Precast element, a pre grouted sleeve, a system and a method for joining the precast elements
Patent Information
- Application Number
- EP2023815446
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-05-30
- Filing Date
- 2023-05-26
- Publication Date
- 2025-04-09
AI Technical Summary
Current methods for joining precast elements are time-consuming, labor-intensive, and prone to inaccuracies due to the need for skilled workers and potential air spaces in grouting, leading to compromised quality and increased costs.
A system utilizing pre-grouted sleeves filled with a unique grouting material composition, sealed watertight, and equipped with a displacement mechanism to move a bar between the sleeves, where a second grouting material reacts with the initial material to form a strong bond, ensuring accurate and efficient joining of precast elements.
The system ensures a strong bond between precast elements with reduced labor and time, ensuring correct grouting and minimizing material costs, as demonstrated by the achievement of high compressive strength in the resultant grout material.
Smart Images
Figure 1.1
Abstract
Description
PRECAST ELEMENT, A PRE GROUTED SLEEVE, A SYSTEM AND A METHOD FOR JOINING THE PRECAST ELEMENTSTECHNICAL FIELD[1] The present invention relates to a system and a method for joining precast elements and more particularly, to precast elements, pre-grouted sleeves, a system and method therefore.BACKGROUND[2] Precast construction is a type of construction in which the already casted / built / confected elements are assembled and joined on site instead of building the elements such as walls, columns, beams, slabs, 3D modules, pillars and the like on-site . An important aspect of this type of construction is j oining these precast elements on site strongly and accurately. Current state of art for example patent publication numbers WO2017187451 and WO2019186600 disclose the systems and methods for joining precast elements that include the mechanisms in which two precast elements having hollow tubes positioned therein are placed adj acently and a bar is translated from one element to other through the hollow tube . In the next step, the wet mix of grouting material is inserted in the tubes for fdling the tubes and gaps completely mixed and poured / pumped on site.[3] However, the workers must be skilled in the fdling and the installer may require to compromise the quality of the grouting material and needs. Further, the methods and systems disclosed in the current state of arts are time consuming, indirectly more expensive, and even the grouting may not 100% accurate as the installer may not be able to assure that the hollow tubes are adequately fdled with the grouting material as the alignment of precast elements, insertion of the bar and grouting the tubes and gap to perfection in the structure are crucial tasks. Further it is observed that air spaces may get created in the current systems while fdling grouting material.[4] Thus, there is a need for an effective and optimized configuration by means of a product and a system for joining precast elements that ensures strong bond between the precast elements in minimum time and labor with assurance that grout is fdled correctly in every sleeve.SUMMARY OF THE INVENTION[5] In one aspect, the present invention provides a system for joining the precast elements. The system includes a first pre-grouted sleeve to be configured in a first precast element and a second pre-grouted sleeve to be configured in a second precast element. Each of the first and the second pre-grouted sleeve pre-filled with a first grouting material and closed with a watertight seal after filling the first grouting material. A bar is movably positioned in the first pre-grouted sleeve. A displacement mechanism is positioned in the first pre-grouted sleeve for moving the bar from the first pre-grouted sleeve into the second pre-grouted sleeve upto a predefined position. A plurality of material inlet openings are configured on the first and second pre-grouted sleeves for filling a second grouting material mixed with a standard cement material therein for reacting with the first grouting material to form a resultant grout material. The resultant grout material forms a strong bond with the bar thereby joining the first and second precast elements. The displacement mechanism includes a gear arrangement or a bar pulling wire connected to the bar. The first grouting material is composed of: a high-performance precision grout of about 53-57% and crushed sand of grain size 600 to 300 micron of about 42-47%. The second grouting material is composed of: a crushed sand of grain size of 600 to 300 micron of about 45-52%, crushed Sand having grain size of 1.18mm to 600micron of about 45-52%, superplasticizer admixture of about 0.5-2% and plasticised expanding grout admixture of about 0.5-1%. The ratio of the second grouting material and the standard cement material is 1:2. The standard cement material is a mixture of a cement of about 45-50% with water. The resultant grout material is composed of the first grouting material of about 20-25%, the second grouting material of about 25-30% and standard cement material of about 45-50%. The bar is positioned and configured to move between. In another embodiment, the displacement mechanism includes a first gear and a second gear. One of the first gear or the second gear has a gear access bar to rotate the gear for moving the bar from outside of the first precast element. In alternative embodiment, the displacement mechanism includes a wire connected to the bar at one end of thewire. Other end of the wire is taken out before sealing the watertight seal for pulling the bar out from the watertight seal.