CN110846968B

CN110846968B - Permeable asphalt pavement structure

Info

Publication number: CN110846968B
Application number: CN201911155862.0A
Authority: CN
Inventors: 王林; 李嵩; 赵玉静; 刘帅; 林龙杰
Original assignee: Shanghai Baotian New Building Materials Co Ltd; Shanghai Baosteel Energy Service Co Ltd
Current assignee: Shanghai Baotian New Building Materials Co Ltd; Shanghai Baosteel Energy Service Co Ltd
Priority date: 2019-11-22
Filing date: 2019-11-22
Publication date: 2021-07-20
Anticipated expiration: 2039-11-22
Also published as: CN110846968A

Abstract

The invention provides a permeable asphalt pavement structure which sequentially comprises an asphalt mixture surface layer, a permeable base layer, a sealing layer, a non-permeable subbase layer and a roadbed from top to bottom, wherein a water collecting ditch is arranged at the outer side edge of the bottom of the non-permeable subbase layer, a water guide pipe is arranged at the bottom of the water collecting ditch, and steel slag crushed stones are filled in the water collecting ditch; the mixing amount of the steel slag aggregate in the asphalt mixture surface layer is 30-90%, the mixing amount of the steel slag aggregate in the permeable base layer is 50-70%, the mixing amount of the steel slag aggregate in the non-permeable base layer is 40-90%, and the mixing amount of the steel slag in the water collecting ditch is 50-80%; according to the invention, the roller steel slag is doped in the asphalt mixture surface layer, the permeable base layer, the non-permeable subbase layer and the internal drainage system of the pavement, so that the recycling of the steel slag is realized, the bearing capacity of the permeable asphalt pavement is improved, pavement diseases are reduced, the service durability of the pavement is improved, and phosphorus-containing and nitrogen-containing pollutants in rainwater are effectively reduced, thereby being beneficial to reducing water resource pollution.

Description

Permeable asphalt pavement structure

Technical Field

The invention belongs to the technical field of permeable asphalt pavements, and particularly relates to a permeable asphalt pavement structure capable of comprehensively utilizing steel slag solid waste.

Background

The permeable asphalt pavement can reduce the phenomena of rainwater runoff and urban waterlogging on the pavement and is also beneficial to improving the traffic safety of the road. The permeable asphalt pavement has large gaps, and is often damaged by structures such as loosening, pits and the like under the load action. Practice has found that conventional water-permeable asphalt pavements lack good durability in use. Meanwhile, with the enhancement of environmental awareness, the mountaineering and quarrying in many areas are restricted by policies. In order to improve the mechanical strength of the permeable asphalt pavement and increase the bearing capacity and durability of the permeable asphalt pavement, it is necessary to search for alternative resources and design the permeable asphalt pavement with high strength and good durability.

The steel slag is a solid waste product of a steel-making enterprise and has huge yield. The steel slag is generally stacked and treated, the comprehensive utilization rate is low, a large amount of land resources are occupied, and pollution is caused to air, water, environment and the like. On one hand, the steel slag has high mechanical property, good particle shape, strong wear resistance, developed surface micropores, excellent adhesion with asphalt and lower price, and is a better road building aggregate. The steel slag has application cases in roadbeds as a road building material, but is less applied to pavement surface layers, particularly permeable pavements. The main reason is that the steel slag produced by the prior iron and steel enterprises has too high content of free calcium oxide, which is easy to cause pavement cracking damage. At present, the advanced roller method is adopted by the existing enterprises to produce the steel slag. The roller slag has small content of free calcium oxide, stable property and wide application prospect in permeable asphalt and other pavements.

On the other hand, as the road traffic is more and more complicated, the phosphorus and nitrogen-containing pollutants in the road runoff and the permeated rainwater are increased, but the prior treatment measures for the road rainwater are not more. The steel slag has similar mineral properties with clay mineral, has more surface micropores, has better ion exchange effect, and can remove pollutants such as phosphorus, nitrogen and the like in rainwater.

Disclosure of Invention

The invention provides a permeable asphalt pavement structure, aiming at the problems of low bearing strength, poor durability and the like of the conventional permeable pavement in the prior art.

In order to achieve the above purpose, the solution of the invention is as follows:

the utility model provides a bituminous paving structure permeates water, its from the top down includes bituminous mixture surface course, the basic unit that permeates water, seal, non-permeable subbase and road bed in proper order, and the bottom outside edge of non-permeable subbase is equipped with the catch basin, and the catch basin bottom is equipped with the aqueduct to pack the slag rubble in the catch basin.

Wherein the mixing amount of the steel slag aggregate in the surface layer of the asphalt mixture is 30-90%.

