Biochar modified recycled concrete substrate for a planted roof construction and method of making

Abstract

The present application relates to a kind of planting roof structure of biochar modified recycled concrete substrate and its preparation method, planting roof structure includes vegetation layer, biochar modified small particle size recycled concrete aggregate layer, coarse particle size recycled concrete aggregate layer, gravel recycled concrete aggregate layer, non-woven filter layer, drainage plate and root penetration resistant waterproof layer from top to bottom successively arranged;Wherein, biochar modified small particle size recycled concrete aggregate layer is composed of biochar and small particle size recycled concrete aggregate.It can improve the phosphorus, potassium content of substrate, which is beneficial to promote plant growth, biochar has good adsorption function, and can improve leachate water quality.Avoid the problem of poor drainage of roof.Crude particle size recycled concrete aggregate substrate planting environment is alkaline, can inhibit plant root growth, avoid roof waterproof layer to be subjected to plant root system intrusion damage, protect roof waterproof structure, prevent roof from leaking.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of roof greening, in particular to a planting roof structure of biochar modified recycled concrete substrate and a preparation method thereof. BACKGROUND

[0002] The conventional planting roof structure is arranged from top to bottom as a vegetation layer, a planting soil layer, a non-woven fabric filter layer, a water drainage / accumulation layer, a geotextile protective layer, and a root penetration resistant waterproof layer, wherein the root penetration resistant waterproof layer is usually protected by an asphalt-based root penetration resistant waterproof roll.

[0003] However, the construction process of the roll inevitably involves the problem of joint lap processing. The joint lap is a weak part of the root penetration resistant waterproof layer, which is easily invaded by plant roots. Once the roots grow further, they will penetrate the geotextile protective layer and damage the root penetration resistant waterproof layer, thereby causing a series of problems such as roof leakage and drainage system blockage.

[0004] In addition, the plant-growing concrete, also known as plant-compatible ecological concrete or vegetation concrete, is composed of porous concrete, water-retaining materials and nutrients, surface soil, and plants, and is generally prepared by on-site mixing and overall pouring. It only provides a place for plant roots and microorganisms to attach, mainly relies on plant roots to purify water, and does not have the function of filtering and purifying rainwater itself. Moreover, the porous concrete pores are often blocked due to cement hardening, resulting in poor drainage. SUMMARY

[0005] In view of the problems in the prior art, the present application aims to provide a planting roof structure of biochar modified recycled concrete substrate and a preparation method thereof, which can purify rainwater and prevent the root penetration resistant waterproof layer from being damaged by plant roots, thereby preventing roof leakage or poor drainage.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] The planting roof structure of biochar modified recycled concrete substrate comprises, from top to bottom, a vegetation layer, a biochar modified small particle size recycled concrete aggregate layer, a coarse particle size recycled concrete aggregate layer, a gravel recycled concrete aggregate layer, a non-woven fabric filter layer, a drainage board, and a root penetration resistant waterproof layer.

[0008] The biochar modified small particle size recycled concrete aggregate layer is composed of biochar and small particle size recycled concrete aggregate.

[0009] Further, in the biochar modified small particle size recycled concrete aggregate layer, the average particle size of the small particle size recycled concrete aggregate is 0.6 mm; the biochar is cow dung carbon, and the mixing mass ratio of the small particle size recycled concrete aggregate to the cow dung carbon is 9:1.

[0010] Further, the thickness of the biochar modified small particle size recycled concrete aggregate layer is 600mm.

[0011] Further, in the coarse particle size recycled concrete aggregate layer, the average particle size of the coarse particle size recycled concrete aggregate is 2.5mm.

[0012] Further, the thickness of the coarse particle size recycled concrete aggregate layer is 100mm.

[0013] Further, in the gravel recycled concrete aggregate layer, the average particle size of the recycled concrete aggregate is 5mm.

[0014] Further, a geotextile or polyester non-woven fabric protective layer is arranged between the coarse particle size recycled concrete aggregate layer and the gravel recycled concrete aggregate layer.

[0015] The preparation method of the biochar modified recycled concrete substrate planting roof structure comprises the following steps,

[0016] The vegetation layer, the biochar modified small particle size recycled concrete aggregate layer, the coarse particle size recycled concrete aggregate layer, the gravel recycled concrete aggregate layer, the non-woven fabric filter layer, the drainage plate and the root penetration resistant waterproof layer are arranged on the roof from top to bottom.