[6] In accordance with an embodiment, a first pre-grouted sleeve includes a first grouting material prefilled in the sleeve. A bar is movably positioned in the first pre-grouted sleeve. A displacement mechanism is positioned inside the sleeve for moving the bar. A watertight seal closes the sleeve after filling the first grouting material and positioning the bar.[7] In accordance with an embodiment, a second pre-grouted sleeve includes a first grouting material prefilled in the sleeve and a watertight seal for closing the sleeve after filling the first grouting material in the sleeve.[8] In another aspect, the present invention provides a precast element comprising at least one first pre-grouted sleeve and / or at least one second pregrouted sleeve positioned within the precast element at a predefined distance between the consecutive sleeves. The distance between the consecutive sleeves ranges between 100 mm to 750 mm. A plurality of material inlet openings are configured on a of the first and second pre-grouted sleeve that are connected with the openings of the precast element. The extra length of the PVC pipes are cut and match with the surface of the precast element. The opening configured on the precast element for each of the material inlet openings and outlet openings of the first and / or second pre-grouted sleeves are connected to the material inlet openings and outlet openings with a PVC pipes.[9] In yet another aspect, the present invention provides a method for joining at least two precast elements. The method comprising the steps of: placing a first precast element having at least one pre-filed watertight first pre-grouted sleeve and a second precast element having a at least one second pre-filled watertight pregrouted sleeve opposite to each other having a gap therebetween. The at least one first pre-grouted sleeve and the at least one second pre-grouted sleeve face each other in co-linear manner. In the next step, a bar positioned in the first pre-grouted sleeve is moved to the second pre-grouted sleeve by a displacement mechanism. The bar breaks a water seal of the first pre-grouted sleeve and the second pregrouted sleeve (while moving from the first pre-grouted sleeve to the second pre-grouted sleeve. In the next step, the broken seals are re-sealed by a sealant material. In the next step, a mix of second grouting material and a standard cement material is introduced in the first pre-grouted sleeve and the second pre-grouted sleeve through a respective material inlet openings. The second grouting material chemically reacts with the first grouting material already present in the first and second pre-grouted sleeves thereby activating the first grouting material to form a resultant material that forms a strong bond with the bar after hardening to join the precast elements. In the last step, the gap is filled with the standard grouting material. The second grouting material is introduced in the first and second pregrouted sleeve under pressure that causes turbulence effect while reacting with the first grouting material and form colloidal, homogeneous resultant grout material. The resultant grout material fills the whole volume of the first pre-grouted sleeve and the second pre-grouted sleeve.BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[0010] The detailed description is described with reference to the accompanying figures. The same numbers are used throughout the drawings to reference like features and modules.FIG. 1 illustrates a system for joining precast elements having pre-grouted sleeve in accordance with an implementation of the present disclosure;FIG. 2 illustrates a pre-grouted sleeves of the system of FIG. 1;FIG. 3 illustrates the front view of the elements of FIG. 1 in operation;FIG. 4 illustrates front view of a displacement mechanism configured in the pregrouted sleeve of FIG. 1;FIGS. 5 illustrates side view of the displacement mechanism; andFIG. 6 illustrate the front view of the precast elements of FIG. 1 in operation;FIG. 7 illustrates the front view of the precast elements of FIG. 1 after operation; andFIG. 8A-8C shows the experiment results for bar pull out test in tabular format.
[0011] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present disclosure.DETAILED DESCRIPTION OF THE INVENTION
[0012] In the following description, for purpose of explanation, specific details are set forth in order to provide an understanding of the present disclosure. It will be apparent, however, to one skilled in the art that the present disclosure may be practiced without these details.
