Waste plastic regenerated shotcrete and preparation method thereof

Abstract

The application discloses a kind of waste plastics regeneration shotcrete and preparation method thereof, belong to waste plastic processing technical field.The raw material of waste plastics regeneration shotcrete of the application includes cement, coarse aggregate and fine aggregate, wherein, the fine aggregate part uses plastic granule, the plastic granule is hollow structure with intercommunicating aperture formed by plastic strip, and the aperture communicates the outside with its inside of granule.The structure of plastic granule is optimized in the application, intercommunicating aperture is formed in it, so as to facilitate cement paste to fill therein, so that the structural strength of concrete can be effectively improved, and the adhesion between plastic granule and cement paste is improved, the problem that the application of concrete is limited due to the lower strength of plastic and the poor adhesion between plastic and cement paste in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of waste plastic processing, and more particularly relates to a waste plastic regenerated shotcrete and a preparation method thereof. BACKGROUND

[0002] With the development of economic construction and urbanization construction, the volume of infrastructure construction is huge, and the demand for concrete is also increasing day by day. At present, the coarse and fine aggregates used in the preparation of shotcrete are mostly natural minerals and natural river sand, but the use of natural sandstone resources has many problems, such as high transportation cost, long construction period, and the limited quantity of natural sandstone. Obviously, it is not a long-term solution to consume natural resources in large quantities. Over-exploitation of natural sandstone can also lead to a series of problems such as resource scarcity, environmental pollution, and land degradation.

[0003] At the same time, there are many problems in the exploitation of rock-made machine-made sand. The particles larger than 2.5mm and smaller than 0.08mm in machine-made sand may be too many, which will affect the workability and strength of the concrete. Poorly graded machine-made sand can cause the bonding force between the cement paste and the aggregate in the concrete to decrease, thereby increasing the rebound rate of the shotcrete. Therefore, it is urgent to find a reasonable, economical and environmentally friendly material to replace natural aggregate, which can not only solve the problem of over-exploitation of mineral resources, but also achieve resource recycling.

[0004] At present, the production of waste plastics is huge, which causes waste of land resources and soil pollution, and even air and water pollution. Therefore, it is very important to find a suitable recycling way for waste plastics.

[0005] Due to the characteristics of light weight, low cost, and chemical stability of waste plastics, the application of waste plastic particles to replace concrete aggregate in shotcrete can reduce the weight of concrete, thereby making the concrete more easily sprayed. However, waste plastics are not widely used to replace concrete aggregate at present, mainly due to the following reasons: 1. Low strength: compared with sand and stone aggregate, the compressive strength of plastic itself is lower, which will also reduce the compressive strength of concrete; 2. Poor adhesion to cement: the surface of plastic material is smoother than that of natural aggregate, so the adhesion to cement hydration products is poor, which leads to a decrease in concrete strength; 3. Irregular shape: natural aggregate is weathered in nature and is mostly elliptical or circular without corners, while the particles formed by crushing waste plastics are mostly irregular in shape and have many corners, which is not conducive to the compactness of concrete. SUMMARY

[0006] The application aims to provide a waste plastic regenerated shotcrete and a preparation method thereof, so as to solve the technical problem that the existing shotcrete generally uses natural ores and natural river sand as aggregates, resulting in overexploitation of ore resources; and the application of waste plastics in concrete is limited due to the low strength and poor adhesion of waste plastics to cement.

[0007] To achieve the above-mentioned purpose, the technical scheme provided by the application is as follows:

[0008] The application provides a waste plastic regenerated shotcrete, which comprises cement, coarse aggregate and fine aggregate, wherein the fine aggregate is partially replaced by plastic particle bodies.

[0009] The plastic particle bodies are hollow structures formed by plastic strips and have interconnected pores, and the pores are connected between the outside and the inside of the particle bodies.