The mixing amount of the steel slag aggregate in the permeable base layer is 50-70%.

The mixing amount of the steel slag aggregate in the non-permeable subbase layer is 40-90%.

The mixing amount of the steel slag in the water collecting channel is 50-80%.

Furthermore, the steel slag in the permeable asphalt pavement structure is roller slag, the content of free calcium oxide in the steel slag is less than 2%, the pulverization rate is less than 2%, and the crushing value is less than 20%.

Further, the asphalt mixture surface layer also comprises stone and an organic binder, and the organic binder is high-viscosity modified asphalt; the water-soaking expansion rate of the asphalt mixture surface layer is less than 2%.

Furthermore, the asphalt mixture surface layer comprises an asphalt mixture upper surface layer and an asphalt mixture lower surface layer, and the thickness of the asphalt mixture surface layer is 11-13 cm.

Furthermore, the upper layer of the asphalt mixture adopts the asphalt mixture with the nominal grain diameter of 9.5-13.2mm, the void ratio is 18-25%, and the thickness is 4-5 cm; the lower layer of the asphalt mixture adopts the asphalt mixture with medium particle size or large particle size, the void ratio is 18-25%, the thickness is 7-8cm, the nominal maximum particle size of the medium particle size is 13.2-19mm, and the nominal maximum particle size of the large particle size is 19-26.5 mm.

Furthermore, the paving thickness of the permeable base layer is 20-60cm, the void ratio is 15-25%, and the 7d compressive strength is not less than 3.5 Mpa; the permeable base layer also comprises an inorganic binder, the mixing amount is 5-40%, and the balance is broken stone; the inorganic binder is selected from more than one of slag, lime, fly ash and cement.

Further, the thickness of the seal layer is 0.5-1.0 cm.

Furthermore, the paving thickness of the non-permeable subbase layer is 15-30cm, and the 7d compressive strength is not less than 2.0 Mpa; the non-permeable subbase layer also comprises inorganic binder with the mixing amount of 5-30 percent and the balance of broken stone; the inorganic binder is selected from more than one of slag, lime, fly ash and cement.

Further, the diameter of the water guide pipe is 70-150 mm; the tube bottom of the water guide tube is flush with the bottom surface of the non-permeable subbase layer; the width of the water collecting channel is 35-60cm, the longitudinal gradient of the water collecting channel is the same as that of the aqueduct and is not less than 0.25%, slag and crushed stone are filled in the water collecting channel, the mixing amount of the slag and the crushed stone is 20-50%, and the crushed stone comprises zeolite and/or vermiculite; the filling height of the water collecting ditch is flush with the top surface of the permeable base layer, and the upper surface of the water collecting ditch is covered with the reverse filtering fabric; and spraying emulsified asphalt around and at the bottom of the water collecting ditch.

Further, the roadbed is compacted, and the degree of compaction is greater than 93%.

Due to the adoption of the scheme, the invention has the beneficial effects that:

firstly, the roller steel slag is reasonably mixed in the asphalt mixture surface layer, the permeable base layer, the non-permeable subbase layer and the internal drainage system of the pavement, so that the bearing capacity of the permeable asphalt pavement is improved, pavement diseases are reduced, the durability of the pavement is further improved, and phosphorus-containing and nitrogen-containing pollutants in rainwater are effectively reduced, thereby being beneficial to reducing water resource pollution.

Secondly, the steel slag is introduced into the full section of the pavement structure, so that a large amount of urban steel slag solid waste can be absorbed, the recycling of the steel slag is realized, the use amount of natural stone is reduced, and the environmental pollution caused by industrial solid waste stacking is reduced, so that the environment is protected, and the pavement structure has good social benefit; in addition, the steel slag is added in a large amount, so that the material cost is low, the pavement strength is high, the later disease is less, and the maintenance cost is low, so that the steel slag-reinforced concrete has better economy.

Thirdly, the road surface structure has good water permeability, so that the rainwater infiltration speed is high, the rainwater runoff on the road surface can be rapidly reduced, and the traffic safety of the road in rainy days is improved.

Fourth, the steel slag is doped in the permeable base layer and the non-permeable base layer, the steel slag contains a small amount of free calcium oxide, has certain expansibility (the water immersion expansion rate is less than 2 percent), and can effectively compensate the drying shrinkage effect of inorganic materials such as lime, cement, fly ash and the like, thereby being beneficial to improving the stability of the base layer.

In a word, the steel slag aggregate is reasonably mixed in the permeable asphalt pavement surface layer, the base layer and the pavement internal drainage system, so that the pavement bearing performance can be improved, the recycling of solid waste of the steel slag can be realized, pollutants in rainwater can be reduced, the rainwater runoff pollution of the pavement can be effectively reduced, the water environment is protected, and the concept of sustainable development is met.

