A high-performance modified asphalt pavement structure

Abstract

The present invention discloses a high-performance modified asphalt pavement structure, comprising, from top to bottom, an upper layer of a discontinuously graded skeleton-dense RMS rubber composite modified asphalt mixture, a middle layer of a continuously graded suspended dense RMH rubber composite modified asphalt mixture, and a lower layer of a continuously graded suspended dense RMB rubber composite modified asphalt mixture; the upper, middle and lower layers respectively use three different rubber composite modified asphalts, so that the upper layer has good anti-aging performance and durability, the middle layer has good high-temperature performance, and the lower layer has good fatigue cracking resistance; the raw materials of the present invention are easily obtained, the process is simple and easy to operate, and the operability is strong, and the present invention is suitable for large-scale promotion and application in asphalt pavement projects.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt pavement, and in particular to a high-performance modified asphalt pavement structure. Background Art

[0002] In order to improve the durability of asphalt pavements and extend the service life of roads, in the existing technical solutions, there is a long-life asphalt pavement structure with application number 202220969516.7, whose pavement structure includes a reinforcement layer, an asphalt base layer, a waterproof layer, a drainage layer and an asphalt surface layer. The reinforcement layer of the pavement structure is provided with reinforcing columns, and the asphalt layer is paved with a mesh, which can effectively improve the firmness and durability of the asphalt pavement, but the performance of the different structural layers of the pavement is not verified. Similarly, there is a rubber asphalt pavement structure with application number 202120544797.7, which includes a baffle, a sub-baffle, a base plate and upper and lower asphalt layers. The base plate is fixed with columns, and the baffle is used to reduce the loss of asphalt materials. This technology is different from traditional pavement paving technology, and the performance effect is not explained in detail, which is not conducive to promotion and implementation.

[0003] Therefore, considering the importance of solving pavement diseases, improving pavement quality and extending road service life, it is necessary to design a high-performance modified asphalt pavement structure. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the purpose of the present invention is to provide a high-performance modified asphalt pavement structure. This structure designs the asphalt mixture composition according to the functional requirements of different pavement layers, and combines the superior performance of rubber composite modified asphalt to improve the durability of the pavement and extend the service life of the road.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A high-performance modified asphalt surface layer structure comprises, from top to bottom, a discontinuously graded skeleton dense RMS rubber composite modified asphalt mixture upper layer (1), a non-stick wheel special emulsified asphalt bonding layer (2), a continuously graded suspended dense RMH rubber composite modified asphalt mixture middle layer (3), a modified emulsified asphalt waterproof layer (4), and a continuously graded suspended dense RMB rubber composite modified asphalt mixture lower layer (5).

[0007] As a further preferred embodiment of the technical solution of the present invention, the RMS rubber composite modified asphalt is prepared from the following raw materials, in parts by weight: 5 to 20 parts of waste rubber powder, 90 to 100 parts of matrix asphalt, 5 to 15 parts of diatomaceous earth, 1 to 4 parts of SBS, and 0.5 to 5 parts of ferric oxide.

[0008] Further preferably, the preparation method of RMS rubber composite modified asphalt is as follows:

[0009] S1. Preheat the base asphalt at 120-150°C for 1-3 hours to make it fluid; then quickly and evenly heat it to 180-200°C;

[0010] S2. Add SBS to the asphalt heated in step S1, stir for 10-30 minutes to fully mix with the matrix asphalt, and then shear at 180-200°C and 6000-8000 r / min for 0.5-1.5 hours;

[0011] S3, adding waste rubber powder, diatomaceous earth and ferric oxide to the molten mixture of asphalt and SBS obtained in step S2, and shearing at 180-200° C. and 2000-4000 r / min for 0.5-1 h;

[0012] S4. After the stirring is completed, the mixture is placed in an oven at 150-180° C. for curing for 1-3 hours to obtain the RMS rubber composite modified asphalt.

[0013] In the above technical solution, SBS needs to be modified by high-speed shearing using a high-speed shearing machine. High-speed shearing allows SBS to be evenly dissolved in asphalt to form a uniformly distributed SBS network structure, thereby increasing the viscosity and anti-rutting performance of the asphalt. After adding waste rubber powder, the shear speed is reduced, and the rubber powder particles absorb low-molecular components in the asphalt and swell, further modifying the asphalt. However, if rubber powder and SBS are added to asphalt together, the rubber powder will absorb a large amount of light components to swell and the high-speed shearing will cause it to break. The SBS cannot absorb enough light components to swell and form a network cross-linked structure, resulting in a poor asphalt modification effect.

[0014] As a further preferred embodiment of the technical solution of the present invention, the RMH rubber composite modified asphalt is prepared from the following raw materials, in parts by weight: 20 to 40 parts of waste rubber powder, 100 to 120 parts of matrix asphalt, 1 to 10 parts of diatomaceous earth, 1 to 2 parts of SBS, and 1 to 10 parts of ferric oxide.

