Prefabricated concrete component manufacturing process

Abstract

The invention provides a precast concrete component manufacturing process which comprises the following steps: S1, pretreating a mold and a core area, cleaning impurities in a mold cavity, coating the mold cavity with a release agent, dividing the mold cavity into the core area and a common area, and performing surface treatment and positioning protection on reinforcing steel bars or embedded parts in the core area, through cooperation of regional treatment and a composite process, firstly, a core region is pretreated, high-fluidity fine aggregate concrete is poured, then high-frequency vibration and controllable negative pressure operation are synchronously used, program interlocking control is matched, the problems that filling in a complex region is not compact, and bubbles are difficult to discharge are accurately solved, and the component defects of a traditional process are avoided.

Description

Technical Field

[0001] This invention relates to the field of precast concrete component manufacturing technology, specifically a precast concrete component manufacturing process. Background Technology

[0002] Precast concrete components are currently a core part of industrialized building construction, widely used in residential and municipal engineering projects. Their production efficiency and quality directly determine project progress and structural safety. The current mainstream industry method is "integral casting + single vibration": ordinary concrete is first injected into the mold cavity in one go, and then vibrated at a single frequency using a vibrator fixed to the outside of the mold. However, for complex components with openings (where reinforcement bars are densely arranged around the openings, often less than 50mm apart) and areas with concentrated embedded parts (such as wall panel lifting rings and densely packed connecting bolts), the fluidity of ordinary concrete is difficult to adapt to the narrow space of the core area. This easily leads to problems such as aggregate getting stuck in the gaps between reinforcement bars and incomplete concrete filling, resulting in honeycomb and voids inside the component. Furthermore, single vibration can only remove surface air bubbles; deep air bubbles can cause surface pitting and porosity, requiring manual removal of defects and recasting for repair. This increases the repair cost per component by 15%-20% and extends the production cycle by 3-5 days, making it difficult to meet the dual demands of efficiency and quality for industrialized mass production.

[0003] While the existing patent CN112518783A (a concrete precast component casting process) attempts to optimize the process through "primary and secondary zone zoning casting," it has significant limitations: it only divides the mold into primary and secondary zones according to the component size, without designing a suitable solution for the special structure of the core area (door and window openings, areas with dense reinforcement). It does not perform rust removal on the reinforcement in the core area, nor does it provide positioning protection for embedded parts, nor does it use high-flowability fine aggregate concrete, resulting in the problem of insufficient compaction in the core area. At the same time, this patent relies solely on high-frequency vibration compaction without introducing controllable negative pressure for synergistic venting, resulting in a deep air bubble removal rate of less than 60%, and the surface defect rate of the component remains above 12%. Furthermore, its process does not address emergency treatment for casting interval delays (such as the lack of roughening and transition layer measures after initial setting), nor does it have a concrete waste recycling mechanism. During production, construction joints and waste waste can easily further reduce component quality and resource utilization, failing to fundamentally solve the core pain points of complex precast components. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a manufacturing process for precast concrete components, which solves the problems of insufficient filling of the core area and the expulsion of deep air bubbles during the manufacturing of existing precast concrete components.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention provides the following technical solution: a process for manufacturing precast concrete components, comprising the following steps:

[0008] S1. Mold and core area pretreatment: clean impurities in the mold cavity and apply release agent; divide the mold cavity into core area and ordinary area; perform surface treatment and positioning protection on the steel bars or embedded parts in the core area.

[0009] S2. Core area pouring and preliminary vibration: Pour fine aggregate concrete with higher fluidity than ordinary concrete into the core area, and then use a high-frequency vibrator to perform preliminary vibration on the core area after pouring.

[0010] S3. For ordinary area pouring, ordinary concrete is poured into the ordinary area before the fine stone concrete in the core area sets to complete the overall pouring; if the pouring interval exceeds the initial setting time, the poured area is roughened and a transition layer material is laid before pouring.