Drawings

FIG. 1 is a schematic structural view of a permeable asphalt pavement according to the present invention.

Reference numerals: 1-an upper asphalt mixture layer, 2-a lower asphalt mixture layer, 3-a permeable base layer, 4-a seal layer, 5-a non-permeable subbase layer, 6-a roadbed, 7-a catchwater ditch and 8-a water guide pipe.

Detailed Description

The invention provides a permeable asphalt pavement structure.

The raw materials used in the invention are as follows:

(1) surface course of asphalt mixture:

steel slag: roller slag from Baoshan iron and Steel company, China; the steel slag contains less than 2% of free calcium oxide, less than 2% of pulverization rate and less than 20% of crushing value.

High-viscosity modified asphalt: shanghai city Nirili Special asphalt Co.

(2) Sealing:

matrix asphalt: is No. 70 or No. 90 base asphalt; emulsified asphalt: emulsified asphalt with solid content of 55-65%.

(3) Permeable base layer and impermeable subbase layer:

cement: selecting ordinary portland cement and slag portland cement with strength grade of 32.5 or 42.5; fly ash: selecting 2-3 grade fly ash; lime: selecting 1-3 grade new ash; soil: selecting powdery clay with plasticity index of 10-15 and organic matter content less than 10%.

The steel slag micro powder is a commercial product which meets the GB/T20491 standard, and the slag powder meets the GB/T18046 standard requirement. Other materials are commercially available products.

Specifically, as shown in fig. 1, the permeable asphalt pavement structure of the present invention sequentially includes, from top to bottom, an asphalt mixture surface layer (i.e., a permeable steel slag and asphalt mixture surface layer), a permeable base layer 3 (i.e., an inorganic binder-stabilized steel slag/crushed stone permeable base layer), a seal layer 4, a non-permeable base layer 5 (i.e., an inorganic binder-stabilized steel slag/crushed stone non-permeable base layer), and a roadbed 6, wherein a water collection ditch 7 is provided at an outer edge of a bottom of the non-permeable base layer 5, a water guide pipe 8 is provided at a bottom of the water collection ditch 7, and the crushed steel slag is filled in the water collection ditch 7.

The steel slag contains less than 2% of free calcium oxide, less than 2% of pulverization rate and less than 20% of crushing value.

(surface layer of asphalt mixture)

The mixing amount of the steel slag aggregate in the surface layer of the asphalt mixture can be 30-90%, preferably 40-80%, and the balance of stone and organic binder, wherein the organic binder is high-viscosity modified asphalt. The water-soaking expansion rate of the asphalt mixture surface layer is less than 2%.

The upper surface layer and the lower surface layer of the asphalt mixture surface layer are paved, namely the upper surface layer 1 of the asphalt mixture and the lower surface layer 2 of the asphalt mixture are included, and the thickness of the asphalt mixture surface layer (i.e. paving) is 11-13 cm.

Wherein, the upper layer 1 of the asphalt mixture adopts a steel slag permeable asphalt mixture PAC-13 or PAC-10 with fine grain diameter (nominal grain diameter is 9.5-13.2mm), the void ratio can be 18-25 percent, the preferential 18-20 percent, and the paving thickness is 4-5 cm. The lower layer 2 of the asphalt mixture adopts permeable asphalt mixture PAC-13 or PAC-20 with medium or large particle size, and the void ratio can be 18-25 percent, preferably 20-23 percent; the spreading thickness is 7-8cm, wherein the nominal maximum particle size of the medium particle size is 13.2-19mm, and the nominal maximum particle size of the large particle size is 19-26.5 mm.

(Water permeable base)

The permeable base layer 3 comprises steel slag aggregate, inorganic binder and crushed stone, wherein the mixing amount of the steel slag aggregate can be 50-70%, preferably 60-70%, the mixing amount of the inorganic binder is 5-40%, and the balance is the crushed stone. The paving thickness of the permeable base layer 3 can be 20-60cm, preferably 30-50cm, the void ratio is 15-25%, and the 7d compressive strength is not less than 3.5 Mpa.

The inorganic binder is one or a mixture of more of slag, lime, fly ash and cement. When cement is used as the inorganic binder, ordinary portland cement or portland slag cement having a strength grade of 32.5 or 42.5 can be used in an amount of 5 to 10%, preferably 6 to 8%.

When the inorganic binder is fly ash, 2-3 grade fly ash can be selected, and the mixing amount of the fly ash can be 15-35%, and 20-30% is preferred.

