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CN-120794554-B - High-doping phosphogypsum pavement base material and preparation method thereof

CN120794554BCN 120794554 BCN120794554 BCN 120794554BCN-120794554-B

Abstract

The invention discloses a high-doping phosphogypsum pavement base material and a preparation method thereof, belonging to the field of pavement base materials. The material comprises, by weight, 7-9 parts of binder, 30-45 parts of phosphogypsum artificial fine aggregate, 45-60 parts of phosphogypsum artificial coarse aggregate and 0.05-0.1 part of water glass, wherein the binder is formed by mixing 3.5-4.5 parts of phosphogypsum, 3-3.5 parts of slag powder, 0.3-0.7 part of cement and 0.2-0.3 part of phosphorus slag powder. The phosphogypsum artificial aggregate is prepared by mixing phosphogypsum, slag powder, cement, a performance regulator, water and a water reducing agent, and then pouring, maintaining, crushing, shaping and sieving. The preparation method of the material comprises three steps of pretreatment of aggregate, material mixing and molding maintenance. The invention realizes the high-doping utilization of phosphogypsum, solves the technical problems that the utilization rate and the road performance of the phosphogypsum in the prior phosphogypsum road surface base material can not be simultaneously considered and the construction convenience is poor, and the obtained material has good road performance.

Inventors

  • LI ZHANGJIAN
  • WANG MOBI
  • DU XIONGBIN
  • YU JINYANG
  • ZHANG LONG
  • ZENG CAICHAO
  • ZHANG JIAXIANG
  • WANG SHENGZHU
  • HAN ZHONGYUE

Assignees

  • 云南建投绿色高性能混凝土股份有限公司

Dates

Publication Date
20260508
Application Date
20250723

Claims (7)

  1. 1. The high-doping phosphogypsum pavement base material is characterized by comprising, by weight, 7-9 parts of binder, 30-45 parts of phosphogypsum artificial fine aggregate, 45-60 parts of phosphogypsum artificial coarse aggregate and 0.05-0.1 part of water glass, wherein the binder is prepared by mixing 3.5-4.5 parts of phosphogypsum, 3-3.5 parts of slag powder, 0.3-0.7 part of cement and 0.2-0.3 part of phosphorus slag powder; 45-55 parts of phosphogypsum, 25-37 parts of slag powder, 0-5 parts of cement and 5-8 parts of performance regulator are added with water with the total mass of 0.23-0.24 times and a polycarboxylate water reducer with the total mass of 0.02-0.025 times, and the mixture is mixed and stirred, and then poured, maintained, mechanically crushed, shaped and screened to form particles with the grading and particle shape meeting the requirements; the performance regulator is prepared by mixing, by weight, 2-3 parts of fly ash, 1.5-2.5 parts of metakaolin, 1-1.5 parts of silica fume and 0.5-1 part of steel slag powder through drying; The modulus of the water glass is 1.5-2.5.
  2. 2. The high-doping phosphogypsum pavement base material according to claim 1, wherein the phosphogypsum artificial coarse aggregate is a mixture with a nominal particle size of 4.75-9.5 mm and 9.5-26.5mm, the ratio of the mixture to the phosphogypsum artificial coarse aggregate is 1:6-9, and the nominal particle size of the phosphogypsum artificial fine aggregate is 0-4.75: 4.75 mm.
  3. 3. The high-doping phosphogypsum pavement base material of claim 1, wherein the solid content of the polycarboxylate water reducer is 8-12%, and the water reducing rate is more than or equal to 25%.
  4. 4. The high-doping phosphogypsum pavement base material according to claim 1, wherein the phosphogypsum is original phosphogypsum with the grain diameter of less than 2.36mm after being crushed, the cement is P-042.5 cement, and the slag powder is S95-level granulated blast furnace slag powder.
  5. 5. A method for preparing the phosphogypsum pavement base material with high doping amount according to any one of claims 1 to 4, which is characterized by comprising the following steps: (1) Pretreating aggregate, namely adding water which is 2-3% higher than the water saturation and dry water absorption rate of the fine aggregate, uniformly stirring, and stewing for 24-48 hours; (2) Mixing the binder, the pretreated phosphogypsum artificial fine aggregate and the phosphogypsum artificial coarse aggregate uniformly, dissolving water glass in water, adding the water glass into the mixture, and uniformly stirring; (3) And (3) molding and curing, namely molding and curing the mixture to obtain the base material.
  6. 6. The method according to claim 5, wherein the amounts of the artificial fine phosphogypsum aggregate and the artificial coarse phosphogypsum aggregate after the pretreatment in the step (2) are calculated from the actual water content, and the amount of the aggregate after the pretreatment=dry mass of the aggregate× (water content after saturation of 1+.
  7. 7. The method according to claim 5, wherein the amount of water in step (2) is =total water usage-dry aggregate mass× (water content after saturation-saturation dry water absorption), and the total water usage is determined by a compaction test.