[0015] In the above technical solution, the amount of rubber added in RMH rubber composite modified asphalt is increased compared to RMS rubber composite modified asphalt. This is because studies have found that with the increase in the amount of rubber powder added, the needle penetration of SBS / rubber composite modified asphalt becomes smaller, and the softening point, elastic recovery, and 177°C Brookfield rotation viscosity all increase significantly, and the high-temperature performance is significantly improved.

[0016] Further preferably, the preparation method of RMH rubber composite modified asphalt is as follows:

[0017] (1) Preheat the base asphalt at 120-150°C for 1-3 hours to make it fluid; then quickly and evenly heat it to 180-200°C;

[0018] (2) adding SBS to the asphalt heated in step (1), stirring for 10 to 30 minutes to fully mix with the matrix asphalt, and then shearing at 180 to 200° C. and 6,000 to 8,000 r / min for 0.5 to 1.5 hours;

[0019] (3) adding waste rubber powder, diatomaceous earth and ferric oxide to the molten mixture of asphalt and SBS obtained in step (2), and shearing at 180-200° C. and 2000-4000 r / min for 0.5-1 h;

[0020] (4) After the stirring is completed, the asphalt is placed in an oven at 150-180° C. for curing for 1-3 hours to obtain the RMH rubber composite modified asphalt.

[0021] As a further preferred embodiment of the technical solution of the present invention, the RMB rubber composite modified asphalt is prepared from the following raw materials, in parts by weight: 25-45 parts of waste rubber powder, 120-150 parts of matrix asphalt, 1-20 parts of diatomaceous earth, 1-3 parts of SBS, 1-20 parts of ferric oxide, and 1-15 parts of cement.

[0022] In the above technical solution, the addition of cement can enhance the ability of the mixture to resist rutting deformation, especially reduce the attenuation of the mixture's anti-rutting ability in the presence of water, and delay the rate of rutting deformation and damage of the asphalt pavement in the presence of water; this is because the specific surface area of ​​cement is relatively large and its adsorption capacity for asphalt is stronger. At the same time, the alkaline component CaO in cement has a higher content and is more active. It can react with weakly acidic asphalt to generate a binder with strong bonding properties, which firmly adheres to the aggregate surface, thereby enhancing the interaction between asphalt and aggregate, improving the overall structural stability of the mixture, and reducing the possibility of flow deformation of the pavement under the combined action of high temperature and water.

[0023] Further preferably, the preparation method of RMB rubber composite modified asphalt is as follows:

[0024] (1) Preheat the base asphalt at 120-150°C for 1-3 hours to make it fluid; then quickly and evenly heat it to 180-200°C;

[0025] (2) adding SBS to the asphalt heated in step (1), stirring for 10 to 30 minutes to fully mix with the matrix asphalt, and then shearing at 180 to 200° C. and 6,000 to 8,000 r / min for 0.5 to 1.5 hours;

[0026] (3) adding waste rubber powder, diatomaceous earth, ferric oxide and cement to the molten mixture of asphalt and SBS obtained in step (2), and shearing at 180-200° C. and 2000-4000 r / min for 0.5-1 h;

[0027] (4) After the stirring is completed, the asphalt is placed in an oven at 150-180° C. for curing for 1-3 hours to obtain the RMH rubber composite modified asphalt.

[0028] In the above technical solution, the waste rubber powder is processed from waste tires and has a particle size of 40-80 mesh; the asphalt can be selected from one of Grade A No. 50, No. 70, or No. 90 road asphalts that meet JTG F40-2004 "Technical Specifications for Highway Asphalt Pavement Construction"; the SBS can be oil-extended or non-oil-extended linear or star-shaped SBS; the diatomaceous earth used has a fineness of 100-300 mesh, and the main components of the diatomaceous earth are: 80-90% silicon dioxide, 3-5% magnesium oxide, 1-5% calcium oxide, 1-5% iron oxide, and other impurities; and the cement used can be ordinary Portland cement, which is not specifically limited in the present invention.

[0029] It can be understood that the asphalt mixture used in the upper, middle and lower surface layers of the present invention includes not only the corresponding modified asphalt, but also coarse aggregate, fine aggregate and filler; as a further preference of the technical solution of the present invention, the coarse aggregate used is selected from one or more of basalt, limestone and diabase, the fine aggregate is limestone, and the filler is limestone mineral powder.

[0030] The rubber composite modified asphalt mixtures of the upper, middle and lower surface layers of the present invention include contents such as mineral aggregate gradation design and optimal oil-to-rock ratio design; through the mineral aggregate gradation design, the material ratio of coarse and fine aggregates is determined so that the mineral aggregate gradation of the asphalt mixture meets the design requirements; on this basis, asphalt mixtures with different composition ratios of rubber composite modified asphalt and mineral aggregate are mixed, and the composition ratio of rubber composite modified asphalt and mineral aggregate with better performance in all aspects is determined through Marshall compaction test and test calculation of related parameters, and this ratio is used as the optimal oil-to-rock ratio.

