Anti-freezing pavement base based on coal gangue burning slag

Abstract

The utility model discloses an anti-freezing pavement base based on coal gangue combustion slag, which comprises a coal gangue combustion slag graded broken stone hardcore, 4.5% cement stabilized coal gangue combustion slag graded broken stone, 5% cement stabilized coal gangue combustion slag graded broken stone, asphalt broken stone, first medium-grain asphalt concrete and second medium-grain asphalt concrete, the medium-grain asphalt concrete is laid on the medium-grain asphalt concrete, the first medium-grain asphalt concrete is laid on the asphalt macadam, and the asphalt macadam is laid on the 5% cement stabilized coal gangue combustion slag graded macadam. The 5% cement stabilized coal gangue combustion slag graded broken stone is laid above the 4.5% cement stabilized coal gangue combustion slag graded broken stone. The coal gangue burning slag is small in density and heat conductivity coefficient, the road freezing depth is reduced after the coal gangue burning slag is used for a base layer, great benefits are brought to the overall anti-freezing performance of a road subgrade pavement in a heavy freezing area, the service life of a pavement structure layer and a subgrade can be effectively prolonged, and the maintenance cost is saved.

Description

Technical Field

[0001] This utility model relates to the field of coal gangue slag roadbed technology, and in particular to a frost-resistant road base course based on coal gangue slag. Background Technology

[0002] Coal gangue slag = self-igniting coal gangue = coal gangue that has self-ignited = commonly known as "fire-burned gangue".

[0003] Coal gangue is a general term encompassing non-spontaneously combusted coal gangue, coal gangue that is spontaneously combusting, and coal gangue that has completely combusted (coal gangue slag). The main differences between non-spontaneously combusted coal gangue and coal gangue that has completely combusted (coal gangue slag) are: ① The rock and engineering properties are completely different; ② The quantity of coal gangue slag is much smaller than that of unburned coal gangue, limiting the selection options; ③ Even when used in cement-stabilized crushed stone or cement concrete, non-spontaneously combusted coal gangue does not achieve good performance, uniformity, and stability. However, the coal gangue slag-graded crushed stone and manufactured sand used in our study achieve excellent performance, uniformity, and stability. Because coal gangue slag contains no combustible impurities, the strength of sandstone in the original rock increases after combustion. The strength of mudstone, argillaceous sandstone, or argillaceous shale in the original rock also increases after combustion, and the strength uniformity (stability) is relatively good.

[0004] With the implementation of environmental protection policies, the requirements for the mining and processing of sand and gravel will become increasingly stringent, and sand and gravel will gradually become scarce resources. Coal gangue, as a solid industrial waste, has large emissions, occupies a lot of land, and seriously pollutes the environment, severely impacting people's lives, production, and physical and mental health. Major coal-producing areas in Heilongjiang Province have large quantities of coal gangue and its slag, occupying significant amounts of land resources.

[0005] With the large-scale construction of highways and infrastructure, the total thickness of pavement structural layers often needs to reach over 90cm to meet the frost resistance requirements of the specifications, resulting in high material consumption and a large amount of construction work. The utilization of coal gangue ash in engineering has broad prospects. The large-scale consumption and application of accumulated coal gangue ash can solve problems related to engineering materials, environmental protection, and land resources, achieving multiple benefits. Currently, coal gangue is rarely used as a paving material for highways. Using coal gangue as a raw material for highways could reduce environmental and land resource issues. Utility Model Content

[0006] The purpose of this utility model is to solve the above-mentioned technical problems by proposing a frost-resistant road base course based on coal gangue slag.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The frost-resistant road base course based on coal gangue slag includes a coal gangue slag graded crushed stone subbase, 4.5% cement-stabilized coal gangue slag graded crushed stone, 5% cement-stabilized coal gangue slag graded crushed stone, asphalt macadam, a first medium-grained asphalt concrete, and a second medium-grained asphalt concrete laid on top of the first medium-grained asphalt concrete. The first medium-grained asphalt concrete is laid on top of the asphalt macadam, the asphalt macadam is laid on top of the 5% cement-stabilized coal gangue slag graded crushed stone, the 5% cement-stabilized coal gangue slag graded crushed stone is laid on top of the 4.5% cement-stabilized coal gangue slag graded crushed stone, and the 4.5% cement-stabilized coal gangue slag graded crushed stone is laid on top of the coal gangue slag graded crushed stone subbase.

[0009] Preferably, the thickness of the coal gangue slag graded crushed stone cushion layer is 20cm.

[0010] Preferably, the thickness of the 4.5% cement-stabilized coal gangue slag graded crushed stone is 20cm.

[0011] Preferably, the thickness of the 5% cement-stabilized coal gangue slag graded crushed stone is 20-23 cm.

[0012] Preferably, the thickness of the asphalt macadam is 8 cm.

[0013] Preferably, the thickness of the first medium-grained asphalt concrete is 6 cm.

