Double-layer permeable pavement brick and preparation method thereof

Abstract

The invention relates to a double-layer permeable pavement brick and a preparation method thereof. The double-layer permeable pavement brick comprises a concrete surface layer and a concrete bottom layer which are connected with each other. The concrete surface layer is a permeable layer, the compressive strength grade of the concrete surface layer is C15-C30, and the permeable coefficient is not less than 1cm / s; the concrete bottom layer is a bearing layer, the compressive strength grade of the concrete bottom layer is C60-C80, and a plurality of flow guide pipes penetrating through the concrete bottom layer are arranged on the concrete bottom layer. The concrete surface layer is a pervious concrete layer and can be made into a colored pervious concrete layer according to needs, and decoration is considered; the concrete bottom layer is made of high-performance concrete and is a main bearing structure layer, and the strength and the bearing capacity of the double-layer permeable pavement brick are improved. When it rains, rainwater can flow to a drainage ditch on the road side through the road surface structure on the concrete surface layer and can also infiltrate into the concrete bottom layer through the water permeability of the concrete surface layer and then be discharged through the multiple flow guide pipes, and diversion and permeation of accumulated water on the road surface are accelerated.

Description

Technical Field

[0001] The invention relates to the technical field of pavement bricks, and in particular to a double-layer permeable pavement brick and a preparation method thereof. Background Art

[0002] In recent years, with the continuous advancement of urbanization, the proportion of impermeable ground in cities has continued to rise, weakening the permeability of urban surfaces and causing increasingly serious waterlogging disasters in urban areas. In order to solve the problem of urban waterlogging, the concept of "sponge city" has been proposed, that is, the use of ecological materials such as permeable concrete to achieve permeable pavement on the road surface, which can effectively deal with urban waterlogging and conserve groundwater resources. However, as the main material for permeable pavement, the mechanical properties of permeable concrete are generally low. If the mechanical properties are improved, the permeability will be lost, which greatly limits the widespread application of permeable concrete.

[0003] The strength grade of the currently commonly used pavement bricks is generally C30-C60, and the water permeability coefficient (15℃) is less than 1.0x10 -2 cm / s, poor water permeability. Ordinary permeable concrete has good water permeability, and the water permeability coefficient can generally reach more than 1cm / s, but the compressive strength is low, and the strength grade is generally C15-C30. Directly using permeable concrete to form permeable bricks is not strong enough, which can easily cause the corners of the permeable bricks to collapse, crack, and other damages, reducing the service life of the permeable bricks. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a double-layer permeable pavement brick and a preparation method thereof, which solves the problem that the existing permeable bricks have insufficient permeability and the permeable bricks prepared using highly permeable concrete materials have poor bearing capacity.

[0006] (II) Technical solution

[0007] In order to achieve the above-mentioned object, the double-layer permeable pavement brick of the present invention comprises a concrete surface layer and a concrete bottom layer connected to each other;

[0008] The concrete surface layer is a permeable layer, the compressive strength grade of the concrete surface layer is C15-C30, and the water permeability coefficient is not less than 1 cm / s;

[0009] The concrete bottom layer is a load-bearing layer, the compressive strength grade of the concrete bottom layer is C60-C80, and a plurality of guide pipes penetrating the concrete bottom layer are arranged on the concrete bottom layer.

[0010] Optionally, the thickness of the concrete surface layer is smaller than the thickness of the concrete bottom layer.

[0011] Optionally, the thickness ratio of the concrete surface layer to the concrete bottom layer is 1:2 to 1:1.

[0012] Optionally, the guide pipe is a PVC pipe, the pipe diameter of the PVC pipe is 10 mm to 30 mm, and the wall thickness is greater than or equal to 1 mm.

[0013] Optionally, the concrete surface layer comprises the following raw materials in proportion by mass:

[0014] 100-200 parts of P.O52.5 cement or P.W52.5 cement, 700-800 parts of crushed stone with a particle size of 3mm-5mm, 5-10 parts of reinforcing agent, and 50-100 parts of water; among which, the reinforcing agent is a powdered admixture specially used for permeable concrete.

[0015] Optionally, the concrete surface layer further comprises color powder in a mass proportion of 1 to 10 parts, and the color powder is inorganic iron oxide color powder.

