Preparation process of self-adaptive vibration-vacuum composite mould pressing prefabricated wallboard

Abstract

According to the preparation process of the self-adaptive vibration-vacuum composite mould pressing prefabricated wallboard, through dynamic adjustment of the self-adaptive vibration frequency (50-80 Hz) and the vacuum degree (0.02-0.04 MPa) controlled by a PLC and in combination with silane-nano silicon dioxide composite modified rubber particles, high-precision forming (the size deviation is + / -0.8 mm) and excellent mechanical performance (the compressive strength is 9.2 MPa) are achieved. The process is suitable for producing large prefabricated wallboards (such as 1000 * 500 * 100 mm), and the crack resistance and durability are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building material preparation, in particular to a vibration-vacuum composite mold pressing preparation process of foam concrete prefabricated wallboard based on high polymer fiber reinforcement, doping 10 mesh and 40 mesh rubber particles, and using sodium dodecyl sulfate foaming agent, which is suitable for producing integrated external wall thermal insulation prefabricated wallboard. BACKGROUND

[0002] Foam concrete is widely used in building external wall insulation materials due to its light weight, thermal insulation, sound insulation and other characteristics. However, traditional foam concrete has low tensile strength, poor crack resistance, insufficient forming precision, fiber aggregation and uneven pore distribution, which limits its application in high-performance prefabricated wallboard. In recent years, fiber reinforcement and rubber particle doping technology have been introduced to improve the mechanical properties and functionality of foam concrete, but the dynamic control problem in the forming process has not been solved. Vibration or vacuum technology is mostly used alone, and lacks synergistic optimization. In view of the above shortcomings, there is an urgent need for a self-adaptive vibration-vacuum composite mold pressing prefabricated wallboard preparation process to improve the forming precision and performance of the wallboard through dynamic parameter control and new modified formulations. SUMMARY

[0003] In view of the above technical deficiencies, the purpose of the present application is to provide a self-adaptive vibration-vacuum composite mold pressing prefabricated wallboard preparation process to improve crack resistance, thermal insulation performance, and high forming precision.

[0004] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0005] A self-adaptive vibration-vacuum composite mold pressing prefabricated wallboard preparation process, comprising the following steps:

[0006] 1) Prepare raw materials: select polypropylene fibers with a length of 6 mm, 10 mesh and 40 mesh rubber particles, sodium dodecyl sulfate foaming agent, sulphoaluminate cement-based material and silane-nano silica composite modifier;

[0007] 2) Modification: mix the rubber particles with the silane-nano silica composite modifier and ultrasonic treatment;

[0008] 3) Slurry premixing: after low-speed stirring of the modified rubber particles and the sulphoaluminate cement-based material, add the polypropylene fibers;

[0009] 4) Foaming and mixing: prepare foam with sodium dodecyl sulfate foaming agent and add it to the premixed slurry to form foam concrete slurry;

[0010] 5) Self-adaptive vibration-vacuum composite mold pressing: layer pouring, PLC control vibration frequency 50-80Hz and vacuum degree 0.02-0.04MPa;

[0011] 6) Curing and demolding: adding early strength agent to maintain the prefabricated wallboard.

[0012] Preferably, the tensile strength of the polypropylene fiber is ≥500 MPa, and the dosage is 0.5-0.7% by volume fraction.

[0013] Preferably, the rubber particles are waste tire rubber particles, the total dosage is 8-10% by mass ratio, the mass ratio of 10 mesh and 40 mesh rubber particles is 1:1.2, and the dosage of silane-nano silicon dioxide composite modifier is 0.3-0.5%.

[0014] Preferably, the ultrasonic treatment frequency is 25-30 kHz, and the treatment time is 3 minutes.

[0015] Preferably, the thickness of each layer of the layered pouring is 20-30 mm, the vibration frequency error is ±5 Hz, and the vacuum degree is 0.02-0.04 MPa.

[0016] Preferably, the early strength agent is calcium aluminate cement, the dosage is 5% of the total cement mass, and the curing condition is humidity 95% and temperature 22-25℃.

