Steel bar composite connecting structure with latch and construction method

Abstract

The latch type steel bar composite connecting structure and construction method relate to the field of building, and the latch type steel bar composite connecting structure comprises embedded steel bars one, embedded steel bars two, straight thread sleeves, grouting sleeves, movable connecting steel bars and electro-grouting materials. The straight thread sleeve far from the joint is a threaded section with internal threads on the inner side wall, and the straight thread sleeve is sleeved and fixedly connected with the embedded steel bars one. The grouting sleeve far from the joint is sleeved and fixedly connected with the embedded steel bars two through the prefabricated concrete grout. One section of the movable connecting steel bars is inserted into the straight thread sleeve through the external threads arranged on the outer side wall, and the other section is axially movably inserted into the grouting sleeve. The electro-grouting materials fill the gaps among the grouting sleeve, the movable connecting steel bars and the embedded steel bars two. The present application greatly reduces the component installation precision requirement and significantly reduces the field wet operation engineering quantity.

Description

Technical Field

[0001] This invention relates to the field of construction, and more particularly to connection structures for construction. Background Technology

[0002] Prefabricated concrete structures are the core development direction of building industrialization and green construction. The steel reinforcement connection between prefabricated components directly determines the overall load-bearing capacity, integrity, and durability of the structure.

[0003] Currently, the mainstream methods for connecting steel bars in precast concrete components in China are divided into three categories: grouting sleeve connection, mechanical connection of steel bars, and welding of steel bars.

[0004] All three connection methods have inherent technical flaws that cannot be overcome: Grouting sleeve connection has the advantages of good alignment tolerance and strong structural integrity. However, this process is a typical wet construction operation. The on-site grouting process is complicated, the workload is large, the curing period is long, and the grouting density and fullness are highly dependent on the on-site construction environment and the skill level of the workers. The construction quality is poorly controllable and the overall assembly construction efficiency is low.

[0005] Traditional mechanical connections for reinforcing bars are dry connections, which offer fast construction speed, high connection stiffness, and stable mechanical properties. However, they require extremely high precision in component alignment and rebar coaxiality. In situations involving precast component manufacturing errors, on-site hoisting deviations, or confined construction spaces, precise rebar alignment becomes difficult, drastically increasing construction complexity and even making assembly impossible, resulting in poor adaptability to various working conditions.

[0006] The welding process for reinforcing bars is greatly limited by weather, on-site electricity, fire safety, and high-altitude working conditions. The quality of manual welding is highly variable and prone to defects such as incomplete welds, slag inclusions, and cracks, resulting in poor structural reliability. Currently, the use of welding processes is strictly limited in the on-site construction of prefabricated buildings.

[0007] In existing technologies, single grouting, single machinery, and single welding methods cannot simultaneously meet the comprehensive construction requirements of high fault tolerance, low humidity operation, high efficiency, and high reliability. Therefore, the industry urgently needs a new structural form that combines the advantages of both types of connections and avoids various process defects in precast component steel reinforcement connection structures. Summary of the Invention

[0008] The purpose of this invention is to provide a pin-type steel bar composite connection structure to solve at least one of the above-mentioned technical problems.

[0009] The present invention also aims to provide a construction method for a pin-type steel bar composite connection structure.

[0010] The technical problem solved by this invention can be achieved by the following technical solutions: The pin-type steel bar composite connection structure includes a pre-embedded steel bar 1 embedded in a precast component 1 and a pre-embedded steel bar 2 embedded in a precast component 2. It also includes a straight threaded sleeve embedded in the precast component 1. The section of the straight threaded sleeve away from the joint is a threaded section with internal threads on its inner sidewall. The straight threaded sleeve is fitted and fixedly connected to the pre-embedded steel bar 1. It also includes a grouting sleeve embedded in the second precast component, wherein the end of the grouting sleeve away from the joint is fitted and anchored to the second precast steel bar through precast concrete grout; It also includes a movable connecting steel bar, one end of which is inserted into and connected to a straight threaded sleeve via an external thread provided on the outer side wall, and the other end is axially movable and inserted into the grouting sleeve; It also includes electro-inductive grouting material, which, by weight, comprises 100 parts cement-based substrate, 1-5 parts conductive phase material, 5-15 parts electrosensitive cementitious material, 0.5-2 parts water-reducing agent, 0.1-0.5 parts defoamer, and 20-30 parts water; the electrosensitive cementitious material is a composite microsphere, which has a microsphere shell made of chitosan-sodium alginate composite material, and the microsphere shell is filled with a curing agent, wherein the curing agent accounts for 30%-50% of the mass of the composite microsphere; the electro-inductive grouting material fills the gap between the grouting sleeve, the movable connecting steel bar, and the pre-embedded steel bar; A wire is embedded in the prefabricated component 1. One end of the wire is connected to the straight threaded sleeve, and the other end extends out of the prefabricated component 1. The straight threaded sleeve is a conductive sleeve. A second wire is embedded inside the precast component 2. One end of the second wire is connected to the grouting sleeve, and the other end extends out of the precast component 2.

