A steel slag-based pavement composite material and its preparation method

Abstract

The application discloses a steel slag-based pavement composite material and a preparation method thereof, and relates to the technical field of road building materials. The preparation method of the steel slag-based pavement composite material comprises the following steps: uniformly mixing steel slag fine aggregate, steel slag coarse aggregate and asphalt, cooling to room temperature, and obtaining steel slag-based asphalt concrete; uniformly mixing steel slag micro powder, blast furnace slag powder, an expanding agent, a water reducing agent, an interface reinforcing agent and water, and obtaining steel slag micro powder grouting material; injecting the steel slag micro powder grouting material into the voids of the steel slag-based asphalt concrete, and obtaining the steel slag-based pavement composite material after setting. The steel slag-based pavement composite material is prepared by taking the steel slag-based asphalt concrete as a matrix, injecting the steel slag micro powder grouting material into the voids of the steel slag-based asphalt concrete, and adopting amino silicon oil and methyl acrylamide dopamine to enhance the bonding strength of the interface between the steel slag micro powder grouting material and the steel slag-based asphalt concrete, so that a pavement composite material with high deformation resistance and high stability is obtained.

Description

Technical Field

[0001] This invention relates to the field of road construction materials technology, and in particular to a steel slag-based pavement composite material and its preparation method. Background Technology

[0002] Existing highway pavements can be mainly divided into two categories: cement concrete pavements and asphalt concrete pavements. However, both types of pavement materials have some drawbacks. For example, cement concrete pavements are rigid pavement materials, resulting in slow traffic flow. Furthermore, the hardened cement is brittle and prone to cracking, breakage, chipping, and voids under external shear stress. Asphalt concrete pavements, on the other hand, are flexible pavement materials. In high summer temperatures, they soften, reducing the pavement's elastic modulus and making them susceptible to permanent deformation under external loads, leading to rutting. Additionally, asphalt materials are prone to aging and decreased bonding capacity under the combined effects of light, heat, atmosphere, and rainwater, resulting in reduced durability and increased cracking. Meanwhile, my country produces a huge amount of steel slag, with approximately 70% remaining unused and occupying vast amounts of land for long-term stockpiling.

[0003] Therefore, it is of great significance to develop a steel slag-based pavement composite material that comprehensively utilizes asphalt concrete and cement concrete, addressing the shortcomings of existing pavement materials and steel slag solid waste resource utilization technologies. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, this invention provides a steel slag-based pavement composite material and its preparation method. By using steel slag-based asphalt concrete as a matrix, steel slag micro-powder grout is injected into the voids of the matrix. Amino silicone oil and methacrylamide dopamine are used to significantly enhance the interfacial bonding strength between the steel slag micro-powder grout and the asphalt concrete, resulting in a steel slag-based pavement composite material with high deformation resistance and stability. Specifically, this is achieved through the following techniques:

[0005] In a first aspect, the present invention provides a method for preparing a steel slag-based pavement composite material, comprising the following steps:

[0006] S1. Steel slag fine aggregate, steel slag coarse aggregate, and asphalt are mixed evenly at 170-175℃ and cooled to room temperature to obtain steel slag-based asphalt concrete; steel slag powder, blast furnace slag powder, expanding agent, water-reducing agent, and interface reinforcing agent are mixed evenly, and then water is added at a water-cement ratio of 0.3-0.5, and mixed evenly to obtain steel slag powder grouting material; the interface reinforcing agent includes amino silicone oil and methacrylamide dopamine;

[0007] S2. The steel slag micro-powder grout is injected into the voids of the steel slag-based asphalt concrete. After solidification, a steel slag-based pavement composite material is obtained.

[0008] Furthermore, the porosity of the aforementioned steel slag-based asphalt concrete is 22-28%.

[0009] Furthermore, in the above-mentioned interface reinforcing agent, the mass ratio of amino silicone oil to methacrylamide dopamine is 3:(2-2.5).

[0010] Furthermore, in the aforementioned steel slag-based asphalt concrete, the mass fraction of fine steel slag aggregate is 10–20 parts, the mass fraction of coarse steel slag aggregate is 75–90 parts, and the mass fraction of asphalt is 3–5 parts.

[0011] Furthermore, in the above-mentioned steel slag micro powder grouting material, the mass fraction of steel slag micro powder is 60-70 parts, blast furnace slag powder is 30-40 parts, expansion agent is 0.5-1 part, water-reducing agent is 0.5-1 part, and interface reinforcing agent is 0.1-0.2 parts.

