Ardealite road structure, material and construction method

Abstract

The invention discloses an ardealite road structure, a material and a construction method, an ardealite construction road is made of an ardealite cementing material and an ardealite lightweight aggregate, a base layer is stabilized by an over-sulfurized gypsum cementing material, and a surface layer is made of ardealite concrete, so that the functional requirements of a pavement structure can be met, and the construction efficiency is improved. The strength and durability meet the design requirements, the construction cost is lower than that of an original cement concrete pavement structure, a large amount of ardealite waste materials are used, the engineering cost is reduced, the purposes of less stone excavation and green low-carbon building are achieved, and remarkable social benefits are achieved.

Description

Technical Field

[0001] The invention belongs to the field of highway engineering, and in particular relates to a phosphogypsum road structure, material and construction method. Background Art

[0002] Pavement engineering is one of the common main structures in the field of highway engineering. The pavement is the surface layer that is in direct contact with vehicles and the atmosphere. It bears the vertical force, horizontal force and impact force of large vehicle loads, and is also affected by precipitation erosion and temperature changes. Therefore, compared with other layers, the pavement should have higher structural strength, deformation resistance, better water stability and high and low temperature stability, and should be wear-resistant and impermeable. Its surface layer should have good anti-skid performance and flatness.

[0003] The materials used for pavement are mainly cement concrete, asphalt concrete, asphalt crushed stone mixture, etc. The use of asphalt concrete and cement concrete surface layers is not only costly, but also has a great impact on the environment due to large-scale quarrying or use of cement.

[0004] The storage of phosphogypsum waste has always been a major problem, causing huge impacts in many aspects, such as environmental pollution, affecting people's lives, and restricting economic development. Summary of the invention

[0005] In order to solve the above problems, the present invention aims to provide a phosphogypsum road structure, material and construction method. The new phosphogypsum lightweight aggregate concrete is used as the pavement material, and the phosphogypsum waste residue is fully utilized, which conforms to the principles of energy conservation and environmental protection, green and low carbon, and appropriate structure and material. The use of industrial waste residue, combined with a small amount of cement mixing, has a low cost and obvious economic benefits; compared with the traditional cement concrete surface layer, it saves cement and aggregate mining, which has significant advantages in areas with tight resources and lack of stone.

[0006] The technical solution of the present invention is as follows: A phosphogypsum road structure, the phosphogypsum road structure comprising from top to bottom a phosphogypsum lightweight aggregate concrete surface layer, a phosphogypsum lightweight aggregate composite stabilized base layer, a phosphogypsum roadbed filler layer and a soil base layer; the phosphogypsum lightweight aggregate composite stabilized base layer comprises a pavement base layer and a pavement subbase layer, and the phosphogypsum lightweight aggregate concrete surface layer comprises an upper surface layer and a lower surface layer.

[0007] Preferably, the thickness of the lower layer of the phosphogypsum lightweight aggregate concrete surface layer is 150mm-300mm, and the thickness of the upper layer is 3-10mm; the thickness of the pavement base layer is 280-320mm, the thickness of the pavement subbase layer is 120-200mm, and the thickness of the phosphogypsum roadbed filler layer is 550~650mm.

[0008] Preferably, the thickness of the lower layer is 180 mm, the thickness of the upper layer is 5 mm; the thickness of the road base is 300 mm, the thickness of the road subbase is 150 mm, and the thickness of the phosphogypsum roadbed filler layer is 600 mm.

[0009] The phosphogypsum road material used in the phosphogypsum construction road structure, the amount of phosphogypsum lightweight aggregate concrete surface layer per cubic meter (kg / m 3 ) includes: first phosphogypsum light aggregate 200-220 (kg / m 3 ), crushed stone 865-880 (kg / m 3 ), first phosphogypsum slag cement 405-420 (kg / m 3 ), sand 650-675 (kg / m 3 ), first phosphogypsum light aggregate 218 (kg / m 3 ), crushed stone 872 (kg / m 3 ), first phosphogypsum slag cement 414 (kg / m 3 ), sand 668 (kg / m 3 ); The first phosphogypsum slag cement 414 (kg / m 3 ) includes: the first phosphogypsum slag cement includes: cement 15-28 (kg / m 3 ), slag powder 310-335 (kg / m 3 ), modified phosphogypsum 55-70 (kg / m 3 ), preferably, cement 23 (kg / m 3 ), slag powder 328 (kg / m 3 ), modified phosphogypsum 63 (kg / m 3 ) .

