Composite pavement anti-rutting surface layer structure and road construction

Abstract

The utility model discloses a composite road surface anti -rut surface layer structure, including by the setting from below to above asphalt lower surface layer and asphalt upper surface layer, asphalt lower surface layer is the skeleton half -space asphalt mixture lower surface layer, and asphalt upper surface layer is the skeleton dense asphalt mixture upper surface layer. The utility model discloses still a kind of road structure, including composite road surface anti -rut surface layer structure, and the cement concrete base layer is equipped in the bottom of the skeleton half -space asphalt mixture lower surface layer. The utility model improves the performance of composite road surface, prolongs its service life, and can be widely applied in road design and construction field.

Description

Technical Field

[0001] This utility model relates to the design and construction of highways and urban roads, and in particular to a composite pavement anti-rutting surface layer structure and road construction. Background Technology

[0002] Composite pavement refers to a pavement whose surface layer is composed of two structural layers with different material types and mechanical properties. Commonly used structures include composites of ordinary concrete, roller-compacted concrete, lean concrete, or continuously reinforced concrete with asphalt concrete surface layers. The cement concrete slab, acting as a rigid base layer, enhances the load-bearing capacity of the asphalt pavement, meeting the requirements of heavy loads, overloads, and high traffic volumes. The asphalt concrete surface layer improves and enhances the surface quality of the concrete pavement, meeting the performance requirements of high-speed vehicles and facilitating maintenance. Composite pavement fully meets the durability and comfort requirements of pavement structures under heavy traffic conditions and is one of the main structural forms of long-life pavements under current environmental conditions in my country.

[0003] Composite pavements combine rigidity and flexibility, but rutting is one of their typical defects. Since concrete slabs do not undergo permanent deformation, rutting in composite pavements is mainly caused by the permanent deformation of the asphalt surface layer. Typically, composite pavement asphalt surface layers employ a two-layer suspended dense structure, such as 4cm thick AC-13C asphalt concrete + 6cm thick AC-20C asphalt concrete, or 4cm thick AC-13C asphalt concrete + 5cm thick AC-16C asphalt concrete. The structural strength of suspended dense asphalt mixtures relies primarily on the bond strength between asphalt and aggregates and the cohesive force of the asphalt. The internal friction between aggregate particles is relatively low. Under heavy loads, high temperatures, and low-speed traffic conditions, composite pavements are highly susceptible to rutting. Therefore, the project used a skeleton-dense asphalt mixture, such as SMA (stable aggregate mastic asphalt), as the asphalt surface layer to improve rutting resistance. However, due to cost constraints, two layers of SMA could not be used, and the lower layer continued to use suspended dense AC asphalt concrete. Since rutting mainly occurs in the middle and lower layers, this structure still could not effectively solve rutting problems. To ensure the long-term performance of the composite pavement, an economical and effective integral rutting-resistant structure is needed. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide a composite pavement anti-rutting surface layer structure and road construction, which is based on a double-layer composite anti-rutting surface layer with a dense skeleton structure and a semi-porous skeleton structure, thereby improving the performance of the composite pavement and extending its service life.

[0005] This utility model provides a composite pavement anti-rutting surface layer structure, which includes an asphalt lower layer and an asphalt upper layer arranged from bottom to top. The asphalt lower layer is a skeleton semi-porous asphalt mixture lower layer, and the asphalt upper layer is a skeleton dense asphalt mixture upper layer.

[0006] In the above technical solution, the lower layer of the skeleton semi-porous asphalt mixture is an improved skeleton semi-porous asphalt mixture GAK (improved anti-skid asphalt) lower layer.

[0007] In the above technical solution, the skeleton dense asphalt mixture upper layer is the skeleton dense asphalt mixture SMA upper layer.

[0008] In the above technical solution, the gradation of the improved skeleton semi-porous asphalt mixture GAK is as follows: coarse aggregate accounts for 80%~85%, mineral powder content below 0.075mm is not greater than 5%, asphalt-aggregate ratio is not greater than 4%, and porosity is 6%~8%.

[0009] In the above technical solution, a hot asphalt waterproof bonding layer is provided between the lower layer of the skeleton semi-porous asphalt mixture and the upper layer of the skeleton dense asphalt mixture.

[0010] In the above technical solution, the hot asphalt waterproof bonding layer is a hot asphalt WAC waterproof bonding layer.

[0011] In the above technical solution, the gradation of the hot asphalt WAC waterproof bonding layer is as follows: the SBS modified asphalt application rate is 1.6~2.0 kg / m³. 2 Crushed stone with a surface coverage of 60-70% and a single particle size of 9.5-13.2 mm.

[0012] The present invention also provides a road structure, including a composite pavement anti-rutting surface layer structure, wherein a cement concrete base layer is provided at the bottom of the skeleton semi-porous asphalt mixture lower layer.

[0013] In the above technical solution, the side of the road structure is provided with an impermeable geomembrane whose top extends through the lower layer of the skeleton semi-porous asphalt mixture into the upper layer of the skeleton dense asphalt mixture, and whose bottom extends into the bottom of the cement concrete base and inserts into the adjacent green belt.