[0013] One skilled in the art will recognize that various implementations of the present disclosure, some of which are described below, may be incorporated into a number of systems.
[0014] However, the systems and methods are not limited to the specific implementations described herein. Further, structures and devices shown in the figures are illustrative of exemplary implementations of the present disclosure and are meant to avoid obscuring the present disclosure.
[0015] Furthermore, connections between components and / or modules within the figures are not intended to be limited to direct connections. Rather, these components and modules may be modified, re-formatted or otherwise changed by intermediary components and modules.
[0016] References in the present disclosure to “one embodiment” or “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in an embodiment” or “in an implementation” in various places in the specification are not necessarily all referring to the same embodiment or implementation.
[0017] In an aspect, the present invention provides precast elements, pre-grouted sleeves, a system and method for joining the precast elements. The first and second precast element have a pre-grouted sleeve filled with a first grouting material of a unique formulation / composition in powder form positioned therein at predefined locations. The pre-grouted sleeves are sealed watertight after filling with a firstgrouting material. One of the pre-grouted sleeves includes a joining element such as a steel bar placed therein which also houses a displacement mechanism accessible from the outside of the precast element. These pre-grouted sleeves are then placed in the moulds in the precast factory and reinforcement is tied around it and concrete is casted to form the precast element. These precast elements inclusive of the pre-grouted sleeves are then transported to the construction site where they are installed together for final assembly and joining. The joining element is moved from one pre -grouted sleeve to another pre -grouted sleeve by using the displacement mechanism when the first and second precast elements are placed adjacent to each other for joining. As the joining element is moved from one pregrouted sleeve to another, the water seals of pre-grouted sleeve are broken. The second grouting mixture is introduced with agitation / by pumping in the openings of the pre-grouted sleeve that react with the grouting material present in the preinstalled pre-grouted sleeve and get strongly bonded with the joining element resulting in the joining at least two precast elements.
[0018] Referring to FIG. 1, a system (20) for joining precast elements in accordance with an embodiment of the present invention is shown. The precast elements (10, 11) to be joined with each other include at least two precast elements i.e. a first precast element (10) and a second precast element (11). The system includes at least one first pre-grouted sleeve (1) placed at a predefined location in the first precast element (10) and at least one second pre-grouted sleeve (2) placed at a predefined location in the second precast element ( 11 ) . It is understood here that number of the first and second pre-grouted sleeves (1, 2) may vary as per the height and size of the precast elements. In accordance with the present invention, it is understood here that in case of more than two precast elements are j oined with each other, the precast element positioned between the two elements includes both the first and second pre-grouted sleeves (1, 2) placed therein, bars (3) present in the precast elements and holdfast attached to the pre-grouted sleeves are not shown in the figures for sake of clarity.
[0019] Referring to FIGS. 1-7, in accordance with an embodiment of the present invention, the first pre-grouted sleeve (1) and the second pre-grouted sleeve (2) arepre-filled with a first grouting material (4, 5) respectively having a predefined composition / unique formulation. The first grouting material (4, 5) is composed of a high-performance precision grout of about 53-57% and crushed sand of grain size 600 to 300 micron of about 42-47%. in the form of dry non-shrink, flowable, high strength grout.
[0020] Referring to FIG. 2, The first pre-grouted sleeve ( 1 ) includes a first grouting material (4, 5) prefilled in the sleeve (la). A bar (3) is movably positioned in the first pre-grouted sleeve (1). A displacement mechanism (8) for moving the bar (3) positioned inside the sleeve (la) and a watertight seal (9) closes the sleeve (la) after filling the first grouting material (4) and positioning the bar (3). The second pregrouted sleeve (2) includes the first grouting material (5) prefilled in the sleeve (2a). The watertight seal (9) closes the sleeve (2a) after filling the first grouting material (5) in the sleeve (2a). The first pre-grouted sleeve (1) and the second pre-grouted sleeve (2) include a plurality of openings configured thereon. The openings include a material inlet opening (6) and an outlet opening (7). The distance between the consecutive sleeves (1, 2) ranges between 100mm to 750mm. A plurality of material inlet openings (6) and outlet openings (7) are configured on the first and second pre-grouted sleeve (1, 2) that are connected with the openings of the precast elements with a PVC pipe. The extra length of the PVC pipes are cut and matched with the even surface of the precast elements (10, 11).
