阅读说明：本技术 一种抗车辙的排水性超薄罩面沥青混合料及其制备方法 (Anti-rutting drainage ultrathin overlay asphalt mixture and preparation method thereof ) 是由 黄文柯 崔文天 吴旷怀 蔡旭 于 2020-03-23 设计创作，主要内容包括：本发明涉及一种抗车辙的排水性超薄罩面沥青混合料及其制备方法,属于道路养护技术领域。本发明提供的排水性超薄罩面沥青混合料的制备方法,包括如下步骤：准备集料、沥青和填料；将集料划分为粗集料和细集料,确定粗集料、细集料、填料和沥青的密度,采用体积法确定粗细集料占级配比例、空隙率和沥青质量百分含量；根据粗细集料的质量比和福勒级数,完成排水性超薄罩面沥青混合料的级配设计,并加入筛网的关键筛孔；确定排水性超薄罩面沥青混合料的最佳沥青质量百分含量。发明提供的制备方法制备获得的沥青混合料空隙率较大,粗骨料间接触点多,骨架空间网络结构稳定性好,骨架间嵌挤力强,具有很好的排水性能和抗车辙能力。(The invention relates to an anti-rutting drainage ultrathin overlay asphalt mixture and a preparation method thereof, belonging to the technical field of road maintenance. The preparation method of the drainage ultrathin overlay asphalt mixture provided by the invention comprises the following steps: preparing aggregate, asphalt and filler; 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 to the coarse aggregates, the proportion of the fine aggregates to the fine aggregates, the void ratio of the coarse aggregates to the fine aggregates and the mass percentage of the asphalt by a volume method; 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; and determining the optimal asphalt mass percentage content of the drainage ultrathin overlay asphalt mixture. The asphalt mixture prepared by the preparation method provided by the invention has the advantages of large void ratio, more indirect contacts of coarse aggregate, good stability of a framework space network structure, strong embedding and squeezing force among frameworks, and good drainage performance and anti-rutting capability.)

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.

Technical Field

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

Background

With the continuous development of economy and the increasing of urbanization process, traffic load is increased year by year, so that the performance requirements of people on roads are higher and higher. In rainy days, the incidence rate of road accidents is far greater than that in sunny days, serious accidents such as chain rear-end collisions and water drift occur frequently, and the main reason of high accidents is that the friction coefficient of the road surface is obviously reduced due to a large amount of water accumulated on the road, and the braking distance is greatly prolonged. Therefore, it is reasonable to use the drainage ultrathin overlay with large structural void ratio and obvious road surface drainage effect as the upper layer of the asphalt pavement.

The drainage ultrathin overlay asphalt mixture is easy to be damaged by water to peel off, loosen and the like due to the existence of larger communication gaps, and the temperature is rapidly increased and the modulus and the shear strength of the mixture are rapidly reduced after the mixture is directly contacted with strong sunlight in summer because the drainage ultrathin overlay asphalt mixture is positioned on the uppermost layer of a pavement structure. If the anti rutting ability of ultra-thin overlay bituminous mixture of drainage is not enough, just the road surface just produces easily such diseases as wave, lapse, rutting under the repeated action of driving load, influences the skid resistance performance on travelling comfort and road surface, causes the threat to driving safety. If the anti-rutting capability of the ultrathin overlay asphalt mixture is better, the ultra-thin overlay asphalt mixture can bear the action of driving load, effectively reduce the diseases such as rutting and the like of the lower-layer asphalt mixture, and because the ultrathin overlay asphalt mixture has good flatness and anti-sliding performance, the driving comfort and the safety of the road surface are improved.

Therefore, the method has important practical significance for deeply researching the improvement of the anti-rutting capability of the drainage ultrathin overlay asphalt mixture.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a preparation method of an anti-rutting drainage ultrathin overlay asphalt mixture.

In order to achieve the purpose, the invention adopts the technical scheme that: a preparation method of a drainage ultrathin overlay asphalt mixture comprises the following steps:

(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 proportion of coarse and fine aggregates and the Fowler series, and adding key sieve pores of a 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.

According to the preparation method provided by the invention, the asphalt mixture is subjected to optimized grading design by adopting a volume method, the embedding force among coarse aggregates and the stability of a framework space network structure can be improved, and the prepared water-draining ultrathin overlay asphalt mixture has stronger capacity of resisting permanent deformation.

