CN116621548B

CN116621548B - Low-alkali regenerated ecological concrete with high plant growth performance and construction method thereof

Info

Publication number: CN116621548B
Application number: CN202310920170.0A
Authority: CN
Inventors: 金珊珊; 徐增淼; 杨媛; 张扬; 李傲东; 季节; 刘鹏飞; 李响; 严雨苓; 李刘欢
Original assignee: Beijing University of Civil Engineering and Architecture
Current assignee: Beijing University of Civil Engineering and Architecture
Priority date: 2023-07-26
Filing date: 2023-07-26
Publication date: 2023-10-10
Anticipated expiration: 2043-07-26
Also published as: CN116621548A

Abstract

The invention discloses low-alkali regenerated ecological concrete with high plant growth performance and a construction method thereof, wherein the ecological concrete comprises macroporous concrete based on regenerated aggregate, interstitial soil and covering soil, the macroporous concrete based on the regenerated aggregate comprises regenerated aggregate, cement, a water reducing agent and water, the interstitial soil comprises organic nutrient soil, fly ash, phosphogypsum and perlite, and the covering soil comprises organic nutrient soil, fly ash, phosphogypsum, sodium alginate, perlite, water-retaining resin and peat soil; the construction method comprises the following steps: paving a bulkhead on the side slope; preparing a macroporous concrete precast slab, and filling interstitial soil into the pores; placing the macroporous concrete precast slab filled with interstitial soil in each bulkhead on the side slope; paving a first layer of earthing, sowing grass seeds, paving a second layer of earthing and watering. The invention adopts the recycled aggregate to reduce the waste of natural aggregate and improve the water storage capacity of the slope protection structure, and adopts the macropores and low-alkali environment to improve the growth performance of plants.

Description

Low-alkali regenerated ecological concrete with high plant growth performance and construction method thereof

Technical Field

The invention belongs to the technical field of road and environmental engineering, and particularly relates to low-alkali regenerated ecological concrete with high vegetation performance and a construction method thereof.

Background

In mountains and hills characterized by wide-spread carbonate rock and general development of karst landscapes, the situation of 'one mountain is connected with one mountain' is common, so that the situation of digging is difficult to avoid in the road design and construction process, and a large number of slopes and steep slopes are formed. The slope treatment methods in the prior art are roughly classified into the following three types: firstly, no special protection treatment is carried out on the side slope which is relatively stable after excavation; secondly, reinforcing the side slope by means of shotcrete and the like; thirdly, reinforcing the side slope by adopting a flexible protective net. However, in either of the above methods, the green appearance of the mountain itself cannot be recovered. In addition, the phosphogypsum is randomly discharged and accumulated, so that the ecological environment is seriously damaged, not only is the underground water resource polluted, but also the land resource is wasted.

The side slope lacks green appearance, which is not only an attractive problem, but also a harmonious problem of traffic development and ecological protection. However, in the prior art, regarding the low-alkali ecological concrete technology, the slope protection performance and the use of recycled aggregate have not been studied; with regard to the technology of the regenerated ecological concrete, the problem of poor plant growth environment caused by alkalinity is not researched, and the problems of poor erosion resistance and serious loss of the existing slope covering soil are not researched.

In summary, the existing ecological slope protection concrete generally has the problems of natural aggregate waste, low plant growth rate, low plant propagation rate and the like in practical application, so that development of a novel ecological concrete which can promote carbon emission reduction and can achieve ecological restoration, has enough slope protection and anti-scouring performance and has good plant growth environment is urgently needed.

The invention patent with application publication number of CN102584127A discloses a recycled aggregate type vegetation ecological concrete and a preparation method thereof, wherein the ecological concrete is formed by combining the following materials in parts by weight: 1420-1580 parts of recycled coarse aggregate, 80-100 parts of recycled fine aggregate, 300-350 parts of cement, 50-70 parts of water and 6-10.5 parts of additive special for ZS-2; the preparation method comprises the steps of frame beam pouring, recycled aggregate preparation, ecological concrete pouring, grass seeds, soil and other materials filling in the pores of ecological concrete, surface covering, soil covering, curing and the like, wherein recycled aggregate with the particle size range of 20-40mm and recycled fine aggregate with the particle size range of 2.5-3.5mm are selected, cement, the recycled fine aggregate, water and a ZS-2 special additive are firstly added to prepare cement mortar, then the recycled coarse aggregate is added to stir, or the recycled coarse aggregate, the fine aggregate and 50% of water are firstly stirred, then the cement and the ZS-2 special additive are added to stir, and finally the rest water is added to stir. The technical scheme focuses on researching the regenerated ecological concrete and the preparation technology thereof, but does not consider the problems of poor plant growth environment, poor side slope earthing and anti-scouring performance and serious loss caused by the alkalinity of the regenerated ecological concrete; in addition, the technical scheme uses the recycled concrete aggregate, the alkalinity is higher, the water absorption and the water retention rate are poorer than those of red brick crushed aggregates, in addition, in the use process, the mixed concrete needs to be transported to the site, the long-distance transportation needs to be controlled within 1h, the temperature is above 250 ℃, and the use of the recycled concrete is limited by various conditions.

The invention patent with application publication number of CN114394807A discloses porous vegetation concrete capable of improving the vegetation performance, which is prepared from the following raw materials in percentage by mass: 180-200 parts of cement, 1200-1400 parts of recycled coarse aggregate, 8-15 parts of emulsion and 40-70 parts of water, wherein the emulsion consists of styrene-acrylic emulsion, VAE emulsion and styrene-butadiene emulsion, and the recycled coarse aggregate is formed by crushing construction waste demolishd materials, and has the particle size of 20-40 mm. The technical scheme focuses on researching the low-alkali ecological concrete technology, but does not consider the slope protection performance of the low-alkali ecological concrete; in addition, this solution produces a porous concrete and reduces alkalinity, but does not describe how soil is combined to accommodate plant growth, but provides a plant growth space.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides low-alkali recycled ecological concrete with high vegetation performance, which comprises macroporous concrete based on recycled aggregate, interstitial soil and covering soil; the mass percentage of each component in the macroporous concrete based on the recycled aggregate is 73-79wt% of the recycled aggregate, 16-21wt% of cement, 4-6wt% of water and 0.15-0.25wt% of water reducer; the filler soil comprises, by mass, 63-67% of organic nutrient soil, 8-12% of fly ash, 18-22% of phosphogypsum and 4-6% of perlite; the soil covering comprises, by mass, 58-62% of organic nutrient soil, 6-10% of fly ash, 14-18% of phosphogypsum, 2-4% of sodium alginate, 4-6% of perlite, 2-4% of water-retaining resin and 2-6% of peat soil.

Preferably, in the macroporous concrete based on the recycled aggregate, the recycled aggregate is red brick crushed aggregates with the grain size of 15-25mm, the cement is R.SAC42.5-grade low-alkalinity sulphoaluminate cement, and the water reducing agent is a polycarboxylate water reducing agent with the water reducing rate of 35%.

Because the aggregate in the common concrete is obtained by mountain-digging and quarrying, but the mountain-digging and quarrying seriously damages the ecological environment, and the requirement of the slope protection structure on the strength of the aggregate is not high, the waste recycled aggregate in the surplus construction waste is adopted. In the recycling process of the waste and old building aggregates, the addition amount of the recycled aggregates, the mass ratio of the recycled aggregates to other raw materials and the preparation process parameters are key technologies, and only the synergistic effect of the parameters is ensured, the expected technical effect of the invention can be obtained. The red brick broken stone is the red brick broken stone in the brick-concrete structure building, the shape is irregular, and the processing plant can process according to the standard requirement.

In any of the above schemes, preferably, in the interstitial soil, the particle size of the organic nutrient soil is not more than 5mm, the fly ash is F-class fly ash, the PH value of phosphogypsum is 4.17, each kilogram of phosphogypsum contains 4.6g of organic matters, the PH value of perlite is 6-7, and the particle size of perlite is 2-4mm.

