100% rap recycled cold patch material and method of making

Abstract

The application provides a 100% RAP regenerative cold patch material and a preparation method thereof, and belongs to the field of road engineering materials, wherein the 100% RAP regenerative cold patch material prepared by the application is prepared by compounding 0-3 mm, 3-5 mm and 5-10 mm three kinds of graded RAP materials in a specific proportion, so that 100% full-component efficient recycling of the waste and old asphalt pavement milling material is realized, and the waste and resource waste of the fine particle size RAP material are avoided. After curing, the material has excellent bonding performance and durability, and the dynamic stability of three parallel test pieces is 5673 times / mm, 6275 times / mm and 5744 times / mm respectively, the average value is 5897 times / mm, and the rut depth is less than 0.6 mm, which fully meets the high-temperature stability technical requirements of the modified asphalt mixture for the surface layer of the expressway. Through the Marshall stability and residual stability test, the Marshall stability of 5.32 kN is reached within 60 min, a technical breakthrough that the traffic can be opened after compaction is realized, and the performance level is significantly better than the performance level that the traditional cold patch material needs to be maintained for several days before being put into use.

Description

Technical Field

[0001] This invention relates to the field of road engineering materials technology, and in particular to a 100% RAP recycled cold patching material and its preparation method. Background Technology

[0002] As highway construction gradually shifts from the construction phase to the maintenance phase, a large amount of reclaimed asphalt pavement (RAP) is generated annually. Statistics show that a single region alone generates over 500,000 tons of RAP annually. The stockpiling of large quantities of RAP not only occupies land resources but also causes environmental pollution and resource waste. How to achieve efficient recycling of RAP has become a critical issue urgently needing to be addressed in the road maintenance field.

[0003] Currently, the recycling of RAP (Rich Asphalt Particulate) mainly includes two technical routes: hot recycling and cold recycling. Hot recycling technology requires heating the RAP to a high temperature (usually 140-150℃) before mixing it with virgin material. This process is energy-intensive, produces a large amount of carbon emissions, and the asphalt will further age during the heating process, reducing the performance of the recycled mixture. In addition, hot recycling technology is severely limited by weather and temperature conditions, making it difficult to carry out in winter and rainy or snowy weather.

[0004] Although cold patching technology has been applied to some extent in road maintenance, the existing cold patching materials have the following technical defects: low RAP utilization rate. In the existing cold patching technology, the RAP material content is usually only 30%-50%, and the 0-5mm RAP fine material is difficult to be effectively recycled due to its large specific surface area and high degree of aging. It is often discarded or downgraded, resulting in resource waste. Summary of the Invention

[0005] In view of this, it is necessary to provide a 100% RAP recycled cold patch material that can achieve 100% full-component utilization of waste asphalt pavement milling material, especially including 0-5mm fine particles, with excellent bonding and durability properties; It is also necessary to provide a method for preparing 100% RAP recycled cold patch material.

[0006] In a first aspect, the present invention provides a 100% RAP recycled cold patch material, comprising bio-based recycled cold patch material and epoxy resin, wherein the bio-based recycled cold patch material and the epoxy resin are packaged separately and mixed in a predetermined ratio when used. The bio-based recycled cold mix material comprises the following raw materials in parts by weight: 960-980 parts of waste asphalt pavement milling material and 20-40 parts of bio-based recycled cold mix liquid. The waste asphalt pavement milling material comprises RAP material with three gradations of 0-3mm, 3-5mm and 5-10mm mixed in a mass ratio of (190-198):(372-380):(396-404). The bio-based regenerated cold mix liquid comprises the following raw materials in parts by weight: 75-85 parts matrix bitumen, 5-15 parts waste vegetable oil, and 5-15 parts soybean oil.

[0007] Preferably, the base asphalt can be No. 70 road petroleum asphalt or No. 90 road petroleum asphalt, the waste vegetable oil has an acid value ≤5mgKOH / g and a moisture content ≤0.5%, and the soybean oil has an iodine value of 120-140.