[0016] Optionally, the concrete base layer includes the following raw materials in the following mass proportions:

[0017] P.O52.5 cement 200-250 parts, silica fume 20-50 parts, crushed stone with a particle size of 5mm-10mm 300-400 parts, machine-made sand 250-350 parts, water 50-100 parts, water reducer 1-5 parts, defoamer 0.1-0.2 parts, synthetic fiber 3-8 parts;

[0018] Among them, the fineness modulus of the machine-made sand is 2.6 to 3.2, and the synthetic fiber is polyoxymethylene fiber (POM fiber) with a length of 10 mm to 14 mm.

[0019] Furthermore, the present invention also provides a method for preparing a double-layer permeable pavement brick, which comprises:

[0020] S1, preparing a concrete surface layer, mixing cement, crushed stone and reinforcing agent evenly to form a first dry mix;

[0021] Add water to the first dry mix and stir evenly for 3 to 5 minutes to form a first mixture;

[0022] S2, placing the first mixture in a mold and vibrating and pressing it to form the concrete surface layer;

[0023] S3, arranging a plurality of flow guide pipes in an array on the back side of the concrete surface layer that has been vibrated and pressed but not demolded;

[0024] S4, preparing a concrete base layer, mixing cement, silica fume, crushed stone, machine-made sand and synthetic fiber evenly to form a second dry mix;

[0025] The water reducing agent, the defoaming agent and the water are mixed evenly, and then added to the second dry mixed material and stirred evenly for 5 to 8 minutes to form a second mixed material;

[0026] S5. Before the concrete surface layer initially sets, pour the second mixture on the back of the concrete surface layer, cover with a film to retain moisture and allow to naturally cure for 24 hours before removing the formwork.

[0027] Optionally, in step S2, the vibration frequency is 50 Hz, the pressure is greater than or equal to 5 MPa, and the vibration pressure time is greater than or equal to 1 min.

[0028] Optionally, after step S5, the following steps are further included:

[0029] S6. Moisturizing and curing for at least 7 days, wherein the curing temperature is 20±2°C and the humidity is greater than or equal to 95%; after the curing is completed, the excessively long guide tube is removed to obtain a double-layer permeable pavement brick.

[0030] (III) Beneficial effects

[0031] The concrete surface layer is a permeable concrete layer, which can be made into a colored permeable concrete layer as needed, taking into account decoration; the concrete bottom layer is high-performance concrete, which is the main load-bearing structural layer, which improves the strength and bearing capacity of the double-layer permeable pavement bricks and avoids the collapse and cracking of the corners of the double-layer permeable pavement bricks. When it rains, rainwater can not only flow to the drainage ditch on the side of the road through the pavement structure on the concrete surface layer, but also infiltrate to the concrete bottom layer through the permeability of the concrete surface layer and then be discharged through multiple diversion pipes, which accelerates the diversion and infiltration of road surface water. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the double-layer permeable pavement brick of the present invention;

[0033] Figure 2 The present invention is a flow chart of the method for preparing the double-layer permeable pavement brick.

[0034] [Description of Reference Numerals]

[0035] 1: Concrete surface layer; 2: Concrete base layer; 3: Diversion pipe. DETAILED DESCRIPTION

[0036] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below in conjunction with the accompanying drawings through specific embodiments. Figure 1 The orientation is used as a reference.

[0037] Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0038] like Figure 1 As shown, the present invention provides a double-layer permeable pavement brick, which includes a concrete surface layer 1 and a concrete bottom layer 2, wherein the concrete surface layer 1 serves as the urban surface, the concrete bottom layer 2 is connected to the back of the concrete surface layer 1, the concrete surface layer 1 is a permeable layer, and the concrete bottom layer 2 is a load-bearing layer.