When the inorganic binder is lime, grade 1-3 lime can be selected, and its mixing amount can be 5-12%, preferably 7-9%.

When the inorganic binder is a mixture of cement, fly ash and lime, the mixing amount ratio is cement: fly ash: lime (0-1) and 1 (2-4).

(seal layer)

The sealing layer 4 is a waterproof layer formed by spraying matrix asphalt or emulsified asphalt on the non-permeable subbase layer 5, and the thickness is 0.5-1.0 cm. The base asphalt can adopt No. 50 and No. 70 base asphalt, and the No. 70 asphalt is preferably adopted. The solid content of the emulsified asphalt may be 50 to 65%, preferably 60 to 65%.

(Water impermeable sub-base)

The non-permeable subbase 5 comprises steel slag aggregate, inorganic binder and macadam, wherein the content of the steel slag aggregate can be 40-90%, preferably 50-80%, the content of the inorganic binder is 5-30%, and the content of the macadam is 10-40%. The thickness of the non-permeable subbase layer 5 is 15-30cm, and the 7d compressive strength is not less than 2.0 Mpa.

The inorganic binder is one or a mixture of more of slag, lime, fly ash and cement.

When cement is used as the inorganic binder, ordinary portland cement or portland slag cement having a strength grade of 32.5 can be used in an amount of 5 to 10%, preferably 5 to 6%.

When the inorganic binder is fly ash, 2-3 grade fly ash can be selected, and the mixing amount of the fly ash can be 15-30%, preferably 15-20%.

When the inorganic binder is lime, grade 1-3 lime can be selected, and its mixing amount can be 5-10%, preferably 7-8%.

When the inorganic binder is a mixture of cement, fly ash and lime, the mixing amount ratio is cement: fly ash: lime (0-0.5) and 1 (1-4).

(catch basin)

The outer edge of the bottom of the non-permeable sub-base layer 5 is provided with a water collecting channel 7, the bottom of the water collecting channel 7 is provided with a water guide pipe 8, and the pipe diameter of the water guide pipe 8 can be 70-150mm, preferably 100-120 mm. The tube bottom of the water guide tube 8 is flush with the bottom surface of the non-permeable subbase 5.

The width of the water collecting ditch 7 is 35-60cm, the longitudinal gradient of the water collecting ditch 7 is the same as that of the water guide pipe 8 and is not less than 0.25%, the water collecting ditch 7 is filled with filler consisting of steel slag, slag and broken stone, the porosity of the filler is greater than that of the permeable base layer 3, wherein the mixing amount of the steel slag can be 50-80%, and preferably 60-80%. The amount of slag and crushed stone (zeolite and/or vermiculite) blended may be 20-50%, preferably 20-40%. The filling height of the water collecting ditch 7 is flush with the top surface of the permeable base layer 3, and the upper surface of the water collecting ditch 7 is covered with geotextile and other reverse filter fabrics; emulsified asphalt is sprayed on the periphery and the bottom of the water collecting ditch 7 to serve as a waterproof layer, and the emulsified asphalt used for seal construction can be adopted.

(roadbed)

The roadbed 6 is compacted, and the degree of compaction is more than 93%.

The present invention will be further described with reference to the following examples.

Example 1:

the bituminous paving structure that permeates water of this embodiment includes bituminous mixture upper surface layer, bituminous mixture lower surface layer, the basic unit that permeates water, seal, the subbase that does not permeate water and road bed from the top down in proper order, and the bottom outside edge of the subbase that does not permeate water is equipped with the catch basin, packs the slag rubble in the catch basin.

Wherein, the upper layer of the asphalt mixture adopts a steel slag permeable asphalt mixture PAC-13 with the nominal maximum grain diameter of 13.2mm, the mixing amount of steel slag aggregate in the upper layer of the asphalt mixture is 80 percent, and the rest is stone and organic binder, and the organic binder adopts high-viscosity modified asphalt. The void ratio of the upper surface layer of the asphalt mixture is 19.1 percent, and the thickness is 4 cm.

The lower layer of the asphalt mixture adopts a steel slag permeable asphalt mixture PAC-20 with the nominal maximum grain diameter of 19mm, the mixing amount of steel slag aggregate in the lower layer of the asphalt mixture is 80 percent, and the rest is stone material. The void ratio of the lower surface layer of the asphalt mixture is 22.6 percent, and the thickness is 7 cm.

The mixing amount of the steel slag aggregate in the permeable base layer is 70 percent, the mixing amount of the cement is 6 percent, and the balance is the broken stone. The paving thickness of the permeable base layer is 30cm, and the porosity is 20.1%.