[0017] The biochar modified small particle size recycled concrete aggregate layer is composed of biochar and small particle size recycled concrete aggregate.

[0018] Further, a geotextile or polyester non-woven fabric protective layer is arranged between the coarse particle size recycled concrete aggregate layer and the gravel recycled concrete aggregate layer.

[0019] Further, the preparation method of the biochar modified small particle size recycled concrete aggregate layer is,

[0020] The waste concrete is crushed and sieved into an aggregate with an average particle size of 0.6mm, mixed with 10% mass ratio of cow dung carbon, and hammered and compacted by a compaction hammer every 50mm, to prepare a 600mm thick layer.

[0021] Overall, the present application has the following advantages:

[0022] The application improves the planting soil layer under the vegetation layer to a biochar modified small particle size recycled concrete aggregate layer, which can increase the phosphorus and potassium content of the substrate and is conducive to promoting plant growth. The biochar has good adsorption function, and together with the biodegradation in the planting substrate, the quality of the leachate can be improved, and the effect of purifying rainwater can be achieved. Compared with the vegetation concrete, the biochar modified concrete recycled aggregate of the application is not hardened by cement, and there is no phenomenon of pore blockage, which avoids the problem of poor drainage of the roof. The coarse particle size recycled concrete aggregate layer is used as a waterproof structure protection layer, and the coarse particle size recycled concrete aggregate substrate planting environment is alkaline, which can inhibit the growth of plant roots and avoid the destruction of the waterproof layer of the roof by plant roots, protect the waterproof structure of the roof, and prevent the roof from leaking, thereby providing a new method for protecting the waterproof layer of the traditional planting roof. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The structure schematic diagram of the embodiment of the application.

[0024] In the figure:

[0025] 1-vegetation layer, 2-biochar modified small particle size recycled concrete aggregate layer, 3-coarse particle size recycled concrete aggregate layer, 4-geotextile layer, 5-gravel recycled concrete aggregate layer, 6-non-woven fabric filter layer, 7-drainage board, 8-polyester non-woven fabric protection layer, 9-root penetration resistant waterproof layer, 10-cement mortar leveling layer, 11-sloping layer, 12-reinforced concrete roof panel. DETAILED DESCRIPTION

[0026] The traditional planting roof does not have the function of purifying rainwater, and the waterproof layer thereof is easily damaged by plant roots, which further causes a series of problems such as roof leakage and drainage system blockage. In terms of structure, the root resistance mechanism of the traditional modified bitumen root penetration resistant membrane is not reliable, and the copper-based root penetration resistant waterproof membrane has the problems of high cost and difficult construction.

[0027] The application uses biochar modified concrete recycled aggregate substrate to replace the soil layer of the traditional planting roof, which can provide a new use scenario for the utilization of construction waste and improve the resource utilization rate of construction waste. On the other hand, the new planting roof structure using biochar modified concrete recycled aggregate has the function of purifying rainwater.

[0028] The application will be further described in detail below.

[0029] As Figure 1As shown, the biochar modified recycled concrete substrate planting roof structure includes, from top to bottom, a vegetation layer 1, a biochar modified small particle size recycled concrete aggregate layer 2, a coarse particle size recycled concrete aggregate layer 3, a gravel recycled concrete aggregate layer 5, a non-woven fabric filter layer 6, a drainage board 7 and a root penetration resistant waterproof layer 9 arranged above the roof;

[0030] The biochar modified small particle size recycled concrete aggregate layer 2 is composed of biochar and small particle size recycled concrete aggregate.

[0031] Compared with the traditional planting roof, the biochar modified small particle size recycled concrete aggregate layer 2 is used to replace the traditional planting soil layer in the present application. Since the biochar has good adsorption function and the recycled concrete aggregate can provide a suitable space environment for the growth of microorganisms, the present application can purify rainwater through physical adsorption and biological degradation. The experimental results show that the present application has obvious purification effect on copper, zinc, high ammonia nitrogen and low ammonia nitrogen, and the pollutant removal rate can reach more than 80%.

