A method for recycling cement-stabilized crushed stone milling material based on flow solidification

Abstract

This invention discloses a method for recycling cement-stabilized crushed stone milled material based on flow curing, comprising: milling the surface layer of an old road to remove the surface layer; milling the cement-stabilized crushed stone layer of the old road to obtain cement-stabilized crushed stone milled material; mixing natural soil, sand, and cement-stabilized crushed stone milled material, adding a curing agent solution, and then adding water to adjust the water-to-solid ratio to 0.9–1.1 to obtain recycled material; using the recycled material to pour the road surface to reach the design elevation, and completing the recycling of cement-stabilized crushed stone milled material after 10–14 days of curing. This method not only enables the reuse of cement-stabilized crushed stone milled material but also improves the flowability of the recycled material and utilizes the curing effect of the curing agent solution to achieve overall strength in the recycled material.

Description

Technical Field

[0001] This invention belongs to the field of road engineering construction technology, specifically relating to a method for recycling cement-stabilized crushed stone milling material based on flow solidification. Background Technology

[0002] Currently, the total length of highways in China has reached 5.2807 million kilometers, and the country is in a stage of "equal emphasis on construction and maintenance." The demand for road base filling materials in road reconstruction and expansion projects is enormous. Using stone for filling makes it difficult to guarantee the source of the materials and will cause irreversible damage to resources, the environment, and the ecosystem.

[0003] In-situ cold recycling technology is currently the main technical means for utilizing road milling materials in road reconstruction, expansion and major repair projects. It involves using a cold recycling machine to mill and crush the old asphalt pavement and base course at room temperature, determining whether new graded aggregates need to be added by screening the original aggregates, adding a certain proportion of stabilizer and water and mixing thoroughly, and finally paving and compacting it as a new base course.

[0004] However, since the fillers added during in-situ cold recycling are mainly in the form of cement and mineral powder, and cement and mineral powder are primarily in powder form, when the fillers are spread on the surface of the aggregate milled from the old road surface during on-site construction, natural wind or the airflow from passing construction vehicles can easily stir up the cement. When the wind is strong, this can easily generate dust, affecting the surrounding environment. Secondly, due to varying road surface damage, the gradation of the recycled material milled from the old road surface will also differ significantly. Furthermore, the current cold recycling process directly spreads the aggregate on the surface of the old road surface and then uses a cold recycling machine for recycling. The high rotation speed of the recycling machine causes some of the added aggregate to be broken, resulting in a finer gradation in the field compared to the cold recycled mixture gradation determined by laboratory experiments. Furthermore, during the cold recycling process, the retracting part of the recycling machine's cutter head is constantly rotating, giving the aggregate more room to move as the box is lifted. As a result, coarse and fine aggregates will separate, leading to lateral segregation of the aggregate. Also, due to the different degrees of damage to the old road surface, the gradation of the milled recycled material is different, resulting in different optimal water usage. It is difficult to adjust the water usage according to actual needs during the cold recycling process.

[0005] Therefore, there is an urgent need for a method for recycling cement-stabilized crushed stone milling material based on flow curing that can avoid dust during construction and allow the milled material to be recycled and reused for repair or expansion based on the actual road surface conditions. Summary of the Invention

[0006] The object of the present invention is to overcome at least the aforementioned defects and to provide advantages that will be described later.

[0007] To achieve these objectives and other advantages of the present invention, a method for recycling cement-stabilized crushed stone milling material based on flow solidification is provided, comprising:

[0008] The surface layer of the old road surface is removed by milling.

[0009] The cement-stabilized crushed stone layer of the old road surface is milled to obtain cement-stabilized crushed stone milled material.

[0010] Natural soil, sand, and cement-stabilized crushed stone milling material are mixed together, a curing agent solution is added, and water is added to adjust the water-to-solid ratio to 0.9–1.1 to obtain recycled material.

[0011] The recycled material is used to pour the road surface to the design elevation, and after 10 to 14 days of curing, the recycling of cement-stabilized crushed stone milling material is completed.

[0012] In the above scheme, firstly, the method for recycling cement-stabilized crushed stone milling material based on flow curing of the present invention, by first removing the base layer of the old road surface and then milling the cement-stabilized crushed stone layer, can better recycle the cement-stabilized crushed stone milling material of the cement-stabilized crushed stone layer.

[0013] Secondly, the present invention's method for recycling cement-stabilized crushed stone milling material based on flow solidification involves mixing cement-stabilized crushed stone milling material with soil and sand in a specific ratio to form recycled material with a water-to-solid ratio of 0.9 to 1.1. This recycled material is then used for road surface pouring, effectively avoiding dust problems. Simultaneously, the recycled cement-stabilized crushed stone milling material can be re-graded based on the actual amount recovered, resulting in a more rational proportion of the recycled material and facilitating the formation of a stable structure with overall strength with the old road surface after pouring.

[0014] Furthermore, the method for recycling cement-stabilized crushed stone milling material based on flow curing of the present invention uses a curing agent solution for preparation, so that the three-dimensional network structure generated by the interaction of the prepared recycled material enhances the mechanical properties of the recycled material, improves the fluidity of the recycled material, and facilitates casting construction using a remote pump.

[0015] Preferably, the mass ratio of the natural soil, sand, and cement-stabilized crushed stone milling material is 160:320:1120.

[0016] Preferably, the mixing time of the natural soil, sand and cement-stabilized crushed stone milling material is not less than 3 minutes.

[0017] Preferably, the mass ratio of the amount of curing agent solution added to the total amount of natural soil, sand and cement-stabilized crushed stone milling material is 200-260:1160.

[0018] Preferably, the water-cement ratio of the curing agent solution is 0.4 to 0.5.

[0019] Preferably, the mass ratio of the natural soil, sand, cement-stabilized crushed stone milling material and curing agent solution is 160:320:1120:220.

[0020] Preferably, the mass ratio of the natural soil, sand, cement-stabilized crushed stone milling material, and curing agent solution is 160:320:1120:260.

[0021] Advantages of this invention:

[0022] First, the method for recycling cement-stabilized crushed stone milling material based on flow curing of the present invention improves the fluidity of the recycled material by adjusting the gradation of the cement-stabilized crushed stone milling material, and then utilizes the curing effect of the curing agent solution to make the recycled material form an integral strength, so that the cement-stabilized crushed stone milling material can be directly used for road base courses, saving engineering costs.

[0023] Secondly, the method for recycling cement-stabilized crushed stone milling material based on flow solidification of the present invention reduces the construction control difficulty in the cold recycling of cement-stabilized crushed stone milling material, improves the construction working environment, and the recycled material can be directly cast into shape, eliminating the cumbersome process of layered paving and layered compaction in road base construction, making the construction process simpler and greatly shortening the construction cycle; at the same time, it also solves the problem of controlling the compaction degree of road base.

[0024] Furthermore, the method for recycling cement-stabilized crushed stone milling material based on flow curing of the present invention can meet the technical performance requirements of roads of various grades by adjusting the amount of curing agent solution added and the water-solid ratio of the recycled material; the recycled material has a low permeability coefficient, avoiding water damage to the road, and has excellent anti-freezing performance, which can significantly improve the road damage caused by low temperature frost heave. Detailed Implementation

[0025] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0026] Example 1

[0027] A method for recycling cement-stabilized crushed stone milling material based on flow solidification includes:

[0028] Step 1: Mill the surface layer of the old road surface to remove the old surface layer.

[0029] Step 2: Mill the cement-stabilized crushed stone layer of the old road surface to obtain cement-stabilized crushed stone milled material.

[0030] Step 3: Prepare the curing agent solution with a water-cement ratio of 0.4 to 0.5.

