Roadbed grouting material and preparation method thereof

Abstract

The application discloses a kind of roadbed grouting material and preparation method thereof, belong to grouting material technical field.The roadbed grouting material is composed of curing agent and additive, wherein additive is modified polyurethane, the modified polyurethane is by isocyanate, polyether polyol and epoxy resin are mixed according to mass ratio (3-8) :(12-17) :(10-20) Formed.The application is by the condensation reaction of isocyanate and polyether polyol two monomers to generate the polyurethane that can be used as grouting reinforcement material, break the original system after polyether polyol is added to epoxy resin system, by strictly controlling the amount of raw material, so that it can effectively improve product performance after combination, finally with polyether polyol and epoxy resin as co-modified material and prepared polyurethane are mixed, by crosslinking make polyurethane molecule proper network, improve the mechanical properties and stability of product.

Description

Technical Field

[0001] This invention belongs to the field of grouting materials technology, and particularly relates to a roadbed grouting material and its preparation method. Background Technology

[0002] The roadbed is the foundation of a road and a key factor in ensuring pavement quality. However, under the repeated action of various loads and natural factors, the roadbed can change shape. In particular, when the roadbed is exposed to water, it can develop defects such as the collapsibility of loess, the disintegration of red mudstone when exposed to water, and the erosiveness of saline soil. These defects can lead to roadbed subsidence, cracks, and other problems, seriously affecting the quality and stability of the pavement.

[0003] Grouting technology primarily involves injecting grout into underground engineering or road base layers using hydraulic or pneumatic methods to enhance their strength, impermeability, and stability, thereby improving the relevant mechanical properties of the underground engineering or road base layers. Grouting technology effectively solves the drawbacks of current roadbed repair processes, which require steps such as pavement removal, waste removal, material replenishment, and compaction, resulting in complex construction, traffic disruption, time-consuming and labor-intensive processes, and high economic costs. In grouting technology, the grouting material is crucial. To achieve excellent improvement results, the grouting material should possess good fluidity, strength, and stability.

[0004] Currently, common grouting materials in the highway field include cement-based grouting materials, polymer grouting materials, and geopolymer grouting materials. However, cement-based grouting materials have poor crack resistance, and micro-cracks easily appear in the bond between cement and aggregate during the hardening process. Although the porosity problem is solved after grouting with polymer grouting materials, the defects may continue to develop over time, resulting in porosity again. The polymer material cannot expand to fill these defects, leading to repair failure. Geopolymer grouting materials have low early strength due to the slow release of the potential activity of steel slag, blast furnace slag, and fly ash. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention proposes a roadbed grouting material and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A roadbed grouting material, the roadbed grouting material is composed of a curing agent and an additive, wherein the additive is a modified polyurethane, the modified polyurethane includes isocyanate, polyether polyol and epoxy resin, and the mass ratio of isocyanate, polyether polyol and epoxy resin is (3-8):(12-17):(10-20).

[0008] Furthermore, the isocyanate is toluene diisocyanate or diphenylmethane diisocyanate.

[0009] Furthermore, the polyether polyol is one or more of POP2045, 3050, or 410.

[0010] Polyurethane contains a large number of polar groups such as urethane groups and urea ether bonds, which can bond with soil and mineral particles to form an integral structure, thus playing a role in water plugging and improving the strength of the roadbed. Furthermore, in the relatively closed soil particle and grout mixture system, the carbon dioxide gas released during the solidification reaction generates significant internal pressure, propelling the grout to penetrate further, filling more porous structures or voids, and enhancing the water-plugging effect. The greater the restriction on the grout expansion process, the denser the resulting solidified body, and the higher its impermeability and compressive strength.

[0011] Furthermore, the epoxy resin is one or both of phenolic epoxy resin and alicyclic epoxy resin.

[0012] Epoxy resin materials possess advantages such as high strength, low shrinkage, strong adhesion, good chemical stability, room temperature curing, resistance to damp heat, good water resistance, and freeze-thaw resistance. This invention selects phenolic epoxy resin and alicyclic epoxy resin with functional groups as raw materials, which not only increases the crosslinking density of the cured product but also provides excellent physical and mechanical properties, while simultaneously improving weather resistance.