[0031] As a further preferred embodiment of the technical solution of the present invention, the oil-stone ratio of the upper layer of the discontinuous-graded skeleton-dense RMS rubber composite modified asphalt mixture is 6.2-6.6%; the oil-stone ratio of the middle layer of the continuously-graded suspended-dense RMH rubber composite modified asphalt mixture is 4.4-4.6%; and the oil-stone ratio of the lower layer of the continuously-graded suspended-dense RMB rubber composite modified asphalt mixture is 4.2-4.4%.

[0032] As a further preferred embodiment of the technical solution of the present invention, the key sieve hole 13.2mm pass rate of the aggregate used for the upper layer of the discontinuous-graded skeleton dense RMS rubber composite modified asphalt mixture is 90% to 94%, the sieve hole 4.75mm pass rate is 20% to 30%, and the sieve hole 0.075mm pass rate is 8% to 10%; the key sieve hole 19mm pass rate of the aggregate used for the middle layer of the continuous-graded suspended dense RMH rubber composite modified asphalt mixture is 92% to 98%, the sieve hole 4.75mm pass rate is 25% to 35%, and the sieve hole 0.075mm pass rate is 4% to 7%; the key sieve hole 26.5mm pass rate of the aggregate used for the lower layer of the continuous-graded suspended dense RMB rubber composite modified asphalt mixture is 92% to 96%, the sieve hole 4.75mm pass rate is 22% to 30%, and the sieve hole 0.075mm pass rate is 3% to 6%.

[0033] As a further preferred embodiment of the technical solution of the present invention, the thickness of the upper layer of the discontinuous-graded skeleton dense rubber composite modified asphalt mixture is 3.5 to 4.5 cm; the thickness of the middle layer of the continuously-graded suspended dense rubber composite modified asphalt mixture is 5.5 to 6.5 cm; and the thickness of the lower layer of the continuously-graded suspended dense rubber composite modified asphalt mixture is 7.5 to 8.5 cm.

[0034] As a further preferred embodiment of the technical solution of the present invention, a non-stick wheel special emulsified asphalt bonding layer is provided between the upper layer of the discontinuous-graded skeleton dense rubber composite modified asphalt mixture and the middle layer of the continuously-graded suspended dense rubber composite modified asphalt mixture; and a modified emulsified asphalt waterproofing layer is provided between the middle layer of the continuously-graded suspended dense rubber composite modified asphalt mixture and the lower layer of the continuously-graded suspended dense rubber composite modified asphalt mixture.

[0035] As a further preferred embodiment of the technical solution of the present invention, the non-stick wheel special emulsified asphalt is prepared from the following raw materials, in parts by weight: 45 to 65 parts of base asphalt, 1 to 5 parts of emulsifier, 0.1 to 3 parts of stabilizer, 0.5 to 3 parts of pH regulator, 0.5 to 5 parts of polymer modifier, and 40 to 50 parts of water.

[0036] Further preferably, the preparation method of the special emulsified asphalt for non-stick wheels is as follows:

[0037] (1) Dissolve the emulsifier, stabilizer, polymer modifier, and pH adjuster in 50-75°C hot water, stir evenly, and prepare a soap solution;

[0038] (2) heating the matrix asphalt to 150-170°C to make it fluid;

[0039] (3) The soap solution prepared in step (1) and the base asphalt in the flowing state in step (2) are mixed, and the mixture is sheared at a high speed by a colloid mill at a rotation speed of 5000 to 8000 r / min to obtain a non-stick wheel special emulsified asphalt.

[0040] In the above technical solution, the polymer modifier is any one of pure acrylic emulsion, vinyl acetate acrylic emulsion, styrene acrylic emulsion, polyurethane emulsion, silicone acrylic emulsion, polyvinyl acetate emulsion, vinyl acetate-ethylene copolymer emulsion (EVA emulsion), and chloroprene rubber latex, or is formed by mixing two or more of the above emulsions in any proportion; polyurethane emulsion is preferred.

[0041] As a further preferred embodiment of the technical solution of the present invention, the modified emulsified asphalt is prepared from the following raw materials, in parts by weight: 50-70 parts of base asphalt, 3-10 parts of emulsifier, 1-3 parts of stabilizer, 40-60 parts of cement, 40-55 parts of filler, and 1-5 parts of additive.

[0042] Further preferably, the modified emulsified asphalt preparation method is as follows:

[0043] Dissolve the emulsifier and stabilizer in water, then add the flowing matrix asphalt, stir evenly, and then mix with cement, filler and additives.

[0044] The special emulsified asphalt for non-stick wheels and the modified emulsified asphalt of the present invention further require emulsifiers, stabilizers, pH regulators, etc. during the preparation process, which are all conventional auxiliary materials in the field; preferably, the emulsifier can be a fast-cracking emulsifier, such as hexadecyltrimethylammonium bromide or alkylpropylenediamine; the stabilizer is preferably a cellulose stabilizer such as hydroxymethyl cellulose or hydroxyethyl cellulose; the pH regulator can be any one of hydrochloric acid, phosphoric acid, sulfuric acid, sodium hydroxide or potassium hydroxide.

