Embedded part, self-balancing correction system and continuous concrete pouring construction method

Abstract

The invention provides an embedded part, a self-balance correction system and a continuous pouring concrete construction method, relates to the technical field of buildings, and aims to solve the technical problem that cracks of a joint surface of new and old concrete are difficult to control. The embedded part comprises a plurality of restraining parts, and each restraining part comprises a frame structure and a plurality of first rods; the frame structure comprises a plurality of second rods, and the middle portions of the second rods intersect at the center point of the frame structure. Each first rod is perpendicular to the frame structure and connected to the free end of the corresponding second rod. In every two adjacent restraining pieces, the end of the first rod of one restraining piece is connected with the end of the corresponding first rod of the other restraining piece, the free ends of the second rods intersect at the centers of the first rods, and the multiple second rods are evenly distributed in the circumferential direction of the frame structure. The embedded part is used for interface crack control of a concrete pouring part and an old concrete member, control is efficient and low in consumption, the construction process is simple, and operability is high.

Description

Technical Field

[0001] The invention relates to the technical field of construction, and in particular to an embedded part, a self-balancing correction system, and a continuous pouring concrete construction method. Background Art

[0002] In the continued construction project, it is necessary to cut off the severely damaged concrete components and then cast them again to ensure the integrity and safety of the entire structure, while restoring or improving the bearing capacity and durability of the components. Since the hydration reaction of the old concrete has been basically completed, while the hydration reaction of the new concrete has just begun. Before hardening, the new concrete decreases in volume due to the rapid evaporation of water, but the old concrete does not shrink synchronously. Therefore, shear or tensile cracks are formed at the interface between the new and old concrete, affecting the mechanical properties of the concrete components.

[0003] In the related technologies, crack control by layered and block casting method requires a long time to wait for the upper part of concrete to condense to a certain degree before continuing construction, which is time-consuming; the water cooling method requires a large amount of water and electricity resources, and the cost is out of control; the water temperature and water volume, layer height, and block height-to-width ratio are all key parameters that are difficult to control. Summary of the invention

[0004] The purpose of the present invention is to provide an embedded part, a self-balancing correction system and a continuous pouring concrete construction method to solve the technical problem that cracks on the joint surface of new and old concrete are difficult to control.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides an embedded component for controlling interface cracks of a concrete casting, wherein the embedded component comprises a plurality of restraining components, and the restraining components comprise a frame structure and a plurality of first rods;

[0007] The frame structure includes a plurality of second rods, and the middle parts of the plurality of second rods intersect at the center point of the frame structure;

[0008] Each of the first rods is perpendicular to the frame structure and connected to a free end of a corresponding second rod;

[0009] Among two adjacent restraining members, the end of the first rod of one restraining member is connected to the end of the corresponding first rod of the other restraining member.

[0010] According to at least one embodiment of the present invention, the free ends of the second rods intersect at the center of the first rods.

[0011] According to at least one embodiment of the present invention, a plurality of the second rods are evenly arranged along the circumference of the frame structure.

[0012] According to at least one embodiment of the present invention, the connection between the first rods in two adjacent restraining members is welding or a detachable connection.

[0013] According to at least one embodiment of the present invention, two ends of the first rod are respectively provided with connecting plates, and the connecting plates are located on a side of the first rod away from the frame structure;

[0014] The connecting plates of the two first rods are connected by bolts.

[0015] According to at least one embodiment of the present invention, the length of the first rod is less than or equal to 50 cm.

[0016] According to at least one embodiment of the present invention, the free end of the second rod extends out of the casting, and the distance between the free end of the second rod and the surface of the casting is in the range of 2 cm to 5 cm.

[0017] In a second aspect, the present invention further provides a self-balancing correction system, comprising a controller, a heating device, a plurality of displacement sensors and the embedded part described in the first aspect;

[0018] Each of the displacement sensors is disposed at the free end of the corresponding first rod of the restraining member located at the top end;

[0019] The heating device and the displacement sensor are both electrically connected to the controller, and the heating device is used to increase the temperature of the first rod.

[0020] In a third aspect, the present invention further provides a method for continuous pouring of concrete, using the self-balancing correction system described in the second aspect, the method comprising:

[0021] Determining the size of the restraining member according to the size of the casting member, wherein the size of the restraining member includes the pre-compression amount of the second rod;

[0022] Assembling the self-balancing correction system and providing a supporting template around the restraining member;

[0023] Concrete is poured in the supporting formwork.

