An asphalt concrete pavement structure with an inverted phosphogypsum stabilized base

Abstract

This utility model relates to the fields of road traffic and civil engineering technology, specifically an asphalt concrete pavement structure with an inverted phosphogypsum-stabilized base course. It includes a phosphogypsum base course situated above a subgrade, a subbase course above the subbase course, a connecting layer above the subbase course, a structural layer above the connecting layer, and an anti-skid layer above the structural layer. The phosphogypsum base course is made of phosphogypsum cement-stabilized crushed stone, and also incorporates fly ash and lime additives. A waterproof geotextile is applied to the lower surface and the lower surface of the phosphogypsum base course. The lower surface of the lower waterproof geotextile is bonded to the upper surface of the subgrade, and the upper surface of the upper waterproof geotextile is bonded to the lower surface of the subbase course. The subbase course is a graded crushed stone conditioning layer, the connecting layer is penetrating asphalt crushed stone, the structural layer is asphalt concrete, and the anti-skid layer is also made of asphalt concrete. The upper surface of the anti-skid layer is treated with roughening and anti-skid performance enhancements. This utility model improves the structural strength of the phosphogypsum base course pavement.

Description

Technical Field

[0001] This utility model relates to the field of road traffic and building civil engineering technology, specifically an asphalt concrete pavement structure with an inverted phosphogypsum stabilized base. Background Technology

[0002] Phosphogypsum is an industrial solid waste. The applicant has conducted extensive research and practice on the engineering utilization of phosphogypsum-stabilized base and subbase. The applicant has also conducted engineering test sections on the conventional asphalt concrete pavement structure based on semi-rigid base: asphalt concrete surface layer + asphalt concrete middle and lower layers + phosphogypsum-stabilized base + subbase. After a period of operation, in general, compared with cement-stabilized crushed stone semi-rigid base road sections, there are still problems of insufficient durability and poor road performance. Utility Model Content

[0003] The purpose of this invention is to provide an asphalt concrete pavement structure with an inverted phosphogypsum-stabilized base course, which solves the problems of insufficient water stability and durability of the phosphogypsum base course, improves the structural strength of the phosphogypsum base course pavement, can absorb phosphogypsum on a large scale, and eliminates or reduces the leakage of harmful substances from phosphogypsum through structural combination, thus contributing to environmental protection.

[0004] The specific technical solution adopted by this utility model is as follows:

[0005] An asphalt concrete pavement structure with an inverted phosphogypsum stabilized base course is disclosed. The asphalt concrete pavement structure includes a phosphogypsum base course disposed above a subgrade, a subbase course on the phosphogypsum base course, a connecting layer on the subbase course, a structural layer on the connecting layer, and an anti-skid layer on the structural layer. Subgrade and roadbed structures are provided on both sides of the asphalt concrete pavement structure.

[0006] Preferably, the phosphogypsum base layer is made of phosphogypsum cement-stabilized crushed stone mixed with a certain proportion of fly ash and lime additives. The lower surface of the phosphogypsum base layer and the lower surface of the base layer are covered with waterproof geotextile. The lower surface of the lower waterproof geotextile is in contact with the upper surface of the subgrade, and the upper surface of the upper waterproof geotextile is in contact with the lower surface of the base layer.

[0007] Preferably, the subbase is a graded crushed stone conditioning layer, the connecting layer is a penetrating asphalt crushed stone, the structural layer and the anti-skid layer are both made of asphalt concrete, and the upper surface of the anti-skid layer is treated to improve its roughness and anti-skid performance.

[0008] Preferably, the waterproof geotextile is a two-layer geotextile with a membrane, and the weight of the geotextile per square meter is not less than 200g / m². 2 The membrane weight per square meter shall not be less than 200g / m². 2 The total weight of the two fabrics sandwiching one membrane shall not be less than 600g / m². 2The overlap of the waterproof geotextile shall not be less than 50cm, and it shall be bonded with waterproof adhesive.

[0009] The technical effects achieved by this utility model are as follows:

[0010] Compared with traditional semi-rigid asphalt pavement structures, this utility model, through optimized phosphogypsum mix design and the incorporation of a certain proportion of fly ash, lime and other additives, forms non-cement stabilized crushed stone, improving the unconfined compressive strength of the phosphogypsum stabilized crushed stone. This meets the base course specification requirement of 3-6 MPa unconfined compressive strength after 7 days, greatly improving the road performance of the phosphogypsum base course; achieving the goal of large-scale utilization of phosphogypsum, and realizing better ecological, economic and social benefits.

