High-density and high-strength aggregate prepared by carbonizing mucky soil and preparation method of high-density and high-strength aggregate

Abstract

According to the high-density and high-strength aggregate prepared by carbonizing the mucky soil and the preparation method, the slaked lime and the water reducing agent are used for carrying out composite modification on the mucky soil, and on the basis of taking calcium carbonate obtained by carbonizing the slaked lime as a framework, free water in the mucky soil is released by fully utilizing the dispersion effect of the water reducing agent on a flocculation structure of the mucky soil; the water content is greatly reduced, the compactness is greatly improved, a net-shaped structure is constructed by utilizing the self structure, the cementitious property among soil particles is further enhanced, the mixture can meet the requirements of highway subgrade design specifications, the compactness is remarkably improved, the particle crushing strength is high, and the mixture has certain water resistance; and the main curing agent lime is used for capturing carbon dioxide, so that the artificial roadbed filler with stable properties and higher strength can be formed, the mucky soil, carbon dioxide and other wastes can be changed into artificial aggregates urgently needed in the traffic field, and the artificial roadbed filler has good service performance. The method effectively solves the problem of poor engineering properties of the mucky soil, provides a scheme for solving the problems of poor properties, difficult treatment and the like of the mucky soil, meets the requirements of green ecology and sustainable development, lays a foundation for application in the field of road engineering, and can also be popularized to other waste utilization fields.

Description

Technical Field

[0001] The invention belongs to the roadbed filling technology, and particularly relates to a high-density and high-strength aggregate made by carbonizing silty soil and a preparation method thereof. Background Art

[0002] As the size of cities in coastal areas continues to expand, cities located on silt-deposited coasts will produce a large amount of silty debris during the construction process. Its high water content and low strength make it impossible to use it in engineering projects, causing many projects to face the dilemma of having nowhere to put the debris, so that the projects are forced to stop.

[0003] With the growing demand for roadbed fillers, the construction and transportation industries have consumed a large amount of non-renewable natural resources in their rapid development, making artificial aggregates show great potential in the field. Summary of the invention

[0004] The first purpose of the present invention is to provide a method for preparing lime-modified silt roadbed filler particles which has a simple process flow and high strength and can transform silt soil, a waste soil, into modified silt soil, in order to address the problems of environmental pollution and land occupation in the prior art and the lack of traditional roadbed fillers.

[0005] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0006] A method for preparing high-density and high-strength aggregate made by carbonizing muddy soil, characterized in that the preparation method comprises the following steps:

[0007] S1. Dry the muddy soil and control the moisture content;

[0008] S2, remove impurities in the dried muddy soil and crush it;

[0009] S3, using the crushed muddy soil as a base material, adding a certain amount of slaked lime as a curing agent to the base material, and stirring evenly to obtain a first mixture;

[0010] S4, adding a water reducing agent to the first mixture to obtain a second mixture;

[0011] S5, adding water to the second mixture, mixing thoroughly to obtain solidified soil, the amount of water added being determined by the plastic limit method of rubbing strips; and compacting and granulating to control the quality of each particle;

[0012] S6. Carbonizing the compacted and granulated particles with carbon dioxide to obtain a carbonized soil product.

[0013] In silt soil, the silicon dioxide content is 67.5%, the aluminum oxide content is 14.6%, the iron oxide content is 4.66%, the calcium oxide content is 0.65%, and the magnesium oxide content is 1.29%.

[0014] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0015] As a preferred technical solution of the present invention: in step S1, the moisture content is controlled to be no more than 5%.

[0016] As a preferred technical solution of the present invention: in step S2, the crushed particle size of the silty soil is controlled to be no larger than 100 mesh.

[0017] As a preferred technical solution of the present invention: in step S3, the dry weight dosage of slaked lime is 20% to 30%.

[0018] As a preferred technical solution of the present invention: in step S3, the first mixture is slowly ground to a fineness of no more than 100 meshes.

[0019] As a preferred technical solution of the present invention: in step S4, the water reducer is a polycarboxylic acid high-efficiency water reducer with a fineness of no more than 100 mesh; the dosage of the water reducer is 0.2% to 1.0%.

[0020] For example: choose C1029 polycarboxylate water reducer (powder) produced by Suzhou Fuke Technology Co., Ltd.