[0024] According to at least one embodiment of the present invention, after pouring concrete in the support formwork, the construction method further includes:

[0025] The first rod is removed, and the portion of the second rod extending beyond the cast part is removed.

[0026] Among the one or more technical solutions provided in the exemplary embodiments of the present invention, at least one of the following beneficial effects can be achieved.

[0027] The embedded part of the exemplary embodiment of the present invention is formed by connecting a plurality of restraints in sequence, and the restraints are formed by a frame structure formed by crossing a plurality of second rods, wherein the second rods are perpendicular to the plane where the frame structure is located and connected to the free ends of the second rods, and two adjacent restraints are connected by the second rods, that is, the plurality of second rods are located on the peripheral side of the restraints, and the frame structure restrains the plurality of second rods together. The second rod is made of nickel-titanium shape memory alloy, the first rod is made of iron-based shape memory alloy, and the second rod has a certain amount of pre-compression. When the embedded part is set in the newly poured concrete, after the concrete is poured and during the complete condensation process, the concrete undergoes a hydration heat reaction, and the internal temperature of the concrete rises sharply to the recovery temperature of the nickel-titanium shape memory alloy of the second rod. Under the action of the recovery temperature, the nickel-titanium shape memory alloy of the second rod generates an outward stress that recovers from a compressed state to an elongated state, and reaches a balance with the inward stress of the concrete heated and contracted, so that the continued concrete will not produce cracks at the interface of the new and old concrete due to shrinkage. Based on this, the embedded parts of the exemplary embodiment of the present invention can efficiently control the shrinkage cracks at the interface between the newly poured concrete and the old concrete components with low consumption, simple construction process and high operability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings illustrate exemplary embodiments of the present invention and together with the description serve to explain the principles of the present invention, and these drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification;

[0029] Figure 1 is a schematic structural diagram of embedded parts and some cast parts according to an embodiment of the present invention;

[0030] Figure 2 is a schematic diagram of an axonometric structure of a restraining member according to an embodiment of the present invention;

[0031] Figure 3 Schematic diagram of the structure of a self-balancing correction system according to an embodiment of the present invention.

[0032] Reference numerals:

[0033] 11. First rod; 12. Second rod; 13. Connecting plate; 20. Casting; 30. Displacement sensor; 40. Controller; 50. Relay; 60. Power supply. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0035] In order to achieve the control of cracks on the interface of continued concrete pouring, the related technologies have the problems of low control efficiency of concrete cracks, large human influence, low degree of automation or unstable control. For the continued pouring of concrete components in the basement environment of unfinished continued construction projects, the construction period of the continued construction project is usually short. The common layered and block casting method requires that each layer of concrete be poured before initial setting, and its construction efficiency is very limited. In addition, the basement environment is relatively narrow, and the concrete supply, transportation and construction organization of the layered and block casting method are very inconvenient. When faced with the continued pouring of large-volume concrete beam and column components, the above-mentioned various restrictions are more prominent. The control of concrete cracks in the related technologies is mainly aimed at the control of bending cracks in components, and does not pay attention to the control of self-shrinkage cracks after the pouring of new concrete.

[0036] In response to the above problems, the embedded parts provided by the exemplary embodiment of the present invention are made of shape memory alloy materials (SMA), which can passively receive the hydration heat after concrete pouring and generate recovery stress to achieve constrained control of cracks. The control of cracks is carried out synchronously with the pouring and condensation process of concrete, and the excitation heat energy of the SMA material is provided by the concrete hydration heat process. The crack control efficiency is high and there is no large consumption of resources.

[0037] Figure 1 is a schematic structural diagram of embedded parts and some cast parts according to an embodiment of the present invention; Figure 2 Schematic diagram of the isometric structure of a restraining member according to an embodiment of the present invention. Figure 1 and Figure 2 As shown, the embedded parts provided by the exemplary embodiment of the present invention include multiple constraints, and the constraints include a frame structure and multiple first rods 11; the frame structure includes multiple second rods 12, and the middle parts of the multiple second rods 12 intersect at the center point of the frame structure; each first rod 11 is perpendicular to the frame structure and connected to the free end of the corresponding second rod 12; in two adjacent constraints, the end of the first rod 11 of one constraint is connected to the end of the corresponding first rod 11 of the other constraint.

