CN111423156A - Anti-rutting drainage ultrathin overlay asphalt mixture and preparation method thereof - Google Patents

Abstract

The invention relates to an anti-rutting drainage ultra-thin cover asphalt mixture and a preparation method thereof, belonging to the technical field of road maintenance. The preparation method of the drainage ultra-thin finish asphalt mixture provided by the present invention includes the following steps: preparing aggregate, asphalt and filler; dividing the aggregate into coarse aggregate and fine aggregate, and determining the coarse aggregate and fine aggregate , the density of filler and asphalt, the volume method is used to determine the proportion of coarse and fine aggregates in the gradation, the porosity and the percentage of asphalt mass; according to the mass ratio of coarse and fine aggregates and the Fowler series, the drainage ultra-thin overlay asphalt mixture is completed. The grading design of the material is added, and the key sieve holes of the screen are added; the optimal asphalt quality percentage of the drainage ultra-thin finish asphalt mixture is determined. The asphalt mixture prepared by the preparation method provided by the invention has a large void ratio, many contacts between the coarse aggregates, good stability of the skeleton space network structure, strong inter-skeleton embedding force, and good drainage performance and anti-rutting ability.

Description

A kind of anti-rutting drainage ultra-thin finish asphalt mixture and preparation method thereof

technical field

The invention relates to an anti-rutting drainage ultra-thin cover asphalt mixture and a preparation method thereof, belonging to the technical field of road maintenance.

Background technique

With the continuous development of the economy and the deepening of the urbanization process, the traffic load is also increasing year by year, so people have higher and higher requirements for highway performance. In cloudy and rainy weather, the incidence of road accidents is much higher than that in sunny days, and vicious accidents such as serial rear-end collisions and water drifting occur frequently. Therefore, it is reasonable to use a drainage ultra-thin cover with a large structural void ratio and an obvious pavement drainage effect as the upper layer of the asphalt pavement.

The drainage ultra-thin surface asphalt mixture is easily damaged by water due to its large interconnected voids, and is easily damaged by water, such as spalling and loosening, and because it is located in the uppermost layer of the pavement structure, after direct contact with strong sunlight in summer, the temperature will rapidly increase. increase, the modulus and shear strength of the mixture decrease rapidly. If the anti-rutting ability of the drainage ultra-thin overlay asphalt mixture is insufficient, the road surface is prone to diseases such as waves, shifting, rutting and other diseases under the repeated action of the driving load, which affects the driving comfort and the anti-skid performance of the road surface, and affects the driving safety. Sexual threats. If the rutting resistance of the ultra-thin overlay asphalt mixture is good, it can bear the role of the traffic load, effectively reducing the rutting and other diseases of the underlying asphalt mixture, and because the ultra-thin overlay asphalt mixture has good flatness And anti-skid performance, road driving comfort and safety are improved.

Therefore, it is of great practical significance to conduct in-depth research on the improvement of the rutting resistance of the drainage ultra-thin finish asphalt mixture.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a method for preparing a rutting-resistant ultra-thin surface asphalt mixture with drainage.

In order to achieve the above purpose, the technical solution adopted in the present invention is: a preparation method of a drainage ultra-thin topping asphalt mixture, comprising the following steps:

(1) Prepare raw materials: aggregate, asphalt and filler;

(2) Divide the aggregates into coarse aggregates and fine aggregates, determine the densities of coarse aggregates, fine aggregates, fillers and asphalt, and use the volume method to determine the proportion of coarse and fine aggregates in the gradation, and the drainage ultra-thin cover The porosity of the asphalt mixture and the percentage content of the asphalt mass;

(3) According to the mass ratio of coarse and fine aggregates and the Fowler series, the gradation design of the drainage ultra-thin topping asphalt mixture is completed, and the key sieve holes of the screen are added;

(4) Determining the optimal asphalt mass percentage content of the drainage ultra-thin finish asphalt mixture, and then the drainage ultra-thin finish asphalt mixture can be obtained.

