High-strength self-waterproof phosphogypsum roadbed material and preparation method thereof

A roadbed material and phosphogypsum technology, which is applied in the field of building materials, can solve the problems of further improvement of cost and construction process control, insufficient compressive strength of phosphogypsum roadbed filler, and inability to meet the strength requirements of high-grade pavement, so as to meet the requirements of on-site construction Requirements, excellent mechanical properties and waterproof performance, the effect of high crystallization strength

Active Publication Date: 2020-06-23
HUBEI PROVINCIAL CENT FOR QUALITY SUPERVISION AD TEST OF CONSTR ENG
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Problems solved by technology

According to the statistics of the National Development and Reform Commission, the national output of phosphogypsum has reached 60 million tons, but the comprehensive utilization rate is less than 20%.
[0003] Chinese patent CN 104909698A "A Modified Phosphogypsum Highway Subgrade Filler and Its Preparation Method" improves its gelling property by calcining phosphogypsum and mixing it with raw material phosphogypsum in a certain proportion to obtain a road base filler with a certain strength, but The compressive strength of the phosphogypsum roadbed filler obtained by this method is less than 1.5 MPa, which cannot meet the strength requirements of high-grade pavements for base materials
Chinese patent CN 108275931A "a phosphogypsum modified material and its application in road base" discloses a road base composed of modified phosphogypsum mixed with 10 kinds of raw materials such as fly ash, cement, surfactant and so on. Water-stabilized layer material, the material has a compressive strength of 5-6MPa, but its composition is extremely complex, and its cost and construction process control still need to be further improved
Chinese patent CN 108409276A "a modified phosphogypsum roadbed material" mixes phosphogypsum with sand, carbide slag and other raw materials in a certain proportion, and then adds a curing agent to make the roadbed material. The CBR value of this material meets the specification requirements after testing, but the The method involves a wide variety of raw materials, which not only leads to a utilization rate of only 40% of phosphogypsum, but also greatly increases the difficulty of production
Chinese patent CN 109626925A "Preparation method of phosphogypsum roadbed material based on high-temperature activation and hydraulicity improvement" proposes a method of preparing roadbed materials by mixing phosphogypsum with waterproofing agent and Portland cement after high-temperature activating and hydraulicity improvement. The roadbed prepared by this method The material has high strength and good volume stability, but the water repellent, cement and other additives used in this method greatly increase the production cost, and the utilization rate of phosphogypsum is still limited

Method used

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  • High-strength self-waterproof phosphogypsum roadbed material and preparation method thereof
  • High-strength self-waterproof phosphogypsum roadbed material and preparation method thereof
  • High-strength self-waterproof phosphogypsum roadbed material and preparation method thereof

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Embodiment 1～2

[0034] A high-strength self-waterproof phosphogypsum roadbed material and its preparation method, exploring the influence of different contents of crystal water modified phosphogypsum powder on the performance of roadbed materials, specifically including the following steps:

[0035] 1) The natural moisture content of phosphogypsum raw materials is determined to be 25.8% according to JTG E40-2007 of "Highway Geotechnical Test Regulations";

[0036] 2) Add the phosphogypsum raw material into the closed sintering equipment, and control the ratio of the mass (g) of phosphogypsum in the closed sintering equipment to the volume (L) of the equipment to be 240:1; and the phosphogypsum in the closed sintering equipment needs to be layered and placed in separate plates , not concentratedly stacked; then under the temperature condition of 160°C, calcined for 6, 7, 8, 9, 10h respectively (when the calcining time is 7h, 8h, corresponding to Examples 1 and 2, when the calcining time is 6, 9...

Embodiment 3～4

[0042] A high-strength self-waterproof phosphogypsum roadbed material and its preparation method, exploring the influence of different retarder content on the performance of roadbed materials, specifically including the following steps:

[0043] 1) The natural moisture content of phosphogypsum raw materials is determined to be 26.5% according to JTG E40-2007 of "Highway Geotechnical Test Regulations";

[0044] 2) Add the phosphogypsum raw material into the airtight sintering equipment, and control the ratio of the mass (g) of phosphogypsum in the airtight sintering equipment to the volume (L) of the equipment to be 260:1; and the phosphogypsum in the airtight sintering equipment needs to be layered and placed in separate trays , not stacked together; then calcined at 160°C for 8 hours, cooled, and crushed with a high-speed rotary pulverizer (rotating speed 20000-25000r / min, crushing time 5-8s), to obtain an improved crystal water content of 2.8%. Non-toxic phosphogypsum powder...

Embodiment 5～6

[0050] A high-strength self-waterproof phosphogypsum roadbed material and its preparation method, exploring the influence of different stewing materials and different time lengths on the performance of roadbed materials, specifically including the following steps:

[0051] 1) The natural moisture content of the phosphogypsum raw material is determined to be 24.6% according to JTG E40-2007 of "Highway Geotechnical Test Regulations";

[0052] 2) Add the phosphogypsum raw material into the closed sintering equipment, and control the ratio of the mass (g) of phosphogypsum in the closed sintering equipment to the volume (L) of the equipment to 200:1; and the phosphogypsum in the closed sintering equipment needs to be layered and placed in separate plates , not stacked together; then calcined at 160°C for 8 hours, cooled, and crushed with a high-speed rotary pulverizer (rotating speed 20000-25000r / min, crushing time 5-8s), to obtain an improved crystal water content of 2.8%. Non-tox...

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Abstract

The invention discloses a high-strength self-waterproof phosphogypsum roadbed material. The ardealite raw material is calcined to obtain modified ardealite powder for preparing an ardealite roadbed material. In the process of converting calcium sulfate dihydrate into hemihydrate gypsum through dehydration, generation of alpha-hemihydrate gypsum is effectively promoted by further regulating and controlling the water content and the input amount of the ardealite raw material in a closed calcining environment, so that the mechanical property and the waterproof property of the obtained ardealite roadbed material are remarkably improved. The modification method provided by the invention is extremely simple and convenient to operate, can realize 100% recycling of phosphogypsum waste, has important economic and environmental benefits, and is suitable for popularization and application.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to a high-strength self-waterproof phosphogypsum roadbed material and a preparation method thereof. Background technique [0002] Phosphogypsum is a phosphorus-containing calcium sulfate dihydrate (CaSO 4 2H 2 O) mainly Class II industrial solid waste. According to the statistics of the National Development and Reform Commission, the national output of phosphogypsum has reached 60 million tons, but the comprehensive utilization rate is less than 20%. On the other hand, the total mileage of my country's highways has exceeded 4.5 million kilometers. The development of the transportation industry is not only dedicated to the improvement of road surface performance, but also faces multiple pressures such as the lack of high-quality aggregates and the development of a green economy. Phosphogypsum has a certain hydration hardening strength. If it is used in road ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B28/14C04B11/036C04B111/27
CPCC04B28/147C04B11/036C04B2111/27C04B2111/0075C04B2201/50C04B2201/20C04B24/14Y02W30/91
Inventor 龙永双曹庭维王康周磊陈庆敏刘琦黎进
Owner HUBEI PROVINCIAL CENT FOR QUALITY SUPERVISION AD TEST OF CONSTR ENG
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