As a preferred embodiment of the preparation method of the present invention, in step (1), the aggregate is diabase, the asphalt is high-viscosity asphalt (provided by shell asphalt company, ltd), and the filler is alkaline limestone ore powder (for removing impurities from the ore powder); the diabase comprises 3-5mm and 5-10mm of broken stone and 0-3mm of stone chips.

As a preferred embodiment of the preparation method of the present invention, in the step (2), the coarse aggregate has a gross 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。

As a preferable embodiment of the preparation method, in the step (2), the voidage of the drainage ultrathin overlay asphalt mixture is 18-23%, and the asphalt content is 3.9-5.1% by mass.

The coarse and fine aggregates are divided according to the standard (JTG E42-2005 Highway engineering aggregate test Specification), aggregates with the grain size of more than or equal to 2.36mm are coarse aggregates, and aggregates with the grain size of less than 2.36mm are fine aggregates. The proportion of the coarse and fine aggregates in the grading is changed according to different selected grading, and when the porosity of the drainage ultrathin overlay asphalt mixture is 18-23% and the asphalt mass percentage is 3.9-5.1%, the proportion of the coarse and fine aggregates in the grading can be obtained.

As a preferred embodiment of the preparation method of the present invention, in step (2), the coarse and fine aggregate proportion is determined by a volume method, and specifically, the mass percentage of the coarse and fine aggregates is obtained by formulas ① and ②:

①q_c+q_f+q_p＝100；

③VCA_DRC＝(1-ρ/ρ_b)х100

wherein q is_c、q_f、q_p、q_aRespectively the mass percentage of coarse aggregate, fine aggregate, mineral powder and asphalt, VCA_DRCIs the coarse aggregate porosity (%), VCA obtained according to formula ③_DRCVv is the design porosity (%), and ρ is the bulk density (g/cm) of the coarse aggregate in the compacted state³)；ρ_bIs the bulk density of the coarse aggregate synthetic wool; rho_afIs the apparent relative density (g/cm) of the fine aggregate³)；ρ_aIs the relative density (g/cm) of the asphalt³)；ρ_fIs the relative density (g/cm) of the ore powder³)。

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

wherein P is the aggregate passage percentage (%) for the mesh size d; d is the mesh size (mm); d is the maximum particle size (mm) of the aggregate; n is an index, n is more than or equal to 0.3 and less than or equal to 0.5.

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

。

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

As a preferred embodiment of the preparation method of the invention, in the step (3), the key screen holes added into the screen are specifically operated by adding two key screen holes with the hole diameter of 6.7mm and 8mm between the screen holes with the hole diameter of 4.75mm-9.5 mm.

As a preferred embodiment of the preparation method, in the step (4), determining the optimal asphalt mass percentage of the drainage ultrathin overlay asphalt mixture by adopting a leakage and scattering comprehensive experiment method; the optimal asphalt mass percentage content of the drainage ultrathin overlay asphalt mixture is 4.5%.

A high-temperature track test, a low-temperature small beam bending test, a water immersion Marshall test, a freeze-thaw splitting test and a construction depth test are adopted as a conventional pavement performance test.

The invention also aims to provide the drainage ultrathin overlay asphalt mixture prepared by the preparation method.

The drainage ultrathin overlay asphalt mixture improves the high-temperature stability and the anti-rutting capability of the asphalt mixture.

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the preparation method of the drainage ultrathin overlay asphalt mixture, the prepared asphalt mixture has the advantages of large void ratio, more indirect contacts of coarse aggregates, good structural stability of a framework space network, strong embedding and squeezing force among frameworks, good drainage performance and anti-rutting capability, difficulty in occurrence of diseases such as cracks, ruts and pits on the pavement, and improvement of driving comfort and safety;

(2) the drainage ultrathin overlay asphalt mixture prepared by the preparation method can effectively improve the high-temperature stability and the anti-rutting capability of the drainage ultrathin overlay asphalt mixture;

(3) the drainage ultrathin overlay asphalt mixture prepared by the preparation method provided by the invention has the advantages that the high-temperature stability, the low-temperature crack resistance, the water damage resistance and the skid resistance meet the standard requirements, and because the drainage performance and the track resistance are better, the defects such as cracks, tracks, pits and the like are not easy to occur on the pavement, the drainage ultrathin overlay asphalt mixture provided by the invention is applied to the pavement, and the driving comfort and the safety can be improved.

Drawings

FIG. 1 is a flow chart of a preparation process of the anti-rutting drainage ultrathin overlay asphalt mixture.

Detailed Description

To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples.