Sand-containing fog seal material and preparation method thereof

Abstract

The invention discloses a sand-containing fog seal material and a preparation method thereof, the sand-containing fog seal material comprises a glue solution, aggregate and auxiliaries, the glue solution is a mixture of water-based latex and emulsified asphalt, and the auxiliaries comprise a sodium pyrophosphate modified cellulose ether stabilizer, a dispersing agent, a reinforcing agent and a film-forming agent; the preparation method comprises the following steps: adding an auxiliary agent into a glue solution, and stirring to form a uniform mixed solution; and adding the aggregate into the mixed solution, and uniformly stirring. The bleeding rate of the sand-containing fog seal slurry in 24 hours is 0%, the surface can be dried after the material is sprayed to a pavement for half an hour, the bonding strength in three hours at 25 DEG C is 2.5-2.8 MPa, the bonding strength in three hours at 50 DEG C is 0.8-1.2 MPa, the wet wheel abrasion value is 21-26g / m < 2 >, the sand-containing fog seal slurry has the characteristics of short drying time, excellent high-temperature bonding property, good wear resistance, excellent stability and the like, and rapid traffic opening can be realized after the material is sprayed.

Description

Technical Field

[0001] This invention belongs to the field of road repair materials, and in particular relates to a sand-containing fog seal material and its preparation method. Background Technology

[0002] Most of my country's high-grade highways use asphalt concrete pavement. With long-term service, asphalt concrete pavement gradually develops fatigue cracking, aggregate loosening or falling off, decreased blackness, and reduced skid resistance due to traffic load, dynamic water pressure, asphalt aging, and other reasons. This leads to a gradual decline in the appearance of the pavement and driving comfort. If not repaired in time, the pavement will further develop more serious defects such as network cracking and potholes.

[0003] Sand-containing fog seal technology is a technique that uses specialized equipment with high pressure to spray fog seal mixture onto the surface of old roads to form a functional repair layer. This layer seals micro-cracks in the road surface, prevents loose aggregate from falling off, stops water infiltration, slows down asphalt aging, and improves the appearance of the road surface, as well as enhancing driving comfort and safety.

[0004] Pure emulsified asphalt-based sand-containing fog seal materials have poor high-temperature resistance, exhibiting decreased adhesion and poor abrasion resistance under high-temperature conditions. High-temperature resistant resins need to be added, but common high-temperature resistant resins are often two-component materials. These two-component materials require on-site mixing. If rain or other abnormal weather occurs before spraying, preventing normal construction, the mixed material becomes essentially unusable. Furthermore, this material needs timely cleaning from the equipment; if not cleaned promptly, it hardens and is difficult to handle. Existing technologies propose using a mixture of latex and emulsified asphalt to form an adhesive, addressing the drawback of on-site application for two-component materials. However, the density of this latex and emulsified asphalt mixture is relatively low, making it prone to aggregates in the slurry settling due to their higher density, leading to material segregation and stratification. Generally, the bleeding rate is measured after slurry preparation; slurries with a bleeding rate exceeding 1% do not meet construction standards. Using slurries with high bleeding rates as sand-containing fog seal materials will negatively impact subsequent pavement performance, resulting in low bond strength and high wet wheel abrasion.

[0005] Therefore, a sand-containing fog seal material with high slurry cohesion (i.e., low bleeding rate) and high adhesion to the road surface to be repaired is being developed. Summary of the Invention

[0006] Purpose of the invention: The technical problem to be solved by the present invention is to provide a sand-containing fog seal material with high slurry cohesion (i.e., low bleeding rate) and high adhesion to the road surface to be repaired, and a method for preparing the same.

[0007] Technical solution: The sand-containing fog sealing material of the present invention comprises the following raw materials in parts by weight: 40-60 parts of adhesive, 30-50 parts of aggregate and 5-10 parts of additives;

[0008] The adhesive is a mixture of water-based latex and emulsified asphalt in a mass ratio of (0.6:1) to (1:0.6);

[0009] The additives include 1-3 parts of sodium pyrophosphate modified cellulose ether stabilizer, 0.5-2 parts of dispersant, 2-5 parts of reinforcing agent, and 1.5-3 parts of film-forming agent.

[0010] Furthermore, the stabilizer used in the sand-containing fog sealing material of the present invention is prepared by the following method: sodium pyrophosphate is added to cellulose ether and stirred at a constant temperature of 40-60°C until a pale yellow liquid is formed; then the yellow liquid is washed until the pH value is 6-7 to obtain a stabilizer gel. Preferably, the mass ratio of cellulose ether to sodium pyrophosphate can be 1:(1-2).