[0011] This invention utilizes a novel composite system combining a conical adaptive fault-tolerant guiding structure, a pin-type sliding ribbed steel bar, a front-end dry mechanical locking mechanism, and a rear-end localized grouting anchorage. This system achieves several advantages: significantly reduced component installation accuracy requirements, a substantial reduction in on-site wet work, the dual benefits of high rigidity in mechanical connections and high integrity in grouting connections, and avoidance of on-site welding risks. Furthermore, by selecting the appropriate grout material, this invention enables rapid curing within one minute, thus maintaining construction efficiency. In addition, this invention replaces the pre-embedded steel bar power supply with a direct-threaded sleeve powering the movable connecting steel bar, ensuring that the area near the joint cures first and maintaining the electrode length.

[0012] Preferably, the section of the straight threaded sleeve near the joint is a tapered guide section, and the inner diameter of the tapered guide section increases as it approaches the joint. This tapered guide section guides the insertion of the movable reinforcing bar.

[0013] Preferably, the inner wall of the tapered guide section also has internal threads. This allows the internal threads to form a threaded connection with the electro-grouting material after the straight-threaded sleeve is injected, thereby improving anchoring performance.

[0014] Preferably, the movable connecting steel bar is a ribbed steel bar, wherein one section of the ribbed steel bar with external threads has no ribs, while the remaining portion has ribs. This invention selects a movable connecting steel bar with ribs to retain the original interlocking structure, thus satisfying the mechanical connection assembly requirements while maximizing the retention of anchorage performance.

[0015] Preferably, the external threads are distributed throughout the movable connecting steel bars. On the one hand, the external threads can be used instead of ribs to ensure anchorage performance; on the other hand, there is no need to determine the direction of the movable connecting steel bars during connection, thereby improving construction efficiency.

[0016] Preferably, the interior of the grouting sleeve is a non-smooth, through-hole cavity, and grouting holes are formed in the side walls of the grouting sleeve. A grouting channel is formed on the precast component two, and the grouting channel is connected to the grouting holes. This facilitates the injection of grouting material into the grouting sleeve and utilizes the cured grouting material to enhance the anchoring performance between the grouting sleeve and the precast component two.

[0017] Preferably, the inner diameter of the grouting sleeve is greater than the sum of the outer diameters of the second embedded reinforcing bar and the outer diameter of the movable connecting reinforcing bar, and the movable connecting reinforcing bar and the second embedded reinforcing bar are staggered within the grouting sleeve. This allows the movable connecting reinforcing bar and the second embedded reinforcing bar to be staggered, thereby ensuring the length of the movable connecting reinforcing bar and / or the second embedded reinforcing bar, which serve as the anode, within the grouting sleeve.

[0018] Preferably, the section of the grouting sleeve furthest from the joint is a tapered guide section, and the inner diameter of the tapered guide section decreases as it approaches the joint. This tapered guide section guides the insertion of the second embedded reinforcing bar and restricts the position of the grouting sleeve.

[0019] The construction method for a pin-type reinforced concrete composite connection includes the following steps: Step 1: Hoist the precast component into place, and embed a steel bar and a straight threaded sleeve inside the precast component. The straight threaded sleeve is fitted and fixedly connected to the embedded steel bar. Step 2: Hoist the precast component 2 into place. The precast component 2 has two embedded steel bars and a grouting sleeve. The grouting sleeve has a movable connecting steel bar that can move axially. Pull out the movable connecting steel bar and thread it into the straight thread sleeve. Step 3: Inject electro-hydraulic grout into the grouting sleeve, filling the gap between the grouting sleeve, the movable connecting steel bar, and the pre-embedded steel bar. The electro-hydraulic grout, by weight, comprises 100 parts cement-based substrate, 1-5 parts conductive phase material, 5-15 parts electrosensitive cementitious material, 0.5-2 parts water-reducing agent, 0.1-0.5 parts defoamer, and 20-30 parts water. The electrosensitive cementitious material is a composite microsphere, which has a chitosan-sodium alginate composite shell. The microsphere shell contains a curing agent, which accounts for 30%-50% of the composite microsphere's weight. Step 4: The straight threaded sleeve is a conductive sleeve. Using the straight threaded sleeve as the anode and the grouting sleeve as the cathode, apply a DC voltage of 10-30V until the electro-induced grouting material solidifies and hardens.

[0020] The position of the straight threaded sleeve is relatively fixed, which facilitates power supply.