[0014] Preferably, the thickness of the second medium-grained asphalt concrete is 5 cm.

[0015] Compared with the prior art, the advantages of this utility model are as follows:

[0016] In summary, the coal gangue slag in this invention has a low density and low thermal conductivity, which reduces the freezing depth of roads after being used as a base layer. This is of great benefit to the overall frost resistance of roadbeds and pavements in heavily frozen areas, can effectively extend the service life of pavement structural layers and roadbeds, and save maintenance costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the anti-freezing road base course based on coal gangue slag proposed in this utility model;

[0018] Figure 2 A graph showing the relationship between age and cumulative water loss rate;

[0019] Figure 3 A graph showing the relationship between age and cumulative shrinkage strain;

[0020] Figure 4 This is a temperature-range thermal shrinkage coefficient diagram;

[0021] Figure 5This is a graph showing the average temperature shrinkage coefficient.

[0022] In the figure: 1 Coal gangue slag graded crushed stone cushion layer, 2 4.5% cement stabilized coal gangue slag graded crushed stone, 3 5% cement stabilized coal gangue slag graded crushed stone, 4 Asphalt crushed stone, 5 First medium-grained asphalt concrete, 6 Second medium-grained asphalt concrete. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0024] Reference Figures 1-5 The frost-resistant road base course based on coal gangue slag includes a coal gangue slag graded crushed stone subbase 1, a 4.5% cement-stabilized coal gangue slag graded crushed stone 2, a 5% cement-stabilized coal gangue slag graded crushed stone 3, asphalt macadam 4, a first medium-grained asphalt concrete 5, and a second medium-grained asphalt concrete 6. The second medium-grained asphalt concrete 6 has a thickness of 5 cm and is laid on top of the first medium-grained asphalt concrete 5. The first medium-grained asphalt concrete 5 is laid on top of the asphalt macadam 4 and has a thickness of 6 cm.

[0025] The asphalt-stabilized crushed stone 4 is laid on top of the 5% cement-stabilized coal gangue slag graded crushed stone 3, and the thickness of the asphalt-stabilized crushed stone 4 is 8cm. The 5% cement-stabilized coal gangue slag graded crushed stone 3 is laid on top of the 4.5% cement-stabilized coal gangue slag graded crushed stone 2, and the thickness of the 5% cement-stabilized coal gangue slag graded crushed stone 3 is 20-23cm.

[0026] The 4.5% cement-stabilized coal gangue slag graded crushed stone 2 is laid on top of the coal gangue slag graded crushed stone cushion layer 1. The thickness of the 5% cement-stabilized coal gangue slag graded crushed stone 2 is 20cm, and the thickness of the coal gangue slag graded crushed stone cushion layer 1 is 20cm.

[0027] When the roadbed of a high-grade highway is in a moderately moist state, in order to meet the frost resistance requirements of the "Specification", the total thickness of the pavement structure layer often needs to reach more than 90cm (from top to bottom: AC-16 first medium-grained asphalt concrete 5cm, AC-20 second medium-grained asphalt concrete 6cm, asphalt macadam 8cm, 4.5% cement stabilized conventional graded crushed stone 32cm, 4.0% cement stabilized conventional graded crushed stone 20cm, conventional graded crushed stone subbase 20cm). However, by using coal gangue slag to make aggregate for the subbase, base course and top course, the total thickness of the pavement structure layer can be effectively reduced to about 80cm.

[0028] A more detailed explanation of this utility model follows:

[0029] 1. Using large-scale mining equipment, coal gangue slag is processed into 4-5 grades of mechanized aggregate (crushed stone and manufactured sand), with the first batch exceeding 100 cubic meters and the second batch exceeding 1000 cubic meters (unseen in China).

[0030] 2. A 5% cement-stabilized coal gangue slag machine-made aggregate was developed to completely replace conventional crushed stone and sand or manufactured sand. A complete set of tests was conducted, and a 50m long secondary highway upper base test road was successfully paved (unseen in China).

[0031] 3. Regarding freeze resistance—After spontaneous combustion, coal gangue forms coal gangue slag. During the combustion process, excessive moisture, including free and bound water, is released from the particles under high temperatures. Excessive high temperatures and calcination result in a rough surface and numerous pores or pore channels within the coal gangue slag particles. Furthermore, coal gangue slag, primarily composed of fine sandstone and mudstone, has a relatively low density. These factors—low density, low thermal conductivity of the rock minerals (sand and clay), rough surface, and numerous internal pores—lead to a significantly lower thermal conductivity for coal gangue slag particles compared to conventional basalt and granite. Moreover, the thermal conductivity or thermophysical property coefficient of cement-stabilized coal gangue slag crushed stone is approximately 10% lower than that of conventional cement-stabilized crushed stone.

[0032] Therefore, coal gangue slag material has a very good heat preservation effect and can effectively reduce the frost depth of roads. Among them, the bottom layer without cement has a very obvious advantage in heat preservation, while the upper and lower layers with cement will also have an advantage of about 10%.