[0010] It should be noted that the specific structure of the plastic particle bodies is not limited in the application, as long as the inside of the plastic particle bodies is formed with interconnected pores and the pores are connected to the outside of the particle bodies, so that the cement can be filled in the pores.

[0011] According to any of the technical schemes of the application, the mass percentage of the plastic particle bodies in the fine aggregate is 10% to 20%, so as to prevent the excessive addition of the plastic particle bodies from adversely affecting the overall structural strength and other performance of the concrete.

[0012] According to any technical solution of the present invention, the porosity of the plastic particles in the shotcrete reaches 5% to 20%, which can not only ensure the overall structural strength of the obtained concrete, but also effectively improve the bonding performance between the plastic particles and the cement hydration products.

[0013] According to any technical solution of the present invention, the shotcrete has a coarse aggregate with a particle size of 5mm-10mm, and the fine aggregate comprises particles with a particle size less than 0.5mm, a particle size between 0.5mm and 2mm, and a particle size between 2mm and 5mm. The mass percentages of particles with a particle size less than 0.5mm, a particle size between 0.5mm and 2mm, and a particle size between 2mm and 5mm in the fine aggregate are 30%-35%, 45%-50%, and 20%-25%, respectively. More preferably, the mass ratio of the three particle sizes is 3:5:2. Through particle size distribution optimization among aggregates of different sizes, the structural strength of the resulting concrete can be further guaranteed.

[0014] According to any of the technical solutions of the present invention, the shotcrete fine aggregate comprises plastic particles and manufactured sand, and the amount of plastic particles added and the particle size distribution are determined based on the gradation defects of recycled coarse aggregate and manufactured sand.

[0015] According to any technical solution of the present invention, the shotcrete contains recycled coarse aggregate, and plastic particles can be used to replace part of the recycled coarse aggregate. Based on the particle size distribution defects of the recycled coarse aggregate and manufactured sand, plastic particles of a specific particle size range and mass are added, thereby effectively solving the problem that the workability and strength of concrete are affected by the gradation defects of existing recycled coarse aggregate and manufactured sand. It also ensures the bond strength between cement paste and aggregate in the concrete and increases the rebound rate of shotcrete. More preferably, the mass ratio of recycled coarse aggregate to plastic particles in the coarse aggregate is (4-9):1, thereby effectively ensuring the structural strength of the recycled concrete. More preferably, the recycled coarse aggregate is recycled concrete or granite.

[0016] According to any technical solution of the present invention, the total admixture of coarse and fine aggregates in the shotcrete is 1700-1800 kg / m³. 3 Furthermore, the mass of fine aggregate accounts for 45% to 55% of the total aggregate (fine aggregate + coarse aggregate).

[0017] According to any technical solution of the present invention, the shotcrete uses ordinary Portland cement with a dosage of 400-500 kg / m³. 3 ; and / or a water-reducing agent is also added to the concrete to adjust its fluidity, at a dosage of 6.8 kg / m³. 3 ~7.8kg / m 3; and / or the concrete is further added with a quick-setting agent, and the adding amount of the quick-setting agent is 30-38kg / m 3 ; and / or the adding amount of water in the concrete is 150-200kg / m 3 . By optimizing the adding amount of the water-reducing agent and / or the quick-setting agent, the fluidity of the concrete can be effectively ensured. It should be noted that the types of the water-reducing agent and the quick-setting agent are not limited, and the existing water-reducing agent and quick-setting agent for concrete can be directly used, for example, the water-reducing agent can be a polycarboxylic acid water-reducing agent, a naphthalene series water-reducing agent, etc.

[0018] According to any of the technical solutions of the present application, the shotcrete is further added with a thickening agent, which is preferably an industrial-grade polyacrylamide, and the adding amount of the thickening agent is 0.01kg / m 3 ~0.03kg / m 3 . Since the plastic particles do not absorb water, they are easy to cause the concrete to bleed water, and the plastic particles are not uniformly distributed and float in the concrete. Therefore, on the one hand, the structure of the plastic particles is optimized, and on the other hand, the specific type of the thickening agent is used, so that the above situation can be effectively improved, and the uniformity of the distribution of the plastic in the concrete is ensured. The molecular weight of the polyacrylamide is further preferably 1.2×10 7 . Meanwhile, other components or admixtures can be added to the concrete as needed.