[0021] Beneficial Effects: 1. Novel Structure: It is neither a purely mechanical connection nor a purely grouting connection, but a novel semi-dry composite system combining dry mechanical locking and localized grouting anchoring. No existing technology has a similar structure. 2. Unique Fault-Tolerant Principle: It adopts a tapered, gradually changing fault-tolerant guiding structure, solving the long-standing technical bias that mechanical connections require high-precision alignment, resulting in unexpected fault-tolerant construction effects. 3. Unique Reinforcement Construction: It uses a pin-type movable reinforcement with one end threaded and the entire length ribbed, retaining the original interlocking structure. This satisfies the assembly requirements of mechanical connections while maximizing anchoring performance. The design concept is reasonable and not a simple superposition of existing technologies. 4. Significant Process Advantages: It solves the shortcomings of the three mainstream connection processes in the industry, achieving a comprehensive technical effect of high fault tolerance, low-wet operation, high efficiency, and high reliability, demonstrating substantial improvement and significant progress. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a portion of the structure of the present invention; Figure 2 This is a partial structural diagram of another structure of the present invention; Figure 3 This is a partial structural diagram of another structure of the present invention; Figure 4 This is a real-life photo taken after 60 seconds of 20V DC power-on. Figure 5 These are comparison images of the microstructure obtained by scanning electron microscopy (SEM). Detailed Implementation

[0023] To make the technical means, creative features, objectives and effects of the invention easier to understand, the invention will be further explained below with reference to specific illustrations.

[0024] Reference Figure 1 , Figure 2 and Figure 3 A pin-type reinforced concrete composite connection structure includes precast component 1, precast component 2, embedded reinforcing bar 1, embedded reinforcing bar 2, straight threaded sleeve 5, grouting sleeve 7, movable connecting reinforcing bar 6, and electro-grouting material. Embedded reinforcing bar 3 and straight threaded sleeve 5 are embedded within precast component 1. Embedded reinforcing bar 2 and grouting sleeve 7 are embedded within precast component 2. A joint is formed at the junction of precast component 1 and precast component 2. Specific Implementation Example 1

[0026] The upper section of the straight threaded sleeve 5, furthest from the joint, is a threaded section with internal threads on its inner wall. The lower section, closer to the joint, is a tapered guide section, with its inner diameter increasing towards the joint. The tapered guide section guides the straight threaded sleeve 5, creating a natural, adaptive, gradual guiding and error-correcting channel. This channel is compatible with radial, axial, and lifting deviations of the component, adaptively offsetting lifting, fabrication, and rebar installation deviations, thus completely solving the alignment difficulties of traditional mechanical connections. The upper end of the straight threaded sleeve 5 is fixedly connected to the embedded rebar 3. This connection can be welded, threaded, or anchored via precast concrete. The lower end of the straight threaded sleeve 5 is flush with or slightly inward of the interface of the precast component 1.

[0027] The interior of the grouting sleeve 7 is a non-smooth, through-hole cavity. The lower end of the grouting sleeve 7 is fixedly connected to the second embedded steel bar 4. This fixed connection can be achieved through precast concrete anchoring, rather than a direct connection, thereby preventing electrical connection between the second embedded steel bar 4 and the grouting sleeve 7.

[0028] The upper end of the movable connecting steel bar 6 extends into the straight threaded sleeve 5 and is threadedly connected to the straight threaded sleeve 5. The lower end of the movable connecting steel bar 6 is inserted into the grouting sleeve 7 and can slide axially within the grouting sleeve 7. The movable connecting steel bar 6 is slidably positioned inside the grouting sleeve 7 without a fixed limiting structure, allowing for free extension and adjustment of the extension length to adapt to different joint widths in construction conditions. The structure is simple and has extremely high construction tolerance. Preferably, the movable connecting steel bar 6 is a ribbed steel bar used in building structures, with only one end processed to form an external thread section. The rest of the steel bar retains its original ribbed structure intact, without polishing, grinding, or altering the cross-sectional structure, maximizing the mechanical interlocking and anchoring performance with the grouting material. The anchoring strength is stable and reliable, the stress is uniform, there is no stress concentration, and the structural durability is excellent.

[0029] In the assembled state, the external threaded end of the movable connecting steel bar 6 passes through the tapered unthreaded guide section and screws into the internal threaded section of the straight threaded sleeve 5 to achieve a rigid mechanical connection. The ribbed section of the movable connecting steel bar 6 is located inside the grouting sleeve 7 and is anchored to the pre-embedded steel bar 4 by injecting grout to form an integral structure. This invention features a front-end tapered misalignment + rigid mechanical thread locking (dry connection) and a rear-end complete ribbed steel bar + partial sleeve grouting anchoring (wet anchoring), forming a brand-new semi-dry pin composite connection system in the industry. It does not belong to the traditional single mechanical connection, nor to the traditional pure grouting connection, and has new structural features that are significantly different from existing technologies.