[0013] Further, based on parts by weight, the modified polyurethane comprises the following components: 3-8 parts isocyanate, 12-17 parts polyether polyol, 10-20 parts epoxy resin, 0.01-0.03 parts catalyst, 0.4-0.7 parts plasticizer, 0.9-1.1 parts diluent, and 5-15 parts acetone.

[0014] Further, the catalyst is triethanolamine or triethylamine; the plasticizer is a mixture of dioctyl terephthalate (DOTP) and dioctyl phthalate (DOP) in a mass ratio of 1:(0.1-0.4); the plasticizer has advantages such as good electrical properties and cold resistance, low volatility, and high plasticizing performance. This invention uses a special ratio of dioctyl terephthalate and dioctyl phthalate as a plasticizer, which can reduce material viscosity, increase product flexibility, reduce hardness, and reduce brittleness. The diluent is dimethyl phthalate.

[0015] Furthermore, the method for preparing the modified polyurethane is as follows:

[0016] 1) Mix isocyanate and diluent and stir at 50-60℃ for 35-40 min. Then add a portion of polyether polyol and continue heating to 65-75℃ and hold for 50-68 min to obtain mixture A.

[0017] 2) Mix the remaining polyether polyol with epoxy resin, add catalyst, diluent and acetone, and stir at 240-360 rpm for 10-18 min to obtain mixture B;

[0018] 3) Mix mixture A, mixture B and plasticizer together and stir at 35-40℃ and 600-730rpm for 1-3 minutes to obtain modified polyurethane.

[0019] Furthermore, the mass ratio of curing agent to modified polyurethane in the roadbed grouting material is 1:(0.1-0.5), and the curing agent is sodium silicate.

[0020] The present invention also provides a method for preparing the roadbed grouting material, wherein the raw materials are weighed by mass, the curing agent and the modified polyurethane are mixed in a mass ratio, and stirred at a speed of 450-600 rpm for 1-3 minutes to obtain the roadbed grouting material.

[0021] Compared with the prior art, the present invention has the following advantages and technical effects:

[0022] This invention uses isocyanate and polyether polyol as two monomers to generate polyurethane that can be used as a grouting reinforcement material through a polycondensation reaction. After adding polyether polyol to the epoxy resin system, the original system is broken. By strictly controlling the amount of raw materials, the combination of the two can effectively improve the impermeability and compressive strength of the product. Finally, polyether polyol and epoxy resin are used as co-modifying materials and mixed with the prepared polyurethane. Through crosslinking, the polyurethane molecules are appropriately networked, which improves the mechanical properties and stability of the product. Detailed Implementation

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0024] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0025] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0026] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0027] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0028] All raw materials used in the following embodiments of the present invention are commercially available.

[0029] Unless otherwise specified, the "parts" mentioned in this invention are all measured in "mass".

[0030] This invention provides a roadbed grouting material, which is composed of a curing agent and an additive, wherein the additive is a modified polyurethane, which comprises isocyanate, polyether polyol, and epoxy resin, and the mass ratio of isocyanate, polyether polyol, and epoxy resin is (3-8):(12-17):(10-20). In some preferred embodiments, the mass ratio of the three raw materials is (3-6):(13-16):(12-18).

[0031] In some preferred embodiments, the isocyanate is toluene diisocyanate or diphenylmethane diisocyanate. Isocyanates contain highly unsaturated isocyanate groups, thus exhibiting relatively high chemical reactivity and reactivity with polyether polyols.

[0032] In some preferred embodiments, the polyether polyol is one or more of POP2045, 3050, or 410. The specific combination is not limited in this invention; however, considering both cost and performance, this invention uses a mixture of POP2045, 3050, and 410 in a mass ratio of 2:1:1 as the polyether polyol raw material, resulting in a product with superior performance.

