Preparation method and construction process of anti-leakage asphalt pavement material

Abstract

The invention relates to a preparation method and a construction process of an anti-leakage asphalt pavement material adopting sandstone aggregate, the optimized sandstone aggregate is added into molten asphalt, and the sandstone aggregate forms a specific angle in a vibrating screen by controlling the vibration frequency and amplitude. Test results show that the method can reduce the aggregate cost by 20% or more, and the asphalt pavement material adopting the sandstone aggregate has excellent performance in the aspects of leakage performance, crack resistance and cost effectiveness, is suitable for high-temperature, high-humidity and heavy traffic environments, and provides technical support for efficient utilization of sandstone resources and construction of durable pavements.

Description

Technical Field

[0001] The present invention relates to the field of building materials, and specifically relates to a preparation method and a construction process of a leak-proof asphalt pavement material using aggregates such as sandstone, which are applicable to the construction of high-grade highways in high-temperature, high-humidity, and rainy areas. Background Art

[0002] Asphalt pavement is one of the commonly used pavement structures in highway construction. However, due to its own properties, it is easily affected by environmental factors, resulting in problems such as pavement leakage and cracking, which affect the service life and safety of the road. Therefore, studying a leak-proof asphalt pavement material is of great significance for highway construction.

[0003] Currently, some studies have proposed leak-proof asphalt pavement materials, such as methods of adding waterproof agents and polymer modification. However, these methods have certain deficiencies, such as the low durability of waterproof agents and the high cost of polymer modification.

[0004] Sandstone is a natural sedimentary rock, which is widely distributed and has a rich reserve in Guangxi and its surrounding areas. It is easy to mine and has rich pore structures, low density, and multi-angle particle distribution characteristics. However, traditional asphalt pavements mostly use limestone and basalt aggregates. Due to the lack of limestone and basalt aggregates, long-distance transportation in areas where sandstone is distributed in actual projects results in high costs and large carbon emissions. Although sandstone has high hardness, is dense, and has good wear resistance, due to the large difference in surface roughness, it is easy to cause uneven asphalt wrapping, which limits its application. Therefore, when using sandstone, sandstone with qualified compressive strength and crushing value is required.

[0005] CN102153926A discloses an asphalt pavement leakage regeneration coating and its preparation method belonging to the technical field of the preparation of asphalt pavement preventive maintenance materials. The regeneration coating is a liquid mixture at room temperature, and its specific composition is: 30-50 parts by weight of film-forming resin, 3-9 parts by weight of leakage agent, 2-8 parts by weight of asphalt regenerant, 30-50 parts by weight of solvent, and 10-20 parts by weight of coal tar. The asphalt pavement leakage regeneration coating prepared by this invention can strongly penetrate the asphalt pavement, deeply restore the aged asphalt, form a new protective layer, and does not require a mixture overlay on the original pavement. Only by restoring the activity of the aged asphalt can the pavement restore its service function; at the same time, it can form a sealing film on the asphalt pavement to prevent water, gasoline, chemicals, etc. from invading the asphalt pavement.

[0006] CN110003667A discloses a water-resistant modifier for asphalt, belonging to the technical field of road engineering construction. In the present invention, sodium-based bentonite with strong water absorption and swelling force and hard nano-SiO2 components are used to block the pores between the internal components of asphalt, achieving the purpose of stopping water with water, and improving the water resistance of asphalt. The added polylactic acid component has high compatibility, enhancing the mechanical properties of the water-blocking structure and further improving the water resistance effect of asphalt. The cross-linking agent is beneficial to the stable dispersion of the natural latex component with good water resistance in the three-dimensional cross-linked network void structure, improving the mechanical properties inside the asphalt. The silanol groups and hydroxyl groups present on the surface of silica sol can undergo dehydration or de-alcoholization reactions with the alkyl groups on the silane, forming a Si-O-Si waterproof layer on the surface and inside of the concrete, effectively preventing the leakage and movement of water inside it and improving the water resistance of asphalt.

