Water reaction type cold-mix asphalt mixture and preparation method thereof

Abstract

The invention discloses a water reaction type cold-mix asphalt mixture which is prepared from the following raw materials in parts by weight: 1-1.5 parts of dimethylformamide, 0.5-1 part of tung oil, 4-5 parts of matrix asphalt, 0.05-0.1 part of a curing agent and 100 parts of aggregate, 1-2 parts of reaction medium water is added during use; the preparation method comprises the following steps: 1, heating the matrix asphalt to 140-150 DEG C for later use; 2, adding dimethylformamide, tung oil and a curing agent into the matrix asphalt to be used, and uniformly stirring to prepare cold-mixed asphalt; and 3, mixing the cold-mixed asphalt with the aggregate to prepare the cold-mixed asphalt mixture. The dimethylformamide, the tung oil and the curing agent are added into the water reaction type cold-mixed asphalt mixture, and water is used as an activating agent, so that the cold-mixed asphalt mixture rapidly forms strength, and the mixture is rapid in hardening, early in strength, high in compactness, good in water resistance, few in component, green, environmentally friendly and suitable for pavement maintenance overlay and pit slot repair.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt mixture preparation, and in particular relates to a water-reactive cold-mix asphalt mixture and a preparation method thereof. Background Art

[0002] Potholes are typical diseases of asphalt pavement, which will seriously affect the flatness and driving comfort of the road surface. If they are not repaired in time, under the combined effects of heavy-loaded vehicles and rain, potholes will develop rapidly, which will not only increase maintenance costs, but also seriously endanger the safety of drivers and passengers. Due to its great safety hazards, it is usually required in daily highway maintenance management that "potholes should not be left overnight", that is, potholes should be repaired in time when they appear. Currently, the commonly used pothole repair technologies can be divided into two categories: hot patching and cold patching. The advantages of the hot patching method are good repair quality and strong durability, but the construction process is more complicated, special equipment for heating and mixing is required, the construction efficiency is low, and it is greatly affected by the temperature; the advantage of the cold patching method is that no special equipment is required, and it can still be constructed in high-altitude cold areas or in winter when the temperature is low, but traditional cold patch materials are mostly solvent-diluted materials, which have slow strength formation and are easy to disperse when exposed to water, poor repair quality, and short service life. They are generally only used for emergency maintenance. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a water-reactive cold-mix asphalt mixture in view of the above-mentioned deficiencies of the prior art. The water-reactive cold-mix asphalt mixture is added with dimethylformamide, tung oil and calcium hydroxide, and water is used as an activator, so that the cold-mix asphalt mixture can quickly form strength, have good repair quality, long service life, and shorten the repair time, thereby solving the disadvantage of the traditional cold-mix asphalt mixture being afraid of water erosion.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a water-reactive cold-mix asphalt mixture, characterized in that it is made of the following raw materials in parts by weight: 1 to 1.5 parts of dimethylformamide, 0.5 to 1 part of tung oil, 4 to 5 parts of base asphalt, 0.05 to 0.1 part of curing agent, and 100 parts of aggregate; by weight, 1 to 2 parts of reaction medium water are added to the cold-mix asphalt mixture when it is used.

[0005] In order to solve the problem that traditional cold patch materials are afraid of water and give full play to the process advantages of cold patch materials, the present invention has developed a water-reactive cold-mix asphalt mixture composed of base asphalt, asphalt diluent dimethylformamide and tung oil, water-reactive curing agent, aggregate and other materials. The present invention adds dimethylformamide and tung oil, and rapidly reacts with the curing agent, preferably calcium hydroxide, in the reaction medium water, so that the cold-mix asphalt mixture quickly forms strength, wherein the carbonyl group (C=O) in dimethylformamide has a certain electrophilicity, and reacts with the hydroxide ion (OH-) in the calcium hydroxide aqueous solution to form a nucleophilic addition reaction, and finally generates calcium formate, which is used as a concrete early strength agent to promote the rapid strength formation of the cold-mix asphalt mixture; and the tung oil is mixed with the calcium hydroxide aqueous solution to form a tung oil-lime mortar, which can accelerate the early structure formation of the cold-mix asphalt mixture. Therefore, the present invention adopts water as a medium to promote the chemical reaction between dimethylformamide and tung oil and the curing agent, that is, water can activate the chemical reaction between dimethylformamide and tung oil and the curing agent. Therefore, water must be introduced into the water-reactive cold-mix asphalt mixture of the present invention during the strength formation process, which solves the disadvantage of the traditional cold-mix asphalt mixture being afraid of water erosion.

