Cement-cementitious-material-free red-mud-based fully-regenerated stabilized macadam mixture suitable for road base and construction method of red-mud-based fully-regenerated stabilized macadam mixture

Abstract

The invention relates to the field of research and application of solid waste materials in road engineering, in particular to a cement-cementitious-material-free red-mud-based fully-regenerated stabilized macadam mixture suitable for a road base, which comprises the following components in parts by mass: 50-90 parts of building recycled aggregate, 3-15 parts of a red-mud-based cementing material and 2-8 parts of a water-based activator, the building recycled aggregate, the red-mud-based cementing material and the water-based activating agent are sequentially subjected to crushing, shaping, screening, proportioning design and mixing processes, and then the cement-cementitious-material-free red-mud-based fully-recycled stabilized macadam mixture suitable for the road base can be obtained. According to the red mud-based fully-regenerated stabilized macadam mixture without the cement gelling material, the cement gelling material with high energy consumption does not need to be added, and the mixture is completely composed of building solid waste and industrial solid waste, so that the problem of large-dosage utilization of building solid waste concrete and red mud is solved, and the red mud-based fully-regenerated stabilized macadam mixture is low in manufacturing cost, low in carbon and environmentally friendly; the social benefit and the economic benefit are obvious.

Description

Technical Field

[0001] The invention belongs to the research field of highway engineering technology, and specifically relates to a cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for a road base and a construction method thereof. Background Art

[0002] With the rapid development of my country's road traffic industry, by the end of 2023, the total mileage of my country's highways has reached 5.441 million kilometers. Influenced by the "strong base" design concept, more than 90% of my country's road bases use cement-stabilized gravel mixture, that is, concrete prepared with cement as binder and natural stone as aggregate. In recent years, with the implementation of the country's "dual carbon strategy", the application of high-energy cement and non-renewable stone resources has become increasingly restricted, and the price of natural aggregates has also gradually soared. Therefore, how to effectively replace cement-stabilized gravel mixture has become the focus of road research.

[0003] At present, domestic and foreign researchers are mainly concerned about the recycling of waste road concrete, that is, after the road milling concrete pavement materials are transported back to the processing plant, they are crushed by a crusher and added to the new cement-stabilized gravel mixture in a certain proportion. Due to the influence of performance, the general addition amount does not exceed 30%, which solves the problem of natural aggregate utilization to a certain extent. However, since the cementitious material used is cement, the shrinkage and temperature shrinkage caused by cement hydration are inevitable. Therefore, the crack disease problem of cement-stabilized gravel mixture has not been well solved. For this reason, researchers consider adding expansion agents to cement-stabilized gravel to compensate for the shrinkage of cement, and improving its crack resistance by adding flexible emulsified asphalt. However, the cementitious material used is still cement material, and shrinkage cracking disease is always unavoidable.

[0004] The existing cement-stabilized gravel base material is still mainly made of cement binder, which has the problems of high energy consumption, high pollution and shrinkage cracking. In addition, the recycled aggregate currently used only partially replaces the natural aggregate, and is not fully recycled. Therefore, it is particularly important to develop a red mud-based fully recycled stabilized gravel mixture suitable for road base without cement binder and its construction method. Summary of the invention

[0005] Based on the problems existing in the prior art, the present invention proposes a red mud-based fully recycled stabilized gravel mixture suitable for road base without cement binder and a construction method thereof, which can completely replace the cement binder and natural aggregate in the cement stabilized gravel mixture, and effectively solve the problem of the shortage of non-renewable natural aggregate resources, achieve the effect of energy conservation and emission reduction, and meet the current national low-carbon, environmental protection and sustainable development goals.

[0006] The technical solution adopted by the present invention is:

[0007] A cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for road base, comprising the following components in parts by mass:

[0008] 50-90 parts of building recycled aggregate;

[0009] 3-15 parts of red mud-based binder;

[0010] 2-8 parts of water-based activator.

[0011] Furthermore, the construction recycled aggregate is construction recycled coarse aggregate and construction recycled fine aggregate obtained from waste concrete and / or red bricks and / or ceramics from building demolition.