[0045] The cement used in the modified emulsified asphalt waterproof layer of the present invention can be selected from white cement or gray cement; the filler can be selected from one or more of calcium carbonate, talc powder, wollastonite powder, and quartz sand; the auxiliary agent is selected from one or more of water reducers, stabilizers, and thickeners; wherein the water reducer and the thickener are conventional auxiliary materials in the field, for example, the water reducer can be a polycarboxylic acid water reducer or a naphthalene water reducer; the thickener can be a cellulose ether, etc.

[0046] It is understood that during the construction process, the spreading amount of the above-mentioned non-stick wheel special emulsified asphalt and modified emulsified asphalt can be flexibly adjusted according to the actual situation of the construction site, and the present invention does not make specific restrictions on this. As a preferred technical solution of the present invention, the spreading amount of the non-stick wheel special emulsified asphalt is 0.5-1.5 kg / m 2 The spreading amount of modified emulsified asphalt is 0.8~2kg / m 2 .

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. The three types of rubber-composite modified asphalts of the present invention are all prepared by composite modification of waste rubber powder and SBS. The addition of rubber powder maximizes the modification effect of rubber powder and SBS, and the two modifiers promote and complement each other, further improving the performance of asphalt, so that it has good road performance such as high and low temperature stability, fatigue resistance, water stability, and aging resistance, which is significantly superior to simple SBS and rubber powder modified asphalt mixtures. In addition, the raw material waste rubber powder used in the present invention is processed from waste tires, which effectively realizes the recycling of waste resources and has good social and environmental benefits. Only a small amount of SBS is added to the modified asphalt, further reducing engineering costs. The equivalent annual cost per ton per year of the rubber-composite modified asphalt mixture of the present invention is 36% lower than that of the SBS modified asphalt mixture, which has a great advantage in economic benefits.

[0049] 2. Diatomaceous earth is added to all three types of rubber composite modified asphalt. Diatomaceous earth is physically mixed with asphalt due to its porous, large specific surface area, and extremely strong adsorption capacity, which can effectively adsorb asphalt. After being added, diatomaceous earth acts as a rigid component, which significantly improves the anti-aging properties of asphalt and extends its service life. Ferric oxide is added to desulfurize the rubber powder, allowing it to swell better in asphalt, and the entire system has good fluidity during preparation. Furthermore, the applicant found that the combined use of ferric oxide and diatomaceous earth has a significantly better desulfurization effect than the use of ferric oxide alone. The possible reason is that ferric oxide can synergize with magnesium oxide and calcium oxide in diatomaceous earth to further improve the desulfurization efficiency.

[0050] 3. The raw material compositions of the modified asphalts in the upper, middle, and lower layers of the present invention are slightly different: the upper layer RMS rubber composite modified asphalt incorporates a larger amount of diatomaceous earth to ensure good anti-aging performance, the middle layer RMH rubber composite modified asphalt increases the rubber incorporation amount to obtain good high-temperature performance, and the incorporation of cement in the lower layer RMB rubber composite modified asphalt enhances fatigue cracking resistance. The present invention adopts different modified asphalts based on the functional requirements of different pavement layers, thereby improving the road performance of the mixture as a whole and extending the service life of the road. In terms of the preparation method, SBS and rubber powder are added successively and different shear speeds are adopted to further enhance the asphalt modification effect.

[0051] 4. The present invention adopts a discontinuous-graded skeleton dense mixture as the upper layer, which is an ideal structural type with good density, strength and stability. Moreover, compared with the continuous gradation, the discontinuous-graded mixture as the surface layer has significantly better rutting resistance under the combined action of water and heat. The middle and lower layers adopt a continuous-graded mixture because the high-temperature performance of the continuously graded rubber asphalt mixture is better than that of the discontinuous-graded rubber asphalt mixture. The use of three-layer rubber asphalt mixture can give full play to the technical characteristics and pavement performance of rubber asphalt, greatly improving the fatigue deformation resistance, rutting resistance and cracking resistance of the entire asphalt surface layer.