[0011] S4. Composite vibration and directional venting: After the overall casting, high-frequency mold vibration and controllable negative pressure on the surface of the component are executed simultaneously. The parameters and timing of the two are interlocked and controlled by the program controller to achieve compaction and venting.

[0012] S5. Curing and demolding: After curing the components until they reach the required strength, demold them using an adapter.

[0013] S6. Production support processing, collection and recycling of scattered concrete waste, noise reduction and protection in high-frequency vibration areas, and addition of safety components to negative pressure equipment.

[0014] Preferably, in S1, high-pressure airflow is used for mold cleaning, the release agent is water-based and evenly applied; rust is removed from the reinforcing bars in the core area, and elastic gaskets are placed on the embedded parts.

[0015] Preferably, the fine aggregate concrete and ordinary concrete in S2 and S3 are poured using automated pouring equipment. The automated pouring equipment receives instructions from the program controller and pours in different areas according to the speed adapted to the concrete's fluidity. The transition layer material is cement mortar of the same strength.

[0016] Preferably, the initial vibration and high-frequency mold vibration in S2 and S4 are achieved by multiple high-frequency vibrators at specific locations on the mold; the program controller controls the start and stop of the vibrators, frequency and duration in a zoned and timed manner, and the vibration parameters of the core area and the ordinary area are set differently.

[0017] Preferably, the controllable negative pressure in S4 is achieved through a microporous vacuum network on the decorative surface of the corresponding component or the area where air bubbles tend to accumulate within the mold. The negative pressure value is dynamically adjusted according to the pouring progress and the state of the concrete. If the negative pressure exceeds a reasonable range, the program controller first adjusts the vibration parameters, and then restores the original parameters after the negative pressure returns to normal.

[0018] Preferably, the curing in S5 is constant temperature and humidity curing or steam curing; before demolding, the strength of the component is tested to ensure it meets the standard and there is no mold adhesion, and the demolding device applies force at a uniform speed to avoid damage to the component.

[0019] Preferably, in step S6, the concrete waste is crushed and screened and then mixed into ordinary concrete in an appropriate proportion; and the soundproof enclosure for noise reduction and protection, and the safety component of the negative pressure equipment is a pressure safety valve.

[0020] (III) Beneficial Effects

[0021] This invention provides a manufacturing process for precast concrete components. It has the following beneficial effects:

[0022] 1. This invention uses a combination of regional processing and composite processes: first, the core area is pre-treated and high-flowability fine stone concrete is poured, and then high-frequency vibration and controllable negative pressure are used simultaneously, along with program interlocking control, to accurately solve the problems of incomplete filling and difficulty in removing air bubbles in complex areas, thus avoiding the component defects of traditional processes.

[0023] 2. The present invention significantly improves the one-time molding qualification rate of components, reduces manual intervention through automated casting, and shortens the production cycle; at the same time, concrete waste can be recycled, noise reduction protection is provided in the high-frequency vibration zone, and safety components are added to the negative pressure equipment, taking into account production efficiency, environmental protection and operational safety, and adapting to the needs of industrial mass production. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example:

[0026] This invention provides a process for manufacturing precast concrete components, including the following steps:

[0027] S1. Mold and core area pretreatment: Clean the mold cavity of impurities and apply a release agent. Divide the mold cavity into a core area and a normal area. Perform surface treatment and positioning protection on the reinforcing bars or embedded parts in the core area. In S1, high-pressure airflow is used to clean the mold. The release agent is water-based and applied evenly. Rust is removed from the reinforcing bars in the core area, and elastic gaskets are placed on the embedded parts.

[0028] (1) When pre-processing the mold and core area, first perform the mold cleaning operation: use high-pressure airflow to blow along the inner wall of the mold cavity at a uniform speed, focusing on cleaning areas where impurities easily accumulate, such as the corners of the cavity and the installation slots of embedded parts, to ensure that there is no dust or debris residue; if there is concrete block residue, first use a plastic scraper to gently scrape it off before blowing, to avoid damaging the precision of the inner wall of the mold.

