Super-viscous emulsified asphalt, wearing layer prepared from super-viscous emulsified asphalt and construction method of wearing layer

Abstract

The invention belongs to the technical field of polymer materials, and discloses super-viscous emulsified asphalt which is composed of high-viscosity asphalt and emulsion of emulsified high-viscosity asphalt. The mass ratio of the high-viscosity asphalt to the emulsion is (60-70): (30-40); the high-viscosity asphalt is prepared from the following components in parts by mass: 100 parts of asphalt, 6 to 10 parts of thermoplastic elastomer SBS (Styrene Butadiene Styrene), 2 to 4 parts of aniline formaldehyde resin and 4 to 8 parts of acetic acid-3-methoxybutyl ester. The emulsion comprises the following components in parts by mass: 7-15 parts of an emulsifier, 2-4 parts of an emulsifying aid, 7-15 parts of hydrochloric acid and 100 parts of water; according to the super-viscous emulsified asphalt, the prepared super-viscous emulsified asphalt has excellent durability by utilizing the synergistic interaction among the SBS, the aniline formaldehyde resin and the acetic acid-3-methoxybutyl ester in the high-viscous asphalt and the better dissolving effect of the emulsifier in the emulsion on organic matters in the asphalt. Meanwhile, the invention further discloses a preparation method and application of the super-viscous emulsified asphalt, an emulsified asphalt wearing layer prepared based on the super-viscous emulsified asphalt and a construction method of the emulsified asphalt wearing layer.

Description

Technical Field

[0001] The present invention belongs to the technical field of asphalt materials, and in particular relates to a super-viscous emulsified asphalt, a wearing layer made thereof, and a construction method. Background Art

[0002] Micro-surfacing, a commonly used preventive maintenance technique for highways, offers the advantages of cold construction and ultra-thin layer thickness. This means that instead of heating the asphalt mix in a mixing plant, emulsified asphalt is mixed with aggregate using a slurry sealer truck and then directly laid. Cold-mix cold paving offers significant advantages in terms of environmental protection, energy conservation, and emission reduction. Furthermore, the application thickness can be less than 1 cm, with a minimum of 6 mm, significantly thinner than the ultra-thin overlay of hot-mix asphalt (typically no less than 1 cm). Used for preventive maintenance on highways, micro-surfacing can minimize the impact on pavement elevation. Typical highway guardrail heights are 60 ± 2 cm. Some highway management departments, concerned that adding ultra-thin hot-mix overlays (1.2-1.5 cm) would reduce the guardrail-to-road elevation below 58 cm, have opted to mill the pavement, increasing construction costs. However, opting for a cold-mix cold paving process allows for a minimum layer thickness of 6 mm, significantly reducing the impact on guardrail height. In addition, emulsified asphalt is used in cold construction, which eliminates the asphalt heating and mixing process. From the perspective of energy conservation and carbon reduction, it is also a major trend in the future development of road maintenance.

[0003] However, conventional emulsified asphalt suffers from several drawbacks when used in cold-mix, cold-paving processes. First, it suffers from insufficient durability and a short service life. After a period of time, it begins to loosen, flake, and peel. This is primarily due to the poor performance of the emulsified asphalt materials used. The evaporation residue of conventional modified emulsified asphalt is typically ordinary modified asphalt, which exhibits low high-temperature and durability performance. Second, conventional modified emulsified asphalt exhibits poor adhesion, requiring the use of a high proportion of fine aggregate in the mixture gradation to constrain the coarse aggregate and stabilize the mixture structure. Typically, fine aggregates in the 0-3mm range account for a high proportion. Increasing the amount of fine aggregate can lead to a harder and more brittle mixture, which is detrimental to its durability. Furthermore, using too much fine aggregate reduces pavement comfort and increases driving noise. Since cold-mix, cold-paving emulsified asphalt is directly paved after mixing, without compaction, the pavement surface is less smooth, resulting in significant noise and jolts when vehicles pass over it. In addition, due to the large amount of fine aggregate used, the structural depth of the pavement surface is small, the pavement's anti-skid performance is low, and the anti-skid performance decays quickly.

