A solid waste-based geocell filler, its preparation method and application

Abstract

The present invention discloses a solid waste-based geocell filler, its preparation method and application. The solid waste-based geocell filler comprises, by mass parts, 100-200 parts of air-dried silt soil, 50-100 parts of solid waste-based curing agent, 10-20 parts of water and 0.1-2 parts of functional material; the solid waste-based curing agent comprises, by mass percentage, 10%-30% of cement, 15%-25% of slag, 5%-15% of fly ash, 20%-30% of steel slag, 10%-20% of carbide slag, 5%-10% of red mud, 10%-20% of rice husk ash and 5%-10% of desulfurized gypsum; the functional material is waste tire fragments with a particle size of 1-20 mm. The present invention innovatively adds tire fragments. After adding the tire fragments, the gel filled in the internal pores of the mixture composed of the curing agent and the silt is wrapped and entangled by the tire fragments, forming a stable three-dimensional network structure inside the soil particles, further restricting the rolling and movement of the soil particles, and improving the internal stability and overall strength of the solidified silt soil.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction materials, and particularly relates to a solid waste-based geocell filler, a preparation method thereof, and an application thereof. Background Art

[0002] A geocell is a kind of reinforcing material with a three-dimensional honeycomb structure formed by welding polymer sheets. Generally, multiple geocells are folded together for easy transportation and storage. When used in actual engineering, the geocell is unfolded at a certain angle, and fillers such as crushed stones, coarse sand, or muck are buried in the unfolded honeycomb grid, jointly forming an elastic flexible cushion layer with the geostructure, thereby enhancing the bearing capacity and anti-scouring ability of the soil. Currently, geocells are quite widely used, mainly for foundation treatment, slope protection, and retaining wall reinforcement. Especially on roads where heavy vehicles often travel, they can prevent or reduce the occurrence of ruts.

[0003] Generally, the fillers used in geocells include ordinary sand and gravel. The gravel and sand have larger particle sizes, higher strengths, good water permeability, easy density control, and are convenient for local material sourcing with relatively low economic costs, so they are frequently used in geotechnical engineering. However, with the development of the economy, problems such as resource waste and environmental pollution have become increasingly serious, so the utilization of solid waste is very necessary.

[0004] Some solid wastes such as fly ash, slag, steel slag, carbide slag, red mud, rice husk ash, and desulfurized gypsum have been widely used as cement substitute materials in building construction. However, these wastes are less used as geocell fillers, and there are few reports on improving the strength of solid waste-based geocell fillers. Summary of the Invention

[0005] In order to solve the problems of the prior art, the present invention provides a solid waste-based geocell filler, which comprises, by mass parts,

[0006] 100 - 200 parts of air-dried silt soil, 50 - 100 parts of solid waste-based curing agent, 10 - 20 parts of water, and 0.1 - 2 parts of functional material;

[0007] The solid waste-based curing agent comprises, by mass percentage, 10% - 30% cement, 15% - 25% slag, 5% - 15% fly ash, 20% - 30% steel slag, 10% - 20% carbide slag, 5% - 10% red mud, 10% - 20% rice husk ash, and 5% - 10% desulfurized gypsum;

[0008] The functional material is waste tire fragments with a particle size of 1 - 20 mm.

[0009] Further, the functional material is waste tire fragments with a particle size of 4.75 - 20 mm.

[0010] Further, the cement is ordinary Portland cement, and the strength grade is at least one of 42.5 MPa, 52.5 MPa, and 62.5 MPa.

[0011] Further, the particle sizes of slag, steel slag, carbide slag, red mud, rice husk ash, and desulfurized gypsum are less than 0.075 mm;

[0012] The particle size of fly ash is less than or equal to 0.0374 mm.

[0013] Further, the water content of the air-dried silt soil is lower than 0.5%.

[0014] Further, the average particle size of the solid waste-based geocell filler is 10 - 15 mm.

[0015] The present invention also provides a preparation method of the above-mentioned solid waste-based geocell filler, including,

[0016] Adding a solid waste-based curing agent to the air-dried silt soil, then adding water, and finally adding waste tire fragments, and stirring to obtain a cured silt soil mixture;

[0017] Putting the cured silt soil mixture into a mold and curing to obtain a cured specimen;

[0018] Crushing and sorting the particle sizes of the cured specimen to obtain the solid waste-based geocell filler.