[0012] Furthermore, the construction recycled coarse aggregate includes the following particle size ranges: recycled coarse aggregate 1: 26.5mm-31.5mm; recycled coarse aggregate 2: 19mm-26.5mm; recycled coarse aggregate 3: 9.5mm-19mm; recycled coarse aggregate 4: 4.75mm-9.5mm.

[0013] Furthermore, the construction recycled fine aggregate includes the following particle size ranges: recycled fine aggregate 1: 2.36mm-4.75mm; recycled fine aggregate 2: 0.075mm-2.36mm.

[0014] Furthermore, the construction recycled aggregate is a skeleton-dense construction recycled mixture compounded by construction recycled coarse aggregate and construction recycled fine aggregate, and the gradation composition mass fraction is as follows:

[0015] 31.5mm:95%-100%;

[0016] 26.5mm:90%-100%;

[0017] 19.0mm:70%-95%;

[0018] 13.2mm:42%-85%;

[0019] 9.5mm: 25%-58%;

[0020] 4.75mm: 18%-32%;

[0021] 2.36mm: 10%-17%;

[0022] 0.6mm: 8%-12%;

[0023] 0.075mm:5%-10%.

[0024] Furthermore, the red mud-based binder includes nano-powdered active red mud, recycled micropowder, recycled red brick powder and calcium oxide powder.

[0025] Furthermore, the red mud-based binder comprises the following components in parts by weight:

[0026] 10-15 parts of nano powdery activated red mud;

[0027] Regeneration micro powder 10-20 parts;

[0028] 8-15 parts of recycled red brick powder;

[0029] 3-6 parts of calcium oxide powder.

[0030] Furthermore, the water-based activator comprises water, sodium hydroxide, sodium silicate, triethylenetetramine and low molecular weight polyamide.

[0031] Furthermore, the water-based activator comprises the following components in parts by mass:

[0032] 100 parts water;

[0033] Sodium hydroxide 5-10 parts;

[0034] 10-15 parts of sodium silicate;

[0035] 3-7 parts of triethylenetetramine;

[0036] 5-8 parts of low molecular weight polyamide.

[0037] In addition, the present invention also provides a construction method for a cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for a road base, comprising the following steps:

[0038] S1. Crushing construction waste concrete and / or red bricks and / or ceramics. Before crushing, the construction waste concrete and / or red bricks and / or ceramics are classified and screened to remove impurities therein, and then crushed by an impact crusher to obtain construction recycled coarse aggregate and construction recycled fine aggregate;

[0039] S2. shaping the recycled coarse aggregate and recycled fine aggregate in S1 by using a shaping machine, removing the mortar on the surface of the recycled coarse aggregate and recycled fine aggregate, and obtaining recycled coarse aggregate and recycled fine aggregate with an aspect ratio AR of 0.8-1.2;

[0040] S3. Use screening equipment to screen the construction recycled coarse aggregate and construction recycled fine aggregate in S2, and obtain recycled coarse aggregate 1: 26.5mm-31.5mm, recycled coarse aggregate 2: 19mm-26.5mm, recycled coarse aggregate 3: 9.5mm-19mm, recycled coarse aggregate 4: 4.75mm-9.5mm, recycled fine aggregate 1: 2.36mm-4.75mm, recycled fine aggregate 2: 0.075mm-2.36mm, and recycled micro powder and recycled red brick powder with a particle size of less than 0.075mm;

[0041] S4. Compounding the recycled coarse aggregate and recycled fine aggregate in S3 to obtain a dense skeleton recycled mixture with the following gradation composition mass fractions: 31.5mm: 95%-100%, 26.5mm: 90%-100%, 19.0mm: 70%-95%, 13.2mm: 42%-85%, 9.5mm: 25%-58%, 4.75mm: 18%-32%, 2.36mm: 10%-17%, 0.6mm: 8%-12%, 0.075mm: 5%-10%;