[0007] CN101259995A discloses a waterproof asphalt mixture for the surface layer of a subgrade, mainly used for the surface layer of the subgrade of a ballastless track railway, and can also be used for the waterproof treatment of other field floors that do not bear loads. The leakage coefficient K of this mixture is < 10×10 －4 cm / s, the void ratio VV is 1% - 3%, the standard Marshall stability MS > 5 kN, and the freeze-thaw splitting strength ratio TSR > 60%. This invention has good waterproof performance, can prevent surface water from seeping down, is used in the road surface structure, can protect the subgrade bed soil from water erosion, and its ultimate effect is to maintain the long-term stability of the dynamic performance of the subgrade bed, ensuring the comfort, safety and reliability of high-speed driving.

[0008] CN110016293A provides a leaky rubber asphalt waterproof coating and its preparation method. The waterproof coating is composed of the following components in parts by mass: 10 - 30 parts of chloroprene rubber, 50 - 70 parts of anionic emulsified asphalt, 20 - 30 parts of styrene-acrylic emulsion, 10 - 20 parts of a modifying agent, 3 - 10 parts of a thickener, 5 - 20 parts of a terpene tackifying resin, and 1 - 5 parts of a cement-based leaky crystallization masterbatch. The preparation method is as follows: at room temperature, the anionic emulsified asphalt emulsion is added to the chloroprene rubber, and after stirring thoroughly for 20 - 40 minutes, the modifying agent is added while stirring, for 15 - 30 minutes; then the styrene-acrylic emulsion is added, and after stirring thoroughly for 20 - 30 minutes, the thickener is added while stirring, for 20 - 30 minutes; then the cement-based leaky crystallization masterbatch is added while stirring, for 15 - 25 minutes; finally, the terpene tackifying resin and the thickener are added and stirred thoroughly for 20 - 30 minutes. The coating has excellent waterproofness, high elongation, high bond strength, good film-forming property, strong self-healing ability, and puncture resistance.

[0009] Although there are studies on anti-leakage asphalt pavement materials and related materials in the existing technology, there are still problems and deficiencies, such as complex binder modification processes, cumbersome modification processes for asphalt pavement materials, and poor anti-leakage performance. Therefore, there is an urgent need to provide a technology with a simple process and outstanding modification effects to prepare anti-leakage asphalt pavement materials. Summary of the Invention

[0010] The present invention aims to provide a new method for preparing anti-leakage asphalt pavement materials using sandstone aggregates and its construction process. The method is simple, low-cost, and can effectively improve the anti-leakage performance of the pavement.

[0011] In view of the disadvantages of complex modification technology and insufficient anti-leakage performance in the existing technology, the inventor has significantly improved the anti-leakage performance of asphalt pavement materials by selecting and optimizing the angularity of sandstone aggregates. The inventor found through experiments that the angularity of sandstone aggregates is a crucial factor affecting the pore structure and leakage performance of asphalt pavement materials. In traditional asphalt pavement materials, in order to increase the wrapping and viscosity between aggregates and asphalt binder, the aggregates are usually in a round or nearly round shape. Some problems will occur during the preparation process of this shape of aggregates. For example, the gaps left between round aggregates are relatively large, making the asphalt pavement materials prone to leakage, thus resulting in a decline in waterproof performance. And overly sharp aggregates will affect the adhesion performance of asphalt: for example, the surface roughness of sharp aggregates is relatively high, and the contact area with asphalt is relatively small, which is not conducive to the adhesion between asphalt materials and aggregates, thus affecting the stability and service life of pavement materials. At the same time, too high an angularity of aggregates will affect the anti-cracking performance of asphalt pavement materials: the sharp surface of aggregates is easy to form stress concentration points in asphalt pavement materials, accelerating the cracking and splitting of asphalt pavement materials, thus affecting the anti-cracking performance of pavement materials.

[0012] The inventor improves the tight fit and full filling between aggregates and reduces the gaps between aggregates by selecting and optimizing the angularity of aggregates, thereby improving the waterproof and anti-leakage performance of asphalt pavement materials. Specifically, when the angularity of aggregates increases, the convex and concave parts between aggregates will increase, which can increase the friction between aggregates and make the aggregates fit more closely.