[0019] In an embodiment of the present invention, after putting the cured silt soil mixture into the mold, sample preparation is carried out according to the static pressing sample preparation method, and the prepared specimen is wrapped with plastic wrap and placed in a constant temperature and humidity chamber, and cured for 28 days at a temperature of 20°C and a humidity of 95%. After curing for 28 days, it already has a relatively high strength.

[0020] In an embodiment of the present invention, use a small hammer to hammer along the central axis of the cylindrical specimen to form several cured soil particles with larger particle sizes (particle size greater than 40 mm), and then put the large soil particles into a small hammer crusher, control its crushing frequency, and use an intelligent vibrating screen machine to control its crushing particle size during the crushing process to ensure that the average particle size of the solid waste-based geocell filler is 10 - 15 mm.

[0021] The present invention also provides the application of the above-mentioned solid waste-based geocell filler, including,

[0022] Put the solid waste-based geocell filler into each unit of the geocell to jointly form a flexible cushion layer of the structure. Specifically, according to the different uses of the geocell and the compactness of the filler, the filling quality of the geocell is different, and the quality of the solid waste-based geocell filler is determined according to the specific use during the use process.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention innovatively adds tire fragments to some existing sludge treatment. After adding tire fragments, the gel filled in the internal pores of the mixture composed of silicate cement, fly ash, slag powder, steel slag and other solidifying agents and sludge is wrapped and entangled by the tire fragments. The easily bendable tire fragments are prone to form a stable three-dimensional network structure inside the soil particles, restricting the turning and movement of the soil particles, thereby improving the internal stability and overall strength of the solidified sludge soil.

[0025] 2. Compared with the existing similar fiber reinforcement technologies, the tire fragments have a certain width, and the network structure formed with the solidified sludge soil particles is more stable. For tire fragments with a certain width, if the length exceeds a certain value, due to external loads and the movement of the mixture, these long tire fragments are likely to separate from the sand particles and adjacent tire fragments, which will lead to a reduction in the shear stress at the sand-fragment interface. Therefore, tire fragments with a certain particle size are more helpful for improving the strength of the solidified sludge soil.

[0026] 3. For soft sludge foundation soils, due to the characteristics of high compressibility, high water permeability and low strength of the sludge, it is difficult to carry out mechanical operations on the foundation soil, causing great construction problems. The present invention can utilize sludge soft soil and industrial waste based on the idea of solid waste utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 Shows the overall effect diagram of the flexible cushion formed by the solid waste-based geocell filler prepared in Example 1 of the present invention and the geocell. DETAILED DESCRIPTION OF THE INVENTION

[0029] In the ranges disclosed in the present invention, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values and individual point values of each range, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the accompanying drawings of the specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] In the embodiments, the particle sizes of blast furnace slag, steel slag, carbide slag, red mud, rice husk ash, and desulfurized gypsum used are all less than 0.075 mm; the particle size of fly ash is less than or equal to 0.0374 mm; the waste tire fragments are obtained by crushing and sorting the waste tires to the required particle size. These contents will not be elaborated further.

[0032] Example 1

[0033] A preparation method of a solid waste-based geocell filler is as follows:

[0034] Step 1, sample preparation: Weigh 1624.96 g of air-dried silt soil with a moisture content of 0.2%, 763.78 g of solid waste-based curing agent (see Table 1 for details), 112.32 g of water, and 3.74 g of waste tire fragments (functional materials) with a particle size of 9.5 - 12.5 mm; add the solid waste-based curing agent to the air-dried silt soil, then add water, and finally add the waste tire fragments, and stir evenly to obtain a cured silt soil mixture; put the obtained cured silt soil mixture into a cylindrical mold with a diameter of 150 mm and a height of 50 mm, and prepare samples according to the static pressing method, and prepare 50 samples according to the same steps;

[0035] Table 1 Specific substances of the solid waste-based curing agent

[0036]

[0037] Step 2, curing: Wrap the samples prepared in Step 1 with plastic wrap and place them in a constant temperature and humidity curing box at a temperature of 20°C and a humidity of 95% for 28 days;

[0038] Step 3, crushing: Take out all the cured samples in Step 2, and use a small compaction hammer to crush them along the central axis of the cylindrical samples to obtain some larger-sized fragments (particle size greater than 40 mm);

[0039] Step 4, sorting: Put the fragments obtained in Step 3 into a small hammer crusher, control the time and number of hammer strikes of the hammer crusher, and use a vibrating sieve machine to repeatedly screen after each hammer strike to ensure that the average particle size of the fragments obtained after crushing is 12 mm, thus obtaining the solid waste-based geocell filler.