[0010] Preferably, the first phosphogypsum lightweight aggregate comprises the following components by mass fraction: 80-85% of modified phosphogypsum powder, 10-15% of slag powder, 6-8% of cement, and a pH value of 10.5-12.5.

[0011] Preferably, the upper layer includes the following components in mass fraction: fiber, high-strength silica sand, polymer rubber powder, with a mass ratio of 0.05:3:1. The concrete protective layer is used to make the surface more compact and wear-resistant, and prevent the lower layer of concrete from contacting the air to produce carbonization. The manufacturer is: Wuhan Xingdeyu Building Materials Co., Ltd., China, cement-based wear-resistant material type I. It is composed of mineral alloy aggregates with a certain particle grading (copper ore sand, tin-titanium alloy sand), special cement (Far East House 52.5 cement from Taiwan, China), other admixtures and additives (German Wacker rubber powder, German Bayer calcium formate, Japanese Kao water reducer, high-content silica powder), and can be used after opening the bag. The construction process of the upper layer is: 1) The first material spreading: after the construction of the phosphogypsum lightweight aggregate composite stabilized base, two-thirds of the wear-resistant floor material will be evenly spread on the concrete surface to complete the first spreading operation. After the wear-resistant floor material absorbs a certain amount of moisture, mechanical finishing is carried out; 2) The second material spreading: before the initial setting of the concrete, the second material spreading operation is carried out, one-third of the material is spread, and the second finishing is carried out together with the concrete.

[0012] Preferably, the pavement base in the phosphogypsum lightweight aggregate stabilized base comprises the following components by mass fraction: The second phosphogypsum slag cement is 12-15%, the second phosphogypsum light aggregate is 48-55%, and the machine-made sand is 28-38%; preferably, the second phosphogypsum slag cement is 13.6%, the second phosphogypsum light aggregate is 52.6%, and the machine-made sand is 33.8%; wherein the second phosphogypsum light aggregate comprises the following components by mass fraction: 85-90% of modified phosphogypsum powder, 5-15% of slag powder, 5-10% of cement, and the pH value is 10.5-12.5; the second phosphogypsum slag cement comprises the following components by mass fraction: 4-8% of cement, 45-55% of slag powder, and 40-50% of phosphogypsum powder, preferably, 6% of cement, 50% of slag powder, and 44% of phosphogypsum powder; Preferably, the pavement subbase in the phosphogypsum lightweight aggregate stabilized base comprises the following components by mass fraction: The second phosphogypsum slag cement is 10-12%, the second phosphogypsum light aggregate is 50-60%, and the machine-made sand is 32-36%. Preferably, the second phosphogypsum slag cement is 11.2%, the second phosphogypsum light aggregate is 54%, and the machine-made sand is 34.8%; Preferably, the second phosphogypsum lightweight aggregate comprises the following components by mass fraction: 85-90% modified phosphogypsum powder, 5-15% slag powder, 5-10% cement, and a pH value of 10.5-12.5.

[0013] The second phosphogypsum lightweight aggregate: particle size coefficient 1.35, bulk density 1.156 (kg / m 3 ), apparent density (kg / m 3 ) 1.800, water absorption (%) 13.76, cylinder pressure strength (MPa) 6.0. The preparation method of the first phosphogypsum light aggregate and the second phosphogypsum light aggregate is as follows: modified phosphogypsum powder, slag powder and cement are granulated into balls through a granulation process, and then naturally cured and screened. Preferably, the phosphogypsum roadbed filler layer comprises the following components by mass fraction: 90-95% of modified phosphogypsum powder and 5-10% of a curing agent, wherein the curing agent is cement or mineral powder.

