Low-cement subway evacuation platform slab and preparation method thereof

Abstract

The present invention relates to the field of subway construction technology, and specifically discloses a low-cement subway evacuation platform board. The raw materials include, by weight, 300-400 parts of kaolin, 260-280 parts of cement, 50-60 parts of silica fume, 300-400 parts of medium sand, 1000-1050 parts of rice stone, 5-7 parts of basalt fiber, 1-2 parts of polycarboxylate water-reducing agent, 16-18 parts of epichlorohydrin rubber particles, and 150-200 parts of water. The subway evacuation platform board of the present invention has good high temperature resistance and fire resistance, high compressive strength, high elastic modulus, long service life, can be applied in various scenarios, is not easy to damage, and has low cost.

Description

Technical Field

[0001] The invention relates to the technical field of subway construction, in particular to a low-cement subway evacuation platform slab and a preparation method thereof. Background Art

[0002] Subway evacuation platforms are dedicated passages for evacuating passengers in the event of an emergency while operating a subway train in a tunnel. When an emergency occurs within a train section, passengers can use these evacuation platforms to reach the station or escape through inter-section communication passages. To improve subway safety, many cities have dedicated emergency evacuation platforms in their subway tunnels, and all subways under construction in China have them installed.

[0003] Currently, the materials used in evacuation platforms are gradually shifting from steel structures, cement-based materials, and composite materials to reactive powder concrete (RPC). Ultra-high performance concrete (UPC) offers advantages such as high temperature resistance, fire resistance, durability, corrosion resistance, and high compressive strength. It uses no coarse aggregate, but silica fume and fiber (steel fiber or composite organic fiber). However, it requires a high cement content and has a low elastic modulus.

[0004] With the increasing number of urban subway lines and the increasing number of new subway line plans each year, there are already seven cities with subway lines exceeding 500 kilometers in total. The cost of subway evacuation platforms is undoubtedly huge. If the amount of cement used can be reduced while ensuring the fire resistance, high temperature resistance, and high strength of the evacuation platform, the cost of building materials can be greatly saved, which has extremely high economic benefits. In summary, there is an urgent need for a subway evacuation platform board with low cement content and low cost. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a subway evacuation platform plate that at least achieves the effects of fire resistance, high temperature resistance, high compressive strength, large elastic modulus and long service life.

[0006] The object of the present invention is achieved through the following technical solutions:

[0007] A subway evacuation platform slab comprises, by weight, 300-400 parts of kaolin, 260-280 parts of cement, 50-60 parts of silica fume, 300-400 parts of medium sand, 1000-1050 parts of rice stone, 5-7 parts of basalt fiber, 1-2 parts of polycarboxylate water-reducing agent, 16-18 parts of epichlorohydrin rubber particles, and 150-200 parts of water.

[0008] Furthermore, the particle size of the kaolin is 80-100 mesh.

[0009] Furthermore, the cement is 625 refractory cement.

[0010] Furthermore, the silica fume is at least one of Grade I silica fume and Grade II silica fume;

[0011] And / or, the silica content of the silica fume is greater than 85%.

[0012] Furthermore, the rice stone is basalt sandstone with a particle size of 5-8 mm.

[0013] Furthermore, the medium sand is zone 2 medium sand, including at least one of basalt machine-made sand, ordinary river sand and washed river sand.

[0014] Furthermore, the surface of the subway evacuation platform board is provided with an anti-slip pattern.

[0015] Furthermore, steel bars are provided inside the subway evacuation platform slab.

[0016] Furthermore, the method for preparing the subway evacuation platform plate comprises the following steps:

[0017] S1: adding the raw materials in the order of rice stone, medium sand, epichlorohydrin rubber particles, kaolin, cement, silica fume, basalt fiber, polycarboxylate water reducer and water into a stirring device for mixing and stirring for 5 minutes to obtain a dispersed concrete;

[0018] S2: pouring the evacuated concrete into a reinforced mold, vibrating it, and then curing and demoulding it.

[0019] Furthermore, the mold is a flat mold or a vertical mold.

[0020] Furthermore, the reinforcement method is a conventional reinforcement method in this field.

[0021] It is noteworthy that the present invention is a prefabricated concrete panel that can be fixed by steel beams and anchor bolts during installation.