[0029] (2) After the mold is cleaned, apply a release agent: Select a water-based release agent and spray it evenly along the inner wall of the cavity through a sprayer. Keep the distance between the spray nozzle and the inner wall 30-50cm to ensure that the release agent forms a continuous, uniform film without any gaps or drips. After coating, visually check to confirm the integrity of the coverage. Any gaps need to be re-sprayed.

[0030] (3) Then, the core area is divided and treated: According to the component design drawings, the area around the door and window openings, the area with dense steel bars, or the area with concentrated embedded parts is designated as the core area; the steel bars in the core area are wiped along the length direction with a wire brush until there are no visible rust marks or oxide scale; for the embedded parts, elastic shims are placed at the contact points between them and the mold cavity - the shim material is rubber, and the thickness is selected according to the specifications (thickness, weight) of the embedded parts (usually 2-3mm) to ensure that the bottom of the embedded parts forms a flexible buffer with the inner wall of the mold to avoid displacement during subsequent vibration; after the shims are laid, the embedded parts are gently pushed to confirm that there is no looseness, and the positioning protection is completed.

[0031] S2, Core Area Pouring and Preliminary Vibration: Fine aggregate concrete with higher fluidity than ordinary concrete is poured into the core area. After pouring, a high-frequency vibrator is used to preliminarily vibrate the core area. In S2 and S3, fine aggregate concrete and ordinary concrete are poured using automated pouring equipment. The automated pouring equipment receives instructions from the program controller and pours in different areas according to the speed of concrete fluidity. The transition layer material is cement mortar of the same strength.

[0032] (1) Before pouring the core area, calibrate the automated pouring equipment: The equipment includes a storage tank, a movable pouring arm and a flow control module. After receiving the instructions from the program controller, the fine stone concrete is first sent into the storage tank. The fluidity is monitored by the built-in slump monitor (to ensure that it is higher than that of the subsequent ordinary concrete). If it does not meet the standard, a small amount of mixing water (≤1% of the total mass of concrete) can be added to adjust it.

[0033] (2) During pouring, the program controller controls the pouring arm to move above the core area and pours in sections according to the speed of the fine stone concrete flowability: from the edge of the core area to the center to avoid local accumulation; when pouring to 1 / 2 of the design height, pause for 10-15 seconds and wait for the concrete to fill the gaps naturally before continuing until the core area is filled.

[0034] (3) After pouring, start the initial vibration: the high-frequency vibrator is fixed in advance on the outer wall of the core area of ​​the mold (at least 2 in each core area, symmetrically distributed, and the bolts are tightened to ensure vibration transmission); the program controller controls the vibrator to vibrate at a differentiated frequency (adapted to the core area structure) for 30-60s, and stops when a small amount of floating slurry appears on the surface and no air bubbles overflow; if aggregate accumulation is found, a small amount of fine stone concrete can be added and then vibrated for a short time (5-10s).

[0035] S3. For ordinary area pouring, ordinary concrete is poured into the ordinary area before the fine stone concrete in the core area sets to complete the overall pouring; if the pouring interval exceeds the initial setting time, the poured area is roughened and a transition layer material is laid before pouring.

[0036] (1) After the initial vibration of the core area is completed, prepare for the pouring of the ordinary area immediately: record the pouring time of the core area by using a time relay, and at the same time use a penetration resistance meter to detect the initial setting state of the concrete in the core area to ensure that the pouring of the ordinary area starts before the initial setting.

[0037] (2) The pouring of ordinary concrete is still performed by automated pouring equipment: the program controller switches parameters and pours at a speed that is adapted to the fluidity of ordinary concrete (higher than the pouring speed of the core area). The pouring arm moves from the end away from the core area to the core area to avoid impacting the concrete in the core area.

[0038] (3) If the pouring interval exceeds the initial setting time, stop pouring immediately: use an electric chisel to roughen the surface of the core area (3-5mm deep), then lay a transition layer material - cement mortar of the same strength grade as the concrete, 5-10mm thick, smooth it, and wait for the mortar to initially set (10-15min) before restarting pouring to ensure that the core area and the ordinary area are tightly bonded without construction joints.