[0039] Among them, the concrete surface layer 1 is a permeable concrete layer, which can be made into a colored permeable concrete layer as needed, taking into account decoration; the concrete bottom layer 2 is a high-performance concrete, which is the main load-bearing structural layer, which improves the strength and bearing capacity of the double-layer permeable pavement bricks and avoids the collapse and cracking of the corners of the double-layer permeable pavement bricks. Specifically, the compressive strength grade of the concrete surface layer 1 is C15-C30, and the compressive strength grade is preferably C30 (concrete with a strength grade of C30 means 30MPa≤fcu, k≤35MPa), and the permeability coefficient is not less than 1cm / s. The compressive strength grade of the concrete bottom layer 2 is C60-C80, and the compressive strength grade is preferably C80. A plurality of diversion pipes 3 that penetrate the concrete bottom layer 2 are arranged on the concrete bottom layer 2. The diversion pipes 3 connect the soil and the back of the concrete surface layer 1. The diversion pipes 3 can divert the seepage water of the concrete surface layer 1 downward to the soil on the ground. When it rains, rainwater can not only flow to the drainage ditch on the road side through the pavement structure on the concrete surface layer 1, but also infiltrate into the concrete bottom layer 2 through the permeability of the concrete surface layer 1 and then be discharged through multiple diversion pipes 3, which accelerates the diversion and infiltration of surface water on the road. Higher permeability is conducive to improving the infiltration and drainage capacity of the urban surface and is conducive to the construction of a "sponge city"; based on the high strength and bearing capacity of the double-layer permeable bricks, the structural thickness of the permeable pavement can be effectively reduced, and the pavement structure composition can be simplified, thereby achieving the purpose of reducing costs and increasing efficiency.

[0040] Furthermore, if Figure 1 As shown, the thickness of the concrete surface layer 1 is less than the thickness of the concrete bottom layer 2, which improves the water permeability of the concrete surface layer 1 while improving the overall strength and load-bearing capacity of the double-layer permeable pavement brick. Specifically, the thickness ratio of the concrete surface layer 1 to the concrete bottom layer 2 is 1:2 to 1:1, preferably 1:1.5. The flow guide pipe 3 adopts a PVC pipe, and the diameter of the PVC pipe is 10mm to 30mm, preferably 20cm. The thickness of the pipe wall is greater than or equal to 1mm, preferably 1mm, to improve the strength of the pipe wall.

[0041] In a preferred embodiment, the concrete surface layer 1 comprises the following raw materials in proportion by mass:

[0042] 100-200 parts of P.O52.5 cement or P.W52.5 cement, 700-800 parts of crushed stone with a particle size of 3mm-5mm, 5-10 parts of reinforcing agent, and 50-100 parts of water; among which, the reinforcing agent is a powdered admixture specially used for permeable concrete, and the main components of the reinforcing agent include inorganic active fine powder and organic concrete admixture.

[0043] In addition, for colored pavement bricks, the concrete surface layer 1 also includes color powder in a mass ratio of 1 to 10 parts, and the color powder is inorganic iron oxide color powder.

[0044] In a preferred embodiment, the concrete base layer 2 comprises the following raw materials in the following mass proportions:

[0045] PO52.5 cement 200-250 parts, silica fume 20-50 parts, crushed stone with a particle size of 5mm-10mm 300-400 parts, machine-made sand 250-350 parts, water 50-100 parts, water reducer 1-5 parts, defoamer 0.1-0.2 parts, synthetic fiber 3-8 parts. Among them, the fineness modulus of machine-made sand is 2.6-3.2, and the synthetic fiber is 10mm-14mm long POM fiber (POM, Polyoxymethylene or Polyformaldehyde, polyoxymethylene fiber).

[0046] like Figure 2 As shown, the present invention also provides a method for preparing a double-layer permeable pavement brick, and the double-layer permeable pavement brick is prepared by using the above-mentioned material. The preparation method comprises:

[0047] Step 1: prepare a concrete surface layer 1, put cement, crushed stone and reinforcing agent into a mixer and mix them evenly to form a first dry mix; then add water to the first dry mix in the mixer and mix them together for 3 to 5 minutes, and mix them evenly to form a first mixture;

[0048] Step 2: placing the first mixture in a mold, and using equipment to vibrate and press it to form a concrete surface layer 1; wherein the mold is a mold for double-layer permeable pavement bricks, and the concrete surface layer 1 only occupies part of the mold space, and the remaining space is used to pour the concrete bottom layer 2;

[0049] Step 3: a plurality of guide tubes 3 are arranged in an array on the back side of the vibration-pressed and un-demolded concrete surface layer 1, wherein the length of the guide tube 3 exceeds the thickness of the concrete bottom layer 2, the first end of the guide tube 3 abuts against the back side of the concrete surface layer 1, and the second end of the guide tube 3 is fixed by a bracket;

[0050] Step 4: prepare a concrete base layer 2, put cement, silica fume, crushed stone, machine-made sand and synthetic fiber into another mixer and mix them evenly to form a second dry mix; after mixing the water reducer, defoamer and water evenly, put them into the mixer and mix them evenly with the second dry mix for 5 to 8 minutes to form a second mixture;

[0051] Step 5: Pour the stirred second mixture on the back of the concrete surface layer 1 before the initial setting of the concrete surface layer 1. The concrete material is in a self-leveling state and can be directly poured into shape without vibration. After pouring, cover the film to keep it moist and naturally cure for 24 hours before removing the mold.

