A low-oil-aggregate ratio steel slag asphalt concrete and its preparation method
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-03
- Publication Date
- 2026-08-14
AI Technical Summary
[0005]本发明的主要目的在于，针对现有技术存在的问题和不足，提供一种低油石比钢渣沥青混凝土，针对性地解决钢渣表面多孔等问题，有效抑制钢渣骨料安定性，显著降低钢渣沥青混凝土的油石比，用于降低钢渣沥青混凝土的综合成本，并且可以有效减少钢渣骨料缝隙中的水分，提升沥青与石料的黏附性，推动钢渣在道路中的应用
1）本发明提供了一种低孔隙率的钢渣骨料，可采用价格相对较低的浆料以较小代价有效填充钢渣颗粒的空隙，钢渣骨料颗粒表面的空隙经复合浆料填充后，可进一步促进降低沥青混凝土的油石比。
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of building materials technology, specifically relating to a low-oil-stone ratio steel slag asphalt concrete and its preparation method. Background Technology
[0002] Asphalt concrete, commonly known as asphalt concrete, is typically made by mixing aggregates with specific gradations, crushed stone or crushed gravel, stone chips or sand, mineral powder, etc., with a certain proportion of road asphalt materials under strictly controlled conditions. Steel slag has lower Los Angeles abrasion and crushing values than natural aggregates, while also having a higher polishing value. The high strength of steel slag gives it excellent wear resistance, and the anti-skid coefficient of asphalt pavement decreases slowly, improving vehicle driving safety.
[0003] However, steel slag aggregate has a higher water absorption rate than natural stone. Egesi et al. believe that the water absorption rate of aggregate represents the number of open pores on the aggregate surface; the higher the water absorption rate, the worse its freeze-thaw resistance under cold conditions. Furthermore, aggregates with high water absorption rates lead to a larger amount of asphalt in asphalt mixtures. Therefore, the water absorption rate of aggregates used in asphalt mixtures should be below 5% to reduce the cost of asphalt pavements. High-quality aggregates should have a low water absorption rate (≤1%). Chen et al.'s research mentioned that the water absorption rate of most converter steel slag is about 4-6 times that of granite, with only a small portion of high-quality converter steel slag having a water absorption rate not much different from that of limestone aggregate. The water absorption rate of converter steel slag varies with particle size; smaller particle sizes of steel slag have higher water absorption rates.
[0004] Steel slag asphalt concrete is a new type of asphalt concrete that uses steel slag to replace natural stone and sand aggregates. Compared to natural aggregates such as basalt aggregates, steel slag aggregates have richer particle characteristics, such as more pronounced angularity and a rougher surface texture. These advantages provide more support points after the asphalt concrete skeleton structure is formed. However, compared to conventional limestone asphalt concrete, steel slag asphalt concrete is usually designed with a relatively high asphalt-aggregate ratio. This is mainly because the surface of steel slag typically has micropores, exhibiting a loose and porous structure, which has a significant adsorption effect on asphalt, making steel slag uneconomical in the preparation of low-grade asphalt pavements. In addition, moisture on the surface of asphalt and steel slag aggregates forms a water film, hindering direct contact between asphalt and aggregates, making it difficult for asphalt to fully coat the stone surface. When water evaporates, it may disrupt the continuity of the asphalt film, reducing adhesion and making the mixture prone to peeling, loosening, and other defects during use. The presence of moisture also reduces the strength and stability of the mixture, diluting the asphalt concentration, thinning the asphalt film, and weakening the cohesion of the mixture. In low-temperature environments, the expansion of frozen water may cause micro-cracks inside the stone, further reducing its strength. Summary of the Invention
[0005] The main objective of this invention is to address the problems and shortcomings of existing technologies by providing a low asphalt-aggregate ratio steel slag asphalt concrete. This invention specifically solves problems such as the porosity of the steel slag surface, effectively inhibits the stability of steel slag aggregate, significantly reduces the asphalt-aggregate ratio of steel slag asphalt concrete, thereby reducing the overall cost of steel slag asphalt concrete. Furthermore, it can effectively reduce the moisture in the gaps of steel slag aggregate, improve the adhesion between asphalt and aggregate, and promote the application of steel slag in roads.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A low-oil-aggregate ratio steel slag asphalt concrete comprises the following components and their respective weight percentages: 61-66 parts modified steel slag aggregate, 2-4 parts steel slag powder, 4-4.5 parts asphalt, and 30-35 parts crushed stone; wherein the modified steel slag aggregate is obtained by coating the steel slag aggregate with a composite slurry, the composite slurry comprising mineral powder, steel slag powder, gypsum powder, early-strength agent, water-repellent agent, heat-resistant adhesive, and water.
[0007] Furthermore, the asphalt-aggregate ratio of the steel slag asphalt concrete is 3.9-5%.
[0008] In the above scheme, the particle size of the modified steel slag aggregate is 0-10mm.
[0009] In the above scheme, the particle size of the crushed stone is 10-15mm.
[0010] In the above scheme, the asphalt is SBS modified asphalt, with a softening point of not less than 85℃, a ductility of more than 40cm at 5℃, an elastic recovery rate of more than 95%, and after a 48-hour segregation test, the difference in softening point between the upper and lower sections is less than 2.0℃, showing excellent high and low temperature performance and storage stability.
