A method for treating localized subsidence of asphalt pavement using multi-modified polymer crushed stone piles

Abstract

This invention discloses a multi-modified polymer-modified crushed stone pile treatment technology for localized asphalt pavement subsidence. Utilizing the expansibility of the multi-modified polymer-modified crushed stone pile and its concentric ring graded crushed stone performance, it compacts the soil, reinforces the roadbed, and repairs subsidence problems caused by localized inadequate compaction of the roadbed in in-service asphalt pavements. The multi-modified polymer-modified crushed stone pile comprises component A, component B, and graded crushed stone. This invention employs the aforementioned multi-modified polymer-modified crushed stone pile treatment technology for localized asphalt pavement subsidence, utilizing the adhesive properties of polymers to bind the crushed stone together, forming a complete whole, thus creating a novel pile body that overcomes the shortcomings of loose piles and facilitates construction.

Description

Technical Field

[0001] This invention relates to the field of highway maintenance technology, and in particular to a method for treating localized subsidence of asphalt pavement using multi-modified polymer crushed stone piles. Background Art

[0002] my country has achieved remarkable success in highway construction, with its expressway mileage now ranking first in the world, playing a vital role in national and regional development. Furthermore, with the initial completion of the national expressway network and the increase in total expressway mileage, the demand for highway maintenance is growing daily, leading to a significant shift in highway maintenance concepts and the emergence of various new maintenance materials, technologies, processes, and equipment.

[0003] During the service life of asphalt pavements, localized settlement often occurs due to insufficient compaction of the subgrade. Crushed stone pile technology, as a commonly used method for addressing localized pavement settlement, has been widely applied in highway maintenance engineering. Crushed stone piles are composed of graded crushed stone and lack binder for confinement; they rely solely on the subgrade soil to provide lateral restraint, transferring the load at the pile top downwards. When the crushed stone piles bear large vertical loads, the relatively low strength of the subgrade soil cannot provide sufficient lateral restraint, making the crushed stone piles highly susceptible to lateral bulging failure and leading to subgrade instability.

[0004] In recent years, to overcome the drawback of crushed stone piles being prone to lateral expansion failure, scholars both domestically and internationally have conducted in-depth research on their performance. Methods such as adding vertical geotextile reinforcement and cement grouting around the crushed stone piles have been used to improve their bearing capacity. However, these methods involve complex construction procedures and long curing periods. Therefore, in the face of the problem of localized subsidence in in-service asphalt pavements, there is an urgent need to develop a new type of crushed stone pile that overcomes the shortcomings of loose-grain piles while also facilitating construction. Summary of the Invention

[0005] The purpose of this invention is to provide a method for treating localized subsidence of asphalt pavement using multi-modified polymer crushed stone piles. This method utilizes the adhesive properties of polymers to bind crushed stone together, forming a complete whole and creating a new type of pile that overcomes the shortcomings of loose piles and is convenient for construction.

[0006] To achieve the above objectives, this invention provides a method for treating localized subsidence of asphalt pavement using multi-modified polymer crushed stone piles. Utilizing the expansibility of the multi-modified polymer crushed stone piles and the performance of the graded crushed stone used to reinforce the soil and strengthen the roadbed, this method repairs subsidence problems in in-service asphalt pavements caused by localized insufficient compaction of the roadbed. The multi-modified polymer crushed stone piles comprise component A, component B, and graded crushed stone. Component A contains 100 parts of polyol, 1.5-2 parts of stabilizer, 1-2 parts of small molecule chain extender / crosslinker, 2-5 parts of epoxy resin, 8-12 parts of organosilicon, 0.8-1 part of foaming agent, and 0.3-0.5 parts of catalyst. Component B contains 110-120 parts of isocyanate and 0.5-0.8 parts of flame retardant. The graded crushed stone comprises 900-1450 parts.

[0007] Preferably, the polyol is a polyether polyol, which is the polymer matrix of the crushed stone pile and reacts with isocyanate to produce polyurethane.

[0008] Preferably, the small molecule chain extender / crosslinker is 1,4-butanediol, which reacts with the NCO group of isocyanate to produce carbamate, thereby playing a chain-extending role.

[0009] Preferably, the stabilizer is dimethyl silicone oil, the epoxy resin is bisphenol A glycidyl ether, the organosilicon is γ-aminopropyltriethoxysilane, the foaming agent is sodium fatty alcohol polyoxyethylene ether sulfate, the catalyst is dibutyltin dilaurate, the isocyanate is polyphenylmethane polyisocyanate, and the flame retardant is a phosphorus-nitrogen flame retardant.

