A cast asphalt mixture and a method of preparing and using the same

Abstract

The application provides a novel casting asphalt mixture (Ultra-high Performance Casting Asphalt, UHCA) and a preparation method and application thereof. The novel casting asphalt mixture is mainly prepared from the following raw materials in parts by weight: coarse aggregate 90-110 parts, asphalt 10-25 parts, and mineral powder 10-25 parts; wherein the particle size of the coarse aggregate is 4.75-13.2 mm, the dynamic viscosity of the asphalt at 60 DEG C is greater than 400000 Pa*s, and the particle size of the mineral powder is less than 0.075 mm. The novel casting asphalt mixture has a rut dynamic stability of more than 3000 times / mm, a low-temperature damage strain of more than 4000 με at-10 DEG C, and a smaller void ratio than traditional pavement structure materials, and has excellent high-temperature stability, low-temperature deformation capacity and durability, and meets the requirements of the specification on the performance of pavement materials, and can be used for pavement disease treatment and pavement structure layer paving, and has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of road traffic, in particular to a novel paving type asphalt mixture and a preparation method and application thereof. BACKGROUND

[0002] With the high-quality development of China's economy, the demand for transportation in various industries is increasing, which leads to the traffic volume of some old roads seriously exceeding the design value at that time. Long-term overload road conditions result in frequent road disease phenomena such as potholes, subsidence and cracks. Some conventional repair methods require a closed construction and a rolling process to ensure the quality of the mixture, which has a long construction period and seriously affects the traffic of vehicles. How to reduce the impact of maintenance construction on traffic is a difficult problem that needs to be solved in the field of road today.

[0003] The construction process of the paving type asphalt mixture can greatly shorten the treatment period of the disease, and does not need to be rolled after paving, which can handle some environments where large rolling equipment cannot be used. Although the traditional paving type asphalt mixture is widely used in steel bridge deck paving, it has not been popularized in road structure layers. The reason may be that the paving process requires a large oil-stone ratio, so that the mortar can self-flow at high temperature, which inevitably leads to poor high-temperature stability of the mixture. In addition, the paving type asphalt mixture must be mixed with hard Trinidad Lake asphalt to improve the high-temperature stability, and the dynamic stability of the rut is only 300-800 times / mm, which cannot meet the performance requirements of highway pavement structure materials. The above problems have not been solved for a long time.

[0004] In view of this, the present application is proposed. SUMMARY

[0005] The present application aims to provide a novel paving type asphalt mixture and a preparation method and application thereof, which has excellent high-temperature stability, low-temperature deformation ability and durability.

[0006] The present application provides a novel paving type asphalt mixture, which is mainly made of the following raw materials by weight: coarse aggregate 90-110 parts, asphalt 10-25 parts, and mineral powder 10-25 parts; wherein the particle size of the coarse aggregate is 4.75-13.2 mm; the dynamic viscosity of the asphalt at 60℃ is greater than 400000 Pa·s, preferably greater than 580000 Pa·s; and the particle size of the mineral powder is less than 0.075 mm.

[0007] Preferably, the novel paving type asphalt mixture is mainly made of the following raw materials by weight: coarse aggregate 100 parts, asphalt 13-15 parts, and mineral powder 15-23 parts.

[0008] In the present invention, the technical parameters of asphalt can be: the dynamic viscosity of asphalt at 60°C is greater than 400,000 Pa·s, preferably greater than 580,000 Pa·s, for example, it can be 600,000 Pa·s; the softening point is ≥ 60°C, preferably ≥ 90°C; the elongation (5°C, 5cm / min) is ≥ 20mm, preferably ≥ 30mm; the needle penetration (25°C, 100g, 5s) is in the range of 3.0-6.0 mm, preferably 4.8-5.2 mm.

[0009] In the present invention, the coarse aggregate comprises, by weight, 60-70 parts of a first coarse aggregate of 4.75-9.5 mm and 30-40 parts of a second coarse aggregate of 9.5-13.2 mm. Preferably, the coarse aggregate comprises, by weight, 62-64 parts of the first coarse aggregate of 4.75-9.5 mm and 36-38 parts of the second coarse aggregate of 9.5-13.2 mm. The coarse aggregate may be diabase coarse aggregate.

