Vegetation ecological concrete and preparation method thereof

Abstract

The invention discloses vegetation ecological concrete and a preparation method thereof, and belongs to the technical field of ecological concrete. The vegetation ecological concrete is prepared from the following raw materials in parts by weight: 200 to 300 parts of cement, 600 to 780 parts of sand, 1600 to 1800 parts of soil particles, 400 to 500 parts of sawdust, 180 to 230 parts of water, 320 to 360 parts of polyacrylamide aqueous solution, 4 to 10 parts of water reducing agent, 60 to 80 parts of organic fertilizer and fly ash. The soil blocks treated and pressed by the polyacrylamide aqueous solution are used for replacing coarse aggregate in the concrete, so that the consumption of cement and other materials is reduced, the water permeability and water retention of the vegetation ecological concrete are improved, and a growth environment can be provided for vegetation; the vegetation ecological concrete can be used for projects such as ecological slope protection, urban green infrastructure construction and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ecological concrete, in particular to a plant ecological concrete and a preparation method thereof. BACKGROUND

[0002] Ecological concrete is a new environmental protection technology that takes into account both structural performance and ecological function. Its design concept breaks through the limitations of traditional concrete, which only focuses on mechanical properties, aiming to reduce the load on the environment while achieving coordinated symbiosis with the ecological system. Ecological concrete has air permeability, water permeability or pore structure, can provide living space for microorganisms, plants and animals, and can meet certain strength and durability requirements, and can adapt to different engineering scenarios. Ecological concrete mainly includes water permeable ecological concrete, vegetation type ecological concrete and water environment repair type ecological concrete. Water permeable ecological concrete mainly realizes rainwater infiltration through continuous pore structure, relieves urban waterlogging, replenishes groundwater, and is commonly used in sidewalks, parking lots, etc. Vegetation type ecological concrete can fill soil and nutrient medium in the pores for plant growth, and is commonly used for slope greening and roof gardens, combining soil fixation and landscape functions. Water environment repair type ecological concrete adds functional materials (such as activated carbon, microbial carriers) to adsorb pollutants or promote water purification, and is applied to river and lake management.

[0003] The patent document with application number 202510254449.9 discloses a preparation method of ecological concrete. The ecological concrete uses gravel as coarse aggregate. Due to the large amount of coarse aggregate, the production cost increases. In addition, due to the large proportion of gravel, the living space of vegetation is greatly reduced. Moreover, the production process is complicated, which cannot meet the needs of engineering development. The porosity, compressive strength, air permeability and water retention of related plant type porous concrete are difficult to achieve effective balance. These properties affect each other. Optimizing one property may often lead to deterioration of other properties. The water storage capacity of related ecological concrete is poor during preparation, which makes it difficult to supplement water for vegetation. Water loss is rapid. Due to the need to consider air permeability, it is difficult to ensure the basic strength of the ecological concrete. Therefore, it is necessary to develop a plant ecological concrete that takes into account the porosity, compressive strength, air permeability and water retention. SUMMARY

[0004] To solve the problems that related technologies cannot well balance the porosity, compressive strength, air permeability and water retention of plant type ecological concrete, and the production method is complicated, the purpose of the present application is to provide a plant ecological concrete and a preparation method thereof. The plant ecological concrete of the present application uses specially treated soil blocks instead of coarse aggregate in concrete. The prepared ecological concrete has good air permeability, excellent water retention and high compressive strength, and the preparation method is simple to operate.

[0005] The plant ecological concrete comprises the following raw materials in parts by weight: cement 200-300 parts, sand 600-780 parts, soil particles 1700 parts, wood chips 400-500 parts, water 180-230 parts, polyacrylamide aqueous solution 320-360 parts, polycarboxylate superplasticizer 4-10 parts, organic fertilizer 60-80 parts, and fly ash.

[0006] Preferably, the weight of the fly ash is 30%-50% of the weight of the cement.

[0007] Preferably, the mass concentration of the polyacrylamide aqueous solution is 0.1%-0.5%, and a too high concentration will cause excessive soil adhesion and affect the air permeability.

[0008] Preferably, the sand is one or more of quartz sand, river sand, or machine-made sand, and the particle size of the sand is 0.15-0.6 mm.

[0009] Preferably, the soil particles have a diameter of 1-3 mm.

[0010] Preferably, the wood chips have a size of ≦1 cm. 3 .

[0011] Preferably, the pressing condition is pressing under a pressure of 0.5-5 MPa, and the pressure can be adjusted according to the size of the wood chips. If the wood chip particles are large, the pressure can be appropriately increased.