[0033] In this invention, during the reaction of isocyanate and polyether polyol to generate polyurethane, a large number of polar groups such as urethane groups and urea ether bonds are generated. These groups adhere to soil and mineral particles, forming an integral structure that functions to plug water and improve roadbed strength. Furthermore, in the relatively closed soil particle and grout mixture system, the carbon dioxide gas released during the reaction generates significant internal pressure, propelling the grout to penetrate further, filling more porous structures or voids, and enhancing the water-plugging effect. The greater the restriction on the grout expansion process, the denser the resulting solidified body, and the higher its impermeability and compressive strength.

[0034] In some preferred embodiments, the epoxy resin of this invention is one or both of phenolic epoxy resin and alicyclic epoxy resin. Epoxy resin materials have advantages such as high strength, low shrinkage, strong adhesion, good chemical stability, room temperature curing, resistance to damp heat, good water resistance, and freeze-thaw resistance. This invention selects phenolic epoxy resin and alicyclic epoxy resin with functional groups as raw materials, which not only increases the crosslinking density of the product after curing but also provides good physical and mechanical properties and improves weather resistance. Considering both cost and effectiveness, this invention selects a 1:1 mass ratio of phenolic epoxy resin and alicyclic epoxy resin as the epoxy resin to obtain a finished product with better performance.

[0035] It should be further explained that the grouting material prepared by this invention has good fluidity and low adhesion, which is beneficial as a grouting material. Epoxy resin materials themselves have good adhesion, which can effectively improve the heat resistance of the material, but does not have a significant impact on fluidity. To ensure that the fluidity meets the requirements of the grouting material, it is necessary to reasonably control the amount of each raw material.

[0036] In some preferred embodiments, the modified polyurethane comprises, by weight parts: 3-8 parts isocyanate, 12-17 parts polyether polyol, 10-20 parts epoxy resin, 0.01-0.03 parts catalyst, 0.4-0.7 parts plasticizer, 0.9-1.1 parts diluent, and 5-15 parts acetone. More preferably, it comprises 3-6 parts isocyanate, 13-16 parts polyether polyol, 12-18 parts epoxy resin, 0.01-0.02 parts catalyst, 0.4-0.6 parts plasticizer, 0.9-1.0 parts diluent, and 7-12 parts acetone.

[0037] In some preferred embodiments, the catalyst is triethanolamine or triethylamine; the plasticizer is a mixture of dioctyl terephthalate (DOTP) and dioctyl phthalate (DOP) in a mass ratio of 1:(0.1-0.4); the plasticizer has advantages such as good cold resistance, low volatility, and high plasticizing performance. This invention uses a special ratio of dioctyl terephthalate and dioctyl phthalate as a plasticizer, which can reduce material viscosity, increase product flexibility, reduce hardness, and reduce brittleness. The diluent is dimethyl phthalate.

[0038] In some preferred embodiments, the modified polyurethane is prepared by:

[0039] 1) Mix isocyanate and diluent and stir at 50-60℃ for 35-40 min. Then add a portion of polyether polyol and continue heating to 65-75℃ and hold for 50-68 min to obtain mixture A.

[0040] 2) Mix the remaining polyether polyol with epoxy resin, add catalyst, diluent and acetone, and stir at 240-360 rpm for 10-18 min to obtain mixture B;

[0041] 3) Mix mixture A, mixture B and plasticizer together and stir at 35-40℃ and 600-730rpm for 1-3 minutes to obtain modified polyurethane.

[0042] The mass ratio of the polyether polyols used in steps 1) and 2) is 1:1.2.

[0043] In some preferred embodiments, the mass ratio of curing agent to modified polyurethane in the roadbed grouting material is 1:(0.1-0.5), and the curing agent is sodium silicate. The main component of hardened sodium silicate is silicate solid, which has a large specific surface area and therefore high adhesive strength, improving the adhesion between raw materials. Furthermore, when combined with polyurethane, it can further enhance the performance of the modified polyurethane.

[0044] The present invention also provides a method for preparing the roadbed grouting material, wherein the raw materials are weighed by mass, the curing agent and the modified polyurethane are mixed in a mass ratio, and stirred at a speed of 450-600 rpm for 1-3 minutes to obtain the roadbed grouting material.