[0017] Preferably, the size deviation of the prefabricated wallboard prepared is ±0.8 mm, the compressive strength is 9.2 MPa, the tensile strength is 1.8 MPa, the thermal conductivity is 0.09 W / (m·K), and the fiber agglomeration rate is ≤5%.

[0018] Compared with the prior art, the beneficial effects of the present application are as follows:

[0019] High mechanical properties: the compressive strength of the product is increased by 15% (up to 8-10 MPa), the tensile strength is increased by 20% (up to 1.5-2 MPa), and the crack resistance is significantly improved.

[0020] Excellent thermal insulation performance: the thermal conductivity is reduced to 0.08-0.10 W / (m·K), which meets the external wall insulation requirements.

[0021] High-precision forming: the size deviation of the product is controlled within ±1 mm, and the surface finish is improved by 10%.

[0022] High efficiency: the production cycle is shortened by 30% (from the traditional 24 hours to 8 hours demolding + 7 days curing). BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The process flow chart of the present application;

[0024] Figure 2 The effect comparison chart of the preparation process of the present application and the traditional preparation process. DETAILED DESCRIPTION

[0025] The application will be further described in conjunction with the accompanying drawings.

[0026] As Figure 1 , Figure 2 shown, a preparation process of adaptive vibration-vacuum composite die pressing prefabricated wallboard, comprising the following steps:

[0027] 1) Raw material preparation:

[0028] Polymer fiber: polypropylene fiber is selected, with a length of 6 mm and a density of 0.91 g / cm 3 , tensile strength ≥ 500 MPa.

[0029] Rubber particles: waste tire rubber particles with particle sizes of 10 mesh (2 mm) and 40 mesh (0.425 mm) are used, with a mass ratio of 1:1.

[0030] Foaming agent: sodium dodecyl sulfate is used, with a concentration of 0.3-0.5% (mass ratio), for generating uniform micropores.

[0031] Matrix material: ordinary Portland cement, fly ash, silica fume and water, with a mixing ratio of 1:0.3:0.1:0.5.

[0032] 2) Slurry premixing:

[0033] Mix 10 mesh and 40 mesh rubber particles with cement, fly ash and silica fume, and add water for low-speed stirring (100-150 rpm, 5 minutes) to fully wet the surface of the rubber particles.

[0034] Add polymer fibers and use variable frequency stirring (200-300 rpm, 3 minutes) to ensure uniform dispersion of the fibers.

[0035] 3) Foaming and slurry mixing:

[0036] Mix the sodium dodecyl sulfate foaming agent with water at a ratio of 1:30, and use a high-speed foaming machine (1000 rpm) to prepare foam.

[0037] Slowly add the foam to the premixed slurry and use low-speed stirring (80-100 rpm, 2 minutes) to form a uniform foam concrete slurry.

[0038] 4) Vibration-vacuum composite die pressing:

[0039] Use a special mold with a vibration device and a vacuum suction system, with a vibration frequency of 50-100 Hz and a vacuum degree of 0.01-0.05 MPa.

[0040] The foam concrete slurry is layered and cast in the mold, each layer has a casting thickness of 20-30 mm, and the vibration time is 30-60 seconds to remove internal bubbles and improve the density.

[0041] The vacuum suction removes excess water, and the suction time is 1-2 minutes to reduce the risk of shrinkage cracking.

[0042] 5) Curing and demolding:

[0043] Sulphoaluminate cement (5% of the total cement mass) is added as a fast curing agent, and the mold is maintained at room temperature for 8 hours.

[0044] After demolding, the product is cured in an environment with a humidity of 95% and a temperature of 20-25°C for 7 days to obtain an integrated external wall insulation prefabricated wall panel.

[0045] Example 1: Standard process

[0046] Raw materials: polypropylene fiber (6 mm, 0.6% by volume), 10 mesh and 40 mesh rubber particles (total dosage 9% by mass, 1:1.2), sodium dodecyl sulfate (0.5%), silane-nano silica (0.4%), and the same as the scheme.

[0047] Process parameters: vibration frequency 70 Hz, vacuum degree 0.03 MPa, layer thickness 25 mm, ultrasonic modification 25 kHz.