[0042] S5. Preparation of red mud-based binder, the nano-powdered active red mud 10-15 parts, regenerated powder 10-20 parts, regenerated red brick powder 8-15 parts and calcium oxide powder 3-6 parts were placed in a gas colloid mill for grinding to obtain a red mud-based binder;

[0043] S6. Prepare a water-based activator, 100 parts of water, 5-10 parts of sodium hydroxide, 10-15 parts of sodium silicate, 3-7 parts of triethylenetetramine and 5-8 parts of a low molecular weight polyamide are mixed and stirred to obtain a water-based activator;

[0044] S7. Use a mixing plant to evenly mix 50-90 parts of the skeleton-compacted building recycled mixture in S4, 3-15 parts of the red mud-based binder in S5 and 2-8 parts of the water-based activator in S6 to obtain a cement-free red mud-based fully recycled stable crushed stone mixture suitable for road base.

[0045] The beneficial effects produced by the present invention are as follows:

[0046] (1) The cement-free red mud-based fully recycled stabilized crushed stone mixture suitable for road base and its construction method of the present invention are low-carbon and environmentally friendly materials and technologies. Red mud-based cementitious materials that do not require high-temperature calcination are used to replace high-energy cement cementitious materials. They are low-carbon, energy-saving and environmentally friendly. Recycled coarse aggregate and recycled fine aggregate are used to 100% replace natural aggregates in cement-stabilized crushed stone mixtures, saving natural stone resources and having significant social and economic benefits.

[0047] (2) The strength of the red mud-based fully recycled stabilized crushed stone mixture without cement binder meets the index requirements of the road base mixture. The 7-day compressive strength meets the design strength requirements of the road base and subbase mixture. In addition, the strength is constantly increasing in the later period. The 28-day compressive strength is as high as 8.4MPa. No cement binder is used, and the 28-day shrinkage coefficient is less than 0.01%, which effectively solves the problem of cracking of the base mixture.

[0048] (3) While making high-value use of red mud and construction waste concrete for road base, it also effectively solves the problem of land occupation by industrial solid waste and construction solid waste storage.

[0049] Instruction Manual

[0050] Figure 1 This is the cement-free red mud-based fully recycled stabilized crushed stone mixture specimen suitable for road base in Example 3. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below in conjunction with the embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0052] Example 1

[0053] The first embodiment of the present invention is a cement-free cementitious material red mud-based fully recycled stabilized crushed stone mixture suitable for road base, which includes the following components in parts by weight: 50 parts of building recycled aggregate; 3 parts of red mud-based binder; and 2 parts of water-based activator.

[0054] Building recycled aggregates are building recycled coarse aggregates and building recycled fine aggregates obtained from waste concrete, red bricks and ceramics from building demolition.

[0055] The recycled coarse aggregate for construction includes the following particle size ranges: recycled coarse aggregate 1: 26.5mm-31.5mm; recycled coarse aggregate 2: 19mm-26.5mm; recycled coarse aggregate 3: 9.5mm-19mm; recycled coarse aggregate 4: 4.75mm-9.5mm.

[0056] The recycled fine aggregate for construction includes the following particle size ranges: recycled fine aggregate 1: 2.36mm-4.75mm; recycled fine aggregate 2: 0.075mm-2.36mm.

[0057] Building recycled aggregate is a skeleton-dense mixture made of recycled coarse aggregate and recycled fine aggregate. The gradation composition mass fractions are as follows: 31.5mm: 95%; 26.5mm: 90%; 19.0mm: 70%; 13.2mm: 42%; 9.5mm: 25%; 4.75mm: 18%; 2.36mm: 10%; 0.6mm: 8%; 0.075mm: 5%.

[0058] The red mud-based binder includes nano-powdered active red mud, regenerated micro powder, regenerated red brick powder and calcium oxide powder. The components by mass are: 10 parts of nano-powdered active red mud; 10 parts of regenerated micro powder; 8 parts of regenerated red brick powder; and 3 parts of calcium oxide powder.

[0059] The water-based activator includes water, sodium hydroxide, sodium silicate, triethylenetetramine and low molecular weight polyamide. The components by mass are: 100 parts of water; 5 parts of sodium hydroxide; 10 parts of sodium silicate; 3 parts of triethylenetetramine; and 5 parts of low molecular weight polyamide.

