Anti-reflection crack cement pavement reconstruction and expansion pavement structure

Abstract

The utility model discloses a cement pavement reconstruction and expansion pavement structure capable of resisting reflection cracks, which belongs to the technical field of pavement structures and comprises a bottom layer, an upper layer and a lower layer. The flexible base layer comprises a water-based-organic polymer stabilized macadam layer laid on the old road structure layer, and tack coat oil is laid between the water-based-organic polymer stabilized macadam layer and the old road structure layer; the upper layer comprises an asphalt surface layer, and the asphalt surface layer is laid on the water-based-organic polymer stabilized macadam layer. According to the utility model, the bearing capacity and anti-rutting capacity of the reconstructed and expanded road structure can be ensured, the reflection crack resistance of the pavement structure is improved, the thickness of the asphalt surface layer can be effectively reduced, the asphalt consumption is reduced, and good economic benefits and environmental protection benefits are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of pavement structures, in particular to a cement pavement reconstruction and expansion structure capable of resisting reflective cracks. Background Art

[0002] With the in-depth development of my country's social economy and urbanization, the cement concrete pavement structure built in the early stage has been seriously damaged and cannot adapt to the rapid development of traffic volume. Direct paving or milling paving is the main measure to improve the service performance of old roads and extend their life. In the design of road reconstruction and expansion, according to the structural performance evaluation results of existing roads, direct paving or milling and paving can be adopted. The anti-reflection effect can be improved by laying geogrids or fiber cloth, but the effect of geotextiles will decline with the aging of the material itself. Multi-layer paving can effectively improve the bearing capacity of the pavement structure. Semi-rigid base layer + asphalt surface layer is usually used as the pavement structure of the paved layer. However, this kind of paved pavement structure will have problems such as incomplete treatment of old road diseases, secondary expansion of existing cracks, thermal shrinkage and dry shrinkage of the paved water-stable base layer leading to the development of reflective cracks, resulting in unsatisfactory reconstruction and expansion effects. Using graded crushed stone as the base layer can prevent the expansion of reflective cracks. The asphalt layer is laid on top. In this case, the asphalt layer needs to be very thick, which increases the amount of asphalt used. Asphalt materials are scarce and non-renewable resources. They consume a lot of energy and produce more polluting gases during the production process, making it difficult to promote flexible base layer paving structures.

[0003] Therefore, a cement pavement reconstruction and expansion pavement structure with anti-reflective cracking is proposed. Utility Model Content

[0004] The utility model aims to provide a cement pavement reconstruction and expansion pavement structure with anti-reflective cracking, aiming to solve or improve at least one of the above-mentioned technical problems.

[0005] To achieve the above-mentioned purpose, the utility model provides the following solution: The utility model provides a cement pavement reconstruction and expansion pavement structure with anti-reflective cracking, comprising:

[0006] A bottom layer, the bottom layer comprising an old road structure layer;

[0007] A flexible base layer, the flexible base layer comprising a water-based-organic polymer stabilized gravel layer laid on the old road structure layer, and an adhesive layer of oil is laid between the water-based-organic polymer stabilized gravel layer and the old road structure layer;

[0008] The upper layer comprises an asphalt surface layer, and the asphalt surface layer is laid on the water-based-organic polymer stabilized crushed stone layer.

[0009] Preferably, a cement stabilized gravel layer is also laid between the tack coat oil and the water-based-organic polymer stabilized gravel layer.

[0010] Preferably, the tack coat oil is emulsified asphalt modified by SBR composite binder.

[0011] Preferably, the asphalt surface layer includes a first asphalt layer, a second asphalt layer, and a third asphalt layer laid in sequence from top to bottom, the first asphalt layer is a modified asphalt mixture, and the second asphalt layer and the third asphalt layer are both ordinary asphalt mixtures.

[0012] Preferably, the total thickness of the asphalt surface layer is 10cm-18cm.

[0013] Preferably, the thickness of the water-based-organic polymer stabilized gravel layer is 18 cm-24 cm.

[0014] Preferably, the thickness of the cement-stabilized gravel layer is 18 cm-25 cm.