[0014] The composite pavement anti-rutting surface layer structure and road construction of this utility model have the following beneficial effects:

[0015] (1) The top layer of the composite pavement uses skeleton dense asphalt mixture SMA, which has excellent anti-skid texture depth and anti-rutting ability. At the same time, it has a small porosity, good water tightness, and strong resistance to water damage. (2) The bottom layer of the composite pavement uses improved skeleton semi-porous asphalt mixture GAK. In its gradation, the proportion of coarse aggregate is more than 80%, the content of mineral powder below 0.075mm is not more than 5%, the asphalt-aggregate ratio is not more than 4%, and the porosity is 6%~8%. The interlocking structure dominated by coarse aggregate does not rely on the adhesion of asphalt and still has a strong anti-rutting ability at high temperature. Together with the skeleton dense asphalt mixture SMA top layer, it forms a double-layer composite anti-rutting surface layer. (3) A hot asphalt WAC waterproof bonding layer is used between the SMA top layer and the GAK bottom layer to strengthen the interlayer bonding. At the same time, it prevents rainwater that seeps into the SMA top layer from entering the GAK bottom layer, thus avoiding adverse effects on the water stability of the GAK. (4) A seepage-proof geomembrane is laid on the edge of the double-layer composite anti-rutting surface layer to prevent water seepage from the green belt on the edge from entering the GAK bottom layer, thus avoiding the formation of a water-stagnant channel in the GAK and improving its durability. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the composite pavement anti-rutting surface layer structure and road construction of this utility model. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but these embodiments should not be construed as limiting the present invention.

[0018] Skeleton-semi-porous asphalt mixtures, such as AK (anti-skid asphalt), were initially used as surface layers in asphalt pavements primarily because their high coarse aggregate content allowed them to interlock and form a skeleton, resulting in good anti-skid texture depth and rutting resistance. However, in engineering applications, it was found that the low content of fine aggregates and mineral powder led to insufficient asphalt content, relatively high porosity, and inadequate adhesion between asphalt and aggregates. Under dynamic water pressure, asphalt easily peeled off the aggregate surface, causing widespread early-stage damage during the rainy season. Therefore, they were gradually replaced by suspension-dense asphalt mixtures (AC) and skeleton-dense asphalt mixtures (SMA). Improving the gradation of skeleton-semi-porous asphalt mixtures and moving them from the surface layer to the lower layers, while simultaneously ensuring interlayer and edge waterproofing, can maximize their advantages and minimize their disadvantages, fully leveraging their low cost and strong rutting resistance.

[0019] See Figure 1The composite pavement anti-rutting surface layer structure and road construction of this utility model are realized by the following structure: an improved skeleton semi-porous asphalt mixture GAK is laid on the cement concrete base layer 1, and then a hot asphalt WAC waterproof bonding layer is implemented as the hot asphalt waterproof bonding layer 3. After that, a skeleton dense asphalt mixture SMA is laid as the skeleton dense asphalt mixture top layer 4. At the same time, an impermeable geomembrane 5 is laid at the edge of the pavement structure.

[0020] The specific construction steps are as follows: After the cement concrete base layer 1 is poured and cured, a modified skeleton semi-porous asphalt mixture GAK-20 is laid on it with a thickness of 6cm. The GAK-20 mixture contains 82% coarse aggregate larger than 2.36mm, 4% mineral powder smaller than 0.075mm, an asphalt-aggregate ratio of 4.0%, and a porosity of 7%. Its Marshall test rutting dynamic stability reaches 6000 cycles / mm, demonstrating significant rutting resistance. Hot asphalt WAC is simultaneously laid on top of the modified skeleton semi-porous asphalt mixture GAK-20 as a waterproof bonding layer 3. The WAC hot asphalt uses SBS modified asphalt, with a spraying rate of 1.6~2.0 kg / m³. 2 After applying hot asphalt, 9.5-13.2mm single-size crushed stone is immediately spread, with a surface coverage rate of 60-70%. After the hot asphalt WAC waterproof bonding layer is laid, a 4cm thick dense asphalt mixture SMA-13 ​​is laid. After completing the composite pavement double-layer anti-rutting surface layer, an impermeable geomembrane 5 is laid along its edges. The impermeable geomembrane 5 extends from the center of the dense asphalt mixture SMA-13 ​​to the bottom of the cement concrete base layer 1, and then extends into the side green belt (not shown in the figure) fill. These steps complete the composite pavement anti-rutting surface layer structure and road construction of this utility model.

[0021] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

[0022] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A composite pavement anti-rutting surface layer structure, comprising an asphalt lower layer and an asphalt upper layer arranged from bottom to top, characterized in that: The lower asphalt layer is a skeleton semi-porous asphalt mixture lower layer (2), and the upper asphalt layer is a skeleton dense asphalt mixture upper layer (4); the lower asphalt mixture lower layer (2) is an improved skeleton semi-porous asphalt mixture GAK lower layer; the upper asphalt mixture upper layer (4) is a skeleton dense asphalt mixture SMA upper layer.

2. The composite pavement anti-rutting surface layer structure according to claim 1, characterized in that: A hot asphalt waterproof bonding layer (3) is provided between the lower layer (2) of the skeleton semi-void asphalt mixture and the upper layer (4) of the skeleton dense asphalt mixture.

3. The composite pavement anti-rutting surface layer structure according to claim 2, characterized in that: The hot asphalt waterproof bonding layer (3) is a hot asphalt WAC waterproof bonding layer.

4. The composite pavement anti-rutting surface layer structure according to claim 3, characterized in that: The gradation of the hot asphalt WAC waterproof bonding layer is as follows: SBS modified asphalt application rate is 1.6~2.0 kg / m³. 2 Crushed stone with a surface coverage of 60-70% and a single particle size of 9.5-13.2 mm.

5. A road structure comprising a composite pavement anti-rutting surface layer structure as described in any one of claims 1 to 4, characterized in that: The bottom of the skeleton semi-void asphalt mixture lower layer (2) is provided with a cement concrete base layer (1).

6. The road structure according to claim 5, characterized in that: The road structure has a geomembrane (5) on its side, which extends from the bottom layer (2) of the semi-void asphalt mixture to the top layer (4) of the dense asphalt mixture and extends to the bottom of the cement concrete base layer (1) and into the adjacent green belt.

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