The seal coat is sprayed with emulsified asphalt with solid content of 60% and the thickness is 0.5 cm.

The mixing amount of the steel slag aggregate in the non-permeable subbase layer is 60 percent, the mixing amount of the inorganic binder is 30 percent, and the balance is the macadam. The ratio of the amount of the fly ash to the amount of the lime in the inorganic binder is 3: 1. The thickness of the non-permeable base layer is 18cm, and the outer edge of the bottom of the non-permeable base layer is provided with a water collecting ditch. The width of the water collecting ditch is 40cm, and the bottom of the water collecting ditch is provided with a water guide pipe. The diameter of the water guide pipe is 100mm, the longitudinal gradient is 0.28%, and the pipe bottom of the water guide pipe is flush with the bottom surface of the non-permeable subbase layer. Emulsified asphalt is sprayed on the inner wall of the water collecting channel, and steel slag, slag and crushed stone are filled in the water collecting channel, wherein the mixing amount of the steel slag is 65 percent, the mixing amount of the zeolite is 30 percent, and the mixing amount of the blast furnace slag is 5 percent.

Example 2:

Wherein, the upper layer of the asphalt mixture adopts a steel slag permeable asphalt mixture PAC-13 with the nominal maximum grain diameter of 13.2mm, the mixing amount of steel slag aggregate in the upper layer of the asphalt mixture is 80 percent, and the rest is stone and organic binder, and the organic binder adopts high-viscosity modified asphalt. The void ratio of the upper surface layer of the asphalt mixture is 19.4 percent, and the thickness is 5 cm.

The lower layer of the asphalt mixture adopts a steel slag permeable asphalt mixture PAC-20 with the nominal maximum grain diameter of 19mm, the mixing amount of steel slag aggregate in the lower layer of the asphalt mixture is 80 percent, and the rest is stone material. The void ratio of the lower surface layer of the asphalt mixture is 21.2 percent, and the thickness is 8 cm.

The mixing amount of the steel slag aggregate in the permeable base layer is 60 percent, the mixing amount of the fly ash is 25 percent, the mixing amount of the lime is 8 percent, and the balance is the broken stone. The paving thickness of the permeable base layer is 35cm, and the porosity is 22.6%.

The sealing layer is sprayed with No. 70 matrix asphalt and has a thickness of 0.6 cm.

The mixing amount of the steel slag aggregate in the non-permeable subbase layer is 80 percent, the mixing amount of the lime is 9 percent, and the rest is stone. The thickness of the non-permeable base layer is 20cm, and the outer edge of the bottom of the non-permeable base layer is provided with a water collecting ditch. The width of the water collecting ditch is 40cm, and the bottom of the water collecting ditch is provided with a water guide pipe. The diameter of the water guide pipe is 100mm, the longitudinal gradient is 0.29%, and the pipe bottom of the water guide pipe is flush with the bottom surface of the non-permeable subbase layer. The inner wall of the water collecting channel is sprayed with emulsified asphalt and is filled with steel slag, slag and crushed stone, wherein the mixing amount of the steel slag is 60 percent, the mixing amount of the zeolite is 30 percent, and the mixing amount of the blast furnace slag is 10 percent.

Example 3:

Wherein, the upper layer of the asphalt mixture adopts a steel slag permeable asphalt mixture PAC-13 with the nominal maximum grain diameter of 13.2mm, the mixing amount of steel slag aggregate in the upper layer of the asphalt mixture is 40 percent, and the rest is stone and organic binder, and the organic binder adopts high-viscosity modified asphalt. The void ratio of the upper surface layer of the asphalt mixture is 18.4 percent, and the thickness is 5 cm.

The lower layer of the asphalt mixture adopts a steel slag permeable asphalt mixture PAC-20 with the nominal maximum grain diameter of 19mm, the mixing amount of steel slag aggregate in the lower layer of the asphalt mixture is 40 percent, and the rest is stone material. The void ratio of the lower surface layer of the asphalt mixture is 20.3 percent, and the thickness is 8 cm.

The mixing amount of the steel slag aggregate in the permeable base layer is 50 percent, the mixing amount of the fly ash is 28 percent, the mixing amount of the lime is 7 percent, and the balance is the broken stone. The paving thickness of the permeable base layer is 38cm, and the porosity is 20.4%.