[0015] The utility model discloses the following technical effects: by adopting water-based-organic polymer stabilized crushed stone as the flexible base layer for additional paving, the small deformation and low temperature sensitivity of the water-based-organic polymer stabilized crushed stone layer are fully utilized to ensure the bearing capacity and anti-rutting ability of the modified and expanded road structure, and it has a lower temperature shrinkage deformation coefficient, which can effectively prevent the upward propagation of cracks in the lower structure and improve the anti-reflective crack performance of the pavement structure. At the same time, it can effectively reduce the thickness of the asphalt surface layer and reduce the amount of asphalt used, and has good economic and environmental benefits; by using bonding oil, the additional flexible base layer is well bonded to the old road structure layer, making it a more stable overall structure, thereby improving the performance of the pavement structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0017] Figure 1 It is a structural schematic diagram of Example 1;

[0018] Figure 2 This is a schematic diagram of the structure of Example 2.

[0019] In the figure: 1. Asphalt surface layer; 2. Water-based-organic polymer stabilized gravel layer; 3. Tack coat oil; 4. Old road structure layer; 5. Cement stabilized gravel layer. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0022] Example 1

[0023] Reference Figure 1 The utility model provides a cement pavement reconstruction and expansion pavement structure with anti-reflective cracking, comprising:

[0024] The bottom layer includes the old road structure layer 4;

[0025] The flexible base layer comprises a water-based-organic polymer stabilized gravel layer 2 laid on an old road structure layer 4, and an adhesive layer 3 is laid between the water-based-organic polymer stabilized gravel layer 2 and the old road structure layer 4;

[0026] The water-based-organic polymer stabilized gravel layer 2 is composed of water-based-organic polymer, water, coarse aggregate, fine aggregate and mineral powder; the water-based-organic polymer is a new type of high molecular weight resin polymer road stabilizer, which has the advantages of being environmentally friendly, non-toxic and harmless; the water-based-organic polymer is dissolved in water to form a solution, which is mixed with the aggregate at room temperature. As the water evaporates, the polymer and the aggregate surface form a dense polymer film with good bonding properties; as the water is lost, the strength gradually increases; the water-based-organic polymer stabilized gravel layer 2 is different from the semi-rigid base layer. The polymer material is less affected by temperature, and the pavement structure has good mechanical properties and deformation coordination, which can effectively reduce the rutting of the pavement structure; at the same time, the temperature shrinkage coefficient of the water-based-organic polymer stabilized gravel layer 2 is lower than that of cement stabilized gravel, and the deformation caused by temperature changes is smaller, which can effectively prevent the occurrence of reflective cracks;

[0027] The upper layer includes an asphalt surface layer 1, and the asphalt surface layer 1 is laid on a water-based-organic polymer stabilized crushed stone layer 2;

[0028] Adhesive layer oil 3 is emulsified asphalt modified by SBR composite binder to improve the adhesion;

[0029] The asphalt surface layer 1 includes a first asphalt layer, a second asphalt layer, and a third asphalt layer which are laid in sequence from top to bottom. The first asphalt layer is a modified asphalt mixture, and the second asphalt layer and the third asphalt layer are both ordinary asphalt mixtures.

[0030] Modified asphalt has good oxidation resistance and better durability, which can effectively improve the life of the road surface and reduce the cost of road maintenance; ordinary asphalt is low in cost and easy to construct; by combining modified asphalt mixture with ordinary asphalt mixture, the durability of the asphalt surface layer 1 can be improved while reducing the cost;

[0031] The total thickness of the asphalt surface layer 1 is 10cm-18cm;

[0032] The thickness of the water-based-organic polymer stabilized gravel layer 2 is 18 cm to 24 cm;

[0033] When the load-bearing capacity of the old road structure layer 4 is assessed to be good and does not require milling, the additional pavement structure layers are asphalt surface layer 1, water-based-organic polymer stabilized crushed stone layer 2, and tack coat 3 from top to bottom. The tack coat 3 is laid on the surface of the old road structure layer 4.

[0034] The first asphalt layer in the asphalt surface layer 1 is made of SBS-AC13, the second asphalt layer is made of AC20, and the third asphalt layer is made of AC25;

[0035] In this embodiment, the pavement structure materials and thicknesses are as follows: the asphalt surface layer 1 is 4cmSBS-AC13+5cmAC20+6cmAC25; the water-based-organic polymer stabilized gravel layer 2 is 18cm thick; a tack coat 3 is spread between the old road structure layer 4 and the water-based-organic polymer stabilized gravel layer 2; the tack coat 3 uses emulsified asphalt modified with SBR composite binder, and the dosage is 0.4kg / m 2 , ensuring the bonding performance with the old road structure layer 4;