[0021] As a preferred technical solution of the present invention: in step S4, the water reducing agent is a copolymer polymerized with acrylic acid, polyoxyethylene acrylate and sodium methacrylic acid sulfonate as monomers.

[0022] As a preferred technical solution of the present invention: in step S5, the mass of the particles after compaction and granulation is controlled to be 2.10g to 2.15g.

[0023] As a preferred technical solution of the present invention: in step S6, the conditions of the carbonization reaction are: temperature of 60° C., relative humidity of 60%, and carbonization reaction time of 6 hours.

[0024] Another object of the present invention is to provide a high-density and high-strength aggregate prepared by the method for preparing the high-density and high-strength aggregate prepared by carbonizing silty soil as described above.

[0025] The invention provides a high-density and high-strength aggregate made by carbonizing silty soil and a preparation method thereof. The invention utilizes slaked lime and a water reducer to carry out composite modification on silty soil with very weak engineering performance. On the basis of using calcium carbonate obtained by carbonizing slaked lime as a skeleton, the water reducer fully utilizes the dispersing effect of the water reducer on the flocculation structure of the silty soil to release free water therein, so that its moisture content is greatly reduced and its density is greatly improved. The structure thereof is utilized to construct a mesh structure, so as to further strengthen the cementation between soil particles, so that the mixture can meet the requirements of highway subgrade design specifications, and the density is significantly improved. The mixture has high unconfined compressive strength, certain water resistance and high economic benefit, and effectively solves the problems of poor engineering properties of silty soil, provides a solution for solving the problems of poor properties of silty soil and difficult treatment, meets the requirements of green ecology and sustainable development, lays a foundation for its application in the field of road engineering, and can also be extended to other waste utilization fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention provides a flow chart of a method for preparing a high-density and high-strength aggregate made by carbonizing silty soil.

[0027] Figure 2 This is a diagram showing the relationship between the unconfined compressive strength of slaked lime modified silt soil particles after carbonization and the amount of water reducer added. DETAILED DESCRIPTION

[0028] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0029] In order to measure the influence of the content of slaked lime and water reducing agent in the modified soil on the properties of the modified soil, the experimental proportions shown in Table 1 were adopted for improvement. The flow chart of the preparation method of high-density and high-strength aggregate made by carbonization of silty soil is shown in Figure 1 The water reducing agent in all the examples is C1029 polycarboxylate water reducing agent (powder) produced by Suzhou Fuke Technology Co., Ltd.

[0030] 1. Preparation Example

[0031] Example 1

[0032] 1) For muddy soil, spread it on site, dry it in the oven at 105℃, and control the moisture content to a low level (≤5%);

[0033] 2) removing impurities from the material in step 1, crushing the dry muddy soil with a pulverizer, using the crushed muddy soil as a base material, and mixing it with a mixer at a dry weight ratio of 20% slaked lime to obtain a first mixture;

[0034] 3) Calculate the dry weight of the first mixture obtained in step 2, use the water reducer as an additive, and mix the muddy soil and the water reducer at a dry weight content of 0.2% to obtain a second mixture;

[0035] 4) Using the first mixture obtained in step 2 as a base material, adding water according to the mass fraction and mixing thoroughly to obtain solidified soil;

[0036] 5) Compact and granulate the solidified soil obtained in step 4, and control the mass of each particle to be between 2.10-2.15g;

[0037] 6) The particles obtained in step 5 are carbonized and cured under the conditions of temperature 60° C., relative humidity 60%, and carbonization reaction time 6 h to obtain carbonized particles S1.

[0038] Example 2

[0039] The first mixture in step 4 of Example 1 is replaced by the second mixture, and the amount of the water reducing agent in the second mixture is 0.4%. The remaining steps are the same as those of Example 1 to obtain the roadbed filler S2.

[0040] Example 3

[0041] The first mixture in step 4 of Example 1 is replaced by the second mixture, and the amount of the water reducing agent in the second mixture is 0.6%. The remaining steps are the same as those of Example 1 to obtain the roadbed filler S3.

[0042] Example 4

[0043] The first mixture in step 4 of Example 1 is replaced by the second mixture, and the amount of the water reducing agent in the second mixture is 0.8%. The remaining steps are the same as those of Example 1 to obtain the roadbed filler S4.