[0019] According to any of the technical solutions of the present application, the shotcrete has a 1-day compressive strength of 25-37Mpa and a 28-day compressive strength of 40-70Mpa.

[0020] The present application also provides a preparation method of the shotcrete regenerated from waste plastics, which comprises: uniformly mixing raw materials containing cement, coarse aggregate and fine aggregate in water, and the stirring time is preferably not less than 3 minutes. During the stirring process, the cement paste is filled into the pores of the plastic particles, so that the plastic particles and the concrete form an integral whole.

[0021] According to any of the technical solutions of the present application, the plastic particles are used to replace part of the recycled coarse aggregate, and the mass ratio of the recycled coarse aggregate to the plastic particles in the coarse aggregate is (4-9):1.

[0022] In summary, compared with the prior art, the technical solutions provided by the present application can achieve the following beneficial effects:

[0023] (1) The present application optimizes the structure of the plastic particle body, and the inside of the plastic particle body is formed with interconnected pores, so that the cement slurry can be filled into the pores, thereby effectively improving the structural strength of the concrete, and improving the adhesion between the plastic particle body and the cement slurry, so that part of the natural fine aggregate can be replaced, the grading defects of the natural aggregate can be overcome, and the problem that the plastic cannot be widely used in the concrete due to the low strength and poor adhesion between the plastic and the cement slurry in the prior art can be solved.

[0024] (2) The present application further optimizes the addition amount and particle size grading of the coarse aggregate and the fine aggregate (especially the plastic particle body), and the porosity of the plastic particle body, so that the overall structural strength, workability and adhesion between the aggregate and the cement slurry of the concrete can be further ensured.

[0025] (3) The present application optimizes the types and addition amounts of the water reducing agent and the thickening agent, so that the fluidity of the concrete can be effectively ensured, and the uniformity of the distribution of the plastic particle body in the concrete can be improved, thereby ensuring the use performance of the concrete. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The structure of the plastic particle body of the embodiment of the present application is shown in the figure.

[0027] In the figure: 1, plastic particle body; 2, cement slurry. DETAILED DESCRIPTION

[0028] In order to further understand the content of the present application, the present application will be described in detail in combination with specific embodiments.

[0029] Embodiment 1

[0030] The waste plastic regenerated shotcrete of the present embodiment is prepared from ordinary portland cement, coarse aggregate, fine aggregate, water reducing agent and thickening agent. The coarse aggregate is recycled coarse aggregate (specifically recycled concrete), and the particle size is 5mm-10mm. The fine aggregate comprises plastic particle body and machine-made sand. The plastic particle body has a hollow structure with interconnected pores formed by a plurality of plastic strips, and the pores communicate the outside of the particle body with the inside of the particle body. The porosity of the plastic particle body is 20%.

[0031] Specifically, the water reducing agent used in the present embodiment is polycarboxylic acid water reducing agent, and the addition amount is 7.3kg / m 3 . The thickening agent used is industrial grade polyacrylamide (molecular weight 1.2×10 7 ), and the addition amount is 0.02kg / m 3 . The cement addition amount is 488kg / m 3 , and the water addition amount is 164kg / m 3The total amount of coarse aggregate and fine aggregate in this embodiment is 1728 kg / m 3 The mass ratio of fine aggregate to coarse aggregate is 51:49, and the fine aggregate includes particles with a particle size of less than 0.5 mm, a particle size of 0.5 mm-2 mm, and a particle size of 2 mm-5 mm. In this embodiment, the mass ratio of the fine aggregate with a particle size of less than 0.5 mm, a particle size of 0.5 mm-2 mm, and a particle size of 2 mm-5 mm is 3:5:2. The fine aggregate with a particle size of less than 0.5 mm and a particle size of 2 mm-5 mm is machine-made sand, and the fine aggregate with a particle size of 0.5 mm-2 mm is obtained by mixing the plastic particle body and machine-made sand at a mass ratio of 1:4.