[0039] S4, composite vibration and directional venting: After overall casting, high-frequency mold vibration and controllable negative pressure on the component surface are executed simultaneously. The parameters and timing of both are interlocked and controlled by a program controller to achieve compaction and venting. In S2 and S4, preliminary vibration and high-frequency mold vibration are achieved through multiple high-frequency vibrators at specific locations on the mold. The program controller controls the start and stop, frequency and duration of the vibrators in zones and timing, and sets vibration parameters differently for the core area and ordinary area. The controllable negative pressure in S4 is achieved through a microporous vacuum network in the mold corresponding to the decorative surface of the component or the area where air bubbles tend to accumulate. The negative pressure value is dynamically adjusted according to the casting progress and the state of the concrete. If the negative pressure exceeds the reasonable range, the program controller first adjusts the vibration parameters, and restores the original parameters after the negative pressure returns to normal.

[0040] (1) After the overall casting is completed, high-frequency mold vibration and controllable negative pressure are started simultaneously:

[0041] High-frequency mold vibration: High-frequency vibrators are arranged on the outer wall of the ordinary zone (1-2 in each ordinary zone). The program controller controls the vibrator in the core zone to vibrate at a frequency of 250-300Hz and the vibrator in the ordinary zone to vibrate at a frequency of 200-250Hz for 120-180s. The current signal is collected in real time during vibration. If the current is abnormal, the backup vibrator is switched immediately to avoid vibration interruption.

[0042] Controllable negative pressure application: In the decorative surface of the components inside the mold and in areas where air bubbles tend to accumulate, a PVC vacuum pipe network with micropores (pipe diameter 10-15mm, micropore diameter 1-2mm) is pre-laid and connected to a vacuum negative pressure device; the negative pressure value is dynamically adjusted according to the pouring progress and the state of the concrete (normal range -0.02MPa to -0.05MPa).

[0043] Interlock control: If the negative pressure exceeds the reasonable range, the program controller will first reduce the vibrator frequency to 150-200Hz, adjust the vacuum valve opening to bring the negative pressure back to normal, and then restore the original vibration parameters to ensure that vibration and exhaust are coordinated.

[0044] S5. Curing and Demolding: After curing the components until they reach the required strength, use an adapter to demold them. In S5, curing is carried out using constant temperature and humidity curing or steam curing. Before demolding, check that the components have the required strength and that there is no mold adhesion. The demolding device applies force at a uniform speed to avoid damage to the components.

[0045] (1) After vibration is completed, transfer the components to the curing area:

[0046] If standard constant temperature and humidity curing is used, the ambient temperature is controlled at 20±2℃, the relative humidity is ≥90%, and the curing time is ≥7 days.

[0047] If steam curing is used, the temperature should be increased to 60±5℃ at a rate of 5-10℃ / h and cured for 48 hours. After curing, the compressive strength of the component should be tested with a rebound hammer. Demolding can only be prepared after the strength meets the standard (≥75% of the design value).

[0048] (2) The demolding operation adopts a hydraulic jacking device: the jacking head of the device is wrapped with a rubber pad, and the program controller controls the application of jacking force (5-10kN, adapted to the weight of the component) at a speed of 5-10mm / s; if local adhesion is found during jacking, pause and insert a plastic wedge to pry it off until the mold is completely removed; after demolding, visually inspect the surface of the component to confirm that there are no defects such as missing edges, corners, or pitting.

[0049] S6. Production supporting treatment, collection and recycling of scattered concrete waste during pouring, noise reduction and protection in high-frequency vibration areas, and safety components for negative pressure equipment. In S6, the concrete waste is crushed and screened and then mixed into ordinary concrete in an appropriate proportion. Noise reduction and protection are achieved with soundproof barriers, and the safety components of the negative pressure equipment are pressure safety valves.

