CN111485470A

CN111485470A - Highway road surface structure that waste residue utilized

Info

Publication number: CN111485470A
Application number: CN202010377523.3A
Authority: CN
Inventors: 李娜; 马润前; 贾德生; 徐希娟; 郭鹏飞; 张名成; 李晓娟; 周新锋
Original assignee: Shaanxi Yulin Highway Administration; Xian Highway Research Institute
Current assignee: Shaanxi Yulin Highway Administration; Xian Highway Research Institute
Priority date: 2020-05-07
Filing date: 2020-05-07
Publication date: 2020-08-04

Abstract

The invention belongs to the field of pavement structures, and discloses a waste residue utilization highway pavement structure which comprises an underlayer, a base layer, a lower layer and an upper layer, wherein the underlayer, the base layer, the lower layer and the upper layer are laid from bottom to top; the subbase layer is a cement waste residue stable aeolian sand subbase layer; the pavement is simple in structure, the prestressed concrete layer is used as the lower surface layer, the advantage of high strength of the prestressed concrete is utilized, and the longitudinal and transverse compressive stresses are applied to the pavement by applying the oblique prestress, so that the bending tensile strength of the concrete slab is improved; the cement stable wind-blown sand sub-base adopts the waste residue of the power plant to replace part of wind-blown sand, which is beneficial to improving the compressive strength of the cement stable wind-blown sand sub-base, so that the unconfined compressive strength of the obtained cement waste residue stable wind-blown sand sub-base 7d is 2.0-2.8 MPa; the strength of the cement waste residue stabilized macadam aeolian sand base layer can still meet the requirements of the technical rules for constructing highway pavement base layers; and the effective utilization of the waste residue and the aeolian sand of the power plant can be realized, and the production cost is low.

Description

Highway road surface structure that waste residue utilized

Technical Field

The invention relates to the field of pavement structures, in particular to a highway pavement structure utilizing waste residues.

Background

In recent years, under the action of heavy traffic, asphalt pavements are often damaged, so that the service life of the pavements is affected. On the other hand, with the continuous deepening of the industrialization process of China, industrial solid wastes are increased year by year, and the coal-fired power plant is taken as the main body of the energy industry of China, the solid wastes generated every year not only cause huge pressure to the surrounding environment, but also cause resource waste.

The solid waste (i.e. power plant waste residue) of the coal-fired power plant is mainly generated in the coal-fired power generation process, and the coal powder is combusted at high temperature to form a mixed material similar to volcanic ash, which mainly comprises coal ash, waste residue, debris and the like. In addition, with the maturity of desulfurization technical conditions, the desulfurized gypsum becomes a main solid waste of modern coal-fired power plants. The pollution of the solid waste of the coal-fired power plant is stored in the open air or the chemical harmful components in the solid waste of the coal-fired power plant placed in a disposal site can be directly or indirectly transmitted to human bodies through environmental media, such as atmosphere, soil, surface or underground water, and the like, thereby threatening health. The waste residue of the power plant is sintered coarse residue discharged from the bottom of the furnace after the coal of the power plant is combusted by the boiler, occupies a large amount of land accumulation, aggravates the land utilization contradiction, greatly destroys land resources and simultaneously causes various environmental problems.

At present, the solid waste of coal-fired power plants is mainly treated by adopting a landfill and stacking mode, and the method has the advantages of large floor area, high environmental pressure, high treatment cost and serious waste. The research on the resource utilization of the solid waste of the coal-fired power plant can be developed, and the dual effects of saving resources and protecting the environment can be realized.

In addition, wind-blown sand is widely distributed in northwest areas of China, and occupies about 17.9% of the total area of the national soil. The aeolian sand area has abundant natural resources, for example, the discovered oil and gas resources of only Takrama dry desert reach 160 hundred million tons, and the Shenfu coal field positioned at the south edge of Maowu desert is the largest coal field discovered in China and accounts for 15 percent of the discovered reserves in China. The traffic facilities in the aeolian sand area are weak, and with the advance of the western development, the road construction in the aeolian sand area can further improve the road network structure of the western area and promote the resource development of the western area and the development of social economy.

The problems faced in constructing roads in windy and sandy areas are: the road building material is deficient, and the building of traditional road surface structure mostly adopts materials such as lime soil, grit, needs to carry out long distance transportation, and is with high costs. The engineering application aspect of the aeolian sand in China is lack of systematic research and summary, the built aeolian sand can also face the hazards of wind erosion, sand burying and the like, and the maintenance and management cost is high.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a waste residue utilization expressway pavement structure which is simple in structure, low in production cost and capable of effectively utilizing power plant waste residues and wind-laid sand, and the obtained pavement structure meets the requirements of JTG/T F20-2015 (highway pavement base course construction technical rules).