The preparation method provided by the present invention adopts the volume method to optimize the gradation design of the asphalt mixture, which can improve the embedding force between the coarse aggregates and the stability of the skeleton space network structure, and the prepared ultra-thin drainage surface Asphalt mixture has a strong ability to resist permanent deformation.

As a preferred embodiment of the preparation method of the present invention, in step (1), the aggregate is diabase, the asphalt shown is high-viscosity asphalt (provided by Shell Asphalt Co., Ltd.), and the filler is alkaline limestone ore powder (to remove impurities in the mineral powder); the diabase includes crushed stone with a particle size of 3-5mm, 5-10mm and stone chips with a particle size of 0-3mm.

As a preferred embodiment of the preparation method of the present invention, in step (2), the bulk density of the coarse aggregate is 2.90 g/cm ³ , and the bulk density in a tamped state is 1.72 g/cm ³ ; The apparent relative density of the fine aggregate was 2.93 g/cm ³ ; the relative density of the asphalt was 1.023 g/cm ³ , and the relative density of the filler was 2.864 g/cm ³ .

As a preferred embodiment of the preparation method of the present invention, in step (2), the porosity of the drainage ultra-thin surface asphalt mixture is 18%-23%, and the mass percentage of the asphalt is 3.9%-5.1% %.

The division of coarse and fine aggregates is made according to the specification (JTG E42-2005 "Highway Engineering Aggregate Test Regulations"). The proportion of coarse and fine aggregates in the gradation varies according to the selected gradation. When the porosity of the ultra-thin surface asphalt mixture with drainage is satisfied, the porosity of the asphalt mixture is 18%-23%, and the mass percentage of the asphalt is 3.9%. -5.1%, the gradation proportion of the coarse and fine aggregates can be obtained.

As a preferred embodiment of the preparation method of the present invention, in step (2), the volume method is used to determine the ratio of coarse and fine aggregates, and the mass percentage content of coarse and fine aggregates is obtained by formula ① and formula ②:

①q _c +q _f +q _p =100;

③VCA _DRC = (1-ρ/ρ _b )х100

Among them, q _c , q _f , q _p , and q _a are the mass percentages of coarse aggregate, fine aggregate, mineral powder and asphalt, respectively, VCA _DRC is the porosity of coarse aggregate (%), and VCA is obtained according to formula ③ _DRC , Vv is the design porosity (%), ρ is the bulk density (g/cm ³ ) of the coarse aggregate in the tamped state; ρ _b is the synthetic gross bulk density of the coarse aggregate; ρ _af is the apparent bulk density of the fine aggregate Relative density (g/cm ³ ); ρ _a is the relative density of asphalt (g/cm ³ ); ρ _f is the relative density of mineral powder (g/cm ³ ).

As a preferred embodiment of the preparation method of the present invention, in step (3), the Fowler series design is specifically as follows:

Wherein, P is the percentage (%) of the aggregate passing through the mesh size d; d is the mesh size (mm); D is the maximum particle size of the aggregate (mm); n is the index, 0.3≤n≤0.5.

As a preferred embodiment of the preparation method of the present invention, in step (3), the gradation of the drainage ultra-thin finish asphalt mixture is as follows:

Sieve hole/mm 13.2 9.5 8 6.7 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Passing rate/% 100 94.8 86.2 72.7 20.9 15.4 13.4 10.7 7.6 6.1 5

.

As a preferred embodiment of the preparation method of the present invention, in step (3), the mesh apertures of the screen mesh are 13.2mm, 9.5mm, 8.0mm, 6.7mm, 4.75mm, 2.36mm, 1.18mm, 0.6mm , 0.3mm, 0.15mm or 0.075mm.

As a preferred embodiment of the preparation method of the present invention, in step (3), the specific operation of the key sieve holes added to the sieve is as follows: adding a hole diameter of 6.7mm and 8mm between the sieve holes of 4.75mm-9.5mm of the two key sieve holes.