[0045] The following embodiments are further illustrations of the technical solution of the present invention.

[0046] Examples 1-6

[0047] The raw materials and quantities used in Examples 1-6 are shown in Table 1.

[0048] Table 1. Components and their dosage (parts)

[0049]

[0050] The preparation method of roadbed grouting material is as follows:

[0051] 1) Mix isocyanate and diluent and stir at 55°C for 38 min. Then add a portion of polyether polyol and continue heating to 70°C and hold for 60 min to obtain mixture A.

[0052] 2) Mix the remaining polyether polyol with epoxy resin, add catalyst, diluent and acetone, and stir at 300 rpm for 15 min to obtain mixture B;

[0053] 3) Mix mixture A, mixture B and plasticizer, and stir at 40℃ and 650 rpm for 2 minutes to obtain modified polyurethane;

[0054] 4) Mix sodium silicate and modified polyurethane at a mass ratio of 1:0.3 and stir at 500 rpm for 1.5 min to obtain the roadbed grouting material.

[0055] The mass ratio of the polyether polyols used in steps 1) and 2) is 1:1.2.

[0056] Example 7

[0057] Same as Example 1, except that sodium silicate and modified polyurethane are mixed in a mass ratio of 1:0.1.

[0058] Example 8

[0059] The raw material formula is the same as in Example 1.

[0060] The preparation method of roadbed grouting material is as follows:

[0061] 1) Mix isocyanate and diluent and stir at 60°C for 35 min. Then add a portion of polyether polyol and continue heating to 65°C and hold for 68 min to obtain mixture A.

[0062] 2) Mix the remaining polyether polyol with epoxy resin, add catalyst, diluent and acetone, and stir at 240 rpm for 18 min to obtain mixture B;

[0063] 3) Mix mixture A, mixture B and plasticizer, and stir at 40℃ and 730 rpm for 1 min to obtain modified polyurethane;

[0064] 4) Mix sodium silicate and modified polyurethane at a mass ratio of 1:0.3 and stir at 500 rpm for 1.5 min to obtain the roadbed grouting material.

[0065] The mass ratio of the polyether polyols used in steps 1) and 2) is 1:1.2.

[0066] Comparative Example 1

[0067] Same as Example 1, except that no epoxy resin is added.

[0068] Comparative Example 2

[0069] Same as Example 1, except that sodium silicate and modified polyurethane are mixed in a mass ratio of 1:1.

[0070] Comparative Example 3

[0071] Same as Example 6, except that the mass ratio of isocyanate, polyether polyol and epoxy resin is 1:1:1, that is, the modified polyurethane components are as follows: 8 parts isocyanate, 8 parts polyether polyol, 8 parts epoxy resin, 0.02 parts catalyst, 0.4 parts plasticizer, 1.1 parts diluent and 7 parts acetone.

[0072] Performance Test 1:

[0073] The viscosity, compressive strength, elongation at break, and impermeability pressure of the roadbed grouting materials obtained in Examples 1-8 and Comparative Examples 1-3 were tested using the following methods:

[0074] Viscosity and compressive strength shall be tested in accordance with the "JCT2041-2010 Polyurethane Grouting Materials" standard.

[0075] Elongation at break and impermeability pressure shall be tested in accordance with JC / T1041-2007.

[0076] Table 2. Performance test results of the examples and comparative examples.

[0077] Viscosity / mPa·s Compressive strength / MPa Elongation at break / % Anti-permeability pressure / % Example 1 240 84 110 2.1 Example 2 264 76 104 1.9 Example 3 271 78 106 2.0 Example 4 252 80 107 2.0 Example 5 244 82 109 2.1 Example 6 297 68 94 1.7 Example 7 242 83 109 2.1 Example 8 244 81 107 2.0 Comparative Example 1 320 55 92 1.4 Comparative Example 2 249 77 96 1.6 Comparative Example 3 314 58 93 1.5