[0008] Preferably, the bio-based regenerated cold mix liquid has a Bush rotational viscosity of less than 13.0 Pa·s, an adhesion grade of 5, and a flash point greater than 200°C at 20-30°C, and the epoxy resin has an epoxy equivalent of 184-194 g / eq and a rotational viscosity of 8-15 Pa·s at 25°C.

[0009] Preferably, the predetermined ratio is specifically a mass ratio of (9.5-10.5):(0.5-1.5).

[0010] On the other hand, the present invention provides a method for preparing 100% RAP recycled cold patching material, which specifically includes the following steps: Step 1: The waste asphalt pavement milling material is crushed, dried, dusted, and screened in sequence to obtain three grades of RAP material: 0-3mm, 3-5mm, and 5-10mm. 75-85 parts of base asphalt, 5-15 parts of waste vegetable oil, and 5-15 parts of soybean oil are mixed evenly at 20-30℃ to prepare bio-based recycled cold mix liquid. Step 2: Pour the RAP materials with three gradations of 0-3mm, 3-5mm and 5-10mm into a forced mixer at a mass ratio of (190-198):(372-380):(396-404) and mix them evenly to obtain a mixture. Step 3: At a predetermined temperature, add bio-based regenerated cold mix liquid to the mixture and stir in a forced mixer until no white material remains, to obtain bio-based regenerated cold mix material; Step 4: During construction, mix the bio-based recycled cold patch material with epoxy resin in a predetermined ratio to obtain 100% RAP recycled cold patch material.

[0011] Preferably, in step 1, the base asphalt can be No. 70 road petroleum asphalt or No. 90 road petroleum asphalt, the acid value of the waste vegetable oil is ≤5mgKOH / g, the moisture content is ≤0.5%, and the iodine value of the soybean oil is 120-140.

[0012] Preferably, the bio-based regenerated cold mix liquid has a Bush rotational viscosity of less than 13.0 Pa·s, an adhesion grade of 5, and a flash point greater than 200°C at 20-30°C, and the epoxy resin has an epoxy equivalent of 184-194 g / eq and a rotational viscosity of 8-15 Pa·s at 25°C.

[0013] Preferably, in step 3, the predetermined temperature is 20-30℃.

[0014] Preferably, in step 4, the predetermined ratio is specifically a mass ratio of (9.5-10.5):(0.5-1.5).

[0015] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention provides a 100% RAP recycled cold patch material, which achieves 100% efficient recycling of waste asphalt pavement milling material by using RAP materials with three gradations of 0-3mm, 3-5mm, and 5-10mm in a specific ratio, avoiding the waste and resource waste of fine-grained RAP materials. Furthermore, after curing, it exhibits excellent adhesion and durability. Rutting tests verified that the dynamic stability of the three parallel specimens were 5673 cycles / mm, 6275 cycles / mm, and 5744 cycles / mm, with an average of 5897 cycles / mm. The rutting depth was less than 0.6mm, fully meeting the high-temperature stability technical requirements for modified asphalt mixtures used in highway surface layers. According to Marshall stability and residual stability tests, the 100% RAP recycled cold patch material provided by this invention reaches a Marshall stability of 5.32kN within 60 minutes, achieving a technological breakthrough that allows traffic to be opened immediately after compaction. This is significantly better than the performance level of traditional cold patch materials that require several days of curing before they can be used. Attached Figure Description

[0016] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0017] Figure 1 This is a diagram showing the rutting test results of the first specimen.

[0018] Figure 2 This is a diagram showing the rutting test results of the second specimen.

[0019] Figure 3 This is a diagram showing the rutting test results of the third specimen.

[0020] Figure 4 Macroscopic photograph of 100% RAP recycled cold patch material after an adhesion grade test. Detailed Implementation

[0021] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0022] In a first aspect, the present invention provides a 100% RAP recycled cold patch material, comprising bio-based recycled cold patch material and epoxy resin, wherein the bio-based recycled cold patch material and the epoxy resin are packaged separately and mixed in a predetermined ratio when used. The bio-based recycled cold mix material comprises the following raw materials in parts by weight: 960-980 parts of waste asphalt pavement milling material and 20-40 parts of bio-based recycled cold mix liquid. The waste asphalt pavement milling material comprises RAP material with three gradations of 0-3mm, 3-5mm and 5-10mm mixed in a mass ratio of (190-198):(372-380):(396-404). The bio-based regenerated cold mix liquid comprises the following raw materials in parts by weight: 75-85 parts matrix bitumen, 5-15 parts waste vegetable oil, and 5-15 parts soybean oil.

[0023] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention provides a 100% RAP recycled cold patch material, which achieves 100% efficient recycling of waste asphalt pavement milling material by using RAP materials with three gradations of 0-3mm, 3-5mm, and 5-10mm in a specific ratio, avoiding the waste and resource waste of fine-grained RAP materials. Furthermore, after curing, it exhibits excellent adhesion and durability. Rutting tests verified that the dynamic stability of the three parallel specimens were 5673 cycles / mm, 6275 cycles / mm, and 5744 cycles / mm, with an average of 5897 cycles / mm. The rutting depth was less than 0.6mm, fully meeting the high-temperature stability technical requirements for modified asphalt mixtures used in highway surface layers. According to Marshall stability and residual stability tests, the 100% RAP recycled cold patch material provided by this invention reaches a Marshall stability of 5.32kN within 60 minutes, achieving a technological breakthrough that allows traffic to be opened immediately after compaction. This is significantly better than the performance level of traditional cold patch materials that require several days of curing before they can be used.

[0024] Furthermore, the base asphalt can be No. 70 or No. 90 road petroleum asphalt, the waste vegetable oil has an acid value ≤5mgKOH / g and a moisture content ≤0.5%, and the soybean oil has an iodine value of 120-140.

[0025] Furthermore, the bio-based regenerated cold mix liquid has a Bush rotational viscosity of less than 13.0 Pa·s, an adhesion grade of 5, and a flash point greater than 200℃ at 20-30℃, and the epoxy resin has an epoxy equivalent of 184-194 g / eq and a rotational viscosity of 8-15 Pa·s at 25℃.

[0026] Furthermore, the predetermined ratio is specifically a mass ratio of (9.5-10.5):(0.5-1.5).

[0027] On the other hand, the present invention provides a method for preparing 100% RAP recycled cold patching material, which specifically includes the following steps: Step 1: The waste asphalt pavement milling material is crushed, dried, dusted, and screened in sequence to obtain three grades of RAP material: 0-3mm, 3-5mm, and 5-10mm. 75-85 parts of base asphalt, 5-15 parts of waste vegetable oil, and 5-15 parts of soybean oil are mixed evenly at 20-30℃ to prepare bio-based recycled cold mix liquid. Step 2: Pour the RAP materials with three gradations of 0-3mm, 3-5mm and 5-10mm into a forced mixer at a mass ratio of (190-198):(372-380):(396-404) and mix them evenly to obtain a mixture. Step 3: At a predetermined temperature, add bio-based regenerated cold mix liquid to the mixture and stir in a forced mixer until no white material remains, to obtain bio-based regenerated cold mix material; Step 4: During construction, mix the bio-based recycled cold patch material with epoxy resin in a predetermined ratio to obtain 100% RAP recycled cold patch material.

[0028] Furthermore, in step 1, the base asphalt can be No. 70 road petroleum asphalt or No. 90 road petroleum asphalt, the acid value of the waste vegetable oil is ≤5mgKOH / g, the moisture content is ≤0.5%, and the iodine value of the soybean oil is 120-140.

[0029] Furthermore, the bio-based regenerated cold mix liquid has a Bush rotational viscosity of less than 13.0 Pa·s, an adhesion grade of 5, and a flash point greater than 200℃ at 20-30℃, and the epoxy resin has an epoxy equivalent of 184-194 g / eq and a rotational viscosity of 8-15 Pa·s at 25℃.

[0030] Furthermore, in step 3, the predetermined temperature is 20-30℃.