[0010] In the present invention, the mineral powder is limestone mineral powder; the technical parameters of the mineral powder are as follows: apparent relative density ≥ 2.80g / cm 3 ;Specific surface area ≥400m 2 / kg; water content ≤1.0%.

[0011] The present invention also provides a method for preparing the novel pourable asphalt mixture, comprising the following steps in sequence:

[0012] S1: Determine the mixing temperature T of the mixture based on the viscosity-temperature curve of asphalt M ℃;

[0013] S2: Two-stage heating of asphalt, coarse aggregate and mineral powder respectively;

[0014] S3: placing the heated coarse aggregate in a mixer according to weight for the first mixing, then adding asphalt for the second mixing, and then adding mineral powder for the third mixing;

[0015] S4: The mixed mixture is placed into a formwork, and then placed in a vibrator for vibration to obtain a new type of pouring asphalt mixture.

[0016] In the present invention, in step S1, the viscosity-temperature curve of asphalt can be determined according to the asphalt rotation viscosity test, and then the mixing temperature T of the mixture can be determined according to the viscosity-temperature curve of asphalt. M ℃; specifically, mixing temperature T M ℃ is 190-210 ℃, for example 200 ℃.

[0017] In step S2, the first stage heating temperature is controlled to be higher than the mixing temperature T M ℃ lower by 15-25 ℃, for example, T M℃-20℃; the first heating time is 2-3 h; the second heating temperature is the mixing temperature T M ℃, the second heating time is 40-80 min, for example, 1 h.

[0018] In step S3, the temperature of each mixing is controlled to be 15-25 ℃ higher than the mixing temperature T M M ℃+20℃; the time of each mixing is controlled to be 80-100 s.

[0019] In step S4, the vibration time is controlled to be 90-120 s; the void ratio of the new paving asphalt mixture is less than 1%.

[0020] The application also provides the application of the new paving asphalt mixture or the new paving asphalt mixture prepared according to the above preparation method in road disease treatment or road structure layer paving.

[0021] The implementation of the application has at least the following advantages:

[0022] 1. The new paving asphalt mixture of the application is different from the traditional mixture design, which uses coarse aggregate to ensure the skeleton system of the mixture, uses mineral powder and asphalt to reasonably fill the structural space of the mixture, and does not need fine aggregate, so that the mixture reaches the self-compacting state through the high flowability of the mortar in the high-temperature state, and the traditional suspension compacting structure is abandoned, and the void ratio is less than 1%.

[0023] 2. The rutting dynamic stability of the new paving asphalt mixture of the application reaches more than 3000 times / mm, which is excellent compared with the ordinary paving asphalt mixture; and the low-temperature failure strain can reach more than 4000 με at-10 ℃, which has excellent low-temperature deformation capacity on the premise of ensuring high-temperature stability, meets the requirements of the specification on the performance of road materials, overcomes the problem of poor rutting resistance of the traditional paving asphalt mixture, has better durability than the traditional road structure asphalt mixture, and has good social and economic effects.

[0024] 3. The new paving asphalt mixture of the application has excellent deformation capacity while having sufficient rutting resistance, can be used for road disease treatment and road structure layer paving, does not need to be rolled in the construction process, has fast molding speed, reduces the time of road disease treatment and structure layer paving, reduces the influence on traffic, has very wide application prospect, and has great popularization significance. BRIEF DESCRIPTION OF DRAWINGS

[0025] ​In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art of the present application, the drawings required to be used in the specific embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings described in the following are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0026] Figure 1 A molding diagram of the new cast asphalt mixture of Example 1;

[0027] Figure 2 A cross-sectional view of the new cast asphalt mixture of Example 1. DETAILED DESCRIPTION

[0028] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0029] It should be noted that the terms used herein are only for the purpose of describing the specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form also includes the plural form unless the context clearly indicates otherwise, and furthermore, it should be understood that when the terms "comprise" and / or "include" are used in the specification, there is a feature, step, operation, device, component and / or combination thereof.

[0030] The technical solutions of the present application will be described in detail below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the scope of protection of the present application.