In any of the above schemes, preferably, in the soil covering, the particle size of the organic nutrient soil is 10-20mm, the fly ash is F-class fly ash, the PH value of phosphogypsum is 4.17, each kilogram of phosphogypsum contains 4.6g of organic matters, the purity of sodium alginate is analytically pure, the particle size of the sodium alginate is 0.075mm, the PH value of the perlite is 6-7, the perlite with the particle size of 4-8mm accounts for 70%, the perlite with the particle size of 9-15mm accounts for 30%, the water-retaining resin is potassium polyacrylate, the particle size of the potassium polyacrylate is 0.075mm, the PH value of the peat soil is 5.5, and the particle size of the sodium alginate is 1-10mm.

Phosphogypsum is a byproduct of mining, and is generally randomly piled up due to weak reuse technology, but the random pile up causes serious environmental pollution. According to the invention, phosphogypsum is utilized in side slope protection, the phosphogypsum is used for preparing interstitial soil and covering soil, and in the preparation process, the addition amount of the phosphogypsum, the mass ratio of the phosphogypsum to other raw materials and the preparation process parameters are key technologies, so that the expected technical effect of the invention can be obtained only by ensuring the synergistic effect of the parameters.

The organic nutrient soil provides needed nutrition for plant growth; the water-retaining resin, sodium alginate and perlite provide sufficient moisture for germination and growth of plant seeds and root systems, the water-retaining resin can repeatedly store and release moisture after rainfall or spraying, so that an internal curing effect is achieved on concrete, shrinkage cracking is reduced, strength is improved, a film coating method can be adopted in a plant germination stage, seed germination is promoted by constructing a greenhouse, and moisture evaporation is reduced; phosphogypsum and fly ash can provide certain mineral elements for plants, reduce alkalinity in pores and improve the integrity and the scouring resistance of the plants. In the invention, the raw materials are taken as a whole, and the synergistic effect of the addition amount, the addition sequence and the technological parameters of each substance is controlled, so that the plant growth, the water retention, the grass fixation and the protection effects can be ensured.

In the invention, the low-alkali regenerated ecological concrete with high plant growth performance comprises macroporous concrete based on regenerated aggregate, interstitial soil and covering soil, and the proportion of the three substances in the ecological concrete is expressed by volume percent.

For one bulkhead, the total volume V of the low-alkali regenerated ecological concrete with high vegetation performance inside of the bulkhead is v=the volume v1 of the macroporous concrete precast slab+the volume V2 of the covering soil, wherein the volume v1 of the macroporous concrete precast slab is the length x width x height of the macroporous concrete precast slab, and the volume v2 of the covering soil is the length x width x height of the covering soil; volume of interstitial soil v3=volume of macroporous concrete precast slab v1×porosity of macroporous concrete based on recycled aggregate, volume of macroporous concrete based on recycled aggregate v4=volume of macroporous concrete precast slab V1-volume of interstitial soil V3. It can be seen that the volume percentage of the three substances in the ecological concrete varies with the size of the macroporous concrete precast slab, the height of the cover soil, and the porosity of the recycled aggregate-based macroporous concrete.

The invention also provides a construction method of the low-alkali regenerated ecological concrete with high plant growth performance, which uses the low-alkali regenerated ecological concrete with high plant growth performance to carry out construction and comprises the following steps in sequence:

Step one: paving square or diamond-shaped partition frames on a side slope by adopting ordinary Portland cement with the strength grade of 42.5, combining a plurality of partition frames together to form a frame on the side slope, and curing;

step two: preparing a macroporous concrete precast slab with the same shape as the bulkhead by adopting macroporous concrete based on recycled aggregate, and filling interstitial soil into the pores of the macroporous concrete precast slab;

step three: coating the periphery of the macroporous concrete precast slab filled with interstitial soil with dry and hard cement mortar, and then placing the cement mortar in each bulkhead on a side slope, wherein the bulkhead and the macroporous concrete precast slab in the bulkhead are positioned on the same plane;

step four: and paving a first layer of covering soil on the partition frame on the whole side slope and the macroporous concrete precast slab filled with the interstitial soil, uniformly sowing grass seeds on the first layer of covering soil, continuously paving a second layer of covering soil on the grass seeds, and uniformly watering the second layer of covering soil.

Preferably, in the first step, the method for paving square or diamond-shaped spacer frames on the side slope is as follows: drilling a hole at the common top point position of each adjacent four partition frames until the hole reaches the rock layer, cleaning the hole and embedding a reinforcing steel bar; and pouring ordinary Portland cement with the strength grade of 42.5 into the hole, pouring four frames of the bulkhead at the same time, and arranging a drain hole in the center of each frame.

The inner wall side length of the bulkhead is 101cm, the outer wall side length of the bulkhead is 116cm, the height of the bulkhead is 15cm, the diameter of the drain hole is 2-3cm, and the maintenance time of the bulkhead is 28 days.

In any of the above schemes, preferably, in the second step, the preparation method of the macroporous concrete precast slab comprises the following steps in sequence:

step (1): weighing the raw materials for standby according to the mass ratio of the design requirement;

step (2): sequentially pouring raw material recycled aggregate, cement, a water reducing agent and water into a stirrer for stirring to obtain macroporous concrete based on the recycled aggregate;

step (3): and uniformly paving the macroporous concrete based on the recycled aggregate in a prefabricating die, and curing and forming to obtain the macroporous concrete precast slab.

In the step (2), the stirring temperature of the raw material recycled aggregate, cement, water reducing agent and water is normal temperature, the stirring speed is 1500-7000r/min, the stirring time is 1-5min, and the porosity of the macroporous concrete based on the recycled aggregate is 25-30%.

In the step (3), the side length of the macroporous concrete precast slab is 100cm, the height of the macroporous concrete precast slab is 15cm, the curing temperature of the macroporous concrete precast slab is 18-22 ℃, the curing humidity is not lower than 95%, and the curing time is not less than 28 days.

In any of the above schemes, preferably, in the second step, the method for preparing the interstitial soil comprises the following steps in order:

step A: weighing the raw materials for standby according to the mass ratio of the design requirement;

and (B) step (B): pouring part of the organic nutrient soil and part of phosphogypsum into a stirrer for stirring to obtain a mixture of the organic nutrient soil and the phosphogypsum;

step C: pouring the rest organic nutrient soil, the fly ash, the perlite and the rest phosphogypsum into a stirrer for continuous stirring to obtain interstitial soil.

In the step B, the mass percentage of the organic nutrient soil to the organic nutrient soil is 40-50wt%, the mass percentage of the phosphogypsum to the phosphogypsum is 50-60wt%, the stirring temperature of the organic nutrient soil and the phosphogypsum is normal temperature, the stirring speed is 1500-7000r/min, and the stirring time is 1-5min.

In the step C, the stirring temperature of the rest organic nutrient soil, the fly ash, the perlite and the rest phosphogypsum is normal temperature, the stirring speed is 1500-7000r/min, and the stirring time is 1-5min.

In any of the above schemes, preferably, in the second step, the method for filling the gaps of the macroporous concrete precast slab with the interstitial soil comprises the following steps in sequence:

step a: a transparent acrylic plate is adopted to manufacture a box body with an opening at the upper part and the cross section shape the same as that of a macroporous concrete precast slab, a circle of gaskets are arranged at the position of 1/2 of the height of the box body along the periphery of the inner wall of the box body, and a connecting hole is arranged at the side surface below 1/2 of the height of the box body and is connected with a vacuum pump;

Step b: placing the macroporous concrete precast slab on a gasket in the box body from an opening above the box body, and sealing a gap between the macroporous concrete precast slab and the box body by using sealing cement;

step c: and paving the gap filling soil on the upper surface of the macroporous concrete precast slab, starting a vacuum pump to enable the gap filling soil on the upper surface of the macroporous concrete precast slab to pass through the pores, and falling to the bottom of the box body from the lower surface of the macroporous concrete precast slab, stopping vacuumizing when the gap filling soil at the bottom of the box body reaches a certain thickness, filling the gap filling soil in the pores of the macroporous concrete precast slab at the moment, removing sealing cement, and taking the macroporous concrete precast slab filled with the gap filling soil out of the box body.