[0060] In order to verify the performance of the cement-free cementitious material red mud-based fully recycled stabilized crushed stone mixture suitable for the road base, the following steps were used to prepare the cement-free cementitious material red mud-based fully recycled stabilized crushed stone mixture suitable for the road base:

[0061] (1) crushing construction waste concrete, red bricks and ceramics. Before crushing, the construction waste concrete, red bricks and ceramics are classified and screened to remove impurities therein, and then crushed by an impact crusher to obtain construction recycled coarse aggregate and construction recycled fine aggregate;

[0062] (2) using a shaping machine to shape the recycled coarse aggregate and the recycled fine aggregate in (1), removing the mortar on the surface of the recycled coarse aggregate and the recycled fine aggregate, and obtaining the recycled coarse aggregate and the recycled fine aggregate with an aspect ratio AR of 0.8;

[0063] (3) using screening equipment to screen the recycled coarse aggregate and recycled fine aggregate in (2), and obtaining recycled coarse aggregate 1: 26.5 mm-31.5 mm; recycled coarse aggregate 2: 19 mm-26.5 mm; recycled coarse aggregate 3: 9.5 mm-19 mm; recycled coarse aggregate 4: 4.75 mm-9.5 mm; recycled fine aggregate 1: 2.36 mm-4.75 mm; recycled fine aggregate 2: 0.075 mm-2.36 mm, and recycled micro powder and recycled red brick powder with a particle size of less than 0.075 mm;

[0064] (4) The recycled coarse aggregate and the recycled fine aggregate in (3) are compounded to obtain a gradation composition mass fraction of a dense skeleton type recycled building mixture as follows: 31.5 mm: 95%, 26.5 mm: 90%, 19.0 mm: 70%, 13.2 mm: 42%, 9.5 mm: 25%, 4.75 mm: 18%, 2.36 mm: 10%, 0.6 mm: 8%, 0.075 mm: 5%;

[0065] (5) preparing a red mud-based binder by grinding 10 parts of nano-powdered active red mud, 10 parts of regenerated micropowder, 8 parts of regenerated red brick powder, and 3 parts of calcium oxide powder in a gas phase colloid mill to obtain a red mud-based binder;

[0066] (6) preparing a water-based activator by mixing and stirring 100 parts of water, 5 parts of sodium hydroxide, 10 parts of sodium silicate, 3 parts of triethylenetetramine, and 5 parts of low molecular weight polyamide to obtain a water-based activator;

[0067] (7) 50 parts of the skeleton-compacted building recycled mixture in (4), 3 parts of the red mud-based binder in (5) and 2 parts of the water-based activator in (6) are mixed evenly in a mixing plant to obtain a cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for road base. The performance test results are shown in Table 1.

[0068] Table 1 Test results of cement-free red mud-based fully recycled stabilized crushed stone mixture suitable for road base

[0069] Detection indicators Test Results Index requirements <![CDATA[Dry density / g / cm 3 > 2.244 ≥2.0 7d compressive strength / MPa 4.3 ≥3.5 28d compressive strength / MPa 6.7 / 28d shrinkage / % 0.004 ≤0.01

[0070] Example 2

[0071] The second embodiment of the present invention is a cement-free cementitious material red mud-based fully recycled stabilized crushed stone mixture suitable for road base, which includes the following components in parts by weight: 90 parts of building recycled aggregate; 15 parts of red mud-based binder; and 8 parts of water-based activator.

[0072] Building recycled aggregates are building recycled coarse aggregates and building recycled fine aggregates obtained from waste concrete and ceramics from building demolition.

[0073] The recycled coarse aggregate for construction includes the following particle size ranges: recycled coarse aggregate 1: 26.5mm-31.5mm; recycled coarse aggregate 2: 19mm-26.5mm; recycled coarse aggregate 3: 9.5mm-19mm; recycled coarse aggregate 4: 4.75mm-9.5mm.