[0011] Furthermore, the reinforcing agent used in the sand-containing fog sealing material of the present invention is prepared by the following method: calcium hydroxide powder is ground and then added to ethanol, and stirred evenly at room temperature; tetrabutyl titanate is added, and stirred at 30-50°C for 10-20 minutes, followed by drying. Preferably, the mass ratio of calcium hydroxide to ethanol is 1:(1-2); the amount of tetrabutyl titanate added is 0.1-0.3 times the mass of calcium hydroxide.

[0012] Preferably, the water-based latex used in the sand-containing fog seal material of the present invention is selected from one or more of silicone-acrylic latex, chloroprene latex, and styrene-acrylic latex; the emulsified asphalt is selected from one or more of SBR-modified emulsified asphalt, SBS-modified emulsified asphalt, EVA-modified emulsified asphalt, and rubber powder-modified emulsified asphalt.

[0013] Preferably, the aggregate used in the sand-containing fog sealing material of the present invention can be selected from one or more of 20-80 mesh silica powder, limestone powder, and alumina powder. The dispersant can be selected from one or more of octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, and dodecylamine polyoxyethylene ether. The film-forming agent can be selected from one or more of dodecyl alcohol ester, hexadecyl alcohol ester, and propylene glycol phenyl ether.

[0014] The method for preparing the above-mentioned sand-containing fog sealing material according to the present invention includes the following steps: adding additives to the adhesive solution and stirring to form a uniform mixture; adding aggregates to the mixture and stirring evenly.

[0015] Beneficial effects: Compared with the prior art, the significant advantages of this invention are: the water bleeding rate of the sand-containing mist seal slurry is 0% after 24 hours; the material dries to the surface within half an hour after being applied to the road surface; the bond strength is 2.5-2.8 MPa after three hours at 25℃; the bond strength is 0.8-1.2 MPa after three hours at 50℃; and the wet wheel abrasion value is 21-26 g / m. 2 It features short drying time, excellent high-temperature adhesion, good wear resistance and stability, and can quickly open to traffic after spraying. Attached Figure Description

[0016] Figure 1 This is a finished product image of the sand-containing fog seal material from Example 1;

[0017] Figure 2 This is a diagram showing the effect of the sand-containing fog seal material after curing in Example 1. Detailed Implementation

[0018] The technical solution of the present invention will be further described in detail below with reference to the embodiments and examples.

[0019] The preparation method of the stabilizer of the present invention is as follows: Hydroxypropyl methylcellulose ether is weighed and added to sodium pyrophosphate at a concentration of 0.2 g / ml, and the mixture is stirred for 6 min; then, the beaker is placed in a constant temperature magnetic stirrer set at 40℃ and stirred for 6 h to obtain a pale yellow liquid; finally, the liquid is centrifuged and washed until the pH value is 6 to obtain a colloid, which is the stabilizer. The mass ratio of hydroxypropyl methylcellulose to sodium pyrophosphate is 1:(1-2).

[0020] The preparation method of the reinforcing agent of the present invention is as follows: Calcium hydroxide is ground to 250 mesh, ethanol is added, and the mixture is stirred evenly. The mixture is placed in a reaction vessel and stirred at 500 r / min for 5 min at 25°C. Then, tetrabutyl titanate is added and stirred at 300 r / min for 20 min at 50°C. Finally, the mixture is removed and allowed to air dry naturally at room temperature to obtain the interface reinforcing agent. The mass ratio of calcium hydroxide to ethanol is 1:(1-2), and the amount of tetrabutyl titanate added is 0.1-0.3 times the mass of calcium hydroxide.

[0021] In the embodiments and comparative examples of this invention, each part by weight is 1 kg.

[0022] The main raw materials used in the following examples and comparative examples are shown in Table 1.

[0023] Table 1. Sources of Main Raw Materials

[0024]

[0025] Example 1

[0026] The composition and content of the sand-containing fog seal material in Example 1 are shown in Table 2 below.

[0027] Table 2. Raw material composition content of Example 1

[0028]

[0029] The preparation process of the sand-containing fog sealing material in Example 1 specifically includes the following steps:

[0030] (1) Mix stabilizer, dispersant, reinforcing agent and film-forming agent evenly to form an auxiliary agent;

[0031] (2) Mix silicone acrylic latex and SBR modified emulsified asphalt evenly, add additives, and stir to form a uniform mixture;

[0032] (3) Add the aggregate to the mixture and stir evenly to form a sand-containing fog seal material.