[0022] It is worth noting that the current price of ordinary Portland cement is about 400 yuan / ton, while kaolin is a very common clay mineral. Even kaolin that has been finely ground and calcined costs only about 300 yuan / ton. The present invention uses kaolin that has only been coarsely ground, and the cost does not exceed 100 yuan / ton. If kaolin can be used to replace part of the cement in concrete, a lot of costs can be saved.

[0023] However, because kaolin is weaker than cement, the present invention incorporates a small amount of epichlorohydrin rubber. This rubber exhibits excellent fire and high-temperature resistance, and can increase the toughness and compressive strength of concrete, ensuring that the concrete slabs with kaolin still have high strength, meeting product requirements. Although epichlorohydrin rubber currently costs approximately 5,000 yuan per ton, the low amount used, approximately 1 / 20 of the cement content, still results in a significantly lower cost than RPC concrete slabs.

[0024] The beneficial effects of the present invention are:

[0025] 1. The subway evacuation platform slab of the present invention has a lower cement content and lower raw material cost than the RPC concrete slab, and the preparation method is simple, which is suitable for large-scale production.

[0026] 2. The subway evacuation platform board of the present invention has good high temperature resistance and fire resistance, high compressive strength, high elastic modulus, long service life, can be applied to various scenarios, and is not easy to damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a sample photo of the subway evacuation platform of the present invention;

[0028] Figure 2 This is the reinforcement diagram of the 1500*900*50 concrete slab described in Example 1. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0030] Example 1

[0031] Prepare a subway evacuation platform board, the steps are as follows:

[0032] Prepare the ingredients:

[0033] Raw kaolin for ceramics was purchased from Guangxi Nanning Jinpinwang Mining Co., Ltd.; 625 refractory cement, brand: China Resources Runfeng; first-grade silica fume (SiO2>85%) for concrete was purchased from Shijiazhuang Daheng Mineral Products Processing Co., Ltd.; basalt machine-made sand and basalt gravel were purchased from Sichuan Zhonghui Yixiao Trading Co., Ltd., with particle sizes ranging from 5 to 8 mm; basalt fiber was purchased from Wuhan Qixing; polycarboxylic acid water-reducing agent was purchased from Nanjing Xinyi Synthetic Technology Co., Ltd.; and chlorohydrin rubber particles were purchased from Handan Congtai District Liangxing Chemical Co., Ltd.

[0034] Prepare concrete:

[0035] 500 kg of basalt stones, 200 kg of river sand, 9 kg of epichlorohydrin rubber particles, 150 kg of coarsely ground kaolin (the raw kaolin is sieved through an 80-mesh sieve), 130 kg of P.O42.5R cement, 30 kg of first-grade silica fume, and 3 kg of basalt fiber are sequentially added into a concrete mixer and pre-mixed for 2 minutes. Then, 1 kg of polycarboxylate water reducer and 100 kg of water are added and stirred for another 3 minutes to obtain concrete material.

[0036] Casting film:

[0037] The concrete material is poured into a vertical mold of 1500mm*900mm*50mm, and the reinforcement in the mold is as follows Figure 2 As shown in the figure, the mechanical properties of the steel bars used are in compliance with the requirements of TB10424. The pouring was completed within 20 minutes. After the pouring was completed, a vibrator was inserted to vibrate and resonate for 3 minutes.

[0038] Maintenance:

[0039] Place the mold in an environment with an ambient temperature of over 10°C and a relative humidity of over 60% for 6 hours. After the initial curing, perform steam curing, maintaining the humidity above 90%. Raise the temperature to 40°C ± 3°C at a rate of 5°C / h and maintain the constant temperature for 24 hours. Then, cool the temperature down at a rate of 5°C / h until the difference between the component surface temperature and the ambient temperature is no more than 20°C. After the initial curing, the evacuation plate can be demoulded. During demoulding, ensure that the difference between the component temperature and the ambient temperature is no more than 15°C. After demoulding, perform final curing in an environment with a humidity of 95% and a relative humidity of 70°C. After 48 hours of final curing, perform natural curing, sprinkling water for curing at an average ambient temperature of around 20°C, for 14 days.

[0040] Example 2

[0041] A subway evacuation platform slab was prepared using the same method as in Example 1, except that the amounts of the raw materials used were: 500 kg of basalt stone, 150 kg of river sand, 8 kg of epichlorohydrin rubber particles, 200 kg of coarsely ground kaolin, 140 kg of P.O42.5R cement, 25 kg of first-grade silica fume, 0.8 kg of polycarboxylate water reducer, and 90 kg of water.