[0011] The phosphogypsum-stabilized crushed stone base course is inverted beneath the graded crushed stone subbase and wrapped with waterproof geotextile. This structure significantly improves the water stability and durability of the phosphogypsum-stabilized crushed stone base course. The waterproof geotextile wrapping seals the phosphogypsum-stabilized crushed stone base course, eliminating the problem of softening strength reduction caused by capillary water rising from the subgrade and seepage water from the pavement. The phosphogypsum cement-stabilized crushed stone used in the phosphogypsum base course is centrally mixed in a stabilized soil mixing plant. The asphalt concrete pavement structure is used for highways and municipal roads; it is also suitable for logistics parks and industrial park roads, and has wide applicability. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the connection between the asphalt concrete pavement structure and the roadbed and trough of this utility model;

[0013] Figure 2 This is a schematic diagram of the overall hierarchical cross-sectional structure of this utility model.

[0014] Appendix Figure 1-2 The list of components represented by each number is as follows:

[0015] 1. Anti-skid layer; 2. Structural layer; 3. Connecting layer; 4. Subbase; 5. Waterproof geotextile; 6. Phosphogypsum base layer; 7. Subgrade; 8. Roadbed and trough structure. Detailed Implementation

[0016] To make the objectives and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of this utility model and does not strictly limit the scope of protection specifically claimed by this utility model.

[0017] like Figures 1-2The embodiment shown illustrates an asphalt concrete pavement structure with an inverted phosphogypsum stabilized base course. The asphalt concrete pavement structure includes a phosphogypsum base course 6 positioned above a subgrade 7. The phosphogypsum base course 6 has a subbase course 4, a connecting layer 3, a structural layer 2, and an anti-skid layer 1. Subgrade and roadbed structures 8 are provided on both sides of the asphalt concrete pavement structure.

[0018] The phosphogypsum base course 6 is made of phosphogypsum cement-stabilized crushed stone mixed with a certain proportion of fly ash and lime additives. By adding a certain proportion of fly ash and lime additives, a new type of semi-rigid base course of non-cement stabilized crushed stone is formed. The phosphogypsum base course 6 replaces cement stabilized crushed stone and still belongs to the semi-rigid base course pavement structure. The lower and upper surfaces of the phosphogypsum base course 6 are covered with waterproof geotextile 5. The lower surface of the lower waterproof geotextile 5 is bonded to the upper surface of the subgrade 7, and the upper surface of the upper waterproof geotextile 5 is bonded to the lower surface of the subbase 4.

[0019] In this embodiment of the invention, the phosphogypsum base layer 6 is wrapped with waterproof geotextile 5 to block rising capillary water and infiltrating rainwater, effectively solving the problem of the phosphogypsum base layer 6 softening and weakening when exposed to water.

[0020] The base course 4 is a graded crushed stone conditioning layer, the connecting layer 3 is a penetrating asphalt crushed stone, the structural layer 2 is asphalt concrete, and the anti-skid layer 1 is also asphalt concrete. By setting the connecting layer 3 with a penetrating asphalt crushed stone structure, the tensile stress at the bottom of the asphalt concrete structural layer 2 can be reduced. The upper surface of the anti-skid layer 1 is treated with roughness and anti-skid performance.

[0021] By inverting the phosphogypsum base layer 6 under the graded crushed stone subbase layer 4, it is beneficial to solve the construction process control problem and improve stability.

[0022] The waterproof geotextile 5 adopts a two-layer fabric sandwiched with a membrane structure, and the weight of each fabric is not less than 200g / m². 2 The membrane weight per square meter shall not be less than 200g / m². 2 The total weight of the two fabrics sandwiching one membrane shall not be less than 600g / m². 2 The waterproof geotextile 5 overlaps by no less than 50cm and is bonded with waterproof adhesive.

[0023] The phosphogypsum base layer 6 uses phosphogypsum cement-stabilized crushed stone, which is centrally mixed in a stabilized soil mixing plant to mix the phosphogypsum stabilized crushed stone mixture.