[0032] The preparation method of the sprayed concrete in this embodiment, according to the particle size grading defects of the recycled coarse aggregate and the machine-made sand, additionally adds part of the plastic particle body with a particle size of 0.5 mm-2 mm as fine aggregate. The raw materials are mixed and stirred uniformly, and the stirring time is not less than 3 minutes. The cement paste is filled into the plastic particle body in the stirring process, so that the plastic particle body and the concrete form a whole, and finally the waste plastic recycled sprayed concrete in this embodiment is obtained. The 1-day compressive strength of the concrete obtained in this embodiment is 35 MPa, and the 28-day compressive strength is 65 MPa.

[0033] Embodiment 2

[0034] The waste plastic recycled sprayed concrete in this embodiment includes ordinary portland cement, coarse aggregate, fine aggregate, water reducing agent, and thickening agent. The coarse aggregate is recycled coarse aggregate (specifically, recycled concrete), and the particle size is 5 mm-10 mm. The fine aggregate includes plastic particle body and machine-made sand. The plastic particle body is a hollow structure with interconnected pores formed by a plurality of plastic strips, and the pores communicate the outside and the inside of the particle body. Specifically, the plastic particle body in this embodiment is a hollow spherical structure with interconnected pores formed by the mutual interlaced winding of plastic strips, and the porosity of the plastic particle body is 15%.

[0035] The water reducing agent in this embodiment is a naphthalene-based water reducing agent, and the amount is 6.8 kg / m 3 kg / m 3 The thickening agent is an industrial-grade polyacrylamide (molecular weight 1.2×10 7 ), and the amount is 0.01 kg / m 3 kg / m 3 The cement amount is 500 kg / m 3 , and the water amount is 200 kg / m 3 The total amount of coarse aggregate and fine aggregate in this embodiment is 1700 kg / m 3The mass percentage of the fine aggregate is 45%, and the fine aggregate contains particles with a particle size less than 0.5 mm, a particle size of 0.5 mm-2 mm, and a particle size of 2 mm-5 mm. In the fine aggregate of this embodiment, the mass percentages of the particles with a particle size less than 0.5 mm, a particle size of 0.5 mm-2 mm, and a particle size of 2 mm-5 mm are 35%, 45%, and 20%, respectively. The fine aggregate with a particle size of 0.5 mm-2 mm and the fine aggregate with a particle size of 2 mm-5 mm are both machine-made sand. The fine aggregate with a particle size less than 0.5 mm is a mixture of plastic particle bodies and machine-made sand. The mass percentage of the plastic particle bodies in the total amount of the fine aggregate is 15%.

[0036] The preparation method of the sprayed concrete of this embodiment is as follows. According to the particle size grading defects of the recycled coarse aggregate and the machine-made sand, a part of plastic particle bodies with a particle size less than 0.5 mm is additionally added as the fine aggregate. The raw materials are mixed and stirred together until they are uniformly mixed, and the stirring time is not less than 3 minutes. The cement paste is filled into the plastic particle bodies in the stirring process, so that the plastic particle bodies and the concrete form an integral whole. Finally, the waste plastic regenerated sprayed concrete of this embodiment is obtained (as shown in Figure 1 The schematic diagram of the cement paste 2 filling into the internal voids of the plastic particle bodies 1). The 1-day compressive strength of the concrete obtained in this embodiment is 32 MPa, and the 28-day compressive strength is 58 MPa.