[0031] Example 1

[0032] The new cast asphalt mixture of the present embodiment is made of the following components by weight: 100 parts of coarse aggregate, 15 parts of asphalt, and 17 parts of mineral powder; wherein the technical parameters of the asphalt are: dynamic viscosity at 60℃ greater than 580000 Pa·s (for example, 600000 Pa·s), softening point (ring and ball method) of 92℃, ductility (5℃, 5cm / min) of 34mm, and penetration (25℃, 100g, 5s) of 5.0mm; the coarse aggregate is composed of 63 parts of diabase coarse aggregate of 4.75-9.5mm and 37 parts of diabase coarse aggregate of 9.5-13.2mm, and the mineral powder is limestone mineral powder with a particle size of less than 0.075mm.

[0033] The preparation method of the new cast asphalt mixture of the embodiment comprises the following steps:

[0034] 1) Determine the viscosity-temperature curve of the above asphalt according to the asphalt rotation viscosity test, and further determine the mixing temperature T of the mixture M is 200℃;

[0035] 2) The above asphalt, coarse aggregate and mineral powder are respectively added to the oven and heated in stages for 4h, and the heating temperature is controlled at 180℃ for the first 3h and 200℃ for the last 1h;

[0036] 3) After heating, the coarse aggregate is placed in the mixer according to the weight part, mixed for 90s, so that the coarse aggregate is uniformly mixed; then the asphalt is added according to the weight part, mixed for 90s; pause mixing, then add the mineral powder according to the weight part, continue mixing for 90s, until the mixture is uniformly mixed; during the whole mixing process, the temperature of the mixer is controlled to keep at 220℃;

[0037] 4) The above mixed asphalt mixture is loaded into the rut plate template, the surface mixture of the rut plate is treated to make the surface flat, and then placed into the cast vibrating instrument for 110s of vibration, until the mortar fills the voids in the framework, that is, the new cast asphalt mixture is prepared, the void ratio is 0.910%, and the molding diagram and cross-sectional diagram are respectively shown in Figure 1 、 Figure 2 .

[0038] Example 2

[0039] The new cast asphalt mixture of the embodiment is made of the following components by weight: coarse aggregate 100 parts, asphalt 13 parts, and mineral powder 23 parts; wherein the technical parameters of the asphalt are the same as those of Example 1; the coarse aggregate is composed of diabase coarse aggregate of 4.75-9.5mm 62 parts and diabase coarse aggregate of 9.5-13.2mm 38 parts, and the mineral powder is limestone mineral powder with a particle size of less than 0.075mm.

[0040] The preparation method of the new cast asphalt mixture of the embodiment comprises the following steps:

[0041] 1) Determine the viscosity-temperature curve of the above asphalt according to the asphalt rotation viscosity test, and further determine the mixing temperature T of the mixture M is 200℃;

[0042] 2) The above asphalt, coarse aggregate and mineral powder are respectively added to the oven and heated in stages for 4h, and the heating temperature is controlled at 180℃ for the first 3h and 200℃ for the last 1h;

[0043] 3) After heating, the coarse aggregate is placed in the mixer according to the weight parts, and mixed for 90s to make the coarse aggregate mixed uniformly; then the asphalt is added according to the weight parts, and mixed for 90s; the mixing is paused, the mineral powder is added according to the weight parts, and the mixing is continued for 90s until the mixing is uniform; during the whole mixing process, the temperature of the mixer is controlled to be kept at 220°C;

[0044] 4) The mixed asphalt mixture is loaded into the rut plate template, the surface mixture of the rut plate is processed to make the surface flat, then placed into the pouring type vibrator and vibrated for 120s until the mortar fills the voids in the framework, thereby obtaining the new pouring type asphalt mixture, and the void ratio is 0.707%.

[0045] Example 3

[0046] The new pouring type asphalt mixture of the example is made of the following components by weight: coarse aggregate 100 parts, asphalt 15 parts, and mineral powder 15 parts; wherein the technical parameters of the asphalt are the same as those of Example 1; the coarse aggregate is composed of diabase coarse aggregate of 4.75-9.5mm 64 parts and diabase coarse aggregate of 9.5-13.2mm 36 parts, and the mineral powder is limestone mineral powder with a particle size of less than 0.075mm.