[0052] 5. Furthermore, a non-stick wheel special emulsified asphalt bonding layer is set between the upper layer and the middle surface layer, which can effectively reduce the construction gap between the tack layer construction and the asphalt mixture construction, thereby improving the adhesion between the tack layer material and the surface layer; a modified emulsified asphalt waterproof layer is set between the middle surface layer and the lower layer, which can effectively prevent rainwater from seeping into the pavement structure layer, protect the surface layer structure from rainwater erosion, and reduce the occurrence of water damage in the pavement structure layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a schematic diagram of the structure of the high-performance modified asphalt surface layer of the present invention;

[0054] Figure 2 Schematic diagram of the cross-sectional structure of the high-performance modified asphalt pavement structure of the present invention;

[0055] Among them, 1. The upper layer of the RMS rubber composite modified asphalt mixture with discontinuous gradation and skeleton density; 2. The non-stick wheel special emulsified asphalt bonding layer; 3. The middle layer of the RMH rubber composite modified asphalt mixture with continuous gradation and suspension density; 4. The modified emulsified asphalt waterproof layer; 5. The lower layer of the RMB rubber composite modified asphalt mixture with continuous gradation and suspension density. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0057] Although the steps in the present invention are arranged with numbers, they are not intended to limit the order of the steps. Unless the order of the steps is clearly stated or the execution of a step requires other steps as a basis, the relative order of the steps can be adjusted. It is understood that the term "and / or" used herein refers to and covers any and all possible combinations of one or more of the associated listed items.

[0058] Unless otherwise specified, the raw materials used in the present invention are purchased from the market or synthesized from the raw materials purchased from the market.

[0059] Example 1

[0060] like Figure 1 As shown, a high-performance modified asphalt pavement structure includes, from top to bottom, a 4 cm discontinuous-graded skeleton-dense RMS rubber composite modified asphalt mixture upper layer 1; a non-stick wheel special emulsified asphalt bonding layer 2; a 6 cm continuously-graded suspended dense RMH rubber composite modified asphalt mixture middle layer 3; a modified emulsified asphalt waterproofing layer 4; and an 8 cm continuously-graded suspended dense RMB rubber composite modified asphalt mixture lower layer 5.

[0061] In this embodiment, the raw materials of the upper layer 1 of the RMS rubber composite modified asphalt mixture of the discontinuous gradation skeleton dense type are: RMS rubber composite modified asphalt, basalt coarse aggregate, limestone fine aggregate, and the filler is limestone mineral powder; the raw materials of the middle layer 3 of the RMH rubber composite modified asphalt mixture of the continuous gradation suspension dense type are: RMH rubber composite modified asphalt, limestone coarse aggregate, limestone fine aggregate, and the filler is limestone mineral powder; the raw materials of the lower layer 5 of the continuous gradation suspension dense type RMB rubber composite modified asphalt mixture are: RMB rubber composite modified asphalt, limestone crushed stone coarse aggregate, limestone fine aggregate, and the filler is limestone mineral powder;

[0062] The RMS rubber composite modified asphalt is prepared from the following raw materials, in parts by weight: 10 parts of 40-mesh waste rubber powder, 90 parts of 70# matrix asphalt, 10 parts of diatomaceous earth, 2 parts of SBS, and 2 parts of ferric oxide;

[0063] The preparation method of RMS rubber composite modified asphalt is as follows:

[0064] S1. Preheat the base asphalt at 130°C for 3 hours to make it fluid; then quickly and evenly heat it to 190°C;

[0065] S2. Add SBS to the asphalt heated in step S1, stir for 20 minutes to fully mix with the matrix asphalt, and then shear at 190°C and 8000 r / min for 1.5 hours;

[0066] S3, adding waste rubber powder, diatomaceous earth and ferric oxide to the molten mixture of asphalt and SBS obtained in step S2, and shearing at 190° C. and 2000 r / min for 45 min;

[0067] S4, after the stirring is completed, the mixture is placed in an oven at 160° C. and cured for 2 hours to obtain the RMS rubber composite modified asphalt;

[0068] The RMH rubber composite modified asphalt is prepared from the following raw materials in parts by weight: 30 parts of 40-mesh waste rubber powder, 110 parts of 70# matrix asphalt, 10 parts of diatomaceous earth, 1 part of SBS, and 5 parts of ferric oxide;

[0069] The preparation method of RMH rubber composite modified asphalt is as follows:

[0070] (1) Preheat the base asphalt at 130°C for 3 h to make it fluid; then quickly and evenly heat it to 190°C;

[0071] (2) adding SBS to the asphalt heated in step (1), stirring for 20 minutes to fully mix with the matrix asphalt, and then shearing at 190°C and 8000 r / min for 1.5 hours;

[0072] (3) adding waste rubber powder, diatomaceous earth and ferric oxide to the molten mixture of asphalt and SBS obtained in step (2), and shearing at 190° C. and 2000 r / min for 45 min;

[0073] (4) After the stirring is completed, the mixture is placed in an oven at 160° C. and cured for 2 hours to obtain the RMH rubber composite modified asphalt;

[0074] The RMB rubber composite modified asphalt is prepared from the following raw materials in parts by weight: 40 parts of 40-mesh waste rubber powder, 140 parts of 70# matrix asphalt, 15 parts of diatomaceous earth, 2 parts of SBS, 10 parts of ferric oxide, and 10 parts of cement;

[0075] The preparation method of RMB rubber composite modified asphalt is as follows:

[0076] (1) Preheat the base asphalt at 130°C for 3 h to make it fluid; then quickly and evenly heat it to 190°C;