[0012] Furthermore, in the aforementioned steel slag-based asphalt concrete, the particle size of the fine steel slag aggregate is 0.15 mm to 2.36 mm, and the particle size of the coarse steel slag aggregate is 2.36 mm to 13.2 mm.

[0013] Furthermore, in the above-mentioned steel slag micro powder grouting material, the particle size of the steel slag micro powder is less than 0.15 mm, and the particle size of the blast furnace slag powder is less than 250 μm.

[0014] Furthermore, the aforementioned water-reducing agent includes at least one of naphthalene-based water-reducing agents, polycarboxylate water-reducing agents, and lignin water-reducing agents.

[0015] Furthermore, the aforementioned expanding agent is a plastic expanding agent.

[0016] In a second aspect, the present invention provides a steel slag-based pavement composite material prepared by the above-described preparation method.

[0017] This invention uses large-pore steel slag-based asphalt concrete as the matrix and injects steel slag micro-powder grout into the pores of the matrix, excellently combining the material advantages of both rigid and flexible pavement materials. However, the interfacial bonding strength between the steel slag-based asphalt concrete and the steel slag micro-powder grout is the core key to achieving this effect. Therefore, this invention adds an interfacial reinforcing agent composed of amino silicone oil and methacrylamide dopamine. On the one hand, the Si-OH groups generated during the hydrolysis of amino silicone oil form covalent bonds with the CSH groups of the hydration products of the steel slag micro-powder grout through a condensation dehydration reaction. Simultaneously, the amino groups of the amino silicone oil undergo a condensation reaction with the active groups in the asphalt, resulting in a good interfacial bond between the hydration products CSH and the asphalt, allowing the steel slag-based asphalt concrete and the steel slag micro-powder grout to bond tightly together. On the other hand, by using methacrylamide dopamine in combination with amino silicone oil, the interfacial bonding strength between the steel slag-based asphalt concrete and the steel slag micro-powder grout is significantly improved.

[0018] Compared with the prior art, the advantages of the present invention are:

[0019] 1. By using porous steel slag-based asphalt concrete as the matrix and injecting steel slag micro powder grout into the pores, the material advantages of rigid pavement materials and flexible pavement materials are excellently combined. Furthermore, amino silicone oil and methacrylamide dopamine are used to enhance the bonding strength of the interface between the steel slag micro powder grout and asphalt concrete, resulting in a steel slag-based pavement composite material with strong deformation resistance and high stability.

[0020] 2. This invention uses steel slag as a cementing material and aggregate, which promotes the large-scale resource reuse of steel slag. It is environmentally friendly, low in cost, and the preparation process of this road composite material is simple, non-volatile, non-polluting, and non-toxic. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The method for preparing steel slag-based pavement composite material provided by the present invention includes the following steps:

[0023] S1. Steel slag fine aggregate, steel slag coarse aggregate, and asphalt are mixed evenly at 170-175℃ and cooled to room temperature to obtain steel slag-based asphalt concrete; steel slag powder, blast furnace slag powder, expanding agent, water-reducing agent, and interface reinforcing agent are mixed evenly to obtain steel slag powder cementitious material, and then water is added at a water-cement ratio of 0.3-0.5 and mixed evenly to obtain steel slag powder grouting material; the interface reinforcing agent includes amino silicone oil and methacrylamide dopamine;

[0024] S2. The steel slag micro-powder grout is injected into the voids of the steel slag-based asphalt concrete. After solidification, a steel slag-based pavement composite material is obtained.

[0025] The mass ratio of the above-mentioned amino silicone oil to methacrylamide dopamine is 3:(2-2.5); in steel slag-based asphalt concrete, the mass fraction of fine steel slag aggregate is 10-20 parts, coarse steel slag aggregate is 75-90 parts, and asphalt is 3-5 parts; in steel slag micro powder grouting material, the mass fraction of steel slag micro powder is 60-70 parts, blast furnace slag powder is 30-40 parts, expansion agent is 0.5-1 part, water-reducing agent is 0.5-1 part, and interface reinforcing agent is 0.1-0.2 parts.