In the step a, the side length of the inner wall of the box body is 101cm, the side length of the outer wall of the box body is 107cm, the height of the box body is 100cm, and the width of the gasket is 1.5cm and the thickness of the gasket is 1cm.

In the step c, the operation speed of the vacuum pump is 2800r/min, the pumping quantity is 20L/min, and the vacuum pumping is stopped when the thickness of interstitial soil at the bottom of the box body reaches 3-5 cm.

Or the method for filling the gap filling soil in the pores of the macroporous concrete precast slab comprises the following steps in sequence:

Step i: adding water into the interstitial soil to form the interstitial soil with fluidity for standby;

step ii: placing the macroporous concrete precast slab on a concrete vibration table, and spreading the gap filling soil with fluidity on the upper surface of the macroporous concrete precast slab;

step iii: and starting the concrete vibrating table, and stopping vibrating after vibrating for a certain time, wherein the gaps of the macroporous concrete precast slab can be filled with interstitial soil.

In the step i, the mass percent of each substance in the interstitial soil with fluidity is 55wt% of the interstitial soil and 45wt% of water; in step iii, the vibration frequency of the concrete vibration table is 2860 times/min, the vibration amplitude is 0.3-0.6mm, and the vibration time is 1-1.5min.

In any of the above schemes, preferably, in the fourth step, the preparation method of the covering soil includes the following steps in order:

step I: weighing the raw materials for standby according to the mass ratio of the design requirement;

step II: pouring part of organic nutrient soil, part of phosphogypsum and water-retaining resin into a stirrer for stirring to obtain a mixture of the organic nutrient soil, the phosphogypsum and the water-retaining resin;

step III: and pouring the rest of the organic nutrient soil, the fly ash, the perlite, the peat soil, the rest of the phosphogypsum and the sodium alginate into a stirrer for continuous stirring to obtain the earthing soil.

In the step II, the mass percentage of the organic nutrient soil to the organic nutrient soil is 40-50wt%, the mass percentage of the phosphogypsum to the phosphogypsum is 50-60wt%, the water retention resin is added completely, the stirring temperature of the organic nutrient soil and the water retention resin is normal temperature, the stirring speed is 1500-7000r/min, and the stirring time is 1-5min.

In the step III, the stirring temperature of the rest organic nutrient soil, the fly ash, the perlite, the peat soil, the rest phosphogypsum and the sodium alginate is normal temperature, the stirring speed is 1500-7000r/min, and the stirring time is 1-5min.

The thickness of the first layer of earthing is 0.5-1.5cm, the thickness of the second layer of earthing is 1.5-2.5cm, and the sum of the thicknesses of the two layers of earthing is 3cm; the sowing quantity of the grass seeds is 10-14g/m ² The method comprises the steps of carrying out a first treatment on the surface of the The sprinkling amount of the water is 15-20L/m ² 。

In any of the above schemes, preferably, in the fourth step, the grass seed is any one or more of festuca arundinacea, tripartite, ryegrass, baixi grass and white clover.

The low-alkali regenerated ecological concrete with high vegetation performance and the construction method thereof adopt the regenerated aggregate in the slope protection structure to reduce the waste of the natural aggregate and improve the water storage capacity of the slope protection structure, and adopt the macropores and the low-alkali environment to improve the growth performance of plants, thereby overcoming the weak items of the prior art on the research of slope protection performance, the regenerated aggregate and the plant growth environment and solving the problems of natural aggregate waste and low plant survival rate in the road slope protection.

Compared with the prior art, the invention adopts the waste recycled aggregate and phosphogypsum in the surplus construction waste, and builds a low-alkali plant growth environment, thereby not only meeting the performance requirements required by slope protection, but also meeting the environment and nutrition required by plant growth. The results of performance test experiments such as basic mechanical property test, slope protection alkali reduction test, vegetation coverage rate test and anti-scouring test show that the ecological concrete can well meet various requirements required by a side slope and a high steep side slope, can effectively ensure green ecological restoration and traffic safety of the side slope, and solves the problem of environmental pollution caused by accumulation of waste concrete and phosphogypsum in surplus construction waste.

Drawings

FIG. 1 is a schematic view showing a structure of a box body in which voids of a macroporous concrete precast slab are filled with interstitial soil in accordance with a preferred embodiment of a low-alkali recycled ecological concrete having high vegetation performance and a method of constructing the same according to the present invention;

FIG. 2 is a graph showing the cumulative soil loss at different rainfall intensities for the first to fifth embodiments of the low-alkali recycled ecological concrete with high vegetation performance and the construction method thereof according to the present invention;

FIG. 3 is a graph showing the cumulative soil loss for ecological concrete of different casing thicknesses at different rainfall intensities;

fig. 4 is a photograph of a scene of vegetation growth in the embodiment of fig. 1.

The reference numerals in the drawings indicate: 1-a box body, 2-a gasket, 3-a connecting hole, 4-a vacuum pump, 5-low-alkali regenerated ecological concrete with high plant growth performance and 6-vegetation.

Detailed Description

For a further understanding of the present invention, the present invention will be described in detail with reference to the following examples.

Embodiment one:

a preferred embodiment of the low alkali recycled ecological concrete having high vegetation performance according to the present invention includes recycled aggregate based macroporous concrete, interstitial soil and cover soil; the mass percentages of the components in the macroporous concrete based on the recycled aggregate are 73wt% of the recycled aggregate, 20.75wt% of cement, 6wt% of water and 0.25wt% of water reducer; the interstitial soil comprises the following components in percentage by mass of 63wt% of organic nutrient soil, 9wt% of fly ash, 22wt% of phosphogypsum and 6wt% of perlite; the soil covering comprises 58wt% of organic nutrient soil, 8wt% of fly ash, 16wt% of phosphogypsum, 4wt% of sodium alginate, 6wt% of perlite, 2wt% of water-retaining resin and 6wt% of peat soil.

In macroporous concrete based on recycled aggregate, the recycled aggregate is red brick crushed aggregates with the grain size of 15mm, the cement is R.SAC42.5-grade low-alkalinity sulphoaluminate cement, the water reducing agent is a polycarboxylate water reducing agent, and the water reducing rate is 35%. The red brick crushed aggregates of the embodiment are derived from construction waste generated by the old district removal engineering of Beijing, the original strength grade is C20-C50, the processing factory processes according to the standard requirements, and the processed red brick crushed aggregates are used in the embodiment.

In the interstitial soil, the particle size of the organic nutrient soil is 5mm, the fly ash is F-class fly ash, the PH value of phosphogypsum is 4.17, each kilogram of phosphogypsum contains 4.6g of organic matters, the PH value of perlite is 6, and the particle size of perlite is 2mm.

In the covering soil, the particle size of the organic nutrient soil is 10mm, the fly ash is F-class fly ash, the PH value of phosphogypsum is 4.17, each kilogram of phosphogypsum contains 4.6g of organic matters, the purity of sodium alginate is analytically pure, the particle size of the sodium alginate is 0.075mm, the PH value of perlite is 6, the perlite with the particle size of 4mm accounts for 70%, the perlite with the particle size of 9mm accounts for 30%, the water-retaining resin is potassium polyacrylate, the particle size of the sodium alginate is 0.075mm, the PH value of the peat soil is 5.5, and the particle size of the sodium alginate is 1mm.

The embodiment also provides a construction method of the low-alkali regenerated ecological concrete with high plant growth performance, which uses the low-alkali regenerated ecological concrete with Gao Zhi growth performance for construction and comprises the following steps in sequence:

In the first step, the method for paving square bulkhead on the side slope comprises the following steps: drilling a hole at the common top point position of each adjacent four partition frames until the hole reaches the rock layer, cleaning the hole and embedding a reinforcing steel bar; and pouring ordinary Portland cement with the strength grade of 42.5 into the hole, pouring four frames of the bulkhead at the same time, and arranging a drain hole in the center of each frame.