[0004] Based on this, the problem to be solved by the present invention is: how to obtain a super-viscous emulsified asphalt with excellent durability, which is only combined with coarse aggregate. The obtained emulsified asphalt wearing layer has large gaps inside, a large surface macrostructure, long-lasting anti-skid performance, and excellent durability. Summary of the Invention

[0005] The object of the present invention is to provide a super-viscous emulsified asphalt, which is composed of high-viscosity asphalt and an emulsion of emulsified high-viscosity asphalt. The super-viscous emulsified asphalt has excellent durability by utilizing the synergistic effect between SBS, aniline formaldehyde resin, and 3-methoxybutyl acetate in the high-viscosity asphalt, and the better solubility of the emulsifier in the emulsion on the organic matter in the asphalt.

[0006] At the same time, the present invention also provides a preparation method of the super-viscous emulsified asphalt, a wearing layer prepared by using the emulsified asphalt, and a construction method.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A super-viscous emulsified asphalt, the super-viscous emulsified asphalt consisting of high-viscous asphalt and an emulsion of emulsified high-viscous asphalt; the mass ratio of the high-viscous asphalt to the emulsion is 60-70:30:40;

[0009] The high-viscosity asphalt comprises, by weight, 100 parts of asphalt, 6-10 parts of thermoplastic elastomer SBS, 2-4 parts of aniline formaldehyde resin, and 4-8 parts of 3-methoxybutyl acetate; the emulsion comprises, by weight, 7-15 parts of emulsifier, 2-4 parts of emulsifying aid, 7-15 parts of hydrochloric acid, and 100 parts of water.

[0010] In some existing technologies, SBS is the most commonly used modifier in modified asphalt. Its larger molecular chain plays a supporting role in asphalt, which improves the tensile strength and elastic properties of asphalt. However, during the processing of ordinary modified asphalt, sulfur stabilizers are generally added for cross-linking to ensure the stability of SBS in the asphalt. Otherwise, SBS is prone to aggregation in a fluid state. However, after adding stabilizers, asphalt is more difficult to emulsify. If no stabilizer is added, SBS is prone to aggregation, which is not conducive to emulsification.

[0011] In this invention, the innovative use of aniline formaldehyde resin is characterized by its inability to undergo cross-linking reactions after heating. When heated and mixed with SBS, it forms a cross-linked microstructure with the SBS molecular chains. This structure is relatively stable and does not undergo cross-linking reactions, which makes the asphalt unaffected during the emulsification process and maintains stable performance in a flowing state. 3-Methoxybutyl acetate is a solvent that is soluble in both water and organic solvents. In the production process of high-viscosity asphalt, the use of this solvent can accelerate the dissolution of SBS and aniline formaldehyde resin with the matrix asphalt, avoiding the phenomenon of modifier flocculation in high-viscosity asphalt. At the same time, it has good hydrophilicity during the emulsification process and can also accelerate the cutting of asphalt particles by water, completing emulsification.

[0012] Preferably, the emulsifier has the structure of Formula I:

[0013]

[0014] Preferably, R in the formula I is C 9～18 H 19～37 .

[0015] More preferably, the emulsifier consists of emulsifier 1 and emulsifier 2, and R in emulsifier 1 is C 18 H 37 , R in emulsifier 2 is C 9～11 H 19～23 ; The mass ratio of emulsifier 1 to emulsifier 2 is 50-70:30-50.

[0016] In further research of the present invention, it was found that since asphalt is a relatively complex organic matter with a molecular weight distribution ranging from several hundred to several hundred thousand, the carbon chain lengths in the corresponding molecular structures are different. During the emulsification process, the organic structural part (lipophilic group) of the emulsifier and the organic functional groups in the asphalt produce a weak chemical reaction between molecules (organic similarity is compatible, polar force) to attract each other. Since the molecular weight of the SBS used in high-viscosity asphalt ranges from tens of thousands to several hundred thousand, an emulsifier with more C atoms is required to produce a larger chemical force, thereby forming a stable structure. When the emulsifier 1 and emulsifier 2 selected by the present invention are used together, they can act on molecular chains of different lengths in high-viscosity asphalt respectively, with a synergistic effect. At the same time, both emulsifier 1 and emulsifier 2 have three side chains, which make them better in contact and compatible with the organic matter in the asphalt, and the emulsification efficiency is extremely high.

