阅读说明：本技术 细粒式薄层罩面沥青混合料 (Fine-grained thin-layer overlay asphalt mixture ) 是由 章清涛 高岳峰 胡家波 马祥辉 韦金城 许玉和 姚望 符东绪 王晓然 崔风华 杨 于 2021-08-05 设计创作，主要内容包括：本发明公开了细粒式薄层罩面沥青混合料,属于道路路面材料技术领域。所述混合料包括粗骨料、细集料、填料、胶结料及稳定剂,其特征在于：设置8mm筛孔作为最大公称粒径,以关键筛孔矿料的通过百分率计,其级配范围为：11mm,100％；8.0mm,90％～100％；2.36mm,24％～34％；0.075mm10％～14％。与现有技术相比,将本发明所述混合料用于高等级公路中维修养护过程中时,能够有效减少工程投资,而且具有良好的耐久性、良好的抗滑性及降低路面噪音的功能。(The invention discloses a fine-grained thin-layer overlay asphalt mixture, belonging to the technical field of road pavement materials. The mixture comprises coarse aggregate, fine aggregate, filler, cementing material and stabilizer, and is characterized in that: setting 8mm sieve pores as the maximum nominal particle size, and the grading range of the mineral aggregate in the key sieve pores is as follows by percentage: 11mm, 100%; 8.0mm, 90% -100%; 2.36mm, 24% -34%; 0.075mm 10% -14%. Compared with the prior art, when the mixture is used in the maintenance process of a high-grade highway, the engineering investment can be effectively reduced, and the mixture has the functions of good durability, good skid resistance and pavement noise reduction.)

1. The fine grain type thin layer overlay asphalt mixture comprises coarse aggregate, fine aggregate, filler, cementing material and stabilizer, and is characterized in that: set up 11mm sieve mesh as the maximum particle size, 8mm sieve mesh as the biggest nominal particle size to the percent of passing through of key sieve mesh mineral aggregate, its gradation scope is: 11mm, 100%; 8.0mm, 90% -100%; 2.36mm, 24% -34%; 0.075mm 10% -14%.

2. A fine-grained thin-layer overlay asphalt mixture according to claim 1, characterized in that the gradation ranges, in percent passage of the mineral aggregates of each grain size:

11mm，100％；8.0mm，90～100％；4.75mm，32～64％；2.36mm，24～34％；1.18mm，18～28％；0.6mm，15～24％；0.3mm，13～20％；0.15mm，11～16％；0.075mm，10～14％。

3. the fine-grained thin-layer overlay asphalt mixture according to claim 1 or 2, wherein hard igneous rock of 3-8 mm and 3-5 mm is used as coarse aggregate, hard igneous rock machine-made sand of 0-3mm is used as fine aggregate, and limestone mineral powder is used as filler.

4. The fine-grained thin-layer overlay asphalt mixture according to claim 3, wherein the weight ratio of 3-8 mm coarse aggregate, 3-5 mm coarse aggregate, 0-3mm fine aggregate and filler is (45-55): (11-21): (18-28): (10-13).

5. A fine-grained thin-layer overlay asphalt mixture according to claim 3, wherein the filler is admixed with 10-20% of quicklime or slaked lime.

6. The fine-grained thin-layer overlay asphalt mixture according to claim 1 or 2, wherein the stabilizer is lignin, mineral or polymer fiber, and the stabilizer accounts for 0.3-0.5% of the mass of the mixture;

the cementing material is SBS modified asphalt, high-viscosity high-elasticity modified asphalt or SBS and rubber composite modified asphalt, and accounts for 6.2-6.7% of the mass of the mixture.

7. A fine-grained thin-layer overlay asphalt mixture according to claim 1 or 2, wherein the mixture design void fraction is 3.5% to 4.0%, the mineral aggregate void fraction is not less than 18%, and the void fraction after field compaction is 4.0% to 5.0%.

Technical Field

The invention relates to the field of pavement materials, in particular to a fine-grained thin-layer overlay asphalt mixture.

Background

In the prior art, the mixture which is recommended by the national standard and is suitable for the surface layer of the asphalt pavement mainly comprises a fine grain type and a sand grain type. For the hot-mixing hot-paving dense-graded asphalt mixture, the compacted thickness of one layer of the asphalt layer is not less than 2.5-3.0 times of the nominal maximum particle size of the aggregate. Therefore, the design thickness of the current high-grade highway pavement is usually 40mm, and the types of common mixed materials are AC-13 and SMA-13. Although the designed thickness of the pavement can be reduced to 20-30mm by AC-10 and AC-5, the high-temperature performance is insufficient due to insufficient framework structure of the dense grading, the skid resistance is insufficient due to small macroscopic structure of the dense grading surface, the driving safety is affected, the high-grade pavement is generally used for low-grade roads or urban non-motor vehicle lanes, and the surface layer of the high-grade road basically does not adopt the two mixed material forms. The design thickness of the SMA-10 can reach 30mm, and compared with the SMA-13, although the thickness is reduced by 10mm, the SMA-10 has the following two defects: firstly, the consumption of the asphalt of the SMA-10 is 0.2-0.3% higher than that of the SMA-13, and the difference between the consumption of the asphalt and the construction cost of the SMA-13 is not large from the economic point of view; secondly, the minimum milling thickness of the original pavement is 30mm, so that interlayer is formed, the overall durability is not favorable, and therefore, SMA-13 with the thickness of 40mm is selected for road surface finish maintenance in actual operation.