[0026] The main chemical compositions of each raw material in the following examples and comparative examples are shown in Table 1 below:

[0027] Table 1. Main chemical composition of raw materials (wt%)

[0028] raw material <![CDATA[SiO2]]> <![CDATA[Fe2O3]]> <![CDATA[Al2O3]]> CaO MgO MnO other Steel slag fine aggregate 19.91 18.55 4.16 42.06 6.50 5.42 4.33 Steel slag coarse aggregate 18.86 19.62 4.04 44.51 6.74 4.43 1.77 Steel slag powder 19.12 19.54 4.36 43.44 6.66 4.81 2.03 Blast furnace slag powder 27.91 3.64 17.34 37.91 8.32 0.26 4.56

[0029] In the following examples and comparative examples, the particle size of the fine steel slag aggregate is 0.15 mm to 2.36 mm, the particle size of the coarse steel slag aggregate is 2.36 mm to 13.2 mm, the particle size of the steel slag powder is less than 0.15 mm, and the particle size of the blast furnace slag powder is less than 250 μm.

[0030] For ease of comparison, the specific dosages disclosed in the following embodiments and comparative examples are as follows:

[0031] Example 1

[0032] The preparation of the steel slag-based pavement composite material in this embodiment includes the following steps: First, 10 parts of fine steel slag aggregate, 87 parts of coarse steel slag aggregate and 3 parts of asphalt (Liaoning Oilfield 70# road petroleum asphalt) are mixed and stirred at 170°C, cooled to room temperature, and steel slag-based asphalt concrete with a porosity of 22.4% is obtained and laid flat on a level ground.

[0033] Secondly, 60 parts of steel slag powder, 40 parts of blast furnace slag powder, 0.5 parts of azo plastic expansion agent, 0.5 parts of polycarboxylate superplasticizer with a water reduction rate of 35%, and 0.2 parts of interface reinforcing agent (amino silicone oil and methacrylamide dopamine mixed at a mass ratio of 3:2) are uniformly mixed to prepare steel slag powder cementitious material. Then, water is added at a water-cement ratio of 0.3 and mixed evenly to prepare steel slag powder grouting material.

[0034] Finally, the steel slag micro-powder grout is injected into the voids of the steel slag-based asphalt concrete. After solidification, the steel slag-based pavement composite material is obtained.

[0035] Example 2

[0036] The preparation of the steel slag-based pavement composite material in this embodiment includes the following steps: First, 20 parts of fine steel slag aggregate, 75 parts of coarse steel slag aggregate and 5 parts of asphalt (Liaoning Oilfield 70# road petroleum asphalt) are mixed and stirred at 175°C, cooled to room temperature, and steel slag-based asphalt concrete with a porosity of 23.6% is obtained and laid flat on a level ground.

[0037] Secondly, 70 parts of steel slag powder, 30 parts of blast furnace slag powder, 1 part of sulfoaluminate plastic expansion agent, 1 part of naphthalene-based water-reducing agent with a water reduction rate of 20%, and 0.1 parts of interface reinforcing agent (amino silicone oil and methacrylamide dopamine mixed at a mass ratio of 3:2.2) are uniformly mixed to prepare steel slag powder cementitious material. Then, water is added at a water-cement ratio of 0.5 and mixed evenly to prepare steel slag powder grouting material.

[0038] Finally, the steel slag micro-powder grout is injected into the voids of the steel slag-based asphalt concrete. After solidification, the steel slag-based pavement composite material is obtained.

[0039] Example 3

[0040] The preparation of the steel slag-based pavement composite material in this embodiment includes the following steps: First, 18 parts of fine steel slag aggregate, 87 parts of coarse steel slag aggregate and 5 parts of asphalt (Liaoning Oilfield 70# road petroleum asphalt) are mixed and stirred at 175°C, cooled to room temperature, and steel slag-based asphalt concrete with a porosity of 22.1% is obtained and laid flat on a level ground.

[0041] Secondly, 65 parts of steel slag powder, 35 parts of blast furnace slag powder, 0.7 parts of magnesium oxide (plastic expansion agent), 0.7 parts of lignin water-reducing agent with a water reduction rate of 10%, and 0.15 parts of interface reinforcing agent (amino silicone oil and methacrylamide dopamine mixed at a mass ratio of 3:2.5) are uniformly mixed to prepare steel slag powder cementitious material. Then, water is added at a water-cement ratio of 0.5 and mixed evenly to prepare steel slag powder grouting material.

[0042] Finally, the steel slag micro-powder grout is injected into the large voids of the steel slag-based asphalt concrete. After solidification, the steel slag-based pavement composite material is obtained.

[0043] Comparative Example 1

[0044] The only difference between the steel slag-based pavement composite material in this comparative example and Example 1 is that the amount of interface reinforcing agent remains the same and it is entirely composed of amino silicone oil.

[0045] Comparative Example 2

[0046] The only difference between the steel slag-based pavement composite material in this comparative example and Example 1 is that the amount of interface reinforcing agent remains the same and it is entirely composed of methacrylamide dopamine.