The mixing amount of the steel slag aggregate in the non-permeable subbase layer is 85 percent, the mixing amount of the lime is 10 percent, and the rest is stone. The thickness of the non-permeable base layer is 25cm, and the outer side edge of the bottom of the non-permeable base layer is provided with a water collecting ditch. The width of the water collecting ditch is 45cm, and the bottom of the water collecting ditch is provided with a water guide pipe. The diameter of the water guide pipe is 120mm, the longitudinal gradient is 0.27%, and the pipe bottom of the water guide pipe is flush with the bottom surface of the non-permeable subbase layer. Emulsified asphalt is sprayed on the inner wall of the water collecting channel, and steel slag, slag and crushed stone are filled, wherein the mixing amount of the steel slag is 70%, the mixing amount of the zeolite is 20%, the mixing amount of the vermiculite is 5%, and the mixing amount of the blast furnace slag is 5%.

Example 4:

Wherein, the upper layer of the asphalt mixture adopts a steel slag permeable asphalt mixture PAC-10 with the nominal maximum grain diameter of 9.5mm, the mixing amount of steel slag aggregate in the upper layer of the asphalt mixture is 80 percent, and the rest is stone and organic binder, and the organic binder adopts high-viscosity modified asphalt. The void ratio of the upper surface layer of the asphalt mixture is 18.4 percent, and the thickness is 5 cm.

The lower layer of the asphalt mixture adopts a steel slag permeable asphalt mixture PAC-20 with the nominal maximum grain diameter of 19mm, the mixing amount of steel slag aggregate in the lower layer of the asphalt mixture is 80 percent, and the rest is stone material. The void ratio of the lower surface layer of the asphalt mixture is 20.3 percent, and the thickness is 8 cm.

The mixing amount of the steel slag aggregate in the non-permeable subbase layer is 85 percent, the mixing amount of the lime is 10 percent, and the rest is stone. The thickness of the non-permeable base layer is 25cm, and the outer side edge of the bottom of the non-permeable base layer is provided with a water collecting ditch. The width of the water collecting ditch is 45cm, and the bottom of the water collecting ditch is provided with a water guide pipe. The diameter of the water guide pipe is 120mm, the longitudinal gradient is 0.27%, and the pipe bottom of the water guide pipe is flush with the bottom surface of the non-permeable subbase layer. Emulsified asphalt is sprayed on the inner wall of the water collecting channel, and steel slag, slag and crushed stone are filled in the water collecting channel, wherein the mixing amount of the steel slag is 65 percent, the mixing amount of the zeolite is 30 percent, and the mixing amount of the blast furnace slag is 5 percent.

Example 5:

Wherein, the upper layer of the asphalt mixture adopts a steel slag permeable asphalt mixture PAC-10 with the nominal maximum grain diameter of 9.5mm, the mixing amount of steel slag aggregate in the upper layer of the asphalt mixture is 60 percent, and the rest is stone and organic binder, and the organic binder adopts high-viscosity modified asphalt. The void ratio of the upper surface layer of the asphalt mixture is 18.4 percent, and the thickness is 5 cm.

The lower layer of the asphalt mixture adopts a steel slag permeable asphalt mixture PAC-20 with the nominal maximum grain diameter of 19mm, the mixing amount of steel slag aggregate in the lower layer of the asphalt mixture is 60 percent, and the rest is stone material. The void ratio of the lower surface layer of the asphalt mixture is 20.3 percent, and the thickness is 8 cm.

The mixing amount of the steel slag aggregate in the non-permeable subbase layer is 85 percent, the mixing amount of the lime is 10 percent, and the rest is stone. The thickness of the non-permeable base layer is 25cm, and the outer side edge of the bottom of the non-permeable base layer is provided with a water collecting ditch. The width of the water collecting ditch is 45cm, and the bottom of the water collecting ditch is provided with a water guide pipe. The diameter of the water guide pipe is 120mm, the longitudinal gradient is 0.27%, and the pipe bottom of the water guide pipe is flush with the bottom surface of the non-permeable subbase layer. Emulsified asphalt is sprayed on the inner wall of the water collecting channel, and steel slag, slag and crushed stone are filled, wherein the mixing amount of the steel slag is 60%, the mixing amount of the zeolite is 25%, the mixing amount of the vermiculite is 5%, and the mixing amount of the blast furnace slag is 10%.

Comparative example 1:

the permeable asphalt pavement structure of the comparative example sequentially comprises an asphalt mixture upper surface layer, an asphalt mixture lower surface layer, a permeable base layer, a seal layer, a non-permeable subbase layer and a roadbed from top to bottom.

Wherein the upper layer of the asphalt mixture adopts fine-grain basalt permeable asphalt mixture PAC-13, and the organic binder adopts high-viscosity modified asphalt. The void ratio of the upper surface layer of the asphalt mixture is 20.0 percent, and the thickness is 5 cm.