The inner wall side length of the bulkhead is 101cm, the outer wall side length of the bulkhead is 116cm, the height of the bulkhead is 15cm, the diameter of the drain hole is 3cm, and the maintenance time of the bulkhead is 28 days.

In the second step, the preparation method of the macroporous concrete precast slab comprises the following steps in sequence:

In the step (2), the stirring temperature of the raw material recycled aggregate, cement, water reducing agent and water is normal temperature, the stirring speed is 1500r/min, the stirring time is 5min, and the porosity of the macroporous concrete based on the recycled aggregate is 25%.

In the step (3), the side length of the macroporous concrete precast slab is 100cm, the height of the macroporous concrete precast slab is 15cm, the curing temperature of the macroporous concrete precast slab is 18 ℃, the curing humidity is 95%, and the curing time is 28 days.

In the second step, the preparation method of the interstitial soil comprises the following steps in sequence:

In the step B, the mass percentage of part of organic nutrient soil to the organic nutrient soil is 40wt%, the mass percentage of part of phosphogypsum to the phosphogypsum is 50wt%, the stirring temperature of the part of organic nutrient soil to the phosphogypsum is normal temperature, the stirring speed is 1500r/min, and the stirring time is 5min.

In the step C, the stirring temperature of the rest organic nutrient soil, the fly ash, the perlite and the rest phosphogypsum is normal temperature, the stirring speed is 1500r/min, and the stirring time is 5min.

In the second step, the method for filling the gap filling soil in the gaps of the macroporous concrete precast slab, which uses the box structure shown in fig. 1, comprises the following steps in sequence:

Step a: a transparent acrylic plate is adopted to manufacture a box body 1 with an opening at the upper part and the cross section shape the same as that of a macroporous concrete precast slab, a circle of gaskets 2 are arranged at the position of the height of the box body 1/2 along the periphery of the inner wall of the box body 1, a connecting hole 3 is arranged at the side surface below the height of the box body 1/2, and the connecting hole 3 is connected with a vacuum pump 4;

step b: placing the macroporous concrete precast slab on a gasket 2 in the box body 1 from an opening above the box body 1, and sealing a gap between the macroporous concrete precast slab and the box body by using sealing cement;

step c: and paving the gap filling soil on the upper surface of the macroporous concrete precast slab, starting a vacuum pump 4, enabling the gap filling soil on the upper surface of the macroporous concrete precast slab to pass through the pores, and falling to the bottom of the box body 1 from the lower surface of the macroporous concrete precast slab, stopping vacuumizing when the gap filling soil at the bottom of the box body 1 reaches a certain thickness, filling the gap filling soil in the pores of the macroporous concrete precast slab at the moment, removing the sealing cement, and taking the macroporous concrete precast slab filled with the gap filling soil out of the box body 1.

In the step c, the operation speed of the vacuum pump is 2800r/min, the pumping quantity is 20L/min, and the vacuum pumping is stopped when the thickness of the interstitial soil at the bottom of the box body reaches 3 cm.

In the fourth step, the preparation method of the covering soil comprises the following steps in sequence:

In the step II, the mass percentage of part of organic nutrient soil to the organic nutrient soil is 40wt%, the mass percentage of part of phosphogypsum to the phosphogypsum is 50wt%, the water retention resin is added, the stirring temperature of the three materials is normal temperature, the stirring speed is 1500r/min, and the stirring time is 5min.

In the step III, the stirring temperature of the rest organic nutrient soil, the fly ash, the perlite, the peat soil, the rest phosphogypsum and the sodium alginate is normal temperature, the stirring speed is 1500r/min, and the stirring time is 5min.

The thickness of the first layer of earthing is 0.5cm, the thickness of the second layer of earthing is 2.5cm, and the sum of the thicknesses of the two layers of earthing is 3cm; the grass seeds are selected from festuca arundinacea, and the sowing quantity is 10g/m ² The method comprises the steps of carrying out a first treatment on the surface of the The sprinkling amount of the water is 15L/m ² 。

In the embodiment, the low-alkali regenerated ecological concrete with high plant growth performance comprises macroporous concrete based on regenerated aggregate, interstitial soil and covering soil, and the proportion of the three substances in the ecological concrete is expressed by volume percent.

For one former, the volume v1=100 cm×100cm×15 cm=150000 cm of the macroporous concrete precast slab ³ Volume v3=150000 cm of interstitial soil ³ ×25%=37500cm ³ Recycled aggregate-based macroporous concrete has a volume v4=150000cm ³ －37500cm ³ =112500cm ³ The volume v2=100 cm×100cm×3 cm=30000 cm of the earth ³ . The volume percentage of each substance in the low-alkali regenerated ecological concrete with high planting performance is 62.5 percent of macroporous concrete based on regenerated aggregate, 20.83 percent of interstitial soil and 16.67 percent of covering soil.

The low-alkali regenerated ecological concrete with high vegetation performance and the construction method thereof adopt the regenerated aggregate in the slope protection structure to reduce the waste of the natural aggregate and improve the water storage capacity of the slope protection structure, adopt macropores and low-alkali environment to improve the growth performance of plants, and solve the problems of natural aggregate waste and low plant survival rate in the highway slope protection.

Embodiment two:

according to another preferred embodiment of the low-alkali regenerated ecological concrete with high plant growth performance and the construction method thereof, the composition substances, the preparation method of each substance, the preparation method of the ecological concrete, the performance test method, the principle, the beneficial effects and the like are basically the same as those of the first embodiment, except that:

for low alkali recycled ecological concrete with high plant growth performance: including recycled aggregate-based macroporous concrete, interstitial soil, and casing; the mass percentages of the components in the macroporous concrete based on the recycled aggregate are 79wt% of the recycled aggregate, 16.75wt% of cement, 4wt% of water and 0.15wt% of water reducer; the filler soil comprises 67 weight percent of organic nutrient soil, 11 weight percent of fly ash, 18 weight percent of phosphogypsum and 4 weight percent of perlite; the soil covering comprises, by mass, 62% of organic nutrient soil, 10% of fly ash, 14% of phosphogypsum, 3% of sodium alginate, 5% of perlite, 4% of water-retaining resin and 2% of peat soil.

In macroporous concrete based on recycled aggregate, the recycled aggregate is red brick crushed aggregates with the grain diameter of 25mm, the cement is R.SAC42.5-grade low-alkalinity sulphoaluminate cement, the water reducing agent is a polycarboxylate water reducing agent, and the water reducing rate is 35%.

In the interstitial soil, the particle size of the organic nutrient soil is 5mm, the fly ash is F-class fly ash, the PH value of phosphogypsum is 4.17, each kilogram of phosphogypsum contains 4.6g of organic matters, the PH value of perlite is 7, and the particle size of perlite is 4mm.

In the covering soil, the particle size of the organic nutrient soil is 20mm, the fly ash is F-class fly ash, the PH value of phosphogypsum is 4.17, each kilogram of phosphogypsum contains 4.6g of organic matters, the purity of sodium alginate is analytically pure, the particle size of the sodium alginate is 0.075mm, the PH value of perlite is 7, the particle size of perlite is 8mm, the perlite with the particle size of 8mm accounts for 70%, the particle size of perlite with the particle size of 15mm accounts for 30%, the water-retaining resin is potassium polyacrylate, the particle size of the water-retaining resin is 0.075mm, the PH value of the peat soil is 5.5, and the particle size of the sodium alginate is 10mm.

The construction method for the low-alkali regenerated ecological concrete with high plant growth performance comprises the following steps:

in the first step, the side length of the inner wall of the bulkhead is 101cm, the side length of the outer wall of the bulkhead is 116cm, the height of the bulkhead is 15cm, the diameter of the drain hole is 2cm, and the maintenance time of the bulkhead is 28 days.

In the second step, in the preparation method of the macroporous concrete precast slab, the stirring temperature of the raw material recycled aggregate, cement, water reducing agent and water is normal temperature, the stirring speed is 7000r/min, the stirring time is 1min, and the porosity of the macroporous concrete based on the recycled aggregate is 30%. The side length of the macroporous concrete precast slab is 100cm, the height of the macroporous concrete precast slab is 15cm, the curing temperature of the macroporous concrete precast slab is 22 ℃, the curing humidity is 95%, and the curing time is 28 days.

