Asphalt concrete anti-stripping agent

Abstract

The invention discloses an asphalt concrete anti-stripping agent which comprises the following components in parts by weight: 5-15 parts of fly ash sinking beads and 10-20 parts of carbide slag. The fly ash sinking beads comprise the following components in percentage by weight: 50-60% of silicon oxide, 30-40% of aluminum oxide and 1-10% of calcium oxide; the carbide slag comprises the following components in percentage by weight: 3-8% of silicon oxide, 1-3% of aluminum oxide and 50-70% of calcium oxide. According to the asphalt concrete anti-stripping agent provided by the invention, the fly ash sinking beads containing silicon oxide, aluminum oxide and calcium oxide and the carbide slag with high calcium oxide content are selected, the fly ash sinking beads have relatively high reaction activity, calcium aluminosilicate is generated under an alkaline condition, and the calcium aluminosilicate can be chemically bonded with asphalt; the stability of the asphalt concrete at high temperature and low temperature is enhanced, and the anti-stripping performance is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of petrochemical engineering, and particularly relates to an anti-stripping agent for asphalt concrete. Background Art

[0002] Asphalt concrete is widely used in water conservancy, hydropower and road construction. However, in different geographical environments, its performance faces different challenges. Especially in the northwest region of China, the climate is harsh, which poses higher requirements for the performance of asphalt concrete.

[0003] In the northwest region, the climate is arid with little rainfall, and the temperature difference between day and night is extremely large. The high temperature in summer can reach above 40°C, while the low temperature in winter can drop below -20°C. Such extreme temperature changes will generate large temperature stresses inside the asphalt concrete, resulting in a decrease in the adhesion between asphalt and aggregates. To improve the adhesion between aggregates and asphalt, a method of adding an anti-stripping agent to enhance the chemical bonding between asphalt and aggregates is usually adopted.

[0004] However, the commonly used anti-stripping agents at present are organic types, which have problems such as poor thermal stability and easy decomposition at high temperatures, and it is difficult to adapt to the high temperature difference environment in the northwest region. Summary of the Invention

[0005] To solve the above problems, the present invention discloses an anti-stripping agent for asphalt concrete.

[0006] The present invention discloses an anti-stripping agent for asphalt concrete, which comprises, by weight, 5 parts to 15 parts of fly ash cenospheres and 10 parts to 20 parts of carbide slag.

[0007] The fly ash cenospheres, by weight, comprise: 50% to 60% of silicon oxide, 30% to 40% of aluminum oxide, and 1% to 10% of calcium oxide.

[0008] The carbide slag, by weight, comprises: 3% to 8% of silicon oxide, 1% to 3% of aluminum oxide, and 50% to 70% of calcium oxide.

[0009] Preferably, the anti-stripping agent further comprises 0.05 parts to 0.2 parts of a polymer admixture.

[0010] Preferably, the anti-stripping agent further comprises 60 parts to 100 parts of tailings.

[0011] The fineness of the fly ash cenospheres, carbide slag and tailings all meets the requirement that the passing rate through a 45μm square-hole sieve is greater than 95%.

[0012] Preferably, the tailings, by weight, comprise 30 parts to 50 parts of lithium slag.

[0013] Preferably, the tailings, by weight, further comprise 10 parts to 20 parts of gold tailings.

[0014] Preferably, the tailings further include 20 to 30 parts by weight of lead-zinc tailings.

[0015] Preferably, the polymer admixture is at least one of diethanol monoisopropanolamine, methyldiethanolamine, and dopamine hydrochloride.

[0016] Preferably, the lithium slag includes, by weight: 40% to 60% of silicon oxide, 20% to 30% of aluminum oxide, 0% to 10% of calcium oxide, 0% to 20% of sodium oxide, and 0% to 20% of potassium oxide.

[0017] Preferably, the gold tailings include, by weight: 60% to 70% of silicon oxide, 10% to 20% of aluminum oxide, and 0% to 5% of calcium oxide.