[0036] The water-based-organic polymer stabilized gravel layer 2 is composed of water-based-organic polymer, water, coarse aggregate, fine aggregate and mineral powder; the water-based-organic polymer emulsion accounts for 0.5% of the total weight of the aggregate, the optimal water content is 4.06%, the proportion of mineral powder is 5%, and the design results of different particle size gradations are shown in Table 1:

[0037] Table 1 Water-based-organic polymer stabilized crushed stone gradation design results

[0038] Screen size (mm) 7.5 31.5 26.5 19 16 13.2 9.5 4.75 2.36 0.6 0.3 0.075 Pass rate (%) 100.0 97.3 91.3 77.4 69.5 59.4 55.0 38.3 23.9 12.0 8.3 5.7 Required range (%) 100.0 90～100 79～95 60～85 53～80 48～74 40～65 25～50 18～40 9～25 6～20 0～7

[0039] The crushing value, needle-like particle content, Los Angeles abrasion value, and firmness of coarse aggregate, and the sand equivalent, firmness, and plasticity index of fine aggregate should be tested using the "Highway Engineering Aggregate Test Code" (JTGE42) and "Highway Geotechnical Test Code" (JTGE40). The test results and property requirements are shown in Table 2:

[0040] Table 2 Aggregate property requirements

[0041]

[0042] In the water-based organic polymer used in this embodiment, the styrene content is 10%-12%, the polymethacrylate content is 5%-10%, the silicone resin content is 1.5%-3.5%, the other ester content is 57.5%-70%, the lubricant content is 5%-6%, the catalyst content is 0.5%-1%, and the solid content of the above components is 28.5%-31.5%. The specific technical index requirements and test results are shown in Table 3:

[0043] Table 3 Technical index requirements of water-based organic polymers

[0044] Test items pH Solid content (%) Viscosity (cps) Water Solubility Boiling point(℃) proportion Technical indicators 8～9 28.5～31.5 50～100 Completely soluble Approx. 100 Close to 1 Test results 8.4 30.3 88 Completely soluble 98 1.02

[0045] The design index of the water-based-organic polymer stabilized gravel layer 2 should be selected according to the characteristics of the flexible base layer, and the CBR value is used as the strength design index of the water-based-organic polymer stabilized gravel layer 2. The CBR test result of the water-based-organic polymer stabilized gravel layer 2 designed in Example 1 is 326.6.

[0046] The average shrinkage coefficient of water-based organic polymer stabilized gravel layer 2 is 57.51×10 -6 The test results of temperature shrinkage coefficient are shown in Table 4. It can be seen that the temperature shrinkage coefficient of the stabilized material is much lower than that of the cement stabilized material. The water-based-organic polymer stabilized crushed stone material has good resistance to low-temperature shrinkage cracking.

[0047] Table 4 Water-based-organic polymer stabilized gravel temperature shrinkage test results

[0048] Temperature range (℃) 30～20 20～10 10～0 0～-10 -10～-20 <![CDATA[Temperature strain (10 -5 )]]> 2.99 2.49 3.24 3.74 4.73 <![CDATA[Coefficient of thermal contraction (10 -6 )]]> 2.99 2.49 3.24 3.74 4.73

[0049] Example 2

[0050] Reference Figure 2 , which is different from Example 1 in that, in this embodiment, a cement stabilized gravel layer 5 is also laid between the adhesive layer oil 3 and the water-based-organic polymer stabilized gravel layer 2;

[0051] The thickness of the cement-stabilized crushed stone layer 5 is 18 cm to 25 cm;

[0052] In areas where the bearing capacity of the old road structure layer 4 is weak, adding a semi-rigid subbase layer after milling: cement-stabilized crushed stone layer 5 can effectively improve the bearing capacity of the pavement structure;

[0053] The bearing capacity of the old road structure layer 4 is relatively weak, and it needs to be milled to remove the surface wear and loose materials, clean the road surface dust, and then carry out the design of the road structure for reconstruction and expansion; the additional road structure layers are asphalt surface layer 1, water-based-organic polymer stabilized gravel layer 2, cement stabilized gravel layer 5, and tack coat 3 from top to bottom, and the tack coat 3 is laid on the old road structure layer 4;

[0054] The pavement structure materials and thickness are:

[0055] The asphalt surface layer 1 is 4cmSBS-AC13+6cmAC20+8cmAC25, the thickness of the water-based-organic polymer stabilized gravel layer 2 is 20cm, and the thickness of the cement stabilized gravel layer 5 is 22cm;

[0056] Spread tack coat 3 between the added pavement structure layer and the old road structure layer 4 to ensure the bonding performance with the old road; the tack coat 3 uses emulsified asphalt modified by SBR composite binder, and the dosage is 0.6kg / m2;

[0057] The water-based-organic polymer stabilized gravel layer 2 is composed of water-based-organic polymer, water, coarse aggregate, fine aggregate and mineral powder; the water-based-organic polymer emulsion accounts for 0.5% of the total weight of the aggregate, the optimal water content is 4.13%, the proportion of mineral powder is 5%, and the design results of different particle size gradations are shown in Table 5.