[0047] The preparation method of the new pouring type asphalt mixture of the example includes the following steps:

[0048] 1) The viscosity-temperature curve of the asphalt is determined according to the asphalt rotary viscosity test, and then the mixing temperature T of the mixture is determined M is 200°C;

[0049] 2) The asphalt, coarse aggregate and mineral powder are added into the oven respectively and heated in stages for 3h, the heating temperature of the first 2h is controlled to be 180°C, and the heating temperature of the last 1h is controlled to be 200°C;

[0050] 3) After heating, the coarse aggregate is placed in the mixer according to the weight parts, and mixed for 90s to make the coarse aggregate mixed uniformly; then the asphalt is added according to the weight parts, and mixed for 90s; the mixing is paused, the mineral powder is added according to the weight parts, and the mixing is continued for 90s until the mixing is uniform; during the whole mixing process, the temperature of the mixer is controlled to be kept at 220°C;

[0051] 4) The mixed asphalt mixture is loaded into the rut plate template, the surface mixture of the rut plate is processed to make the surface flat, then placed into the pouring type vibrator and vibrated for 90s until the mortar fills the voids in the framework, thereby obtaining the new pouring type asphalt mixture, and the void ratio is 0.449%.

[0052] Comparative Example 1

[0053] Except that SBS modified asphalt is used to replace the asphalt of Example 1, the rest is basically the same as Example 1; the technical parameters of the SBS modified asphalt of this comparative example are: dynamic viscosity at 60℃ is 270000 Pa·s, softening point (ring and ball method) is 89.5℃, ductility (5℃) is 35.8mm, penetration (25℃, 100g, 5s) is 5.1mm.

[0054] Comparative Example 2

[0055] Except that modified asphalt is used to replace the asphalt of Example 1, the rest is basically the same as Example 1; the technical parameters of the modified asphalt of this comparative example are: dynamic viscosity at 60℃ is 360000 Pa·s, softening point (ring and ball method) is 89.5℃, ductility (5℃) is 36.5mm, penetration (25℃, 100g, 5s) is 5.1mm.

[0056] Comparative Example 3

[0057] Except that ordinary asphalt is used to replace the asphalt of Example 1, the rest is basically the same as Example 1; the technical parameters of the ordinary asphalt of this comparative example are: dynamic viscosity at 60℃ is 236.8 Pa·s, softening point (ring and ball method) is 48℃, penetration (25℃, 100g, 5s) is 6.8mm.

[0058] Comparative Example 4

[0059] Except that fly ash is used to replace the mineral powder of Example 1, the rest is basically the same as Example 1.

[0060] Comparative Example 5

[0061] Except that the composition of coarse aggregate is different, the rest is basically the same as Example 1; the composition of coarse aggregate of this comparative example is: 29.33 parts of aggregate with particle size of 13.2-16mm, 19.69 parts of aggregate with particle size of 9.5-13.2mm, 20.94 parts of aggregate with particle size of 4.75-9.5mm and 30.04 parts of aggregate with particle size of 2.36-4.75mm.

[0062] Comparative Example 6

[0063] Except that the composition of coarse aggregate is different, the rest is basically the same as Example 1; the composition of coarse aggregate of this comparative example is: 16.8 parts of aggregate with particle size of 9.5-13.2mm, 28.3 parts of aggregate with particle size of 4.75-9.5mm, 20.9 parts of aggregate with particle size of 2.36-4.75mm, 15.1 parts of aggregate with particle size of 1.18-2.36mm, 10.8 parts of aggregate with particle size of 0.6-1.18mm and 8.2 parts of aggregate with particle size of 0.3-0.6mm.

[0064] Comparative Example 7

[0065] The rest is basically the same as example 1 except that the coarse aggregate composition is different; the coarse aggregate composition of the present control example is: 20.8 parts of aggregate with a particle size of 9.5-13.2 mm, 34.9 parts of aggregate with a particle size of 4.75-9.5 mm, 25.7 parts of aggregate with a particle size of 2.36-4.75 mm and 18.6 parts of aggregate with a particle size of 1.18-2.36.

[0066] Control example 8

[0067] The rest is basically the same as example 1 except that the coarse aggregate composition is different; the coarse aggregate composition of the present control example is: 100 parts of aggregate with a particle size of 9.5-13.2 mm.