[0048] Results: The prefabricated wall panel (size 1000×500×100 mm) is prepared, with a size deviation of ±0.8 mm, a compressive strength of 9.2 MPa, a tensile strength of 1.8 MPa, a thermal conductivity of 0.09 W / (m·K), and a fiber agglomeration rate of 4.5%.

[0049] Example 2: High fiber content process

[0050] Raw materials: polypropylene fiber (6 mm, 0.7% by volume), rubber particles (total dosage 8% by mass, 1:1.2), silane-nano silica (0.5%), and the same as Example 1.

[0051] Process parameters: vibration frequency 75 Hz, vacuum degree 0.04 MPa, layer thickness 20 mm, ultrasonic modification 30 kHz.

[0052] Results: Size deviation ±0.7 mm, compressive strength 8.8 MPa, tensile strength 1.9 MPa, thermal conductivity 0.10 W / (m·K), and fiber agglomeration rate 4%.

[0053] Technical core:

[0054] Adaptive vibration-vacuum technology: dynamically adjust vibration frequency and vacuum degree by PLC, optimize forming parameters according to slurry viscosity, improve pore uniformity and size accuracy.

[0055] Silane-nano silica composite modification: significantly enhance the interfacial bonding force between rubber particles and cement matrix, improve crack resistance and durability.

[0056] Layered pouring optimization: 20-30mm per layer combined with adaptive control, ensuring consistency of large wall panels (1000×500×100mm).

Claims

1. A process for the preparation of self-adapting vibration-vacuum combined die-pressed precast wall panels, characterized by, The method comprises the following steps: 1) preparing raw materials: selecting polypropylene fibers with a length of 6 mm, rubber particles with 10 mesh and 40 mesh, sodium dodecyl sulfate foaming agent, sulphoaluminate cement-based material and silane-nano-silica composite modifier; 2) modification treatment: mixing rubber particles with silane-nano-silica composite modifier and ultrasonic treatment; 3) slurry premixing: adding polypropylene fibers after low-speed stirring of modified rubber particles and sulphoaluminate cement-based material; 4) foaming and mixing: preparing foam with sodium dodecyl sulfate foaming agent and adding it into the premixed slurry to form foam concrete slurry; 5) self-adaptive vibration-vacuum composite mould pressing: layering pouring, PLC control vibration frequency 50-80 Hz and vacuum degree 0.02-0.04 MPa; 6) curing and demoulding: adding early strength agent for curing to obtain a prefabricated wallboard.

2. The process for preparing self-adapting vibration-vacuum compound mould pressing precast wallboard according to claim 1, characterized in that, The tensile strength of the polypropylene fiber is ≥500 MPa, and the dosage is 0.5-0.7% volume fraction.

3. The process for preparing self-adapting vibration-vacuum compound mould pressing precast wallboard according to claim 1, characterized in that, The rubber particles are waste tire rubber particles, and the total dosage is 8-10% by mass; the mass ratio of 10 mesh and 40 mesh rubber particles is 1:1.2, and the dosage of silane-nano-silica composite modifier is 0.3-0.5%.

4. The process for preparing self-adapting vibration-vacuum compound mould pressing precast wallboard according to claim 1, characterized in that, The ultrasonic treatment frequency is 25-30 kHz, and the treatment time is 3 minutes.

5. The process for preparing self-adapting vibration-vacuum compound mould pressing precast wallboard according to claim 1, characterized in that, The layering pouring is 20-30 mm thick for each layer, the vibration frequency error is ±5 Hz, and the vacuum degree is 0.02-0.04 MPa.

6. The process for preparing self-adapting vibration-vacuum compound die-pressed precast wallboard according to claim 1, characterized in that, The early strength agent is calcium aluminate cement, and the dosage is 5% of the total cement mass; the curing condition is 95% humidity and 22-25℃ temperature.

7. The process according to any one of claims 1-6, wherein the self-adapting vibration-vacuum compound moulding process for manufacturing prefabricated wall panels is characterized by, The size deviation of the obtained prefabricated wallboard is ±0.8 mm, the compressive strength is 9.2 MPa, the tensile strength is 1.8 MPa, the thermal conductivity is 0.09 W / (m·K), and the fiber agglomeration rate is ≤5%.

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