[0037] Embodiment 3

[0038] The waste plastic regenerated sprayed concrete of this embodiment is basically the same as that of Embodiment 2 in terms of the raw material composition, except that the dosage of the water reducing agent in this embodiment is 7.8 kg / m 3 , the dosage of the thickening agent is 0.03 kg / m 3 , the dosage of the cement is 400 kg / m 3 , and the dosage of the water is 150 kg / m 3 . The coarse aggregate used in this embodiment is recycled coarse aggregate (specifically, recycled granite), and the particle size is 5 mm-10 mm. The total dosage of the coarse aggregate and the fine aggregate is 1800 kg / m 3 , and the mass percentage of the fine aggregate is 55%. The fine aggregate contains particles with a particle size less than 0.5 mm, a particle size of 0.5 mm-2 mm, and a particle size of 2 mm-5 mm.

[0039] In the fine aggregate of this embodiment, the mass percentages of the particles with a particle size less than 0.5 mm, a particle size of 0.5 mm-2 mm, and a particle size of 2 mm-5 mm are 31%, 45%, and 24%, respectively. The fine aggregate with a particle size less than 0.5 mm and the fine aggregate with a particle size of 0.5 mm-2 mm are both machine-made sand. The fine aggregate with a particle size of 2 mm-5 mm is a mixture of plastic particle bodies and machine-made sand. The mass percentage of the plastic particle bodies in the total amount of the fine aggregate is 20%.

[0040] The preparation method of the sprayed concrete of the embodiment, according to the particle size grading defects of the recycled coarse aggregate and the machine-made sand, additionally adds part of the plastic particle body with the particle size of 2mm-5mm as the fine aggregate, mixes and stirs the raw materials together uniformly, the stirring time is not less than 3 minutes, the cement paste is filled into the plastic particle body in the stirring, the plastic particle body and the concrete form a whole, and finally the waste plastic recycled sprayed concrete of the embodiment is obtained. The 1-day compressive strength of the concrete obtained in the embodiment is 28Mpa, and the 28-day compressive strength is 55MPa.

[0041] Embodiment 4

[0042] The waste plastic recycled sprayed concrete of the embodiment, the raw materials of which include ordinary portland cement, coarse aggregate, fine aggregate, water reducing agent, thickening agent and accelerator, wherein the coarse aggregate adopts recycled coarse aggregate with the particle size of 5mm-10mm, and the fine aggregate includes plastic particle body and machine-made sand, the plastic particle body is a spherical structure with interconnected pores (the pores are distributed in a honeycomb shape) formed by the mutual interlaced winding of plastic strips, and the porosity of the plastic particle body is 5%.

[0043] Specifically, the water reducing agent in the embodiment adopts polycarboxylic acid water reducing agent, the mixing amount of which is 7.5kg / m 3 , the thickening agent adopts industrial-grade polyacrylamide (molecular weight 1.2×10 7 ), the mixing amount of which is 0.02kg / m 3 , the accelerator adopts AJ type accelerator, the mixing amount of which is 34.16kg / m 3 ; the cement mixing amount is 450kg / m 3 , and the water mixing amount is 175g / m 3 . The total mixing amount of the coarse aggregate and the fine aggregate in the embodiment is 1780kg / m 3 , the mass ratio of the fine aggregate to the coarse aggregate is 51:49, and the fine aggregate includes particles with the particle size less than 0.5mm, the particle size of 0.5mm-2mm and the particle size of 2mm-5mm, and the mass ratio of the particles with the particle size less than 0.5mm, the particle size of 0.5mm-2mm and the particle size of 2mm-5mm is 3:5:2. The fine aggregate with the particle size of 2mm-5mm adopts machine-made sand, and the fine aggregate with the particle size less than 0.5mm and the particle size of 0.5mm-2mm are both mixed by the plastic particle body and the machine-made sand, and the adding amount of the plastic particle body with the particle size less than 0.5mm accounts for 7% of the total amount of the fine aggregate, and the adding amount of the plastic particle body with the particle size of 0.5mm-2mm accounts for 5% of the total amount of the fine aggregate.

