A multi-point contact thin layer noise reduction rubber modified asphalt concrete overlay structure and a preparation method thereof

Abstract

The application provides a multi-point contact type thin-layer noise reduction rubber modified asphalt concrete overlay structure and a preparation method thereof. 2 The waterproof bonding layer is laid on the original road surface. The high rubber content asphalt is added to improve the anti-skid performance and noise reduction performance of the thin-layer overlay, and the water-based epoxy emulsified asphalt is used to enhance the interlayer bonding strength and the anti-fatigue performance of the overlay.

Description

TECHNICAL FIELD

[0001] The present application relates to a multi-point contact type thin-layer noise-reducing rubber modified asphalt concrete overlay material and a preparation method thereof, and belongs to the field of road engineering. BACKGROUND

[0002] In recent years, with the development of urban and rural economic construction, the use frequency of road traffic continues to increase, and some problems have gradually emerged. The proportion of road sections that have been open to traffic for more than ten years exceeds 60%, and the road industry in China has changed from the construction stage to the combination of construction and maintenance stage. With the increase of road service life, more and more road diseases appear. At present, the proportion of highway sections with transverse force coefficient SFC less than 48 in some areas exceeds 20%, and the decline of skid resistance performance has become one of the main problems faced by highways.

[0003] Thin-layer overlay technology, as a preventive maintenance technology for asphalt pavement, can effectively improve the flatness, safety and comfort of the original pavement. The commonly used hot-mix thin-layer overlay technology includes micro-surfacing, Novachip, SMA, AC, etc. However, these thin-layer overlay technologies have defects such as high noise and poor durability in the design and construction process [Yu Jiangmiao, Yang Nikun, Yu Huayang. Research and application status of road high-performance asphalt ultra-thin wearing layer technology [J]. Journal of Central South University (Natural Science Edition), 2021. Li Ning. Research and application overview of typical preventive maintenance measures for pavement [J]. Highway, 2021, 66(6):4]. In addition, the bonding ability between the thin-layer overlay and the original pavement is still an important factor to ensure the development of this technology. After using the overlay paving material in domestic engineering, diseases such as aggregate spalling, voiding and even delamination often occur [Guo Yinchuan, Shen Aiqin, Zhang Jinrong, et al. Mechanical response and shear strength test of asphalt pavement under seal coat [J]. China Journal of Highway, 2010(04):20-26]. Thin-layer overlay technology has not yet formed a functional-performance balanced pavement structure design theory and method. SUMMARY

[0004] The purpose of the present application is to provide a multi-point contact type thin-layer noise-reducing rubber modified asphalt concrete overlay structure and a preparation method thereof. The concrete overlay adopts a skeleton dense structure, and uses high-content rubber modified asphalt to fill the gaps between aggregates, thereby increasing its noise reduction performance. The use of water-based epoxy emulsified asphalt effectively improves the interlayer bonding strength and fatigue resistance of the thin-layer overlay.

[0005] In order to achieve the above-mentioned application purposes, the present application adopts the following technical solutions:

[0006] A multi-point contact thin layer noise reduction rubber modified asphalt concrete overlay structure, which is a two-layer structure. The upper layer is a multi-point contact high-content rubber modified asphalt concrete layer with a paving thickness of 1.5-2cm; the lower layer is a waterproof bonding layer made of water-based epoxy emulsified asphalt with a dosage of 0.4-0.7kg / m 2 The use of water-based epoxy emulsified asphalt as the waterproof bonding layer material is to ensure that the multi-point contact high-content rubber-modified asphalt concrete can be effectively combined with the original pavement.

[0007] The preparation method of the above-mentioned multi-point contact thin layer noise reduction rubber modified asphalt concrete overlay structure is as follows:

[0008] Step ①: Preparation of waterborne epoxy emulsified asphalt;

[0009] Step ②: Multi-point contact high-content rubber-modified asphalt concrete gradation design;

[0010] Step 3: Laying of the overlay structure: First, lay water-based epoxy emulsified asphalt on the original road surface as a waterproof bonding layer, with a dosage of 0.4-0.7kg / m 2 ; Then lay a modified asphalt concrete layer on the waterproof bonding layer with a paving thickness of 1.5-2cm.

[0011] The upper layer multi-point contact high-content rubber modified asphalt concrete includes the following components in parts by weight:

[0012] Aggregate: 100 parts;

[0013] Mineral powder: 5-10 parts;

[0014] High-content rubber asphalt: 10-12 parts, preferably 11 parts;

[0015] Basalt fiber: 0.1-0.5 parts;

[0016] The maximum nominal particle size of the aggregate is 9.5 mm.