[0006] The above-mentioned water-reactive cold-mix asphalt mixture is characterized in that it is made of the following raw materials in parts by weight: 1 part of dimethylformamide, 0.5 part of tung oil, 4 parts of base asphalt, 0.05 part of curing agent, and 100 parts of aggregate; by weight, 1 part of reaction medium water is added to the cold-mix asphalt mixture when it is used.

[0007] The above-mentioned water-reactive cold-mix asphalt mixture is characterized in that it is made of the following raw materials in parts by weight: 1.5 parts of dimethylformamide, 1 part of tung oil, 5 parts of base asphalt, 0.1 part of curing agent, and 100 parts of aggregate; by weight, 2 parts of reaction medium water are added to the cold-mix asphalt mixture when it is used.

[0008] The above-mentioned water-reactive cold-mix asphalt mixture is characterized in that the base asphalt is 90# road petroleum asphalt that meets the requirements of "Technical Specifications for Highway Asphalt Pavement Construction" (JTG F40-2004).

[0009] The above-mentioned water-reactive cold-mix asphalt mixture is characterized in that the curing agent is calcium hydroxide. This type of curing agent can not only promote the rapid formation of strength of the cold-mix asphalt mixture, but also has low cost and wide application, which is conducive to the large-scale production and promotion of the cold-mix asphalt mixture of the present invention.

[0010] The above-mentioned water-reactive cold-mix asphalt mixture is characterized in that the aggregate includes coarse aggregate of 5mm to 10mm, fine aggregate of 0 to 5mm, and mineral powder, and the mass ratio of coarse aggregate: fine aggregate: mineral powder = 60:38:2.

[0011] At the same time, the present invention also discloses a method for preparing the water-reactive cold mix asphalt mixture as described above, characterized in that the method comprises the following steps:

[0012] Step 1: Heat the base asphalt to 140°C to 150°C for standby use;

[0013] Step 2: Add dimethylformamide, tung oil and curing agent to the base asphalt to be used in step 1 and stir evenly to prepare cold mix asphalt;

[0014] Step 3: Mix the cold mix asphalt prepared in step 2 with the aggregate to prepare a cold mix asphalt mixture.

[0015] The present invention ensures that the cold-mix asphalt mixture has good fluidity at room temperature by controlling the order and method of adding various raw materials, thereby realizing the cold-mix preparation of the asphalt mixture.

[0016] The above-mentioned preparation method is characterized in that the cold-mix asphalt mixture prepared in step 3 is loaded into a test mold, and water is sprayed on the surface, and then compacted or rolled to obtain a cold-mix asphalt mixture specimen for mechanical property testing; based on the weight of the cold-mix asphalt mixture, the weight of the water added is 1 to 2 parts. This amount of water added ensures that the dimethylformamide, tung oil and curing agent in the cold-mix asphalt mixture are fully reacted.

[0017] The above-mentioned preparation method is characterized in that the mechanical property test includes Marshall stability, water-immersed Marshall residual stability, freeze-thaw splitting strength ratio, and 60°C rutting test. The performance of traditional cold-mix asphalt mixtures is far from reaching the technical level of hot-mix asphalt mixtures, so its evaluation indicators are also very simple, including only Marshall stability and water-immersed Marshall residual stability, and the test temperature is 25°C, not 60°C for hot-mix asphalt mixtures; for the developed water-reactive cold-mix asphalt mixture, the test indicators and test temperatures used in the present invention are completely based on the evaluation indicators of hot-mix asphalt mixtures, so as to make a horizontal comparison with hot-mix asphalt mixtures.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. The water-reactive cold-mix asphalt mixture of the present invention adds dimethylformamide, tung oil and a curing agent, and uses water as an activator to promote the chemical gel curing reaction, so that the cold-mix asphalt mixture can quickly form strength, have good repair quality and long service life, thereby solving the disadvantage of the traditional cold-mix asphalt mixture being afraid of water erosion.