[0032] The recycled concrete aggregate is an environmentally friendly material, but it cannot provide nutrient elements for plant growth. The present application improves the recycled concrete aggregate by biochar. The experimental results show that the best type of biochar is cow dung carbon, and the optimal mass ratio of waste concrete recycled aggregate to cow dung carbon is 9:1. Biochar can increase the content of phosphorus and potassium in the substrate and provide nutrient ingredients for plants. The growth of experimental Miscanthus sinensis in the biochar modified small particle size recycled concrete aggregate substrate is good. After the small particle size recycled concrete aggregate with an average particle size of 0.6 mm is fully mixed with biochar, the layers are compacted by using a compactor. Compared with the vegetation concrete, the biochar modified small particle size recycled concrete aggregate of the present application is not hardened by cement, and there is no phenomenon of pore blockage, thereby avoiding the problem of poor drainage of the roof.

[0033] The coarse particle size recycled concrete aggregate layer 3 is used as a waterproof structure protection layer in the present application, and there is no problem of joint lap treatment, thereby avoiding the invasion of plant roots from the weak structure of the lap. The planting environment of the concrete recycled aggregate substrate is alkaline, which can inhibit the growth of plant roots and avoid the damage of the plant roots to the waterproof layer of the roof, thereby protecting the waterproof structure of the roof and preventing the roof from leaking.

[0034] Concrete materials are widely used in the construction industry, but a large amount of construction waste is also generated at the end of the construction life cycle. The waste concrete can cause damage to the environment. The present application uses biochar to transform the waste concrete into improved concrete recycled aggregate, studies the technical method of using the improved concrete recycled aggregate to replace natural soil for green roof, and provides theoretical and technical support for the recycling of construction waste in the sponge city, which is conducive to environmental protection.

[0035] The present embodiment also provides a preparation method of a planting roof structure of biochar modified recycled concrete substrate, as shown in the figure, comprising the following steps, Figure 1

[0036] A light aggregate concrete or foam concrete slope layer 11 is arranged on the reinforced concrete roof panel 12 of the roof;

[0037] A cement mortar leveling layer 10 is arranged on the slope layer 11;

[0038] A vegetation layer 1, a biochar modified small particle size recycled concrete aggregate layer 2, a coarse particle size recycled concrete aggregate layer 3, a geotextile or polyester non-woven fabric layer, a gravel recycled concrete aggregate layer 5, a non-woven fabric filter layer 6, a drainage board 7, a geotextile or polyester non-woven fabric and root penetration resistant waterproof layer 9 are sequentially arranged above the cement mortar leveling layer 10 from top to bottom.

[0039] Among them, the surface layer below the vegetation layer 1 is a 600mm thick biochar modified small particle size concrete recycled aggregate (BC-RCA). The waste concrete is crushed and sieved into aggregate with an average particle size of 0.6mm, and 10% mass ratio of cow dung carbon is fully mixed, and a compaction hammer is used for layering and hammering every 50mm.

[0040] The second layer is a 100mm thick coarse particle size waste concrete recycled aggregate with an average particle size of 2.5mm.

[0041] It can be explained that in order to filter the biochar particles and prevent the biochar from sinking, the present application has a geotextile layer 4 at the bottom of the 2.5mm waste concrete coarse particle size recycled aggregate layer.

[0042] The filter layer is a 300mm thick gravel concrete recycled aggregate with an average particle size of 5mm, which preliminarily filters the upper layer substrate. It should be particularly pointed out that the planting environment of the waste concrete recycled aggregate not modified by biochar is alkaline, which has an inhibitory effect on the growth of plant roots, can control the growth of plant roots, and protect the waterproof layer.

[0043] The non-woven fabric filter layer 6 further filters the upper layer substrate and prevents the substrate from entering the drainage layer.

[0044] In the present embodiment, the drainage board 7 adopts a concave-convex type drainage board (water storage board), which is used to improve the ventilation condition of the substrate, quickly drain excess water, effectively relieve instantaneous pressure, and store a small amount of water for the normal growth of plants.

[0045] The concave-convex type drainage board (water storage board) is provided below the geotextile layer 4 or polyester non-woven fabric protection layer 8.