[0030] The construction method is as follows: Step 1: Hoist the first precast component into position. A first precast steel bar and a straight threaded sleeve are pre-embedded inside the first precast component. The straight threaded sleeve is fitted and fixedly connected to the first precast steel bar. Step 2: Hoist the second precast component into position. A second precast steel bar and a grouting sleeve are pre-embedded inside the second precast component. A movable connecting steel bar that can move axially is inserted into the grouting sleeve. The movable connecting steel bar is pulled out and threadedly connected to the straight threaded sleeve. Step 3: Pour grout into the grouting sleeve. Step 4: Allow the grout to solidify and harden. Specific Implementation Example 2

[0032] The difference from Specific Embodiment 1 is that the internal thread covers the entire straight threaded sleeve 5. The section of the straight threaded sleeve 5 near the joint can still be tapered, meaning the inner diameter increases towards the joint. In this way, while retaining its original guiding and fault-tolerant functions, the straight threaded sleeve 5 can form a threaded anchoring structure with the grout entering the straight threaded sleeve 5, thereby improving the anchoring effect. The section of the straight threaded sleeve 5 near the joint has a sudden change in inner diameter; that is, from the side away from the joint to the side closer to the joint, the inner diameter first remains constant, then suddenly increases, then remains constant again, and then suddenly increases again. This abrupt change allows for the adaptation of movable connecting steel bars 6 of different thicknesses while retaining a certain degree of guidance. Specific Implementation Example 3

[0034] The difference from Specific Embodiment 1 is that the external threads are distributed throughout the movable connecting steel bar 6. On the one hand, the external threads can be used to replace the ribs to ensure anchorage performance; on the other hand, there is no need to determine the direction of the movable connecting steel bar 6 during connection, thereby improving construction efficiency. Specific Implementation Example 4

[0036] The difference from Specific Embodiment 1 is that the inner diameter of the grouting sleeve 7 is larger than the sum of the outer diameters of the pre-embedded reinforcing bar 4 and the movable connecting reinforcing bar 6, and the movable connecting reinforcing bar 6 and the pre-embedded reinforcing bar 4 are staggered within the grouting sleeve 7. This allows the movable connecting reinforcing bar 6 and the pre-embedded reinforcing bar 4 to be staggered, thereby ensuring the length of the movable connecting reinforcing bar 6 and / or the pre-embedded reinforcing bar 4, which can serve as the anode, within the grouting sleeve 7.

[0037] In this embodiment, the end of the grouting sleeve furthest from the joint is preferably provided with a guide plug 9. The guide plug 9 has a channel for guiding the second embedded reinforcing bar into place. The inner diameter of the channel decreases as it approaches the joint, thus facilitating the insertion of the second embedded reinforcing bar. Furthermore, the guiding direction of the channel is to guide the second embedded reinforcing bar close to the side wall of the grouting sleeve. This leaves space for the movable connecting reinforcing bar. The second embedded reinforcing bar can be directly guided to adhere tightly to the side wall of the grouting sleeve.

[0038] In this embodiment, the end of the movable connecting steel bar inserted into the grouting sleeve is provided with an end cap, and a guide cap 10 is fitted on the end cap. The outer diameter of the guide cap 10 gradually increases from both sides to the middle, thereby using the guide cap to make the movable connecting steel bar and the pre-embedded steel bar misaligned, while facilitating the pulling out of the movable connecting steel bar.

[0039] Both the guide plug and the guide cap are preferably made of non-conductive material. In this case, the guide plug and the guide cap can be used to isolate the movable reinforcing bar and the second embedded reinforcing bar. When the second embedded reinforcing bar is tightly attached to the side wall of the grouting sleeve, and there is a guide plug or guide cap between the movable reinforcing bar and the second embedded reinforcing bar, it is not necessary to set up a separate wire. The first embedded reinforcing bar can be used as the anode and the second embedded reinforcing bar as the cathode to apply current. In this way, the first embedded reinforcing bar will transfer electrons to the movable connecting reinforcing bar through the straight threaded sleeve, and the second embedded reinforcing bar will transfer electrons to the grouting sleeve.

[0040] In the above embodiments, the side wall of the grouting sleeve 7 has a grouting hole 8, and the precast component 2 has a grouting channel, which is connected to the grouting hole 8. This facilitates the injection of grouting material into the grouting sleeve 7 and enhances the anchoring performance between the grouting sleeve 7 and the precast component 2 after curing.

[0041] In the above embodiments, the outer wall of the grouting sleeve 7 may be provided with openings, thereby increasing the anchoring degree of the grouting sleeve 7 by utilizing the openings.

[0042] In the above embodiments, the internal thread portion of the straight threaded sleeve 5 is preferably no less than two-thirds of the length of the internal threaded sleeve. The length of the portion of the pre-embedded reinforcing bar 3 inserted into the straight threaded sleeve 5 is no less than one-third of the internal thread portion.