In the second step, in the preparation method of the interstitial soil, part of organic nutrient soil accounts for 50wt% of the organic nutrient soil, part of phosphogypsum accounts for 60wt% of the phosphogypsum, the stirring temperature of the organic nutrient soil and the phosphogypsum is normal temperature, the stirring speed is 7000r/min, and the stirring time is 1min. The stirring temperature of the rest organic nutrient soil, the fly ash, the perlite and the rest phosphogypsum is normal temperature, the stirring speed is 7000r/min, and the stirring time is 1min.

In the second step, in the method of filling the gap filling soil in the gaps of the macroporous concrete precast slab, the side length of the inner wall of the box body is 101cm, the side length of the outer wall of the box body is 107cm, the height of the box body is 100cm, and the width of the gasket is 1.5cm and the thickness of the gasket is 1cm. The operation speed of the vacuum pump is 2800r/min, the extraction amount is 20L/min, and the vacuum pumping is stopped when the thickness of interstitial soil at the bottom of the box body reaches 5 cm.

In the fourth step, in the preparation method of the covering soil, the mass percentage of part of organic nutrient soil to the organic nutrient soil is 50wt%, the mass percentage of part of phosphogypsum to the phosphogypsum is 60wt%, and all the water-retaining resin is added, wherein the stirring temperature of the three materials is normal temperature, the stirring speed is 7000r/min, and the stirring time is 1min. The stirring temperature of the rest organic nutrient soil, the fly ash, the perlite, the peat soil, the rest phosphogypsum and the sodium alginate is normal temperature, the stirring speed is 7000r/min, and the stirring time is 1min. The thickness of the first layer of earthing is 1.5cm, the thickness of the second layer of earthing is 1.5cm, and the sum of the thicknesses of the two layers of earthing is 3cm; the grass seeds are selected from festuca arundinacea, and the sowing quantity is 14g/m ² The method comprises the steps of carrying out a first treatment on the surface of the The sprinkling amount of the water is 20L/m ² 。

In this embodiment, for one spacer, the volume v1=100 cm×100cm×15 cm=150000 cm of the macroporous concrete precast slab ³ Volume v3=150000 cm of interstitial soil ³ ×30%=45000cm ³ Recycled aggregate-based macroporous concrete has a volume v4=150000cm ³ －45000cm ³ =105000cm ³ The volume v2=100 cm×100cm×3 cm=30000 cm of the earth ³ . The volume percentage of each substance in the low-alkali regenerated ecological concrete with high planting performance is 58.33 percent of macroporous concrete based on regenerated aggregate, 25 percent of interstitial soil and 16.67 percent of covering soil.

Embodiment III:

for low alkali recycled ecological concrete with high plant growth performance: including recycled aggregate-based macroporous concrete, interstitial soil, and casing; the mass percentages of the components in the macroporous concrete based on the recycled aggregate are 76wt% of the recycled aggregate, 18.8wt% of cement, 5wt% of water and 0.2wt% of water reducer; the interstitial soil comprises 65 weight percent of organic nutrient soil, 10 weight percent of fly ash, 20 weight percent of phosphogypsum and 5 weight percent of perlite; the soil covering comprises, by mass, 60% of organic nutrient soil, 9% of fly ash, 18% of phosphogypsum, 2% of sodium alginate, 4% of perlite, 3% of water-retaining resin and 4% of peat soil.

In macroporous concrete based on recycled aggregate, the recycled aggregate is red brick crushed aggregates with the grain diameter of 20mm, the cement is R.SAC42.5-grade low-alkalinity sulphoaluminate cement, the water reducing agent is a polycarboxylate water reducing agent, and the water reducing rate is 35%.

In the interstitial soil, the particle size of the organic nutrient soil is 5mm, the fly ash is F-class fly ash, the PH value of phosphogypsum is 4.17, each kilogram of phosphogypsum contains 4.6g of organic matters, the PH value of perlite is 6, and the particle size of perlite is 3mm.

In the covering soil, the particle size of the organic nutrient soil is 15mm, the fly ash is F-class fly ash, the PH value of phosphogypsum is 4.17, each kilogram of phosphogypsum contains 4.6g of organic matters, the purity of sodium alginate is analytically pure, the particle size of the sodium alginate is 0.075mm, the PH value of perlite is 6, the perlite with the particle size of 6mm accounts for 70%, the perlite with the particle size of 12mm accounts for 30%, the water-retaining resin is potassium polyacrylate, the particle size of the sodium alginate is 0.075mm, the PH value of the peat soil is 5.5, and the particle size of the sodium alginate is 5mm.

in the first step, the side length of the inner wall of the bulkhead is 101cm, the side length of the outer wall of the bulkhead is 116cm, the height of the bulkhead is 15cm, the diameter of the drain hole is 3cm, and the maintenance time of the bulkhead is 28 days.

In the second step, in the preparation method of the macroporous concrete precast slab, the stirring temperature of the raw material recycled aggregate, cement, water reducing agent and water is normal temperature, the stirring speed is 5000r/min, the stirring time is 3min, and the porosity of the macroporous concrete based on the recycled aggregate is 28%. The side length of the macroporous concrete precast slab is 100cm, the height of the macroporous concrete precast slab is 15cm, the curing temperature of the macroporous concrete precast slab is 20 ℃, the curing humidity is 95%, and the curing time is 28 days.

In the second step, in the preparation method of the interstitial soil, part of organic nutrient soil accounts for 45wt% of the organic nutrient soil, part of phosphogypsum accounts for 55wt% of phosphogypsum, the stirring temperature of the organic nutrient soil and the phosphogypsum is normal temperature, the stirring speed is 5000r/min, and the stirring time is 3min. The stirring temperature of the rest organic nutrient soil, the fly ash, the perlite and the rest phosphogypsum is normal temperature, the stirring speed is 5000r/min, and the stirring time is 3min.

In the second step, in the method of filling the gap filling soil in the gaps of the macroporous concrete precast slab, the side length of the inner wall of the box body is 101cm, the side length of the outer wall of the box body is 107cm, the height of the box body is 100cm, and the width of the gasket is 1.5cm and the thickness of the gasket is 1cm. The operation speed of the vacuum pump is 2800r/min, the extraction amount is 20L/min, and the vacuum pumping is stopped when the thickness of interstitial soil at the bottom of the box body reaches 4 cm.

In the fourth step, in the preparation method of the covering soil, part of organic nutrient soil accounts for 45wt% of organic nutrient soil, part of phosphogypsum accounts for 55wt% of phosphogypsum, and all water-retaining resin is added, wherein the stirring temperature of the three materials is normal temperature, the stirring speed is 5000r/min, and the stirring time is 3min. The stirring temperature of the rest organic nutrient soil, the fly ash, the perlite, the peat soil, the rest phosphogypsum and the sodium alginate is normal temperature, the stirring speed is 5000r/min, and the stirring time is 3min. The thickness of the first layer of earthing is 1.0cm, the thickness of the second layer of earthing is 2.0cm, and the sum of the thicknesses of the two layers of earthing is 3cm; the grass seeds are selected from festuca arundinacea, and the sowing quantity is 12g/m ² The method comprises the steps of carrying out a first treatment on the surface of the The sprinkling amount of the water is 18L/m ² 。

In this embodiment, for one spacer, the volume v1=100 cm×100cm×15 cm=150000 cm of the macroporous concrete precast slab ³ Volume v3=150000 cm of interstitial soil ³ ×28%=42000cm ³ Recycled aggregate-based macroporous concrete has a volume v4=150000cm ³ －42000cm ³ =108000cm ³ The volume v2=100 cm×100cm×3 cm=30000 cm of the earth ³ . The volume percentage of each substance in the low-alkali regenerated ecological concrete with high planting performance is 60 percent of macroporous concrete based on regenerated aggregate, 23.33 percent of interstitial soil and 16.67 percent of covering soil.