[0077] (2) adding SBS to the asphalt heated in step (1), stirring for 20 minutes to fully mix with the matrix asphalt, and then shearing at 190°C and 8000 r / min for 1.5 hours;

[0078] (3) adding waste rubber powder, diatomaceous earth, ferric oxide and silicate cement to the molten mixture of asphalt and SBS obtained in step (2), and shearing at 190° C. and 2000 r / min for 45 min;

[0079] (4) After the stirring is completed, the mixture is placed in an oven at 160° C. and cured for 2 hours to obtain the RMB rubber composite modified asphalt;

[0080] The non-stick wheel special emulsified asphalt is prepared from the following raw materials in parts by weight: 50 parts of 70# base asphalt, 3 parts of cetyltrimethylammonium bromide, 1 part of hydroxymethyl cellulose, 2 parts of hydrochloric acid, 4 parts of polyurethane emulsion, and 40 parts of water;

[0081] The preparation method of special emulsified asphalt for non-stick wheels is as follows:

[0082] (1) Dissolve cetyltrimethylammonium bromide, hydroxymethyl cellulose, hydrochloric acid, and polyurethane emulsion in 55°C hot water, stir evenly, and prepare a soap solution;

[0083] (2) Heat the 70# matrix asphalt to 160°C to make it fluid;

[0084] (3) The soap solution prepared in step (1) and the base asphalt in the flowing state in step (2) are mixed, and the mixture is sheared at a high speed by a colloid mill at a rotation speed of 8000 r / min to obtain a special emulsified asphalt for non-stick wheels.

[0085] The modified emulsified asphalt is prepared from the following raw materials in parts by weight: 70 parts of 70# base asphalt, 8 parts of cetyltrimethylammonium bromide, 2 parts of hydroxymethyl cellulose, 50 parts of gray cement, 20 parts of calcium carbonate, 20 parts of wollastonite powder, and 3 parts of polycarboxylic acid water reducer;

[0086] The preparation method of modified emulsified asphalt is as follows:

[0087] Dissolve hexadecyltrimethylammonium bromide and hydroxymethyl cellulose in water, then add flowing 70# matrix asphalt, stir evenly, and then mix with gray cement, calcium carbonate, wollastonite powder, and polycarboxylic acid water reducer.

[0088] In this embodiment, the preparation method of the rubber composite modified asphalt mixture for the upper, middle and lower layers is as follows: the coarse aggregate, fine aggregate and filler are mixed uniformly, heated to a temperature of 180°C, and then the corresponding rubber composite modified asphalt is added and stirred for 3 minutes. In this embodiment, the oil-stone ratio of the upper layer of the discontinuous-graded skeleton-dense RMS rubber composite modified asphalt mixture is 6.4%; the oil-stone ratio of the middle layer of the continuously-graded suspended dense RMH rubber composite modified asphalt mixture is 4.5%; the oil-stone ratio of the lower layer of the continuously-graded suspended dense RMB rubber composite modified asphalt mixture is 4.3%; the spreading rate of the non-stick wheel special emulsified asphalt is controlled to 0.6 kg / m 2 The amount of modified emulsified asphalt spread is controlled at 1.0kg / m 2 The gradation composition of the rubber composite modified asphalt mixture of the upper, middle and lower surface layers is detailed in Table 1.

[0089] Table 1 Gradation composition of rubber composite modified asphalt mixture in upper, middle and lower layers

[0090]

[0091] During construction and paving, the paving temperature of the mixture is 175°C, the initial compaction temperature is 170°C, and the secondary compaction and final compaction temperature shall not be lower than 160°C and 110°C respectively. A double-steel-wheel vibratory roller and a rubber-wheel roller are used for compaction. The compaction process is as follows: 1 steel-wheel static compaction - 3 steel-wheel vibratory compaction - 2 rubber-wheel compaction - 1 steel-wheel static compaction for leveling. The rubber-wheel compaction is used to knead the mixture during the compaction process, so that the compaction layer particles are further evenly compacted without being damaged. The amount of high-viscosity bonding layer applied is controlled at 0.6kg / m 2 ; The amount of waterproof layer sprayed is controlled at 1.0kg / m 2 , and use single-size crushed stone to spread simultaneously, and then use steel wheel roller to compact it to form a waterproof layer structure.

[0092] Example 2

[0093] Except that the RMS rubber composite modified asphalt, RMS rubber composite modified asphalt, and RMS rubber composite modified asphalt raw material composition are different from those in Example 1, everything else is the same as in Example 1;

[0094] Among them, RMS rubber composite modified asphalt is composed of the following raw materials, calculated by weight: 15 parts of waste rubber powder, 100 parts of base asphalt, 15 parts of diatomaceous earth, 3 parts of SBS, and 3 parts of ferric oxide;

[0095] RMH rubber composite modified asphalt is composed of the following raw materials: 40 parts of waste rubber powder, 120 parts of base asphalt, 15 parts of diatomaceous earth, 2 parts of SBS, and 7 parts of ferric oxide;

[0096] RMB rubber composite modified asphalt is composed of the following raw materials: 45 parts of waste rubber powder, 150 parts of base asphalt, 20 parts of diatomaceous earth, 2 parts of SBS, 12 parts of ferric oxide, and 15 parts of cement.

