CN111926648A

CN111926648A - Asphalt concrete road pavement structure

Info

Publication number: CN111926648A
Application number: CN202010842433.7A
Authority: CN
Inventors: 胡剑安
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-08-20
Filing date: 2020-08-20
Publication date: 2020-11-13

Abstract

The invention relates to the technical field of pavement construction, and discloses a bituminous concrete road pavement structure. Comprises a soil layer, a base layer laid above the soil layer, a cement concrete layer laid above the base layer and an asphalt layer laid above the concrete layer; the cement concrete layer is horizontally provided with a reinforcing steel bar inner net layer inside, and the asphalt layer comprises an asphalt bottom layer and an asphalt surface layer paved above the asphalt bottom layer. The asphalt concrete road pavement structure has excellent anti-cracking performance and water damage resistance, thereby prolonging the service life of the road pavement.

Description

Asphalt concrete road pavement structure

Technical Field

The invention relates to the technical field of pavement construction, in particular to a bituminous concrete road pavement structure.

Background

The highway is one of basic facilities for interconnection between cities, and directly restricts the development of urban economy, so that the highway is ensured to be in a good operation state, and the highway has very important significance for the construction and development of the cities. With the rapid development of national economy and the increase of material flow in China, the road traffic volume in China is increasing day by day, and the axle weight of a vehicle is developing to large tonnage. The pavement material is gradually developed from the original earth-rock pavement to the current concrete pavement, wherein the asphalt concrete pavement not only has more comfortable driving feeling, but also has short construction period and simple and quick maintenance and repair, thereby becoming the most widely used pavement. With the increasing traffic volume and the further improvement of the driving demand of pedestrians on the road surface, higher requirements are also put forward on the road performance of the road surface. The improvement of asphalt concrete pavement is a problem of continuous research of scholars in road engineering industry. The common road pavement is mainly a single asphalt pavement or a cement pavement, but the single asphalt pavement has the problems of low strength and weak bearing capacity, and the bearing capacity of the pavement can be obviously improved by combining the asphalt pavement and the cement pavement. However, the asphalt pavement and the cement pavement are still prone to cracking after being combined, and the asphalt pavement and the cement pavement are affected by the driving pressure of the pavement and the temperature change of the natural environment, so that cracking of different degrees can be generated. Pavement cracking is one of the main forms of pavement damage, and how to improve the cracking resistance of asphalt concrete is always the key to improving the pavement performance. On the other hand, the asphalt matrix in the asphalt pavement is easily eroded by rainwater, so that the durability of the pavement is reduced, and the service life of the asphalt mixture is influenced.

For example, chinese patent publication No. CN204825549 discloses a rock asphalt road structure, which includes a base layer and a lining layer laid on the base layer, a cement concrete base layer is laid on the lining layer, flat drainage stones are arranged on two sides of the cement concrete base layer, the upper portion of the cement concrete base layer is in a tooth-like arrangement, an asphalt pavement layer is laid on the cement concrete base layer, the asphalt pavement layer includes a coarse asphalt bottom layer and an asphalt surface layer, the obtained asphalt pavement has strong bearing capacity, high flatness and good drainage effect, but the pavement is affected by road driving pressure and natural environment temperature change, and cracks in different degrees can be generated, and the asphalt matrix in the asphalt pavement is easily eroded by rainwater, so that the durability of the pavement is reduced, and the service life of the asphalt mixture is affected.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provides a bituminous concrete road pavement structure. The asphalt concrete road pavement structure has excellent anti-cracking performance and water damage resistance, thereby prolonging the service life of the road pavement.

In order to achieve the purpose, the invention adopts the following technical scheme: an asphalt concrete road pavement structure comprises a soil layer, a base layer paved above the soil layer, a cement concrete layer paved above the base layer and an asphalt layer paved above the concrete layer; the cement concrete layer is horizontally provided with a reinforcing steel bar inner net layer inside, and the asphalt layer comprises an asphalt bottom layer and an asphalt surface layer paved above the asphalt bottom layer.

According to the invention, the base layer is laid above the soil layer, the cement concrete layer is laid above the base layer, the asphalt layer is laid above the cement concrete layer, and the concrete layer and the asphalt layer are combined, so that the bearing capacity of the road pavement can be obviously improved; through set up the reinforcing bar stratum reticulare through the level in cement concrete layer inside, the reinforcing bar stratum reticulare can play the skeleton reinforcing effect to cement concrete layer to improve

The crack resistance of the cement concrete layer.