As a preferred embodiment of the preparation method of the present invention, in step (4), the leakage and scattering comprehensive experimental method is used to determine the optimal asphalt mass percentage content of the drainage ultra-thin finish asphalt mixture; the drainage ultra-thin The optimum bitumen quality percentage of the surface asphalt mixture is 4.5%.

High-temperature rutting test, low-temperature trabecular bending, immersion Marshall test, freeze-thaw splitting test and structural depth test were used as routine road performance tests.

Another object of the present invention is to provide a drainage ultra-thin finish asphalt mixture prepared by the preparation method.

The drainage ultra-thin cover asphalt mixture of the invention improves the high temperature stability and rutting resistance of the asphalt mixture.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The present invention provides a method for preparing a drainage ultra-thin topping asphalt mixture, wherein the prepared asphalt mixture has a large porosity, a large number of contacts between the coarse aggregates, and good stability of the skeleton space network structure, The inter-frames have strong embedding force, good drainage performance and anti-rutting ability, and the road surface is not prone to cracks, ruts, potholes and other diseases, improving driving comfort and safety;

(2) The drainage ultra-thin finish asphalt mixture prepared by the preparation method of the present invention can effectively improve the high temperature stability and rutting resistance of the drainage ultra-thin finish asphalt mixture;

(3) The drainage ultra-thin finish asphalt mixture prepared by the preparation method of the present invention, its high temperature stability performance, low temperature crack resistance performance, water damage resistance ability and anti-skid performance all meet the requirements of the specification, and because its It has good drainage performance and anti-rutting ability, and the road surface is not prone to cracks, ruts, potholes and other diseases. Applying the drainage ultra-thin cover asphalt mixture of the present invention to the road surface can improve driving comfort and safety. .

Description of drawings

Fig. 1 is a kind of preparation process flow chart of the anti-rutting drainage ultra-thin finish asphalt mixture provided by the present invention.

Detailed ways

In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below with reference to specific embodiments.

Example 1

The present embodiment is a preparation method of a rutting-resistant ultra-thin surface asphalt mixture with drainage provided by the present invention, comprising the following steps:

(1) Prepare raw materials: aggregate (10mm diabase crushed stone), high-viscosity asphalt (provided by Shell Asphalt Co., Ltd.), alkaline limestone ore powder (removal of impurities in the ore powder);

(2) Divide the aggregates into coarse aggregates and fine aggregates, and determine the densities of coarse aggregates, fine aggregates, fillers and asphalt (the gross bulk density of coarse aggregates is 2.90 g/cm ³ , and the The bulk density is 1.72g/cm ³ ; the apparent relative density of fine aggregate is 2.93g/cm ³ ; the relative density of high-viscosity asphalt is 1.023g/cm ³ , the relative density of alkaline limestone powder is 2.864g/cm ³ ) , the mass ratio of coarse and fine aggregates is determined by the volume method, and the mass percentage of coarse and fine aggregates is obtained by formula ① and formula ②:

①q _c +q _f +q _p =100;

③VCA _DRC = (1-ρ/ρ _b )х100;

Among them, q _c , q _f , q _p , and q _a are the mass percentages of coarse aggregate, fine aggregate, mineral powder and asphalt respectively, VCA _DRC is the coarse aggregate porosity (%), and Vv is the design porosity (%), ρ is the bulk density of the coarse aggregate in the tamped state (g/cm ³ ); ρ _b is the synthetic gross bulk density of the coarse aggregate; ρ _af is the apparent relative density of the fine aggregate (g/cm ^{3 )} ); ρ _a is the relative density of asphalt (g/cm ³ ); ρ _f is the relative density of mineral powder (g/cm ³ ); According to formula ① and ②, the mass percentage content of coarse aggregate _{q c} is 84.6%, and the amount of fine aggregate q _c is 84.6%. The aggregate mass percentage q _f is 10.4%, according to formula ③, it can be seen that the VCA _DRC is 40.7%;

