Light aggregate asphalt concrete based on slag ceramsite of waste incineration power plant

Abstract

This invention relates to a lightweight aggregate asphalt concrete based on ceramsite from waste-to-energy incineration plant slag, belonging to the technical field of road engineering materials. This invention provides an asphalt concrete using ceramsite from power plant slag as lightweight aggregate. By optimizing the ceramsite sintering process and asphalt mix proportions, it achieves the dual goals of solid waste resource utilization and improved pavement material performance. The asphalt concrete comprises ceramsite from slag, modified asphalt, crushed stone, sand, mineral powder, and a coupling agent. This invention effectively utilizes waste slag, resulting in lightweight and high-strength concrete that can reduce structural weight by more than 20%, has low thermal conductivity, and is suitable for urban roads and lightweight bridge pavement projects, demonstrating significant environmental, economic, and social benefits.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of road engineering materials, and particularly relates to an environmentally-friendly asphalt concrete with high-strength slag ceramsite as light aggregate, which is prepared by taking slag from a waste incineration power plant as a main raw material, and a preparation method thereof. The environmentally-friendly asphalt concrete is suitable for urban roads, bridge deck pavement and other projects with light weight requirements. BACKGROUND

[0002] Traditional asphalt concrete relies heavily on natural aggregates such as gravel and sandstone. Large-scale exploitation of these non-renewable resources not only consumes huge environmental resources, causing mountain destruction and soil erosion, but also causes irreversible damage to the ecological system. With the continuous advancement of global infrastructure construction, high-quality natural aggregates are increasingly scarce, and their prices are rising. Therefore, finding environmentally-friendly materials to replace natural aggregates has become a key problem to be solved in the field of road engineering.

[0003] At the same time, with the acceleration of urbanization and the popularization of waste incineration technology, the amount of slag produced by waste incineration power plants is increasing, and the stockpiled amount is huge. At present, the main treatment method of such slag is still traditional landfill, which not only occupies a large amount of valuable land resources, but also contains heavy metals and soluble salt components that pose a long-term environmental risk of polluting the soil and groundwater. Under the policy guidance of "waste-free city" and "circular economy", realizing high-value resource utilization of slag, and even the "zero landfill" goal, has become an inevitable trend of industry development.

[0004] To solve the above problems, some research has attempted to use ceramsite as light aggregate. However, existing ceramsite is mostly made of natural mineral raw materials such as clay and shale, and is essentially still dependent on the consumption of natural resources, and has a high production cost. More importantly, such traditional ceramsite often has low strength and poor adhesion to asphalt, and is easily broken during high-temperature mixing, which cannot meet the stringent requirements of asphalt mixture on aggregate strength. On the other hand, if untreated slag is directly used as aggregate, due to its inherent defects of porosity, high water absorption and low strength, it will absorb a large amount of asphalt, resulting in insufficient strength, poor water stability and poor durability of asphalt concrete, which cannot meet the road performance standards.

[0005] Therefore, it is of great practical significance and application value to develop a new type of light aggregate that can not only consume solid waste, but also meet the requirements of high-performance pavement. SUMMARY

[0006] The purpose of the present application is to provide light aggregate asphalt concrete based on slag ceramsite from a waste incineration power plant and a preparation method thereof, which converts waste incineration slag into high-performance ceramsite aggregate, and then optimizes the raw material parameters to prepare asphalt concrete with key road performance such as light weight, high strength, deformation resistance and permeability resistance.

[0007] The object of the present application can be achieved by the following technical solutions:

[0008] A light aggregate asphalt concrete based on slag ceramsite of a waste incineration power plant, comprising the following raw materials:

[0009] Slag ceramsite, modified asphalt, sand, mineral powder and coupling agent;

[0010] The slag ceramsite is a ceramsite made of treated finely ground slag (slag of a waste incineration power plant) as raw material, with bonding material and foaming material, through batching, mixing, granulation and firing at a high temperature of 1050-1150℃, with a density of 600-1100kg / m 3 , a cylinder compressive strength of 5-12MPa, a water absorption rate of ≤5%, and a particle size of ≤12mm.