[0044] Example 5

[0045] The first mixture in step 4 of Example 1 is replaced by the second mixture, and the amount of the water reducing agent in the second mixture is 1.0%. The remaining steps are the same as those of Example 1 to obtain the roadbed filler S5.

[0046] Example 6

[0047] 1) For muddy soil, spread it on site, dry it in the oven at 105℃, and control the moisture content to a low level (≤5%);

[0048] 2) removing impurities from the material in step 1, crushing the dry muddy soil with a pulverizer, using the crushed muddy soil as a base material, and mixing it with a mixer at a dry weight ratio of 30% slaked lime to obtain a first mixture;

[0049] 3) Calculate the dry weight of the first mixture obtained in step 2, use the water reducer as an additive, and mix the muddy soil and the water reducer at a dry weight content of 0.2% to obtain a second mixture;

[0050] 4) Using the first mixture obtained in step 2 as a base material, adding water according to the mass fraction and mixing thoroughly to obtain solidified soil;

[0051] 5) Compact and granulate the solidified soil obtained in step 4, and control the mass of each particle to be between 2.10-2.15g;

[0052] 6) The particles obtained in step 5 are carbonized and cured under the conditions of temperature 60° C., relative humidity 60%, and carbonization reaction for 6 hours to obtain carbonized particles S6.

[0053] Example 7

[0054] The first mixture in step 4 of Example 6 is replaced by the second mixture, and the amount of the water reducing agent in the second mixture is 0.4%. The remaining steps are the same as those of Example 6 to obtain the roadbed filler S7.

[0055] Example 8

[0056] The first mixture in step 4 of Example 6 is replaced by the second mixture, and the amount of the water reducing agent in the second mixture is 0.6%. The remaining steps are the same as those of Example 6 to obtain the roadbed filler S8.

[0057] Example 9

[0058] The first mixture in step 4 of Example 6 is replaced by the second mixture, and the amount of the water reducing agent in the second mixture is 0.8%. The remaining steps are the same as those of Example 6 to obtain the roadbed filler S9.

[0059] Example 10

[0060] The first mixture in step 4 of Example 6 is replaced by the second mixture, and the amount of the water reducing agent in the second mixture is 1.0%. The remaining steps are the same as those of Example 6 to obtain the roadbed filler S10.

[0061] Comparative Example 1

[0062] 1) For muddy soil, spread it on site, dry it in the oven at 105℃, and control the moisture content to a low level (≤5%);

[0063] 2) removing impurities from the material in step 1, crushing the dry muddy soil with a pulverizer, using the crushed muddy soil as a base material, and mixing it with a mixer at a dry weight ratio of 10% slaked lime to obtain a first mixture;

[0064] 3) Calculate the dry weight of the first mixture obtained in step 2, use the water reducer as an additive, and mix the muddy soil and the water reducer at a dry weight content of 0.2% to obtain a second mixture;

[0065] 4) Using the first mixture obtained in step 2 as a base material, adding water according to the mass fraction and mixing thoroughly to obtain solidified soil;

[0066] 5) Compact and granulate the solidified soil obtained in step 4, and control the mass of each particle to be between 2.10-2.15g;

[0067] 6) The particles obtained in step 5 are carbonized and cured under the conditions of temperature 60° C., relative humidity 60%, and carbonization reaction time 6 h to obtain carbonized particles D1.

[0068] Comparative Example 2

[0069] The first mixture in step 4 of comparative example 1 is replaced by the second mixture, and the amount of water reducing agent in the second mixture is 0.4%. The remaining steps are the same as comparative example 1 to obtain roadbed filler D2.

[0070] Comparative Example 3

[0071] The first mixture in step 4 of comparative example 1 is replaced by the second mixture, and the amount of water reducing agent in the second mixture is 0.6%. The remaining steps are the same as those of comparative example 1 to obtain roadbed filler D3.

[0072] Comparative Example 4

[0073] The first mixture in step 4 of comparative example 1 is replaced by the second mixture, and the amount of water reducing agent in the second mixture is 0.8%. The remaining steps are the same as comparative example 1 to obtain roadbed filler D4.