其中，P是筛孔尺寸d的集料通过百分率(％)；d是筛孔尺寸(mm)；D是集料的最大粒径(mm)；n是指数；P和d如下表1所述，D＝10mm，n＝0.5；(3) According to the proportion of coarse and fine aggregates and the Fowler series, the gradation design of the drainage ultra-thin overlay asphalt mixture is completed, and the key sieve holes of the screen are added; the Fowler series design is as follows:

Where, P is the percentage (%) of the aggregate passing through the mesh size d; d is the mesh size (mm); D is the maximum particle size of the aggregate (mm); n is the index; P and d are as described in Table 1 below , D=10mm, n=0.5;

The gradation of the drainage ultra-thin finish asphalt mixture is shown in Table 1 below:

Table 1 Gradation of drainage ultra-thin finish asphalt mixture

Sieve hole/mm 13.2 9.5 8 6.7 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Passing rate/% 100 94.8 86.2 72.7 20.9 15.4 13.4 10.7 7.6 6.1 5

(4) Determine the optimal asphalt mass percentage content of the drainage ultra-thin finish asphalt mixture, and then the drainage ultra-thin finish asphalt mixture can be obtained; select the leakage and scattering comprehensive test method to determine the ultra-thin finish The optimum amount of asphalt for the asphalt mixture was mixed with 5 groups of asphalt mixtures with an amount of 3.9%, 4.2%, 4.5%, 4.8% and 5.1%. The Marshall compactor was used to form the test piece, and the number of compactions was 25 on both sides. Second, put the molded specimen into the Los Angeles attrition machine and rotate 300 laps at 33 r/min. The ratio of the lost mass to the original mass of the specimen is taken as the scattering loss. The scattering and leakage test results of different asphalt mixtures are shown in Table 2. As shown in Table 3, the optimal asphalt dosage volume parameter table of asphalt mixture is shown in Table 3.

Table 2 Optimum asphalt content range for asphalt mixture

When the amount of asphalt is in the range of 4.4%-4.6%, the rate of change of leakage loss and scattering loss is quite different, and because the leakage loss and scattering loss of asphalt mixture at this time both meet the specification requirements, so the amount of asphalt is 4.5% is the optimum asphalt dosage for asphalt mixture.

Table 3 Asphalt mixture volume parameters

Experimental example 1

In this experimental example, according to the preparation method of the rutting-resistant ultra-thin surface asphalt mixture with drainage described in Example 1, the optimal amount of asphalt was used to obtain the ultra-thin surface asphalt mixture with drainage. Trabecular bending test, immersion Marshall test, freeze-thaw splitting test and structural depth test verify the road performance of the drainage ultra-thin finish asphalt mixture.

1. Rutting dynamic stability test

According to the requirements of Asphalt and Asphalt Mixture Test Regulations (JTGF20-2011) T0719, three sets of rutting tests were carried out under the conditions of 60±1℃ and 0.7±0.05MPa (the three sets of rutting tests were all asphalt mixtures prepared in the same batch , for the repeatability test), the test results are shown in Table 4.

Table 4 Rutting dynamic stability test results

The test results in Table 4 show that the drainage ultra-thin finish asphalt mixture of Example 1 of the present invention meets the specification requirements and has good high temperature stability.

2. Low temperature trabecular bending test

According to the requirements of T0715 of Asphalt and Asphalt Mixture Test Regulations (JTGF20-2011), the low temperature bending test was carried out under the conditions of -10℃ and 50mm/min loading rate (the following 4 sets of test pieces are asphalt mixtures prepared from the same batch material, which is a repeatable test), and the test results are shown in Table 5.

Table 5 Results of low temperature trabecular bending test

The results in Table 5 show that the low-temperature bending failure strain of the drainage ultra-thin finish asphalt mixture of Example 1 of the present invention is greater than 2500, which meets the specification requirements.

3. Water stability test

The water stability performance of the asphalt mixture was tested by the water immersion Marshall test and the freeze-thaw splitting test according to the optimal asphalt dosage and gradation. The results are shown in Table 6 and Table 7, respectively.