[0038] In some embodiments, the free ends of the second rods 12 intersect at the center of the first rod 11; and a plurality of second rods 12 are evenly arranged along the circumference of the frame structure.

[0039] The number of the second rods 12 of the constraint member can be two, three or more, depending on the shape of the concrete casting 20 and the direction of the required stress control. The cross section of the casting 20 can be rectangular, square or circular, etc. The angle between the second rods in the constraint member can be 90°, 60°, 45°, 30°, etc. For the convenience of description, the present invention is described by taking the number of the second rods 12 as two and the casting 20 as a concrete column with a square cross section as an example.

[0040] The two second rods 12 are arranged in a cross shape, and the two free ends of each second rod 12 correspond to two opposite side surfaces of the casting member 20 respectively. Each restraining member has four first rods 11 in total.

[0041] like Figure 1 As shown, the embedded part includes constraint members connected in sequence from high to low, and the first rods 11 of each constraint member located on the same side of the casting 20 are connected in sequence to form a long rod substantially the same height as the casting 20. Exemplarily, the height of the long rod is slightly greater than the height of the casting 20.

[0042] Specifically, the connection between the two connected first rods 11 of different restraining members may be a welding connection or a detachable connection.

[0043] For example, a connecting plate 13 is provided at both ends of the first rod 11, and the connecting plate 13 is located on the side of the first rod 11 away from the frame structure; the connecting plates 13 of the two first rods 11 are connected by bolts. Through this detachable connection, the number of restraints can be determined according to the height of the actual casting 20, thereby facilitating assembly.

[0044] For example, the size of the casting 20 is length*width*height=b*w*h, the length of each first rod 11 of the constraint is h / n, n is the number of constraints, and to ensure the uniformity of concrete shrinkage constraint, h / n should not be greater than 50 cm.

[0045] In order to facilitate the connection between the free end of the second rod 12 and the first rod 11, the free end of the second rod 12 extends out of the casting 20, and the distance between the free end of the second rod 12 and the surface of the casting 20 ranges from 2cm to 5cm, such as 3cm, 4cm, etc.

[0046] Exemplarily, the first rod 11 and the second rod 12 are connected by welding; optionally, the first rod 11 and the second rod 12 are connected by epoxy resin, for example, the epoxy resin can be SW-70 tetrafunctional epoxy resin. Therefore, after the casting 20 is finalized, the connection between the second rod 12 and the first rod 11 can be disconnected only by chemical sol, so that the frame structure formed by the second rod 12 is retained in the casting 20. At the same time, when the first rod 11 is heated up by power-on to correct the deformation, due to the insulation of epoxy resin, the first rod 11 heated up by power-on will not affect the second rod 12, thereby avoiding deformation inside the casting 20 due to the shape change and mechanical property change of the second rod 12.

[0047] For example, the material of the first rod 11 is Fe-Mn-Si iron-based shape memory alloy, which has the characteristics of high rigidity and high thermal sensitivity to support the entire embedded part and subsequent shape recovery. At the same time, its high thermal sensitivity can achieve deformation recovery of the long rod formed by multiple first rods only through a small current, and then provide a force to restrain the excessive extension of the second rod 12 through the long rod, with less resource consumption.

[0048] Exemplarily, the material of the second rod 12 is a nickel-titanium shape memory alloy, such as TiNi-02 nickel-titanium shape memory alloy, which has a thermal expansion coefficient similar to that of concrete, thereby minimizing insufficient or excessive deformation caused by excessive difference in thermal expansion coefficient. The temperature generated by the hydration heat of the concrete meets the material recovery temperature requirement of the second rod 12, thereby efficiently utilizing the hydration heat energy to constrain concrete shrinkage cracks, improving efficiency while saving energy.

[0049] Considering that the tensile stress generated by the second rod 12 under the action of the heat of concrete hydration and the shrinkage stress of the concrete are balanced as much as possible, the second rod 12 needs to be pre-compressed along its length direction, and the pre-compression amount is ΔL. The above stress balance depends on the length of the second rod 12 recovered by heat, the cross-sectional area, the magnitude of the generated recovery stress, and the size and volume of the concrete. The pre-compression amount is ΔL determined by Formula 3.