The lower layer of the asphalt mixture adopts common basalt permeable asphalt mixture PAC-20, and the organic binder adopts high-viscosity modified asphalt. The void ratio of the lower surface layer of the asphalt mixture is 23.7 percent, and the thickness is 8 cm.

The mixing amount of the fly ash in the permeable base layer is 28 percent, the mixing amount of the lime is 7 percent, and the balance is the broken stone. The paving thickness of the permeable base layer is 40cm, and the porosity is 21.3%.

The seal coat is sprayed with emulsified asphalt, and the thickness is 0.5 cm.

The mixing amount of lime in the non-permeable subbase layer is 10 percent, and the rest is stone. The thickness of the non-permeable base layer is 25cm, and the outer side edge of the bottom of the non-permeable base layer is provided with a water collecting ditch. The width of the water collecting ditch is 40cm, and the bottom of the water collecting ditch is provided with a water guide pipe without filler. The diameter of the water guide pipe is 100mm, the longitudinal gradient is 0.28%, and the pipe bottom of the water guide pipe is flush with the bottom surface of the non-permeable subbase layer.

Comparative example 2:

Wherein, the upper surface layer of the asphalt mixture adopts fine-grain common basalt permeable asphalt mixture PAC-10, and the organic binder adopts high-viscosity modified asphalt. The void ratio of the upper surface layer of the asphalt mixture is 19.2 percent, and the thickness is 4 cm.

The lower layer of the asphalt mixture adopts common basalt permeable asphalt mixture PAC-20, and the organic binder adopts high-viscosity modified asphalt. The void ratio of the lower surface layer of the asphalt mixture is 22.5 percent, and the thickness is 7 cm.

The mixing amount of the cement in the permeable base layer is 8 percent, and the balance is broken stone. The paving thickness of the permeable base layer is 42cm, and the porosity is 22.1%.

The sealing layer is sprayed with No. 70 matrix asphalt and has a thickness of 0.5 cm.

The mixing amount of the fly ash in the non-permeable subbase layer is 25 percent, the mixing amount of the lime is 9 percent, and the rest is the stone. The thickness of the non-permeable base layer is 25cm, and the outer side edge of the bottom of the non-permeable base layer is provided with a water collecting ditch. The width of the water collecting ditch is 40cm, and the bottom of the water collecting ditch is provided with a water guide pipe without filler. The diameter of the water guide pipe is 120mm, the longitudinal gradient is 0.28%, and the pipe bottom of the water guide pipe is flush with the bottom surface of the non-permeable subbase layer.

TABLE 1 test data for the above examples and comparative examples

The doping amount of the surface steel slag in the example 3 reaches 40%, the resilience modulus of the pavement surface reaches more than 1000MPa, the doping amount of the surface steel slag in the example 5 reaches 60%, the resilience modulus of the pavement surface reaches more than 1100MPa, and the doping amounts of the surface steel slag in the examples 1, 2 and 4 reach 80%, and the resilience modulus of the pavement surface exceeds 1200 MPa. Therefore, the modulus of resilience of the pavement is increased along with the increase of the mixing amount of the pavement steel slag. The resilience modulus of the asphalt mixture surface layer of the common permeable pavement in the comparative example is only about 800MPa, and is lower than that of the steel slag permeable asphalt pavement. Compared with the conventional pavement aggregate, the steel slag particles doped with the aggregate have rich edges and corners and high strength, and provide stronger structural interlocking force for the steel slag permeable asphalt mixture. In addition, the steel slag surface has rich micropore structures, can adsorb asphalt binder, increases the proportion of structural asphalt and free asphalt, and improves the cohesive force of the steel slag permeable asphalt mixture, so that the steel slag permeable asphalt pavement layer designed by the invention has higher modulus of resilience. Therefore, the steel slag is doped into the pavement surface layer and the pavement base layer, so that the bearing capacity of the pavement is obviously improved, pavement diseases are reduced, and the service durability of the pavement is further improved.

The performance of the fillers such as steel slag, zeolite, vermiculite, blast furnace slag and the like filled in the water collecting ditch is similar to the properties of clay minerals, and the surface has more micropores, thereby having better physical adsorption and ion exchange functions. In addition, the steel slag contains more soluble Ca and Mg ions, and can generate precipitates with phosphate radicals to remove phosphorus-containing pollutants in rainwater. Meanwhile, the steel slag has an adsorption effect on ammonia nitrogen in rainwater, and calcium ions dissolved out of the steel slag can promote cation exchange between fillers such as zeolite, vermiculite and slag and the ammonia nitrogen in the rainwater. Therefore, the filler composed of the steel slag, the zeolite, the vermiculite, the blast furnace slag and the like has a good nitrogen removal effect.