[0031] Step 4: Mix natural soil, sand, cement-stabilized crushed stone milling material and the curing agent solution prepared in Step 3 according to a mass ratio of 160:320:1120:200. Then add water to adjust the water-to-solid ratio to 0.9 to obtain recycled material.

[0032] Step 5: Use recycled material to pour the road surface to reach the design elevation. After 10 to 14 days of curing, the recycling of cement-stabilized crushed stone milling material is completed.

[0033] The road surface is poured using a concrete pump truck along a pipeline, with the entire pour achieved by moving the pouring nozzle. After pouring, manual vibration and leveling are performed to the required design elevation. Mechanical disturbance is avoided during the curing period.

[0034] Example 2

[0035] A method for recycling cement-stabilized crushed stone milling material based on flow solidification includes:

[0036] Step 1: Mill the surface layer of the old road surface to remove the old surface layer.

[0037] Step 2: Mill the cement-stabilized crushed stone layer of the old road surface to obtain cement-stabilized crushed stone milled material.

[0038] Step 3: Prepare the curing agent solution with a water-cement ratio of 0.4 to 0.5.

[0039] Step 4: Mix natural soil, sand, cement-stabilized crushed stone milling material and the curing agent solution prepared in Step 3 according to the mass ratio of 160:320:1120:220. Then add water to adjust the water-solid ratio to 0.9 to obtain recycled material.

[0040] Step 5: Use recycled material to pour the road surface to reach the design elevation. After 10 to 14 days of curing, the recycling of cement-stabilized crushed stone milling material is completed.

[0041] Example 3

[0042] A method for recycling cement-stabilized crushed stone milling material based on flow solidification includes:

[0043] Step 1: Mill the surface layer of the old road surface to remove the old surface layer.

[0044] Step 2: Mill the cement-stabilized crushed stone layer of the old road surface to obtain cement-stabilized crushed stone milled material.

[0045] Step 3: Prepare the curing agent solution with a water-cement ratio of 0.4 to 0.5.

[0046] Step 4: Mix natural soil, sand, cement-stabilized crushed stone milling material and the curing agent solution prepared in Step 3 according to the mass ratio of 160:320:1120:220. Then add water to adjust the water-solid ratio to 1.0 to obtain recycled material.

[0047] Step 5: Use recycled material to pour the road surface to reach the design elevation. After 10 to 14 days of curing, the recycling of cement-stabilized crushed stone milling material is completed.

[0048] Example 4

[0049] A method for recycling cement-stabilized crushed stone milling material based on flow solidification includes:

[0050] Step 1: Mill the surface layer of the old road surface to remove the old surface layer.

[0051] Step 2: Mill the cement-stabilized crushed stone layer of the old road surface to obtain cement-stabilized crushed stone milled material.

[0052] Step 3: Prepare the curing agent solution with a water-cement ratio of 0.4 to 0.5.

[0053] Step 4: Mix natural soil, sand, cement-stabilized crushed stone milling material and the curing agent solution prepared in Step 3 according to the mass ratio of 160:320:1120:260, and then add water to adjust the water-solid ratio to 1.0 to obtain recycled material.

[0054] Step 5: Use recycled material to pour the road surface to reach the design elevation. After 10 to 14 days of curing, the recycling of cement-stabilized crushed stone milling material is completed.

[0055] Example 5

[0056] A method for recycling cement-stabilized crushed stone milling material based on flow solidification includes:

[0057] Step 1: Mill the surface layer of the old road surface to remove the old surface layer.

[0058] Step 2: Mill the cement-stabilized crushed stone layer of the old road surface to obtain cement-stabilized crushed stone milled material.

[0059] Step 3: Prepare the curing agent solution with a water-cement ratio of 0.4 to 0.5.