Preferably, a reinforcing steel bar outer net layer is laid on the surface of the cement concrete layer, and the reinforcing steel bar outer net layer is embedded in the cement concrete layer and protrudes relative to the upper surface of the cement concrete layer.

According to the invention, the reinforcing steel bar outer net layer is laid on the surface of the cement concrete layer, the reinforcing steel bar outer net layer is embedded into the cement concrete layer and presents a protruding structure relative to the upper surface of the cement concrete layer, and the protruding structure of the reinforcing steel bar outer net layer is embedded into the asphalt bottom layer, so that the effect of connecting the asphalt layer and the cement concrete layer is achieved, the bonding acting force of the asphalt layer and the cement concrete layer is enhanced, and the separation phenomenon caused by the influence of the natural environment on the asphalt layer and the cement concrete layer for a long time.

Preferably, the base layer is a broken brick, a broken tile, a broken stone or a broken porcelain.

Preferably, the asphalt surface layer material is formed by mixing rock asphalt and basalt fiber asphalt mixture.

Preferably, the asphalt base layer material is a basalt fiber asphalt mixture.

Preferably, the preparation method of the basalt fiber asphalt mixture comprises the following steps:

1) the SBS modified asphalt is placed in an oven and heated to be molten at the temperature of 160-170 ℃ to obtain molten SBS modified asphalt; 2) respectively adding the aggregate and the mineral powder into a drying oven, and heating and drying at the temperature of 170-175 ℃ to constant weight;

3) adding the aggregate and the modified basalt fiber into a stirring device preheated to 165-175 ℃ for stirring for 30-50s, adding the molten SBS modified asphalt into the stirring device, continuing stirring for 1-3min, then adding the mineral powder, and stirring for 80-90s to obtain the modified basalt fiber reinforced cement.

Preferably, the preparation method of the SBS modified asphalt in the step 1) comprises the following steps: heating the matrix asphalt to 140-.

According to the invention, sodium alginate is added in the preparation process of the SBS modified asphalt, the sodium alginate is a natural polysaccharide extracted from brown algae plants, the environment is protected, no pollution is caused to the environment, the sodium alginate is a high-viscosity polymer compound, the viscosity of the SBS modified asphalt can be obviously improved when the sodium alginate is mixed into the SBS modified asphalt, the adhesion performance between the SBS modified asphalt and aggregate or basalt fiber is favorably improved, the phenomenon that water molecules penetrate into the asphalt mixture to cause the stripping phenomenon between the SBS modified asphalt and the aggregate or basalt fiber is avoided, and the waterproof performance of the asphalt mixture is improved.

Preferably, the aggregate in the step 2) comprises the following two groups according to particle size: the first group of aggregates is 6-12 mm; the second group of aggregates is 2-5 mm; the mass ratio of the first group of aggregates to the second group of aggregates is 1: 0.2-0.6.

Preferably, the mineral powder in the step 2) is limestone; the particle size of the limestone is less than or equal to 0.075 mm.

Preferably, the preparation method of the modified basalt fiber in the step 3) comprises the following steps;

adding butyl titanate into absolute ethyl alcohol, and uniformly stirring to obtain a solution A for later use; adding glacial acetic acid and deionized water into absolute ethyl alcohol, and uniformly stirring to obtain a solution B for later use; adding dopamine hydrochloride into deionized water, stirring and dissolving, dropwise adding a Tirs-HCl buffer solution and a sodium hydroxide solution to adjust the pH value of a system to 8-9 to obtain a dopamine solution, adding basalt fibers into the dopamine solution, stirring and reacting for 2-5 hours, adding a solution B into a reaction solution after the reaction is finished, stirring and mixing uniformly to obtain a mixed solution, dropwise adding a hydrochloric acid solution to adjust the pH value to 2-3, heating in a water bath to 50-55 ℃, then dropwise adding a solution A into the mixed solution, stirring and reacting for 3-6 hours, standing for 10-15 hours after the reaction is finished, filtering and separating, and placing in an oven for drying treatment to obtain the modified basalt fibers.

