apparent to those of skill in the art that numerous changes may be made in such details without departing from the principles of the invention.
, Claims: