A road base material and a method of making the same

Abstract

The application provides a road base material and a preparation method thereof, and comprises cement 1-5 parts, broken stone 50-70 parts, fly ash 4-8 parts, sand 5-15 parts, stone chips 5-15 parts, modified carboxymethyl cellulose 1-3 parts, modified polypropylene fiber 1-3 parts and water 4-10 parts. Through the technical scheme, the modified polypropylene fiber comprises graphene, the graphene not only further improves the hydrophilicity of the modified polypropylene fiber, but also effectively improves the tensile strength of the modified polypropylene fiber due to the special structure of the graphene honeycomb, the modified polypropylene fiber can be better dispersed in the cement, and thus the integrity of the road base material is improved, and the crack resistance of the road base material is improved.

Description

Technical Field

[0001] This invention relates to the field of road engineering materials, and more particularly to a road base material and its preparation method. Background Technology

[0002] In my country, semi-rigid pavement base materials are widely used for roadbed construction, among which cement-stabilized base materials are widely adopted due to their sufficient mechanical strength and good water resistance. However, due to the inherent characteristics of cement-stabilized materials and limitations of existing asphalt pavement construction techniques, the cracking and interlayer shear slip problems in cement-stabilized crushed stone asphalt pavements have not been effectively resolved. In particular, the early cracking of cement-stabilized crushed stone asphalt pavements, leading to early pavement defects, significantly shortens the service life of roads.

[0003] Cement-based grouting materials are the most commonly used non-chemical grouting slurries in underground engineering, but their anti-dispersion ability is extremely poor. In the traditional construction process of cement-stabilized crushed stone base asphalt pavement, the cement-stabilized base is first laid, the base is water-cured for 7 days, and then a tack coat is applied as a seal coat. This construction method has the following problems: when subjected to the scouring of water in high-pressure water-rich strata, the grouting material is easily washed away and diluted. In addition, cement-based grouting materials have high drying shrinkage in the later stage and are prone to cracking, which cannot achieve the purpose of long-term filling and reinforcement of the strata. The unstable moisture content of the base layer during water curing makes it sensitive to humidity changes, resulting in a state of alternating dryness and wetness that easily leads to shrinkage cracks and premature cracking. The base layer requires 7 days of curing, which is time-consuming, uneconomical, and susceptible to weather conditions, resulting in inconsistent quality. During curing, exposure to day and night temperature differences can cause temperature cracks, which may appear before the surface layer is laid. Furthermore, the top surface of the base layer is prone to contamination during curing, leading to uneven application of the oil-permeable layer and compromising the adhesion between the base and surface layers. This reduces the base and surface layers' resistance to cracking and shear slippage. The long construction period also results in significant disruption to traffic. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a road base material and its preparation method.

[0005] The present invention is achieved through the following technical solution: a road base material comprising the following raw materials in parts by weight: 1-5 parts cement, 50-70 parts crushed stone, 4-8 parts fly ash, 5-15 parts sand, 5-15 parts stone chips, 1-3 parts modified carboxymethyl cellulose, 1-3 parts modified polypropylene fiber, and 4-10 parts water.

[0006] As a preferred embodiment, the preparation method of modified polypropylene fibers specifically includes the following steps:

[0007] A1. Add 5-10 parts of graphene oxide to 1000 parts of ethanol solution, sonicate to dissolve for 30 min, add γ-(methacryloyloxy)propyltrimethoxysilane and sodium styrene sulfonate, heat to micro-reflux under stirring, react for 1 h, filter, remove the filtrate, wash the filtered solid 5 times with anhydrous ethanol to obtain a mixture.

[0008] A2. Add polypropylene to xylene and heat to 120°C to completely dissolve the polypropylene, thus obtaining a polypropylene solution.

[0009] A3. Slowly add the mixture to the polypropylene solution and stir at 130-150℃ for 0.5h. Then dry the mixture for 24-48h to obtain the modified polypropylene composite material. Melt spin the obtained graphene oxide modified polypropylene composite material to obtain modified polypropylene fiber.

[0010] As a preferred embodiment, the preparation method of modified carboxymethyl cellulose specifically includes the following steps:

[0011] B1. Dissolve carboxymethyl cellulose and acrylic acid in water, purge with nitrogen and stir for 50-70 minutes to obtain a mixture;

[0012] B2 adds potassium permanganate solution to the mixture prepared in B1, stirs evenly, heats to 60-80℃, and keeps warm for 3-5 hours to obtain modified methyl cellulose solution.

[0013] As a preferred embodiment, the weight ratio of acrylic acid, potassium permanganate, and carboxymethyl cellulose is 4:1:94.

[0014] As a preferred option, the cement is one or more of silicate cement, sulfoaluminate cement, and slag cement.

[0015] The particle size of the crushed stone is 2-7mm.

[0016] A method for preparing a road base material specifically includes the following steps:

[0017] S1. Weigh each raw material according to its weight percentage;

[0018] S2. Mix the crushed stone, fly ash, sand, and stone chips until they are evenly mixed.

[0019] S2, Secondary Mixing: Water, cement, carboxymethyl cellulose and modified polypropylene fiber are added to the preliminary mixture obtained in S2 and mixed and stirred evenly to obtain cement-stabilized crushed stone mixture.

[0020] The present invention, by adopting the above technical solution, has the following beneficial effects compared with the prior art: the modified polypropylene fiber includes graphene, which not only further improves the hydrophilicity of the modified polypropylene fiber, but also the special honeycomb structure of graphene can effectively improve the tensile strength of the modified polypropylene fiber. The modified polypropylene fiber can be better dispersed in cement, thereby improving the integrity of the road base material and thus improving the crack resistance of the road base material.

[0021] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Detailed Implementation

[0022] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0024] Preparation Example

[0025] The preparation method of modified polypropylene fibers specifically includes the following steps:

[0026] A1. Add 5-10 parts of graphene oxide to 1000 parts of ethanol solution, sonicate to dissolve for 30 min, add γ-(methacryloyloxy)propyltrimethoxysilane and sodium styrene sulfonate, heat to micro-reflux under stirring, react for 1 h, filter, remove the filtrate, wash the filtered solid 5 times with anhydrous ethanol to obtain a mixture.

[0027] A2. Add polypropylene to xylene and heat to 120°C to completely dissolve the polypropylene, thus obtaining a polypropylene solution.

[0028] A3. Slowly add the mixture to the polypropylene solution and stir at 130-150℃ for 0.5h. Then dry the mixture for 24-48h to obtain the modified polypropylene composite material. Melt spin the obtained graphene oxide modified polypropylene composite material to obtain modified polypropylene fiber.

[0029] Modified carboxymethyl cellulose specifically includes the following steps:

[0030] B1. Dissolve carboxymethyl cellulose and acrylic acid in water, purge with nitrogen and stir for 50-70 minutes to obtain a mixture;

[0031] B2 adds potassium permanganate solution to the mixture prepared in B1, stirs evenly, heats to 60-80℃, and keeps warm for 3-5 hours to obtain modified methyl cellulose solution.

[0032] Example 1

[0033] This embodiment provides a road base material, which includes the following raw materials in parts by weight: 4 parts cement, 55 parts crushed stone, 5 parts fly ash, 10 parts sand, 10 parts stone chips, 3 parts modified carboxymethyl cellulose, 3 parts modified polypropylene fiber, and 10 parts water.

[0034] This embodiment provides a method for preparing road base material, specifically including the following steps:

[0035] S1. Weigh each raw material according to its weight percentage;

[0036] S2. Mix the crushed stone, fly ash, sand, and stone chips until they are evenly mixed.

[0037] S2, Secondary Mixing: Water, cement, carboxymethyl cellulose and modified polypropylene fiber are added to the preliminary mixture obtained in S2 and mixed and stirred evenly to obtain cement-stabilized crushed stone mixture.

[0038] Example 2

[0039] This embodiment provides a road base material, which includes the following raw materials in parts by weight: 2 parts cement, 50 parts crushed stone, 4 parts fly ash, 5 parts sand, 15 parts stone chips, 3 parts modified carboxymethyl cellulose, 3 parts modified polypropylene fiber, and 10 parts water.

[0040] This embodiment provides a method for preparing road base material, specifically including the following steps:

[0041] S1. Weigh each raw material according to its weight percentage;

[0042] S2. Mix the crushed stone, fly ash, sand, and stone chips until they are evenly mixed.

[0043] S2, Secondary Mixing: Water, cement, carboxymethyl cellulose and modified polypropylene fiber are added to the preliminary mixture obtained in S2 and mixed and stirred evenly to obtain cement-stabilized crushed stone mixture.

[0044] Example 3

[0045] This embodiment provides a road base material, which includes the following raw materials in parts by weight: 3 parts cement, 65 parts crushed stone, 6 parts fly ash, 5 parts sand, 10 parts stone chips, 2 parts modified carboxymethyl cellulose, 2 parts modified polypropylene fiber, and 8 parts water.

[0046] This embodiment provides a method for preparing road base material, specifically including the following steps:

[0047] S1. Weigh each raw material according to its weight percentage;

[0048] S2. Mix the crushed stone, fly ash, sand, and stone chips until they are evenly mixed.

[0049] S2, Secondary Mixing: Water, cement, carboxymethyl cellulose and modified polypropylene fiber are added to the preliminary mixture obtained in S2 and mixed and stirred evenly to obtain cement-stabilized crushed stone mixture.

[0050] Example 4

[0051] This embodiment provides a road base material, which includes the following raw materials in parts by weight: 5 parts cement, 60 parts crushed stone, 8 parts fly ash, 15 parts sand, 12 parts stone chips, 1 part modified carboxymethyl cellulose, 1 part modified polypropylene fiber, and 5 parts water.

[0052] This embodiment provides a method for preparing road base material, specifically including the following steps:

[0053] S1. Weigh each raw material according to its weight percentage;

[0054] S2. Mix the crushed stone, fly ash, sand, and stone chips until they are evenly mixed.

[0055] S2, Secondary Mixing: Water, cement, carboxymethyl cellulose and modified polypropylene fiber are added to the preliminary mixture obtained in S2 and mixed and stirred evenly to obtain cement-stabilized crushed stone mixture.

[0056] Example 5

[0057] This embodiment provides a road base material, which includes the following raw materials in parts by weight: 2 parts cement, 70 parts crushed stone, 7 parts fly ash, 5 parts sand, 10 parts stone chips, 3 parts modified carboxymethyl cellulose, 3 parts modified polypropylene fiber, and 10 parts water.

[0058] This embodiment provides a method for preparing road base material, specifically including the following steps:

[0059] S1. Weigh each raw material according to its weight percentage;

[0060] S2. Mix the crushed stone, fly ash, sand, and stone chips until they are evenly mixed.

[0061] S2, Secondary Mixing: Water, cement, carboxymethyl cellulose and modified polypropylene fiber are added to the preliminary mixture obtained in S2 and mixed and stirred evenly to obtain cement-stabilized crushed stone mixture.

[0062] Example 6

[0063] This embodiment provides a road base material, which includes the following raw materials in parts by weight: 1 part cement, 70 parts crushed stone, 5 parts fly ash, 12 parts sand, 10 parts stone chips, 2 parts modified carboxymethyl cellulose, 2 parts modified polypropylene fiber, and 6 parts water.

[0064] This embodiment provides a method for preparing road base material, specifically including the following steps:

[0065] S1. Weigh each raw material according to its weight percentage;

[0066] S2. Mix the crushed stone, fly ash, sand, and stone chips until they are evenly mixed.

[0067] S2, Secondary Mixing: Water, cement, carboxymethyl cellulose and modified polypropylene fiber are added to the preliminary mixture obtained in S2 and mixed and stirred evenly to obtain cement-stabilized crushed stone mixture.

[0068] Compared with Example 1, Comparative Example 1 did not contain modified carboxymethyl cellulose;

[0069] Compared with Example 1, Comparative Example 2 did not contain modified polypropylene fibers;

[0070] Comparative Example 3, compared to Example 1, included unmodified carboxymethyl cellulose;

[0071] Compared with Example 1, Comparative Example 4 added unmodified polypropylene fibers.

[0072] According to the "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering" JTG E51-2009, the total drying shrinkage coefficient of the samples from Examples 1-7 and Comparative Examples 1-4 was tested.

[0073] The unconfined compressive strength of the prepared road base material was tested according to the testing standards of the national standard JTG 3430-2020 "Specifications for Geotechnical Testing of Highways". Testing environment: 25℃.

[0074] The test results are shown in Table 1:

[0075] Table 1

[0076]

[0077] Combining Examples 1-6 and Comparative Examples 1-4, the results show that the road base materials prepared in Examples 1-6 of this application have better performance in all aspects than the comparative examples, indicating that the road base materials prepared in this application perform better in terms of compressive strength and drying shrinkage coefficient. The modified polypropylene fibers include graphene, which not only further improves the hydrophilicity of the modified polypropylene fibers, but also the special honeycomb structure of graphene can effectively improve the tensile strength of the modified polypropylene fibers. The modified polypropylene fibers can be better dispersed in cement, thereby improving the integrity of the road base material and thus improving its crack resistance.

[0078] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0079] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A road base material, characterized in that, It comprises the following raw materials in parts by weight: 1-5 parts cement, 50-70 parts crushed stone, 4-8 parts fly ash, 5-15 parts sand, 5-15 parts stone chips, 1-3 parts modified carboxymethyl cellulose, 1-3 parts modified polypropylene fiber, and 4-10 parts water. The preparation method of the modified polypropylene fiber specifically includes the following steps: A1. Add 5-10 parts of graphene oxide to 1000 parts of ethanol solution, sonicate to dissolve for 30 min, add γ-(methacryloyloxy)propyltrimethoxysilane and sodium styrene sulfonate, heat to micro-reflux under stirring, react for 1 h, filter, remove filtrate, wash the filtered solid 5 times with anhydrous ethanol to obtain modified filter cake. A2. Add polypropylene to xylene and heat to 120°C to completely dissolve the polypropylene, thus obtaining a polypropylene solution. A3. Slowly add the modified filter cake to the polypropylene solution and stir at 130-150℃ for 0.5h. Then dry the mixture for 24-48h to obtain the graphene oxide modified polypropylene composite material. Melt spin the obtained graphene oxide modified polypropylene composite material to obtain modified polypropylene fiber. The preparation method of the modified carboxymethyl cellulose specifically includes the following steps: B1. Dissolve carboxymethyl cellulose and acrylic acid in water, purge with nitrogen and stir for 50-70 minutes to obtain a mixture; B2. Add potassium permanganate solution to the mixture prepared in B1, stir evenly and heat to 60-80℃, keep warm for 3-5 hours to obtain modified carboxymethyl cellulose solution.

2. The road base material according to claim 1, characterized in that, The weight ratio of acrylic acid, potassium permanganate, and carboxymethyl cellulose is 4:1:

94.

3. The road base material according to claim 1, characterized in that, The cement is one or more of silicate cement, sulfoaluminate cement, and slag cement.

4. A road base material according to claim 1, characterized in that, The particle size of the crushed stone is 2-7mm.

5. A method for preparing a road base material as described in claim 1, characterized in that, Specifically, the following steps are included: S1. Weigh each raw material according to its weight percentage; S2. Mix and stir the crushed stone, fly ash, sand, and stone chips until they are evenly mixed to obtain a preliminary mixture; S3. Secondary mixing: Water, cement, modified carboxymethyl cellulose, and modified polypropylene fiber are added to the preliminary mixture obtained in S2 and mixed and stirred evenly to obtain the road base material.

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