[0046] The geotextile layer 4 and the root penetration resistant waterproof layer 9 control the growth of plant roots and prevent the plant roots from penetrating the waterproof layer, causing damage to the lower structure layer or blocking the drainage system. ​

[0047] By adopting the technical scheme, the content of phosphorus and potassium of the substrate can be increased by using the cow dung carbon with a mass ratio of 10%, and the growth of plants is promoted.

[0048] By adopting the technical scheme, the simulated rainwater can be purified by physical adsorption and biological degradation. According to experiments, as shown in Table 1, the removal rate of copper (Cu) ions in the simulated rainwater is 85.3%, the removal rate of zinc (Zn) ions is 81.3%, the removal rate of high ammonia nitrogen is 84.7%, and the removal rate of low ammonia nitrogen is 85.7%. The purification performance is good.

[0049] Table 1: Experimental data of simulated rainwater purification

[0050] Copper (mg / L) Zinc (mg / L) Low ammonia nitrogen (mg / L) High ammonia nitrogen (mg / L) Initial configuration solution concentration 0.13 0.92 8.96 14.39 Leachate concentration 0.02 0.17 1.30 2.17 Contaminant removal rate 85.3％ 81.3％ 85.7％ 84.7％

[0051] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, and are all included in the protection scope of the present application.

Claims

1. A green roof structure based on biochar-modified recycled concrete substrate, characterized in that: It includes, from top to bottom, a vegetation layer, a biochar-modified small-particle-size recycled concrete aggregate layer, a coarse-particle-size recycled concrete aggregate layer, a gravel recycled concrete aggregate layer, a non-woven filter layer, a drainage board, and a root-penetration-resistant waterproof layer. Among them, the biochar-modified small-particle-size recycled concrete aggregate layer is composed of biochar and small-particle-size recycled concrete aggregate. In the biochar-modified small-particle-size recycled concrete aggregate layer, the average particle size of the small-particle-size recycled concrete aggregate is 0.6 mm; the biochar is cow dung char, and the mass ratio of small-particle-size recycled concrete aggregate to cow dung char is 9:

1. The preparation method of biochar-modified small-particle-size recycled concrete aggregate layer is as follows: Waste concrete was crushed and sieved into aggregate with an average particle size of 0.6 mm. It was then thoroughly mixed with 10% cow dung charcoal by mass and compacted in 50 mm layers using a compaction hammer, resulting in a total thickness of 600 mm.

2. The green roof structure based on biochar-modified recycled concrete substrate according to claim 1, characterized in that: The thickness of the aggregate layer in biochar-modified small-particle-size recycled concrete is 600 mm.

3. The green roof structure based on biochar-modified recycled concrete substrate according to claim 1, characterized in that: In the coarse-grained recycled concrete aggregate layer, the average particle size of the coarse-grained recycled concrete aggregate is 2.5 mm.

4. The green roof structure based on biochar-modified recycled concrete substrate according to claim 1, characterized in that: The thickness of the coarse-grained recycled concrete aggregate layer is 100mm.

5. The green roof structure based on biochar-modified recycled concrete substrate according to claim 1, characterized in that: In the gravel recycled concrete aggregate layer, the average particle size of the recycled concrete aggregate is 5 mm.

6. The green roof structure based on biochar-modified recycled concrete substrate according to claim 1, characterized in that: A geotextile or polyester nonwoven fabric protective layer is provided between the coarse-grained recycled concrete aggregate layer and the gravel recycled concrete aggregate layer.

7. The method for preparing a green roof structure based on biochar-modified recycled concrete matrix as described in any one of claims 1-6, characterized in that: Includes the following steps, The following layers are arranged from top to bottom on the roof: a vegetation layer, a biochar-modified small-particle-size recycled concrete aggregate layer, a coarse-particle-size recycled concrete aggregate layer, a gravel recycled concrete aggregate layer, a non-woven filter layer, a drainage board, and a root-penetration resistant waterproof layer. The biochar-modified small-particle-size recycled concrete aggregate layer consists of biochar and small-particle-size recycled concrete aggregate.

8. The preparation method according to claim 7, characterized in that: A geotextile or polyester nonwoven fabric protective layer is installed between the coarse-grained recycled concrete aggregate layer and the gravel recycled concrete aggregate layer.

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