Method for manufacturing a precast ceramic concrete composite floor

Abstract

The application relates to the field of concrete prefabricated floors, and particularly discloses a preparation method of a ceramsite concrete prefabricated composite floor. The preparation method of the ceramsite concrete prefabricated composite floor comprises the following steps: (1) applying a release agent in a prefabricated composite floor mold, and then installing embedded parts and a steel mesh; (2) manufacturing a steel mesh protection layer; (3) pouring, after pouring is completed, placing a wood board above the mold, using an up-down type vibrator to vibrate the ceramsite in the concrete towards the bottom of the mold, the vibration time being 10-20 min, and after the vibration is completed, the wood board is removed; then manually smoothing the pouring surface; (4) after the pouring surface is smoothed, spraying a rapid hardening agent, and after hardening, the mold is removed to obtain the prefabricated composite floor. The method can effectively reduce the phenomenon that the ceramsite in the prefabricated composite floor concrete appears to float upwards, so that the prefabricated composite floor can be ensured to have good quality.

Description

Technical Field

[0001] This application relates to the field of precast concrete floor slabs, and more specifically, it relates to a method for preparing a precast composite floor slab made of ceramsite concrete. Background Technology

[0002] Precast concrete slabs are a common building material, mainly used in the construction and decoration of buildings. Their manufacturing process is usually completed in a factory, and their specifications, dimensions, and shapes can be pre-defined for rapid installation and assembly on the construction site.

[0003] Precast concrete floor slabs offer numerous advantages. Firstly, they significantly shorten construction time, as most manufacturing is completed in the factory, requiring only simple installation and assembly on-site. Secondly, these slabs possess high strength and durability, meeting the load-bearing requirements of buildings and withstanding the test of time. Furthermore, precast concrete floor slabs offer excellent thermal insulation and soundproofing properties, effectively improving building comfort and energy efficiency.

[0004] In related technologies, ceramsite concrete is mostly used for precast composite floor slabs. Because ceramsite concrete is a lightweight material, its density is approximately one-third to one-quarter that of traditional concrete. Therefore, using ceramsite concrete can reduce the self-weight of the floor slab. Its lightweight nature also makes transportation and installation relatively convenient, significantly reducing construction time. Furthermore, ceramsite concrete has a low thermal conductivity, providing effective heat insulation and good thermal insulation performance, which helps improve building energy efficiency.

[0005] However, in related technologies, when using expanded clay concrete to prepare precast composite floor slabs, the expanded clay particles in the concrete are prone to floating, which leads to uneven composition inside the precast floor slab and thus affects the product quality of the precast floor slab. Summary of the Invention

[0006] To avoid the floating of expanded clay aggregate in the precast floor slabs during the preparation of expanded clay aggregate concrete, this application provides a method for preparing precast composite floor slabs made of expanded clay aggregate concrete.

[0007] In a first aspect, this application provides a method for preparing precast composite floor slabs made of ceramsite concrete, employing the following technical solution:

[0008] A method for preparing a precast composite floor slab made of ceramsite concrete includes the following steps:

[0009] (1) Apply release agent to the mold of precast composite floor slab, then fix the embedded junction box and embedded parts, and then place the steel mesh; (2) The steel mesh is fixed on the mold by plastic fasteners to form a steel mesh protective layer;

[0010] (3) Pour the prepared ceramsite concrete continuously into the mold from above. After pouring, place a wooden board on top of the mold and use an up-and-down vibrator to vibrate the ceramsite in the concrete toward the bottom of the mold for 10-20 minutes. After vibration, remove the wooden board and then manually smooth the pouring surface.

[0011] (4) After smoothing the pouring surface, spray a layer of quick-setting agent on the surface of the ceramsite concrete, and then remove the formwork after the ceramsite concrete has completely hardened to obtain the precast composite floor slab.

[0012] By adopting the above technical solution and preparation method, after pouring, the floating ceramsite is vibrated towards the bottom of the mold using an upper and lower vibrator. This effectively prevents the ceramsite from floating in the concrete. The wooden board allows for synchronous vibration inside the mold and avoids the segregation problem that can occur with conventional contact vibration. After vibration, a quick-setting agent is sprayed onto the concrete surface to accelerate cement hydration and hardening, promoting rapid concrete solidification and preventing the ceramsite from floating in the vibrated concrete. This method effectively reduces the floating of ceramsite in precast composite floor slabs, thus ensuring good quality of the precast composite floor slabs.