[0014] Preferably, the preparation method of the modified phosphogypsum powder is as follows: after the phosphogypsum is pretreated (harmful substances are modified and alkali is neutralized), carbide slag and quicklime are added, harmful substances such as phosphorus and fluorine are converted into precipitated salt crystals by dissolution, and then sorting treatment is performed.

[0015] The construction method of the phosphogypsum road material is characterized by: using phosphogypsum light aggregate to replace part of the crushed stone aggregate, and using ordinary silicate cement, modified phosphogypsum, slag, cement mixture, that is, phosphogypsum slag-based cementitious material to replace the cementitious material to prepare phosphogypsum light aggregate concrete.

[0016] The advantages of the present invention are: The new phosphogypsum road construction structure of the present invention not only meets the structural strength and durability requirements of the road surface layer, but also can make full use of local materials to achieve the goal of low-carbon, environmentally friendly and low-cost green construction. The strength and other properties of phosphogypsum lightweight aggregate concrete meet the surface requirements of cement concrete, and can be made into a phosphogypsum lightweight aggregate cement concrete surface layer structure, achieving the effect of being both stable and durable, and convenient to construct and economical. The strength grade of its concrete is C30, and the road surface structure is designed with corresponding curbstones, drainage facilities, etc.

[0017] The present invention adopts gypsum light aggregate water-stabilizing layer technology, and prepares an artificial aggregate by compounding other materials with 80% to 90% phosphogypsum to replace ordinary natural sand and gravel. The cementitious material is compounded with ground phosphogypsum powder, slag powder, cement and other materials to obtain a road persulfate phosphogypsum cementitious material stabilized base. According to the actual consumption of the project, the phosphogypsum light aggregate water-stabilizing layer can consume more than 20,000 tons of phosphogypsum per kilometer in a standard first-class highway. After pretreatment (modification and alkali neutralization of harmful substances), phosphogypsum is made into phosphogypsum slag-based cementitious materials and phosphogypsum lightweight aggregates, which partially replace cement and coarse and fine aggregates in traditional cement concrete products. The traditional construction process is used on site to achieve the application in cement concrete pavement projects. The proportion of phosphogypsum in phosphogypsum slag-based cementitious materials and phosphogypsum lightweight aggregates is adjusted according to the different strength requirements of the base layer and the surface layer. The amount of phosphogypsum in phosphogypsum slag-based cementitious materials is not less than 15% (of which the amount used in the base layer is about 50%, and the amount used in the surface layer is about 15%), and the amount of phosphogypsum in phosphogypsum lightweight aggregate is not less than 80% (of which the amount used in the base layer is about 90%, and the amount used in the surface layer is about 80%).

[0018] Phosphogypsum composite cementitious material (phosphogypsum slag cement) is made of ground phosphogypsum powder, slag and activator. Phosphogypsum light aggregate is granulated after cementation and curing by modified aged phosphogypsum, slag powder and cement. The purpose of high-doped phosphogypsum application is achieved by replacing part of the cementitious materials and aggregates in traditional materials in a double superposition method. Since phosphogypsum cementitious materials have the characteristics of micro-expansion and slow setting, and the stiffness of phosphogypsum artificial aggregate is different from that of crushed stone, the strength development law of phosphogypsum concrete is different from that of cement concrete. The 7d strength development reaches 45-65% of that at 28d age (80-90% for cement concrete), and there is still a certain degree of continuous growth in the later period, so the later strength is higher than that of cement concrete. If both the base and surface layers of the pavement structure use phosphogypsum concrete, the deformation of the materials of the two are coordinated and the stiffness is improved, so the thickness of the cement stabilization layer and the thickness of the concrete surface layer can be appropriately reduced, saving materials and construction workload compared with traditional cement concrete pavement structures. Traditional road structures are prone to diseases. First, the cement-stabilized base layer has low bearing capacity and is easily damaged, affecting the integrity of the pavement structure. Second, the cement concrete surface layer has a high hydration temperature and large early shrinkage, which makes the pavement prone to cracking.