[0074] The recycled fine aggregate for construction includes the following particle size ranges: recycled fine aggregate 1: 2.36mm-4.75mm; recycled fine aggregate 2: 0.075mm-2.36mm.

[0075] Building recycled aggregate is a skeleton-dense mixture made of recycled coarse aggregate and recycled fine aggregate. The gradation composition mass fractions are as follows: 31.5mm: 100%; 26.5mm: 100%; 19.0mm: 95%; 13.2mm: 85%; 9.5mm: 58%; 4.75mm: 32%; 2.36mm: 17%; 0.6mm: 12%; 0.075mm: 10%.

[0076] The red mud-based binder includes nano-powdered active red mud, regenerated micro powder, regenerated red brick powder and calcium oxide powder, and includes the following components by mass: 15 parts of nano-powdered active red mud, 20 parts of regenerated micro powder, 15 parts of regenerated red brick powder and 6 parts of calcium oxide powder.

[0077] The water-based activator comprises water, sodium hydroxide, sodium silicate, triethylenetetramine and low molecular weight polyamide, and comprises the following components in mass fractions: 100 parts of water, 10 parts of sodium hydroxide, 15 parts of sodium silicate, 7 parts of triethylenetetramine and 8 parts of low molecular weight polyamide.

[0078] In order to verify the performance of the cement-free cementitious material red mud-based fully recycled stabilized crushed stone mixture suitable for the road base, the following steps were used to prepare the cement-free cementitious material red mud-based fully recycled stabilized crushed stone mixture suitable for the road base:

[0079] (1) crushing construction waste concrete and ceramics, classifying and screening the construction waste concrete and ceramics before crushing, removing impurities therein, and then crushing them with an impact crusher to obtain construction recycled coarse aggregate and construction recycled fine aggregate;

[0080] (2) using a shaping machine to shape the recycled coarse aggregate and the recycled fine aggregate in (1), removing the mortar on the surface of the recycled coarse aggregate and the recycled fine aggregate, and obtaining the recycled coarse aggregate and the recycled fine aggregate with an aspect ratio AR of 1.2;

[0081] (3) using screening equipment to screen the recycled coarse aggregate and recycled fine aggregate in (2), and obtaining recycled coarse aggregate 1: 26.5 mm-31.5 mm; recycled coarse aggregate 2: 19 mm-26.5 mm; recycled coarse aggregate 3: 9.5 mm-19 mm; recycled coarse aggregate 4: 4.75 mm-9.5 mm; recycled fine aggregate 1: 2.36 mm-4.75 mm; recycled fine aggregate 2: 0.075 mm-2.36 mm, and recycled micro powder and recycled red brick powder with a particle size of less than 0.075 mm;

[0082] (4) The recycled coarse aggregate and the recycled fine aggregate in (3) are compounded to obtain the following gradation composition mass fractions of the dense skeleton type recycled building mixture: 31.5 mm: 100%, 26.5 mm: 100%, 19.0 mm: 95%, 13.2 mm: 85%, 9.5 mm: 58%, 4.75 mm: 32%, 2.36 mm: 17%, 0.6 mm: 12%, 0.075 mm: 10%;

[0083] (5) preparing a red mud-based binder by grinding 15 parts of nano-powdered active red mud, 20 parts of regenerated micro powder, 15 parts of regenerated red brick powder, and 6 parts of calcium oxide powder in a gas phase colloid mill to obtain a red mud-based binder;

[0084] (6) preparing a water-based activator by mixing and stirring 100 parts of water, 10 parts of sodium hydroxide, 15 parts of sodium silicate, 7 parts of triethylenetetramine, and 8 parts of low molecular weight polyamide to obtain a water-based activator;

[0085] (7) 90 parts of the skeleton-dense building recycled mixture in (4), 15 parts of the red mud-based binder in (5) and 8 parts of the water-based activator in (6) are mixed evenly in a mixing plant to obtain a cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for road base. The performance test results are shown in Table 2.