[0033] Comparative Example 1

[0034] The method for preparing the sand-containing spray seal material in Comparative Example 1 is the same as that in Example 1, the difference being the components and their contents in the raw materials. Specifically, hydroxypropyl methylcellulose is used in the comparative example instead of sodium pyrophosphate-modified cellulose ether.

[0035] Comparative Example 2

[0036] The method for preparing the sand-containing spray seal material in Comparative Example 2 is the same as that in Example 1, except for the components and their contents in the raw materials. Specifically, the reinforcing agent of this invention is not used in the comparative example, and its components are shown in Table 3 below.

[0037] Table 3. Raw material composition content of Comparative Example 2

[0038]

[0039] Example 2

[0040] The composition and content of the sand-containing fog seal material in Example 2 are shown in Table 4 below.

[0041] Table 4. Raw material composition content of Example 2

[0042]

[0043] The preparation process of the sand-containing fog sealing material in Example 2 is the same as that in Example 1.

[0044] Comparative Example 3

[0045] The method for preparing the sand-containing spray seal material in Comparative Example 3 is the same as that in Example 2, the difference being the components and their content in the raw materials. Specifically, hydroxypropyl methylcellulose is used instead of sodium pyrophosphate-modified cellulose ether in the comparative example.

[0046] Comparative Example 4

[0047] The method for preparing the sand-containing spray seal material in Comparative Example 4 is the same as that in Example 2, except for the components and their contents in the raw materials. Specifically, the reinforcing agent of this invention is not used in the comparative example, and its components are shown in Table 5 below.

[0048] Table 5. Raw material composition content of Comparative Example 4

[0049]

[0050] Example 3

[0051] The composition and content of the sand-containing fog seal material in Example 3 are shown in Table 6 below.

[0052] Table 6. Raw material composition content of Example 3

[0053]

[0054] The preparation process of the sand-containing fog sealing material in Example 3 is the same as that in Example 1.

[0055] Performance testing

[0056] The sand-containing fog seal material slurries prepared in Examples 1-3 and Comparative Examples 1-4 of this invention, after curing and forming a film, were subjected to performance testing in accordance with the "Technical Requirements for the Quality of Interlayer Bonding of Highway Asphalt Pavement" DB14 / T 647-2012. The results are shown in Table 7.

[0057] Table 7 Performance Comparison Table of Examples and Comparative Examples

[0058]

[0059] As shown in Table 7, the sand-containing fog sealing material prepared by the present invention using specific stabilizers and reinforcing agents has a surface drying time of no more than 30 minutes, a pull-out strength of over 0.9 MPa at 50°C, and a wet wheel abrasion value of no more than 26 g / m. 2 It exhibits good curing properties.

[0060] Based on the performance data of Example 1 and Comparative Example 1, and Example 2 and Comparative Example 3, the slurry obtained in Examples 1-3 all had a 24-hour bleeding rate of 0 at room temperature. However, Comparative Examples 1 and 3, which only added unmodified hydroxypropyl methylcellulose, had 2.4% and 2.1% bleeding rates at room temperature, respectively, after 24 hours. This indicates that the slurry with unmodified hydroxypropyl methylcellulose added to the sand-containing fog seal material had a higher bleeding rate, resulting in lower pull-out strengths at 25℃ and 50℃, and higher wet wheel abrasion (reflecting adhesion). Therefore, this invention uses sodium pyrophosphate-modified cellulose ether as a stabilizer. Compared to unmodified cellulose ether, the interfacial tension of the cellulose ether is significantly reduced after modification with sodium pyrophosphate, resulting in better dispersibility in water and less agglomeration. Figure 1 As shown, the cellulose ether modified with sodium pyrophosphate simultaneously enhances the cohesiveness between the components of the prepared sand-containing fog seal material system, avoiding stratification and segregation between the aggregate and the adhesive, and improving the overall dispersion performance of the material system, i.e., uniform dispersion of each component and no bleeding. Furthermore, the cellulose ether modified with sodium pyrophosphate enhances the adhesion between the sand fog seal material and the original pavement to be repaired.