[0019] In response to the above problems, this phosphogypsum road structure has the following characteristics: 1. Compared with cement, the phosphogypsum composite cementitious material has a lower early hydration temperature rise and higher strength in the later stage, so it is not easy to cause temperature cracks when used on concrete pavement; 2. Compared with ordinary crushed stone, the porous structure of phosphogypsum lightweight aggregate has a lower elastic modulus, better deformation resistance, and greater strength development in the later stage. It can resist uneven settlement of the roadbed when used in the road base. 3. Both the phosphogypsum composite cementitious material and the phosphogypsum lightweight aggregate have micro-expansion properties. The prepared phosphogypsum road concrete can compensate for the early shrinkage of concrete and avoid shrinkage cracks.

[0020] 4. Phosphogypsum lightweight aggregate has strong water storage capacity and can act as a curing agent in concrete. As cement hydrates and capillary negative pressure and humidity gradient appear inside the concrete, it releases water to inhibit the development of its autogenous shrinkage. 5. The thermal conductivity of phosphogypsum coarse aggregate is low and the thermal insulation effect is good. It is not easy to freeze in winter when used in pavement concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The phosphogypsum pavement structure of the present invention; Figure 2 Traditional cement concrete pavement structure.

[0022] Among them: upper layer 1-1, lower surface layer 1-2, pavement base layer 1-3, pavement subbase layer 1-4, phosphogypsum roadbed filling layer 1-5, cement pavement surface layer 2-1, cement pavement base layer 2-2, cement pavement subbase layer 2-3, cement pavement roadbase layer 2-4.

[0023] Figure 3 Production process flow chart of phosphogypsum lightweight aggregate cement concrete; Figure 4 Production flow chart of phosphogypsum lightweight aggregate; Figure 5 Production flow chart of phosphogypsum slag cementitious material. DETAILED DESCRIPTION

[0024] The following will be combined with the specific embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0025] A phosphogypsum road structure, the phosphogypsum road structure comprising from top to bottom a phosphogypsum lightweight aggregate concrete surface layer, a phosphogypsum lightweight aggregate composite stabilized base layer, a phosphogypsum roadbed filler layer 1-5 and a soil base layer; the phosphogypsum lightweight aggregate composite stabilized base layer comprises a pavement base layer 1-3 and a pavement subbase layer 1-4, and the phosphogypsum lightweight aggregate concrete surface layer comprises an upper surface layer 1-1 and a lower surface layer 1-2.

[0026] Preferably, the thickness of the lower layer 1-2 of the phosphogypsum lightweight aggregate concrete surface layer is 150mm-300mm, and the thickness of the upper layer 1-1 is 3-10mm; the thickness of the pavement base layer 1-3 is 280-320mm, the thickness of the pavement subbase layer 1-4 is 120-200mm, and the thickness of the phosphogypsum roadbed filler layer 1-5 is 550~650mm.

[0027] Preferably, the thickness of the lower layer 1-2 is 180 mm, the thickness of the upper layer 1-1 is 5 mm; the thickness of the road base layer 1-3 is 300 mm, the thickness of the road subbase layer 1-4 is 150 mm, and the thickness of the phosphogypsum roadbed filler layer 1-5 is 600 mm.

[0028] Phosphogypsum lightweight aggregate is a kind of artificial aggregate made of phosphogypsum as the main raw material, adding a small amount of auxiliary cementitious materials, through granulation and balling process, natural curing and screening. It has a closed microporous structure, low density, high cylinder pressure strength, high porosity, good antifreeze performance and other characteristics. It can be widely used in hydraulic engineering, highway, municipal engineering and other fields to replace the crushed stone in concrete and roadbed materials, and has high economic efficiency. See the specific production process flow chart Figure 3 , see the specific production process flow chart Figure 3The traditional cement concrete pavement materials (pavement base and pavement surface) are prepared by using phosphogypsum slag-based cementitious materials + phosphogypsum lightweight aggregate. After pretreatment (modification and alkali neutralization of harmful substances), phosphogypsum is made into phosphogypsum slag-based cementitious materials and phosphogypsum lightweight aggregate, which partially replace the cementitious materials and aggregates in traditional cement concrete products. The traditional construction process is used on site to realize the application in cement concrete pavement engineering.