Description

High-doping phosphogypsum pavement base material and preparation method thereof Technical Field The invention relates to the field of pavement base materials, in particular to a high-doping phosphogypsum pavement base material and a preparation method thereof. Background Along with the development of industrial production, phosphogypsum is taken as an industrial byproduct generated in the production process of phosphate fertilizer, phosphoric acid and derivatives thereof, the stocking quantity is increased year by year, and a large amount of land resources are occupied, and environmental pollution is possibly caused. The application of phosphogypsum to road base materials is one of the important ways to realize the resource utilization of phosphogypsum. At present, the application of phosphogypsum in road base layers at home and abroad has been studied more and developed to a certain extent. Phosphogypsum pavement base materials can be divided into powder materials, aggregate materials and flow molding materials according to the raw material composition and the material form. The powder phosphogypsum pavement base material is prepared by mixing phosphogypsum with cementing materials, curing agents, other auxiliary materials and the like and is used for pavement base. For example, patent CN114804773a proposes a composite solid waste pavement base binder, which is formed by mixing pretreated alkaline phosphogypsum powder, fly ash, slag powder and cement, and can improve the strength of pavement base, reduce shrinkage cracking of pavement base, reduce cement consumption and reduce cost. Patent CN119430836a discloses an phosphogypsum road base material, which comprises 850-900 parts of phosphogypsum, 5-15 parts of quicklime, 40-60 parts of cement, 55-85 parts of composite curing agent and 8.5-13 parts of curing activator, and the strength and stability of the base material are improved by modifying and curing soluble phosphorus and soluble fluorine in phosphogypsum. The aggregate phosphogypsum pavement base material is prepared by mixing phosphogypsum, cementing material, curing agent, auxiliary material and the like with aggregate. Wherein the aggregate is natural aggregate or phosphogypsum aggregate prepared by taking phosphogypsum as a main raw material through centrifugal rolling, extrusion and other modes. For example, CN119638356a discloses a high-doped phosphogypsum-cement stabilized macadam mixture, which comprises, by weight, 100-120 parts of graded macadam, 60-80 parts of phosphogypsum, 5-10 parts of cement, 1-3 parts of curing agent, and 5-15 parts of water. Lv Wei et al, in the study of the application of modified phosphogypsum lightweight aggregate in roadbed materials (published in concrete and cement products, 2022, 6 th edition, pages 82-86), propose granulating phosphogypsum into balls and sieving to obtain phosphogypsum lightweight aggregate, and using phosphogypsum lightweight aggregate to replace broken stone partially for the preparation of road stabilizing layers. When the mixing amount of phosphogypsum in the phosphogypsum lightweight aggregate is 88%, the unconfined compressive strength of the stabilizing layer 7d is more than or equal to 3MPa. The flow-molding phosphogypsum pavement base material is formed by mixing phosphogypsum, cementing material, aggregate and the like, adding water and an additive, and stirring to form a base mixture with certain fluidity, and pouring and molding in situ. For example, CN119191800A proposes a self-compacting phosphogypsum road base material, which comprises, by mass, 40-55% of phosphogypsum, 4-13% of a cementing material, 35-50% of aggregate and 0.2-0.7% of an additive. The slump expansion index of the base material reaches SF1 level (550-655 mm), the expansion time T 500 reaches VS1 level (more than or equal to 2 s), the cement consumption is low, the phosphogypsum utilization rate is high, and the early diseases of the road base can be effectively overcome or avoided. However, the phosphogypsum is widely used for the pavement base layer at present, but due to the limitation of the utilization method and the like, the phosphogypsum is difficult to achieve multi-party consideration on the utilization rate of the phosphogypsum, the pavement performance of the base layer material, the construction convenience, the practicability and the like, and the large-scale application of the phosphogypsum on the pavement base layer is limited. The following problems are presented in detail: Firstly, phosphogypsum in a powder phosphogypsum pavement base material is not easy to mix with binder uniformly, multiple kinds of road rollers are required to be matched for multiple times of rolling, construction is complex, compactness is difficult to reach standard requirements, pavement performance is poor, and diseases are easy to occur after the pavement is put into use. And secondly, adding common aggregate into the aggregate phosphogypsum pavement base material to r