[0018] Preferably, the lead-zinc tailings include, by weight: 40% to 50% of silicon oxide, 5% to 15% of aluminum oxide, 5% to 15% of iron oxide, 10% to 25% of calcium oxide, and 5% to 10% of magnesium oxide.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The asphalt concrete anti-stripping agent proposed by the present invention selects fly ash cenospheres containing silicon oxide, aluminum oxide, and calcium oxide, as well as carbide slag with a high calcium oxide content. Fly ash cenospheres have a high reaction activity and generate calcium silicate aluminate under alkaline conditions. Calcium silicate aluminate can chemically bond with asphalt, enhancing the stability of asphalt concrete at high and low temperatures and significantly improving the anti-stripping performance of asphalt concrete.

[0021] (2) Further, the high sphericity of fly ash cenospheres optimizes the dispersibility of the anti-stripping agent in asphalt concrete, solves the problem of easy agglomeration of traditional anti-stripping agents, and its "ball bearing" effect also improves the fluidity, high-temperature stability, low-temperature stability, and water resistance of asphalt concrete.

[0022] (3) The present invention also incorporates a variety of industrial tailings rich in chemical components such as silicon, aluminum, and calcium, which undergo chemical reactions in the alkaline environment provided by carbide slag to generate hydrated calcium silicate aluminate, thereby enhancing the asphalt viscosity and improving the anti-stripping performance, high-temperature stability, low-temperature stability, and water erosion resistance of asphalt concrete.

[0023] (4) The present invention uses a variety of industrial tailings to prepare the anti-stripping agent, which not only reduces the environmental burden but also avoids the pollution of harmful elements in industrial tailings to air, water, and soil.

[0024] (5) By carefully blending a variety of industrial tailings, such as highly reactive lithium slag and fly ash cenospheres with low-reactivity gold tailings and lead-zinc tailings, a complementary effect is formed to enhance the overall material properties. Calcium carbide slag, as an alkaline activator, promotes the chemical reactions among the tailings, generating a more stable and better-performing material;

[0025] (6) The main component of calcium carbide slag, calcium oxide, can stimulate the reaction activity of siliceous and aluminous tailings, generating products such as alkaline calcium silicoaluminate gel, filling the interfacial transition zone between asphalt and aggregates, improving the anti-stripping performance, and supplementing the calcium and alkalinity in the aggregates, improving the polarity of acidic aggregates, and promoting the bonding at the asphalt-aggregate interface;

[0026] (7) The present invention uses the rich mineral resources and their industrial tailings in the northwest region as the main raw materials, such as lithium slag, gold tailings, calcium carbide slag, lead-zinc tailings, and fly ash cenospheres, etc., which is convenient for local material procurement and reduces transportation costs;

[0027] (8) The present invention also adds a polymer admixture. Its organic functional groups such as hydroxyl, ethoxy, amino, phenolic hydroxyl, and carboxyl can complex the valuable metal ions in the tailings, enhance the reaction activity, promote the generation of products such as calcium silicoaluminate gel, fill the interfacial transition zone between asphalt and aggregates, and improve the anti-stripping performance. Further, functional groups such as amino, phenolic hydroxyl, and carboxyl can still act on the asphalt-aggregate interface after the reaction of silicon and aluminum elements, and further improve the anti-stripping performance of asphalt concrete by forming a chemical adsorption layer, reducing the interfacial tension, etc. Detailed implementation mode

[0028] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present invention.

[0029] The present invention discloses an anti-stripping agent for asphalt concrete. The anti-stripping agent includes 5 parts to 15 parts of fly ash cenospheres and 10 parts to 20 parts of calcium carbide slag by weight;

[0030] Preferably, in the present invention, x parts to x parts all represent the corresponding components by mass fraction; x% to x% all represent the corresponding components by mass percentage.

[0031] The fly ash cenospheres include, by weight: 50% to 60% of silicon dioxide, 30% to 40% of aluminum oxide, and 1% to 10% of calcium oxide;

[0032] The carbide slag, by weight, includes: 3% - 8% of silicon oxide, 1% - 3% of aluminum oxide, and 50% - 70% of calcium oxide. In the present invention, the carbide slag is selected as the alkaline activator, which can stimulate the chemical reaction activity of minerals, promote the chemical reactions among tailings, and thus generate a more stable and better-performing material.