[0047] Comparative Example 3

[0048] The only difference between the steel slag-based pavement composite material in this comparative example and Example 1 is that polydimethylsiloxane is used instead of amino silicone oil in the interface reinforcing agent.

[0049] Comparative Example 4

[0050] The only difference between the steel slag-based pavement composite material in this comparative example and Example 1 is that sodium carboxymethyl cellulose is used instead of methacrylamide dopamine in the interface reinforcing agent.

[0051] Comparative Example 5

[0052] This comparative example uses commercially available steel slag-based asphalt concrete with the following mix proportions: steel slag of different particle sizes (9.5–16 mm, 4.75–9.5 mm, 2.36–4.75 mm, and 0–2.36 mm) mixed with limestone powder in a mass ratio of 21:25:12:39:3, with aggregate accounting for 95% and asphalt accounting for 5%.

[0053] The performance of the steel slag-based pavement composite materials obtained in Examples 1-3 and Comparative Examples 1-4 was tested. The test methods were in accordance with the standard JT-T 1238-2019 Cement-based Grouting Materials for Semi-flexible Mixtures. The test results are shown in Table 2 below:

[0054] Table 2 Performance Test Results

[0055]

[0056] As can be seen from the data in Table 2, the steel slag-based pavement composite material prepared by this invention has excellent performance in terms of Marshall stability, high temperature stability, residual stability ratio, freeze-thaw splitting ratio, and low temperature beam failure strain. This indicates that the steel slag-based pavement composite material combines the advantages of rigid pavement materials and flexible pavement materials, and has the advantages of strong deformation resistance and high stability.

[0057] Comparative Examples 1 and 2 did not use amino silicone oil and methacrylamide dopamine simultaneously as interface reinforcing agents. Comparative Example 3 used aminosilane instead of amino silicone oil, and Comparative Example 4 used sodium carboxymethyl cellulose instead of methacrylamide dopamine. Their deformation resistance and stability were not as good as those of Example 1. This shows that only by using amino silicone oil and methacrylamide dopamine simultaneously can the bonding effect of the interface between steel slag-based asphalt concrete and steel slag micro powder grouting material be the best.

[0058] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A method for preparing a steel slag-based pavement composite material, characterized by, The method comprises the following steps: S1, uniformly mixing steel slag fine aggregate, steel slag coarse aggregate and asphalt at 170-175 DEG C, and cooling to room temperature to obtain steel slag-based asphalt concrete; uniformly mixing steel slag powder, blast furnace slag powder, expansion agent, water reducing agent, interface reinforcing agent and water to obtain steel slag powder grouting material; the interface reinforcing agent comprises amino silicone oil and methacrylamide dopamine; S2, injecting the steel slag powder grouting material into the voids of the steel slag-based asphalt concrete, and obtaining steel slag-based pavement composite material after setting.

2. The production method according to claim 1, characterized by, The steel slag-based asphalt concrete has a porosity of 22-28%.

3. The preparation method according to claim 1, characterized in that, In the interface reinforcing agent, the mass ratio of the amino silicone oil to the methacrylamide dopamine is 3:(2-2.5).

4. The production method according to claim 1, characterized by, In the steel slag-based asphalt concrete, the steel slag fine aggregate is 10-20 parts, the steel slag coarse aggregate is 75-90 parts, and the asphalt is 3-5 parts.

5. The preparation method according to claim 1, characterized in that, In the steel slag powder grouting material, the steel slag powder is 60-70 parts, the blast furnace slag powder is 30-40 parts, the expansion agent is 0.5-1 part, the water reducing agent is 0.5-1 part, and the interface reinforcing agent is 0.1-0.2 part.

6. The method of claim 1, wherein, In the steel slag-based asphalt concrete, the particle size of the steel slag fine aggregate is 0.15-2.36 mm, and the particle size of the steel slag coarse aggregate is 2.36-13.2 mm.

7. The preparation method according to claim 1, characterized in that, In the steel slag powder grouting material, the particle size of the steel slag powder is less than 0.15 mm, and the particle size of the blast furnace slag powder is less than 250 μm.

8. The method of claim 1, wherein, The water reducing agent comprises at least one of a naphthalene series water reducing agent, a polycarboxylic acid water reducing agent and a lignin water reducing agent.

9. The method of claim 1, wherein, The expansion agent is a plastic expansion agent.

10. Steel slag-based pavement composite material prepared by the method according to any one of claims 1-9.

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