[0017] Preferably, the emulsifying aid is laurylamine oxide.

[0018] Dodecylamine oxide is a substance that can produce stable foam, which can improve the solubility between the components and thus enhance the overall stability of emulsified asphalt.

[0019] In addition, the present invention discloses a method for preparing the super-viscous emulsified asphalt as described above, comprising the following steps:

[0020] Step 1: Heat the asphalt to 180-190°C, add SBS and aniline formaldehyde resin in sequence, and after the SBS and aniline formaldehyde resin are completely melted, use a high-speed shearing machine to shear for 45-60 minutes. Then, reduce the temperature to 160°C, add 3-methoxybutyl acetate, and stir for 1 hour to produce high-viscosity asphalt;

[0021] Step 2: Heat water to 60-80°C, add emulsifier and emulsifying aid in proportion, stir evenly, measure the pH value of the emulsion, and then add hydrochloric acid until the pH value of the emulsion stabilizes at around 2 to obtain the emulsion;

[0022] Step 3: Heat the high-viscosity asphalt prepared in step 1 to 160°C, and heat the emulsion prepared in step 2 to 60-80°C. Then, control the flow rate of the two components in proportion and mix them. Then, grind them in a colloid mill. When the emulsified asphalt particle size is ground to 1-3μm, the emulsified asphalt is discharged through a heat exchanger at a discharge temperature of 50-60°C, and the preparation is completed.

[0023] In addition, the present invention discloses the use of the super-viscous emulsified asphalt as described above to prepare an emulsified asphalt wearing layer.

[0024] In addition, the present invention discloses an emulsified asphalt wearing layer, which contains, by mass, 14-20 parts of the super-viscous emulsified asphalt according to any one of claims 1 to 5, 100 parts of crushed stone, 0.1-1 part of fiber, 0.1-1 part of cement, and 0.5-2 parts of water.

[0025] Finally, the present invention also discloses a construction process for the emulsified asphalt wearing course as described above, which specifically includes the following steps:

[0026] Step 1: Spread tack coat oil on the original road surface;

[0027] Step 2: Pre-mix the crushed stone and fiber at the stockpile, then transport them to the construction site, and use a slurry sealer to evenly mix the pre-mixed crushed stone, emulsified asphalt, water, and cement in proportion. The mass ratio of the crushed stone, fiber, super-viscous emulsified asphalt, cement, and water is 100:0.1-1:0.1-1:0.5-2:14-20.

[0028] Step 3: Spread the product of step 2 on the tack coat of step 1. After spreading for 2 hours, use a rubber wheel to roll it 3-4 times and the construction is completed.

[0029] Preferably, the rock type of the crushed stone is basalt or diabase, and its specification is 3-7 mm; the fiber is one or a combination of polyester fiber, polyacrylonitrile fiber, and basalt fiber, and its length is 3 mm and its diameter is 12 μm; the cement is quick-drying acid salt cement.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The super-viscous emulsified asphalt of the present invention utilizes the synergistic effect between SBS, aniline formaldehyde resin and 3-methoxybutyl acetate in high-viscosity asphalt, and the emulsifier in the emulsion has a better solubility effect on the organic matter in the asphalt, so that the prepared super-viscous emulsified asphalt has excellent stability and durability.

[0032] 2. The emulsified asphalt wearing layer further prepared using the super-viscous emulsified asphalt of the present invention, based on the characteristics of the super-viscous emulsified asphalt itself, avoids the problem of excessive pores in the structure caused by the use of coarse aggregate of a single particle size in the traditional wearing layer. During the mixing process, the emulsified asphalt will flow down to the road surface, causing segregation of the mixture. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Product Information:

[0035] Asphalt: Esso 70# base asphalt, produced in Singapore, purchased from Dongguan Taihe Asphalt Plant;

[0036] Thermoplastic elastomer SBS: YH791-H produced by Sinopec Baling Petrochemical Plant;

[0037] Aniline formaldehyde resin: POE8452 produced by Du Pont Dow Elastomers, USA;

[0038] 3-Methoxybutyl acetate: 3-Methoxybutyl acetate produced by J&K Technology Co., Ltd., 98% (CAS No. 4435-53-4);

[0039] Emulsifier: Methyl tri-C18(C9-11)alkylammonium chloride purchased from the pilot plant of Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences;

[0040] Dodecylamine oxide: OA-12 produced by Harbin Jinma Additive Co., Ltd.