[0033] Preferably, the anti-stripping agent further includes 0.05 - 0.2 parts of a polymer admixture.

[0034] Preferably, the polymer admixture is at least one of diethanol monoisopropanolamine, methyldiethanolamine, and dopamine hydrochloride.

[0035] Preferably, the anti-stripping agent further includes 60 - 100 parts of tailings;

[0036] The fineness of fly ash cenospheres, carbide slag, and tailings all meets the requirement that the passing rate through a 45μm square-hole sieve is greater than 95%. The fly ash cenospheres, carbide slag, and tailings with the selected particle sizes in the present invention can form a dense packing structure, reduce the porosity, and improve the density and strength of the anti-stripping agent.

[0037] In the present invention, the fly ash cenospheres have a fine particle structure and a high specific surface area, which enables them to fully contact the reaction medium and is beneficial to the progress of chemical reactions; in addition, the glass microspheres in the fly ash cenospheres have a smooth surface and a dense texture, which can improve the dispersibility of the anti-stripping agent in asphalt concrete and solve the problem of easy agglomeration of traditional anti-stripping agents; and when the fly ash cenospheres are added to asphalt concrete, they can play a "ball bearing" effect, improve the working properties such as the fluidity of asphalt concrete, and improve its high-temperature stability, low-temperature stability, and water resistance.

[0038] Preferably, the tailings, by weight, include 30 - 50 parts of lithium slag.

[0039] Preferably, the lithium slag, by weight, includes: 40% - 60% of silicon oxide, 20% - 30% of aluminum oxide, 0% - 10% of calcium oxide, 0% - 20% of sodium oxide, and 0% - 20% of potassium oxide.

[0040] Preferably, the tailings, by weight, further include 10 - 20 parts of gold tailings.

[0041] Preferably, the gold tailings, by weight, include: 60% - 70% of silicon oxide, 10% - 20% of aluminum oxide, and 0% - 5% of calcium oxide.

[0042] Preferably, the tailings, by weight, further include 20 - 30 parts of lead-zinc tailings.

[0043] Preferably, the lead-zinc tailings, by weight, include: 40% - 50% of silicon oxide, 5% - 15% of aluminum oxide, 5% - 15% of iron oxide, 10% - 25% of calcium oxide, and 5% - 10% of magnesium oxide.

[0044] By combining multiple types of tailings, the present invention can achieve the maximum utilization of resources and avoid the accumulation and waste of single tailings.

[0045] In the present invention, highly active lithium slag and fly ash cenospheres are used as the core materials of the reaction, which can provide more active sites for chemical reactions, promote the diffusion and contact of reactants. Although low-activity tailings (such as gold tailings and lead-zinc tailings) have low activity, their particles can be used as filling materials to fill the pores formed after the reaction of high-activity tailings, forming a dense structure, improving the compactness and mechanical properties of the material. Further, the addition of low-activity tailings can slow down the rapid progress of the reaction, avoid local stress concentration or structural defects caused by the too-fast reaction, thereby enhancing the uniformity and stability of the reaction. Moreover, the combination of high- and low-activity tailings is also conducive to the full utilization of tailings resources and cost reduction.

[0046] Preferably, the dosage of the anti-stripping agent is 1% - 3% of the weight of the asphalt concrete.

[0047] The following are several examples and comparative examples of the present invention:

[0048] Example 1

[0049] This example discloses an anti-stripping agent for asphalt concrete, which is prepared from 30 parts of lithium slag, 20 parts of gold tailings, 20 parts of carbide slag, 30 parts of lead-zinc tailings, 15 parts of fly ash cenospheres and 0.2 parts of polymer admixture by weight.

[0050] By mass percentage, the chemical composition of the lithium slag includes 40% silicon oxide, 20% aluminum oxide, 10% calcium oxide, and the total of sodium oxide and potassium oxide is 20%. The fineness of the lithium slag is less than 5% of the residue on a 45μm square-hole sieve.