[0020] 2. By adding dimethylformamide and tung oil to the water-reactive cold-mix asphalt mixture of the present invention, the asphalt still has good fluidity at room temperature after dilution, has high looseness and good fluidity in a water-free state, has excellent construction and workability, can coexist with the water-reactive curing agent for a long time when sealed and stored, and has good stability. When used, after the pavement is paved, the surface is sprinkled with water to moisten it and rolled in time, so that the curing agent can be activated to quickly undergo a water-activated reaction inside the mixture to form strength. The initial strength can be quickly formed in about 30 minutes, reaching the initial hardening state of the surface, the strength can be basically formed in 2 hours, and the Marshall stability can reach more than 6kN in 24 hours. In addition, various technical indicators can basically reach the technical level of hot-mix asphalt mixtures. Compared with the traditional solvent-based cold-mix asphalt mixture, which relies on the slow evaporation of the solvent to form early strength after a preparation cycle of more than one week, the time for repairing the road surface is greatly shortened.

[0021] 3. Compared with solvent-based cold-mix asphalt mixture, in order to ensure the workability of the mixture and reserve gaps for the later volatilization of solvents, its mineral material grading is mainly single-size aggregate, and the amount of machine-made sand and mineral powder is very small or even not used, resulting in a large porosity of the pavement after construction and forming, and it is difficult to ensure the density. Rainwater can easily seep in, making the cold-mix asphalt mixture, which has poor water stability, even worse in its ability to resist water damage and insufficient durability. At the same time, the water-reactive cold-mix asphalt mixture of the present invention has excellent workability itself and has good fluidity without heating. Therefore, even if AC-type dense grading is adopted, it can ensure that the mixture has good construction workability. From the grading point of view, it is ensured that the pavement after construction and forming can achieve a higher density, waterproof and anti-seepage, and achieve the durability goal.

[0022] 4. Compared with the traditional cold-mix asphalt mixture, which has poor performance and low early strength, it is usually used only as a temporary repair material or only used for the road base or lower layer for short-term repair in the current asphalt pavement maintenance field. The water-reactive cold-mix asphalt mixture of the present invention has rapid setting and early strength, high density, good water resistance, and fewer components. It is green and environmentally friendly and can completely replace hot-mix asphalt mixture for road maintenance overlay, pothole repair, etc.

[0023] The technical solution of the present invention is further described in detail below through embodiments. DETAILED DESCRIPTION

[0024] Example 1

[0025] The water-reactive cold-mix asphalt mixture of this embodiment is made of the following raw materials in parts by weight: 1 part of dimethylformamide, 0.5 part of tung oil, 4 parts of base asphalt, 0.05 part of curing agent calcium hydroxide, and 100 parts of aggregate; by weight, 1 part of reaction medium water is added to the cold-mix asphalt mixture when it is used; the base asphalt is 90# road petroleum asphalt that meets the requirements of "Technical Specifications for Highway Asphalt Pavement Construction" (JTG F40-2004); the aggregate includes coarse aggregate of 5mm to 10mm, fine aggregate of 0 to 5mm, and mineral powder, and the mass ratio is coarse aggregate: fine aggregate: mineral powder = 60:38:2.

[0026] The method for preparing the water-reactive cold mix asphalt mixture of the present embodiment comprises the following steps:

[0027] Step 1: Heat the base asphalt to 140°C to 150°C for standby use;

[0028] Step 2: Add dimethylformamide, tung oil and curing agent to the base asphalt to be used in step 1 and stir evenly to prepare cold mix asphalt;

[0029] Step 3: Mix the cold mix asphalt prepared in step 2 with the aggregate to prepare a cold mix asphalt mixture.

[0030] Example 2

[0031] The difference between this embodiment and embodiment 1 is: 1.5 parts of dimethylformamide, 1 part of tung oil, 5 parts of base asphalt, 0.1 part of curing agent calcium hydroxide, 100 parts of aggregate; by weight, 2 parts of reaction medium water are added to the cold mix asphalt mixture when it is used.

[0032] Example 3

[0033] The difference between this embodiment and embodiment 1 is: 10 parts of dimethylformamide, 1 part of tung oil, 5 parts of base asphalt, 0.1 part of curing agent calcium hydroxide, 100 parts of aggregate; by weight, 1 part of reaction medium water is added to the cold mix asphalt mixture when it is used.

[0034] Example 4

[0035] The difference between this embodiment and embodiment 1 is: 1.5 parts of dimethylformamide, 0.5 parts of tung oil, 4.5 parts of base asphalt, 0.05 parts of curing agent calcium hydroxide, 100 parts of aggregate; by weight, 1 part of reaction medium water is added to the cold mix asphalt mixture when it is used.