[0074] Comparative Example 5

[0075] The first mixture in step 4 of comparative example 1 is replaced by the second mixture, and the amount of water reducing agent in the second mixture is 1.0%. The remaining steps are the same as those of comparative example 1 to obtain roadbed filler D5.

[0076] 2. Unconfined compressive strength test:

[0077] In accordance with the "Test Procedures for Inorganic Binder Stabilized Materials for Highway Engineering" (JTGE51-2009).

[0078] The test results are listed in Table 1. Figure 2 middle.

[0079] Table 1

[0080]

[0081]

[0082] like Figure 2 As shown in Table 1, for the groups with 10% slaked lime and the three groups with 20% slaked lime and 0.2%-0.6% water reducer, the particle crushing strength increases linearly with the increase of water reducer.

[0083] The groups with 20% slaked lime and 0.8% and 1.0% water reducer: the crushing strength of particles is significantly improved; the density continues to decrease, so the crushing strength is significantly improved;

[0084] 30% slaked lime dosage group: Regardless of the water reducer, the particle crushing strength is already high; there is a calcium hydroxide threshold, once the dosage is higher than the threshold, the carbonized particles can form a higher strength. Below this threshold, an appropriate amount of water reducer can be added to achieve the same effect.

[0085] The softening coefficient of soil particles carbonized with slaked lime is roughly distributed between 0.2 and 0.4, which proves that the addition of water reducer can improve the softening coefficient to a certain extent and the particles have a certain water resistance.

[0086] The above-mentioned specific implementation cases are used to illustrate the present invention and are only preferred embodiments of the present invention, rather than limiting the present invention. Any modifications, equivalent substitutions, improvements, etc. made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A preparation method of high-density and high-strength aggregate made from silty soil carbonization, characterized in that: The preparation method includes the following steps: S1. Dry the silty soil and control the moisture content; S2. Remove impurities from the dried silty soil and crush it; S3. Take the crushed silty soil as the base material, add a certain amount of slaked lime as a curing agent to the base material, and stir evenly to obtain the first mixture; S4. Add a water reducing agent to the first mixture to obtain the second mixture; S5. Add water to the second mixture, fully mix to obtain solidified soil, and compact and granulate it, controlling the mass of each particle; S6. Carry out a carbonization reaction on the compacted and granulated particles with carbon dioxide to obtain the carbonized soil finished product.

2. The preparation method of high-density and high-strength aggregate made from silty soil carbonization according to claim 1, characterized in that: In step S1, the moisture content is controlled to be not more than 5%.

3. The preparation method of high-density and high-strength aggregate made from silty soil carbonization according to claim 1, characterized in that: In step S2, the crushing particle size of the silty soil is controlled to be not more than 100 mesh.

4. The preparation method of high-density and high-strength aggregate made from silty soil carbonization according to claim 1, characterized in that: In step S3, the dry weight dosage of slaked lime is 20% - 30%.

5. The preparation method of high-density and high-strength aggregate made from silty soil carbonization according to claim 1, characterized in that: In step S3, the first mixture is polished until the fineness is not more than 100 mesh.

6. The preparation method of high-density and high-strength aggregate made from silty soil carbonization according to claim 1, characterized in that: In step S4, the water reducing agent is a polycarboxylate superplasticizer with a fineness not more than 100 mesh; the dosage of the water reducing agent is 0.2% - 1.0%.

7. The preparation method of high-density and high-strength aggregate made from silty soil carbonization according to claim 1 or 6, characterized in that: In step S4, the water reducing agent is a copolymer polymerized from acrylic acid, polyoxyethylene acrylate, and sodium methallylsulfonate as monomers.

8. The preparation method of high-density and high-strength aggregate made from silty soil carbonization according to claim 1, characterized in that: In step S5, the mass of the compacted and granulated particles is controlled to be 2.10g - 2.15g.

9. The preparation method of high-density and high-strength aggregate made from silty soil carbonization according to claim 1, characterized in that: In step S6, the conditions of the carbonization reaction are: temperature is 60°C, relative humidity is 60%, and the carbonization reaction time is 6h.

10. The high-density and high-strength aggregate prepared by the preparation method of high-density and high-strength aggregate made from silty soil carbonization according to any one of claims 1 - 9.

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