[0012] The preparation method of the plant ecological concrete comprises the following steps: (1) Spraying the prepared polyacrylamide aqueous solution on the surface of the soil particles, and fully stirring to obtain treated soil particles; the water content of the soil particles is about 20%, and the polyacrylamide aqueous solution can increase the coagulation, water retention, and fertilizer retention of the soil particles.

[0013] (2) Mixing the treated soil particles, wood chips, and organic fertilizer uniformly to obtain a mixed soil body; the addition of wood chips ensures that the ecological concrete soil body is loose and porous, and provides nutrients for vegetation growth; the added organic fertilizer should be composted in advance to avoid burning the roots of the vegetation by uncomposted organic fertilizer.

[0014] (3) Pressing the mixed soil body to obtain a soil block; (4) Cleaning the site to be constructed, then erecting a formwork in the working area, and orderly stacking the pressed soil blocks.

[0015] (5) mixing and stirring cement, fly ash, sand, water and water reducing agent to obtain self-leveling cement mortar, pouring the self-leveling cement mortar along the gap reserved when the concrete block is stacked, the pouring plane is not higher than the upper surface of the soil block, and is close to the upper surface of the soil block, so that the soil block is not covered by the cement mortar, and ecological concrete maintenance is performed after pouring.

[0016] The soil block in step (3) is an octagonal prism, a dodecahedron, a tetrakaidecahedron or a hexadecahedron. According to actual needs, the mold in the pressing process is correspondingly selected as an octagonal prism, a dodecahedron, a tetrakaidecahedron or a hexadecahedron, and various sizes with a side length of 2-8 cm are preferred, and the corresponding size can be selected according to the area to be constructed.

[0017] The cement mortar has a slump of 250-280 mm and a slump flow of 650-800 mm.

[0018] Another object of the application is to apply the prepared plant ecological concrete to ecological restoration and environmental protection.

[0019] The mechanism of the application is that the application breaks the simple mixing mode of traditional ecological concrete, realizes the synergistic improvement of soil structure stability, vegetation adaptability and concrete mechanical properties through the multi-stage synergistic effect of polyacrylamide treatment, organic additive composite modification and staggered stacking design, the long molecular chain of polyacrylamide absorbs soil particles through polar groups to form a micro-scale "adsorption-bridging" network (chemical bond effect), the incorporation of sawdust and organic fertilizer constructs loose pores in the macro scale and provides nutrients for vegetation, and the two realize the dual regulation of chemical cementation and physical pores, thereby enhancing the cohesion of the soil body and maintaining the air and water permeability, and providing a gradient pore structure for subsequent concrete penetration and plant root expansion; the three-dimensional connected channels formed by the regular soil blocks and the staggered stacking increase the contact area of the concrete, save the amount of concrete, are beneficial to the growth of the vegetation roots, and the developed roots improve the integrity and strength of the structure.

[0020] The application has the following beneficial effects: The soil block treated by the polyacrylamide aqueous solution is used to replace coarse aggregate, thereby reducing the exploitation of stone and effectively protecting natural resources; the sawdust can maintain the looseness of the soil, and the pre-mixed sawdust particles and organic fertilizer in the soil block create an excellent environment for the growth of vegetation; the staggered stacking design of the regular soil blocks makes the spatial distribution of the structure more uniform, provides sufficient space for the expansion of the plant roots, greatly improves the strength, integrity and durability of the concrete, and optimizes the load bearing capacity; the water permeability and environmental protection are obviously improved compared with traditional ecological concrete, and the construction efficiency is higher, which is conducive to the harmonious development of engineering construction and ecological environment. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a flowchart of the preparation of ecological concrete according to the present application.

[0022] Figure 2 is a schematic diagram of a regular octagonal prism pressing mold according to the present application.

[0023] Figure 3 is a schematic diagram of a regular octagonal prism soil block according to the present application.

[0024] Figure 4 is a schematic diagram of a regular octagonal prism soil block according to the present application.

[0025] Figure 5 is a schematic diagram of a regular dodecahedron soil block according to the present application.

[0026] Figure 6 is a schematic diagram of a regular dodecahedron soil block according to the present application. DETAILED DESCRIPTION

[0027] In the following examples, the fly ash is Grade I fly ash; the soil particles are ordinary black soil, with a soil particle diameter of 1-3 mm; the cement is P.O42.5 ordinary portland cement; the sand is refined quartz sand; the wood chips are natural pine wood chips, with a particle volume of less than 1 cm 3 ; the polyacrylamide is a type with easy degradation and low residue; the water is laboratory tap water; the water reducing agent is a polycarboxylic acid type high performance water reducing agent; and the pressing mold is a regular octagonal prism mold with a side length of 4 cm.