[0042] Example 3

[0043] A subway evacuation platform slab was prepared using the same method as in Example 1, except that the amounts of the raw materials used were: 180 kg of basalt stone, 180 kg of river sand, 8 kg of epichlorohydrin rubber particles, 180 kg of coarsely ground kaolin, 140 kg of P.O42.5R cement, 25 kg of first-grade silica fume, 0.9 kg of polycarboxylate water reducer, and 100 kg of water.

[0044] Experimental Example 1

[0045] Structural load test: The subway evacuation panels obtained in Examples 1-3 were used to produce simulation platforms with a width of 1:1, and simulated on-site installation was performed under a surface load of 5 kN / m 2 Maintain for 1h, surface load 10kN / m 2 Maintain for 30 minutes, with a surface load of 15kN / m 2 After 20 minutes, none of the three evacuation plates experienced any damage or deformation, and no cracks were found on the surface.

[0046] Experimental Example 2

[0047] A concrete material was prepared using the same method as in Example 1, except that kaolin was not added and an equal amount of cement was used instead. The raw materials used were: 500 kg basalt stone, 200 kg river sand, 9 kg epichlorohydrin rubber pellets, 280 kg PO42.5R cement, 30 kg first-grade silica fume, 3 kg basalt fiber, 1 kg polycarboxylate superplasticizer, and 100 kg water.

[0048] The remaining concrete from Examples 1-3 and the comparative concrete were used to prepare 150 mm x 150 mm x 150 mm concrete blocks. After curing for 28 days, mechanical and fire performance tests were conducted. Fire performance tests were conducted in accordance with GB8624-2006, "Classification of Combustion Behavior of Building Materials and Products." The subway evacuation panels from Examples 1-3 and the comparative concrete blocks all achieved A1 rating, demonstrating excellent thermal insulation performance.

[0049] Mechanical Properties Tests: Compressive and tensile strength tests were conducted using the cube compressive strength and splitting compressive strength test procedures described in GB / T 50081-2002 Standard for Mechanical Properties of Ordinary Concrete. Elastic modulus was determined using the secant elastic modulus method. The results are summarized in Table 1.

[0050] Table 1

[0051] Compressive strength / MPa Tensile strength / MPa Elastic modulus / GPa Example 1 34.48 5.83 47.75 Example 2 32.52 5.69 43.18 Example 3 33.40 5.51 44.52 Comparative concrete materials 38.27 4.15 39.47

[0052] The foregoing description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Rather, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the concept described herein through the above teachings or techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the appended claims.

Claims

1. A low-cement subway evacuation platform slab, characterized in that: The raw materials include: by weight, 300-400 parts of kaolin, 260-280 parts of cement, 50-60 parts of silica fume, 300-400 parts of medium sand, 1000-1050 parts of rice stone, 5-7 parts of basalt fiber, 1-2 parts of polycarboxylate water reducer, 16-18 parts of epichlorohydrin rubber particles and 150-200 parts of water; The particle size of the kaolin is 80-100 meshes.

2. The subway evacuation platform plate according to claim 1, characterized in that: The cement is 625 refractory cement.

3. The subway evacuation platform plate according to claim 1, characterized in that: The silica fume is at least one of grade I silica fume and grade II silica fume; And / or, the silica content of the silica fume is greater than 85%.

4. The subway evacuation platform plate according to claim 1, characterized in that: The rice stone is basalt sandstone with a particle size of 5-8 mm.

5. The subway evacuation platform plate according to claim 1, characterized in that: The medium sand is the medium sand in the second zone, including at least one of basalt machine-made sand, ordinary river sand and washed river sand.

6. The subway evacuation platform plate according to claim 1, characterized in that: The surface of the subway evacuation platform plate is provided with an anti-slip pattern.

7. The subway evacuation platform plate according to claim 1, characterized in that: Steel bars are arranged inside the subway evacuation platform plate.

8. The method for preparing a subway evacuation platform slab according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: adding the raw materials in the order of rice stone, medium sand, epichlorohydrin rubber particles, kaolin, cement, silica fume, basalt fiber, polycarboxylate water reducer and water to a stirring device for mixing, stirring for 5 min to obtain evacuated slab concrete; S2: pouring the evacuation slab concrete into a reinforced mold and vibrating it, followed by curing and demoulding.

9. The preparation method according to claim 8, characterized in that: The mold is a flat mold or a vertical mold.

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