In order to achieve the purpose, the invention is realized by adopting the following technical scheme.

A highway pavement structure utilizing waste residues comprises an underlayer, a base layer, a lower layer and an upper layer which are paved from bottom to top; the subbase layer is a cement waste residue stable aeolian sand subbase layer.

Preferably, the base layer is a cement waste residue stabilized macadam aeolian sand base layer.

Preferably, the lower surface layer is a prestressed concrete layer.

Preferably, the upper surface layer is an AC13 or AC16 asphalt surface layer.

Preferably, an adhesive layer is further provided between the lower layer and the upper layer.

Preferably, the thickness of the sub-base layer is 18-20 cm.

Preferably, the thickness of the base layer is 18-20 cm.

Preferably, the thickness of the lower layer is 20-24 cm.

Preferably, the thickness of the upper layer is 3-5 cm.

Preferably, the cement slag-stabilized aeolian sand sub-base layer comprises cement, power plant slag and aeolian sand.

Preferably, the cement waste residue stable wind-blown sand subbase layer comprises 5% -7% of cement, 20% -50% of power plant waste residue and the balance wind-blown sand.

Preferably, the cement waste residue stabilized macadam aeolian sand base layer comprises macadams, power plant waste residues, cement and aeolian sand.

Further preferably, the crushed stone has a particle size of 10-30 mm.

Preferably, the cement waste residue stabilized macadam aeolian sand base course comprises 30-40% of macadam, 20-30% of power plant waste residue, 6-8% of cement and the balance aeolian sand.

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

(1) the highway pavement structure utilizing the waste residues adopts the prestressed concrete layer as the lower surface layer, utilizes the advantage of high strength of the prestressed concrete, applies longitudinal and transverse compressive stresses to the pavement by applying oblique prestress, improves the bending tensile strength of a concrete plate, designs the original bending tensile strength of the concrete to be 5MPa, and can improve the strength by 20-40 percent after applying the prestress. The prestressed concrete layer interface adopts the stone embedding process and forms rivet connection with the asphalt surface layer, so that the interlaminar shear strength is improved, and compared with plain concrete (the shear strength is 0.674), the shear strength can be improved by 70%.

(2) The cement waste residue stabilized wind-blown sand subbase layer is made of power plant waste residue instead of part of wind-blown sand, so that the compressive strength of the cement waste residue stabilized wind-blown sand subbase layer is improved, the unconfined compressive strength of the cement waste residue stabilized wind-blown sand subbase layer 7d is 2.0-2.8MPa, the unconfined compressive strength of the cement waste residue stabilized wind-blown sand subbase layer 28d can reach 4.3-5.9MPa, and the requirements of heavy traffic roads are met.

(3) The strength of the cement waste residue stabilized macadam aeolian sand base can still meet the requirements of technical rules for highway pavement base construction (JTG/T F20-2015).

(4) The highway pavement structure utilizing the waste residues realizes the application of the waste residues and the aeolian sand of the power plant in the pavement structure, realizes the resource utilization of the waste residues and the aeolian sand of the industrial power plant, and simultaneously prolongs the service life of the asphalt pavement structure. Meanwhile, the aeolian sand can be obtained from local materials, and the road is built by utilizing abundant and cheap aeolian sand resources, so that the construction quality and the technical performance of highway engineering can be ensured, the construction cost can be greatly reduced, the energy conservation and emission reduction are realized, the ecological environment is protected, and the road building technical level of an aeolian sand area is improved.

Drawings

The invention is described in further detail below with reference to the figures and specific embodiments.

FIG. 1 is a schematic view of a highway pavement structure utilizing the waste slag of the present invention;

FIG. 2 is a comparison graph of screening results before and after compaction of power plant waste residues;

FIG. 3 is a 7-day water immersion scattering diagram of pure coal cinder;

in the above figures: 1, a bottom base layer; 2, a base layer; 3 lower layer; 4, upper layer.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention.

Referring to fig. 1, the highway pavement structure utilizing waste residues comprises an underlayer 1, a base layer 2, a lower underlayer 3 and an upper underlayer 4 which are laid from bottom to top, and the whole highway pavement structure utilizing waste residues is constructed by adopting an asphalt paver to pave.

The method specifically comprises the following steps:

(1) the upper surface layer 4 is a 3-5cm AC13 or AC16 asphalt surface layer, is a functional layer and a wearing layer of a pavement structure, and plays roles of resisting skidding of the pavement and improving the driving comfort. If the functional layer does not meet the anti-skid requirement and the service condition, a new wearing layer is paved after milling and planning treatment.

(2) The lower surface layer 3 is a prestressed concrete layer, the prestressed concrete layer is made of cement concrete with bending tensile strength of 5MPa, the arrangement angle of prestressed tendons is 30-45 degrees, and the distance is 0.5-1 m.