[0043] In the above embodiments, in Scheme 1, the length of the pre-embedded reinforcing bar 2 4 inserted into the grouting sleeve 7 is no more than one-third of the length of the grouting sleeve 7, and the length of the movable connecting reinforcing bar 6 is no less than two-thirds of the length of the grouting sleeve 7. In this scheme, the movable connecting reinforcing bar 6 or the straight threaded sleeve 5 is used as the anode. In Scheme 2, the length of the pre-embedded reinforcing bar 2 4 inserted into the grouting sleeve 7 is no less than two-thirds of the length of the grouting sleeve 7. In this scheme, the pre-embedded reinforcing bar 2 4 is used as the anode. In Scheme 3, the inner diameter of the grouting sleeve 7 is no less than 1.5 times the sum of the outer diameters of the pre-embedded reinforcing bar 2 4 and the movable connecting reinforcing bar 6, and the pre-embedded reinforcing bar 2 4 and the movable connecting reinforcing bar 6 are staggered and arranged in the grouting sleeve 7.

[0044] In the above embodiments, the preferred grouting material is an electro-hydraulic grouting material. The electro-hydraulic grouting material, by weight, comprises 100 parts cement-based substrate, 1-5 parts conductive phase material, 5-15 parts electrosensitive cementitious material, 0.5-2 parts water-reducing agent, 0.1-0.5 parts defoamer, and 20-30 parts water. The electrosensitive cementitious material is a composite microsphere, which has a chitosan-sodium alginate composite shell. The microsphere shell contains a curing agent, which accounts for 30%-50% of the composite microsphere's weight. The electro-hydraulic grouting material fills the gap between the grouting sleeve, the movable connecting steel bar 6, and the pre-embedded steel bar 4.

[0045] Principle: The electro-inducible grout of this invention employs a dual-path hardening process of "electric field-triggered release of curing agent + dual acceleration of cement hydration". When no electricity is applied, the curing agent is locked in the microsphere shell, resulting in slow hydration and extremely slow setting of the grout. Upon application of a 10-30V low-voltage DC current, the microsphere shell ruptures under the DC electric field, instantly releasing the internal curing agent throughout the entire structure, simultaneously catalyzing rapid cement hydration, and hardening occurs in 45-60 seconds. Each component in the formula plays a specific role, ensuring both low-voltage conduction of the electric field and the instantaneous release of the setting-promoting components upon energization. The principle is broken down by raw material: Electrosensitive cementitious material: When no electricity is applied, chitosan (cationic polysaccharide) and sodium alginate (anionic polysaccharide) undergo Ca... 2+ Cross-linking forms a dense and stable eggshell network, completely sealing the curing agent inside the microspheres and preventing it from contacting the cement matrix. The cement undergoes only weak natural hydration, and the slurry maintains a fluid state for an extended period. Upon energization, Ca... 2+ Cations migrate towards the cathode, and carboxyl anions migrate towards the anode, causing anisotropic swelling of the microsphere shell. Continuous low-voltage DC continuously widens the charge difference across the membrane, causing the microspheres to expand locally until they rupture. Upon rupture, the internal curing agent is instantly released into the slurry. This invention selects an electrosensitive gelling material. Many in the art believe that the microsphere shell will harden after energization, but in fact, the shell only softens, swells, and ruptures, not hardens. This is because: 1. "Hardening" requires more cross-linking points and tighter molecular chain bonding, but the DC electric field has the opposite effect. The electric field only removes the existing cross-linked cations Ca... 2+1. Stripping removes the crosslinking ions without creating new ones. 2. Polysaccharide macromolecules are pulled in opposite directions by the electric field, breaking the electrostatic bonds between chains and causing the polyelectrolyte composite membrane to dissociate. 3. The system contains only free water from the cement slurry, with no additional crosslinking agent, thus eliminating the conditions for electric field-induced secondary curing and hardening. This membrane only hardens when dried and dehydrated, or when a higher concentration of calcium salt / crosslinking agent is added; simply applying a low-voltage DC electric field will only cause decrosslinking, swelling, and cracking. Figure 5 As shown.

[0046] Conductive phase materials: In the grouting material, the cement-based matrix provides basic strength. Without conductive fillers, the cement-based matrix has extremely high resistance between the two poles, making it impossible for low-voltage current to penetrate the gaps inside the sleeve, and the electric field cannot act on all the microspheres. Carbon fibers have a large aspect ratio and overlap to form long-range conductive pathways; graphite powder fills the gaps between the carbon fibers, acting as a "conductive bridge." The combination of the two constructs a continuous three-dimensional conductive network.

[0047] Water-reducing agents are used to lower the viscosity of the grout, ensuring fluidity during the grouting stage. They also ensure uniform dispersion of carbon fibers, graphite powder, and microspheres, preventing the conductive filler from agglomerating and the microspheres from clumping together, thus guaranteeing a uniform electric field effect on each microsphere. Defoamers are used to eliminate air bubbles introduced during mixing and grouting, preventing the formation of insulating air bubbles inside the sleeve that could disrupt the conductive path, ensuring a continuous conductive network and eliminating blind spots in the low-voltage electric field. Water serves as both the cement hydration medium and an ion transport carrier, ensuring that ions can move freely under the electric field, allowing the microspheres to swell and rupture smoothly.