Embodiment four:

for low alkali recycled ecological concrete with high plant growth performance: including recycled aggregate-based macroporous concrete, interstitial soil, and casing; the mass percentages of the components in the macroporous concrete based on the recycled aggregate are 78wt%, 17.25wt% of cement, 4.5wt% of water and 0.25wt% of water reducer; the interstitial soil comprises 66 weight percent of organic nutrient soil, 8 weight percent of fly ash, 21 weight percent of phosphogypsum and 5 weight percent of perlite; the soil covering comprises 61wt% of organic nutrient soil, 6wt% of fly ash, 17wt% of phosphogypsum, 3.5wt% of sodium alginate, 5.5wt% of perlite, 2wt% of water-retaining resin and 5wt% of peat soil.

In macroporous concrete based on recycled aggregate, the recycled aggregate is red brick crushed aggregates with the grain diameter of 22mm, the cement is R.SAC42.5-grade low-alkalinity sulphoaluminate cement, the water reducing agent is a polycarboxylate water reducing agent, and the water reducing rate is 35%.

In the covering soil, the particle size of the organic nutrient soil is 18mm, the fly ash is F-class fly ash, the PH value of phosphogypsum is 4.17, each kilogram of phosphogypsum contains 4.6g of organic matters, the purity of sodium alginate is analytically pure, the particle size of the sodium alginate is 0.075mm, the PH value of perlite is 6, the particle size of perlite is 7mm, the perlite with the particle size of 70% is 10mm, the particle size of perlite is 30%, the water-retaining resin is potassium polyacrylate, the particle size of the water-retaining resin is 0.075mm, the PH value of the peat soil is 5.5, and the particle size of the sodium alginate is 8mm.

In the second step, in the preparation method of the macroporous concrete precast slab, the stirring temperature of the raw material recycled aggregate, cement, water reducing agent and water is normal temperature, the stirring speed is 3000r/min, the stirring time is 4min, and the porosity of the macroporous concrete based on the recycled aggregate is 26%. The side length of the macroporous concrete precast slab is 100cm, the height of the macroporous concrete precast slab is 15cm, the curing temperature of the macroporous concrete precast slab is 19 ℃, the curing humidity is 95%, and the curing time is 28 days.

In the second step, in the preparation method of the interstitial soil, part of organic nutrient soil accounts for 42wt% of the organic nutrient soil, part of phosphogypsum accounts for 52wt% of phosphogypsum, the stirring temperature of the organic nutrient soil and the phosphogypsum is normal temperature, the stirring speed is 3000r/min, and the stirring time is 4min. The stirring temperature of the rest organic nutrient soil, the fly ash, the perlite and the rest phosphogypsum is normal temperature, the stirring speed is 3000r/min, and the stirring time is 4min.

In the fourth step, in the preparation method of the covering soil, part of organic nutrient soil accounts for 42wt% of organic nutrient soil, part of phosphogypsum accounts for 52wt% of phosphogypsum, and all water-retaining resin is added, wherein the stirring temperature of the three materials is normal temperature, the stirring speed is 3000r/min, and the stirring time is 4min. The stirring temperature of the rest organic nutrient soil, the fly ash, the perlite, the peat soil, the rest phosphogypsum and the sodium alginate is normal temperature, the stirring speed is 3000r/min, and the stirring time is 4min. The thickness of the first layer of earthing is 1.2cm, the thickness of the second layer of earthing is 1.8cm, and the sum of the thicknesses of the two layers of earthing is 3cm; the grass seeds are selected from festuca arundinacea, and the sowing quantity is 11g/m ² The method comprises the steps of carrying out a first treatment on the surface of the The sprinkling amount of the water is 16L/m ² 。

In this embodiment, for one spacer, the volume v1=100 cm×100cm×15 cm=150000 cm of the macroporous concrete precast slab ³ Volume v3=150000 cm of interstitial soil ³ ×26%=39000cm ³ Recycled aggregate-based macroporous concrete has a volume v4=150000cm ³ －39000cm ³ =111000cm ³ The volume v2=100 cm×100cm×3 cm=30000 cm of the earth ³ . The low alkali recycled ecological concrete with high planting performance has the volume percentage of each substance of 61.67 percent of macroporous concrete based on recycled aggregate, 21.67 percent of interstitial soil and 16.67 percent of covering soil.

Fifth embodiment:

for low alkali recycled ecological concrete with high plant growth performance: including recycled aggregate-based macroporous concrete, interstitial soil, and casing; the mass percentages of the components in the macroporous concrete based on the recycled aggregate are 75wt% of the recycled aggregate, 19.25wt% of cement, 5.5wt% of water and 0.25wt% of water reducer; the interstitial soil comprises the following components in percentage by mass of 64wt% of organic nutrient soil, 12wt% of fly ash, 20wt% of phosphogypsum and 4wt% of perlite; the soil covering comprises 59 weight percent of organic nutrient soil, 7 weight percent of fly ash, 18 weight percent of phosphogypsum, 4 weight percent of sodium alginate, 5 weight percent of perlite, 4 weight percent of water-retaining resin and 3 weight percent of peat soil.

In macroporous concrete based on recycled aggregate, the recycled aggregate is red brick crushed aggregates with the production particle size of 18mm, the cement is R.SAC42.5-grade low-alkalinity sulphoaluminate cement, the water reducing agent is a polycarboxylate water reducing agent, and the water reducing rate is 35%.

In the covering soil, the particle size of the organic nutrient soil is 12mm, the fly ash is F-class fly ash, the PH value of phosphogypsum is 4.17, each kilogram of phosphogypsum contains 4.6g of organic matters, the purity of sodium alginate is analytically pure, the particle size of the sodium alginate is 0.075mm, the PH value of perlite is 6, the perlite with the particle size of 5mm accounts for 70%, the perlite with the particle size of 14mm accounts for 30%, the water-retaining resin is potassium polyacrylate, the particle size of the sodium alginate is 0.075mm, the PH value of the peat soil is 5.5, and the particle size of the sodium alginate is 4mm.

In the second step, in the preparation method of the macroporous concrete precast slab, the stirring temperature of the raw material recycled aggregate, cement, water reducing agent and water is normal temperature, the stirring speed is 6000r/min, the stirring time is 2min, and the porosity of the macroporous concrete based on the recycled aggregate is 29%. The side length of the macroporous concrete precast slab is 100cm, the height of the macroporous concrete precast slab is 15cm, the curing temperature of the macroporous concrete precast slab is 21 ℃, the curing humidity is 95%, and the curing time is 28 days.

In the second step, in the preparation method of the interstitial soil, the mass percent of part of organic nutrient soil accounts for 48wt% of organic nutrient soil, the mass percent of part of phosphogypsum accounts for 58wt% of phosphogypsum, the stirring temperature of the organic nutrient soil and the phosphogypsum is normal temperature, the stirring speed is 6000r/min, and the stirring time is 2min. The stirring temperature of the rest organic nutrient soil, the fly ash, the perlite and the rest phosphogypsum is normal temperature, the stirring speed is 6000r/min, and the stirring time is 2min.

In the fourth step, in the preparation method of the covering soil, the mass percentage of part of organic nutrient soil to the organic nutrient soil is 48wt%, the mass percentage of part of phosphogypsum to the phosphogypsum is 58wt%, and the water-retaining resin is added completely, wherein the stirring temperature of the three materials is normal temperature, the stirring speed is 6000r/min, and the stirring time is 2min. The stirring temperature of the rest organic nutrient soil, the fly ash, the perlite, the peat soil, the rest phosphogypsum and the sodium alginate is normal temperature, the stirring speed is 6000r/min, and the stirring time is 2min. The thickness of the first layer of earthing is 0.8cm, the thickness of the second layer of earthing is 2.2cm, and the sum of the thicknesses of the two layers of earthing is 3cm; the grass seeds are selected from festuca arundinacea, and the sowing quantity is 13g/m ² The method comprises the steps of carrying out a first treatment on the surface of the The sprinkling amount of the water is 19L/m ² 。

In this embodiment, for one spacer, the volume v1=100 cm×100cm×15 cm=150000 cm of the macroporous concrete precast slab ³ Volume v3=150000 cm of interstitial soil ³ ×29%=43500cm ³ Recycled aggregate-based macroporous concrete has a volume v4=150000cm ³ －43500cm ³ =106500cm ³ The volume v2=100 cm×100cm×3 cm=30000 cm of the earth ³ . So the volume percentage of each substance in the low-alkali regenerated ecological concrete with high plant growth performance is macroporous based on regenerated aggregate The gap concrete was 59.17%, the interstitial soil was 24.17%, and the cover soil was 16.67%.