[0068] Control example 9

[0069] The rest is basically the same as example 1 except that step 2) is different; step 2) of the present control example is as follows: the above-mentioned asphalt, coarse aggregate and mineral powder are added into an oven and heated for 4 h, and the heating temperature is controlled at 200 ℃.

[0070] Test example 1 high temperature stability test

[0071] According to the "Highway Engineering Asphalt and Asphalt Mixture Test Procedures" (JTG E20-2011), the rutting test is used to evaluate the high temperature stability of the cast asphalt mixture of each example and control example. The experimental temperature is 60 ℃, the test wheel pressure is 0.75 MPa, the test wheel moves uniformly on the same track line, and the test steps are in accordance with the requirements of the specification. The test results are shown in Table 1.

[0072] Table 1 Rutting test results

[0073]

[0074] In Table 1, "-" means not detected.

[0075] As can be seen from Table 1, the dynamic stability of the test piece designed by using the new cast asphalt mixture of the present application is greater than 3000 times / mm, which meets the high temperature stability performance of the pavement structure layer material, and is much better than the 300-800 times / mm of the ordinary cast asphalt mixture.

[0076] Test example 2 low temperature crack resistance test

[0077] According to the "Highway Engineering Asphalt and Asphalt Mixture Test Procedures" (JTG E20-2011), the small beam low temperature bending test is used to evaluate the low temperature crack resistance of the cast asphalt mixture of each example and control example. The test temperature is -10 ℃, the holding time is 3 h, and the loading rate is 50 mm / min. The test results are shown in Table 2.

[0078] Table 2 Small beam low temperature bending test results

[0079]

[0080] In Table 2, "-" represents undetected.

[0081] As shown in Table 2, the maximum bending tensile strain of the new paving asphalt mixture of the application can reach 4000 με or more, and the low-temperature bending performance is more excellent than that of the ordinary asphalt mixture.

[0082] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the application, but not to limit it; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A method for preparing a pouring asphalt mixture, characterized in that: The cast asphalt mixture is prepared from the following raw materials in parts by weight: 90-110 parts of coarse aggregate, 10-25 parts of asphalt, and 10-25 parts of mineral powder; wherein the particle size of the coarse aggregate is 4.75-13.2 mm, the dynamic viscosity of the asphalt at 60° C. is greater than 400,000 Pa·s, and the particle size of the mineral powder is less than 0.075 mm. The preparation method comprises the following steps in order: S1: Determine the mixing temperature T of the mixture based on the viscosity-temperature curve of asphalt M ℃; S2: Two-stage heating of asphalt, coarse aggregate and mineral powder respectively; S3: placing the heated coarse aggregate in a mixer according to weight for the first mixing, then adding asphalt for the second mixing, and then adding mineral powder for the third mixing; S4: The mixed mixture is placed into a formwork, and then placed in a vibrator for vibrating to obtain a pouring asphalt mixture; The coarse aggregate comprises, by weight: 60-70 parts of a first coarse aggregate of 4.75-9.5 mm and 30-40 parts of a second coarse aggregate of 9.5-13.2 mm; In step S2, the first stage heating temperature is controlled to be higher than the mixing temperature T M ℃ is 15-25 ℃ lower, the first heating time is 2-3 h; the second heating temperature is the mixing temperature T M ℃, the second heating time is 40-80 min.

2. The preparation method according to claim 1, characterized in that The coarse aggregate is diabase coarse aggregate.

3. The preparation method according to claim 1, characterized in that The mineral powder is limestone mineral powder.

4. The preparation method according to claim 1, wherein In step S3, the temperature of each mixing is controlled to be greater than the mixing temperature T M ℃ is 15-25 ℃ higher; the mixing time of each time is controlled to be 80-100 s.

5. The preparation method according to claim 1, wherein In step S4, the vibration time is controlled to be 90-120s.

6. The preparation method according to claim 1, characterized in that In step S4, the void ratio of the poured asphalt mixture is less than 1%.

7. Use of the pouring asphalt mixture prepared by the preparation method according to any one of claims 1 to 6 in the treatment of pavement defects or the paving of pavement structure layers.

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