[0048] The cement-based substrate is at least one of silicate cement and sulfoaluminate cement, preferably grade 42.5 or 52.5 silicate cement. Silicate cement itself has rapid-hardening properties, and the rapid-setting effect is further amplified when combined with a curing agent. The conductive phase material is at least one of carbon fiber powder and graphite powder, with a particle size of 10-50 μm to ensure good conductivity and dispersibility. The curing agent accounts for 30%-50% of the mass of the microspheres in the electrosensitive cementitious material. The curing agent can be epoxy resin curing agent, polyurethane curing agent, etc., preferably an amine curing agent. The preparation method of chitosan-sodium alginate composite microspheres is as follows: chitosan solution (mass concentration 2%-5%) and sodium alginate solution (mass concentration 2%-5%) are mixed at a volume ratio of 1:1-3, curing agent powder is added, and after stirring evenly, it is dripped into a calcium chloride solution with a mass concentration of 1%-3% using a syringe, solidified and shaped, filtered and dried to obtain microspheres.

[0049] When using electro-grouting material, the movable connecting steel bar 6 and / or the pre-embedded steel bar 4 are used as the anode, and the grouting sleeve is used as the cathode. A DC voltage of 10-30V is applied until the electro-grouting material solidifies and hardens. Preferably, the straight threaded sleeve 5 is a conductive sleeve, through which current is applied to the movable connecting steel bar 6. The position of the straight threaded sleeve 5 is relatively fixed, facilitating power supply. Moreover, since the straight threaded sleeve 5 is connected to the pre-embedded steel bar 3, power can also be supplied directly from the pre-embedded steel bar 3. During prefabrication, a conductor 1 can be embedded in the prefabricated component 1, with one end connected to the straight threaded sleeve 5 and the other end extending outside the prefabricated component 1. A conductor 2 can be embedded in the prefabricated component 2, with one end connected to the grouting sleeve 7 and the other end extending outside the prefabricated component 2. After power supply is completed, the portion of the conductor protruding outside the prefabricated component 1 and prefabricated component 2 is cut off. Preferably, the conductor 2 extends from the grouting channel, thus eliminating the need for a separate channel. This invention optimizes the grouting material. Through an electro-coagulation mechanism, the grouting material of this invention can achieve rapid setting and hardening within one minute, effectively solving the problem of long setting time of traditional grouting materials. This significantly improves the construction efficiency of prefabricated buildings, reduces labor costs, and has good application prospects. This invention preferably uses direct current (DC). DC can establish a stable unidirectional electric field gradient, and low voltage is sufficient to accumulate enough stress to break the microsphere shell. The voltage used in this invention is low-voltage DC because: 1. Triggering microsphere rupture does not require breakdown or heating, only a stable unidirectional charge gradient; the polysaccharide cross-linked membrane is mechanically weak and can be broken by a small electric field stress, without the need for high voltage; 2. The conductive network of the system is only used to transmit the electric field, and there is no high-power electrothermal effect; the electrodes are only steel bars / sleeve metal parts with a large conductive cross-section and low loop resistance, resulting in a weak current during energization; and hardening can be completed in only 45–60 seconds, with extremely low total power consumption. 3. The alternating current electric field periodically reverses direction, and ions migrate back and forth, making it impossible to form a continuous unidirectional swelling stress on the microsphere membrane wall. As a result, the microsphere will not rupture and cannot release the curing agent. Only direct current can establish a stable unidirectional electric field gradient, enabling controllable triggering of rapid coagulation.

[0050] Example 1 of the electro-inducible grouting material comprises, by weight, 100 parts of 52.5 grade silicate cement, 3 parts of carbon fiber powder (particle size 20μm), 10 parts of electrosensitive cementitious material, 1 part of polycarboxylate superplasticizer, 0.3 parts of silicone polyether defoamer, and 25 parts of water. The electrosensitive cementitious material is chitosan-sodium alginate composite microspheres coated with ethylenediamine curing agent, with the curing agent accounting for 40% of the microsphere mass. The composite microspheres are prepared by mixing 3% chitosan solution and 3% sodium alginate solution at a volume ratio of 1:2, adding ethylenediamine powder, stirring evenly, and then dripping into a 2% calcium chloride solution to solidify and form the microspheres. The mixture is then filtered and dried to obtain the final product. Preparation method: (1) Weigh each raw material according to the above mass parts; (2) Put silicate cement and carbon fiber powder into a mixing pot and stir for 2 minutes to mix evenly; (3) Add electrosensitive cementitious material, polycarboxylate superplasticizer and silicone polyether defoamer, and continue stirring for 2 minutes; (4) Finally add water and stir for 4 minutes to obtain grouting material.