Disclosure of Invention

The technical task of the invention is to provide a fine-grained thin-layer overlay asphalt mixture aiming at the defects of the prior art. When the mixture is used in the maintenance process of a high-grade highway, the engineering investment can be effectively reduced, and the mixture has the functions of good durability, good skid resistance and pavement noise reduction.

The technical task of the invention is realized by the following modes: the fine grain type thin layer overlay asphalt mixture comprises coarse aggregate, fine aggregate, filler, cementing material and stabilizer, and is characterized in that: set up 11mm sieve mesh as the maximum particle size, set up 8mm sieve mesh as the biggest nominal particle size to the percent of passing through of key sieve mesh mineral aggregate, its gradation scope is: 11mm, 100%; 8.0mm, 90% -100%; 2.36mm, 24% -34%; 0.075mm 10% -14%.

Preferably, the gradation range of the mixture of the invention is as follows according to the passing percentage of the mineral aggregate with each particle size: 11mm, 100%; 8.0mm, 90-100%; 4.75mm, 32-64%; 2.36mm, 24-34%; 1.18mm, 18-28%; 0.6mm, 15-24%; 0.3mm, 13-20%; 0.15mm, 11-16%; 0.075mm, 10-14%.

Preferably, hard igneous rock with the thickness of 3-8 mm and the thickness of 3-5 mm is used as coarse aggregate, machine-made sand with the thickness of 0-3mm is used as fine aggregate, and limestone mineral powder is used as filler.

The hard igneous rock is basalt and/or diabase and the like.

Preferably, the weight ratio of 3-8 mm coarse aggregate, 3-5 mm coarse aggregate, 0-3mm fine aggregate and filler is (45-55): 11-21): 18-28): 10-13, and particularly preferably is (50-55): 14-16): 21-23): 10-11.

Preferably, 10-20% of quicklime powder or slaked lime powder is added into the filler.

Preferably, the stabilizer is lignin, mineral or polymer fiber, and accounts for 0.3-0.5% of the mass of the mixture.

Preferably, the cementing material is SBS modified asphalt, high-viscosity high-elasticity modified asphalt or SBS and rubber composite modified asphalt, and the cementing material accounts for 6.2-6.7% of the mass of the mixture.

Preferably, the designed porosity of the mixture is 3.5-4.0%, the mineral aggregate porosity is not less than 18%, and the porosity after the on-site compaction is 4.0-5.0%.

When the mixture is used for road surface construction, the paving steps are as follows:

s1, finely milling an original road surface, wherein milling thickness is strictly controlled to be 15-20 mm, and the situation that an original surface layer is too thin to form a thin interlayer after milling is avoided;

s2, cleaning and milling the milled surface after milling;

s3, the mixing process of the fine-grain type thin-layer overlay asphalt mixture follows the following steps: weighing aggregate → putting fiber → metering asphalt → mixing mixture → loading mixture, controlling the heating temperature of the aggregate to be 190-220 ℃ and the heating temperature of the asphalt to be 165-175 ℃, and considering that the temperature loss is fast during the construction of thin-layer mixture, the discharging temperature of the mixture is preferably controlled to be 180-185 ℃;

s4, spreading the hot asphalt macadam seal, namely adopting a synchronous macadam seal spreading vehicle, wherein the hot asphalt is SBS modified asphalt, and the spreading amount is preferably 1.0-1.2 Kg/m²The crushed stone is 4.75-9.5 mm crushed stone which is pre-mixed by adding 0.3-0.5% of petroleum asphalt in the dust removal of the mixing station, and the spreading amount of the crushed stone is preferably 5.5-6.5 Kg/m²Carrying out pressure stabilization for 1-2 times by using a light rubber wheel;

and S5, after the hot asphalt macadam seal coat is finished, a paver is in place to preheat for at least 1h, the temperature of an ironing plate is not lower than 100 ℃, mixed material paving is carried out, the paving speed is 3-4 m/min, and a fine grain type thin-layer cover coat with the thickness of 25-30 mm is formed after compaction.

Compared with the prior art, the fine-grained thin-layer overlay asphalt mixture has the following outstanding beneficial effects:

through a large number of tests, the nominal maximum particle size is determined to be 8.0mm, the thickness can be 2.0-2.5 cm, compared with the thickness of SMA-10, the thickness is required to be 2.5-3.0 cm, the thickness can be reduced by 1cm, the good high-temperature stability of the SMA mixture is ensured, and the paving thickness of the mat coat pavement layer is greatly reduced.

And (II) the coarse aggregate above the 2.36mm sieve pore accounts for about 70, has rough surface, has good skid resistance and can reduce the noise in the driving process.

And thirdly, when the pavement is maintained, the milling thickness can be reduced, so that an interlayer is avoided, the integral durability is facilitated, and the maintenance cost is low.