[0044] The preparation method of the sprayed concrete of the embodiment, according to the particle size grading defects of the recycled coarse aggregate and the machine-made sand, additionally adds part of plastic particle bodies with a particle size less than 0.5 mm and a particle size of 0.5 mm-2 mm as fine aggregate, mixes and stirs the raw materials together uniformly, the stirring time is not less than 3 minutes, the cement slurry is filled into the plastic particle bodies in the stirring, the plastic particle bodies form a whole with the concrete, and finally the waste plastic recycled sprayed concrete of the embodiment is obtained. The 1-day compressive strength of the concrete obtained in the embodiment is 36 MPa, and the 28-day compressive strength is 68 MPa.

[0045] Embodiment 5

[0046] The waste plastic recycled sprayed concrete of the embodiment has a raw material composition basically same as that of embodiment 4, and the main difference is that the mixing amount of the water reducing agent in the embodiment is 7.0 kg / m 3 , the mixing amount of the thickening agent is 0.01 kg / m 3 , the mixing amount of the cement is 415 kg / m 3 , the mixing amount of the water is 180 kg / m 3 , and the mixing amount of the quick-setting agent is 38 kg / m 3 .

[0047] In addition, the total mixing amount of the coarse aggregate and the fine aggregate in the embodiment is 1760 kg / m 3 , the mass ratio of the fine aggregate is 48%, and the fine aggregate with a particle size less than 0.5 mm and a particle size of 2 mm-5 mm is all machine-made sand, and the mass ratios (relative to the total amount of the fine aggregate) of the machine-made sand with the particle sizes are 30% and 25%, respectively, and the fine aggregate with a particle size of 0.5 mm-2 mm is mixed by the machine-made sand and the plastic particle bodies according to a mass ratio of 2:1.

[0048] The preparation method of the sprayed concrete of the embodiment mixes and stirs the raw materials together uniformly, the stirring time is not less than 3 minutes, the cement slurry is filled into the plastic particle bodies in the stirring, the plastic particle bodies form a whole with the concrete, and finally the waste plastic recycled sprayed concrete of the embodiment is obtained. The 1-day compressive strength of the concrete obtained in the embodiment is 27 MPa, and the 28-day compressive strength is 53 MPa.

[0049] Embodiment 6

[0050] The waste plastic recycled sprayed concrete of the embodiment has a raw material composition basically same as that of embodiment 4, and the main difference is that the mixing amount of the water reducing agent in the embodiment is 7.4 kg / m 3 , the mixing amount of the thickening agent is 0.03 kg / m 3 , the mixing amount of the cement is 460 kg / m 3 , the mixing amount of the water is 175 kg / m 3 , and the mixing amount of the quick-setting agent is 30 kg / m 3 .

[0051] In addition, the total amount of coarse aggregate and fine aggregate in the embodiment is 1728 kg / m 3 , the mass percentage of fine aggregate is 53%, and the coarse aggregate is composed of recycled coarse aggregate and plastic particle bodies in a mass ratio of 4:1, the mass ratio of fine aggregate with a particle size less than 0.5 mm, a particle size of 0.5 mm-2 mm, and a particle size of 2 mm-5 mm is 3:5:2, wherein the fine aggregate with a particle size less than 0.5 mm and a particle size of 0.5 mm-2 mm is machine-made sand, and the fine aggregate with a particle size of 2 mm-5 mm is composed of plastic particle bodies and machine-made sand in a mass ratio of 1:1.

[0052] The preparation method of the sprayed concrete of the embodiment additionally adds plastic particle bodies as part of the coarse aggregate and part of the fine aggregate, mixes and stirs each raw material uniformly, the stirring time is not less than 3 minutes, the cement paste is filled into the plastic particle bodies in the stirring, the plastic particle bodies and the concrete form a whole, and finally the waste plastic regenerated sprayed concrete of the embodiment is obtained. The 1-day compressive strength of the concrete obtained in the embodiment is 25 MPa, and the 28-day compressive strength is 40 MPa.