[0052] Furthermore, in step 2, the vibration frequency of the first mixture during vibration pressing in the mold is preferably 50 Hz, the pressure is greater than or equal to 5 MPa, and the vibration pressing time is greater than or equal to 1 min.

[0053] The step 5 also includes the step 6, which is to maintain moisture for at least 7 days after demolding, wherein the curing temperature is 20±2° C. and the humidity is greater than or equal to 95%; after the curing is completed, the excessively long guide pipe 3 is cut off to obtain a double-layer permeable pavement brick.

[0054] The order of step 4 and step 3 can be exchanged, as long as the back of the concrete surface layer 1 is installed with a guide pipe 3 before pouring the concrete bottom layer 2.

[0055] During the preparation process, a concrete surface layer 1 is prepared first, and before the concrete surface layer 1 initially sets, the stirred second mixture is poured on the back of the concrete surface layer 1 to form a concrete base layer 2, thereby avoiding the situation in which effective bonding between the two layers cannot be achieved due to pouring the concrete base layer 2 first and then pouring the concrete surface layer 1. The preparation method effectively improves the stability and durability of the double-layer permeable pavement decorative bricks.

[0056] In one embodiment, the size of the double-layer permeable pavement decorative brick is 600mm*300mm*50mm, the 20mm thick concrete surface layer 1 uses beige permeable concrete, which also serves as a decorative layer; the 30mm thick concrete bottom layer 2 uses self-leveling high-performance concrete with a strength grade of C80. The beige permeable concrete is composed of the following raw materials by mass percentage: 165 parts of P.W52.5 cement, 755 parts of crushed stone with a particle size of 3-5mm, 6.5 parts of reinforcing agent, 70 parts of water, and 3.5 parts of color powder; the C80 self-leveling high-performance concrete is composed of the following raw materials by mass percentage: 235 parts of P.O52.5 cement, 21 parts of silica fume, 370 parts of 5-10mm crushed stone, 300 parts of machine-made sand, 70 parts of water, 2.2 parts of water reducer, 0.2 parts of defoamer, and 1.6 parts of synthetic fiber.

[0057] Preparation process: First, prepare a permeable concrete surface layer 1, put cement, crushed stone and reinforcing agent into a mixer and mix them evenly, then put water into the mixer and mix them together for 3 minutes, then put the mixture into a mold and vibrate and press for 1 minute to form it, with the vibration frequency set to 50Hz and the pressure set to 5MPa; after the pressing is completed, PVC pipes with a length of 35mm, an inner diameter of 20mm and a wall thickness of 1mm are fixed in a plum blossom shape on the back of the permeable concrete surface layer 1, with a horizontal spacing of 50mm and a spacing of 40mm between adjacent horizontal rows. Use a fixing tool to fix the PVC pipe on the molded the back of the surface layer; then prepare a high-performance concrete base layer 2, put cement, silica fume, crushed stone, machine-made sand and synthetic fiber into a mixer and mix them evenly, then mix the water reducer and defoamer with water evenly and put them into the mixer and stir them together for 5 minutes; pour the stirred high-performance concrete onto the permeable concrete surface layer 1 and cast it into shape. After the casting is completed, cover the film to keep it moist and maintain it naturally. After 24 hours, remove the mold and continue to maintain it moisturizing (the curing temperature is 20±2℃ and the humidity is not less than 95%) for 7 days. After the curing is completed, cut off the excessively long PVC pipe to obtain a double-layer beige permeable pavement decorative brick.

[0058] The concrete surface layer 1 serves as the urban surface, and the concrete bottom layer 2 is connected to the back of the concrete surface layer 1. The concrete surface layer 1 is a permeable layer, and the concrete bottom layer 2 is a load-bearing layer. Among them, the concrete surface layer 1 is an ordinary permeable concrete layer, which can be made into a colored permeable concrete layer as needed, taking into account decoration; the concrete bottom layer 2 is a high-performance concrete, which is the main load-bearing structural layer, which improves the strength and bearing capacity of the double-layer permeable pavement bricks and avoids the collapse and cracking of the corners of the double-layer permeable pavement bricks. When it rains, rainwater can not only flow to the drainage ditch on the side of the road through the pavement structure on the concrete surface layer 1, but also infiltrate into the concrete bottom layer 2 through the permeability of the concrete surface layer 1 and then be discharged through multiple diversion pipes 3, which accelerates the diversion and infiltration of surface water on the road.