[0013] Optionally, the ceramsite concrete comprises the following raw materials in parts by weight:

[0014] 300-380 parts cement;

[0015] 80-120 parts fly ash;

[0016] 70-90 parts mineral powder;

[0017] 600-700 parts sand;

[0018] 500-750 parts of expanded clay aggregate;

[0019] 250-300 portions of micro-nano CO2 bubble water;

[0020] 20-50 parts tourmaline powder;

[0021] 80-120 parts water.

[0022] By employing the above technical solution, micro-nano CO2 bubble water is introduced into concrete. Because the surface of the micro-nano bubbles is charged, their adsorption capacity is strong. When the nano-bubbles adsorb Ca from the surrounding solution... 2+ OH - H3SiO 4-When these micro- and nano-sized CO2 bubbles are present, Ca(OH)2 precipitate and CSH gel precipitate are rapidly formed. Therefore, these micro- and nano-sized bubbles can accelerate the early hydration process of cement and increase the hydration products, thus accelerating the hardening time of the expanded clay concrete. Furthermore, due to the large amount of water contained in the micro- and nano-sized CO2 bubbles and their low density, they further help to inhibit the floating of expanded clay particles in the concrete slurry.

[0023] Because the micro-nano CO2 bubble water is prone to bursting during the pouring process, tourmaline powder is added. Due to the thermoelectric effect, when the ambient temperature changes, the charged particles in the crystal of tourmaline powder undergo relative displacement, and the positive and negative charge centers separate, thereby generating a large number of negative ions. The exothermic reaction of cement hydration provides a good external condition for the tourmaline powder to generate negative ions. The negative ions generated by the tourmaline powder cause a large number of negative charges to adhere to the gas-water interface of the micro-nano bubbles, ultimately enabling the zeta potential of the micro-nano bubble water in the concrete to reach -50mV. The zeta potential of general colloids is greater than -30mV and is easier to stabilize. Therefore, the addition of tourmaline powder effectively avoids the problem of bubble bursting in micro-nano CO2 bubble water, which helps to maintain a low density after pouring, and thus helps to suppress the problem of ceramsite floating.

[0024] Optionally, the tourmaline powder is preferably magnesium tourmaline powder.

[0025] By adopting the above technical solution, the use of magnesium tourmaline powder can reduce the introduction of alkaline ions such as sodium and potassium, thereby effectively reducing the alkali-aggregate reaction of ceramsite concrete, which is conducive to maintaining the good quality of precast composite floor slabs.

[0026] Optionally, the particle size of the magnesium tourmaline powder is 38-45 micrometers.

[0027] By adopting the above technical solution, the thermoelectric effect of tourmaline tends to increase as its powder particle size decreases, and it has a series of excellent surface and interface properties. However, due to the large specific surface area and high specific surface energy of the powder particles, agglomeration is very easy to occur during preparation and processing, resulting in uneven dispersion of tourmaline in the concrete system. Therefore, selecting the particle size of magnesium tourmaline powder within the above range can maintain a good balance between thermoelectric effect and dispersibility, thereby fully improving the construction quality of ceramsite concrete.

[0028] Optionally, the bubble D50 of the micro-nano CO2 bubble water is 138-150nm.

[0029] By adopting the above technical solution and controlling the diameter of micro- and nano-bubbles, the existence time in concrete can be guaranteed. Since large-diameter bubbles are easy to escape, while micro- and nano-bubbles rise very slowly in the slurry, the process from generation to escape and rupture usually takes a period of time, thus meeting the requirements for the effectiveness of concrete mixing.

[0030] Optionally, the quick-setting agent comprises the following raw materials in parts by weight:

[0031] 40-60 parts aluminum sulfate solution;

[0032] 10-15 parts urea;

[0033] 3-5 parts silica sol;

[0034] 12-15 parts of D-erythritol;

[0035] 30-50 parts water.

[0036] By adopting the above technical solution, the retarder of the above components can effectively accelerate the setting and hardening process of cement, so as to form sufficient strength in a very short time, thereby preventing the floating of ceramsite in uniformly vibrated concrete. By adding D-erythritol, which has excellent permeability in alkaline concrete slurry systems, it helps the accelerator to fully penetrate into the concrete, thus significantly accelerating the hardening of the concrete. On the other hand, D-erythritol reacts with cement molecules to produce a viscous substance, thereby reducing the fluidity and diffusivity of the concrete slurry, further effectively inhibiting the floating of ceramsite in the slurry.