[0010] Preferably, the preparation method of the multi-modified polymer crushed stone pile includes the following steps:

[0011] (1) Weigh each raw material component of components A and B and graded crushed stone according to the mass ratio and set aside;

[0012] (2) In a container filled with polyol, add stabilizer, small molecule chain extender and crosslinker, epoxy resin, organosilicon, foaming agent and catalyst in sequence, and stir thoroughly at 25℃±5℃ to make the added reagents evenly dispersed in the polyol solvent to obtain component A.

[0013] (3) Add flame retardant to the container containing isocyanate to obtain component B;

[0014] (4) Add component A and component B to the device containing graded crushed stone at the same time. Component A and component B react fully in the gaps of the graded crushed stone and expand and solidify rapidly, cementing large-diameter graded crushed stone particles and filling pores to form a pile with stable structure and high compressive strength.

[0015] Preferably, the graded crushed stone is basalt with a particle size range of 16–31.5 mm, and its gradation range is as follows: pore size 37.5 mm, 100% throughput; pore size 31.5 mm, 90–100% throughput; pore size 26.5 mm, 50–90% throughput; pore size 19 mm, 20–50% throughput; pore size 16 mm, 10–25% throughput; pore size 9.5 mm, 4–12% throughput.

[0016] The advantages and positive effects of the multi-modified polymer crushed stone pile treatment method for localized asphalt pavement subsidence described in this invention are as follows:

[0017] 1. Waterproof, unaffected by humid environments, and highly adaptable; capable of rapid reaction expansion and curing, reaching 90% of its final strength within 15 minutes; environmentally friendly and resistant to microbial erosion.

[0018] 2. It has high expansibility, which compacts the soil and increases the bearing capacity of the surrounding soil.

[0019] 3. It has good elasticity and high compressive strength, and can use the adhesive properties of polymers to bind crushed stone together to form a complete whole, becoming a new type of pile body, overcoming the shortcomings of loose piles and facilitating construction.

[0020] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0021] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0022] A method for treating localized subsidence of asphalt pavement using multi-modified polymer crushed stone piles is proposed. This method utilizes the expansibility of multi-modified polymer crushed stone piles and the performance of graded crushed stone used as a retaining ring to compact the soil, reinforce the roadbed, and repair the subsidence problem caused by localized inadequate filling of the roadbed in in-service asphalt pavement. The multi-modified polymer crushed stone piles include component A, component B, and graded crushed stone.

[0023] Example 1

[0024] The preparation method of multi-modified polymer crushed stone piles includes the following steps:

[0025] (1) Weigh the raw materials and graded crushed stone of components A and B according to the mass ratio and set aside. The mixture consists of 100 parts polyether polyol, 2 parts dimethyl silicone oil as stabilizer, 2 parts 1,4-butanediol as a small molecule chain extender and crosslinking agent, 2 parts bisphenol A propane glycidyl ether as epoxy resin, and organosilicon... Prepare materials including 8 parts of aminopropyltriethoxysilane (KH-550), 1 part of foaming agent sodium fatty alcohol polyoxyethylene ether sulfate (AES), 0.5 parts of catalyst dibutyltin dilaurate, 115 parts of polyphenylmethane polyisocyanate, 0.5 parts of phosphorus-nitrogen flame retardant, and 1400 parts of graded crushed stone.

[0026] (2) In a container filled with polyether polyol, add dimethyl silicone oil, 1,4-butanediol, bisphenol A propane glycidyl ether, and other components in sequence. Aminopropyltriethoxysilane (KH-550), sodium fatty alcohol polyoxyethylene ether sulfate (AES), and dibutyltin dilaurate were stirred thoroughly at 25℃±5℃ to ensure that the added reagents were uniformly dispersed in the polyol solvent, thus obtaining component A.

[0027] (3) Add a phosphorus-nitrogen flame retardant to a container containing polyphenylmethane polyisocyanate to obtain component B;

[0028] (4) Add component A and component B to the device containing graded crushed stone at the same time. Component A and component B react fully in the gaps of the graded crushed stone and expand and solidify rapidly to form a polymer crushed stone pile specimen with a height of 300 mm and a diameter of 150 mm.

[0029] The graded crushed stone is basalt with a particle size range of 16 to 31.5 mm, and its gradation range is shown in Table 1.