[0011] The slag ceramsite comprises foamed ceramsite (density of 600-900kg / m 3 , cylinder compressive strength of 5-10MPa, water absorption rate of ≤5%, and particle size of 3-12mm (3-5mm is called ceramsite sand)) and sintered ceramsite (density of 900-1100kg / m 3 , cylinder compressive strength of 8-12MPa, water absorption rate of ≤4%, and particle size of 3-16mm).

[0012] As a preferred technical solution of the present application, the modified asphalt is SBS modified asphalt; and the preparation method of the SBS modified asphalt comprises the following steps:

[0013] A1, heat the asphalt to 170-180℃, add SBS particles and aromatic oil compatibilizer and mix uniformly;

[0014] A2, add 0.1-0.3% sulfur of the mass of the asphalt to the mixture prepared in step A1 and mix uniformly, keep the temperature at 170-180℃, and stir at a speed of 50-100rpm for 2-4h.

[0015] As a preferred technical solution of the present application, the mass ratio of the asphalt, SBS particles and aromatic oil compatibilizer in step A1 is 100:4.5-5.5:1.8-2.5.

[0016] As a preferred technical solution of the present application, the particle size of the sand is 0.3-4.75mm.

[0017] As a preferred technical solution of the present application, the mineral powder is limestone powder with a particle size of less than 0.075mm.

[0018] As a preferred technical solution of the present application, the coupling agent is silane coupling agent KH-550.

[0019] As a preferred technical scheme of the present application, the mass ratio of the slag ceramsite, modified asphalt, gravel, sand, and mineral powder is 25-30:4.5-5.5:0-10:15-20:8-10.

[0020] Further, the preparation method of the light aggregate asphalt concrete based on the slag ceramsite of the waste incineration power plant comprises the following steps:

[0021] (1) mixing the slag ceramsite with a coupling agent KH-550;

[0022] (2) heating the modified asphalt to 160-170 DEG C, and sequentially adding the slag ceramsite treated with the coupling agent prepared in step (1), gravel, sand, and mineral powder and mixing them uniformly;

[0023] (3) performing Marshall compaction on the mixture in step (2) at 145-155 DEG C, and controlling the void ratio to be 4-6%.

[0024] Further, the light aggregate asphalt concrete based on the slag ceramsite of the waste incineration power plant has a thermal conductivity of ≤0.4 W / m·K.

[0025] The present application has the following advantages:

[0026] (1) The present application uses the slag of the waste incineration power plant as the core raw material to prepare the ceramsite, and ceramic polishing slag is used as the batching material (binder and foaming agent) for preparing the ceramsite. The ceramic polishing slag is the solid waste of the ceramic industry, and the 0.40-100 micron ultrafine powder has good bonding forming (particle) property. The main chemical components are: Al2O3 16-18%, SiO2 68-69%, Fe2O3 0.7-1.2%, CaO 0.6-0.8%, MgO 3-4%, Na2O 1-2%, K2O 1-1.3%, SiC 1.5-4%. The ceramic polishing slag contains ceramic and grinding head components (silicon carbide SiC). The internal foaming principle of silicon carbide in the semi-molten state of the material forms internal closed micropores, and the slag ceramsite has high strength, low density, and low water absorption rate, and the utilization rate of the slag is ≥50%. The amount of landfill of the by-products of waste incineration is greatly reduced, and the pollution risk of solid waste to the soil and underground water is reduced. At the same time, the slag ceramsite replaces the traditional natural aggregate, reduces the mining amount of natural minerals, reduces the damage to the ecological environment, and promotes the green and sustainable development of the road material field.

[0027] (2) On the one hand, the present invention uses slag ceramsite with a density of only 600-1100 kg / m3, which can reduce the weight of asphalt concrete by more than 20%, making it particularly suitable for projects with requirements for lightweight paving such as soft soil foundations, elevated pavements, and old road reconstruction. It can reduce the bearing pressure of the roadbed and reduce the risk of structural settlement. On the other hand, the higher compressive strength of ceramsite is higher than that of traditional lightweight aggregate asphalt concrete, ensuring the road surface's resistance to rutting and damage. In addition, the closed-cell structure in ceramsite makes the concrete have a low thermal conductivity, which can effectively reduce the absorption and transfer of heat on the road surface, help alleviate the urban heat island effect, and improve the comfort of urban living.