[0013] Therefore, the present invention proposes to use sandstone as the core aggregate, taking advantage of its characteristic of a relatively high proportion of particles with an angle of 20 - 30 degrees formed naturally (about 50 - 65% of the total), and further optimizing the angle distribution through vibration screening to reduce the cost of manual screening. The angular structure of sandstone particles can enhance the interlocking effect between aggregates, reduce the void ratio, and thus improve the anti-leakage performance. In addition, the low thermal conductivity characteristic of sandstone can reduce the thermal expansion and contraction of asphalt materials and extend the pavement life. In practical applications, the angle of aggregates can be adjusted to achieve the best effect through reasonable aggregate screening and screen design.

[0014] Compared with the complexity and inoperability of the modification processes for the complex compound structures of a large number of adhesives or asphalt binders in the prior art, the technical solution of the present invention specifically selects and regulates the angular range and proportion of the aggregates to achieve the effect of improving the anti-leakage property of the asphalt material.

[0015] One aspect of the present invention provides a method for preparing an anti-leakage asphalt pavement material.

[0016] Its raw materials include asphalt binder, sandstone aggregate, filler, polymer, etc.

[0017] The specific steps of its preparation include:

[0018] 1) Prepare an anti-leakage asphalt binder:

[0019] Using asphalt binder as the main raw material, adding polymer to the asphalt binder and mixing them to obtain an anti-leakage asphalt mixture. The asphalt binder and the polymer are mixed at a temperature of 160 - 180°C for 30 - 40 minutes;

[0020] 2) Prepare the anti-leakage asphalt pavement material:

[0021] The anti-leakage asphalt binder obtained in step 1) is mixed with sandstone aggregate and filler to obtain an anti-leakage asphalt pavement material; among them, when mixing the aggregate, it is added to the molten asphalt mixture, stirred evenly with a mixer, and then put into a vibrating screen for screening. By controlling the vibration frequency and amplitude, a specific angular distribution is formed.

[0022] In some embodiments, the polymer contains a modifier, and the modifier is selected from one or a combination of SBS, SBR, and EVA.

[0023] In some embodiments, the weight part ratio of the asphalt binder to the polymer is: 80 - 90:10 - 20:.

[0024] In some embodiments, the aggregate is selected from one or a combination of sandstone, limestone, granite, basalt, and pebble.

[0025] In some embodiments, the filler is selected from one or a combination of slaked lime and cement.

[0026] In some embodiments, in step 2), the proportion of the angular distribution of the sandstone aggregate between 20 and 30 degrees is 45 - 68%.

[0027] In some embodiments, in step 2), the above components are mixed and stirred at a temperature of 150 - 170°C for 20 - 30 minutes to obtain an anti-leakage asphalt pavement material.

[0028] In some embodiments, in step 2), the weight ratio of the leak-proof asphalt binder, sandstone aggregate, and filler is 5-10:80-90:5-10.

[0029] The present invention also provides a construction process for a leak-proof asphalt pavement material, comprising the following steps:

[0030] 1) Pavement treatment:

[0031] Before the construction of the leak-proof asphalt pavement material, the pavement is treated to remove debris, dust, and other impurities, and the damaged parts are repaired;

[0032] 2) Primer spraying:

[0033] A primer is sprayed on the pavement to improve the adhesion between the pavement and the leak-proof asphalt pavement material; the primer preferably contains a tackifier;

[0034] 3) Laying the leak-proof asphalt pavement material:

[0035] Construct according to the "graded gravel cushion - sandstone water-stable base - asphalt surface course" structure, lay the obtained leak-proof asphalt pavement material on the pavement and compact it to form a leak-proof asphalt pavement;

[0036] In some embodiments, in step 2), the tackifier includes SBS.

[0037] In some embodiments, in step 3), the construction temperature is 120-140°C, and the compaction temperature is 120-130°C.

[0038] In some embodiments, in step 3), the compaction method can be selected from rolling or vibratory compaction.

[0039] In some embodiments, after step 3), surface treatment can be further included.