According to the invention, the basalt fiber is added into the SBS modified asphalt to improve the strength and the anti-cracking performance of the asphalt mixture, and the reinforcing performance of the basalt fiber to the SBS modified asphalt is weakened because the bonding performance between the SBS modified asphalt and the basalt fiber is poor and the SBS modified asphalt and the basalt fiber are easily corroded by rainwater to cause the stripping phenomenon of the SBS modified asphalt and the basalt fiber. On the other hand, on the one hand, the viscosity of the SBS modified asphalt is improved by adding the high-viscosity sodium alginate in the preparation process of the SBS modified asphalt, so that the adhesive property between the SBS modified asphalt and the basalt fiber is improved; on the other hand, the basalt fiber is modified, n-butyl titanate is used as a precursor, nano titanium dioxide colloid is prepared through hydrolytic deposition, nano titanium dioxide colloid particles are deposited and combined on the surface of the basalt fiber, so that the surface of the basalt fiber presents a granular protruding structure, the roughness of the surface of the basalt fiber is improved, an anchoring effect is formed between SBS modified asphalt and the protruding structure of the surface of the basalt fiber, and the bonding strength between the basalt fiber and the SBS modified asphalt is enhanced. However, in the step of preparing and mixing the mixture, under the action of stirring disturbance of materials, the nano titanium dioxide colloid combined on the surface of the basalt fiber is easy to separate from the surface of the basalt fiber, so that the roughness of the surface of the basalt fiber is reduced. In addition, the autoxidation polymerization coating of the polydopamine organic layer on the surface of the basalt fiber can improve the compatibility of the basalt fiber in the asphalt, further improve the bonding strength between the SBS modified asphalt and the basalt fiber, and further improve the reinforcing effect of the basalt fiber on the SBS modified asphalt.

Drawings

Fig. 1 is a schematic structural view of the asphalt concrete road pavement structure of the present invention.

Fig. 2 is a schematic view of the enlarged structure of a portion a in fig. 1 according to the present invention.

FIG. 3 is a schematic view of the structure of the asphalt layer of the present invention.

Detailed Description

The technical solution of the present invention is further illustrated by the following specific examples. In the present invention, unless otherwise specified, raw materials, equipment, and the like used are commercially available or commonly used in the art, and the methods in the examples are conventional in the art unless otherwise specified.

The matrix asphalt used in the specific embodiment is China petrochemical Jinling petrochemical No. 70, and the main technical parameter indexes are as follows:

sodium alginate used in the specific examples: 100 plus 200mPa.s, the water content is less than or equal to 15.0 percent, the water insoluble substance is less than or equal to 0.6 percent, the viscosity reduction rate is less than or equal to 20 percent, and the product is produced by Shaanxi Chengming Biotechnology Co.

The aggregates used in the specific examples are divided into two groups according to particle size, the first group of aggregates having a particle size of 6-12 mm; the second group of aggregate has the grain diameter of 2-5 mm; the granularity of the mineral powder is less than or equal to 0.075 mm.

Example 1

As shown in fig. 1, the asphalt concrete road pavement structure of the present invention includes a soil layer 1, a base layer 2 laid on the soil layer, a cement concrete layer 3 laid on the base layer, and an asphalt layer 4 laid on the concrete layer, wherein the base layer is broken bricks, broken tiles, broken stones, or broken porcelain blocks; fig. 3 is a schematic structural diagram of an asphalt layer according to the present invention, which includes an asphalt base layer 41 and an asphalt surface layer 42 laid on the asphalt base layer; fig. 2 is a partial enlarged structural schematic diagram of the invention at a in fig. 1, a reinforced inner mesh layer 5 is horizontally arranged inside the cement concrete layer, a reinforced outer mesh layer 6 is laid on the surface of the cement concrete layer, the reinforced outer mesh layer is embedded in the cement concrete layer and is raised relative to the upper surface of the cement concrete layer, and the raised part of the reinforced outer mesh layer relative to the upper surface of the cement concrete layer is embedded inside an asphalt bottom layer 41.