[0086] Table 2 Test results of red mud-based fully recycled stabilized crushed stone mixture suitable for road base without cement cementitious materials

[0087] Detection indicators Test Results Index requirements <![CDATA[Dry density / g / cm 3 > 2.315 ≥2.0 7d compressive strength / MPa 5.7 ≥3.5 28d compressive strength / MPa 7.9 / 28d shrinkage / % 0.008 ≤0.01

[0088] Example 3

[0089] The third embodiment of the present invention is a red mud-based fully recycled stabilized crushed stone mixture suitable for a road base layer, which comprises the following components in parts by weight: 87 parts of recycled building aggregate; 8 parts of red mud-based binder; and 5 parts of water-based activator.

[0090] Building recycled aggregates are building recycled coarse aggregates and building recycled fine aggregates obtained from waste concrete, red bricks and ceramics from building demolition.

[0091] The recycled coarse aggregate for construction includes the following particle size ranges: recycled coarse aggregate 1: 26.5mm-31.5mm; recycled coarse aggregate 2: 19mm-26.5mm; recycled coarse aggregate 3: 9.5mm-19mm; recycled coarse aggregate 4: 4.75mm-9.5mm.

[0092] The particle size ranges of recycled fine aggregate for construction are as follows: recycled fine aggregate 1: 2.36mm-4.75mm; recycled fine aggregate 2: 0.075mm-2.36mm.

[0093] Building recycled aggregate is a skeleton-dense building recycled mixture made by compounding building recycled coarse aggregate and building recycled fine aggregate. The mass fraction of each grade of aggregate is shown in Table 3.

[0094] Table 3 Proportion of recycled building materials for dense skeleton construction

[0095]

[0096] The red mud-based binder includes nano-powdered active red mud, recycled micropowder and recycled red brick powder, and includes the following components in parts by mass: 12 parts of nano-powdered active red mud, 15 parts of recycled micropowder, 9 parts of recycled red brick powder and 5 parts of calcium oxide powder.

[0097] The water-based activator includes water, sodium hydroxide, sodium silicate, triethylenetetramine and low molecular weight polyamide, and includes the following components in parts by weight: 100 parts of water, 5 parts of sodium hydroxide, 10 parts of sodium silicate, 4 parts of triethylenetetramine and 6 parts of low molecular weight polyamide.

[0098] In order to verify the performance of the cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for road base, the steps of Example 1 were used to prepare the cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for road base described in Example 3. The difference was that the components and proportions described in Example 3 were used.

[0099] In order to verify its road performance, shrinkage test and strength test were carried out on the red mud-based fully recycled stabilized crushed stone mixture without cement binder. The results are shown in Table 4.

[0100] Table 4 Performance test results of red mud-based fully recycled stabilized gravel mixture without cement binder

[0101] Detection indicators Test Results Index requirements 7d compressive strength / MPa 6.5 ≥3.5 28d compressive strength / MPa 8.4 / 28d shrinkage / % 0.005 ≤0.01

[0102] It can be found that the 7d compressive strength value of the cement-free red mud-based fully recycled stabilized gravel mixture prepared by the present invention meets the design strength requirements of the road base and subbase mixture, and the later strength is constantly increasing, and the 28d compressive strength reaches 8.4MPa; in addition, since no cement binder is used, the shrinkage coefficient is small, which effectively avoids the crack disease problem of the cement-stabilized gravel base.

[0103] Taking the example of verifying the application effect of the cement-free cementitious material red mud-based fully recycled stabilized crushed stone mixture suitable for the road base, it is prepared in combination with the actual project. The process is as follows:

[0104] ① Crushing construction waste concrete, red bricks and ceramics. Before crushing, the construction waste concrete, red bricks and ceramics are classified and screened to remove impurities, and then crushed with an impact crusher to obtain recycled aggregates that meet the particle size range of construction recycled coarse aggregate and construction recycled fine aggregate;

[0105] ② Use a shaping machine to shape the recycled coarse aggregate and the recycled fine aggregate, remove the mortar on the surface of the recycled coarse aggregate and the recycled fine aggregate, and obtain the recycled coarse aggregate and the recycled fine aggregate with an aspect ratio AR of 1.0;