[0050]

[0051] Q = ηCV, formula 2;

[0052]

[0053] Among them, σ T represents the restoring force of the second rod 12 at the maximum hydration heat temperature of concrete, A represents the cross-sectional area of ​​the second rod 12, V represents the volume of the casting 20, Q represents the magnitude of the hydration heat, L represents the original length of the second rod 12, ε represents the shrinkage coefficient of concrete, and K represents the stress equilibrium coefficient. The magnitude of the hydration heat Q of concrete is further expressed as a relationship with the cement hydration heat coefficient η and the amount of cement C in a unit volume of concrete, as shown in Formula 2.

[0054] Exemplarily, the first rod 11 and the second rod 12 are circular rods. To ensure the shrinkage restraining effect of concrete, the diameter of the second rod 12 is 1 / 40*max{b, h}, where b is the length of the cross section of the casting 20 and h is the height of the casting 20.

[0055] Figure 3 Schematic diagram of the structure of the self-balancing correction system according to an embodiment of the present invention. Figure 3As shown, an exemplary embodiment of the present invention provides a self-balancing correction system, including a controller 40, a heating device, a plurality of displacement sensors 30 and the embedded parts of the above-mentioned embodiment; each displacement sensor 30 is arranged at the free end of the corresponding first rod 11 of the constraint member located at the top; the heating device and the displacement sensor 30 are electrically connected to the controller 40, and the heating device is used to heat the first rod 11.

[0056] In practical applications, the heating device includes a relay 50 and a power supply 60. Four displacement sensors 30 are respectively arranged at the top of four long rods (formed by the first rod 11 of multiple restraining members) to monitor the displacement of the four long rods. Exemplarily, the displacement sensor 30 is a laser displacement meter, which is bonded to the top of the long rod using epoxy resin gel. When the displacement change of the long rod monitored by it exceeds 3mm, the controller 40 (PLC programmable logic controller) electrically connected thereto sends a signal to the relay 50 to close it. The relay 50 is connected to the power supply 60. After closing, the first rod 11 is electrically heated through the electric clamp, so that it deforms and returns to a vertical state.

[0057] Exemplarily, the self-balancing correction system also includes a thermocouple sensor provided on each first rod 11, which is used to monitor the thermal power and heating time of the first rod 11. The thermocouple sensor is also electrically connected to the programmable logic controller PLC to adjust the amount of power supplied to ensure that the first rod 11 reduces the power or cuts off the power in time after reaching sufficient heat and restoring its shape to avoid overheating.

[0058] The exemplary embodiment of the present invention further provides a construction method for continuous pouring of concrete, using the self-balancing correction system of the above embodiment, wherein the construction method comprises:

[0059] Step 101: Properly clean the old concrete surface by roughening and moistening it.

[0060] Step 102 : Determine the size of the constraint member according to the size of the casting member 20 , wherein the size of the constraint member includes the pre-compression amount of the second rod 12 .

[0061] According to the size of the casting 20, the number of restraints in the embedded parts, the length of the first rod 11, the length of the second rod 12, the diameters of the first rod 11 and the second rod 12, and the pre-compression amount of the second rod 12 calculated according to Formula 3 are determined.

[0062] Step 103: Assemble the self-balancing correction system and set a supporting template around the restraining member.

[0063] According to the size of the embedded parts, a hole is made in the support formwork at the intersection of the support formwork and the second rod 12, so that the free end of the second rod 12 extends out of the support formwork, the first rods 11 of each constraint are installed, and the corresponding first rods 11 are connected to form a long rod. Specifically, the connection between the first rods 11 is connected by the connecting plate 13 and the bolts and nuts on the connecting plate 13.

[0064] A displacement sensor 30 is installed at the top of the long rod formed by the first rod 11 to construct a self-balancing correction system; the bottom end of the long rod is grounded to the ground through bolts to provide support force.

[0065] Step 104: Pour concrete into the support formwork.

[0066] Step 1041 : During the period from the completion of concrete pouring to the complete condensation process, the concrete undergoes a hydration heat reaction, and the temperature inside the concrete rises sharply to reach the shape recovery temperature of the second rod 12 .

[0067] Step 1042: Under the effect of the recovery temperature, the outward stress of the second rod 12 recovering from the compression state to the extension state reaches a balance with the inward stress of the concrete shrinking due to heating, so that the concrete will not shrink and produce cracks.

[0068] Step 1043: When the stress equilibrium state is broken, the second rod 12 continues to extend, and the laser displacement meter detects that the long rod formed by the first rod 11 has a top displacement that is too large, for example, greater than 3 cm, due to the excessive extension of the second rod 12 .