[0029] The phosphogypsum slag-based cementitious material is made of ground phosphogypsum powder, slag, and activator to form a phosphogypsum composite cementitious material, and the phosphogypsum light aggregate is granulated after being cemented and solidified with modified aged phosphogypsum, slag powder, cement, etc. In the phosphogypsum slag-based cementitious material system, phosphogypsum accounts for 10% to 50% of the cementitious material, and phosphogypsum accounts for 75% to 90% of the phosphogypsum light aggregate.

[0030] Production process of phosphogypsum cement concrete: The application of phosphogypsum in cement concrete surface layer mainly adopts phosphogypsum light aggregate to replace part of crushed stone aggregate, adopts ordinary silicate cement, modified phosphogypsum, slag, cement mixture, i.e. phosphogypsum slag-based cementitious material to replace cementitious material, and prepares phosphogypsum light aggregate concrete, which is applied to road cement concrete surface layer according to traditional construction process. The specific production process flow chart is shown in Figure 3 .

[0031] Example 1 Phosphogypsum lightweight aggregate Phosphogypsum lightweight aggregate is a kind of artificial aggregate made of phosphogypsum as the main raw material, with a small amount of auxiliary cementitious materials added, through granulation and balling process, natural curing and screening. It has a closed microporous structure, low density, high cylinder pressure strength, high porosity, good antifreeze performance and other characteristics. It can be widely used in hydraulic engineering, highway, municipal engineering and other fields to replace the crushed stone in concrete and roadbed materials, and has high economic efficiency. For the specific process flow, see Figure 4 .

[0032] Due to the high strength requirement of this phosphogypsum lightweight aggregate, the recommended proportion is 75% to 90% phosphogypsum, 5% to 15% active admixture, and 5% to 10% alkaline activator. The mix design of phosphogypsum lightweight aggregate preparation is shown in Table 1-4.

[0033] Table 1 Design parameters of phosphogypsum lightweight aggregate mix ratio for base

[0034] Table 2 Performance test results of phosphogypsum lightweight aggregate for base

[0035] Table 3 Design parameters of phosphogypsum lightweight aggregate mix ratio for lower surface layer

[0036] Table 4 Technical requirements for phosphogypsum lightweight aggregate for lower surface layer

[0037] Phosphogypsum slag-based cementitious materials The phosphogypsum slag-based cementitious materials are mainly made of cement, phosphate slag and phosphogypsum. The dosage of phosphogypsum is not less than 20% (about 50% in the base water-stabilizing layer and about 20% in cement concrete). The cementitious materials are prepared by compounding slag powder and cement and other raw materials. The strength can reach more than 30MPa. For the specific process flow, see Figure 5 , the alkali activator in the figure is cement.

[0038] Alkali activator It is advisable to use 42.5 grade ordinary Portland cement or Portland cement, the performance of which meets the technical requirements of standard GB / T 175.

[0039] Slag powder It is advisable to use slag powder of grade S95 or above, which complies with the requirements of GB / T 18046.

[0040] Mix design index The cementitious material in the cement concrete surface layer is phosphogypsum slag-based cementitious material, and the concrete strength grade is not less than C30. The production process and construction process are basically the same as those of cement concrete pavement prepared with traditional crushed stone aggregates. Because the water absorption rate of phosphogypsum lightweight aggregate is relatively large, it needs to be soaked in water before use. The phosphogypsum concrete surface layer and base layer should meet the requirements of the corresponding specifications and design documents. See Table 5-6 for specific indicators.

[0041] Table 5 Technical requirements for cement concrete pavement

[0042] Table 6 Technical requirements for strength of phosphogypsum lightweight aggregate composite stabilized base and subbase

[0043] Phosphogypsum concrete material formula The road base adopts the existing technology of phosphogypsum composite stabilized base, and the road surface layer adopts phosphogypsum lightweight aggregate concrete. Its slag powder and phosphogypsum powder replace more than 90% of the cementitious materials, of which modified phosphogypsum powder accounts for 10-15%, and phosphogypsum lightweight aggregate replaces more than 20%. The water-cement ratio is 0.35-0.45, and the total amount of cementitious materials is 380-450kg per cubic meter.