[0040] Compared with the prior art, the present invention has the following technical effects:

[0041] Optimization of the aggregate angle of the asphalt pavement material: Compared with the conventional operation of optimizing the binder or the composition and structural complexity of the base material organic compounds in asphalt pavement materials, and at the same time, the material is prone to leakage and the waterproof performance cannot be effectively improved, in the present invention, it is proposed to improve the leak-proof performance of the asphalt pavement material by selecting and optimizing the aggregate angle, which can reduce the voids between the aggregates, thereby improving the waterproof performance of the asphalt pavement material. The construction is highly operable, simple and not complex.

[0042] At the same time, the stability and service life of the pavement are not damaged: The selection of the aggregate angle in the present invention does not affect the adhesion performance and crack resistance of the asphalt, thus affecting the stability and service life of the pavement material.

[0043] Drawings of the specification

[0044] The following are the attached drawings of the present invention to better illustrate the technical solutions and implementation manners of the present invention.

[0045] Appendix Figure 1 The frost resistance splitting coefficient of the anti-leakage asphalt pavement material sample.

[0046] Appendix Figure 2 For Example 1, different leakage coefficients are obtained when the angle is used as a variable and increased. Specific implementation manners

[0047] The present invention is described in more detail hereinafter to facilitate the understanding of the present invention.

[0048] Those skilled in the art will recognize that: the chemical reactions described in the present invention can be used to appropriately prepare many other compounds of the present invention, and other methods for preparing the compounds of the present invention are considered to be within the scope of the present invention. For example, the synthesis of those non-illustrative compounds according to the present invention can be successfully completed by those skilled in the art through modification methods, such as appropriately protecting interfering groups, by using other known reagents in addition to those described in the present invention, or making some conventional modifications to the reaction conditions. In addition, the reactions or known reaction conditions disclosed in the present invention are also generally recognized to be applicable to the preparation of other compounds of the present invention.

[0049] Example 1: Prepare an anti-leakage asphalt pavement material from asphalt aggregates. The specific operations are as follows: Mix the asphalt base material and the polymer SBS in a ratio of 90:10 at a temperature of 160 °C for 30 minutes to obtain an asphalt mixture; control the temperature at 170 °C and add 80 parts of sandstone aggregates to 10 parts of the molten asphalt mixture, stir it evenly with a stirrer, and then put it into a vibrating screen for screening. By controlling the vibration frequency and amplitude, make the sandstone aggregates form an angle of 20 degrees in the vibrating screen, and control the ratio at about 50%; add 5 parts of filler and mix to obtain the anti-leakage asphalt pavement material.

[0050] Example 2: Prepare an anti-leakage asphalt pavement material from asphalt aggregates. The specific operations are as follows: Mix the asphalt base material and the polymer SBS in a ratio of 90:10 at a temperature of 160 °C for 30 minutes to obtain an asphalt mixture; control the temperature at 170 °C and add 80 parts of sandstone aggregates to 10 parts of the molten asphalt mixture, stir it evenly with a stirrer, and then put it into a vibrating screen for screening. By controlling the vibration frequency and amplitude, make the sandstone aggregates form an angle of 30 degrees in the vibrating screen, and control the ratio at about 65%; add 5 parts of filler and mix to obtain the anti-leakage asphalt pavement material.

[0051] Example 3: Prepare a leak-proof asphalt pavement material from asphalt aggregates. The specific operation is as follows: Mix asphalt base material and polymer SBS in a ratio of 90:10 at a temperature of 160 °C for 30 minutes to obtain an asphalt mixture; control the temperature at 170 °C and add 80 parts of sandstone aggregates to 10 parts of the molten asphalt mixture, stir it evenly with a mixer, then put it into a vibrating screen for screening. By controlling the vibration frequency and amplitude, make the sandstone aggregates form an angle of 25 degrees in the vibrating screen, and control the proportion at about 50%; add 5 parts of filler and mix to obtain the leak-proof asphalt pavement material.