[0051] By mass percentage, the chemical composition of the gold tailings includes 70% silicon oxide, 20% aluminum oxide, 5% calcium oxide. The fineness of the gold tailings is less than 5% of the residue on a 45μm square-hole sieve.

[0052] By mass percentage, the chemical composition of the carbide slag includes 8% silicon oxide, 3% aluminum oxide, 70% calcium oxide. The fineness of the carbide slag is less than 5% of the residue on a 45μm square-hole sieve.

[0053] By mass percentage, the chemical composition of the lead-zinc tailings includes 50% silicon oxide, 15% aluminum oxide, 15% iron oxide, 25% calcium oxide, 10% magnesium oxide. The fineness of the lead-zinc tailings is less than 5% of the residue on a 45μm square-hole sieve.

[0054] Fly ash cenospheres, by mass percentage, have chemical components including 60% silicon oxide, 40% aluminum oxide, and 10% calcium oxide. The fineness of fly ash cenospheres is such that the residue on a 45 µm square-hole sieve is less than 5%.

[0055] The polymer admixture is diethanolmonoisopropanolamine.

[0056] The dosage of the anti-stripping agent is 1% of the weight of the asphalt concrete. The test results of the anti-stripping performance of the asphalt concrete in this example are shown in Table 1.

[0057] Example 2

[0058] The difference from Example 1 is that the addition amount of the polymer admixture is 0.05 parts by weight.

[0059] The dosage of the anti-stripping agent is 1% of the weight of the asphalt concrete.

[0060] The test results of the anti-stripping performance of the asphalt concrete in this example are shown in Table 1.

[0061] Example 3

[0062] The difference from Example 1 is that the addition amount of the polymer admixture is 0.1 parts by weight.

[0063] The dosage of the anti-stripping agent is 1% of the weight of the asphalt concrete.

[0064] The test results of the anti-stripping performance of the asphalt concrete in this example are shown in Table 1.

[0065] Example 4

[0066] The difference from Example 1 is that the polymer admixture is a mixture of diethanolmonoisopropanolamine, methyldiethanolamine, and dopamine hydrochloride, and their weight ratio is 2:2:1.

[0067] The test results of the anti-stripping performance of the asphalt concrete in this example are shown in Table 1.

[0068] Comparative Example 1

[0069] The difference between this comparative example and Example 1 is that it does not contain gold tailings and lead-zinc tailings.

[0070] The test results of the anti-stripping performance of the asphalt concrete in this comparative example are shown in Table 1.

[0071] Comparative Example 2

[0072] The difference between this comparative example and Example 1 is that it does not contain lithium slag and fly ash cenospheres.

[0073] The test results of the anti-stripping performance of the asphalt concrete in this comparative example are shown in Table 1.

[0074] Comparative Example 3

[0075] The difference between this comparative example and Example 1 is that 15 parts of fly ash cenospheres are replaced by 15 parts of fly ash.

[0076] The test results of the anti-stripping performance of the asphalt concrete in this comparative example are shown in Table 1.

[0077] Comparative Example 4

[0078] The difference between this comparative example and Example 1 is that the dosage of the anti-stripping agent is 2% of the weight of the asphalt concrete.

[0079] The test results of the anti-stripping performance of the asphalt concrete in this comparative example are shown in Table 1.

[0080] Comparative Example 5

[0081] The difference between this comparative example and Example 1 is that the dosage of the anti-stripping agent is 3% of the weight of the asphalt concrete.

[0082] The test results of the anti-stripping performance of the asphalt concrete in this comparative example are shown in Table 1.