[0040] Examples 2 to 7

[0041] Examples 2 to 7 are basically the same as Example 1 in the preparation method. The only difference is that the particle sizes of the waste tire fragments of the functional materials are different. For the specific method, please refer to Example 1. The specific particle size selection is shown in Table 2.

[0042] Table 2 Particle Sizes of Waste Tire Fragments in Examples 1 to 7

[0043]

[0044]

[0045] Example 8

[0046] An application of a solid waste-based geocell filler is as follows.

[0047] Put the solid waste-based geocell filler prepared in Example 1 into each unit of the geocell according to a certain mass distribution to form a flexible cushion layer of the structure together with the geocell, as Figure 1 shown. During use, according to the different uses of the geocell and the compactness of the filler, the filling mass of the geocell is different. During use, determine the filler mass according to the specific use.

[0048] Comparative Examples 1 to 4

[0049] Comparative Examples 1 to 4 are basically the same as Example 1 in the preparation method. The only difference is that functional materials are not used or other materials are used as functional materials. For the specific method, please refer to Example 1. The specific selection of functional materials is shown in Table 3.

[0050] Table 3 Selection of Functional Materials in Comparative Examples 1 to 4

[0051] Functional material Comparative example 1 None Comparative example 2 <![CDATA[D 50 coarse sand with a size of 0.84 mm]]> Comparative example 3 <![CDATA[D 50 = gravel with a size of 7 mm]]> Comparative example 4 Basalt fiber with a length of 10 mm

[0052] Test Example

[0053] Refer to Part 1129-2006 of the standard JTG E50-2006 "Test Regulations for Geosynthetics in Highway Engineering" to conduct a direct shear friction characteristic test between the solid waste-based geocell fillers prepared in Examples 1 to 7 and Comparative Examples 1 to 4 and the geocells. Put the geocell into the lower shear box, and fill a certain mass of the solid waste-based geocell filler into the upper and lower shear boxes according to the operating procedures of the direct shear test. The shear strength test results are shown in Table 4.

[0054] Table 4 Shear Strength Results

[0055]

[0056]

[0057] As can be seen from the results in Table 4, using waste tire fragments with a size of 1 - 20 mm as functional materials in Examples 1 - 7 of the present invention and adding them to the air-dried silt soil and the mixed solid waste gel system significantly improved the shear strength. When controlling the particle size of the waste tire fragments to be 4.75 - 20 mm, it significantly exceeded that of traditional functional materials such as coarse sand, crushed stone, and basalt fiber. This is because after adding the tire fragments, the gel filled in the pores of the mixture composed of solidifying agents such as portland cement, fly ash, slag powder, and steel slag and the silt soil is wrapped and entangled by the tire fragments. The easily bendable tire fragments are prone to form a stable three-dimensional network structure inside the soil particles, restricting the flipping and movement of the soil particles, thereby improving the internal stability and overall strength of the solidified silt soil. Moreover, as a composite material, waste tires have unique advantages of good ductility and energy absorption capacity. This advantage is also manifested differently in tire fragments of different particle sizes. As the particle size of the tire fragments added to the soil increases, the shear strength of the soil shows a gradually increasing trend, and the brittleness index of the soil gradually decreases. This is because the particle size of the small-sized tire fragments is similar to that of the soil particles, and the soil can accommodate more small-sized tire fragments, increasing the soil stiffness. At this time, the voids generated by the rubber particles are occupied by the soil, while for the large-sized tire fragments, the rubber particles act as reinforcements for the soil. When the particle size of the tire fragments reaches the range of 9.5 mm - 12.5 mm, the shear strength of the soil reaches the peak value, the brittleness index reaches the lowest value, and the soil has the strongest energy absorption capacity. As the particle size of the tire fragments continues to increase (12.5 - 20 mm), the shear strength begins to show a decreasing trend, the brittleness index increases, and the energy absorption capacity decreases. This decrease in strength is caused by the reduction in the unit weight of the overly large-sized tire fragments. Therefore, when the particle size of the tire fragments is in the range of 9.5 mm - 12.5 mm, its performance is optimal. These results indicate that the solid waste-based geocell filler prepared in the examples of the present invention effectively utilizes the waste silt soil and industrial solid waste and can be applied to practical engineering projects.