[0030] Table 1. Passing Rate of Graded Crushed Stone

[0031]

[0032] The epoxy resin is bisphenol A propane glycidyl ether, which increases the compressive strength and bond strength of the polymer, and improves the polymer's corrosion resistance, heat resistance, and toughness; the organosilicon is... Aminopropyltriethoxysilane (KH-550) enhances the mechanical properties, water resistance, and heat resistance of polymers, and reduces the overall heat loss rate. The foaming agent is sodium fatty alcohol polyoxyethylene ether sulfate (AES), which generates a large number of bubbles during the chemical reaction, increasing the expansion rate of the polymer. The catalyst is dibutyltin dilaurate, which increases the chemical reaction rate between the polyol and isocyanate. The stabilizer is dimethyl silicone oil, which maintains chemical equilibrium, reduces surface tension, and prevents photo-, thermal, or oxidative decomposition. The small-molecule chain extender / crosslinker is 1,4-butanediol, which reacts with the NCO groups of isocyanate to produce urethane, thus extending the chain. The flame retardant is a phosphorus-nitrogen flame retardant, an intumescent flame retardant. When polymers containing this type of flame retardant are heated, a uniform carbonaceous foam layer can form on the surface, providing heat insulation, oxygen barrier, and smoke suppression, while preventing dripping and exhibiting excellent flame retardant properties.

[0033] Example 2

[0034] The preparation of epoxy resin modified polymer crushed stone piles includes the following steps:

[0035] (1) Prepare materials according to the following formula: 108 parts of polyether polyol, 2 parts of stabilizer dimethyl silicone oil, 2 parts of small molecule chain extender crosslinking agent 1,4-butanediol, 2 parts of epoxy resin bisphenol A propane glycidyl ether, 1 part of foaming agent fatty alcohol polyoxyethylene ether sodium sulfate (AES), 0.5 parts of catalyst dibutyltin dilaurate, 115 parts of polyphenylmethane polyisocyanate, 0.5 parts of phosphorus-nitrogen flame retardant, and 1400 parts of graded crushed stone;

[0036] (2) In a container containing polyether polyol, add dimethyl silicone oil, 1,4-butanediol, diphenol propane glycidyl ether, sodium fatty alcohol polyoxyethylene ether sulfate (AES), and dibutyltin dilaurate in sequence, and stir thoroughly at 25℃±5℃ to make the added reagents evenly dispersed in the polyol solvent to obtain component A.

[0037] (3) Add a phosphorus-nitrogen flame retardant to a container containing polyphenylmethane polyisocyanate to obtain component B;

[0038] (4) Add component A and component B to the device containing graded crushed stone at the same time. Component A and component B react fully in the gaps of the graded crushed stone and expand and solidify rapidly to form a polymer crushed stone pile specimen with a height of 300 mm and a diameter of 150 mm.

[0039] Example 3

[0040] The preparation of organosilicon-modified polymer crushed stone piles includes the following steps:

[0041] (1) 102 parts polyether polyol, 2 parts dimethyl silicone oil as stabilizer, 2 parts 1,4-butanediol as small molecule chain extender and crosslinker, and organosilicon Prepare materials including 8 parts of aminopropyltriethoxysilane (KH-550), 1 part of foaming agent sodium fatty alcohol polyoxyethylene ether sulfate (AES), 0.5 parts of catalyst dibutyltin dilaurate, 115 parts of polyphenylmethane polyisocyanate, 0.5 parts of phosphorus-nitrogen flame retardant, and 1400 parts of graded crushed stone.

[0042] (2) In a container filled with polyether polyol, add dimethyl silicone oil, 1,4-butanediol, and... Aminopropyltriethoxysilane (KH-550), sodium fatty alcohol polyoxyethylene ether sulfate (AES), and dibutyltin dilaurate were stirred thoroughly at 25℃±5℃ to ensure that the added reagents were uniformly dispersed in the polyol solvent, thus obtaining component A.

[0043] (3) Add a phosphorus-nitrogen flame retardant to a container containing polyphenylmethane polyisocyanate to obtain component B;

[0044] (4) Add component A and component B to the device containing graded crushed stone at the same time. Component A and component B react fully in the gaps of the graded crushed stone and expand and solidify rapidly to form a polymer crushed stone pile specimen with a height of 300 mm and a diameter of 150 mm.