[0021] In accordance with an embodiment, a plurality of material inlet openings (6) are configured on the first and second pre-grouted sleeves (1, 2) for filling a second grouting material (13) therein. The second grouting material (13) reacts and activates the first grouting material (4, 5) to form a resultant grout material (14). The resultant grout material (14) forms a strong bond with the bar (3) thereby joining the first and second precast elements (10, 11). The second grouting material (13) is composed of a crushed sand of grain size of 600 to 300 micron of about 45- 52%, crushed sand having grain size of 1.18 mm to 600 micron of about 45-52%, superplasticizer admixture of about 0.5-2% and plasticised expanding grout admixture of about 0.5-1%. The second grouting material (13) is mixed with a standard cement material before filling in the pre-grouted sleeves (1, 2). The ratioof the second grouting material (13) and the standard cement material is 1:2. The standard cement material is a mixture of a cement of about 45-50% with water. The resultant grout material (14) is composed of the first grouting material (4, 5) of about 20-25%, the second grouting material of about 25-30% and standard cement material of about 45-50%.
[0022] Referring to FIG. 4, a displacement mechanism (8) in accordance with an embodiment of the present invention is shown. The driving mechanism (8) includes a first gear (8a) and a second gear (8b). The bar is positioned and configured to move between the first gear (8a) and the second gear (8b). One of the first gear (8a) and the second gear (8b) has a gear access bar (8c) to rotate the gear (8a, 8b) for moving the bar from the outer side of the precast element. It is to be noted here that the gears (8a, 8b) enable the bar (3) to remain at a predefined distance from the bottom portion of the first pre-grouted sleeve and the second pre-grouted sleeve (1, 2). In an embodiment, the predefined distance is the diameter of the first gear (8a) or the second gear (8b). This configuration assures covering the whole surface of the bar (3) by the resultant grout material and form a strong bond.
[0023] Referring to FIG. 5, a displacement mechanism in accordance with another embodiment includes a wire (16) connected to the bar (3). The wire (16) is connected to the bar (3) at one end of the wire (16) and other end of the wire (16) is taken out from the watertight seal (9) before sealing. It is to be noted here, that the bar (3) is pulled by the wire (16) for moving the bar (3) from the first pregrouted sleeve (1) to the second pre-grouted sleeve (2). It is to be noted here that the bar (3) is moved by the displacement mechanism from the first pre-grouted sleeve (1) to the second pre-grouted sleeve (2) upto predefined position, such that both the sleeves (1, 2) contain half length of the bar (3) after completion of the movement.