[0060] Step 4: Mix natural soil, sand, cement-stabilized crushed stone milling material and the curing agent solution prepared in Step 3 according to the mass ratio of 160:320:1120:260. Then add water to adjust the water-solid ratio to 1.1 to obtain recycled material.

[0061] Step 5: Use recycled material to pour the road surface to reach the design elevation. After 10 to 14 days of curing, the recycling of cement-stabilized crushed stone milling material is completed.

[0062] Example 6

[0063] A method for recycling cement-stabilized crushed stone milling material based on flow solidification includes:

[0064] Step 1: Mill the surface layer of the old road surface to remove the old surface layer.

[0065] Step 2: Mill the cement-stabilized crushed stone layer of the old road surface to obtain cement-stabilized crushed stone milled material.

[0066] Step 3: Prepare the curing agent solution with a water-cement ratio of 0.4 to 0.5.

[0067] Step 4: Mix natural soil, sand, cement-stabilized crushed stone milling material and the curing agent solution prepared in Step 3 according to the mass ratio of 160:320:1120:260. Then add water to adjust the water-solid ratio to 1.1 to obtain recycled material.

[0068] Step 5: Use recycled material to pour the road surface to reach the design elevation. After 10 to 14 days of curing, the recycling of cement-stabilized crushed stone milling material is completed.

[0069] Step 6: After the maintenance is completed, conduct a quality inspection of the road base. Test the unconfined compressive strength of the recycled material by core sampling, and then test the deflection value of the roadbed on site.

[0070] Step 7: After all the indicators of the recycled material meet the design requirements, lay an asphalt concrete layer on the cured road surface to complete the construction of the old road surface.

[0071] Indicator Testing:

[0072] The slump of the recycled materials obtained in Examples 1 to 5 were measured, and the compressive strength and surface deflection of the pavement in each example were measured after curing. The measurement was carried out by core sampling method, and the test standard of JTG-F20-2015 Technical Specifications for Construction of Highway Pavement Base Course was used. The results are shown in Table 1.

[0073] Table 1:

[0074] project Slump of recycled material / mm pavement compressive strength / MPa Surface deflection value / 0.1mm Example 1 125 5.5 32 Example 2 115 6.3 22 Example 3 145 5.8 27 Example 4 135 8.5 16 Example 5 160 7.8 18

[0075] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Other modifications can be readily implemented by those skilled in the art. Therefore, the present invention is not limited to the specific details without departing from the general concept defined by the claims and their equivalents.

Claims

1. A method for recycling cement-stabilized macadam milled material based on flow curing, characterized in that, The application relates to a cement stabilized macadam regenerating method. The method comprises the following steps: a milling construction is carried out on the surface layer of an old road to remove the surface layer of the old road; a milling construction is carried out on the cement stabilized macadam layer of the old road to obtain cement stabilized macadam milling materials; natural soil materials, sand and the cement stabilized macadam milling materials are mixed, a solidifying agent solution is added, and water is added to adjust the water-solid ratio to 0.9-1.1, so that regenerated materials are obtained; the regenerated materials are used to pour the road to reach the design elevation, and the cement stabilized macadam milling material regenerating is completed after 10-14 days of maintenance; the mass ratio of the natural soil materials, the sand and the cement stabilized macadam milling materials is 160:320:1120; the mixing time of the natural soil materials, the sand and the cement stabilized macadam milling materials is not less than 3 minutes; 2. The flow-curing-based cement-stabilized macadam milled material recycling method according to Claim 1, characterized by, the mass ratio of the natural soil materials, the sand, the cement stabilized macadam milling materials and the solidifying agent solution is 160:320:1120:220; or the mass ratio of the natural soil materials, the sand, the cement stabilized macadam milling materials and the solidifying agent solution is 160:320:1120:260; or the mass ratio of the natural soil materials, the sand, the cement stabilized macadam milling materials and the solidifying agent solution is 160:320:1120:

200. The water-cement ratio of the solidifying agent solution is 0.4-0.5.