[0044] The above design requirements are used to design each layer: the traditional water-stable base structure diagram in the table is Figure 2 .

[0045] 1. Base material Table 7 Ratio of phosphogypsum in pavement base (1-3) and analysis of economic benefits

[0046] Table 8 Ratio of phosphogypsum in road subbase (1-4) and economic benefit analysis

[0047] 2. Surface material Table 9 Phosphogypsum lightweight aggregate pavement layer C30 concrete mix ratio and economic benefit analysis

[0048] Economic cost savings per kilometer: base layer + sub-base layer + surface layer = 428,000 yuan + 264,000 yuan + 170,000 yuan = 862,000 yuan.

[0049] 3. Filling materials for phosphogypsum roadbed filling layer (1-5) Table 10 Design parameters of phosphogypsum roadbed filling layer (1-5) filling material mix ratio

[0050] The unconfined compressive strength of the base layer is ≥3.5MPa after 7 days, and the flexural strength of the cement concrete surface layer C30 concrete strength index is ≥5.0MPa after 28 days. The technical solution of the present invention can be used to prepare phosphogypsum for road construction.

[0051] The technical solution of the present invention is explained through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above specific embodiments to be implemented. Any improvements made by technicians in the relevant field based on the present invention, or equivalent replacement of the materials selected by the present invention, etc., fall within the scope of protection of the patent.

Claims

1. A phosphogypsum road structure, characterized in that: The phosphogypsum road construction structure comprises, from top to bottom, a phosphogypsum lightweight aggregate concrete surface layer, a phosphogypsum lightweight aggregate composite stabilized base layer, a phosphogypsum roadbed filler layer (1-5) and a soil base layer; the phosphogypsum lightweight aggregate composite stabilized base layer comprises a pavement base layer (1-3) and a pavement subbase layer (1-4), and the phosphogypsum lightweight aggregate concrete surface layer comprises an upper surface layer (1-1) and a lower surface layer (1-2).

2. The phosphogypsum road structure according to claim 1, characterized in that: The thickness of the lower layer (1-2) of the phosphogypsum lightweight aggregate concrete surface layer is 150mm-300mm, and the thickness of the upper layer (1-1) is 3-10mm; the thickness of the road base (1-3) is 280-320mm, and the thickness of the road subbase (1-4) is 120-200mm; the thickness of the phosphogypsum roadbed filler layer (1-5) is 550-650mm.

3. The phosphogypsum road structure according to claim 2, characterized in that: The thickness of the lower layer (1-2) is 180 mm, the thickness of the upper layer (1-1) is 5 mm; the thickness of the road base (1-3) is 300 mm, the thickness of the road subbase (1-4) is 150 mm, and the thickness of the phosphogypsum roadbed filler layer (1-5) is 600 mm.

4. The phosphogypsum road material used in the phosphogypsum road construction structure according to any one of claims 1 to 3, characterized in that: The amount of phosphogypsum lightweight aggregate concrete surface layer (1-2) per cubic meter (kg / m 3 )include: First phosphogypsum light aggregate 200-220 (kg / m 3 ), crushed stone 865-880 (kg / m 3 ), first phosphogypsum slag cement 405-420 (kg / m 3 ), sand 650-675 (kg / m 3 ), preferably, the first phosphogypsum light aggregate 218 (kg / m 3 ), crushed stone 872 (kg / m 3 ), first phosphogypsum slag cement 414 (kg / m 3 ), sand 668 (kg / m 3 ); The first phosphogypsum slag cement includes: cement 15-28 (kg / m 3 ), slag powder 310-335 (kg / m 3 ), modified phosphogypsum 55-70 (kg / m 3 ), preferably, cement 23 (kg / m 3 ), slag powder 328 (kg / m 3 ), modified phosphogypsum 63 (kg / m 3 ) .