[0051] Construction methods, such as Figure 4 As shown: Step 1, hoist the precast component 1 into position, pre-embed a reinforcing bar 1 and a straight threaded sleeve inside the precast component 1, and fit and fix the pre-embedded reinforcing bar 1 inside the straight threaded sleeve; Step 2, hoist the precast component 2 into position, pre-embed a reinforcing bar 2 and a grouting sleeve inside the precast component 2, insert a movable connecting reinforcing bar that can move axially inside the grouting sleeve, pull out the movable connecting reinforcing bar and thread it into the straight threaded sleeve; Step 3, inject grout into the grouting sleeve; Step 4, inject the prepared electro-grout into the gap between the sleeve, the movable connecting reinforcing bar 6, and the pre-embedded reinforcing bar 2 4; Step 5, with the pre-embedded reinforcing bar 2 4 as the anode and the grouting sleeve as the cathode, apply a 20V DC voltage, and after 45 seconds of energizing, the grout completely solidifies and hardens, at which point its compressive strength is measured to reach 30MPa. Upon release of the curing agent, two hardening reactions are triggered simultaneously, achieving a strength of approximately 30 MPa within one minute: 1) Cement hydration catalysis: Amines (ethylenediamine, triethylenetetramine) react with Al in the cement. 3+ Ca 2+ 1) Formation of complexes, accelerating the dissolution of tricalcium silicate and tricalcium aluminate, rapidly generating ettringite and CSH gel, forming a dense hardened skeleton in a short time; 2) Organic cross-linking-assisted curing: A small amount of curing agent cross-links with polysaccharide microsphere fragments and trace organic components in the system, filling the cement hydration pores and further shortening the initial setting and final setting interval.

[0052] Example 2 of electro-curing grout: A high-strength sleeve grout that rapidly sets electro-cures, comprising, by weight, 100 parts of 42.5 grade sulfoaluminate cement, 4 parts of graphite powder (30 μm particle size), 12 parts of electrosensitive cementitious material, 1.5 parts of naphthalene-based water-reducing agent, 0.4 parts of organosilicon defoamer, and 28 parts of water. The electrosensitive cementitious material is chitosan-sodium alginate composite microspheres coated with triethylenetetramine curing agent, with the curing agent accounting for 45% of the microsphere mass. The composite microspheres are prepared by mixing 4% chitosan solution and 2% sodium alginate solution at a volume ratio of 1:3, adding triethylenetetramine powder, stirring evenly, and then dripping it into a 1.5% calcium chloride solution to solidify and form the grout. The mixture is then filtered and dried to obtain the final product. Preparation method: (1) Weigh each raw material according to the above mass parts; (2) Put sulfoaluminate cement and graphite powder into a mixing pot and stir for 2 minutes to mix evenly; (3) Add electrosensitive cementitious material, naphthalene water-reducing agent and organosilicon defoamer, and continue stirring for 2 minutes; (4) Finally add water and stir for 4 minutes to obtain grouting material.

[0053] Construction Method: Step 1: Hoist the precast component 1 into position. Embed a reinforcing bar 1 and a straight threaded sleeve within the precast component 1. The straight threaded sleeve is fitted and fixedly connected to the embedded reinforcing bar 1. Step 2: Hoist the precast component 2 into position. Embed a reinforcing bar 2 and a grouting sleeve within the precast component 2. A movable connecting reinforcing bar that can move axially is inserted into the grouting sleeve. Pull out the movable connecting reinforcing bar and thread it into the straight threaded sleeve. Step 3: Inject grout into the grouting sleeve. Step 4: Inject the prepared electro-grout into the gap between the sleeve, the movable connecting reinforcing bar 6, and the second embedded reinforcing bar 4. Step 5: Using the straight threaded sleeve 5 as the anode and the grouting sleeve as the cathode, apply a 25V DC voltage. After 50 seconds of energizing, the grout hardens, achieving a compressive strength of 28MPa.

[0054] In the above embodiments, a gap may be left between precast component one and precast component two, the gap being determined according to specific construction requirements. This gap is sealed later by filling with grout. In cases of large gaps, it is permissible not to provide a separate grouting channel and directly fill the grouting sleeve with electro-grout through this gap. Alternatively, it is also permissible to directly use the movable connecting steel bar as the anode. Electro-grout can also be filled between the straight threaded sleeve and the movable connecting steel bar.

[0055] Note: The directions "up" and "down" in the instruction manual are based on the attached document. Figure 1 The orientation is standard. In actual use, the positions of precast component one and precast component two can be interchanged, or they can be set left and right. In this case, the orientation of the straight threaded sleeve, movable connecting steel bar, and grouting sleeve can be changed accordingly.