[0041] Part 1

[0042] The following examples and comparative examples are prepared as follows:

[0043] Step 1: Heat the asphalt to 185°C, add SBS and aniline formaldehyde resin in sequence, wait for the SBS and aniline formaldehyde resin to completely melt, use a high-speed shearing machine to shear for 50 minutes, then lower the temperature to 160°C, add 3-methoxybutyl acetate, and stir for 1 hour to produce high-viscosity asphalt;

[0044] Step 2: Heat water to 70°C, add emulsifier and emulsifying aid in proportion, stir evenly, measure the pH value of the emulsion, and then add hydrochloric acid until the pH value of the emulsion stabilizes at about 2 to obtain the emulsion;

[0045] Step 3: Heat the high-viscosity asphalt prepared in step 1 to 160°C, and heat the emulsion prepared in step 2 to 70°C. Then, control the flow rate of the two components in proportion to mix them, and then grind them in a colloid mill. When the emulsified asphalt particle size is ground to 2μm, the emulsified asphalt is discharged through a heat exchanger at a discharge temperature of 55°C, and the preparation is completed.

[0046] The formula table of each embodiment and comparative example is shown in Table 1.

[0047] Table 1 Super Viscous Emulsified Asphalt Formula (Parts by Mass)

[0048]

[0049] The mass ratio of high-viscosity asphalt to emulsion in the high-viscosity emulsified asphalts of Examples 1-8 and Comparative Examples 1-2 is 65:35;

[0050] The emulsifiers of Examples 1-3 consist of emulsifier 1 and emulsifier 2, wherein the mass ratio of emulsifier ① to emulsifier ② in Examples 1 and 2 is 50:50; the mass ratio of emulsifier 1 to emulsifier 2 in Example 3 is 70:30.

[0051] The emulsifier in Example 4 is emulsifier 1; the emulsifier in Example 5 is emulsifier 2;

[0052] The emulsifier in Comparative Example 1 is trimethyl emulsifier; its structural formula is shown in Formula II:

[0053]

[0054] Example 6

[0055] It is generally the same as Example 1, except that the mass ratio of high-viscosity asphalt to emulsion in the high-viscosity emulsified asphalt is 60:40.

[0056] Example 7

[0057] It is generally the same as Example 1, except that the mass ratio of high-viscosity asphalt to emulsion in the high-viscosity emulsified asphalt is 70:30.

[0058] Part 2

[0059] The super-viscous emulsified asphalt prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3, as well as crushed stone, fiber, cement, and water were used for construction to obtain an emulsified asphalt wearing layer. The specific construction method is as follows:

[0060] Step 1: Spread tack coat oil on the original road surface;

[0061] Step 2: Pre-mix the crushed stone and fiber at the stockpile, then transport them to the construction site. Use a slurry sealer to evenly mix the pre-mixed crushed stone, emulsified asphalt, water, and cement in proportion. The mass ratio of the crushed stone, fiber, cement, water, and super-viscous emulsified asphalt is 100:0.1-1:0.1-1:0.5-2:14-20.

[0062] Step 3: Spread the product of step 2 on the tack coat of step 1. After spreading for 2 hours, use a rubber-wheel roller to roll it 3-4 times. The construction is completed.

[0063] The emulsified asphalt wear layer corresponding to Example 1 is emulsified asphalt wear layer 1 and emulsified asphalt wear layer 2, the emulsified asphalt wear layer corresponding to Comparative Example 1 is emulsified asphalt wear layer 3, the emulsified asphalt wear layer corresponding to Comparative Example 2 is emulsified asphalt wear layer 4, and the emulsified asphalt wear layer corresponding to Comparative Example 3 is emulsified asphalt wear layer 5. The formula table of each emulsified asphalt wear layer is shown in Table 2.