[0028] Example 1 The steps for preparing the ecological concrete in this example are as follows: (1) 1700 parts of soil were placed in a mixing pot, and 340 parts of a 0.1% polyacrylamide aqueous solution was uniformly sprayed on the surface of the soil to make the soil have a water content of about 20%.

[0029] (2) 400 parts of wood chips, 80 parts of organic fertilizer, and the soil particles of step (1) were uniformly mixed to obtain a mixed soil body, which was placed in a cool place for standby.

[0030] (3) The mixed soil body was placed in a regular octagonal prism mold with a side length of 4 cm, and the soil block was pressed with a pressure of 0.5 MPa. The pressed soil block was placed in a standard curing room for curing and standby.

[0031] (4) The site to be constructed was cleaned, and a formwork was erected. The prepared soil blocks were stacked in a way that the edges of each layer were connected and the upper and lower layers were stacked in a staggered manner until the height of the stack reached the same height as the construction formwork.

[0032] (5) Put 200 parts of ordinary Portland cement, 100 parts of I-grade fly ash and 600 parts of quartz sand into a stirring pot, stir for 2 min to mix evenly, then add 180 parts of water, stir for 3 min, add 4 parts of polycarboxylic acid high-performance water reducing agent during stirring, and stir for 1 min again to obtain self-leveling cement mortar. Pour the self-leveling cement mortar into the pouring holes left by the soil blocks during stacking, and the pouring plane should not exceed the upper surface of the soil blocks and be close to the upper surface of the soil blocks. Each pouring hole is filled until the pouring is completed. Then, the standard curing room with an environmental temperature of 20°C and a humidity of 95% is used for curing, and the mold is removed after 7 days of curing.

[0033] Example 2 The steps for preparing the ecological concrete in this example are as follows: (1) Take 1600 parts of soil and place it in a stirring pot. Sprinkle 320 parts of a polyacrylamide aqueous solution with a mass concentration of 0.3% evenly on the surface of the soil to make the water content of the soil about 20%.

[0034] (2) Mix 450 parts of wood chips and 70 parts of organic fertilizer with the soil particles of step (1) to obtain a mixed soil body, and place it in a cool place for standby.

[0035] (3) Put the mixed soil body into a regular octagon prism mold with a side length of 4 cm, and press the soil blocks with a pressure of 2.5 MPa. The pressed soil blocks are placed in a standard curing room for curing and standby.

[0036] (4) Clean the site to be constructed and set up the formwork. The prepared soil blocks are stacked in a way that the edges of each layer are connected and the upper and lower layers are stacked in a staggered manner until the height of the stack reaches the same height as the construction formwork.

[0037] (5) Put 200 parts of ordinary Portland cement, 100 parts of I-grade fly ash and 600 parts of quartz sand into a stirring pot, stir for 2 min to mix evenly, then add 180 parts of water, stir for 3 min, add 4 parts of polycarboxylic acid high-performance water reducing agent during stirring, and stir for 1 min again to obtain self-leveling cement mortar. Pour the self-leveling cement mortar into the pouring holes left by the soil blocks during stacking, and the pouring plane should not exceed the upper surface of the soil blocks and be close to the upper surface of the soil blocks. Each pouring hole is filled until the pouring is completed. Then, the standard curing room with an environmental temperature of 20°C and a humidity of 95% is used for curing, and the mold is removed after 7 days of curing.

[0038] Example 3 The steps for preparing the ecological concrete in this example are as follows: (1) Take 1800 parts of soil and place it in a stirring pot. Sprinkle 360 parts of a polyacrylamide aqueous solution with a mass concentration of 0.5% evenly on the surface of the soil to make the water content of the soil about 20%.

[0039] (2) 500 parts of wood chips and 60 parts of organic fertilizer and soil particles of step (1) are mixed uniformly to obtain a mixed soil body, which is placed in a cool place for standby.

[0040] (3) The mixed soil body is placed into a regular octagonal prism mold with a side length of 4 cm, and the soil block is pressed with a pressure of 5 MPa, and the pressed soil block is placed in a standard curing chamber for standby.

[0041] (4) The site to be constructed is cleaned, and a formwork is erected, and the prepared soil block is stacked in a way that the edges of each layer are connected and the upper and lower two layers are stacked in a staggered manner until the same height as the construction formwork.

[0042] (5) 300 parts of ordinary Portland cement, 90 parts of I-grade fly ash and 780 parts of quartz sand are placed in a stirring pot, stirred for 2 min, then 230 parts of water is added, stirred for 3 min, 10 parts of polycarboxylic acid high-performance water reducing agent is added during stirring, and stirred for 1 min to obtain a self-leveling cement mortar. The self-leveling cement mortar is poured into the pouring hole left by the soil block stacking, the pouring plane is not more than the upper surface of the soil block, and the pouring plane is close to the upper surface of the soil block. Each pouring hole is poured until it is full, and then it is cured in a standard curing chamber with an environmental temperature of 20°C and a humidity of 95% for 7 days.