Drawings

FIG. 1 is a grading diagram of a fine-grained thin-layer overlay asphalt mixture SMA8 using basalt stone in the examples.

FIG. 2 is a graph of the grading of a fine-grained thin-coated asphalt mixture SMA8 using diabase rock in the examples.

Detailed Description

The fine-grained thin-layer overlay asphalt mixture according to the invention is described in detail below in the following examples with reference to the drawing of the description.

The first embodiment is as follows:

the method comprises the following steps of (I) taking 3-8 mm and 3-5 mm basalt broken stones as coarse aggregates, taking 0-3mm basalt machine-made sand as fine aggregates, and taking limestone mineral powder as a filler.

The weight ratio of each level of mineral aggregate is as follows:

and (II) SBS modified asphalt is used as cementing material, and the optimal asphalt usage amount is 6.3% of the mixture mass.

And (III) lignin fiber is used as a stabilizer and accounts for 0.3 percent of the mass of the mixture.

And the designed porosity of the mixture is 4.0 percent, and the synthetic grading curve is shown in the attached figure 1. The specific passage rate of the synthetic grading is shown in the following table:

(V) paving step

S1, traffic sealing is carried out according to an actual road surface section needing to be treated, then milling is carried out, fine milling is adopted for milling, milling thickness is strictly controlled to be 15-20 mm, and the situation that an original surface layer is milled, remained and thinned to form a thin interlayer is avoided;

s2, carefully cleaning a milled surface after milling, drying, cleaning and avoiding impurities, and informing a backyard of mixing a mixture in the field cleaning process;

s3, the mixing process of the fine-grain type thin-layer overlay asphalt mixture is similar to that of the traditional SMA mixture, and the following steps are followed: weighing aggregate → putting fiber → metering asphalt → mixing mixture → loading mixture, controlling the heating temperature of aggregate at 210 ℃ and the heating temperature of asphalt at 170 ℃, and considering that the temperature loss is fast during the construction of thin-layer mixture, the discharging temperature of the mixture is preferably controlled at 180-185 ℃;

s4, after the on-site milling and planing surface is cleaned, after the inspection and acceptance are qualified, spreading a hot asphalt seal coat, wherein a synchronous chip seal coat spreading vehicle is adopted, and the hot asphalt isThe SBS modified asphalt is preferably sprayed at 1.0-1.2 Kg/m²The crushed stone is 4.75-9.5 mm crushed stone which is pre-mixed by adding 0.3% petroleum asphalt in the dust removal of the mixing station, the pre-mixed crushed stone is preferably in a whitish state, and the spreading amount of the crushed stone is preferably 5.5-6.0 Kg/m²The light rubber wheel is used for stabilizing the pressure for 2 times;

and S5, after the hot asphalt macadam seal coat is finished, the paver is in place to preheat for at least 1h, the temperature of an ironing plate is not lower than 100 ℃, mixed material paving is carried out, the speed during paving is strictly controlled to be 3.5 +/-0.2 m/min, the paving speed is kept uniform, the rolling after the mixed material paving follows the principle of 'following, slow pressing, high frequency, low amplitude and little water', and a fine grain type thin-layer cover coat with the thickness of 25mm is formed after compaction.

And (VI) testing the obtained finish coat according to national and industrial standards, wherein the compaction void ratio is 4.5-5.5%, the dynamic stability rut proved by experience is 4238 times/mm, the deepwater coefficient is 20ml/min, the structure depth is 0.84mm, and the pendulum friction value is 68 BNP.

Example two:

firstly, diabase macadam with the thickness of 3-8 mm and 3-5 mm is used as a coarse aggregate, diabase machine-made sand with the thickness of 0-3mm is used as a fine aggregate, and limestone mineral powder is used as a filler.

The weight ratio of each level of mineral aggregate is as follows:

and (II) taking high-viscosity high-elasticity modified asphalt as a cementing material. The optimal asphalt dosage is 6.2 percent of the mass of the mixture.

And (III) lignin fiber is used as a stabilizer and accounts for 0.3 percent of the mass of the mixture.

And the designed porosity of the mixture is 4.0 percent, and the synthetic grading curve is shown in the attached figure 2. The specific passage rate of the synthetic grading is shown in the following table:

and (V) paving: following compaction, a fine-grained, thin-film overcoat having a thickness of 20mm was formed as in example one.

And (VI) testing the obtained finish coat according to national and industrial standards, wherein the compaction void ratio is 4.3-5.2%, the dynamic stability rut proved by experience is 4369 times/mm, the deepwater coefficient is 15ml/min, the construction depth is 0.92mm, and the pendulum friction value is 72 BNP.

The detection data show that the volume index of the compacted core sample completely meets the control requirement of site construction, the high-temperature performance of the mixture can also meet the relevant requirement, the surface of the fine grain type thin layer cover surface is compact after construction, and the anti-slip performance is excellent after anti-slip index detection.

The present invention has been described in detail with reference to specific embodiments, which are intended to be illustrative only and not limiting. Insubstantial modifications of the invention, made by those skilled in the art based on the teachings of the invention, fall within the scope of the invention.