[0097] Comparative Example 1

[0098] This comparative example uses the same mixture gradation as the upper layer described in Example 1, and the raw materials include: Shell SBS modified asphalt, basalt coarse aggregate, limestone fine aggregate, and fillers such as limestone mineral powder and lignin fiber; the PG grade of the Shell SBS (5%) modified asphalt is 76-22, the oil-stone ratio is 6.0%, and the lignin fiber is added at 0.3%.

[0099] Fatigue test

[0100] In order to explore the anti-aging performance of the upper layer of the present invention, a fatigue test was carried out on the rubber composite modified asphalt surface layer structure of Example 1 after long-term aging to compare and analyze the performance effects of the upper layer in Example 1 and Comparative Example 1. The test results are shown in Table 2.

[0101] Table 2 Mixture fatigue test results

[0102]

[0103] Dynamic modulus test

[0104] In order to explore the durability of the upper layer of the present invention, a dynamic modulus test was carried out on the rubber composite modified asphalt surface layer structure of Example 1 after long-term aging to compare and analyze the performance effects of the upper layer in Example 1 and Comparative Example 1. The test results are shown in Table 3.

[0105] Table 3 Mixture dynamic modulus test results

[0106]

[0107] As shown in Table 2 and Table 3, the comparison results of the upper layer in Example 1 and Comparative Example 1 show that:

[0108] (1) When the strain levels are 400με, 600με, and 800με, respectively, the fatigue life of the RMS rubber composite modified asphalt mixture after long-term aging is 1.93, 1.61, and 2.26 times that of the SBS modified asphalt mixture, and the fatigue life improvement effect is significant;

[0109] (2) Under low temperature conditions, the dynamic moduli of the two mixtures are relatively close. As the temperature increases and the frequency decreases, the ratio between the two gradually increases. At 30°C (0.1Hz), the dynamic modulus of the RMS rubber composite modified asphalt mixture is more than 1.9 times that of the SBS modified asphalt mixture.

[0110] Comparative Example 2

[0111] This comparative example uses the same mixture gradation as the middle surface layer described in Example 1, and the raw materials include: Shell SBS modified asphalt, limestone crushed stone coarse aggregate, limestone fine aggregate, and limestone mineral powder as filler; the PG grade of Shell SBS (5%) modified asphalt is 76-22, and the oil-stone ratio is 4.2%.

[0112] Hamburg rutting test

[0113] In order to explore the high-temperature rutting resistance of the middle surface layer of the present invention, a hamburger rutting test was performed on the rubber composite modified asphalt surface layer structure of Example 1 to compare and analyze the performance effects of the middle surface layer in Example 1 and Comparative Example 2. The test results are shown in Table 4.

[0114] Table 4 Mixture Hamburger rutting test results

[0115]

[0116]

[0117] As can be seen from Table 4, the use of RMH rubber composite modified asphalt can significantly reduce the rutting depth level of the mixture; under the conditions of the immersed steel wheel combination, the rutting depth ratio of the two is 0.27 at 60°C, that is, the use of RMH rubber composite modified asphalt can reduce the rutting depth by 73%; at 70°C, when the number of loading times reaches 13,200, the rutting deformation of the SBS modified asphalt mixture exceeds 25 mm, reaching the deformation limit of the Hamburg rutting test, which shows that the high-temperature rutting resistance of the middle surface layer in Example 1 is better than that of the mixture described in Comparative Example 2.

[0118] Comparative Example 3

[0119] This comparative example uses the same mixture gradation as the lower layer described in Example 1, and the raw materials include: 70# matrix asphalt, limestone crushed stone coarse aggregate, limestone fine aggregate, and limestone mineral powder as filler; the PG grade of 70# matrix asphalt is 64-16, and the oil-stone ratio is 3.9%.

[0120] Fatigue test

[0121] In order to explore the fatigue crack resistance of the lower layer of the present invention, a fatigue test was carried out on the rubber composite modified asphalt surface layer structure of Example 1 to compare and analyze the performance effects of the lower layer in Example 1 and Comparative Example 3. The test results are shown in Table 5.

[0122] Table 5 Mixture fatigue test results

[0123]

[0124] As can be seen from Table 5, compared with Comparative Example 3, at a strain level of 200 με, the fatigue life of the RMB rubber composite modified asphalt mixture of the present invention at 50% stiffness modulus is 2.659 million times, which is 3.88 times the fatigue life of the 70# matrix asphalt mixture. This shows that the fatigue cracking resistance of the lower layer of the RMB rubber composite modified asphalt of the present invention far exceeds that of Comparative Example 3.