[0083] Table 1 Test Results of Anti-Stripping Performance of Asphalt Concrete

[0084]

[0085] In Table 1, the splitting strength ratio is used to measure the water stability of the asphalt concrete. The larger the splitting strength value, the better the water stability of the asphalt concrete; the mass stripping rate of asphalt by the boiling method is used to measure the anti-stripping performance of the asphalt concrete. The smaller the mass stripping rate of asphalt by the boiling method, the better the anti-stripping performance of the asphalt concrete. Combining Examples 1, 2, and 3, it can be seen that with the increase of the polymer admixture, the high-temperature stability of the asphalt concrete first decreases and then increases, the low-temperature stability gradually increases, and the anti-stripping performance first decreases and then increases. Considering the comprehensive cost, the range of the polymer admixture selected in the present invention is within 0.2 parts; combining Examples 1, Comparative Example 1, and Comparative Example 2, it can be seen that compared with simply adding high-activity tailings or low-activity tailings, the asphalt concrete added with the anti-stripping agent composed of the high- and low-activity tailings in the present invention has more excellent high- and low-temperature stabilities, strength, water stability, and anti-stripping performance; combining Example 1 and Comparative Example 3, it can be seen that compared with fly ash, the asphalt concrete added with fly ash cenospheres has stronger high- and low-temperature stabilities, anti-stripping performance, and water stability; combining Examples 1, Comparative Example 4, and Comparative Example 5, it can be seen that with the increase of the dosage of the anti-stripping agent, the high- and low-temperature stabilities and anti-stripping performance of the asphalt concrete gradually increase, but the effectiveness of the anti-stripping agent per unit weight gradually decreases, that is, the marginal diminishing effect of the improvement of the anti-stripping agent appears; comparing Example 1 and Example 4, it can be seen that mixing multiple polymer admixtures can significantly improve the high-temperature stability, low-temperature stability, strength, un-frozen and thawed splitting strength, and frozen and thawed splitting strength of the asphalt concrete.

[0086] Compared with the prior art, the present invention has the following beneficial effects:

[0087] (1) The present invention selects fly ash cenospheres including silicon oxide, aluminum oxide and calcium oxide, and carbide slag with a relatively high calcium oxide content; fly ash cenospheres have relatively high reactivity, and in an alkaline environment, calcium silicate aluminate is generated by reaction. Calcium silicate aluminate can chemically bond with asphalt and is stable both at elevated temperatures and low temperatures, which can effectively improve the anti-stripping performance of asphalt concrete;

[0088] (2) Further, fly ash cenospheres have a high sphericity, which can improve the dispersibility of the anti-stripping agent in asphalt concrete and solve the problem of easy agglomeration of traditional anti-stripping agents; moreover, when fly ash cenospheres are added to asphalt concrete, the "ball bearing" effect can be exerted to improve the working properties such as the fluidity of asphalt concrete, and improve its high-temperature stability, low-temperature stability and water resistance;

[0089] (3) The present invention selects a variety of industrial tailings containing chemical components such as silicon, aluminum and calcium, which can undergo chemical reactions in the alkaline environment provided by carbide slag to generate hydrated calcium silicate aluminate, thereby increasing the viscosity of asphalt and improving the anti-stripping performance, high-temperature stability, low-temperature stability and water erosion resistance of asphalt concrete;

[0090] (4) The present invention selects a variety of industrial tailings to prepare an anti-stripping agent, which can reduce the environmental load and avoid the pollution of air, water resources and soil resources by harmful elements in industrial tailings;

[0091] (5) The present invention selects a variety of industrial tailings and through formulation, the relatively high-activity lithium slag and fly ash cenospheres are combined with the relatively low-activity gold tailings and lead-zinc tailings, which can form a complementary effect to improve the performance of the overall material. Carbide slag, as an alkaline activator, can stimulate the chemical reaction activity of minerals and promote the chemical reaction between tailings, thereby generating a more stable and better-performing material;

[0092] (6) The carbide slag selected by the present invention, whose main component is calcium oxide, can stimulate the reaction activity of siliceous tailings to generate alkaline hydrated calcium silicate aluminate gel and other products to fill the interfacial transition zone between asphalt and aggregate, improving the anti-stripping performance of asphalt concrete; and it can supplement the calcium component and alkalinity in the aggregate, improve the polarity of acidic aggregates, and promote the bonding between the asphalt and aggregate interfaces in asphalt concrete, further enhancing the anti-stripping performance;