[0056] The foregoing has shown and described the basic principles, main features, and advantages of the invention. Those skilled in the art should understand that the invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made without departing from the spirit and scope of the invention, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection of the invention is defined by the appended claims and their equivalents.

Claims

1. A pin-type composite rebar connection structure, comprising a first pre-embedded rebar embedded in a first precast component and a second pre-embedded rebar embedded in a second precast component, characterized in that, It also includes a straight threaded sleeve embedded in the precast component 1. The section of the straight threaded sleeve away from the joint is a threaded section with internal threads on the inner side wall. The straight threaded sleeve is fitted and fixedly connected to the pre-embedded steel bar 1. It also includes a grouting sleeve embedded in the second precast component. The end of the grouting sleeve away from the joint is fitted and anchored to the second precast steel bar through precast concrete grout. It also includes a movable connecting steel bar, one end of which is inserted into and connected to a straight threaded sleeve via an external thread on the outer side wall, and the other end is axially movable and inserted into the grouting sleeve. It also includes electro-grouting material, which, by weight, comprises 100 parts cement-based substrate, 1-5 parts conductive phase material, 5-15 parts electrosensitive cementitious material, 0.5-2 parts water-reducing agent, 0.1-0.5 parts defoamer, and 20-30 parts water; the electrosensitive cementitious material is a composite microsphere, which has a microsphere shell made of chitosan-sodium alginate composite material, and the microsphere shell is filled with a curing agent, wherein the curing agent accounts for 30%-50% of the mass of the composite microsphere; the electro-grouting material fills the gap between the grouting sleeve, the movable connecting steel bar, and the pre-embedded steel bar; A wire is embedded in the prefabricated component 1. One end of the wire is connected to the straight threaded sleeve, and the other end extends out of the prefabricated component 1. The straight threaded sleeve is a conductive sleeve. A second wire is embedded inside the precast component 2. One end of the second wire is connected to the grouting sleeve, and the other end extends out of the precast component 2.

2. The pin-type steel bar composite connection structure according to claim 1, characterized in that, The section of the straight threaded sleeve near the joint is a tapered guide section, and the inner diameter of the tapered guide section increases as it gets closer to the joint.

3. The pin-type steel bar composite connection structure according to claim 2, characterized in that, The inner wall of the tapered guide section also has internal threads.

4. The pin-type steel bar composite connection structure according to claim 1, characterized in that, The movable connecting steel bar is a ribbed steel bar, and the ribbed steel bar has no ribs on one section with external threads, while the remaining part has ribs.

5. The pin-type steel bar composite connection structure according to claim 1, characterized in that, The external threads are distributed throughout the movable connecting steel bars.

6. The pin-type steel bar composite connection structure according to claim 1, characterized in that, The interior of the grouting sleeve is a non-smooth, through-hole cavity. Grouting holes are opened on the side wall of the grouting sleeve. A grouting channel is opened on the precast component 2, and the grouting channel is connected to the grouting hole.

7. The pin-type steel bar composite connection structure according to claim 1, characterized in that, The inner diameter of the grouting sleeve is greater than the sum of the outer diameter of the second embedded steel bar and the outer diameter of the movable connecting steel bar. The movable connecting steel bar and the second embedded steel bar are staggered inside the grouting sleeve.

8. The pin-type steel bar composite connection structure according to claim 1, characterized in that, The section of the grouting sleeve furthest from the joint is a tapered guide section, and the inner diameter of the tapered guide section is smaller as it gets closer to the joint.

9. A construction method for a pin-type reinforced concrete composite connection structure, characterized in that, Includes the following steps: Step 1: Hoist the precast component into place, and embed a steel bar and a straight threaded sleeve inside the precast component. The straight threaded sleeve is fitted and fixedly connected to the embedded steel bar. Step 2: Hoist the precast component 2 into place. The precast component 2 has two embedded steel bars and a grouting sleeve. The grouting sleeve has a movable connecting steel bar that can move axially. Pull out the movable connecting steel bar and thread it into the straight thread sleeve. Step 3: Inject electro-hydraulic grout into the grouting sleeve, filling the gap between the grouting sleeve, the movable connecting steel bar, and the pre-embedded steel bar. The electro-hydraulic grout, by weight, comprises 100 parts cement-based substrate, 1-5 parts conductive phase material, 5-15 parts electrosensitive cementitious material, 0.5-2 parts water-reducing agent, 0.1-0.5 parts defoamer, and 20-30 parts water. The electrosensitive cementitious material is a composite microsphere, which has a chitosan-sodium alginate composite shell. The microsphere shell contains a curing agent, which accounts for 30%-50% of the composite microsphere's weight. Step 4: The straight threaded sleeve is a conductive sleeve. Using the straight threaded sleeve as the anode and the grouting sleeve as the cathode, apply a DC voltage of 10-30V until the electro-induced grouting material solidifies and hardens.

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