[0033] Thinning the structural layer can reduce the thickness of the base layer construction, reduce materials, and save material costs of approximately 20 yuan per square meter of road surface, while also saving some construction time.

[0034] The thermal conductivity of red brick is approximately 0.57 W / (m·℃), while that of ordinary concrete is 1.28 W / (m·℃). The maximum compacted dry density of cement-stabilized coal gangue slag crushed stone is about 10% lower than that of cement-stabilized conventional crushed stone.

[0035] in;

[0036] The properties of coal gangue slag raw materials are shown in Table 1 below. The density test results of coal gangue slag are also included.

[0037]

[0038] The crushing value test results are shown in Table 2 below:

[0039]

[0040] The results of water absorption rate determination for coal gangue of different particle sizes are shown in Table 3 below:

[0041]

[0042] Splitting strength: Compared with conventional cement-stabilized crushed stone, the 7-day splitting strength of cement-stabilized slag crushed stone mixture is basically the same, but the 28-day splitting strength is 0.21 MPa higher, or 31.4%, and has reached the 90-day splitting strength of conventional cement-stabilized crushed stone; the average 200-day strength of 1.02 MPa is significantly greater than the 0.87 MPa of conventional cement crushed stone at 90 days; as shown in Table 4 below:

[0043]

[0044] The shrinkage test results are shown in Table 5 below:

[0045]

[0046] Based on the drying shrinkage test data of the above-mentioned cement-stabilized slag-crushed stone mixture and with reference to conventional cement-stabilized crushed stone mixture, the following test comparison chart is drawn, as follows: Figure 2 , Figure 3 As shown;

[0047] Thermostatic shrinkage test, as shown in Table 6 below:

[0048]

[0049] Results and data analysis:

[0050] Based on the above experimental data analysis, temperature-range temperature shrinkage coefficient diagrams and average temperature shrinkage coefficient diagrams for each range are plotted as follows: Figure 4 and 5 As shown in the figure, cement slag crushed stone and conventional cement crushed stone are compared and contrasted.

[0051] freeze-thaw test

[0052] The freeze-thaw test results of cement-stabilized slag crushed stone at 7 days and 28 days are shown in Tables 6 and 7:

[0053] 7-day freeze-thaw test results

[0054]

[0055] 28-day freeze-thaw test results

[0056]

[0057] Compressive Resilient Modulus (Top Surface Method) Test

[0058] The compressive resilient modulus (top surface method) test results of cement-stabilized slag-aggregate mixture are shown in Table 8 below:

[0059]

[0060] In summary, coal gangue slag has a low density and low thermal conductivity, which reduces the freezing depth of roads when used as a base layer. This is of great benefit to the overall frost resistance of roadbeds and pavements in heavily frozen areas, can effectively extend the service life of pavement structural layers and roadbeds, and save maintenance costs.

[0061] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A frost-resistant road base course based on coal gangue slag, characterized in that, The structure includes a coal gangue slag graded crushed stone cushion layer (1), 4.5% cement-stabilized coal gangue slag graded crushed stone (2), 5% cement-stabilized coal gangue slag graded crushed stone (3), asphalt crushed stone (4), a first medium-grained asphalt concrete (5), and a second medium-grained asphalt concrete (6). The second medium-grained asphalt concrete (6) is laid on top of the first medium-grained asphalt concrete (5), the first medium-grained asphalt concrete (5) is laid on top of the asphalt crushed stone (4), the asphalt crushed stone (4) is laid on top of the 5% cement-stabilized coal gangue slag graded crushed stone (3), the 5% cement-stabilized coal gangue slag graded crushed stone (3) is laid on top of the 4.5% cement-stabilized coal gangue slag graded crushed stone (2), and the 4.5% cement-stabilized coal gangue slag graded crushed stone (2) is laid on top of the coal gangue slag graded crushed stone cushion layer (1).

2. The frost-resistant road base course based on coal gangue slag according to claim 1, characterized in that, The thickness of the coal gangue slag graded crushed stone cushion layer (1) is 20cm.

3. The frost-resistant road base course based on coal gangue slag according to claim 1, characterized in that, The thickness of the 5% cement-stabilized coal gangue slag graded crushed stone (2) is 20cm.

4. The frost-resistant road base course based on coal gangue slag according to claim 1, characterized in that, The thickness of the 5% cement-stabilized coal gangue slag graded crushed stone (3) is 20-23cm.

5. The frost-resistant road base course based on coal gangue slag according to claim 1, characterized in that, The thickness of the asphalt macadam (4) is 8 cm.

6. The frost-resistant road base course based on coal gangue slag according to claim 1, characterized in that, The thickness of the first medium-grained asphalt concrete (5) is 6 cm.

7. The frost-resistant road base course based on coal gangue slag according to claim 1, characterized in that, The thickness of the second medium-grained asphalt concrete (6) is 5 cm.

Images