[0017] The basalt fiber has a density of 2.656 g / cm 3 , fiber length is 5-10mm, tensile strength is >2500MPa, and elastic modulus is 90GPa.

[0018] The high-content rubber-modified asphalt is composed of the following components in the following weight ratios:

[0019] Base asphalt: 100 parts;

[0020] Rubber powder: 20.0-40.0% by weight of base asphalt;

[0021] Pyrolysis oil: 5.0-10.0% by weight of base asphalt;

[0022] Stabilizer: 0.1-0.3% by weight of base asphalt;

[0023] Viscosity reducer: 1.0-2.0% by weight of base asphalt.

[0024] The multi-point contact type high-content rubber modified asphalt concrete has the gradation range shown in Table 1:

[0025] Table 1 Multi-point contact type high-content rubber modified asphalt concrete

[0026] Mesh size (mm) 9.5 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Pass rate (%) 100 36-82 15-62 5-50 3-37 2-22 1-13 0-8

[0027] The multi-point contact type high-content rubber modified asphalt concrete is prepared according to the Technical Specification for Construction of Highway Asphalt Pavement (JTG F40-2004), has a target air void of 3.0-5.5%, and has a rubber content of 1.0-4.0% of the mass of aggregate, and has a skeleton filling coefficient k≥0.60.

[0028] The water-based epoxy emulsified asphalt used in the lower structure contains the following components: base asphalt: epoxy resin: emulsifier: modifier styrene-butadiene copolymer: stabilizer = 100: 8.0: 0.4: 4.0: 0.25.

[0029] The preparation method of the water-based epoxy emulsified asphalt has the following steps:

[0030] Step 1: Add the modifier to the base asphalt to prepare the modified asphalt;

[0031] Step 2: Weigh the emulsifier and the stabilizer, add hot water to prepare the soap solution, add hydrochloric acid to adjust the pH of the soap solution, and keep warm for standby;

[0032] Step 3: Emulsification process: Preheat the colloid mill and pour the prepared soap solution into the colloid mill. Start the colloid mill and make the emulsion fully stirred under the stirring of the colloid mill. The stirring time is controlled within 30s. Pour the hot modified asphalt into the soap solution and assist the stirring with a glass rod. The emulsification time is 1-3min. The emulsified asphalt emulsion is brownish red, fine and uniform, and has no lumping phenomenon.

[0033] Beneficial effects

[0034] (1) In the cover structure, the multi-point contact type high-content rubber modified asphalt concrete used in the upper layer has a maximum nominal particle size of 9.5mm of aggregate, and the best asphalt content is determined according to the Technical Specification for Construction of Highway Asphalt Pavement (JTG F40-2004) to prepare the asphalt concrete. The target air void is 3.0-5.5%.

[0035] (2) The multi-point contact type thin layer noise reduction rubber modified asphalt concrete overlay provided by the application improves the anti-skid performance and noise reduction performance of the thin layer overlay by adding high content rubber asphalt (the rubber content can reach 1.0-4.0% of the mass of the aggregate), and the interlayer bonding strength and the anti-fatigue performance of the overlay are enhanced by using water-based epoxy emulsified asphalt. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 A multi-point contact type thin layer noise reduction rubber modified asphalt concrete overlay structure according to the application; 1 - original pavement, 2 - waterproof bonding layer, 3 - modified asphalt concrete layer, 4 - rubber particles, 5 - aggregate;

[0037] Figure 2 Fatigue anti-cracking performance of different types of asphalt concrete;

[0038] Figure 3 Noise comparison of the multi-point contact type thin layer noise reduction rubber modified asphalt concrete overlay and the original pavement. DETAILED DESCRIPTION

[0039] The content of the application will be further described below in combination with the drawings and specific examples, but the content of the application is not limited to the examples only. It should be understood that the specific examples described herein are only used to explain the application and are not used to limit the application. After reading the application, those skilled in the art can make various equivalent modifications of the application, which fall within the scope defined by the claims attached hereto.

[0040] Example 1: Multi-point contact type thin layer noise reduction rubber modified asphalt concrete overlay structure and its preparation method

[0041] (1) The materials used in the upper layer (multi-point contact type high content rubber modified asphalt concrete layer) of the overlay structure are shown in Table 2. The components of the high content rubber asphalt in Table 2 are as follows: base asphalt : rubber powder : pyrolysis oil : stabilizing agent : viscosity reducer = 100 : 25 : 10 : 0.2 : 2.