The prestressed concrete layer adopts interface treatment process, i.e. the broken stone is embedded into the concrete, i.e. stone-embedded interface, then the SBR modified emulsified asphalt is spread as bonding layer, and the spreading dosage of the bonding layer is 0.9L/m². The arrangement of the bonding layer can enhance the shear strength between the prestressed concrete layer and the asphalt surface layer.

(5) The base course 2 is a cement waste residue stabilized macadam aeolian sand base course 2, and 30-40% of 10-30mm macadam, 20-30% of power plant waste residue, 6-8% of cement and the balance aeolian sand are adopted.

(6) The subbase layer 1 is a cement waste residue stable aeolian sand subbase layer 1, and the cement waste residue stable aeolian sand subbase layer 1 comprises 5% -7% of cement, 20% -50% of power plant waste residue and the balance aeolian sand.

The screening results of the aeolian sand are shown in table 1.

TABLE 1 aeolian sand screening results (Square hole screen)

The chemical components of the power plant waste residue, the sieve pore passing rate before and after compaction and the adhesive property are analyzed, and the method specifically comprises the following steps:

1. chemical composition analysis of power plant waste residue

The waste residue from the coal-fired power plant was sampled and subjected to chemical composition analysis, and the results are shown in table 2.

TABLE 2 analysis results of chemical composition of waste residue from coal-fired power plant

As can be seen from Table 2, the main oxide composition of the power plant slag is silicon oxide (SiO)₂) Alumina (Al)₂O₃) Iron oxide (Fe)₂O₃) Calcium oxide (CaO); wherein, the silicon oxide, the aluminum oxide, the ferric oxide and the calcium oxide account for 93.19 percent of the total amount, which indicates that the power plant waste residue has certain activity. Therefore, the application of the power plant waste residue in highway engineering is feasible.

2. Analysis of sieve mesh passing rate before and after compaction of power plant waste residue

The results of analyzing the mesh passage rates before and after the power plant slag compaction are shown in table 3 and fig. 2.

TABLE 3 results of screening before and after compaction of the waste residues of the power plant

As can be seen from Table 3 and FIG. 2, the grading change of the power plant waste residue before and after compaction is obvious due to the high crushing value of the power plant waste residue, and the passing rates of 16mm and 13.2mm sieve pores are changed slightly and less than 10% under the action of compaction hammers; the 9.5mm mesh throughput rate varied by about 13%; the passing rates of the 4.75mm and 2.36mm sieve holes have the largest change range, which is about 20 percent; the passing rate of fine aggregates with meshes of 0.15mm to 1.18mm is changed by more than 10 percent. The crushing of the power plant waste residue is shown under the compaction effect, and the integral passing rate is increased.

3. Power plant slag cohesiveness analysis

The pure electric plant waste residue is made into an unconfined test piece, and the adhesiveness of the test piece is tested under the condition of not doping cement, and the result is shown in figure 3.

As can be seen from FIG. 3, the unconfined test piece of the waste residue of the pure electric plant is easy to break because the unconfined test piece is dispersed when meeting water, so that the waste residue of the pure electric plant has no adhesiveness.

Example 1

Stabilizing aeolian sand subbase layer 1 with cement waste residues: comprises 7 percent of cement, 20 percent of power plant waste residue and 73 percent of aeolian sand.

Example 2

Stabilizing aeolian sand subbase layer 1 with cement waste residues: comprises 7 percent of cement, 30 percent of power plant waste residue and 63 percent of aeolian sand.

Example 3

Stabilizing aeolian sand subbase layer 1 with cement waste residues: comprises 7 percent of cement, 40 percent of power plant waste residue and 53 percent of aeolian sand.

Example 4

Stabilizing aeolian sand subbase layer 1 with cement waste residues: comprises 7 percent of cement, 50 percent of power plant waste residue and 43 percent of aeolian sand.

Comparative example 1

Cement stabilized aeolian sand sub-base layer 1: comprises 7 percent of cement and 93 percent of aeolian sand.

Test 1

The test method comprises the following steps: the compressive strength and the coefficient of variation of the cement waste residue stabilized aeolian sand underlayment 1 obtained in the examples 1 to 4 in different amounts and the cement stabilized aeolian sand underlayment 1 obtained in the comparative example 1 in 7 days were respectively tested, and the test method refers to the test procedure of inorganic binder stabilized material for highway engineering test regulation JTG E51 (T0805).

And (3) test results: the test results are shown in Table 4, respectively.