[0078] As shown in Table 2, the roadbed grouting materials obtained in Examples 1-8 have a viscosity of 240-297 mPa·s, a compressive strength of 68-84 MPa, an elongation at break of 94-110%, and a seepage resistance of 1.7-2.1%. This indicates that the roadbed grouting materials obtained in this invention have low viscosity, good compressive strength, elasticity, and water-proofing ability. It is particularly important to note that the amount of modified polyurethane added to the roadbed grouting material is neither better the more nor the less. As seen in Examples 7 and 2, both increasing and decreasing the amount of modified polyurethane reduces the performance of the grouting material. Compared to Example 6, Comparative Example 3 only changed the ratio of isocyanate, polyether polyol, and epoxy resin, yet the roadbed performance also decreased significantly. This demonstrates that this ratio is a key factor affecting roadbed performance, and not any arbitrary ratio can achieve the same effect.

[0079] Performance Test 2:

[0080] The grouting materials prepared in the above embodiments and comparative examples were subjected to freeze-thaw tests according to the method in the "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering" (JTGE51-2009). The free expansion rate of the grouting materials was tested according to the free expansion rate test method in Appendix C4 of the "Technical Specification for Construction of Highway Bridges and Culverts" (JTG-TF50-2011). The expansion rate after ten freeze-thaw cycles was measured, and the results are shown in Table 3.

[0081] Table 3

[0082] 10-time freeze-thaw expansion rate / % Example 1 0.8 Example 2 1.1 Example 3 1.2 Example 4 1.0 Example 5 0.9 Example 6 1.3 Example 7 0.9 Example 8 0.8 Comparative Example 1 1.6 Comparative Example 2 1.0 Comparative Example 3 1.5

[0083] As can be seen from Table 3, the expansion rate of the roadbed grouting material prepared in the embodiments of the present invention is between 0.8% and 1.3% after ten freeze-thaw cycles, indicating that the roadbed grouting material prepared using the formula of the present invention has high stability.

[0084] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A roadbed grouting material, characterized in that, Modified polyurethane is used as an admixture in roadbed grouting material. The modified polyurethane includes isocyanate, polyether polyol and epoxy resin, and the mass ratio of isocyanate, polyether polyol and epoxy resin is (3-8):(12-17):(10-20). The modified polyurethane comprises the following components by weight: 3-8 parts isocyanate, 12-17 parts polyether polyol, 10-20 parts epoxy resin, 0.01-0.03 parts catalyst, 0.4-0.7 parts plasticizer, 0.9-1.1 parts diluent, and 5-15 parts acetone. The catalyst is triethanolamine or triethylamine; the plasticizer is a mixture of dioctyl terephthalate and dioctyl phthalate in a mass ratio of 1:(0.1-0.4); the diluent is dimethyl phthalate. The mass ratio of curing agent to modified polyurethane in the roadbed grouting material is 1:(0.1-0.5), and the curing agent is sodium silicate.

2. The roadbed grouting material according to claim 1, characterized in that, The isocyanate is toluene diisocyanate or diphenylmethane diisocyanate.

3. The roadbed grouting material according to claim 1, characterized in that, The polyether polyol is one or more of POP2045, 3050 or 410.

4. The roadbed grouting material according to claim 1, characterized in that, The epoxy resin is one or both of phenolic epoxy resin and alicyclic epoxy resin.

5. The roadbed grouting material according to any one of claims 1-4, characterized in that, The modified polyurethane is prepared by: 1) Mix isocyanate and diluent and stir at 50-60℃ for 35-40 min. Then add a portion of polyether polyol and continue heating to 65-75℃ and hold for 50-68 min to obtain mixture A. 2) Mix the remaining polyether polyol with epoxy resin, add catalyst, diluent and acetone, and stir at 240-360 rpm for 10-18 min to obtain mixture B; 3) Mix mixture A, mixture B and plasticizer, and stir at 35-40℃ and 600-730rpm for 1-3 minutes to obtain modified polyurethane.

6. A method for preparing a roadbed grouting material as described in any one of claims 1-5, characterized in that, Weigh the raw materials according to the mass ratio, mix the curing agent and modified polyurethane according to the mass ratio, and stir at 450-600 rpm for 1-3 minutes to obtain the roadbed grouting material.

Images