For the first to fifth embodiments, the method for filling the voids of the macroporous concrete precast slab with the interstitial soil may also adopt the following steps:

step i: adding water into the interstitial soil to form the interstitial soil with fluidity for standby, wherein the mass percent of each substance in the interstitial soil with fluidity is 55wt% of the interstitial soil and 45wt% of the water;

step iii: starting a concrete vibration table, and stopping vibrating after vibrating for a certain time, wherein the gaps of the macroporous concrete precast slab can be filled with interstitial soil, the vibration frequency of the concrete vibration table is 2860 times/min, the vibration amplitude is 0.3-0.6mm, and the vibration time is 1-1.5min.

In the first to fifth embodiments, the addition amount, the addition order, and the process parameters of each substance are very important, and only the synergistic effect of these key parameters is ensured, the desired technical effect can be obtained.

Compared with the prior art, the embodiment adopts the waste recycled aggregate and phosphogypsum in the surplus construction waste, and builds a low-alkali plant growth environment, so that the performance requirements of slope protection can be met, and the environment and nutrition required by plant growth can be met. Tests such as basic mechanical property tests, slope protection alkali reduction tests, vegetation coverage rate tests and anti-scouring tests show that the ecological concrete of the embodiment can well meet various requirements required by slopes and high and steep slopes, can effectively ensure green ecological restoration and traffic safety of the slopes, and solves the problem of environmental pollution caused by accumulation of waste concrete and phosphogypsum in surplus construction waste. The specific cases of each test are as follows.

1. Porosity test

The continuous porosity test method of the pervious cement concrete in the appendix A of the application technical specification of the pervious cement concrete with the recycled aggregate of CJJ/T253-2016 is used for carrying out the continuous porosity test on the macroporous concrete based on the recycled aggregate, and the test results are shown in Table 1.

2. 28d compressive Strength test

The 28d compressive strength test was performed on recycled aggregate-based macroporous concrete filled with interstitial soil in the pores according to the specification requirements of the T0553-2005 concrete cube compressive strength test method, and the test results are shown in table 1.

3. PH value test

The pH value test is carried out by taking the macroporous concrete based on the recycled aggregate and interstitial soil therein as a whole, and the test instrument used is a Shanghai Lei Ci PH meter laboratory bench acidometer (PHS-25-3E). And (3) carrying out 28d standard maintenance on the test block, then carrying out drying treatment, wherein the drying temperature is 105-110 ℃ and the drying time is 24 hours, after the drying is finished, placing the test block into a container containing distilled water for soaking, wherein the distilled water submerges the test block in the table 1-3mm, and after the test block is soaked for 24 hours, measuring the PH value by using an acidometer, wherein the test result is shown in the table 1.

4. Vegetation coverage test

And (3) culturing the vegetation low-alkali regenerated ecological concrete which is sown with grass seeds, covered with covering soil and watered with water for 10 days, and then performing vegetation coverage test by adopting a needling method. For the ecological concrete in one bulkhead, the shape is a square with the side length of 100cm, the side length of the square is marked every 10cm, and then the marks are respectively connected in the horizontal direction and the vertical direction by using sample square ropes, so that 121 intersecting points are formed in a conformal manner. 100 crossing points are selected from 121 crossing points at will, a fine needle with the diameter of 2mm is used for being vertically inserted from the upper part of the vegetation, if the fine needle is contacted with the root of the vegetation, the existence is recorded, if the fine needle is not contacted with the root of the vegetation, the nonexistence is recorded, and finally the vegetation coverage rate is calculated. Vegetation coverage= (number of records "have". Times.total number of needle sticks) ×100%, test results are shown in table 1.

Table 1 results of examples one to five for porosity, 28d compressive strength, PH, vegetation coverage test

5. Anti-scour test

Adopting a ZKSB-1 rotary downward-spraying type rainfall device, setting the rainfall intensity to be 30mm/h and 50mm/h, setting the gradient of a test piece to be 45 degrees, changing a rainwater recovery tank every 10min, pouring sediment in the full rainwater recovery tank into a special rainfall barrel, stopping rainfall after the diameter is 20cm and the caliber is 7cm to 60min, and collecting all runoff sediment samples. After the rainfall is finished, the soil quantity in each process is tidied, the data are recorded, the supernatant is poured off after the soil quantity is static for 24 hours, and the soil quantity is weighed after the supernatant is placed in an oven at 105 ℃ to be dried for 24 hours, so that the accumulated soil loss quantity is obtained, and the accumulated soil loss quantity is specifically shown in figure 2.

Based on the first embodiment, other conditions were kept unchanged, and only the total thickness of the casing was changed, and when the total thickness of the casing was 1cm (the thickness of the first casing and the thickness of the second casing were both 0.5 cm), the total thickness of the casing was 2cm (the thickness of the first casing and the thickness of the second casing were both 1 cm), the total thickness of the casing was 3cm (the thickness of the first casing and the thickness of the second casing were both 0.5cm and 2.5cm, respectively, i.e., the case of the first embodiment), the total thickness of the casing was 4cm (the thickness of the first casing and the thickness of the second casing were both 1.5cm and 2.5 cm), the total thickness of the casing was 5cm (the thickness of the first casing and the thickness of the second casing were both 2.5 cm), and the cumulative soil loss at 30mm/h and 50mm/h of rainfall intensity was as shown in FIG. 3. FIG. 3 shows that the total thickness of the cover soil is preferably 3cm because the cumulative soil loss is minimized when the total thickness of the cover soil is 3cm under the same conditions.

6. Plant growth height test

Because of the longer test period, the invention only chooses to test the vegetation growth height of embodiment one. The vegetation growth height was measured every day from the day of grass germination, and the measurement data was recorded, as shown in table 2, on the 6 th day after grass seeds were sown, covered with soil and watered. In measuring vegetation height, a vegetation measurement is selected that is height-averaged.

Table 2 vegetation growth height measurement of example one

The photograph of the vegetation growing site in the first embodiment is shown in fig. 4, and it is seen that the vegetation 6 grows well on the low-alkali regenerated ecological concrete 5 with high vegetation performance, and the growth is stable.

When the vegetation growth conditions of the first embodiment are tracked on site, other peripheral slope vegetation is synchronously tracked, and the vegetation growth conditions of the slope are taken as a comparison example. The aggregate of the comparative example is recycled concrete, the recycled concrete is different from the recycled red brick crushed aggregates of the first example, although the recycled concrete and the recycled red brick crushed aggregates are all waste building wastes, the recycled concrete is cement, the alkalinity is higher, the recycled red brick crushed aggregates are bricks, the alkalinity is lower, and in addition, the raw materials such as phosphogypsum, sodium alginate and water-retaining resin are not added in the comparative example, so that the moisture and the nutrition are lower. From the vegetation growth cases of the first and comparative examples, the vegetation growth situation of the first example was still good from the twelfth day, but the vegetation growth of the comparative example was slow and yellowing phenomenon started to occur after the fifteenth day, although there was little difference in growth situation from the first ten days from the germination of the grass seeds. In addition, the vegetation of the first embodiment can continue to grow in season without replacing ecological concrete, while the vegetation of the comparative embodiment can not continue to grow in season without replacing concrete.

The specific description is as follows: the technical scheme of the invention relates to a plurality of parameters, and the beneficial effects and remarkable progress of the invention can be obtained by comprehensively considering the synergistic effect among the parameters. In addition, the value ranges of all the parameters in the technical scheme are obtained through a large number of tests, and aiming at each parameter and the mutual combination of all the parameters, the inventor records a large number of test data, and the specific test data are not disclosed herein for a long period of time.