5. The phosphogypsum road material according to claim 4, characterized in that: The first phosphogypsum lightweight aggregate includes the following components by mass fraction: 80-85% of modified phosphogypsum powder, 10-15% of slag powder, 5-8% of cement, and a pH value of 10.5-12.

5.

6. The phosphogypsum road material used in the phosphogypsum road construction structure according to any one of claims 1 to 3, characterized in that: The upper layer (1-1) comprises the following components in terms of mass fraction: fiber, high-strength silica sand, and polymer rubber powder.

7. The phosphogypsum road material used in the phosphogypsum road construction structure according to any one of claims 1 to 3, characterized in that: The pavement base (1-3) in the phosphogypsum lightweight aggregate stabilized base comprises the following components by mass fraction: Second phosphogypsum slag cement 12-15%, second phosphogypsum light aggregate 48-55%, machine-made sand 28-38%; preferably, second phosphogypsum slag cement 13.6%, second phosphogypsum light aggregate 52.6%, machine-made sand 33.8%; The second phosphogypsum lightweight aggregate includes the following components by mass fraction: 85-90% of modified phosphogypsum powder, 5-15% of slag powder, 5-10% of cement, and a pH value of 10.5-12.5; The second phosphogypsum slag cement comprises the following components by mass fraction: 4-8% cement, 45-55% slag powder, 40-50% phosphogypsum powder, preferably, 6% cement, 50% slag powder, and 44% phosphogypsum powder; The pavement subbase (1-4) in the phosphogypsum lightweight aggregate stabilized base comprises the following components by mass fraction: The second phosphogypsum slag cement is 10-12%, the second phosphogypsum light aggregate is 50-60%, and the machine-made sand is 32-36%. Preferably, the second phosphogypsum slag cement is 11.2%, the second phosphogypsum light aggregate is 54%, and the machine-made sand is 34.8%; The second phosphogypsum lightweight aggregate includes the following components by mass fraction: 85-90% of modified phosphogypsum powder, 5-15% of slag powder, 5-10% of cement, and a pH value of 10.5-12.

5.

8. The second phosphogypsum lightweight aggregate: particle size coefficient 1.35, bulk density 1.156kg / m 3 , apparent density 1.800 kg / m 3 , water absorption rate 13.76%, cylinder pressure strength 6.0MPa; The preparation method of the first phosphogypsum light aggregate and the second phosphogypsum light aggregate is as follows: modified phosphogypsum powder, slag powder and cement are granulated into balls through a granulation process, and then naturally cured and screened.

9. The phosphogypsum road material used in the phosphogypsum road construction structure according to any one of claims 1 to 3, characterized in that: The phosphogypsum roadbed filler layer comprises the following components by mass fraction: 90-95% of modified phosphogypsum powder and 5-10% of a curing agent, wherein the curing agent is cement or mineral powder.

10. The phosphogypsum road material used in the phosphogypsum road construction structure according to any one of claims 1 to 3, characterized in that: The preparation method of the modified phosphogypsum powder is as follows: after the phosphogypsum is pretreated, carbide slag and quicklime are added, harmful substances such as phosphorus and fluorine are converted into salt crystals by dissolution, and then sorting treatment is performed.

11. The construction method of the phosphogypsum road material according to any one of claims 4 to 9, characterized in that: The method comprises the following steps: using phosphogypsum light aggregate to replace part of the crushed stone aggregate, using silicate cement, modified phosphogypsum, slag, cement mixture, i.e. phosphogypsum slag-based cementitious material to replace the cementitious material, and preparing phosphogypsum light aggregate concrete; specifically, the method comprises the following steps: S1: the original phosphogypsum is crushed, and then the modified material is added, mixed, and aged to obtain the modified phosphogypsum; S2: Phosphogypsum slag-based cementitious material is made of ground modified phosphogypsum, slag and activator to form phosphogypsum composite cementitious material; S3: phosphogypsum light aggregate is obtained by granulating modified aged phosphogypsum, slag powder and cement after solidification; Complete the preparation of phosphogypsum lightweight aggregate concrete.

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