[0064] Table 2 Emulsified asphalt wearing layer formula (parts by mass)

[0065] substance Wear layer 1 Wear layer 2 Wear layer 3 Wear layer 4 Wear layer 5 gravel 100 100 100 100 100 fiber 0.5 1 0.5 0.5 0.5 cement 0.5 1 0.5 0.5 0.5 Super sticky emulsified asphalt 14 20 14 14 14 water 1 2 1 1 1

[0066] Performance testing

[0067] The super-viscous emulsified asphalt and the emulsified asphalt wearing layer prepared in each embodiment and comparative example were subjected to the following tests:

[0068] Refer to "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" JTG E20-2011;

[0069] Emulsified asphalt testing |:

[0070] Storage stability: T 0655 1993;

[0071] Evaporation residue: T 0651 -1993;

[0072] Softening point: T 0606-2011;

[0073] 60℃ dynamic viscosity: T 0620 -2000;

[0074] Elastic recovery rate: T 0662-2000.

[0075] Emulsified asphalt wearing course test:

[0076] Kentucky Fort scattered loss: T0733-2011;

[0077] Void ratio: T 0708-2011.

[0078] The relevant test results are shown in Tables 3 and 4;

[0079] Table 3 shows the test results of super-viscous emulsified asphalt;

[0080] Table 3 Super viscous emulsified asphalt test data

[0081]

[0082] Analysis of the data in Table 3 shows that:

[0083] The data of Examples 1-7 show that the super-viscous emulsified asphalt prepared by the present invention has good stability, with a 24-hour storage stability between 0.1% and 0.9%, and a 120-hour storage stability between 0.4% and 2.4;

[0084] The emulsified asphalt prepared using trimethyl emulsifier in Comparative Example 1 had poor stability, with a 24-hour storage stability of 1.6% and a 120-hour storage stability of 4.7%. The reason for the poor stability was that the trimethyl emulsifier had only one branched chain, resulting in poor emulsification effect for high-viscosity asphalt.

[0085] The super-viscous emulsified asphalt of Comparative Example 2 lacks aniline formaldehyde resin in its high-viscosity asphalt, which causes SBS in the high-viscosity asphalt to aggregate during the emulsification process, significantly reduces the emulsification effect, and ultimately leads to poor stability.

[0086] The super-viscous emulsified asphalt of Comparative Example 3 lacks 3-methoxybutyl acetate in its high-viscosity asphalt, resulting in poor solubility of SBS and aniline formaldehyde resin in the high-viscosity asphalt with the matrix asphalt, causing flocculation, resulting in a decrease in emulsification effect and poor stability.

[0087] The super-viscous emulsified asphalt of the present invention is based on the synergistic effect between SBS, aniline formaldehyde resin and 3-methoxybutyl acetate, and the emulsifier in the emulsion has a better solubility effect on organic matter in the asphalt, so that the prepared super-viscous emulsified asphalt has excellent durability.

[0088] Table 4 shows the test results of the emulsified asphalt wearing layer;

[0089] Table 4 Emulsified asphalt wearing layer test data

[0090] Wear layer 1 Wear layer 2 Wear layer 3 Wear layer 4 Wear layer 5 Void ratio / % 24.7 23.8 22.6 22.8 24.1 Scattering loss / % 4.2 3.4 18.7 22.9 24.6

[0091] The data analysis of Table 4 shows that:

[0092] The emulsified asphalt wear layers 1-2 prepared using the super-viscous emulsified asphalt of Example 1 have porosities of 24.7% and 23.8%, respectively, and therefore have the functional characteristics of good drainage and noise reduction; their Kentucky Fort scattering loss rates are 4.2% and 3.4%, indicating excellent durability. However, the emulsified asphalt wear layers 3-5 prepared using the emulsified asphalt of Comparative Examples 1-3, although having similar porosities, have significantly increased Kentucky Fort scattering loss rates of 18.7%, 22.9%, and 24.6%, respectively, indicating poor anti-loosening durability. It is precisely because of the poor emulsification effect of the highly viscous asphalt and the poor storage stability of the emulsified asphalt that the emulsified asphalt wear layer undergoes segregation, resulting in unstable performance.