Table 6 Water immersion Marshall test results

Table 7 Freeze-thaw split test results

The test results in Tables 6 and 7 show that the water-damage resistance and low-temperature crack resistance of the drainage ultra-thin finish asphalt mixture of Example 1 of the present invention meet the specification requirements.

4. Structural depth test

The surface structure depth of the asphalt mixture was measured by the sand topping method. The following three groups of test specimens were the asphalt mixture prepared in the same batch and were repeated tests. The test results are shown in Table 8.

Table 8 Results of structural depth test

Through the road performance test verification of the drainage ultra-thin finish asphalt mixture of Experimental Example 1, it shows that the rutting-resistant drainage ultra-thin finish asphalt mixture prepared by this method has high temperature stability, low temperature crack resistance, water resistance. Both the damage ability and anti-skid performance meet the requirements of the specification, and because of its good drainage performance and anti-rutting ability, the road surface is not prone to cracks, ruts, potholes and other diseases. The mixture is applied to the road surface to improve driving comfort and safety.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the protection scope of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that, The technical solutions of the present invention may be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims (9)

1. The preparation method of the drainage ultrathin overlay asphalt mixture is characterized by comprising the following steps of:

(1) preparing raw materials: aggregate, asphalt and filler;

(2) dividing aggregates into coarse aggregates and fine aggregates, determining the densities of the coarse aggregates, the fine aggregates, the filler and the asphalt, and determining the proportion of the coarse aggregates and the fine aggregates in the gradation, the void ratio of the drainage ultrathin overlay asphalt mixture and the mass percentage of the asphalt by adopting a volume method;

(3) finishing the grading design of the drainage ultrathin overlay asphalt mixture according to the mass ratio of coarse aggregates to fine aggregates and the Fowler series, and adding the key sieve pores of the sieve;

(4) and determining the optimal asphalt mass percentage content of the drainage ultrathin overlay asphalt mixture to obtain the drainage ultrathin overlay asphalt mixture.

2. The method according to claim 1, wherein in the step (1), the aggregate is diabase, the asphalt is high-viscosity asphalt, and the filler is basic limestone ore powder; the diabase comprises 3-5mm and 5-10mm of broken stone and 0-3mm of stone chips.

3. The method of claim 1, wherein in the step (2), the coarse aggregate has a bulk density of 2.90g/cm³Bulk density in the tamped state of 1.72g/cm³(ii) a The fine aggregate has an apparent relative density of 2.93g/cm³(ii) a The relative density of the asphalt is 1.023g/cm³The relative density of the filler is 2.864g/cm³。

4. The preparation method according to claim 1, wherein in the step (2), the void ratio of the drainage ultrathin overlay asphalt mixture is 18-23%, and the content of asphalt in percentage by mass is 3.9-5.1%.

5. The method of claim 1, wherein in step (3), the drainage ultra-thin overlay asphalt mix is graded as follows:

mesh/mm 13.2 9.5 8 6.7 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Through rate/%) 100 94.8 86.2 72.7 20.9 15.4 13.4 10.7 7.6 6.1 5

。

6. The method according to claim 1, wherein in the step (3), the mesh has a mesh opening size of 13.2mm, 9.5mm, 8.0mm, 6.7mm, 4.75mm, 2.36mm, 1.18mm, 0.6mm, 0.3mm, 0.15mm, or 0.075 mm.

7. The method according to claim 1, wherein in the step (3), the operation of adding the key holes into the screen is to add two key holes with the hole diameter of 6.7mm and 8mm between the holes with the hole diameter of 4.75mm to 9.5 mm.

8. The preparation method according to claim 1, wherein in the step (4), the optimal asphalt mass percentage of the drainage ultrathin overlay asphalt mixture is determined by a leakage and scattering comprehensive experiment method; the optimal asphalt mass percentage content of the drainage ultrathin overlay asphalt mixture is 4.5%.

9. The drainage ultrathin overlay asphalt mixture prepared by the preparation method of any one of claims 1 to 8.

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