The asphalt surface layer material is formed by mixing rock asphalt and basalt fiber asphalt mixture; the preparation method of the basalt fiber asphalt mixture comprises the following steps:

1) heating the matrix asphalt to 145 ℃, adding styrene-butadiene-styrene block copolymer and sodium alginate into the matrix asphalt, wherein the addition amount of the styrene-butadiene-styrene block copolymer is 3.5 wt% of the matrix asphalt, the addition amount of the sodium alginate is 1.0 wt% of the matrix asphalt, continuously heating to 175 ℃, uniformly stirring and mixing at 200r/min, then shearing at a high speed of 4000r/min for 60min, cooling to 155 ℃ after shearing is completed, and stirring and developing at a rotating speed of 600r/min for 1h to obtain SBS modified asphalt;

putting the SBS modified asphalt into an oven, heating the oven at 170 ℃ to be molten to obtain molten SBS modified asphalt;

2) respectively adding the aggregate and the mineral powder into an oven, and heating and drying at 170 ℃ until the weight is constant;

the aggregate comprises the following two groups according to the particle size: the first group of aggregates is 6-12 mm; the second group of aggregates is 2-5 mm; the mass ratio of the first group of aggregates to the second group of aggregates is 1: 0.2;

3) adding the aggregate and the modified basalt fiber into a stirring device preheated to 175 ℃ for stirring for 30s, adding molten SBS modified asphalt into the stirring device, continuing stirring for 2min, then adding mineral powder, and stirring for 85 s;

the preparation method of the modified basalt fiber comprises the following steps;

adding butyl titanate into absolute ethyl alcohol according to the volume ratio of 1:20, and uniformly stirring to obtain a solution A for later use; adding glacial acetic acid and deionized water into absolute ethyl alcohol, and uniformly stirring, wherein the volume ratio of the glacial acetic acid to the deionized water to the absolute ethyl alcohol is 1:3:8, so as to obtain a solution B for later use; adding dopamine hydrochloride into deionized water, stirring and dissolving, dropwise adding Tirs-HCl buffer solution and sodium hydroxide solution to adjust the pH of the system to 9 to obtain dopamine solution with the mass concentration of 3.0%, adding basalt fibers into the dopamine solution according to the mass-volume ratio of 1g/50mL, stirring for reaction for 4h, adding the solution B into the reaction solution after the reaction is finished, wherein the volume ratio of the dopamine solution to the solution B is 1:2, stirring and mixing uniformly to obtain a mixed solution, dropwise adding a hydrochloric acid solution with the concentration of 0.5mol/L to adjust the pH value to 2, heating in a water bath to 55 ℃, and then dropwise adding the solution A into the mixed solution, wherein the mass ratio of the basalt fiber to the butyl titanate is 1:0.4, stirring for reaction for 5 hours, standing for 13 hours after the reaction is finished, filtering and separating, and drying in an oven at 80 ℃ for 2 hours to obtain the modified basalt fiber.

In the preparation process of the basalt fiber asphalt mixture, the material adding proportion is as follows according to parts by weight: 4.5 parts of SBS modified asphalt, 0.45 part of modified basalt fiber, 91 parts of basalt aggregate and 3 parts of limestone mineral powder.

Firstly, testing the water resistance of the asphalt mixture:

immersion marshall test: placing test pieces (the specification of the test pieces is that the diameter is 101.6 +/-0.25 mm, the height is 63.5 +/-0.25 mm) in a constant-temperature water tank with the temperature reached for heat preservation for 35min, keeping intervals among the test pieces, padding the bottom of the test pieces and keeping the distance from the bottom to be not less than 5cm, placing an upper pressure head and a lower pressure head of a Marshall tester in the water tank to reach the same temperature, taking the upper pressure head and the lower pressure head out of the water tank, wiping the inner surfaces of the upper pressure head and the lower pressure head clean, coating a small amount of butter on a guide rod of the lower pressure head in order to enable the upper pressure head and the lower pressure head to slide freely, taking the test pieces out, placing the test pieces on the lower pressure head, covering the upper pressure head, then installing the test pieces on a loading device, starting the loading device to. The residual stability of the test piece in the water immersion Marshall test is calculated according to the following formula:

MS₀＝MS₁(ii)/MS × 100%; wherein, MS₀Indicates the immersion residual stability,%; MS (Mass Spectrometry)₁Shows the stability, KN, of the test piece after being soaked in water for 48 hours; MS indicates the stability, KN, of the test piece.