[0069] Step 1044: The programmable logic controller PLC recognizes the change in the laser displacement count value, closes the relay 50, and enables the power supply 60 to energize and heat the first rod 11.

[0070] Step 1045: The relay 50 introduces current into the long rod through the electric clamp, forcing it to return to its original vertical upright state, thereby generating a force that balances the excess outward stress of the second rod 12, preventing the second rod 12 from continuing to extend and causing friction damage to the edge concrete.

[0071] Step 1046: When the thermocouple sensor detects that the long rod has reached the recovery temperature and the laser displacement count value no longer changes, the PLC controls the relay 50 to cut off the power.

[0072] Step 1047: After the newly poured concrete has finished solidifying, remove the self-balancing correction system and supporting formwork in sequence.

[0073] Step 105 : dismantle the first rod 11 , and remove the portion of the second rod 12 extending out of the casting 20 .

[0074] Specifically, the first rod 11 of the embedded part can be removed and reused repeatedly, and the second rod 12 in the concrete body cuts off the protruding part relative to the concrete surface, and the other part continues to remain in the casting, which can improve the mechanical properties of the concrete to a certain extent.

[0075] As can be seen from the above, the self-balancing correction system provided by the exemplary embodiment of the present invention can avoid the situation where the second rod is excessively extended due to improper design of the second rod, large error in the estimation of concrete hydration heat, etc., resulting in friction damage to the edge of the concrete. The self-balancing control is achieved through the interaction of PLC, displacement sensor and temperature sensor. The entire control process has a high degree of automation, precise control, and is extremely safe and efficient.

[0076] The construction method of the exemplary embodiment of the present invention achieves effective control of shrinkage cracks of new and old concrete, is convenient and quick, and the entire system has high safety, high degree of automation and low resource consumption.

[0077] Other technical advantages of the above construction method over the prior art are the same as those of the above self-balancing correction system, which will not be described in detail here.

[0078] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present invention.

Claims

1. An embedded part, characterized in that: Used for controlling interface cracks of concrete castings, the embedded parts include a plurality of restraining parts, and the restraining parts include a frame structure and a plurality of first rods; The frame structure includes a plurality of second rods, and the middle parts of the plurality of second rods intersect at the center point of the frame structure; Each of the first rods is perpendicular to the frame structure and connected to a free end of a corresponding second rod; Among two adjacent restraining members, the end of the first rod of one restraining member is connected to the end of the corresponding first rod of the other restraining member.

2. The embedded part according to claim 1, characterized in that: The free ends of the second rods intersect at the center of the first rods.

3. The embedded part according to claim 1, characterized in that: A plurality of the second rods are evenly arranged along the circumference of the frame structure.

4. The embedded part according to claim 1, characterized in that: The connection between the first rods in two adjacent restraining members is welding or a detachable connection.

5. The embedded part according to claim 4, characterized in that: Both ends of the first rod are respectively provided with connecting plates, and the connecting plates are located on a side of the first rod away from the frame structure; The connecting plates of the two first rods are connected by bolts.

6. The embedded part according to any one of claims 1 to 5, characterized in that: The length of the first rod is less than or equal to 50 cm.

7. The embedded part according to claim 6, characterized in that: The free end of the second rod extends out of the casting, and the distance between the free end of the second rod and the surface of the casting is in the range of 2 cm to 5 cm.

8. A self-balancing correction system, characterized in that: It comprises a controller, a heating device, a plurality of displacement sensors and the embedded part according to any one of claims 1 to 7; Each of the displacement sensors is disposed at the free end of the corresponding first rod of the restraining member located at the top end; The heating device and the displacement sensor are both electrically connected to the controller, and the heating device is used to increase the temperature of the first rod.

9. A method for continuous pouring of concrete, characterized in that: Using the self-balancing correction system of claim 8, the construction method comprises: Determining the size of the restraining member according to the size of the casting member, wherein the size of the restraining member includes the pre-compression amount of the second rod; Assembling the self-balancing correction system and providing a supporting template around the restraining member; Concrete is poured in the supporting formwork.

10. The construction method according to claim 9, characterized in that: After pouring concrete in the support formwork, the construction method further includes: The first rod is removed, and the portion of the second rod extending beyond the cast part is removed.

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