[0059] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0060] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] In the present invention, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.

[0062] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0063] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A double-layer permeable pavement brick, characterized in that: The double-layer permeable pavement brick comprises a concrete surface layer and a concrete bottom layer connected to each other; The concrete surface layer is a permeable layer, the compressive strength grade of the concrete surface layer is C15-C30, and the water permeability coefficient is not less than 1 cm / s; The concrete bottom layer is a load-bearing layer, the compressive strength grade of the concrete bottom layer is C60-C80, and a plurality of guide pipes penetrating the concrete bottom layer are arranged on the concrete bottom layer.

2. The double-layer permeable pavement brick according to claim 1, characterized in that: The thickness of the concrete surface layer is smaller than the thickness of the concrete bottom layer.

3. The double-layer permeable pavement brick according to claim 2, characterized in that: The thickness ratio of the concrete surface layer to the concrete bottom layer is 1:2 to 1:

1.

4. The double-layer permeable pavement brick according to claim 1, characterized in that: The guide pipe is a PVC pipe with a pipe diameter of 10 mm to 30 mm and a wall thickness of greater than or equal to 1 mm.

5. The double-layer permeable pavement brick according to claim 1, characterized in that: The concrete surface layer comprises the following raw materials in proportion by mass: 100-200 parts of P.O52.5 cement or P.W52.5 cement, 700-800 parts of crushed stone with a particle size of 3mm-5mm, 5-10 parts of reinforcing agent, and 50-100 parts of water; among which, the reinforcing agent is a powdered admixture specially used for permeable concrete.

6. The double-layer permeable pavement brick according to claim 5, characterized in that: The concrete surface layer also includes color powder in a mass proportion of 1 to 10 parts, and the color powder is inorganic iron oxide color powder.

7. The double-layer permeable pavement brick according to claim 5, characterized in that: The concrete base layer comprises the following raw materials in proportion by mass: P.O52.5 cement 200-250 parts, silica fume 20-50 parts, crushed stone with a particle size of 5mm-10mm 300-400 parts, machine-made sand 250-350 parts, water 50-100 parts, water reducer 1-5 parts, defoamer 0.1-0.2 parts, synthetic fiber 3-8 parts; Among them, the fineness modulus of the machine-made sand is 2.6 to 3.2, and the synthetic fiber is polyoxymethylene fiber (POM fiber) with a length of 10 mm to 14 mm.

8. A method for preparing a double-layer permeable pavement brick, characterized in that: The preparation method comprises: S1, preparing a concrete surface layer, mixing cement, crushed stone and reinforcing agent evenly to form a first dry mix; Add water to the first dry mix and stir evenly for 3 to 5 minutes to form a first mixture; S2, placing the first mixture in a mold and vibrating and pressing it to form the concrete surface layer; S3, arranging a plurality of guide pipes in an array on the back side of the concrete surface layer that has been vibrated and pressed but not demolded; S4, preparing a concrete base layer, mixing cement, silica fume, crushed stone, machine-made sand and synthetic fiber evenly to form a second dry mix; The water reducing agent, the defoaming agent and the water are mixed evenly, and then added to the second dry mixed material and stirred evenly for 5 to 8 minutes to form a second mixed material; S5. Before the concrete surface layer initially sets, pour the second mixture on the back of the concrete surface layer, cover with a film to retain moisture and allow to naturally cure for 24 hours before removing the formwork.

9. The method for preparing the double-layer permeable pavement brick according to claim 8, characterized in that: In step S2, the vibration frequency is 50 Hz, the pressure is greater than or equal to 5 MPa, and the vibration pressure time is greater than or equal to 1 min.

10. The method for preparing the double-layer permeable pavement brick according to claim 8, characterized in that: After step S5, the following steps are also included: S6. Moisturizing and curing for at least 7 days, wherein the curing temperature is 20±2°C and the humidity is greater than or equal to 95%; after the curing is completed, the excessively long guide tube is removed to obtain a double-layer permeable pavement brick.

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