[0042] Table 2: Raw material ratio of the upper layer material sample of the overlay structure

[0043] No. Sample 1 Sample 2 Sample 3 Aggregate 100 parts 100 parts 100 parts Mineral powder 7 7 8 Rubber asphalt content 10.5 11 12 Basalt fiber 0.2 0.4 0.5

[0044] (2) The material used in the lower layer of the overlay structure is water-based epoxy emulsified asphalt, and the components are as follows: base asphalt : epoxy resin : emulsifier : curing agent (styrene-butadiene copolymer) : stabilizing agent = 100 : 8.0 : 0.4 : 4.0 : 0.25. The specific steps of the preparation method are as follows:

[0045] Step 1: Preparation of modified asphalt: Put base asphalt into an oven and heat to 150-160℃, add styrene-butadiene copolymer, stir for 40 min, then raise the temperature to 170-180℃, open the shearing machine and shear for 40 min, control the asphalt temperature at 175±3℃, not exceeding 180℃;

[0046] Step 2: Preparation of soap solution. Weigh the emulsifier and stabilizer, add hot water, adjust the pH to about 2.5 with hydrochloric acid, obtain the soap solution, then put it into a 70℃ incubator for standby;

[0047] Step 3: Preheat the colloid mill. Pour water heated to about 70℃ into the colloid mill, start the emulsifier, and preheat the inside of the machine;

[0048] Step 4: Pour the soap solution prepared in Step 2 into the preheated colloid mill, start the colloid mill, mix thoroughly, and control the stirring time within 30s to prevent the temperature of the soap solution from dropping too much due to prolonged stirring;

[0049] Step 5: Pour the hot asphalt obtained in Step 1 into the soap solution in Step 4. Do not pour all at once, control the flow, and add slowly and uniformly. Stir with a glass rod while adding asphalt to timely eliminate the generated bubbles;

[0050] Step 6: The emulsification time is 1-3 min. If the time is too short, it is not enough for full emulsification; if the time is too long, it does not significantly improve the emulsification effect, and energy is wasted. The emulsified asphalt emulsion should be brownish, fine and uniform, without clumping or caking.

[0051] (3) A method for preparing a multi-point contact type thin-layer noise reduction rubber modified asphalt concrete overlay structure, the steps are as follows:

[0052] Step 1: Preparation of water-based epoxy emulsified asphalt;

[0053] Step 2: Multi-point contact type high-content rubber modified asphalt concrete gradation design. The gradation used in the examples is shown in Table 3.

[0054] Table 3 Gradation used in the test

[0055] Mesh size (mm) 9.5 4.75 2.36 1.18 0.6 0.3 0.15 0.075 Pass rate (%) 100 41 22 11 6 4 3 2

[0056] A multi-point contact type high-content rubber modified asphalt concrete was designed by the Marshall design method. The Marshall test piece indexes of different rubber modified asphalt (high-content rubber asphalt) contents are shown in Table 4. The rubber modified asphalt content is finally determined to be 11.0%.

[0057] Table 4 Marshall test piece indexes of different rubber modified asphalt contents

[0058]

[0059] In order to verify the skeleton state of the multi-point contact type high-dosage rubber modified asphalt concrete, the skeleton filling coefficients of the multi-point contact type high-dosage rubber modified asphalt concrete and the SMA asphalt concrete with the same skeleton dense structure were compared, as shown in Table 5. It can be seen that the skeleton filling coefficient of the multi-point contact type high-dosage rubber modified asphalt concrete (sample 2) is larger than that of the SMA-10, indicating that the contact points of the coarse aggregate are more and the embedded state is better.

[0060] Table 5 Skeleton filling coefficients of different suspension dense type asphalt concretes

[0061]

[0062]

[0063] The skeleton filling coefficient k is greater than or equal to 0.60, wherein the skeleton filling coefficient k can be obtained by formula 1.

[0064]

[0065] In formula 1, ρ f is the bulk volume relative density of the mixture sample; ρ ca is the average bulk volume relative density of the coarse aggregate; m ca is the mass of the coarse aggregate in the sample; m tot is the total mass of the sample.

[0066] Step 3: Laying of the overlay structure

[0067] First, water-based epoxy emulsified asphalt is laid on the original pavement 1 as a waterproof bonding layer 2, and the amount is 0.4-0.7 kg / m 2 ; then the modified asphalt concrete layer 3 is laid on the waterproof bonding layer, and the laying thickness is 1.5-2 cm, and the obtained overlay structure is shown in Figure 1 .

[0068] Example 2: Performance verification

[0069] (1) Anti-skid performance

[0070] The initial anti-skid performance comparison of the multi-point contact type thin-layer noise-reducing rubber modified asphalt concrete overlay, the SMA-10 and the AC-10 asphalt concrete overlays is shown in Table 6.

[0071] Table 6 Comparison of initial anti-skid performance of different types of asphalt concrete overlays

[0072]

[0073] From Table 6, it can be seen that the initial skid resistance of the multi-point contact thin layer noise reduction rubber modified asphalt concrete overlay is similar to that of SMA-10 and is better than that of AC-10 mixture.