[0106] ③ Use screening equipment to screen the construction recycled coarse aggregate and construction recycled fine aggregate, and obtain recycled coarse aggregate 1: 26.5mm-31.5mm, recycled coarse aggregate 2: 19mm-26.5mm, recycled coarse aggregate 3: 9.5mm-19mm, recycled coarse aggregate 4: 4.75mm-9.5mm, recycled fine aggregate 1: 2.36mm-4.75mm, recycled fine aggregate 2: 0.075mm-2.36mm, and recycled micro powder and recycled red brick powder with a particle size of less than 0.075mm;

[0107] ④ Compound the recycled coarse aggregate and the recycled fine aggregate to obtain a skeleton-dense recycled mixture that meets the mass fraction in Table 3;

[0108] ⑤ Prepare red mud-based binder: 12 parts of nano-powdered active red mud, 15 parts of regenerated micro powder, 9 parts of regenerated red brick powder and 5 parts of calcium oxide powder are put into a gas phase colloid mill for grinding to obtain red mud-based binder;

[0109] ⑥ Prepare a water-based activator by mixing and stirring 100 parts of water, 5 parts of sodium hydroxide, 10 parts of sodium silicate, 4 parts of triethylenetetramine and 6 parts of low molecular weight polyamide to obtain a water-based activator;

[0110] ⑦ Use a mixing plant to evenly mix 87 parts of building recycled aggregate, 8 parts of red mud-based binder and 5 parts of water-based activator to obtain a cement-free red mud-based fully recycled stabilized crushed stone mixture suitable for road base, and pave it in the road base.

[0111] Finally, core sampling was carried out after curing for 7 and 28 days under natural conditions. The performance results of the red mud-based fully recycled stabilized crushed stone mixture suitable for road base are shown in Table 5. The tested specimens are as follows Figure 1 shown.

[0112] Table 5 Test results of red mud-based fully recycled stabilized crushed stone mixture suitable for road base without cement cementitious materials

[0113] Detection indicators Test Results Index requirements <![CDATA[Dry density / g / cm 3 > 2.358 ≥2.0 Compaction degree / % 98.5 ≥97 7d compressive strength / MPa 6.3 ≥5 28d compressive strength / MPa 7.8 / Flatness 1.34mm ≤2 / mm

[0114] Judging from the implementation results of the test section project, the red mud-based fully recycled stabilized crushed stone mixture of the cement-free cementitious material suitable for road base of the present invention adopts red mud-based binder materials instead of cement, and adopts construction solid waste materials to completely replace natural aggregates. The obtained road base mixture has excellent performance, and the strength, dry density, compaction degree and flatness can all meet the technical index requirements, and the application effect is good; in addition, by utilizing industrial solid waste red mud and construction solid waste concrete, the accumulation of these two types of waste materials, occupying land resources and the impact on the environment are greatly reduced, which has significant social, economic and environmental benefits.

[0115] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A cement-free red mud-based fully recycled stable crushed stone mixture suitable for road base, characterized in that: The composition includes the following components in parts by weight: 50-90 parts of building recycled aggregate; 3-15 parts of red mud-based binder; 2-8 parts of water-based activator.

2. The cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for road base according to claim 1, characterized in that: The building recycled aggregate is building recycled coarse aggregate and building recycled fine aggregate obtained from waste concrete and / or red bricks and / or ceramics from building demolition.

3. The cement-free red mud-based fully recycled stable crushed stone mixture suitable for road base according to claim 2, characterized in that: The recycled coarse aggregate for construction includes the following particle size ranges: recycled coarse aggregate 1: 26.5mm-31.5mm; recycled coarse aggregate 2: 19mm-26.5mm; recycled coarse aggregate 3: 9.5mm-19mm; recycled coarse aggregate 4: 4.75mm-9.5mm.

4. The cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for road base according to claim 2, characterized in that: The construction recycled fine aggregate includes the following particle size ranges: recycled fine aggregate 1: 2.36mm-4.75mm; recycled fine aggregate 2: 0.075mm-2.36mm.

