Rapid recovery material for cement stabilized macadam base

Abstract

The invention provides a rapid recovery material for a cement stabilized macadam base. The rapid recovery material is prepared from the following raw materials: cement, macadam, medium-coarse sand, zeolite powder, a naphthalene water reducer, an expanding agent and emulsified asphalt in a mass ratio of (160-385): (1030-1088): (512-687): (22-58): (1-2): (4-8): (0-28) (the water-binder ratio is 0.5-0.65). The mortar has the advantages of high fluidity, fast development of early strength, high compressive strength, high breaking strength, high freezing resistance and good adhesion performance of new and old base layer interfaces, and the construction process is simple.

Description

Technical Field

[0001] The invention belongs to the field of road construction, in particular to a quick recovery material for a cement-stabilized crushed stone base. Background Art

[0002] With the improvement of environmental awareness and the strengthening of economic strength, governments in various places have launched comprehensive urban environmental improvement and sewage pipe network quality improvement and efficiency enhancement projects. Drainage pipes are generally buried under the carriageway of municipal roads. In view of the large width of the carriageway of municipal roads, drainage pipe construction mostly adopts longitudinal grooving. After replacing the drainage pipes, the original road surface structure is restored. Cement-stabilized crushed stone base is the most widely used in the base of high-grade urban roads in my country. Cement-stabilized crushed stone base is a mixture formed by mixing cement as a binder and graded crushed stone as an aggregate. This base has high initial strength, and the strength quickly forms a plate body with increasing age. It has high strength, good impermeability and frost resistance, so it is widely used in road construction in my country. According to the "Code for Construction and Quality Acceptance of Urban Road Engineering", the cement-stabilized crushed stone base needs to be maintained at room temperature for 7 days, and the asphalt surface layer can be paved only after the compressive strength meets the requirements. Municipal roads are important passages for residents to travel. Long-term enclosure and closure construction of municipal roads bring great inconvenience to residents. How to shorten the construction time, reduce the impact on residents' travel, and quickly restore the road structure has become an urgent issue. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art and to provide a rapid recovery material for cement-stabilized gravel base, which has the advantages of high fluidity, rapid early strength development, strong compressive strength, high flexural strength, strong frost resistance, good adhesion performance at the interface between new and old bases, and simple construction process.

[0004] As conceived above, the technical solution of the present invention is: a rapid recovery material for cement-stabilized gravel base, characterized in that it is prepared from the following raw materials in the following mass proportions: cement: gravel: medium-coarse sand: zeolite powder: naphthalene-based water reducer: expansion agent: emulsified asphalt = 160-385: 1030-1088: 512-687: 22-58: 1-2: 4-8: 0-28 (water-cement ratio 0.5-0.65).

[0005] Preferably, the best mass ratio of the above raw materials is: cement: crushed stone: medium coarse sand: zeolite powder: naphthalene-based water reducer: expansion agent: emulsified asphalt = 385:1030:687:58:2:8:28 (water-cement ratio 0.5).

[0006] Preferably, the optimal mass ratio of the above-mentioned raw materials is: cement: crushed stone: medium-coarse sand: zeolite powder: naphthalene-based water reducer: expansion agent: emulsified asphalt = 160:1088:512:22:1:4:0 (water-cement ratio 0.65).

[0007] Preferably, the expansion agent is a low-alkali U-type expansion agent.

[0008] Preferably, the above-mentioned emulsified asphalt adopts slow-cracking cationic emulsified asphalt.

[0009] The present invention has the following advantages and technical effects:

[0010] 1. The naphthalene-based high-efficiency early-strength water-reducing agent in the raw materials of the present invention can achieve high fluidity and super early strength of the mixture. Adding a certain amount of zeolite powder can reduce the amount of cement, reduce the project cost, and increase the workability of the mixture and improve the later strength.

[0011] 2. The raw material of the present invention coats the surface of the coarse aggregate (crushed stone) with an appropriate amount of emulsified asphalt, which can reduce the rigidity of the mixture and achieve coordination between the mechanical properties of the mixture and the cement-stabilized graded crushed stone. Therefore, the mixture uses emulsified asphalt as the first binder and cement mortar as the second binder, meeting the requirements of the specification for the strength and rigidity of the cement-stabilized crushed stone base.

[0012] 3. The invention has high fluidity and a slump of ≥180mm. The mixture automatically fills and compacts the road surface grooves under its own gravity, and can achieve self-leveling, self-compacting, no water seepage, and no segregation. After the mixture is mixed evenly, it does not need to be spread and rolled by construction machinery, and only needs to be simply smoothed manually.

[0013] 4. The invention has super early strength. After the mixture is cured for 10 hours, the unconfined compressive strength reaches 4MPa, which meets the conditions for surface layer construction and can be implemented as soon as possible.

[0014] 5. The overall performance of the new and old bases of the present invention is good. The resilient modulus of the mixture is equivalent to that of the old cement-stabilized crushed stone base, the new and old interfaces have strong bonding force, and can form an organic whole. The new and old bases work together, and the road surface structure is stable.

[0015] 6. The present invention simplifies the construction process, effectively shortens the maintenance time of the base layer, develops traffic early, reduces the impact on the travel of surrounding residents, and has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of restoration of cement stabilized gravel base of the present invention.

[0017] In the figure: 1- surface layer; 2- base layer; 3- sub-base layer; 4- rainwater and sewage pipes. DETAILED DESCRIPTION

[0018] The invention provides a rapid recovery material for a cement-stabilized crushed stone base, which is laid between a pavement surface layer 1 and a pavement subbase layer 3.