[0074] (2) Anti-fatigue performance research

[0075] The fatigue times of the multi-point contact thin layer noise reduction rubber modified asphalt concrete overlay under different strains are compared with those of SMA-10 and AC-10, and the results are shown in Figure 2

[0076] It can be seen that the fatigue performance of the multi-point contact thin layer noise reduction rubber modified asphalt concrete overlay (sample 2) is higher than that of SMA-10 and AC-10 concrete overlays under each strain level, especially under high strain level. This shows that the application of water-based epoxy emulsified asphalt enables the multi-point contact thin layer noise reduction rubber modified asphalt concrete overlay to have good anti-fatigue ability.

[0077] (3) Field noise detection

[0078] The noise of the multi-point contact thin layer noise reduction rubber modified asphalt concrete overlay under different vehicle speeds and strains is compared with that of the original road, as shown in Figure 3 It can be seen that the multi-point contact thin layer noise reduction rubber modified asphalt concrete overlay can reduce about 2-3 decibels compared with the original road. This is mainly because the use of high-content rubber asphalt improves the elastic properties of asphalt compared with base asphalt, achieves the effect of buffering noise, and reduces noise.

[0079] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the technical field, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.​

Claims

1. A multi-point contact thin-layer noise reduction rubber-modified asphalt concrete overlay structure, characterized by: It has a two-layer structure. The upper layer is a multi-point contact high-content rubber-modified asphalt concrete layer with a paving thickness of 1.5-2cm; the lower layer is a waterproof bonding layer made of water-based epoxy emulsified asphalt with a dosage of 0.4-0.7kg / m 2 , the waterproof bonding layer is laid on the original road surface; The upper layer material is multi-point contact type high-content rubber modified asphalt concrete, and its components, calculated by weight, include the following components: aggregate: 100 parts; mineral powder: 5-10 parts; High content rubber modified asphalt: 10-12 parts; Basalt fiber: 0.1-0.5 parts; The high-content rubber-modified asphalt contains the following components in weight ratios: base asphalt, rubber powder accounting for 20.0-40.0% of the base asphalt weight ratio, pyrolysis oil accounting for 5.0-10.0% of the base asphalt weight ratio, stabilizer accounting for 0.1-0.3% of the base asphalt weight ratio, and viscosity reducer accounting for 1.0-2.0% of the base asphalt weight ratio; the basalt fiber has a density of 2.656 g / cm 3 , fiber length is 5-10mm, tensile strength is >2500MPa, elastic modulus is 90GPa; The lower layer material is water-based epoxy emulsified asphalt, and its components are as follows: Base asphalt: Epoxy resin: emulsifier: curing agent: stabilizer = 100: 8.0: 0.4: 4.0: 0.25; the curing agent is styrene-butadiene copolymer.

2. The multi-point contact thin layer noise reduction rubber modified asphalt concrete overlay structure according to claim 1 is characterized by: The gradation range of the mixture is as follows: 。 3. The multi-point contact thin layer noise reduction rubber modified asphalt concrete overlay structure according to claim 1 is characterized by: The preparation method of waterborne epoxy emulsified asphalt is as follows: Step ①: preparing modified asphalt; heating the base asphalt to 150°C~160°C, adding a curing agent styrene-butadiene copolymer, stirring to swell, heating to 170~180°C, and shearing with a shearing machine for 40 minutes to obtain the modified asphalt, which is set aside; Step ②: Prepare soap solution; weigh emulsifier and stabilizer, add hot water, and adjust the pH to 2.5 with hydrochloric acid to obtain soap solution, keep warm, and set aside; Step 3: Pour the soap solution prepared in step 2 into the preheated colloid mill, start the colloid mill, and stir thoroughly. The stirring time should be controlled within 30 seconds. Step ④: Under stirring conditions, slowly and evenly inject the hot modified asphalt from step ① into the soap solution from step ③ in batches and emulsify for 1 to 3 minutes to obtain a brown asphalt emulsion with fine and uniform particles and no agglomeration.

4. The method for preparing a multi-point contact thin layer noise reduction rubber modified asphalt concrete overlay structure according to claim 1, characterized in that: Here are the steps: Step ①: Preparation of waterborne epoxy emulsified asphalt; Step ②: Multi-point contact high-content rubber-modified asphalt concrete gradation design; Step 3: Laying of the overlay structure: First, lay water-based epoxy emulsified asphalt on the original road surface as a waterproof bonding layer, with a dosage of 0.4-0.7kg / m 2 ; Then lay a modified asphalt concrete layer on the waterproof bonding layer with a paving thickness of 1.5-2cm.

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