In conclusion, the roller steel slag is reasonably mixed in the asphalt mixture surface layer, the permeable base layer, the non-permeable subbase layer and the internal drainage system of the pavement, so that the bearing capacity and the use durability of the permeable asphalt pavement are improved, and the pollutants containing phosphorus and nitrogen in rainwater are effectively reduced, thereby being beneficial to reducing the pollution of water resources.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. It will be readily apparent to those skilled in the art that various modifications to these embodiments and the generic principles defined herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments. Those skilled in the art should appreciate that many modifications and variations are possible in light of the above teaching without departing from the scope of the invention.

Claims

1. The utility model provides a bituminous paving structure permeates water which characterized in that: the road surface comprises an asphalt mixture surface layer, a permeable base layer, a seal layer, a non-permeable subbase layer and a roadbed from top to bottom, wherein a water collecting ditch is arranged at the edge of the outer side of the bottom of the non-permeable subbase layer, a water guide pipe is arranged at the bottom of the water collecting ditch, and steel slag crushed stones are filled in the water collecting ditch;

the mixing amount of the steel slag aggregate in the surface layer of the asphalt mixture is 30-90%;

the mixing amount of the steel slag aggregate in the permeable base layer is 50-70%;

the mixing amount of the steel slag aggregate in the non-permeable subbase layer is 40-90%;

the mixing amount of the steel slag in the water collecting channel is 50-80%;

the steel slag in the permeable asphalt pavement structure is roller slag, the content of free calcium oxide in the steel slag is less than 2%, the pulverization rate is less than 2%, and the crushing value is less than 20%.

2. The water-permeable asphalt pavement structure according to claim 1, characterized in that: the asphalt mixture surface layer also comprises stone and an organic binder, and the organic binder is high-viscosity modified asphalt; the water immersion expansion rate of the asphalt mixture surface layer is less than 2%.

3. The water-permeable asphalt pavement structure according to claim 1, characterized in that: the asphalt mixture surface layer comprises an asphalt mixture upper surface layer and an asphalt mixture lower surface layer, and the thickness of the asphalt mixture surface layer is 11-13 cm.

4. A water-permeable asphalt pavement structure according to claim 3, characterized in that: the upper layer of the asphalt mixture adopts the asphalt mixture with the nominal grain diameter of 9.5-13.2mm, the void ratio is 18-25%, and the thickness is 4-5 cm;

the lower layer of the asphalt mixture adopts the asphalt mixture with medium or large particle size, the void ratio is 18-25%, and the thickness is 7-8 cm; the nominal maximum grain size of the medium grain size is 13.2-19mm, and the nominal maximum grain size of the large grain size is 19-26.5 mm.

5. The water-permeable asphalt pavement structure according to claim 1, characterized in that: the paving thickness of the permeable base layer is 20-60cm, the void ratio is 15-25%, and the 7d compressive strength is not less than 3.5 Mpa;

the permeable base layer also comprises an inorganic binder, the mixing amount is 5-40%, and the balance is broken stone.

6. The permeable asphalt pavement structure according to claim 5, characterized in that: the inorganic binder is selected from more than one of slag, lime, fly ash and cement.

7. The water-permeable asphalt pavement structure according to claim 1, characterized in that: the thickness of the sealing layer is 0.5-1.0 cm.

8. The water-permeable asphalt pavement structure according to claim 1, characterized in that: the paving thickness of the non-permeable subbase layer is 15-30cm, and the 7d compressive strength is not less than 2.0 Mpa;

the non-permeable subbase layer also comprises inorganic binder with the mixing amount of 5-30% and the balance of broken stone.

9. The permeable asphalt pavement structure according to claim 8, characterized in that: the inorganic binder is selected from more than one of slag, lime, fly ash and cement.

10. The water-permeable asphalt pavement structure according to claim 1, characterized in that: the diameter of the water guide pipe is 70-150 mm; the tube bottom of the water guide tube is flush with the bottom surface of the non-permeable subbase layer; the width of the water collecting channel is 35-60cm, the longitudinal gradient of the water collecting channel is the same as that of the aqueduct and is not less than 0.25%, slag and broken stone are filled in the water collecting channel, the mixing amount of the slag and the broken stone is 20-50%, and the broken stone comprises zeolite and/or vermiculite;

the filling height of the water collecting ditch is flush with the top surface of the permeable base layer, and the upper surface of the water collecting ditch is covered with a reverse filtering fabric; and emulsified asphalt is sprayed on the periphery and the bottom of the water collecting ditch.

11. The water-permeable asphalt pavement structure according to claim 1, characterized in that: the roadbed is compacted, and the degree of compaction is greater than 93%.