[0036] Example 5

[0037] The difference between this embodiment and embodiment 1 is: 1 part of dimethylformamide, 0.5 part of tung oil, 5 parts of base asphalt, 0.1 part of curing agent calcium hydroxide, 100 parts of aggregate; by weight, 2 parts of reaction medium water are added to the cold mix asphalt mixture when it is used.

[0038] The mineral aggregate gradation composition of the water-reactive cold mix asphalt mixture in Examples 1 to 5 of the present invention is shown in Table 1 below.

[0039] Table 1 Mineral aggregate gradation composition of asphalt mixture

[0040]

[0041] The water-reactive cold-mix asphalt mixtures prepared in Examples 1 to 5 of the present invention were respectively loaded into test molds, and water was sprayed on the surface. The weight of the water added was 1 to 2 parts based on the weight of the cold-mix asphalt mixture. Then, the cold-mix asphalt mixture specimens were compacted or rolled to obtain the cold-mix asphalt mixture specimens. The mechanical properties were tested according to the relevant test provisions of the standard JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures for Highway Engineering" issued by the Ministry of Transport, including Marshall stability, immersion Marshall residual stability, freeze-thaw splitting strength ratio, and 60°C rutting test, i.e., 60°C dynamic stability test. The results are shown in Table 2 below.

[0042] Table 2 Comparative test results of water-reactive cold mix asphalt mixture performance

[0043]

[0044] As can be seen from Table 2, the performance of the water-reactive cold-mix asphalt mixture of the present invention can reach the technical level of hot-mix asphalt mixture under the condition of cold mixing at room temperature, and can be widely used in the maintenance and repair of asphalt pavements in various climatic regions.

[0045] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A water-reactive cold mix asphalt mixture, characterized in that: The cold-mix asphalt mixture is prepared from the following raw materials in parts by weight: 1-1.5 parts of dimethylformamide, 0.5-1 parts of tung oil, 4-5 parts of base asphalt, 0.05-0.1 parts of curing agent, and 100 parts of aggregate. By weight, 1-2 parts of reaction medium water are added to the cold-mix asphalt mixture when it is used.

2. A water-reactive cold mix asphalt mixture according to claim 1, characterized in that: The cold-mix asphalt mixture is prepared from the following raw materials in parts by weight: 1 part of dimethylformamide, 0.5 parts of tung oil, 4 parts of base asphalt, 0.05 parts of curing agent, and 100 parts of aggregate; by weight, 1 part of reaction medium water is added to the cold-mix asphalt mixture when it is used.

3. The water-reactive cold mix asphalt mixture according to claim 1, characterized in that: The cold-mix asphalt mixture is prepared from the following raw materials in parts by weight: 1.5 parts of dimethylformamide, 1 part of tung oil, 5 parts of base asphalt, 0.1 part of curing agent, and 100 parts of aggregate; by weight, 2 parts of reaction medium water are added to the cold-mix asphalt mixture when it is used.

4. The water-reactive cold mix asphalt mixture according to claim 1, characterized in that: The base asphalt is 90# road petroleum asphalt that meets the requirements of "Technical Specifications for Highway Asphalt Pavement Construction" (JTG F40-2004).

5. The water-reactive cold mix asphalt mixture according to claim 1, characterized in that: The curing agent is calcium hydroxide.

6. The water-reactive cold mix asphalt mixture according to claim 1, characterized in that: The aggregate comprises coarse aggregate of 5 mm to 10 mm, fine aggregate of 0 mm to 5 mm, and mineral powder, and the mass ratio of coarse aggregate: fine aggregate: mineral powder is 60:38:

2.

7. A method for preparing a water-reactive cold mix asphalt mixture according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: Step 1: Heat the base asphalt to 140°C to 150°C for standby use; Step 2: Add dimethylformamide, tung oil and curing agent to the base asphalt to be used in step 1 and stir evenly to prepare cold mix asphalt; Step 3: Mix the cold mix asphalt prepared in step 2 with the aggregate to prepare a cold mix asphalt mixture.

8. The preparation method according to claim 7, characterized in that: The cold-mix asphalt mixture prepared in step 3 is placed in a test mold, and water is sprayed on the surface, and then compacted or rolled to obtain a cold-mix asphalt mixture specimen for mechanical property testing; based on the weight of the cold-mix asphalt mixture, the added weight of water is 1 to 2 parts.

9. The preparation method according to claim 8, characterized in that: The mechanical property tests include Marshall stability, water-immersion Marshall residual stability, freeze-thaw splitting strength ratio, and 60°C rutting test.

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