[0093] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A super-viscous emulsified asphalt, characterized in that: The super-viscous emulsified asphalt is composed of high-viscous asphalt and an emulsion of emulsified high-viscous asphalt; the mass ratio of the high-viscous asphalt to the emulsion is 60-70:30-40; The high-viscosity asphalt comprises, by weight, 100 parts of asphalt, 6-10 parts of thermoplastic elastomer SBS, 2-4 parts of aniline formaldehyde resin, and 4-8 parts of 3-methoxybutyl acetate; the emulsion comprises, by weight, 7-15 parts of emulsifier, 2-4 parts of emulsifying aid, 7-15 parts of hydrochloric acid, and 100 parts of water.

2. The super-viscous emulsified asphalt according to claim 1, characterized in that The emulsifier has the structure of formula I:

3. The super-viscous emulsified asphalt according to claim 2, characterized in that In the formula I, R is C 9～18 H 19～37 .

4. The super-viscous emulsified asphalt according to claim 2, characterized in that The emulsifier is composed of emulsifier 1 and emulsifier 2, and R in emulsifier 1 is C 18 H 37 , R in emulsifier 2 is C 9～11 H 19～23 ; The mass ratio of emulsifier 1 to emulsifier 2 is 50-70:30-50.

5. The super-viscous emulsified asphalt according to claim 1, characterized in that The emulsifying aid is laurylamine oxide.

6. A method for preparing super-viscous emulsified asphalt according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: Heat the asphalt to 180-190°C, add SBS and aniline formaldehyde resin in sequence, and after the SBS and aniline formaldehyde resin are completely melted, use a high-speed shearing machine to shear for 45-60 minutes. Then, reduce the temperature to 160°C, add 3-methoxybutyl acetate, and stir for 1 hour to produce high-viscosity asphalt; Step 2: Heat water to 60-80°C, add emulsifier and emulsifying aid in proportion, stir evenly, measure the pH value of the emulsion, and then add hydrochloric acid until the pH value of the emulsion stabilizes at around 2 to obtain the emulsion; Step 3: Heat the high-viscosity asphalt prepared in step 1 to 160°C, and heat the emulsion prepared in step 2 to 60-80°C. Then, control the flow rate of the two components in proportion and mix them. Then, grind them in a colloid mill. When the emulsified asphalt particle size is ground to 1-3μm, the emulsified asphalt is discharged through a heat exchanger at a discharge temperature of 50-60°C, and the preparation is completed.

7. Use of the super-viscous emulsified asphalt according to any one of claims 1 to 5 to prepare an emulsified asphalt wearing layer.

8. An emulsified asphalt wearing layer, characterized in that: Calculated by mass, it contains 14-20 parts of the super-viscous emulsified asphalt according to any one of claims 1 to 5, 100 parts of crushed stone, 0.1-1 part of fiber, 0.1-1 part of cement, and 0.5-2 parts of water.

9. A construction method for an emulsified asphalt wearing course according to claim 8, characterized in that: The specific steps include: Step 1: Spread tack coat oil on the original road surface; Step 2: Pre-mix the crushed stone and fiber at the stockpile, then transport them to the construction site. Use a slurry sealer to evenly mix the pre-mixed crushed stone, emulsified asphalt, water, and cement in proportion. The mass ratio of the crushed stone, fiber, cement, water, and super-viscous emulsified asphalt is 100:0.1-1:0.1-1:0.5-2:14-20. Step 3: Spread the product of step 2 on the tack coat of step 1. After spreading for 2 hours, use a rubber-wheel roller to roll it 3-4 times. The construction is completed.

10. The emulsified asphalt wearing layer according to claim 9, characterized in that: The rock type of the crushed stone is basalt or diabase, and its specification is 3-7mm; the fiber is one or a combination of polyester fiber, polyacrylonitrile fiber, and basalt fiber, and its length is 3mm and its diameter is 12μm; the cement is quick-drying silicate cement.

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