[0058] Table 5 Water-based-organic polymer stabilized gravel gradation design results

[0059] Screen size (mm) 7.5 31.5 26.5 19 16 13.2 9.5 4.75 2.36 0.6 0.3 0.075 Pass rate (%) 100.0 98.1 86 74.5 73.2 67.7 54.9 41.7 30.6 17.6 10.9 4.5 Required range (%) 100.0 90～100 79～95 60～85 53～80 48～74 40～65 25～50 18～40 9～25 6～20 0～7

[0060] The aggregate and water-based-organic polymer emulsion used in this embodiment are the same as those used in Example 1, so the test results of the aggregate and the water-based-organic polymer emulsion are the same as those in Example 1;

[0061] The design index of the water-based-organic polymer stabilized gravel layer 2 should be selected according to the characteristics of the flexible base layer, and the CBR value should be used as the strength design index of the water-based-organic polymer stabilized gravel layer 2, and its CBR design value is 195;

[0062] The average shrinkage coefficient of the water-based organic polymer stabilized gravel layer 2 is 22×10 -6 The test results of the temperature shrinkage coefficient are shown in Table 6. The temperature shrinkage coefficient of the stabilized material is much lower than that of the cement stabilized material. It can be seen that the water-based-organic polymer stabilized crushed stone material has good resistance to low-temperature shrinkage cracking.

[0063] Table 6 Water-based-organic polymer stabilized gravel temperature shrinkage test results

[0064] Temperature range (℃) 30～20 20～10 10～0 0～-10 -10～-20 <![CDATA[Temperature strain (10 -5 / ℃)]]> 2.714 2.801 3.163 3.792 4.330 <![CDATA[Coefficient of thermal contraction (10 -6 / °C)]]> 2.714 2.801 3.163 3.792 4.330

[0065] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0066] The embodiments described above are only descriptions of the preferred methods of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A cement pavement reconstruction and expansion pavement structure with anti-reflective cracking, characterized in that: include: A bottom layer, the bottom layer comprising an old road structure layer (4); A flexible base layer, the flexible base layer comprising a water-based-organic polymer stabilized gravel layer (2) laid on the old road structure layer (4), and a tack coat oil (3) laid between the water-based-organic polymer stabilized gravel layer (2) and the old road structure layer (4); The upper layer comprises an asphalt surface layer (1), and the asphalt surface layer (1) is laid on the water-based-organic polymer stabilized crushed stone layer (2).

2. The cement pavement reconstruction and expansion structure with anti-reflective cracking according to claim 1 is characterized by: A cement stabilized gravel layer (5) is also laid between the adhesive layer oil (3) and the water-based-organic polymer stabilized gravel layer (2).

3. The cement pavement reconstruction and expansion structure with anti-reflective cracking according to claim 1 is characterized by: The tack coat oil (3) is emulsified asphalt modified by SBR composite binder.

4. The cement pavement reconstruction and expansion structure with anti-reflective cracking according to claim 1 is characterized by: The asphalt surface layer (1) comprises a first asphalt layer, a second asphalt layer and a third asphalt layer which are laid in sequence from top to bottom, the first asphalt layer is a modified asphalt mixture, and the second asphalt layer and the third asphalt layer are both ordinary asphalt mixtures.

5. The cement pavement reconstruction and expansion structure with anti-reflective cracking according to claim 1 is characterized by: The total thickness of the asphalt surface layer (1) is 10 cm-18 cm.

6. The cement pavement reconstruction and expansion structure with anti-reflective cracking according to claim 1 is characterized by: The thickness of the water-based-organic polymer stabilized gravel layer (2) is 18 cm to 24 cm.

7. The cement pavement reconstruction and expansion structure with anti-reflective cracking according to claim 2 is characterized by: The thickness of the cement-stabilized crushed stone layer (5) is 18 cm to 25 cm.

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