[0031] Furthermore, in step 4, the predetermined ratio is specifically a mass ratio of (9.5-10.5):(0.5-1.5).

[0032] To further understand the present invention, the following embodiments of the method of the present invention demonstrate 100% RAP recycled cold patching material and its preparation method. Unless otherwise specified, the methods described are conventional, and the raw materials, unless otherwise specified, can be obtained from publicly available commercial sources or their usage methods can be found in published literature.

[0033] Material source and pretreatment The waste asphalt pavement milling material (RAP) used in this invention is taken from waste asphalt pavement milling material in road maintenance projects. The above-mentioned RAP material is crushed, dried, and dusted in sequence, and then screened using a standard square hole sieve. RAP material that passes through a 3mm sieve, passes through a 5mm sieve but not through a 3mm sieve, and passes through a 10mm sieve but not through a 5mm sieve is collected respectively, thus obtaining RAP material with three gradations: 0-3mm, 3-5mm, and 5-10mm, for later use.

[0034] The bio-based recycled cold mix is ​​composed of the following raw materials by weight: 80 parts of base asphalt (No. 90 road petroleum asphalt), 10 parts of waste vegetable oil that has been pretreated by dehydration and deacidification, wherein the acid value of the waste vegetable oil is ≤5mgKOH / g and the moisture content is ≤0.5%, and 10 parts of industrial grade soybean oil (iodine value 120-140).

[0035] Preparation method: Under conditions of 20-30℃, add the above-mentioned base asphalt, waste vegetable oil, and soybean oil to a mixing container in proportion, and stir at a speed of 300-500 r / min for 15-30 minutes until the mixture becomes a uniform viscous liquid, which is the bio-based recycled cold mix solution. The technical indicators of this bio-based recycled cold mix solution are shown in Table 1.

[0036] Table 1. Technical Specifications of Bio-based Regenerated Cold Mixing Liquid Purchase bisphenol A type liquid epoxy resin with an epoxy equivalent of 184-194 g / eq, a rotational viscosity of 8-15 Pa·s at 25℃, and a solid content of ≥99.0%, packaged in 500g containers for later use.

[0037] Bio-based Regenerated Cold Compensation Preparation Process Weigh the raw materials according to the following parts by weight: 0-3mm RAP material: 194 parts; 3-5mm RAP material: 376 parts; 5-10mm RAP material: 400 parts; bio-based regenerated cold mix liquid: 30 parts.

[0038] Add the 194 parts of 0-3mm RAP material, 376 parts of 3-5mm RAP material, and 400 parts of 5-10mm RAP material to the forced mixer in sequence, ensuring that the total amount of material does not exceed 85% of the maximum capacity of the forced mixer. Start the forced mixer and dry mix for 30-60 seconds to ensure that each RAP material is fully and evenly mixed.

[0039] Maintain the ambient temperature between 20-30℃ (if the ambient temperature is below 20℃, preheat component A in a 40-50℃ water bath for 30 minutes until it reaches a fluid state). Add 30 parts of bio-based regenerated cold mix liquid to the forced mixer and continue mixing for 3-5 minutes. Stop the machine and check the state of the mixture. The mixture should be uniform, free of white spots, with the oil evenly coated on the surface of the RAP material, and full and not dry. If white spots appear, continue mixing for 1-2 minutes until the above requirements are met to obtain the bio-based regenerated cold mix material.

[0040] The bio-based recycled cold patch material is packaged in 25kg bags and sealed for storage. It can be stored for 1 year at room temperature.

[0041] On-site construction During construction, take 25kg of bio-based recycled cold patch material and 2.5kg of epoxy resin, and mix them on the construction site using a small forced mixer or manual mixing. The mixing time is 2-3 minutes until the mixture is uniform in color, thus obtaining 100% RAP recycled cold patch material.

[0042] Fill the cleaned potholes with the mixed 100% RAP recycled cold patch material, spread and level it, and then compact it using a small roller or vibratory tamper, passing it 3-4 times. Traffic can be opened after compaction.