Secondly, testing the interfacial adhesion of the basalt fiber and the asphalt cement:

adopting a fiber asphalt drawing tester to test the binding power of basalt fibers and asphalt cement, preparing the asphalt cement according to the mixture ratio, heating the asphalt cement material to 150 ℃ to be in a flowing state, then beginning to pour a sample, pouring half of the asphalt material into a test mold, slowly penetrating the basalt fibers used in the embodiment and the comparative example into gaps at two ends of the test mold, slightly placing the basalt fibers on the upper surface of the asphalt material to keep horizontal, applying fine tension at two ends to straighten the fibers, then slowly pouring the other half of the asphalt material from one end to the other end of the test mold to enable the sample to slightly exceed the sample, standing the sample, cooling to room temperature, scraping the asphalt material with a hot scraper to enable the surface to protrude, respectively embedding and externally arranging the basalt fibers, cutting off the fibers at the non-stretching end at the edge of the test sample, placing the test sample to be tested on a fixed pile to be fixed in a test environment bin, adjusting the position of the clamp through a control panel to enable the clamping end of the clamp to return to a zero position, and then enabling the basalt fiber at the free section at one end of the sample to pass through a small hole of a loading device and be connected with the clamp; covering an organic glass cover, switching on a power supply to start the testing machine, opening a temperature controller until the device is kept at a test temperature for 1h at a constant temperature, starting a drawing test, enabling a clamp connected with basalt fibers to move rightwards along with the drawing testing machine at a constant speed of 10mm/min, applying a tensile force to the basalt fibers until the basalt fibers are completely drawn out, stopping the test, reading a tensile force and a corresponding displacement data change value output by a data acquisition system, and recording the maximum load (N) of the basalt fibers. The larger the maximum load of the basalt fiber is, the better the binding property of the basalt fiber and the asphalt is proved.

The combination obtained by the tests can obtain that the stability of the asphalt mixture is reduced slightly after the asphalt mixture is soaked for 48 hours, and the residual stability of the asphalt mixture reaches 93.7 percent, so that the asphalt provided by the invention has excellent water damage resistance. The maximum load of the basalt fiber can reach more than 0.256N in single basalt fiber with the fiber burial depth of 6mm, 12mm and 20mm, and the basalt fiber and the asphalt are proved to have excellent bonding performance.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The asphalt concrete road pavement paving structure is characterized by comprising a soil layer (1), a base layer (2) paved above the soil layer, a cement concrete layer (3) paved above the base layer and an asphalt layer (4) paved above the concrete layer; the concrete layer is internally and horizontally provided with a steel bar inner net layer (5), and the asphalt layer comprises an asphalt bottom layer (41) and an asphalt surface layer (42) paved above the asphalt bottom layer.

2. An asphalt concrete road pavement structure according to claim 1, wherein the surface of the cement concrete layer is paved with a reinforcing steel bar outer net layer (6), and the reinforcing steel bar outer net layer is embedded in the cement concrete layer and is raised relative to the upper surface of the cement concrete layer.

3. The asphalt concrete road pavement structure according to claim 1, wherein the base layer is broken bricks, broken tiles, broken stones or broken porcelain blocks.

4. The asphalt concrete road pavement structure according to claim 1, wherein the asphalt surface layer material is formed by mixing rock asphalt and basalt fiber asphalt mixture.

5. The asphalt concrete road pavement structure according to claim 1, wherein the asphalt base layer material is basalt fiber asphalt mixture.

6. The asphalt concrete road pavement structure according to claim 4 or 5, wherein the preparation method of the basalt fiber asphalt mixture comprises the following steps:

1) the SBS modified asphalt is placed in an oven and heated to be molten at the temperature of 160-170 ℃ to obtain molten SBS modified asphalt;

2) respectively adding the aggregate and the mineral powder into a drying oven, and heating and drying at the temperature of 170-175 ℃ to constant weight;

7. The asphalt concrete road pavement structure according to claim 6, wherein the preparation method of SBS modified asphalt in the step 1) comprises the following steps: heating the matrix asphalt to 140-.

8. The asphalt concrete road pavement structure according to claim 6, wherein the aggregates in the step 2) comprise the following two groups according to particle size: the first group of aggregates is 6-12 mm; the second group of aggregates is 2-5 mm; the mass ratio of the first group of aggregates to the second group of aggregates is 1: 0.2-0.6.

9. The bituminous concrete road pavement structure according to claim 6, wherein the mineral powder in step 2) is limestone; the particle size of the limestone is less than or equal to 0.075 mm.

10. The asphalt concrete road pavement structure according to claim 6, wherein the preparation method of the modified basalt fiber in the step 3) comprises the following steps;