[0052] Example 4: Prepare a leak-proof asphalt pavement material from asphalt aggregates. The specific operation is as follows: Mix asphalt base material and polymer SBS in a ratio of 90:10 at a temperature of 160 °C for 30 minutes to obtain an asphalt mixture; control the temperature at 170 °C and add 80 parts of sandstone aggregates to 10 parts of the molten asphalt mixture, stir it evenly with a mixer, then put it into a vibrating screen for screening. By controlling the vibration frequency and amplitude, make the sandstone aggregates form an angle of 25 degrees in the vibrating screen, and control the proportion at about 60%; add 5 parts of filler and mix to obtain the leak-proof asphalt pavement material.

[0053] Test Example

[0054]

Leakage Coefficient Measurement Method

[0055] 1.1 Preparation Work

[0056] (1) Prepare a leak-proof cup with a diameter of 10 cm.

[0057] (2) Prepare a sample of the asphalt pavement material.

[0058] 1.2 Experimental Steps

[0059] (1) Put the sample into the leak-proof cup and add an appropriate amount of water.

[0060] (2) Press a metal disc with a diameter of 5 cm on the surface of the sample and apply a certain load on it.

[0061] (3) Record the height and time of the sample's descent.

[0062]

Experimental Calculation Formula and Data Processing

[0063] 2.1 Calculate the leakage coefficient

[0064] According to Darcy's law, the leakage coefficient in the asphalt pavement material can be calculated by the following formula:

[0065] K = Q / (A × H × ΔP / L)

[0066] Among them, K is the anti-leakage coefficient, with the unit of cm / s;

[0067] Q is the leakage flow rate, with the unit of cm 3 / s;

[0068] A is the cross-sectional area of the sample, with the unit of cm 2 ;

[0069] H is the thickness of the sample, with the unit of cm;

[0070] ΔP is the applied load, with the unit of Pa;

[0071] L is the length of the sample, with the unit of cm.

[0072] 2.2 Calculation of leakage flow rate

[0073] The leakage flow rate can be calculated by the following formula:

[0074] Q = (h2 - h1) × A / t

[0075] Among them, h2 is the final drop height of the sample, with the unit of cm;

[0076] h1 is the initial height of the sample, with the unit of cm;

[0077] A is the cross-sectional area of the sample, with the unit of cm 2 ;

[0078] t is the leakage time, with the unit of s.

[0079] 2.3 Calculation results of anti-leakage coefficient

[0080] According to the above formula, the unit of the calculated result of the leakage coefficient K is cm / s. The smaller the K value, the stronger the anti-leakage property of the sample.

[0081] For the experimental data of the anti-leakage asphalt pavement material samples (the sample size can be set as a square block with appropriate size) obtained in the above Examples 1-4, the inventor conducted a control test using the preparation method and process of Example 1, and prepared Comparative Sample 1 (too low sandstone aggregate angle, controlling the distribution ratio below 10 degrees to be greater than 90%) and Comparative Sample 2 (too high sandstone aggregate angle, controlling the distribution ratio greater than 40 degrees to be greater than 90%). The test results are shown in Table 1 below.

[0082] Table 1

[0083]

[0084] The results can show that with the optimization of the sandstone aggregate angle, the leakage coefficient gradually decreases. When the angle of the sandstone aggregate in the sample in the example is controlled between 20 - 30 degrees at an appropriate ratio, the leakage coefficient is lower than 10-7 cm / s. Compared with the samples of the present invention, the leak-proof performance of the comparative example is reduced. The optimization of the aggregate angle in the technical solution of the present invention has significantly improved the leak-proof performance of the asphalt material compared with other optimization methods in the prior art.

[0085] At the same time, it is shown by Figure 1 that while regulating the sandstone aggregate angle to improve the leak-proof performance of the asphalt material, its mechanical properties such as crack resistance are not lost. Figure 2 List the data points of different leakage coefficients obtained when the angle of Example 1 is used as a variable and other parameters remain unchanged and the angle increases. It can be seen that the leak-proof performance of the asphalt pavement material with the aggregate angle controlled between 20-30 degrees is also significantly improved compared with the samples outside the interval.