[0019] Example 1: The specific components and mass ratios are: ordinary Portland cement: crushed stone: medium coarse sand: zeolite powder: naphthalene early strength water reducing agent: low alkali U-type expansion agent: slow cracking cationic emulsified asphalt = 385:1030:687:58:2:8:28 (water-cement ratio 0.5). The cement is Tianjin "Zhengtong" brand 425 ordinary Portland cement, and the zeolite powder is Beijing "Yuhengyuan" zeolite powder.

[0020] The specific construction method is:

[0021] 1. After the road is excavated, the rainwater and sewage pipes 4 shall be constructed in accordance with the "Construction and Acceptance Specifications for Water Supply and Drainage Pipeline Engineering" (GB50268);

[0022] 2. According to the "Criteria for Construction and Quality Acceptance of Urban Road Engineering" (CJJ1-2008), backfill in layers and compact the roadbed filler to the road surface subbase in three layers;

[0023] 3. According to the "Criteria for Construction and Quality Acceptance of Urban Road Engineering" (CJJ1-2008), the road subbase 3 is restored to its original road surface structure and compacted;

[0024] 4. Mix the mixture in the above mass ratio evenly and transport it to the road construction site;

[0025] 5. Pour the cement stabilized gravel quick recovery mixture provided by the present invention into the road trench and smooth it. The filling thickness shall be based on the original cement stabilized gravel thickness;

[0026] 6. After 10 hours of watering and curing, the compressive strength and CBR value were tested in accordance with the "Highway Geotechnical Test Code" (JTG3430-2020). The test result showed that the unconfined compressive strength was 3.8MPa, which met the requirements of the specification;

[0027] 7. Carry out road surface construction in accordance with the "Code for Construction and Quality Acceptance of Urban Road Engineering" (CJJ1-2008) and open to traffic.

[0028] Example 2: The specific components and mass ratios are: cement: crushed stone: medium coarse sand: zeolite powder: naphthalene early strength water reducing agent: low alkali U-type expansion agent: emulsified asphalt = 160: 1088: 512: 22: 1: 4: 0 (water-cement ratio 0.65). The cement is Tianjin "Zhengtong" brand 425 ordinary Portland cement, and the zeolite powder is Beijing "Yuhengyuan" zeolite powder.

[0029] The specific construction method is:

[0030] 1. After the road is excavated, the rainwater and sewage pipes 4 shall be constructed in accordance with the "Construction and Acceptance Specifications for Water Supply and Drainage Pipeline Engineering" (GB50268);

[0031] 2. According to the "Criteria for Construction and Quality Acceptance of Urban Road Engineering" (CJJ1-2008), backfill in layers and compact the roadbed filler to the road surface subbase in three layers;

[0032] 3. According to the "Criteria for Construction and Quality Acceptance of Urban Road Engineering" (CJJ1-2008), the road subbase 3 is restored to its original road surface structure and compacted;

[0033] 4. Mix the mixture in the above mass ratio evenly and transport it to the road construction site;

[0034] 5. Pour the cement-stabilized gravel rapid recovery mixture provided by the present invention into the road trench and smooth it. The filling thickness shall be based on the original cement-stabilized gravel thickness;

[0035] 6. After 10 hours of watering and curing, the compressive strength and CBR value were tested in accordance with the "Highway Geotechnical Test Code" (JTG3430-2020). The test result showed that the unconfined compressive strength was 4.1MPa, which met the requirements of the specification;

[0036] 7. Carry out road surface construction in accordance with the "Code for Construction and Quality Acceptance of Urban Road Engineering" (CJJ1-2008) and open to traffic.

[0037] The present invention has good bonding performance with the existing cement-stabilized crushed stone base, and the base can be opened to traffic 10 hours after construction. It has good durability, and the strength increases steadily in the later period. It has good coordination with the existing cement-stabilized crushed stone base in terms of mechanical properties, and can form a better base as a whole to jointly bear the load transmitted by the vehicle. The present invention provides a solution for effectively shortening the base maintenance time, solving the problem of quickly restoring the asphalt pavement, and reducing the impact on residents' travel.

[0038] Finally, all the parts not described in the present invention adopt mature products and mature technical means in the prior art.

[0039] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A rapid recovery material for cement-stabilized crushed stone base, characterized by: The following raw materials are prepared according to the following mass proportions: cement: crushed stone: medium-coarse sand: zeolite powder: naphthalene-based water reducer: expansion agent: emulsified asphalt = 160-385: 1030-1088: 512-687: 22-58: 1-2: 4-8: 0-28 (water-cement ratio 0.5-0.65).

2. The rapid recovery material for cement-stabilized crushed stone base according to claim 1, characterized in that: The best mass ratio of the above raw materials is: cement: crushed stone: medium coarse sand: zeolite powder: naphthalene water reducer: expansion agent: emulsified asphalt = 385:1030:687:58:2:8:28 (water-cement ratio 0.5).

3. The rapid recovery material for cement-stabilized crushed stone base according to claim 1, characterized in that: The best mass ratio of the above raw materials is: cement: crushed stone: medium-coarse sand: zeolite powder: naphthalene-based water reducer: expansion agent: emulsified asphalt = 160:1088:512:22:1:4:0 (water-cement ratio 0.65).

4. The rapid recovery material for cement-stabilized crushed stone base according to claim 1, characterized in that: The above-mentioned expansion agent adopts a low-alkali U-type expansion agent.

5. The rapid recovery material for cement-stabilized crushed stone base according to claim 1, characterized in that: The emulsified asphalt described above adopts slow-cracking cationic emulsified asphalt.

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