[0050] (1) Simultaneous recycling of concrete waste during the pouring process: Set up a receiving trough (slightly larger than the mold and 100-150mm deep) under the mold to collect scattered waste; after pouring, crush the waste and pass it through a 5mm sieve to remove large-diameter aggregates, and add it to the next batch of mix at a ratio of ≤10% of the total mass of ordinary concrete. Before adding, the moisture content of the waste needs to be tested and the amount of mixing water adjusted to ensure the stability of the mix ratio.

[0051] (2) Implement safety and noise reduction protection at the same time: Set up a 1.2-1.5m high soundproof enclosure (double-layer color steel plate sandwiched with 50-100mm thick sound insulation cotton, bolted) around the high-frequency vibrator to block vibration noise; install a pressure safety valve (opening pressure -0.01MPa) on the vacuum pump outlet pipe of the vacuum negative pressure device to automatically release pressure when the negative pressure rises abnormally; operators must wear anti-vibration gloves in the vibration operation area to reduce the impact of vibration.

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A manufacturing process for precast concrete components, characterized in that, Includes the following steps: S1. Mold and core area pretreatment: clean impurities in the mold cavity and apply release agent; divide the mold cavity into core area and ordinary area; perform surface treatment and positioning protection on the steel bars or embedded parts in the core area. S2. Core area pouring and preliminary vibration: Pour fine stone concrete with higher fluidity than ordinary concrete into the core area, and then use a high-frequency vibrator to perform preliminary vibration on the core area after pouring. S3. For ordinary area pouring, ordinary concrete is poured into the ordinary area before the fine stone concrete in the core area sets to complete the overall pouring; if the pouring interval exceeds the initial setting time, the poured area is roughened and a transition layer material is laid before pouring. S4. Composite vibration and directional venting: After the overall casting, high-frequency mold vibration and controllable negative pressure on the surface of the component are executed simultaneously. The parameters and timing of the two are interlocked and controlled by the program controller to achieve compaction and venting. S5. Curing and demolding: After curing the components until they reach the required strength, demold them using an adapter. S6. Production support processing, collection and recycling of scattered concrete waste, noise reduction and protection in high-frequency vibration areas, and addition of safety components to negative pressure equipment.

2. The manufacturing process for precast concrete components according to claim 1, characterized in that: In S1, high-pressure airflow is used for mold cleaning, and the release agent is water-based and evenly applied; rust is removed from the reinforcing bars in the core area, and elastic gaskets are placed on the embedded parts.

3. The manufacturing process for precast concrete components according to claim 1, characterized in that: In S2 and S3, fine aggregate concrete and ordinary concrete are poured using automated pouring equipment. The automated pouring equipment receives instructions from the program controller and pours in different areas according to the speed adapted to the fluidity of the concrete. The transition layer material is cement mortar of the same strength.

4. The manufacturing process for a precast concrete component according to claim 1, characterized in that: In S2 and S4, the initial vibration and high-frequency mold vibration are achieved by multiple high-frequency vibrators at specific locations on the mold; the program controller controls the start and stop of the vibrators, the frequency and duration by partitioning and timing, and the vibration parameters of the core area and the ordinary area are set differently.

5. The manufacturing process for a precast concrete component according to claim 1, characterized in that: The controllable negative pressure in S4 is achieved through a microporous vacuum network on the decorative surface of the corresponding component or the area where air bubbles tend to accumulate within the mold. The negative pressure value is dynamically adjusted according to the pouring progress and the state of the concrete. If the negative pressure exceeds a reasonable range, the program controller first adjusts the vibration parameters, and then restores the original parameters after the negative pressure returns to normal.

6. The manufacturing process for a precast concrete component according to claim 1, characterized in that: In S5, the curing process adopts constant temperature and humidity curing or steam curing; before demolding, the strength of the component is tested to ensure that it meets the standard and there is no mold adhesion, and the demolding device applies force at a uniform speed to avoid damage to the component.

7. The manufacturing process for a precast concrete component according to claim 1, characterized in that: In S6, the concrete waste is crushed and screened and then mixed into ordinary concrete in an appropriate proportion; and the noise reduction and protection are provided by soundproof enclosures, and the safety component of the negative pressure equipment is a pressure safety valve.