5. The cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for road base according to claim 1, characterized in that: The building recycled aggregate is a skeleton-dense building recycled mixture compounded by building recycled coarse aggregate and building recycled fine aggregate, and the gradation composition mass fraction is as follows: 31.5mm:95%-100%; 26.5mm:90%-100%; 19.0mm:70%-95%; 13.2mm:42%-85%; 9.5mm: 25%-58%; 4.75mm: 18%-32%; 2.36mm: 10%-17%; 0.6mm: 8%-12%; 0.075mm:5%-10%.

6. The cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for road base according to claim 1, characterized in that: The red mud-based binder comprises nanometer powdery active red mud, regenerated micro powder, regenerated red brick powder and calcium oxide powder.

7. The cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for road base according to claim 6, characterized in that: The red mud-based binder comprises the following components in parts by weight: 10-15 parts of nano powdery activated red mud; Regeneration micro powder 10-20 parts; 8-15 parts of recycled red brick powder; 3-6 parts of calcium oxide powder.

8. The cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for road base according to claim 1, characterized in that: The water-based activator comprises water, sodium hydroxide, sodium silicate, triethylenetetramine and low molecular weight polyamide.

9. The cement-free cementitious material red mud-based fully recycled stable crushed stone mixture suitable for road base according to claim 8, characterized in that: The water-based activator comprises the following components in parts by mass: 100 parts water; Sodium hydroxide 5-10 parts; Sodium silicate 10-15 parts; 3-7 parts of triethylenetetramine; 5-8 parts of low molecular weight polyamide.

10. The construction method of the cement-free red mud-based fully recycled stable crushed stone mixture suitable for road base according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Crushing construction waste concrete and / or red bricks and / or ceramics. Before crushing, the construction waste concrete and / or red bricks and / or ceramics are classified and screened to remove impurities therein, and then crushed by an impact crusher to obtain construction recycled coarse aggregate and construction recycled fine aggregate; S2. shaping the recycled coarse aggregate and recycled fine aggregate in S1 by using a shaping machine, removing the mortar on the surface of the recycled coarse aggregate and recycled fine aggregate, and obtaining recycled coarse aggregate and recycled fine aggregate with an aspect ratio AR of 0.8-1.2; S3. Use screening equipment to screen the construction recycled coarse aggregate and construction recycled fine aggregate in S2, and obtain recycled coarse aggregate 1: 26.5mm-31.5mm, recycled coarse aggregate 2: 19mm-26.5mm, recycled coarse aggregate 3: 9.5mm-19mm, recycled coarse aggregate 4: 4.75mm-9.5mm, recycled fine aggregate 1: 2.36mm-4.75mm, recycled fine aggregate 2: 0.075mm-2.36mm, and recycled micro powder and recycled red brick powder with a particle size of less than 0.075mm; S4. Compounding the recycled coarse aggregate and recycled fine aggregate in S3 to obtain a dense skeleton recycled mixture with the following gradation composition mass fractions: 31.5mm: 95%-100%, 26.5mm: 90%-100%, 19.0mm: 70%-95%, 13.2mm: 42%-85%, 9.5mm: 25%-58%, 4.75mm: 18%-32%, 2.36mm: 10%-17%, 0.6mm: 8%-12%, 0.075mm: 5%-10%; S5. Preparation of red mud-based binder, the nano-powdered active red mud 10-15 parts, regenerated powder 10-20 parts, regenerated red brick powder 8-15 parts and calcium oxide powder 3-6 parts were placed in a gas colloid mill for grinding to obtain a red mud-based binder; S6. Prepare a water-based activator, 100 parts of water, 5-10 parts of sodium hydroxide, 10-15 parts of sodium silicate, 3-7 parts of triethylenetetramine and 5-8 parts of a low molecular weight polyamide are mixed and stirred to obtain a water-based activator; S7. Use a mixing plant to evenly mix 50-90 parts of the skeleton-compacted building recycled mixture in S4, 3-15 parts of the red mud-based binder in S5 and 2-8 parts of the water-based activator in S6 to obtain a cement-free red mud-based fully recycled stable crushed stone mixture suitable for road base.

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