[0045] Example 4

[0046] The preparation of ordinary polymer crushed stone piles includes the following steps:

[0047] (1) Prepare materials according to the following formula: 110 parts of polyether polyol, 2 parts of stabilizer dimethyl silicone oil, 2 parts of small molecule chain extender crosslinking agent 1,4-butanediol, 1 part of foaming agent sodium fatty alcohol polyoxyethylene ether sulfate (AES), 0.5 parts of catalyst dibutyltin dilaurate, 115 parts of polyphenylmethane polyisocyanate, 0.5 parts of phosphorus-nitrogen flame retardant, and 1400 parts of graded crushed stone;

[0048] (2) In a container containing polyether polyol, add dimethyl silicone oil, 1,4-butanediol, sodium fatty alcohol polyoxyethylene ether sulfate (AES), and dibutyltin dilaurate in sequence, and stir thoroughly at 25℃±5℃ to make the added reagents evenly dispersed in the polyol solvent to obtain component A.

[0049] (3) Add a phosphorus-nitrogen flame retardant to a container containing polyphenylmethane polyisocyanate to obtain component B;

[0050] (4) Add component A and component B to the device containing graded crushed stone at the same time. Component A and component B react fully in the gaps of the graded crushed stone and expand and solidify rapidly to form a polymer crushed stone pile specimen with a height of 300 mm and a diameter of 150 mm.

[0051] Example 5

[0052] The preparation method of multi-modified polymer crushed stone piles includes the following steps:

[0053] (1) Weigh the raw materials and graded crushed stone of components A and B according to the mass ratio and set aside. The mixture consists of 100 parts polyether polyol, 1.5 parts dimethyl silicone oil as stabilizer, 1 part 1,4-butanediol as a small molecule chain extender and crosslinking agent, 5 parts bisphenol A propane glycidyl ether as epoxy resin, and organosilicon... Prepare the following materials: 12 parts of aminopropyltriethoxysilane (KH-550), 0.8 parts of foaming agent sodium fatty alcohol polyoxyethylene ether sulfate (AES), 0.3 parts of catalyst dibutyltin dilaurate, 110 parts of polyphenylmethane polyisocyanate, 0.8 parts of phosphorus-nitrogen flame retardant, and 1000 parts of graded crushed stone.

[0054] (2) In a container filled with polyether polyol, add dimethyl silicone oil, 1,4-butanediol, bisphenol A propane glycidyl ether, and other components in sequence. Aminopropyltriethoxysilane (KH-550), sodium fatty alcohol polyoxyethylene ether sulfate (AES), and dibutyltin dilaurate were stirred thoroughly at 25℃±5℃ to ensure that the added reagents were uniformly dispersed in the polyol solvent, thus obtaining component A.

[0055] (3) Add a phosphorus-nitrogen flame retardant to a container containing polyphenylmethane polyisocyanate to obtain component B;

[0056] (4) Add component A and component B to the device containing graded crushed stone at the same time. Component A and component B react fully in the gaps of the graded crushed stone and expand and solidify rapidly to form a polymer crushed stone pile specimen with a height of 300 mm and a diameter of 150 mm.

[0057] Example 6

[0058] The preparation method of multi-modified polymer crushed stone piles includes the following steps:

[0059] (1) Weigh the raw materials and graded crushed stone of components A and B according to the mass ratio and set aside. The mixture consists of 100 parts polyether polyol, 1.8 parts dimethyl silicone oil as stabilizer, 1.5 parts 1,4-butanediol as a small molecule chain extender and crosslinking agent, 3 parts bisphenol A propane glycidyl ether as epoxy resin, and organosilicon... Prepare the following materials: 10 parts of aminopropyltriethoxysilane (KH-550), 0.9 parts of foaming agent sodium fatty alcohol polyoxyethylene ether sulfate (AES), 0.4 parts of catalyst dibutyltin dilaurate, 120 parts of polyphenylmethane polyisocyanate, 0.7 parts of phosphorus-nitrogen flame retardant, and 1200 parts of graded crushed stone.

[0060] (2) In a container filled with polyether polyol, add dimethyl silicone oil, 1,4-butanediol, bisphenol A propane glycidyl ether, and other components in sequence. Aminopropyltriethoxysilane (KH-550), sodium fatty alcohol polyoxyethylene ether sulfate (AES), and dibutyltin dilaurate were stirred thoroughly at 25℃±5℃ to ensure that the added reagents were uniformly dispersed in the polyol solvent, thus obtaining component A.

[0061] (3) Add a phosphorus-nitrogen flame retardant to a container containing polyphenylmethane polyisocyanate to obtain component B;

[0062] (4) Add component A and component B to the device containing graded crushed stone at the same time. Component A and component B react fully in the gaps of the graded crushed stone and expand and solidify rapidly to form a polymer crushed stone pile specimen with a height of 300 mm and a diameter of 150 mm.