[0061] Based on the above performance data analysis, the reason lies in the combination of oxygen atoms in sodium pyrophosphate and hydrogen atoms in cellulose ether to form multiple hydroxyl groups. This enhances the dispersibility of cellulose ether in the sand-containing fog seal slurry and improves the overall cohesiveness of the slurry. Simultaneously, the phosphate groups in the sodium pyrophosphate-modified cellulose ether promote complexation with metal ions in asphalt concrete aggregates, effectively agglomerating loose aggregates. The polar groups such as hydroxyl and ether bonds strengthen the adhesion between the cured sand-containing fog seal material and the asphalt-based pavement material. Therefore, using sodium pyrophosphate-modified cellulose ether as a stabilizer can reduce the bleeding rate of the sand-containing fog seal slurry, improve the stability of the sand-containing fog seal material, and enhance the adhesion of the material system, achieving higher adhesion to the pavement. Figure 2 As shown, the sand-containing fog seal material has cured into a film in good condition.

[0062] Furthermore, under the condition of stabilizer, when reinforcing agents are added to sand-containing fog seal materials, the phosphate groups in the stabilizer synergistically promote the adhesion of the alkoxy, hydroxyl, and carboxyl groups in the interface reinforcing agent to the original road surface and improve wear resistance.

[0063] It should be noted that the raw materials and their contents used in this invention can achieve the technical effects claimed above, therefore, no separate tests are needed to verify each one. For example, the aggregate can be selected from one or more of 20-80 mesh silica powder, limestone powder, and alumina powder. The dispersant can be selected from one or more of octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, and dodecylamine polyoxyethylene ether. The film-forming agent can be selected from one or more of dodecyl alcohol ester, hexadecyl alcohol ester, and propylene glycol phenyl ether. The mass ratio of water-based latex to emulsified asphalt can be (0.6-1):(1:0.6). The mass ratio of cellulose ether to sodium pyrophosphate can be 1:(1-2). The mass ratio of calcium hydroxide to ethanol can be 1:(1-2). The amount of tetrabutyl titanate added can be 0.1-0.3 times the mass of calcium hydroxide.

Claims

1. A sand-containing fog sealing material, characterized in that, The raw materials include the following parts by weight: 40-60 parts of adhesive, 30-50 parts of aggregate, and 5-10 parts of additives; The adhesive is a mixture of water-based latex and emulsified asphalt in a mass ratio of (0.6:1) to (1:0.6); The additives include 1-3 parts of sodium pyrophosphate modified cellulose ether stabilizer, 0.5-2 parts of dispersant, 2-5 parts of reinforcing agent, and 1.5-3 parts of film-forming agent.

2. The sand-containing fog sealing material according to claim 1, characterized in that, The stabilizer was prepared by adding sodium pyrophosphate to cellulose ether and stirring at a constant temperature of 40-60°C until a pale yellow liquid was formed; then the yellow liquid was washed until the pH value was 6-7 to obtain the stabilizer gel.

3. The sand-containing fog sealing material according to claim 2, characterized in that, The mass ratio of the cellulose ether to sodium pyrophosphate is 1:(1-2).

4. The sand-containing fog sealing material according to claim 1, characterized in that, The reinforcing agent is prepared by the following method: calcium hydroxide powder is ground and then added to ethanol and stirred evenly at room temperature; tetrabutyl titanate is added, and the mixture is stirred at 30-50℃ for 10-20 minutes and then dried.

5. The sand-containing fog sealing material according to claim 4, characterized in that, The mass ratio of calcium hydroxide to ethanol is 1:(1-2); the amount of tetrabutyl titanate added is 0.1-0.3 times the mass of calcium hydroxide.

6. The sand-containing fog sealing material according to claim 1, characterized in that, The water-based latex is selected from one or more of silicone-acrylic latex, chloroprene latex, and styrene-acrylic latex; the emulsified asphalt is selected from one or more of SBR-modified emulsified asphalt, SBS-modified emulsified asphalt, EVA-modified emulsified asphalt, and rubber powder-modified emulsified asphalt.

7. The sand-containing fog sealing material according to claim 1, characterized in that, The aggregate is selected from one or more of the following: 20-80 mesh silica powder, limestone powder, and alumina powder.

8. The sand-containing fog sealing material according to claim 1, characterized in that, The dispersant is selected from one or more of octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, and dodecylamine polyoxyethylene ether.

9. The sand-containing fog sealing material according to claim 1, characterized in that, The film-forming agent is selected from one or more of dodecyl alcohol ester, hexadecyl alcohol ester, and propylene glycol phenyl ether.

10. A method for preparing the sand-containing fog sealing material according to any one of claims 1-9, characterized in that, Includes the following steps: Add the additives to the adhesive solution and stir to form a uniform mixture; add the aggregate to the mixture and stir until uniform.

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