[0058] Referring to the standard JTG 3430 - 2020 "Code for Highway Geotechnical Tests", part T0148 - 1993, unconfined compressive strength tests were carried out on the specimens after curing in the preparation methods of Examples 1 - 7 and Comparative Examples 1 - 4. The results are shown in Table 5.

[0059] Table 5 Unconfined Compressive Strength Results

[0060] As can be seen from the test results in Table 2, the unconfined compressive strength of the air-dried silt soil sample is very low, only 0.2 MPa. After using cement, slag, fly ash, steel slag, carbide slag, red mud, rice husk ash, and desulfurized gypsum as curing agents, the unconfined compressive strength increases significantly to 3.19 MPa. In addition, after adding a small amount of basalt fibers with a length of 10 mm, the unconfined compressive strength further increases to 4.2 MPa. It should be noted that in Examples 1-7 of the present invention, using waste tire fragments with a size of 1-20 mm as functional materials and adding them to the air-dried silt soil and mixed solid waste gel system can improve the unconfined compressive strength. Moreover, there is a trend of first increasing and then decreasing with the increase in the particle size of the waste tire fragments. When the particle size of the tire fragments is in the range of 9.5 mm to 12.5 mm, the unconfined compressive strength reaches the maximum value of 5.61 MPa.

[0061] In summary, the present invention uses cement, slag, fly ash, steel slag, carbide slag, red mud, rice husk ash, and desulfurized gypsum as curing agents, air-dried silt soil as the main body, and waste tire fragments with different particle sizes as functional materials to prepare a solid waste-based geocell filler, which can alleviate the problem of recycling silt soil, make up for the drawback of untimely soil treatment during the excavation of silt soil, make full use of industrial solid waste, reduce economic costs, and reduce environmental pollution. In addition, the present invention prepares a solid waste-based geocell filler with shear strength and unconfined compressive strength significantly superior to those of existing common materials (coarse sand, gravel, and basalt particles) by regulating the particle size of waste tire fragments, and has good application prospects.

[0062] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A solid waste-based geocell filler, characterized in that, Comprising, by mass parts, 100 to 200 parts of air-dried silt soil, 50 to 100 parts of solid waste-based curing agent, 10 to 20 parts of water, and 0.1 to 2 parts of functional material; The solid waste-based curing agent comprises, by mass percentage, 10% to 30% cement, 15% to 25% slag, 5% to 15% fly ash, 20% to 30% steel slag, 10% to 20% carbide slag, 5% to 10% red mud, 10% to 20% rice husk ash, and 5% to 10% desulfurized gypsum; The functional material is waste tire fragments with a particle size of 4.75 to 20 mm; The preparation method of the solid waste-based geocell filler comprises, Adding the solid waste-based curing agent to the air-dried silt soil, then adding water, and finally adding waste tire fragments, and stirring to obtain a cured silt soil mixture; Putting the cured silt soil mixture into a mold and curing to obtain a cured specimen; Crushing and sorting the particle size of the cured specimen to obtain the solid waste-based geocell filler.

2. The solid waste-based geocell filler according to claim 1, characterized in that, The cement is ordinary Portland cement with a strength grade of at least one of 42.5 MPa, 52.5 Mpa, and 62.5 MPa.

3. The solid waste-based geocell filler according to claim 1, characterized in that, The particle sizes of slag, steel slag, carbide slag, red mud, rice husk ash, and desulfurized gypsum are less than 0.075 mm; The particle size of fly ash is less than or equal to 0.0374 mm.

4. The solid waste-based geocell filler according to claim 1, characterized in that, The water content of the air-dried silt soil is lower than 0.5%.

5. The solid waste-based geocell filler according to any one of claims 1 to 4, characterized in that, The average particle size of the solid waste-based geocell filler is 10 to 15 mm.

6. An application of the solid waste-based geocell filler according to any one of claims 1 to 5, characterized in that, Comprising, Putting the solid waste-based geocell filler into each unit of the geocell to jointly form a flexible cushion layer of the structure with the geocell.

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