[0086] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention. The above describes the preferred embodiments of the present invention, but it is not intended to limit the present invention. Those skilled in the art can make improvements and changes to the embodiments disclosed herein without departing from the scope and spirit of the present invention.

Claims

1. A preparation method of a leak-proof asphalt pavement material, characterized in that: It includes the following steps: 1) Prepare the leak-proof asphalt binder: Using asphalt base material as the main raw material, adding polymers to the asphalt base material and mixing them to obtain the leak-proof asphalt binder. The asphalt base material and polymers are mixed at a temperature of 160 - 180 °C for 30 - 40 minutes; 2) Sandstone aggregate treatment: Select hard sandstone in Guangxi region. After crushing and screening, control the proportion of aggregate angles of 20 - 30 degrees to be 45 - 68%, the crushing value ≤ 15%, and the adhesion grade ≥ 4 levels; 3) Prepare the leak-proof asphalt pavement material: The leak-proof asphalt binder obtained in step 1) is mixed with sandstone aggregate and filler to obtain the leak-proof asphalt pavement material; among them, when mixing the sandstone aggregate, add it to the molten asphalt mixture, stir it evenly with a mixer, and then put it into a vibrating screen for screening. By controlling the vibration frequency and amplitude, a specific angle distribution is formed, and the proportion of the angle distribution of the sandstone aggregate between 20 - 30 degrees is 45 - 68%.

2. The preparation method of a leak-proof asphalt pavement material according to claim 1, characterized in that: The polymer contains modifiers, and the modifiers are selected from one or a combination of SBS, SBR, and EVA. Preferably, the weight ratio of the asphalt base material to the polymer is: 80 - 90:10 - 20.

3. The preparation method of a leak-proof asphalt pavement material according to claim 1, characterized in that: The aggregate is selected from one or a combination of sandstone and limestone, granite, basalt, and pebbles, and / or the filler is selected from one or a combination of slaked lime and cement. Preferably, the sandstone aggregate should meet: the saturated compressive strength ≥ 100 MPa, the water absorption rate ≤ 0.3%, and the disintegration resistance coefficient ≥ 90%.

4. The preparation method of a leak-proof asphalt pavement material as described in claim 1, characterized in that: In step 3), mix the above components and stir at a temperature of 150 - 170 °C for 20 - 30 minutes to obtain the leak-proof asphalt pavement material.

5. The preparation method of a leak-proof asphalt pavement material as described in claim 1, characterized in that: In step 3), it is characterized in that: the weight ratio of the leak-proof asphalt binder, aggregate, and filler is 5 - 10:80 - 90:5 - 10.

6. The preparation method of a leak-proof asphalt pavement material according to claim 1, characterized in that: In step 2), the vibrating screening technology is adopted, with a vibration frequency of 20 - 40 Hz, an amplitude of 2 - 5 mm, and a screening time of 10 - 15 minutes.

7. Construction process of a leak-proof asphalt pavement material, characterized in that: The construction process includes the following steps: 1) Pavement treatment: Before paving the leak-proof asphalt pavement material, treat the pavement, remove sundries, dust, and other impurities, and repair the damaged parts; 2) Primer spraying: Spray primer on the pavement to improve the adhesion between the pavement and the leak-proof asphalt pavement material; preferably, the primer contains tackifiers; 3) Lay the leak-proof asphalt pavement material: Construct according to the "graded gravel cushion - sandstone water-stable base - asphalt surface layer" structure, lay the leak-proof asphalt pavement material prepared by the preparation method described in any one of claims 1 to 6 on the pavement and compact it to form a leak-proof asphalt pavement.

8. The application process according to claim 4, characterized in that: The sandstone water-stable base uses skeleton dense type cement stabilized macadam, with a cement content of 4 - 5% and a 7-day unconfined compressive strength ≥ 5 MPa.

9. The application process according to claim 7, characterized in that: In step 3), the construction temperature is 120 - 140 °C, and the compaction temperature is 120 - 130 °C.

10. The application process according to claim 7, characterized in that: In step 3), the compaction method is selected from rolling or vibrating compaction.

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