[0053] Example 7

[0054] The waste plastic regenerated sprayed concrete of the embodiment has the same raw material composition as example 6, and the main difference is that the coarse aggregate in the embodiment is composed of recycled coarse aggregate and plastic particle bodies in a mass ratio of 9:1, the 1-day compressive strength of the concrete obtained in the embodiment is 30 MPa, and the 28-day compressive strength is 49 MPa.

[0055] Comparative Example 1

[0056] The waste plastic regenerated sprayed concrete of the comparative example has the same raw material composition and ratio as example 2, and the main difference is that the plastic particle bodies in the embodiment are obtained by directly crushing the waste plastic, the 1-day compressive strength of the concrete in the comparative example is 20 MPa, the 28-day compressive strength is 33 MPa, and the directly crushed plastic particle bodies have many corners on the surface, which is not conducive to the strength of the concrete.

[0057] Comparative Example 2

[0058] The waste plastic regenerated sprayed concrete of the comparative example has the same raw material composition and ratio as example 2, and the main difference is that the porosity of the plastic particle bodies in the comparative example is 35%, the 1-day compressive strength of the concrete in the comparative example is 22 MPa, the 28-day compressive strength is 35 MPa, and the porosity of the plastic particle bodies is too high, the combination of a large amount of cement paste and plastic particle bodies reduces the amount of free paste, resulting in reduced fluidity of the freshly mixed concrete.

[0059] Comparative Example 3

[0060] The waste plastic regenerated shotcrete of the present comparative example has the same raw material composition and proportion as that of Example 2, and the main difference between the present comparative example and Example 2 is that the porosity of the plastic particle body in the present comparative example is 2%. Due to the too low porosity of the plastic particle body, the cement slurry is difficult to combine with the plastic particle body, and compared with Example 2, the bonding effect of the plastic particle body and the cement product in the present comparative example is not good, resulting in a decrease in the strength of the concrete.

[0061] Comparative Example 4

[0062] The waste plastic regenerated shotcrete of the present comparative example has the same raw material composition and proportion as that of Example 2, and the main difference between the present comparative example and Example 2 is that the porosity of the plastic particle body in the present comparative example is 2%. Due to the too low porosity of the plastic particle body, the cement slurry is difficult to combine with the plastic particle body, and compared with Example 2, the bonding effect of the plastic particle body and the cement product in the present comparative example is not good, resulting in a decrease in the strength of the concrete.

[0063] Comparative Example 5

[0064] The waste plastic regenerated shotcrete of the present comparative example has the same raw material composition and proportion as that of Example 2, and the main difference between the present comparative example and Example 2 is that the porosity of the plastic particle body in the present comparative example is 2%. Due to the too low porosity of the plastic particle body, the cement slurry is difficult to combine with the plastic particle body, and compared with Example 2, the bonding effect of the plastic particle body and the cement product in the present comparative example is not good, resulting in a decrease in the strength of the concrete.

[0065] Comparative Example 6

[0066] The waste plastic regenerated shotcrete of the present comparative example has the same raw material composition and proportion as that of Example 2, and the main difference between the present comparative example and Example 2 is that the porosity of the plastic particle body in the present comparative example is 2%. Due to the too low porosity of the plastic particle body, the cement slurry is difficult to combine with the plastic particle body, and compared with Example 2, the bonding effect of the plastic particle body and the cement product in the present comparative example is not good, resulting in a decrease in the strength of the concrete. 3 3 Due to the unreasonable addition amount of the water reducing agent and the thickening agent, the fluidity of the obtained concrete is relatively poor, and the 1-day compressive strength of the obtained concrete in the present comparative example is 18 MPa, and the 28-day compressive strength is 30 MPa.