TABLE 4 test results of Cement Stable aeolian Sand underlayment 1 and Cement slag Stable aeolian Sand underlayment 1

As can be seen from Table 4, the compressive strengths of examples 1-4 in 7 days are sequentially increased, and the compressive strengths in 28 days are sequentially increased, which shows that the compressive strength of the cement waste residue stabilized aeolian sand subbase 1 is gradually increased along with the increase of the mixing amount of the waste residue in the power plant; when the mixing amount of the waste residues in the power plant is 50%, the compressive strength of the cement waste residue stabilized aeolian sand subbase layer 1 reaches the maximum value of 2.8MPa in 7 days, and the compressive strength reaches the maximum value of 5.9MPa in 28 days. The compressive strength of the cement waste residue stabilized aeolian sand subbase 1 added with 20%, 30%, 40% and 50% of the power plant waste residue in the examples 1 to 4 in 7 days is larger than that (1.5MPa) of the cement stabilized aeolian sand subbase 1 in the comparative example 1 in 7 days, which shows that the adoption of the power plant waste residue in the cement stabilized aeolian sand subbase 1 to replace part of aeolian sand is beneficial to improving the compressive strength.

Test 2

The 7d compressive strength and the variation coefficient of the cement stabilized aeolian sand and the cement waste residue stabilized macadam aeolian sand base layer 2 are tested, and the test results are respectively shown in tables 5 and 6.

TABLE 5 test results of 7d compressive strength of cement stabilized wind-deposited sand

TABLE 6 compressive strength of cement waste residue stabilized macadam aeolian sand base course 2 in 7d

As can be seen from tables 5 and 6, the 7d unconfined compressive strength of the cement waste residue stabilized macadam aeolian sand base layer 2 is obviously higher than the 7d unconfined compressive strength of the cement stabilized aeolian sand. And the cement waste residue stabilized macadam aeolian sand base layer 2 has the unconfined 7d compressive strength of 3.4-4.2MPa when the cement consumption is 6%, and has the unconfined 7d compressive strength of 4.5-5.6MPa when the cement consumption is 7-8%.

The requirements of the standard of 7d unconfined compressive strength of a road structure layer in the existing detail rule of construction technology for road base course 2 (JTG/T F20-2015) are shown in Table 7.

TABLE 7 Standard requirements for structural layers of roads

As can be seen from tables 4 and 7, the unconfined compressive strength of the cement waste residue stable wind sand accumulation subbase 17d is 2.0-2.8MPa, and the requirement of the heavy traffic road subbase 1 structure is met.

As can be seen from tables 6 and 7, the unconfined compressive strength of 7d of the cement waste residue stabilized macadam aeolian sand base course 2 can reach 3.4-4.2MPa when the cement consumption is 6%, and the structural requirements of the base course 2 of medium and light traffic roads are met; when the cement consumption is 7-8%, the 7d unconfined compressive strength can reach 4.5-5.6MPa, and the requirement of the base layer 2 structure of extremely heavy and extra heavy traffic roads is met.

Although the present invention has been described in detail in this specification with reference to specific embodiments and illustrative embodiments, it will be apparent to those skilled in the art that modifications and improvements can be made thereto based on the present invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. A highway pavement structure utilizing waste residues is characterized by comprising an underlayer, a base layer, a lower layer and an upper layer which are paved from bottom to top; the subbase layer is a cement waste residue stable aeolian sand subbase layer.

2. A highway pavement structure utilizing waste slag according to claim 1 wherein said base course is a cement waste slag stabilized macadam aeolian sand base course.

3. A highway pavement structure utilizing waste slag according to claim 1 wherein said lower surface layer is a prestressed concrete layer.

4. The highway pavement structure utilizing waste slag according to claim 1, wherein the upper surface layer is an AC13 or AC16 asphalt surface layer.

5. A highway pavement structure utilizing waste slag according to claim 1, wherein an adhesive layer is further provided between said lower surface layer and said upper surface layer.

6. A highway pavement structure utilizing waste slag according to claim 1, wherein said sub-base has a thickness of 18-20 cm; the thickness of the base layer is 18-20 cm.

7. A highway pavement structure utilizing waste slag according to claim 1, wherein said lower surface layer has a thickness of 20-24 cm; the thickness of the upper layer is 3-5 cm.

8. A highway pavement structure utilizing waste residues as recited in claim 1 wherein said cement waste residue stabilizing aeolian sand sub-base layer comprises 5-7% cement, 20-50% power plant waste residues, and the balance aeolian sand.

9. A highway pavement structure utilizing waste residues as recited in claim 2, wherein said cement waste residue stabilized macadam aeolian sand base course comprises 30-40% of macadam, 20-30% of power plant waste residue, 6-8% of cement, and the balance aeolian sand.

10. A highway pavement structure utilizing waste slag according to claim 9, wherein said crushed stone has a particle size of 10-30 mm.