[0037] Optionally, the mass concentration of the aluminum sulfate solution is 35-45%.

[0038] Secondly, this application provides a precast composite floor slab made of ceramsite concrete, which is prepared using the above-mentioned preparation method.

[0039] By adopting the above technical solution and the above method, the precast composite floor slabs are lightweight, easy to install and transport, and have uniform internal aggregate distribution, thus possessing good strength and rigidity, meeting the construction needs of precast floor slabs and facilitating the completion of the interlocking construction cycle.

[0040] In summary, this application has the following beneficial effects:

[0041] 1. Due to the preparation method of this application, after pouring, the floating ceramsite is vibrated towards the bottom of the mold using an upper and lower vibrator, which effectively prevents the ceramsite in the concrete from floating. The wooden board allows for synchronous vibration inside the mold and avoids the segregation problem that can occur with conventional contact vibration. After vibration, a quick-setting agent is sprayed on the concrete surface to accelerate cement hydration and hardening, promoting rapid concrete solidification and preventing the ceramsite in the vibrated concrete from floating. The above method effectively reduces the floating of ceramsite in the concrete of precast composite floor slabs, thus ensuring good quality of the precast composite floor slabs.

[0042] 2. The concrete prepared in this application uses micro-nano CO2 bubble water. Since micro-nano bubbles can accelerate the early hydration reaction process of cement and correspondingly increase hydration products, this is beneficial for accelerating the hardening time of the ceramsite concrete. Furthermore, because the amount of micro-nano CO2 bubble water is relatively large and its density is low, it helps to further suppress the floating of ceramsite in the concrete slurry.

[0043] 3. The method of this application, by using a retarder, can fully accelerate the hardening of concrete. On the other hand, the D-erythritol in the retarder reacts with cement molecules to produce a viscous substance, thereby reducing the fluidity and diffusivity of the concrete slurry, and thus further effectively inhibiting the floating of ceramsite in the slurry. Detailed Implementation

[0044] The present application will be further described in detail below with reference to the embodiments.

[0045] All raw materials used in this embodiment were obtained commercially, and the sand particle size was 0.35-0.5mm.

[0046] Example of preparation of ceramsite concrete

[0047] Preparation Example 1

[0048] A type of ceramsite concrete, the raw material composition and dosage are shown in Table 1, wherein the particle size of magnesium tourmaline powder is 38-45 micrometers; and the bubble D50 of micro-nano CO2 bubble water is 138nm.

[0049] Lightweight aggregate concrete is prepared using the following method:

[0050] S1. Mix cement, fly ash, mineral powder, sand, ceramsite, and magnesium tourmaline powder, and stir for 20 minutes to obtain ready-mixed concrete; S2. Mix the ready-mixed concrete with micro-nano CO2 bubble water and water, and stir for 3 minutes to obtain ceramsite concrete. Example 2: Preparation of Ceramsite Concrete

[0051] A type of ceramsite concrete differs from Preparation Example 1 in that its raw material composition and dosage are different, as shown in Table 1. The particle size of the magnesium tourmaline powder is 38-45 micrometers; the bubble D50 of the micro-nano CO2 bubble water is 145 nm.

[0052] Preparation Example 3

[0053] A type of ceramsite concrete differs from Preparation Example 1 in that its raw material composition and dosage are different, as shown in Table 1. The particle size of the magnesium tourmaline powder is 38-45 micrometers; the bubble D50 of the micro-nano CO2 bubble water is 150 nm.

[0054] Preparation Example 4

[0055] A type of expanded clay concrete differs from preparation example 3 in that it uses an equal amount of water instead of micro-nano CO2 bubble water in its raw materials.

[0056] Table 1. Concrete components and dosages (kg) in each preparation example.

[0057]

[0058] Preparation example of accelerator

[0059] Preparation Example 5

[0060] A quick-setting agent, the raw material components and dosages of which are shown in Table 2, wherein the mass concentration of aluminum sulfate solution is 35%.

[0061] The quick-setting agent was prepared using the following method:

[0062] A quick-setting agent is obtained by mixing aluminum sulfate solution, urea, silica sol, D-erythritol and water and stirring for 2 minutes.

[0063] Preparation Example 6

[0064] A quick-setting agent, which differs from Preparation Example 5 in that its raw material composition and dosage are different, as shown in Table 1, wherein the mass concentration of aluminum sulfate solution is 40%.

[0065] Preparation Example 7

[0066] A quick-setting agent, which differs from Preparation Example 5 in its raw material composition and dosage, as shown in Table 1, wherein the mass concentration of aluminum sulfate solution is 45%.