[0093] (7)The anti-stripping agent for asphalt concrete of the present invention uses the rich mineral resources and industrial tailings in the northwest region as the main raw materials, including lithium slag discharged from the lithium ore industry, gold tailings discharged after gold extraction, carbide slag after acetylene gas is obtained by hydrolysis of calcium carbide, lead-zinc tailings discharged after extraction of lead and zinc metals, and the bead components in fly ash tailings discharged from coal power plants, etc., which is convenient for local material collection and reduces transportation costs;

[0094] (8)The anti-stripping agent for asphalt concrete of the present invention adds a polymer admixture. Through the organic functional groups such as hydroxyl, ethoxy, amino, phenolic hydroxyl, and carboxyl in the polymer admixture, the valuable metal ions (such as aluminum, iron, calcium, magnesium, etc.) in the tailings are complexed to enhance their reaction activity and promote the formation of products such as calcium silicoaluminate gel, which fills the interfacial transition zone between asphalt and aggregate and improves the anti-stripping performance of asphalt concrete. Further, in the present invention, the organic functional groups such as amino, phenolic hydroxyl, and carboxyl in the polymer admixture will not be consumed after accelerating the reaction of silicon and aluminum elements, but can continue to enter the asphalt-aggregate interface and improve the anti-stripping performance of asphalt concrete by forming a chemical adsorption layer and reducing the interfacial tension, etc.

[0095] The above are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, makes some changes or modifications using the technical content disclosed above, which are equivalent to equivalent embodiments and all fall within the scope of the technical solution.

Claims

1. An asphalt concrete anti-stripping agent, characterized in that: The anti-stripping agent comprises 5 to 15 parts of fly ash beads and 10 to 20 parts of carbide slag by weight; The fly ash beads include, by weight, 50% to 60% silicon oxide, 30% to 40% aluminum oxide, and 1% to 10% calcium oxide; The carbide slag comprises, by weight, 3% to 8% silicon oxide, 1% to 3% aluminum oxide, and 50% to 70% calcium oxide.

2. The asphalt concrete anti-stripping agent according to claim 1, characterized in that The anti-stripping agent also includes 0.05 to 0.2 parts of a polymer additive.

3. The asphalt concrete anti-stripping agent according to claim 1, characterized in that: The anti-stripping agent also includes 60 to 100 parts of tailings; The fineness of the fly ash beads, carbide slag and tailings all meets the requirement that the passing rate of the 45µm square hole sieve is greater than 95%.

4. The asphalt concrete anti-stripping agent according to claim 3, characterized in that: The tailings include 30 to 50 parts of lithium slag by weight.

5. The asphalt concrete anti-stripping agent according to claim 4, characterized in that: The tailings also include 10 to 20 parts of gold tailings by weight.

6. The asphalt concrete anti-stripping agent according to claim 5, characterized in that: The tailings also include 20 to 30 parts of lead-zinc tailings by weight.

7. The asphalt concrete anti-stripping agent according to claim 2, characterized in that: The polymer additive is at least one of diethanol monoisopropanolamine, methyldiethanolamine and dopamine hydrochloride.

8. The asphalt concrete anti-stripping agent according to claim 4, characterized in that: The lithium slag comprises, by weight, 40% to 60% silicon oxide, 20% to 30% aluminum oxide, 0% to 10% calcium oxide, 0% to 20% sodium oxide and 0% to 20% potassium oxide.

9. The asphalt concrete anti-stripping agent according to claim 5, characterized in that: The gold tailings include, by weight, 60% to 70% silicon oxide, 10% to 20% aluminum oxide, and 0% to 5% calcium oxide.

10. The asphalt concrete anti-stripping agent according to claim 6, characterized in that: The lead-zinc tailings include, by weight, 40% to 50% silicon oxide, 5% to 15% aluminum oxide, 5% to 15% iron oxide, 10% to 25% calcium oxide, and 5% to 10% magnesium oxide.

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