[0024] Referring to FIGS. 1-7, in operation, in first step, the first precast element (10) and a second precast element (11) are placed adjacent to each other having a gap (12) therebetween. The first and second precast elements (10, 11) are placed such that the openings of each first pre-grouted sleeve (1) and the second pregrouted sleeve (2) oppose each other. In the next step, the bar (3) is moved fromthe first pre-grouted sleeve (1) to the second pre-grouted sleeve (2) by the displacement mechanism (8). In this step, while moving out from the first pregrouted sleeve (1), the bar (3) breaks the water seal (9) of the first pre-grouted sleeve (1) and while moving inside the second pre-grouted (2), the water seal (9) of the second pre-grouted sleeve (2) is broken. Pre-grouted sleeves (1, 2) contain the first grouting material having a predefined composition / unique formulation. In the next step, the broken seals (9) are re-sealed by sealant material such as silicon or polyurethane. In the next step, second grouting material (13) having a predefined composition is introduced by agitation or by pumping in the first pre-grouted sleeve (1) and the second pre-grouted sleeve (2) through the respective material inlet openings (6). The second grouting material (13) is composed of silica sand, admixture chemicals which ensure plasticity / flowability and non-shrink behavior, a predefined amount of cement and water. In this embodiment, the second grouting material (13) is introduced in the first and second pre-grouted sleeve (1, 2) by using a suction / agitator pump (15). The second grouting material (13) is mixed with a standard cement material before introducing in the pre-filled pre-grouted sleeves (1, 2). The second grouting material (13) chemically reacts with the first grouting material (4, 5) already present in the first and second pre-grouted sleeve (1, 2) thereby activating the first grouting material (4, 5). It is to be noted here that the second grouting material (13) is introduced in the first and second pre-grouted sleeve (1, 2) at a predefined pressure that causes turbulence effect while reacting with the first grouting material (4, 5) and form colloidal, homogeneous resultant grout material (14). The resultant grout material (14) fills the whole volume of the first pre-grouted sleeve (1) and the second pre-grouted sleeve (2). In the next step, the resultant material (14) is hardened thereby forming a strong bond with the bar (3). In the last step, the gap (12) is filled with the standard grouting material. It is to be noted here that the first grouting material (4, 5) and the second grouting material (13) have a unique composition such that despite of having different densities and viscosities, form a colloidal state after getting mixed with each other to form a homogeneous strong adhesive mixture.
[0025] Advantageously, the present invention ensures correct grouting, by means of measured material and processes. The present invention saves time required for the grouting on-site. Further, the installer does not have to depend on 100% proprietary material such as grout. Almost 50% of the materials used in the present invention is standard cement, that reduces cost of the product. The method of the present invention is also envisaged to save manpower for grouting, due to the use of per-packet-mix-ratio and usage ofthe specially designed pump. Further, grouting the gap separately is easier for the Installer, since this is already a prevalent practice, and no new method or materials need to be adopted. The present invention provides a standard ready-made product which the Installer just have to fix to the reinforcement and the mould side which saves time spent on labor / assembly and fixing etc. at the time of casting / confection of the precast elements as briefly described in preceding paragraphs.
[0026] Example:Referring to FIG. 8A-8C, a pull-out test for checking the reliability of the system of the present invention was conducted. The bonding of the bar (3) with the resultant material (14) after hardening was tested by conducting a bar pull out test. In this test the bar (3) was pulled out from the precast element (10, 11) after completion 14 days (FIG. 8A) and 28 days (FIG. 8B) of grouting. It was observed that on completion of 14 days; resultant grout material (14) got 50+MPa strength and further on completion of 28 days the resultant grout material (14) achieved 60+MPa strength. It was observed that all the bars (3) got cut without any failure of bond between bar (3), resultant grout material (14) and pre-grouted sleeve (1, 2).
[0027] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.
Claims
Claims :
1. A system for joining the precast elements, the system comprising: a first pre-grouted sleeve (1) to be configured in a first precast element (10) and a second pre-grouted sleeve (2) to be configured in a second precast element (11), each of the first and the second pre-grouted sleeve (1, 2) pre-filled with a first grouting material (4, 5) and closed with a watertight seal (9) after filling the first grouting material (4, 5); a bar (3) movably positioned in the first pre-grouted sleeve (1); a displacement mechanism (8) positioned in the first pre-grouted sleeve (1) for moving the bar (3) from the first pre-grouted sleeve (1) into the second pre-grouted sleeve (2) up to a predefined position; and a plurality of material inlet openings (6) and an outlet openings (7) configured on the first and second pre-grouted sleeves (1, 2), the inlet openings (6)provided for filling a second grouting material (13) and a standard cement material in the first and second pre-grouted sleeves (1, 2) for reacting with the first grouting material (4, 5) to form a resultant grout material (14), the resultant grout material (14) forms a strong bond with the bar (3) for joining the first and second precast elements (10, 11).
2. The system as claimed in claim 1, wherein the first grouting material (4, 5) is composed of: a high-performance precision grout of about 53-57% and crushed sand of grain size 600 to 300 micron of about 42-47%.