[0067] Preparation Example 8

[0068] A quick-setting agent, which differs from Preparation Example 7 in that D-erythritol was not added to the raw materials.

[0069] Table 1. Components and dosage (kg) of the accelerator in each preparation example.

[0070]

[0071]

[0072] Example

[0073] Example 1

[0074] A method for preparing a precast composite floor slab made of ceramsite concrete includes the following steps:

[0075] (1) Apply release agent to the mold of precast composite floor slab, then fix the embedded junction box and embedded parts, and then place the steel mesh; (2) The steel mesh is fixed on the mold by plastic fasteners to form a steel mesh protective layer;

[0076] (3) The prepared ceramsite concrete is continuously poured into the mold from above. After pouring, a wooden board is placed on top of the mold, and an up-and-down vibrator is used to vibrate the ceramsite in the concrete towards the bottom of the mold for 10 minutes. After vibration, the wooden board is removed. Then the pouring surface is smoothed manually. The ceramsite concrete used is the ceramsite concrete prepared in Preparation Example 1.

[0077] (4) After smoothing the pouring surface, spray a layer of quick-setting agent on the surface of the ceramsite concrete, and then remove the formwork after the ceramsite concrete has completely hardened to obtain the precast composite floor slab; the quick-setting agent used is the quick-setting agent prepared in Preparation Example 5.

[0078] Example 2

[0079] A method for preparing a precast composite floor slab made of ceramsite concrete includes the following steps:

[0080] (1) Apply release agent to the mold of precast composite floor slab, then fix the embedded junction box and embedded parts, and then place the steel mesh; (2) The steel mesh is fixed on the mold by plastic fasteners to form a steel mesh protective layer;

[0081] (3) The prepared ceramsite concrete is continuously poured into the mold from above. After pouring, a wooden board is placed on top of the mold, and an up-and-down vibrator is used to vibrate the ceramsite in the concrete towards the bottom of the mold for 15 minutes. After vibration, the wooden board is removed. Then the pouring surface is smoothed manually. The ceramsite concrete used is the ceramsite concrete prepared in Preparation Example 2.

[0082] (4) After smoothing the pouring surface, spray a layer of quick-setting agent on the surface of the ceramsite concrete, and then remove the formwork after the ceramsite concrete has completely hardened to obtain a precast composite floor slab; wherein the quick-setting agent is the quick-setting agent prepared in Preparation Example 6.

[0083] Example 3

[0084] A method for preparing a precast composite floor slab made of ceramsite concrete includes the following steps:

[0085] (1) Apply release agent to the mold of precast composite floor slab, then fix the embedded junction box and embedded parts, and then place the steel mesh; (2) The steel mesh is fixed on the mold by plastic fasteners to form a steel mesh protective layer;

[0086] (3) The prepared ceramsite concrete is continuously poured into the mold from above. After pouring, a wooden board is placed on top of the mold, and an up-and-down vibrator is used to vibrate the ceramsite in the concrete towards the bottom of the mold for 20 minutes. After vibration, the wooden board is removed. Then the pouring surface is smoothed manually. The ceramsite concrete used is the ceramsite concrete prepared in Preparation Example 3.

[0087] (4) After smoothing the pouring surface, spray a layer of quick-setting agent on the surface of the ceramsite concrete, and then remove the formwork after the ceramsite concrete has completely hardened to obtain the precast composite floor slab; the quick-setting agent used is the quick-setting agent prepared in Preparation Example 7.

[0088] Example 4

[0089] A method for preparing a precast composite floor slab of ceramsite concrete, which differs from Example 1 in that the concrete in step (3) is ceramsite concrete prepared in Example 4.

[0090] Example 5

[0091] A method for preparing a precast composite floor slab of ceramsite concrete differs from Example 1 in that the accelerator in step (4) is the accelerator obtained in Preparation Example 8.

[0092] Comparative Example

[0093] Comparative Example 1

[0094] A method for preparing a precast composite floor slab of ceramsite concrete differs from Example 1 in step (3). Specifically: (3): The prepared ceramsite concrete is continuously poured into the mold from above. After pouring, the pouring surface is manually smoothed. The ceramsite concrete used is the ceramsite concrete prepared in Example 1.

[0095] Comparative Example 2

[0096] A method for preparing a precast composite floor slab made of ceramsite concrete differs from Example 1 in step (4). Specifically, (4) after smoothing the pouring surface, the formwork is removed after the ceramsite concrete has fully hardened to obtain the precast composite floor slab.