[0028] (3) From the perspective of raw material cost, the cost of obtaining slag, as a by-product of waste incineration plant, is much lower than that of shale ceramsite, which reduces the production cost of the present invention compared with shale ceramsite asphalt concrete. From the perspective of engineering application, the reduction in concrete weight not only reduces energy consumption and manpower input in transportation and construction stages, but also reduces the material usage and construction difficulty of roadbed and base course, further compressing the overall engineering cost and making it economically feasible for widespread promotion. Detailed Implementation

[0029] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0030] Example 1

[0031] A lightweight aggregate asphalt concrete based on ceramsite from waste-to-energy incineration plant slag comprises the following raw materials:

[0032] Slag ceramsite, modified asphalt, crushed stone, sand, mineral powder, and coupling agent;

[0033] The slag ceramsite is slag from a waste-to-energy plant, with a density of 700 kg / m³, a compressive strength of 8 MPa, and a water absorption rate of 5%.

[0034] The modified asphalt is SBS modified asphalt; the method for preparing the SBS modified asphalt includes the following steps:

[0035] A1. Heat the asphalt to 175℃, add SBS particles and aromatic oil compatibilizer and mix evenly.

[0036] A2. Add 0.2% sulfur by weight of asphalt to the mixture obtained in step A1 and mix well. Maintain the temperature at 175℃ and stir at 70 rpm for 3 hours.

[0037] The mass ratio of asphalt, SBS particles, and aromatic oil compatibilizer in step A1 is 100:5:2.

[0038] The sand particle size is 0.3-4.75mm.

[0039] The mineral powder is 200-mesh limestone powder with a particle size of less than 0.075 mm.

[0040] The coupling agent is silane coupling agent KH-550.

[0041] The mass ratio of the slag ceramsite, modified asphalt, crushed stone, sand, and mineral powder is 28:5:5:18:9.

[0042] The method for preparing lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag includes the following steps:

[0043] (1) Mix the slag ceramsite with coupling agent KH-550;

[0044] (2) Heat the modified asphalt to 165°C and add the slag ceramsite, crushed stone, sand and mineral powder treated with coupling agent obtained in step (1) in sequence and mix them evenly.

[0045] (3) The mixture from step (2) was subjected to Marshall compaction at 150°C, and the void ratio was controlled to be 5%.

[0046] Example 2

[0047] A lightweight aggregate asphalt concrete based on ceramsite from waste-to-energy incineration plant slag comprises the following raw materials:

[0048] Slag ceramsite, modified asphalt, crushed stone, sand, mineral powder, and coupling agent;

[0049] The slag ceramsite mentioned above is slag ceramsite from a power plant, with a density of 900 kg / m³. 3 The compressive strength of the cylinder is 10MPa, the water absorption rate is 4%, and the particle size is 5-15mm.

[0050] The modified asphalt is SBS modified asphalt.

[0051] The sand has a particle size of 0.15-4.75 mm.

[0052] The mineral powder is 200-mesh limestone powder.

[0053] The mass ratio of the slag ceramsite, modified asphalt, crushed stone, sand and mineral powder is 28:5:10:18:9.

[0054] The plant-mixed hot method for preparing lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag includes the following steps:

[0055] (1) Mix the slag ceramsite with coupling agent KH-550;

[0056] (2) Heat the modified asphalt to 165°C and add mineral powder, sand and the uniform slag ceramsite mixture prepared in step (1) in sequence.

[0057] (3) The mixture from step (2) was subjected to Marshall compaction at 150°C to control the void ratio to 4%.

[0058] Example 3

[0059] A lightweight aggregate asphalt concrete based on ceramsite from waste-to-energy incineration plant slag comprises the following raw materials:

[0060] Slag ceramsite, modified asphalt, sand, mineral powder, and coupling agent;

[0061] The slag ceramsite is slag from a waste-to-energy plant, with a density of 1100 kg / m³, a compressive strength of 10 MPa, and a water absorption rate of 5%.

[0062] The modified asphalt is SBS modified asphalt; the method for preparing the SBS modified asphalt includes the following steps:

[0063] A1. Heat the asphalt to 180℃, add SBS particles and aromatic oil compatibilizer and mix evenly;

[0064] A2. Add 0.3% sulfur by weight of asphalt to the mixture obtained in step A1 and mix well. Maintain the temperature at 180℃ and stir at 100 rpm for 4 hours.