[0063] Comparative Example

[0064] According to the test methods in the "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (JTG E51-2015), the mechanical properties of four types of polymer crushed stone piles in Examples 1-4 were tested, and the test results are shown in the table below.

[0065] Table 2 Mechanical properties of polymer crushed stone piles

[0066]

[0067] As shown in Table 2, the compressive strength of the multi-modified polymer crushed stone piles prepared in Example 1 is higher than that of the polymer crushed stone piles obtained in Examples 2 to 4. In Example 1, after the original solutions of components A and B undergo a chemical reaction, their volume expands rapidly and solidifies together with the graded crushed stone material, filling the pile hole from bottom to top, expanding and compacting the soil and rock on the hole wall, and fully combining with the surrounding soil and rock to form a polymer crushed stone pile. Epoxy resin and organosilicon improve the compressive strength of the polymer crushed stone pile.

[0068] Therefore, the present invention adopts the above-mentioned method for treating local subsidence of asphalt pavement using multi-modified polymer crushed stone piles. By utilizing the adhesive properties of polymers, crushed stone is bonded together to form a complete whole, which becomes a new type of pile body. This overcomes the disadvantages of loose piles and is convenient for construction.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for treating localized subsidence of asphalt pavement using multi-modified polymer crushed stone piles, utilizing the expansibility of multi-modified polymer crushed stone piles and the performance of their retaining graded crushed stone to compact the soil, reinforce the roadbed, and repair subsidence problems caused by localized inadequate compaction of the roadbed in in-service asphalt pavement, characterized in that: The multi-modified polymer crushed stone pile comprises component A, component B, and graded crushed stone. Component A contains 100 parts of polyol, 1.5-2 parts of stabilizer, 1-2 parts of small molecule chain extender / crosslinker, 2-5 parts of epoxy resin, 8-12 parts of organosilicon, 0.8-1 part of foaming agent, and 0.3-0.5 parts of catalyst. Component B contains 110-120 parts of isocyanate and 0.5-0.8 parts of flame retardant. The graded crushed stone comprises 900-1450 parts. The stabilizer is dimethyl silicone oil, the epoxy resin is bisphenol A glycidyl ether, and the organosilicon is... The foaming agent is sodium fatty alcohol polyoxyethylene ether sulfate, the catalyst is dibutyltin dilaurate, the isocyanate is polyphenylmethane polyisocyanate, and the flame retardant is a phosphorus-nitrogen flame retardant. The preparation method of the aforementioned multi-modified polymer crushed stone pile includes the following steps: (1) Weigh each raw material and graded crushed stone of components A and B according to the mass ratio and set aside; (2) In a container filled with polyol, add stabilizer, small molecule chain extender and crosslinker, epoxy resin, organosilicon, foaming agent and catalyst in sequence, and stir thoroughly at 25℃±5℃ to make the added reagents evenly dispersed in the polyol solvent to obtain component A. (3) Add flame retardant to the container containing isocyanate to obtain component B; (4) Add component A and component B to the device containing graded crushed stone at the same time. Component A and component B react fully in the gaps of the graded crushed stone and expand and solidify rapidly, cementing large-diameter graded crushed stone particles and filling pores to form a pile with stable structure and high compressive strength.

2. The method for treating localized subsidence of asphalt pavement using multi-modified polymer crushed stone piles according to claim 1, characterized in that: The polyol is a polyether polyol, which is the main polymer for multi-modified crushed stone piles. It reacts with isocyanate to produce polyurethane.

3. The method for treating localized subsidence of asphalt pavement using multi-modified polymer crushed stone piles according to claim 1, characterized in that: The small molecule chain extender and crosslinker is 1,4-butanediol, which reacts with the NCO group of isocyanate to produce carbamate, thereby playing a chain-extending role.

4. The method for treating localized subsidence of asphalt pavement using multi-modified polymer crushed stone piles according to claim 1, characterized in that: The graded crushed stone is basalt with a particle size range of 16–31.5 mm, and its gradation range is as follows: 37.5 mm pore size, 100% throughput; 31.5 mm pore size, 90–100% throughput; 26.5 mm pore size, 50–90% throughput; 19 mm pore size, 20–50% throughput; 16 mm pore size, 10–25% throughput; 9.5 mm pore size, 4–12% throughput.

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