[0097] Performance testing

[0098] Test 1 Appearance Inspection Test Method: After the precast composite floor slab is demolded, the inspectors observe the distribution of ceramsite on the side wall of the precast floor slab and record it in Table 3.

[0099] Test subjects: precast floor slabs prepared in Examples 1-5 and Comparative Examples 1-2.

[0100] Test 1 Strength Test Method: The precast composite floor slab was subjected to a maximum load test according to the method specified in GB / T 24497-2009 Performance Standard for Buildings - Performance Test of Precast Concrete Floor Slabs under Concentrated Load Conditions. The test results are shown in Table 3.

[0101] Test subjects: precast floor slabs prepared in Examples 1-5 and Comparative Examples 1-2.

[0102] Table 3. Experimental Results

[0103]

[0104]

[0105] As can be seen from Examples 1-3 and Comparative Example 1, the precast composite floor slabs prepared in Examples 1-3 of this application have a maximum load of approximately 38 MPa, and the expanded clay aggregates on the end face of the floor slab are evenly distributed without any floating phenomenon, thus enabling the precast composite floor slab to maintain good strength performance. However, in Comparative Example 1, because the expanded clay aggregate concrete was not vibrated after pouring, the expanded clay aggregates in the precast floor slab floated to the surface, and the cementitious materials and aggregates separated, resulting in a maximum load of only 16.7 MPa for the precast floor slab.

[0106] Combining Example 4 and Example 1, it can be seen that in the ceramsite concrete used in Example 4, since no micro-nano CO2 bubble water was added, the ceramsite tends to float in the concrete system. As a result, the ceramsite is more dense at the top of the floor slab and more sparse at the bottom, which leads to a reduction in the maximum load of the precast composite floor slab.

[0107] As can be seen from the combination of Example 5 and Example 1, the quick-setting agent used in Example 4 did not contain D-erythritol, which resulted in the quick-setting agent not being able to exert a good effect in promoting hardening. Therefore, after vibration, the ceramsite still floated, making the ceramsite more dense at the top of the floor slab and more sparse at the bottom, and the maximum load of the floor slab was also reduced.

[0108] As can be seen from Comparative Example 2 and Example 1, since Comparative Example 2 did not perform the operation of spraying quick-setting agent for curing, the concrete still exhibited the phenomenon of floating during the slow hardening process after vibration, which led to a decrease in the maximum load of the precast composite floor slab.

[0109] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a precast composite floor slab made of ceramsite concrete, characterized in that, Includes the following steps: (1) Apply release agent to the mold of precast composite floor slab, then fix the embedded junction box and embedded parts, and then place the steel mesh; (2) The steel mesh is fixed to the mold by plastic fasteners to form a protective layer for the steel mesh; (3) Pour the prepared ceramsite concrete continuously into the mold from above. After pouring, place a wooden board on top of the mold and use an up-and-down vibrator to vibrate the ceramsite in the concrete toward the bottom of the mold. The vibration time is 10-20 minutes. After vibration, remove the wooden board and then manually smooth the pouring surface. (4) After smoothing the pouring surface, spray a layer of quick-setting agent on the surface of the ceramsite concrete, and then remove the formwork after the ceramsite concrete has completely hardened to obtain the precast composite floor slab. The expanded clay concrete comprises the following raw materials in parts by weight: 300-380 parts cement; 80-120 parts fly ash; 70-90 parts mineral powder; 600-700 parts sand; 500-750 parts expanded clay; 250-300 parts micro-nano CO2 bubble water; 20-50 parts magnesium tourmaline powder; and 80-120 parts water. The particle size of the magnesium tourmaline powder is 38-45 micrometers; The quick-setting agent comprises the following raw materials in parts by weight: 40-60 parts aluminum sulfate solution; 10-15 parts urea; 3-5 parts silica sol; 12-15 parts D-erythritol; and 30-50 parts water.

2. The method for preparing a precast composite floor slab of expanded clay aggregate concrete according to claim 1, characterized in that: The bubble D50 of the micro-nano CO2 bubble water is 138-150nm.

3. The method for preparing a precast composite floor slab of expanded clay aggregate concrete according to claim 1, characterized in that: The mass concentration of the aluminum sulfate solution is 35-45%.

4. A precast composite floor slab made of ceramsite concrete, characterized in that: It is prepared by the preparation method according to any one of claims 1-3.

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