[0065] The mass ratio of asphalt, SBS particles, and aromatic oil compatibilizer in step A1 is 100:5.5:2.5.

[0066] The sand particle size is 0.3-4.75mm.

[0067] The mineral powder is 200-mesh limestone powder.

[0068] The coupling agent is silane coupling agent KH-550.

[0069] The mass ratio of the slag ceramsite, modified asphalt, crushed stone, sand, and mineral powder is 30:5.5:10:20:10.

[0070] The method for preparing lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag includes the following steps:

[0071] (1) Mix the slag ceramsite with coupling agent KH-550;

[0072] (2) Heat the modified asphalt to 170°C and add the slag ceramsite, crushed stone, sand and mineral powder treated with coupling agent obtained in step (1) in sequence and mix evenly.

[0073] (3) The mixture from step (2) was subjected to Marshall compaction at 155°C, and the void ratio was controlled to be 6%.

[0074] Example 4

[0075] A lightweight aggregate asphalt concrete based on ceramsite from waste-to-energy incineration plant slag comprises the following raw materials:

[0076] Slag ceramsite, modified asphalt, sand, mineral powder, and coupling agent;

[0077] The slag ceramsite is slag from a waste-to-energy plant, with a density of 600 kg / m³, a compressive strength of 8 MPa, and a water absorption rate of 5%.

[0078] The modified asphalt is SBS modified asphalt; the method for preparing the SBS modified asphalt includes the following steps:

[0079] A1. Heat the asphalt to 170℃, add SBS particles and aromatic oil compatibilizer and mix evenly;

[0080] A2. Add 0.1% sulfur by weight of asphalt to the mixture obtained in step A1 and mix well. Maintain the temperature at 170℃ and stir at 50 rpm for 2 hours.

[0081] The mass ratio of asphalt, SBS particles and aromatic oil compatibilizer in step A1 is 100:4.5:1.8.

[0082] The sand particle size is 0.3-4.75mm.

[0083] The mineral powder is 200-mesh limestone powder.

[0084] The coupling agent is silane coupling agent KH-550.

[0085] The mass ratio of the slag ceramsite, modified asphalt, crushed stone, sand, and mineral powder is 25:4.5:5:15:8.

[0086] The method for preparing lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag includes the following steps:

[0087] (1) Mix the slag ceramsite with coupling agent KH-550;

[0088] (2) Heat the modified asphalt to 160°C and add the slag ceramsite, crushed stone, sand and mineral powder treated with coupling agent obtained in step (1) in sequence and mix evenly.

[0089] (3) The mixture from step (2) was subjected to Marshall compaction at 145°C, and the void ratio was controlled to be 5%.

[0090] Comparative Example 1

[0091] Based on Example 1, the slag ceramsite selected is ceramsite with a density D of 1100 and a cylinder compressive strength of 12MPa, while the rest remains the same as in Example 1.

[0092] Comparative Example 2

[0093] Based on Example 1, the slag ceramsite selected is ceramsite with a density of D500 and a cylinder compressive strength of 6MPa, while the rest remains the same as in Example 1.

[0094] Comparative Example 3

[0095] Based on Example 1, slag ceramsite with a water absorption rate of 8% was selected, while the rest remained the same as in Example 1.

[0096] Comparative Example 4

[0097] Based on Example 1, shale ceramsite was used instead of slag ceramsite, while the rest remained the same as in Example 1.

[0098] Comparative Example 5

[0099] Based on Example 1, SBS modified asphalt was replaced with unmodified asphalt, while the rest remained the same as in Example 1.

[0100] Comparative Example 6

[0101] Based on Example 1, step (1) of mixing slag ceramsite with coupling agent is omitted, and the rest remains the same as in Example 1.

[0102] Performance testing:

[0103] According to the JTG E20-2011 standard, the dynamic stability was tested using a 5cm thick test section of the sample paving in the examples and comparative examples.

[0104] The freeze-thaw splitting strength ratio of the test examples and comparative samples were tested according to the JTG E20 T0729 standard.

[0105] The thermal conductivity of the test examples and comparative samples was determined according to ISO 22007-2 standard.