3. The system as claimed in claim 1, wherein the second grouting material (13) is composed of: a crushed sand of grain size of 600 to 300 micron of about 45-52%, crushed sand having grain size of 1.18mm to 600micron of about 45-52%, superplasticizer admixture of about 0.5-2% and plasticised expanding grout admixture of about 0.5-1%.
4. The system as claimed in claims 1-3, wherein the ratio of the second grouting material (13) and the standard cement material is 1:2.
5. The system as claimed in claims 1- 4, wherein the standard cement material is a mixture of a cement of about 45-50% with water.
6. The system as claimed in claim 1, wherein the resultant grout material (14) is composed of the first grouting material (4, 5) of about 20-25%, the second grouting material of about 25-30% and standard cement material of about 45-50%.
7. The system as claimed in claim 1, wherein the displacement mechanism (8) includes a first gear (8a) and a second gear (8b) for positioning the bar (3) movably therebetween and a gear access bar (8c) for rotating one of the first gear (8a) and the second gear (8b) for moving the bar (3) from the first precast element (10).
8. The system as claimed in claim 1, wherein the displacement mechanism (8) includes a wire (16) connected to the bar (3) at one end of the wire (16), other end of the wire (16) is taken out before sealing the watertight seal (9) for pulling the bar (3) out from the first pre-grouted sleeve (1).
9. A first pre-grouted sleeve (1) comprising: a first grouting material (4) prefilled in the sleeve (la); a bar (3) movably positioned in the first pre-grouted sleeve (1); a displacement mechanism (8) for moving the bar (3) positioned inside the sleeve (la); and a watertight seal (9) for closing the sleeve (la) after filling the first grouting material (4) and positioning the bar (3).
10. A second pre-grouted sleeve (2) comprising: a first grouting material (5) prefilled in the sleeve (2a); and a watertight seal (9) for closing the sleeve (2a) after filling the first grouting material (5) in the sleeve (2a).
11. A precast element (10, 11) comprising:at least one first pre-grouted sleeve (1) as claimed in claim 9 and / or at least one second pre-grouted sleeve (2) as claimed in claim 10 positioned within the precast element (10, 11) at a predefined distance between the consecutive sleeves (1, 2); and an opening configured on the precast element (10, 11) for each of the material inlet openings (6) and outlet openings (7) of the first and / or second pre-grouted sleeves (1, 2), said openings are connected to the material inlet openings (6) and outlet openings (7) with a PVC pipes.
12. A method for joining at least two precast elements (10, 11), the method comprising the steps of: placing a first precast element (10) having at least one pre-filed watertight first pre-grouted sleeve (1) and a second precast element (11) having at least one second pre-filled watertight pre-grouted sleeve (2) opposite to each other having a gap (12) therebetween, the at least one first pre-grouted sleeve (1) and the at least one second pre-grouted sleeve (2) face each other in co-linear manner; moving a bar (3) positioned in the first pre-grouted sleeve (1) to the second pre-grouted sleeve (2) by a displacement mechanism (8), the bar (3) breaks a water seals (9) of the first pre-grouted sleeve (1) and the second pre-grouted sleeve (2) while moving from the first pre-grouted sleeve (1) to the second pre-grouted sleeve (2); re-sealing the broken seals (9) by a sealant material; introducing a mix of second grouting material (13) and a standard cement material in the first pre-grouted sleeve (1) and the second pre-grouted sleeve (2) through a respective material inlet openings (6), the second grouting material (13) chemically reacts with the first grouting material (4, 5) already present in the first and second pre-grouted sleeves (1, 2) thereby activating the first grouting material (4, 5) to form a resultant material (14) that hardens and forms a strong bond with the bar (3) to join the precast elements (10, 11); and filling the gap (12) with the standard grouting material.
13. The method as claimed in claim 12, wherein the second grouting material (13) is introduced in the first and second pre-grouted sleeve (1, 2) at a predefined pressure that causes turbulence effect while reacting with the first grouting material (4, 5) and form colloidal, homogeneous resultant grout material (14).
14. The method as claimed in claim 12, wherein the resultant grout material (14) fills the whole volume of the first pre-grouted sleeve (1) and the second pre-grouted sleeve (2).