It will be appreciated by those skilled in the art that the low alkali recycled ecological concrete with high vegetation performance and the construction method thereof of the present invention include any combination of the above-described summary of the invention and detailed description of the invention and the parts shown in the drawings, which are limited in space and are not described in detail in order to simplify the description. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The low-alkali recycled ecological concrete with high plant growth performance comprises macroporous concrete based on recycled aggregate, interstitial soil and covering soil, and is characterized in that: the mass percentage of each component in the macroporous concrete based on the recycled aggregate is 73-79wt% of the recycled aggregate, 16-21wt% of cement, 4-6wt% of water and 0.15-0.25wt% of water reducing agent, wherein the recycled aggregate is red brick crushed aggregates with the grain size of 15-25mm, and the cement is R.SAC42.5-grade low-alkalinity sulphoaluminate cement; the filler soil comprises, by mass, 63-67wt% of organic nutrient soil, 8-12wt% of fly ash, 18-22wt% of phosphogypsum and 4-6wt% of perlite, wherein the pH value of the phosphogypsum is 4.17, each kilogram of phosphogypsum contains 4.6g of organic matters, the pH value of the perlite is 6-7, and the particle size of the perlite is 2-4mm; the weight percentage of each component in the covering soil is 58-62wt%, 6-10wt% of fly ash, 14-18wt% of phosphogypsum, 2-4wt% of sodium alginate, 4-6wt% of perlite, 2-4wt% of water-retaining resin and 2-6wt% of peat soil, wherein the pH value of phosphogypsum is 4.17, each kilogram of phosphogypsum contains 4.6g of organic matters, the pH value of perlite is 6-7, the perlite with the particle size of 4-8mm accounts for 70%, the perlite with the particle size of 9-15mm accounts for 30%, the pH value of peat soil is 5.5, and the particle size of peat soil is 1-10mm;

The construction method of the low-alkali regenerated ecological concrete with Gao Zhi performance comprises the following steps in sequence:

step four: paving a first layer of covering soil on the partition frame on the whole side slope and the macroporous concrete precast slab filled with interstitial soil, uniformly sowing grass seeds on the first layer of covering soil, continuously paving a second layer of covering soil on the grass seeds, and uniformly watering the second layer of covering soil;

step C: pouring the rest organic nutrient soil, the fly ash, the perlite and the rest phosphogypsum into a stirrer for continuous stirring to obtain interstitial soil;

in the step B, the mass percentage of part of organic nutrient soil to the organic nutrient soil is 40-50wt%, the mass percentage of part of phosphogypsum to the phosphogypsum is 50-60wt%, the stirring temperature of the organic nutrient soil and the phosphogypsum is normal temperature, the stirring speed is 1500-7000r/min, and the stirring time is 1-5min; in the step C, the stirring temperature of the rest organic nutrient soil, the fly ash, the perlite and the rest phosphogypsum is normal temperature, the stirring speed is 1500-7000r/min, and the stirring time is 1-5min;

in the second step, the method for filling the gap filling soil in the gaps of the macroporous concrete precast slab comprises the following steps in sequence:

step c: paving gap filling soil on the upper surface of the macroporous concrete precast slab, starting a vacuum pump to enable the gap filling soil on the upper surface of the macroporous concrete precast slab to pass through the pores, and falling to the bottom of the box body from the lower surface of the macroporous concrete precast slab, stopping vacuumizing when the gap filling soil at the bottom of the box body reaches a certain thickness, filling the gap filling soil in the pores of the macroporous concrete precast slab at the moment, removing sealing cement, and taking the macroporous concrete precast slab filled with the gap filling soil out of the box body;

in the step a, the side length of the inner wall of the box body is 101cm, the side length of the outer wall of the box body is 107cm, the height of the box body is 100cm, and the width of the gasket is 1.5cm and the thickness of the gasket is 1cm; in the step c, the operation speed of the vacuum pump is 2800r/min, the extraction amount is 20L/min, and when the thickness of interstitial soil at the bottom of the box body reaches 3-5cm, the vacuum pumping is stopped;

step III: pouring the rest organic nutrient soil, fly ash, perlite, peat soil, rest phosphogypsum and sodium alginate into a stirrer for continuous stirring to obtain covered soil;

in the step II, the mass percentage of part of organic nutrient soil to the organic nutrient soil is 40-50wt%, the mass percentage of part of phosphogypsum to the phosphogypsum is 50-60wt%, the water retention resin is added completely, and the stirring temperature of the three materials is normal temperature and stirringThe speed is 1500-7000r/min, and the stirring time is 1-5min; in the step III, the stirring temperature of the rest organic nutrient soil, the fly ash, the perlite, the peat soil, the rest phosphogypsum and the sodium alginate is normal temperature, the stirring speed is 1500-7000r/min, and the stirring time is 1-5min; the thickness of the first layer of earthing is 0.5-1.5cm, the thickness of the second layer of earthing is 1.5-2.5cm, and the sum of the thicknesses of the two layers of earthing is 3cm; the sowing quantity of the grass seeds is 10-14g/m ² The method comprises the steps of carrying out a first treatment on the surface of the The sprinkling amount of the water is 15-20L/m ² 。

2. The low alkali recycled ecological concrete with high plant growth performance according to claim 1, characterized in that: in the macroporous concrete based on the recycled aggregate, the water reducing agent is a polycarboxylate water reducing agent, and the water reducing rate is 35%.

3. The low alkali recycled ecological concrete with high plant growth performance according to claim 2, characterized in that: in the interstitial soil, the particle size of the organic nutrient soil is not more than 5mm, and the fly ash is F-class fly ash.

4. The low alkali recycled ecological concrete with high plant growth performance according to claim 3, wherein: in the covering soil, the particle size of the organic nutrient soil is 10-20mm, the fly ash is F-class fly ash, the purity of sodium alginate is analytically pure, the particle size of the sodium alginate is 0.075mm, the water-retaining resin is potassium polyacrylate, and the particle size of the water-retaining resin is 0.075mm.

5. The low alkali recycled ecological concrete with high plant growth performance according to claim 4, wherein: step one, paving square or diamond-shaped spacer frames on a side slope, namely drilling a hole at the common vertex position of each adjacent four spacer frames until the hole reaches a rock layer, cleaning the hole and embedding a reinforcing steel bar; pouring ordinary Portland cement with the strength grade of 42.5 into the hole, pouring four frames of the bulkhead at the same time, and arranging a drain hole in the center of each frame; the inner wall side length of the bulkhead is 101cm, the outer wall side length of the bulkhead is 116cm, the height of the bulkhead is 15cm, the diameter of the drain hole is 2-3cm, and the maintenance time of the bulkhead is 28 days.

6. The low alkali recycled ecological concrete with high plant growth performance according to claim 5, wherein: in the second step, the preparation method of the macroporous concrete precast slab comprises the following steps in sequence,

step (3): uniformly paving the macroporous concrete based on the recycled aggregate in a prefabricating die, and curing and forming to obtain a macroporous concrete precast slab;

in the step (2), the stirring temperature of the raw material recycled aggregate, cement, water reducing agent and water is normal temperature, the stirring speed is 1500-7000r/min, the stirring time is 1-5min, and the porosity of the macroporous concrete based on the recycled aggregate is 25-30%; in the step (3), the side length of the macroporous concrete precast slab is 100cm, the height of the macroporous concrete precast slab is 15cm, the curing temperature of the macroporous concrete precast slab is 18-22 ℃, the curing humidity is not lower than 95%, and the curing time is not less than 28 days.

7. The low alkali recycled ecological concrete with high plant growth performance according to claim 6, characterized in that: in the second step, another method for filling the gap filling soil in the gaps of the macroporous concrete precast slab comprises the following steps in sequence,

step iii: starting a concrete vibrating table, and stopping vibrating after vibrating for a certain time, wherein gaps of the macroporous concrete precast slab can be filled with interstitial soil;