[0043] Performance testing 1. The 100% RAP recycled cold patch material prepared by the method of this invention shall be subjected to rutting tests in accordance with the provisions of T0719 in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20). The specific test steps are as follows: The test temperature was 60℃, the wheel pressure was 0.7MPa, and the specimen size was 300mm×300mm×50mm. Three sets of parallel specimens were designated as the first, second, and third specimens. Figure 1 The rutting test results of the first specimen, Figure 2 The rutting test results of the second specimen, Figure 3 For the rutting test results of the third specimen, please refer to [link / reference]. Figures 1 to 3The test results show that the average dynamic stability of the 100% RAP recycled cold patch material of this invention is 5897 cycles / mm, and the rutting depth is less than 0.6mm, which fully meets the technical requirement of ≥2800 cycles / mm for the dynamic stability of modified asphalt mixtures for the surface layer of expressways and first-class highways in the "Technical Specification for Construction of Highway Asphalt Pavement" (JTG F40).

[0044] 2. The 100% RAP recycled cold patch material prepared by the method of this invention shall be subjected to Marshall stability and residual stability tests in accordance with the provisions of Clause 5.3.2 of "Cold Patch Material for Potholes in Asphalt Pavement" (JT / T 972-2015). The specific test steps are as follows: Approximately 1100g of 100% RAP recycled cold patch material was weighed and placed into a Marshall mold at room temperature. The mold was compacted 25 times on both sides, resulting in two sets of samples. The samples, along with their molds, were placed upright on their sides in a 110℃ oven for 24 hours. After removal, they were compacted 25 times on both sides again, ensuring the sample height was controlled at 63.5mm ± 1.3mm. One set of samples was demolded and cured in a 25℃ constant temperature water bath for 60 minutes before undergoing a Marshall test to measure its stability (MS). The other set of samples was demolded and cured in a 25℃ constant temperature water bath for 48 hours before undergoing a Marshall test to measure its stability (MS1). Residual stability was calculated as (MS1 / MS) × 100%. The test results are shown in Table 2.

[0045] Table 2. Results of Marshall stability and residual stability tests The test results show that the 100% RAP recycled cold patch material prepared by the method of the present invention has a Marshall stability of 5.32 kN at 60 min, a Marshall stability of 4.59 kN at 48 h, and a residual stability of 86.3%. All of the above indicators meet the technical requirements of stability ≥3.0 kN and residual stability ≥85% in "Cold Patch Material for Potholes in Asphalt Pavement" (JT / T 972-2015).

[0046] 3. An adhesion grade test (JT / T972-2015) was conducted on the 100% RAP recycled cold patching material prepared by the method of this invention. The specific test steps are as follows: Pour approximately 800 mL of distilled water into a clean 1000 mL beaker and heat to boiling. Weigh 250 g of 100% RAP recycled cold patch mix and add it to the boiling water. Stir continuously with a glass rod at a rate of one revolution per second for 3 minutes. Stop heating, skim off any floating bitum, and allow to cool to room temperature. Discard the water and place the wet mix on a piece of white paper. Figure 4 As shown in the macroscopic photograph. The adhesion grade was visually assessed according to Table T0616-1 of JTG E20-2011.

[0047] Observed Figure 4 It can be seen that the asphalt film of the 100% RAP recycled cold patch material of the present invention is intact and without peeling, and the adhesion grade is rated as level 5, which meets the technical requirement of adhesion grade ≥ 4 in JT / T 972-2015.

[0048] Therefore, this invention achieves 100% full-component recycling of waste asphalt pavement milling material by using three gradations of RAP material: 0-3mm, 3-5mm, and 5-10mm. Furthermore, by combining base asphalt, waste vegetable oil, and soybean oil in the bio-based recycled cold mix, this invention controls the Bush rotation viscosity at room temperature (20-30℃) below 13.0 Pa·s, achieving uniform mixing and good adhesion of 100% RAP recycled cold patch material. Finally, through the independent packaging and on-site cross-linking and curing of bio-based recycled cold patch material and epoxy resin, the 100% RAP recycled cold patch material can reach a Marshall stability of 5.32 kN within 60 minutes after compaction, achieving a technological breakthrough of opening the road to traffic immediately after compaction. This is significantly better than the performance level of traditional cold patch materials that require several days of curing before they can be used.