[0043] Comparative Example 1 The remaining steps of this comparative example are the same as those of Example 3, except that the soil particles are not treated with a polyacrylamide aqueous solution.

[0044] Comparative Example 2 The remaining steps of this comparative example are the same as those of Example 3, except that the soil body is stacked in a way that the upper and lower layers are aligned and closely connected, without being stacked in a staggered manner.

[0045] Comparative Example 3 The remaining steps of this comparative example are the same as those of Example 3, except that no wood chip particles are added when stirring the soil.

[0046] The concrete prepared in Examples 1-3 and Comparative Examples 1-3 is tested for structural connectivity and strength. The structural connectivity is determined by measuring the water permeation time of the structure at the same height of 40 cm and the root length of the vegetation under the same conditions and time (60-day growth period). The structural strength test is performed by cutting the same size (70.7 cm cube) of the test piece at the same position after curing for the same time, and the compressive strength test is performed. The experimental results are shown in Table 1.

[0047] Table 1 As shown in Table 1, the polyacrylamide aqueous solution can agglomerate the dispersed soil particles into large aggregates through adsorption and bridging effect, improve water retention and fertilizer retention, and be beneficial to vegetation growth; the upper and lower staggered stacking mode can make the gaps between the soil layers more staggered for filling of the cement mortar, make the structure form a more complete whole, and improve the compressive strength; the addition of wood particle and organic fertilizer in the soil can improve the air permeability of the structure, and can provide growth space and nutrient substances for vegetation, and be beneficial to the water permeability of the ecological concrete.

[0048] The above has described various embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, practical application or improvement of the technology in the market, or to enable other ordinary skilled in the art to understand the embodiments disclosed herein.

Claims

1. A vegetative ecological concrete, characterized in that: The vegetation ecological concrete comprises the following raw materials in parts by weight: 200-300 parts of cement, 600-780 parts of sand, 1600-1800 parts of soil particles, 400-500 parts of sawdust, 180-230 parts of water, 320-360 parts of polyacrylamide aqueous solution, 4-10 parts of water reducing agent, 60-80 parts of organic fertilizer and fly ash.

2. The vegetation ecological concrete according to claim 1, characterized in that: The mass concentration of the polyacrylamide aqueous solution is 0.1%-0.5%; the weight of the fly ash is 30%-50% of the cement.

3. The vegetation ecological concrete according to claim 1, characterized in that: The sand is one or more of quartz sand, river sand or machine-made sand, and the particle size of the sand is 0.15-0.6 mm.

4. The method for preparing the vegetative ecological concrete according to claim 1, characterized in that: The specific steps include: (1) Spraying the polyacrylamide aqueous solution on the surface of soil particles and stirring evenly to obtain treated soil particles; (2) uniformly mixing the treated soil particles, sawdust, and organic fertilizer to obtain a mixed soil mass; (3) Pressing the mixed soil into a shape to obtain soil blocks; (4) Stack the pressed soil blocks in an orderly manner; (5) Cement, fly ash, quartz sand, water and water reducing agent are mixed and stirred to obtain self-leveling cement mortar, and the stacked concrete blocks are poured with the self-leveling cement mortar, and then cured after pouring.

5. The method for preparing the vegetation ecological concrete according to claim 5, characterized in that: The diameter of the soil particles in step (1) is 1-3 mm.

6. The method for preparing the vegetation ecological concrete according to claim 5, characterized in that: The sawdust size mentioned in step (2) is ≤ 1cm 3 .

7. The method for preparing the vegetative ecological concrete according to claim 5, characterized in that: The pressing conditions in step (3) are: pressing at a pressure of 0.5-5 MPa.

8. The method for preparing the vegetation ecological concrete according to claim 5, characterized in that: The soil block in step (3) is a regular octagonal prism, a regular dodecahedron, a regular tetradecahedron or a regular hexadecahedron.

9. The method for preparing the vegetation ecological concrete according to claim 5, characterized in that: The orderly stacking in step (4) is as follows: when stacking, each layer of soil blocks is closely connected edge to edge, and two adjacent layers of soil blocks are stacked in staggered layers, so that there is a gap between each layer for self-leveling cement mortar to be filled with its own weight.

10. Use of the vegetative ecological concrete prepared by the method according to any one of claims 1 to 9 in ecological slope protection.

Images