[0067] Comparative Example 7

[0068] The waste plastic regenerated shotcrete of the present comparative example has the same raw material composition and proportion as that of Example 2, and the main difference between the present comparative example and Example 2 is that the porosity of the plastic particle body in the present comparative example is 2%. Due to the too low porosity of the plastic particle body, the cement slurry is difficult to combine with the plastic particle body, and compared with Example 2, the bonding effect of the plastic particle body and the cement product in the present comparative example is not good, resulting in a decrease in the strength of the concrete.​

Claims

1. A waste plastic recycled shotcrete, characterized by, The raw material comprises cement, coarse aggregate and fine aggregate, wherein the fine aggregate part uses plastic particle bodies which are hollow structures with intercommunicating pores formed by plastic strips, and the pores communicate the outside of the particle bodies with the inside.

2. The waste plastic reclaimed jet concrete according to claim 1, characterized in that, The mass percentage of the plastic particle bodies in the fine aggregate is 10-20% of the total amount of the fine aggregate; and / or the porosity of the plastic particle bodies reaches 5-20%.

3. The waste plastic reclaimed jet concrete according to claim 2, characterized in that, The plastic particle bodies are multi-layer superimposed hollow structures with a whole wave shape formed by multiple plastic strips, or are porous spherical structures formed by interlaced winding of the plastic strips.

4. The waste plastic reclaimed shotcrete according to any one of claims 1-3, characterized in that, The particle size of the coarse aggregate is 5-10 mm, the fine aggregate comprises particles with a particle size less than 0.5 mm, a particle size of 0.5-2 mm and a particle size of 2-5 mm, and the mass percentages of the particles with a particle size less than 0.5 mm, a particle size of 0.5-2 mm and a particle size of 2-5 mm in the fine aggregate are 30-35%, 45-50% and 20-25% respectively.

5. The waste plastic reclaimed jet concrete according to claim 4, characterized in that, The cement uses ordinary Portland cement, and the mixing amount is 400-500 kg / m 3 ; and / or The concrete is also added with water reducing agent, and the mixing amount is 6.8kg / m 3 ~7.8kg / m 3 ; and / or The concrete also has a thickening agent added thereto, and the amount of the thickening agent is 0.01 kg / m 3 ~0.03 kg / m 3 ; and / or The concrete also has a quick-setting agent added thereto, and the amount of the quick-setting agent is 30-38 kg / m 3 ; and / or The water content in the concrete is 150-200 kg / m 3 ; and / or The total mixing amount of coarse aggregate and fine aggregate in the concrete is 1700-1800 kg / m 3 , and the mass percentage of fine aggregate in the total aggregate is 45%-55%.

6. The waste plastic reclaimed jet concrete according to claim 4, wherein, The fine aggregate comprises plastic particle bodies and machine-made sand, and the addition amount and particle size distribution of the plastic particle bodies are determined according to the grading defects of the recycled coarse aggregate and the machine-made sand.

7. The waste plastic reclaimed shotcrete according to claim 6, characterized in that, The coarse aggregate uses recycled coarse aggregate, or is a mixture of recycled coarse aggregate and plastic particle bodies.

8. The waste plastic reclaimed jet concrete according to claim 4, wherein, The 1-day compressive strength of the concrete is 25-37 MPa, and the 28-day compressive strength is 40-70 MPa.

9. A method of producing a waste plastic reclaimed shotcrete according to any one of claims 1 to 8, characterized by, Comprise: The raw material comprising cement, coarse aggregate and fine aggregate is stirred and mixed uniformly in water, and the cement paste fills into the pores of the plastic particle bodies during the stirring process, so that the plastic particle bodies and the concrete form a whole.

10. The method for preparing recycled waste plastic shotcrete according to claim 9, characterized in that, The coarse aggregate comprises recycled coarse aggregate and plastic particle bodies, and the mass ratio of the recycled coarse aggregate to the plastic particle bodies in the coarse aggregate is (4-9):1.

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