[0049] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that all or part of the processes for implementing the above embodiments, and equivalent variations made in accordance with the claims of the present invention, are still covered by the invention.

Claims

1. A 100% RAP cold patching material, characterized in that, It includes bio-based recycled cold patch material and epoxy resin, wherein the bio-based recycled cold patch material and the epoxy resin are packaged separately and mixed in a predetermined ratio before use; The bio-based recycled cold mix material comprises the following raw materials in parts by weight: 960-980 parts of waste asphalt pavement milling material and 20-40 parts of bio-based recycled cold mix liquid. The waste asphalt pavement milling material comprises RAP material with three gradations of 0-3mm, 3-5mm and 5-10mm mixed in a mass ratio of (190-198):(372-380):(396-404). The bio-based regenerated cold mix liquid comprises the following raw materials in parts by weight: 75-85 parts matrix bitumen, 5-15 parts waste vegetable oil, and 5-15 parts soybean oil.

2. The 100% RAP cold patch recycling material of claim 1, wherein, The base asphalt can be No. 70 or No. 90 road petroleum asphalt, the waste vegetable oil has an acid value ≤5mgKOH / g and a moisture content ≤0.5%, and the soybean oil has an iodine value of 120-140.

3. The 100% RAP cold patch recycling material of claim 1, wherein, The bio-based regenerated cold mix liquid has a Bush rotational viscosity of less than 13.0 Pa·s, an adhesion grade of 5, and a flash point greater than 200℃ at 20-30℃. The epoxy resin has an epoxy equivalent of 184-194 g / eq and a rotational viscosity of 8-15 Pa·s at 25℃.

4. The 100% RAP cold patch recycling material of claim 1, wherein, The predetermined ratio is specifically a mass ratio of (9.5-10.5):(0.5-1.5).

5. A process for the preparation of 100% RAP cold patching material, characterized by, Specifically, the following steps are included: Step 1: The waste asphalt pavement milling material is crushed, dried, dusted, and screened in sequence to obtain three grades of RAP material: 0-3mm, 3-5mm, and 5-10mm. 75-85 parts of base asphalt, 5-15 parts of waste vegetable oil, and 5-15 parts of soybean oil are mixed evenly at 20-30℃ to prepare bio-based recycled cold mix liquid. Step 2: Pour the RAP materials with three gradations of 0-3mm, 3-5mm and 5-10mm into a forced mixer at a mass ratio of (190-198):(372-380):(396-404) and mix them evenly to obtain a mixture. Step 3: At a predetermined temperature, add bio-based regenerated cold mix liquid to the mixture and stir in a forced mixer until no white material remains, to obtain bio-based regenerated cold mix material; Step 4: During construction, mix the bio-based recycled cold patch material with epoxy resin in a predetermined ratio to obtain 100% RAP recycled cold patch material.

6. The 100% RAP cold-recycled mix according to claim 5, characterized in that, In step 1, the base asphalt can be No. 70 road petroleum asphalt or No. 90 road petroleum asphalt, the acid value of the waste vegetable oil is ≤5mgKOH / g, the moisture content is ≤0.5%, and the iodine value of the soybean oil is 120-140.

7. The 100% RAP cold-recycled mix according to claim 5, characterized in that, The bio-based regenerated cold mix liquid has a Bush rotational viscosity of less than 13.0 Pa·s, an adhesion grade of 5, and a flash point greater than 200℃ at 20-30℃. The epoxy resin has an epoxy equivalent of 184-194 g / eq and a rotational viscosity of 8-15 Pa·s at 25℃.

8. The 100% RAP recycled cold patching material as described in claim 5, characterized in that, In step 3, the predetermined temperature is 20-30℃.

9. The 100% RAP recycled cold patching material as described in claim 5, characterized in that, In step 4, the predetermined ratio is specifically a mass ratio of (9.5-10.5):(0.5-1.5).

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