[0125] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-performance modified asphalt surface structure, characterized in that: The invention comprises, from top to bottom, a discontinuously graded skeleton dense type RMS rubber composite modified asphalt mixture upper layer (1), a non-stick wheel special emulsified asphalt bonding layer (2), a continuously graded suspended dense type RMH rubber composite modified asphalt mixture middle layer (3), a modified emulsified asphalt waterproof layer (4), and a continuously graded suspended dense type RMB rubber composite modified asphalt mixture lower layer (5); wherein, in parts by weight, the RMS rubber composite modified asphalt is prepared from the following raw materials: 5-20 parts of waste rubber powder, 90-100 parts of matrix asphalt, 5-15 parts of diatomaceous earth, 1-4 parts of SBS, and 0.5-5 parts of ferric oxide; The RMH rubber composite modified asphalt is prepared from the following raw materials, in parts by weight: 20-40 parts of waste rubber powder, 100-120 parts of matrix asphalt, 1-10 parts of diatomaceous earth, 1-2 parts of SBS, and 1-10 parts of ferric oxide; The RMB rubber composite modified asphalt is prepared from the following raw materials, in parts by weight: 25-45 parts of waste rubber powder, 120-150 parts of matrix asphalt, 1-20 parts of diatomaceous earth, 1-3 parts of SBS, 1-20 parts of ferric oxide, and 1-15 parts of cement.

2. A high performance modified asphalt surface structure according to claim 1, characterized in that: The preparation method of RMS rubber composite modified asphalt is as follows: S1. Preheat the base asphalt at 120-150°C for 1-3 hours to make it fluid; then heat it to 180-200°C; S2. Add SBS to the asphalt heated in step S1, stir for 10-30 minutes to fully mix with the matrix asphalt, and then shear at 180-200°C and 6000-8000 r / min for 0.5-1.5 hours; S3, adding waste rubber powder, diatomaceous earth and ferric oxide to the molten mixture of asphalt and SBS obtained in step S2, and shearing at 180-200° C. and 2000-4000 r / min for 0.5-1 h; S4. After the shearing is completed, the asphalt is placed in an oven at 150-180° C. for curing for 1-3 hours to obtain the RMS rubber composite modified asphalt.

3. A high performance modified asphalt surface structure according to claim 1, characterized in that: The oil-stone ratio of the RMS rubber composite modified asphalt mixture is 6.2-6.6%; the oil-stone ratio of the RMH rubber composite modified asphalt mixture is 4.4-4.6%; and the oil-stone ratio of the RMB rubber composite modified asphalt mixture is 4.2-4.4%.

4. A high performance modified asphalt surface structure according to claim 1, characterized in that: The aggregate used in the top layer (1) of the gap-graded skeleton dense RMS rubber composite modified asphalt mixture has a critical sieve aperture of 13.2 mm with a passing rate of 90% to 94%, a sieve aperture of 4.75 mm with a passing rate of 20% to 30%, and a sieve aperture of 0.075 mm with a passing rate of 8% to 10%; The aggregate used in the middle surface layer (3) of the continuous graded suspended dense RMH rubber composite modified asphalt mixture has a critical sieve aperture of 19 mm with a pass rate of 92% to 98%, a sieve aperture of 4.75 mm with a pass rate of 25% to 35%, and a sieve aperture of 0.075 mm with a pass rate of 4% to 7%; The aggregate used in the lower layer (5) of the continuously graded suspended dense RMB rubber composite modified asphalt mixture has a critical sieve aperture of 26.5 mm with a pass rate of 92% to 96%, a sieve aperture of 4.75 mm with a pass rate of 22% to 30%, and a sieve aperture of 0.075 mm with a pass rate of 3% to 6%.

5. A high performance modified asphalt surface structure according to claim 4, characterized in that: The thickness of the upper layer (1) of the discontinuous-graded skeleton-dense rubber composite modified asphalt mixture is 3.5-4.5 cm; the thickness of the middle layer (3) of the continuously-graded suspended-dense rubber composite modified asphalt mixture is 5.5-6.5 cm; and the thickness of the lower layer (5) of the continuously-graded suspended-dense rubber composite modified asphalt mixture is 7.5-8.5 cm.

6. The high performance modified asphalt surface structure according to claim 1, characterized in that: The non-stick wheel special emulsified asphalt is prepared from the following raw materials in parts by weight: 45-65 parts of base asphalt, 1-5 parts of emulsifier, 0.1-3 parts of stabilizer, 0.5-3 parts of pH regulator, 0.5-5 parts of polymer modifier, and 40-50 parts of water.

7. The high performance modified asphalt surface structure according to claim 1, characterized in that: The modified emulsified asphalt is prepared from the following raw materials in parts by weight: 50-70 parts of base asphalt, 3-10 parts of emulsifier, 1-3 parts of stabilizer, 40-60 parts of cement, 40-55 parts of filler, and 1-5 parts of additive.

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