[0024] The obtained asphalt concrete pavement structure is suitable for use on highways and municipal roads, as well as for logistics parks and industrial park roads, and has wide applicability.

[0025] Compared with traditional semi-rigid asphalt pavement structures, by optimizing the mix design of phosphogypsum and incorporating a certain proportion of fly ash and lime as additives, non-cement stabilized crushed stone is formed, which improves the unconfined compressive strength of phosphogypsum stabilized crushed stone and meets the base course specification requirement of 3 MPa to 6 MPa unconfined compressive strength after 7 days. This greatly improves the road performance of phosphogypsum base course 6, achieves the goal of large-scale disposal of phosphogypsum, and realizes ecological, economic and social benefits.

[0026] The construction steps of this utility model embodiment are as follows:

[0027] First, the subgrade and roadbed structure 8 is inspected and accepted. After the subgrade and roadbed structure 8 passes the inspection, the pavement construction will proceed.

[0028] Secondly, lay 5 rolls of waterproof geotextile. The waterproof geotextile consists of two layers of fabric sandwiched with a membrane; the total weight of the two layers of fabric and the membrane should not be less than 600g / m². 2 The overlap of the waterproof geotextile should be no less than 50cm, and it should be bonded with waterproof adhesive.

[0029] Third, a centralized mixing plant for stabilized soil is used to mix the phosphogypsum-stabilized crushed stone mixture according to the parameters and process requirements that meet the standards of the laboratory mix proportion test, so as to obtain phosphogypsum-cement-stabilized crushed stone mixture.

[0030] Fourth, a paver is used to pave the phosphogypsum cement-stabilized crushed stone mixture, and a roller with a capacity of 25 tons or more is used for compaction. The thickness of each layer should not exceed 20cm.

[0031] Fifth, after paving and curing are completed, waterproof geotextile 5 is wrapped around the phosphogypsum base layer 6 based on phosphogypsum cement stabilized crushed stone;

[0032] Sixth, lay graded crushed stone. The graded crushed stone is compacted by a high-frequency, low-amplitude roller to form the subbase layer 4.

[0033] Seventh, lay the bonding layer 3 based on injected asphalt. After the demulsified water evaporates, the asphalt structural layer 2 and the asphalt concrete anti-skid layer 1 can be laid.

[0034] Eighth, lay the bottom layer, the middle layer, and the anti-slip top layer in sequence.

[0035] The above description is merely a preferred embodiment of this utility model. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model. Structures, devices, and operating methods not specifically described or explained in this utility model, unless otherwise specified or limited, shall be implemented using conventional methods in the field.

Claims

1. An asphalt concrete pavement structure with an inverted phosphogypsum-stabilized base course, characterized in that: The asphalt concrete pavement structure includes a phosphogypsum base course (6) set above the subgrade (7), a subbase course (4) on the phosphogypsum base course (6), a connecting layer (3) on the subbase course (4), a structural layer (2) on the connecting layer (3), and an anti-skid layer (1) on the structural layer (2); and a roadbed and trough structure (8) is set on both sides of the asphalt concrete pavement structure.

2. The asphalt concrete pavement structure with an inverted phosphogypsum stabilized base course according to claim 1, characterized in that: The lower surface of the phosphogypsum base layer (6) is covered with waterproof geotextile (5). The lower surface of the lower waterproof geotextile (5) is attached to the upper surface of the soil base (7), and the upper surface of the upper waterproof geotextile (5) is attached to the lower surface of the subbase (4).

3. The asphalt concrete pavement structure with an inverted phosphogypsum stabilized base course according to claim 1, characterized in that: The base course (4) is a graded crushed stone conditioning layer, the connecting layer (3) is a penetrating asphalt crushed stone, the structural layer (2) and the anti-skid layer (1) are both made of asphalt concrete, and the surface of the anti-skid layer (1) is treated for roughness and anti-skid performance.

4. The asphalt concrete pavement structure with an inverted phosphogypsum stabilized base course according to claim 2, characterized in that: The waterproof geotextile (5) consists of two layers of geotextile sandwiched with a membrane, with each layer of geotextile weighing no less than 200g / m². 2 The membrane weight per square meter shall not be less than 200g / m². 2 The total weight of the two fabrics sandwiching one membrane shall not be less than 600g / m². 2 The waterproof geotextile (5) overlaps by no less than 50cm and is bonded with waterproof adhesive.

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