[0106] The density of dry weight samples was tested according to the JTG E20 T0705 standard test examples and comparative examples.

[0107]

[0108]

[0109] The test results show that the example, using high-strength slag ceramsite and modified asphalt, forms a high-strength aggregate skeleton and elastic asphalt mastic system, exhibiting excellent stability. The silane coupling agent treatment enhances the interfacial bonding between the asphalt and ceramsite, forming a waterproof barrier. The freeze-thaw splitting strength ratio is above 88%, and the density is 2.00-2.25 g / cm³. 3 The goal of lightweighting was achieved by using the porous structure of slag ceramsite, which makes it an insulating material and significantly reduces the thermal conductivity of concrete.

[0110] Comparative Example 1 uses high-density ceramsite, which has high strength and forms a solid skeleton, but it sacrifices lightweight and increases thermal conductivity. Comparative Example 2 demonstrates that the superiority of this invention lies in finding the optimal balance between performance and lightweight, that is, achieving lightweight while meeting road performance requirements, rather than simply pursuing low density. Comparative Example 3 uses ceramsite with high water absorption, which affects long-term water stability and thus durability. Comparative Example 4 uses shale ceramsite instead of slag ceramsite, which has lower strength, possibly due to the smooth surface of shale ceramsite and poor adhesion to asphalt, resulting in decreased water stability and dynamic stability. Comparative Example 5 uses unmodified asphalt, which lacks the polymer network formed by SBS, causing a sharp decrease in the mixture's resistance to flow deformation. Comparative Example 6 is not treated with silane coupling agent, and moisture easily penetrates the untreated ceramsite-asphalt interface, leading to adhesion failure and a sharp decrease in the freeze-thaw splitting ratio.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag, characterized in that: It contains the following ingredients: Slag ceramsite, modified asphalt, crushed stone, sand, mineral powder, and coupling agent; The density of the slag ceramsite is 600-1100 kg / m³. 3 Ceramsite with a compressive strength of 8-12 MPa, a particle size of ≤12 mm, and a water absorption rate of ≤5%.

2. The lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag according to claim 1, characterized in that: The modified asphalt is SBS modified asphalt; the method for preparing the SBS modified asphalt includes the following steps: A1. Heat the asphalt to 170-180℃, add SBS particles and aromatic oil compatibilizer and mix evenly; A2. Add 0.1-0.3% sulfur by weight of asphalt to the mixture obtained in step A1 and mix well. Maintain the temperature at 170-180℃ and stir at 50-100 rpm for 2-4 hours.

3. The lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag according to claim 2, characterized in that: The mass ratio of asphalt, SBS particles and aromatic oil compatibilizer in step A1 is 100:4.5-5.5:1.8-2.

5.

4. The lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag according to claim 1, characterized in that: The crushed stone has a particle size of 2-16 mm; the sand has a particle size of 0.3-4.75 mm.

5. The lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag according to claim 1, characterized in that: The mineral powder is limestone powder with a particle size of less than 0.075 mm.

6. The lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag according to claim 1, characterized in that: The coupling agent is silane coupling agent KH-550.

7. The lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag according to claim 1, characterized in that: The mass ratio of the slag ceramsite, modified asphalt, crushed stone, sand, and mineral powder is 25-30:4.5-5.5:5-10:15-20:8-10.

8. A method for preparing lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag, as described in any one of claims 1-6, characterized in that: Includes the following steps: (1) Mix the slag ceramsite with coupling agent KH-550; (2) Heat the modified asphalt to 160-170℃, and add the slag ceramsite, crushed stone, sand and mineral powder treated with coupling agent obtained in step (1) in sequence and mix evenly. (3) The mixture from step (2) is subjected to Marshall compaction at 145-155°C, and the void ratio is controlled to be 4-6%.

9. A method for preparing lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag, as described in claim 8, characterized in that: The mass ratio of slag ceramsite to silane coupling agent KH-550 is 100:0.5-1.

5.

10. The lightweight aggregate asphalt concrete based on ceramsite from waste incineration power plant slag as described in any one of claims 1-7, characterized in that: The thermal conductivity of the asphalt concrete is ≤0.4W / m·K.

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