[0011] In the above scheme, the components and their weight percentages in the composite slurry include: 15-20 parts mineral powder, 2-6 parts steel slag powder, 3-7 parts gypsum powder, 0.1-0.3 parts early strength agent, 0.3-0.7 parts water repellent agent, 0.1-0.3 parts warm wheel adhesive, and 70-80 parts water.
[0012] Furthermore, the preparation method of the composite slurry includes the following steps: First, the mineral powder, steel slag powder, gypsum powder, early strength agent, water repellent agent and a portion of water (40-60%) weighed in proportion are mixed; the warm wheel adhesive is made into powder and added to the remaining water (ratio about 1:350-400), the water temperature is controlled at 30-40℃, and it is continuously stirred to make it evenly dispersed; finally, the two mixtures are mixed to obtain the composite slurry, and the slurry fluidity is 160-200mm.
[0013] In the above scheme, the mineral powder is grade S95 or higher, with a specific surface area of 400-420 m². 2 / kg.
[0014] In the above scheme, the specific surface area of the steel slag powder is 300-350 m². 2 / kg.
[0015] In the above scheme, the gypsum powder is made by drying and grinding desulfurized gypsum, and has a specific surface area of not less than 300 m². 2 / kg.
[0016] In the above scheme, the early strength agent can be one or more of sodium chloride, calcium chloride, potassium chloride, etc.
[0017] In the above scheme, the hydrophobic agent is selected from siloxane or methylsilicate hydrophobic agents.
[0018] In the above scheme, the warm wheel adhesive is an industrial-grade warm wheel adhesive, which is a bio-based polymer widely used in food, petroleum, building materials and other fields.
[0019] In the above scheme, the particle size of the steel slag aggregate is 0-10mm.
[0020] Furthermore, the steel slag aggregate is subjected to iron selection, crushing, washing, and screening before use.
[0021] In the above scheme, the mass ratio of the composite slurry to the steel slag aggregate is 8-10:1.
[0022] In the above scheme, the coating process includes: mixing the composite slurry and steel slag aggregate, then loosely stacking them and allowing them to solidify.
[0023] Furthermore, the stirring speed is 240-300 r / min, the stirring time is 20-40 s, and after completion, the surface of the aggregate is completely covered with slurry.
[0024] Furthermore, the aggregate coated with slurry is loosely piled up and left to stand for 30-36 hours until the slurry has completely solidified, resulting in modified steel slag aggregate with low porosity.
[0025] The above-mentioned method for preparing low-oil-aggregate ratio steel slag asphalt concrete includes the following steps: 1) Weigh the raw materials according to the proportions. The raw materials and their weight percentages include: 61-66 parts of modified steel slag aggregate, 2-4 parts of steel slag powder, 4-4.5 parts of asphalt, and 30-35 parts of crushed stone. 2) First, the weighed crushed stone is mixed with the modified steel slag aggregate, then steel slag powder is added to the mixed aggregate, and finally asphalt is added and mixed. The mixture is then heated to obtain the low asphalt-aggregate ratio steel slag asphalt concrete.
[0026] In the above scheme, the heating treatment is carried out at a temperature of 150-170℃ for a time of 30-50 seconds.
[0027] Compared with the prior art, the beneficial effects of the present invention include: 1) This invention provides a steel slag aggregate with low porosity, which can effectively fill the voids of steel slag particles with relatively low cost using a relatively inexpensive slurry. After the voids on the surface of the steel slag aggregate particles are filled by the composite slurry, it can further promote the reduction of the asphalt-aggregate ratio of asphalt concrete.
[0028] 2) This invention coats the surface of steel slag aggregate with a low-cost composite slurry, which can effectively fill the voids in the steel slag aggregate. During the preparation of the slurry, the water-repellent agent introduced makes the slurry surface oleophilic, which can better contact with asphalt and ensure the adhesion between steel slag and asphalt.
[0029] 3) The slurry used in this invention is made by grinding solid waste and mixing it with water. It can effectively utilize large quantities of solid waste. During the mixing process, the water in the steel slag aggregate is fully absorbed to form a slurry. After standing, the water in the steel slag aggregate is fully absorbed, eliminating problems such as reduced adhesion between asphalt and aggregate caused by excessive water.
[0030] 4) The addition of warm roller adhesive and early strength agent can promote the improvement of slurry consistency and strength, and effectively coat the surface of aggregate particles, avoiding problems such as low viscosity caused by segregation and resulting in little decrease in oil-aggregate ratio. Detailed Implementation
[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0032] In the following examples, the mineral powder used is Wuxin S95 grade mineral powder with a specific surface area of 421 m². 2 / kg; the steel slag powder used was provided by Baowu Environmental Science & Technology Investment Co., Ltd., with a specific surface area of 315m². 2 / kg.
[0033] The gypsum powder is made by drying and grinding desulfurized gypsum, and has a specific surface area of 312 m². 2 / kg.
[0034] The particle size of the steel slag aggregate used is 0-10mm.
[0035] The early strength agent used is a mixture of sodium chloride and potassium chloride in a 1:1 mass ratio.
[0036] The water-repellent agent used is FJ80, a silicone oil-based water-repellent agent provided by Jiangsu Fujilia Building Materials Co., Ltd.
[0037] The silicone rubber used is an industrial-grade silicone rubber thickener provided by Hubei Mingtuo Biotechnology Co., Ltd.
[0038] The asphalt used is No. 70 or No. 90 road asphalt.
[0039] Examples 1-3 The preparation method of low asphalt-aggregate ratio steel slag asphalt concrete described in Examples 1-3 includes the following steps: 1) The raw materials were weighed according to the AC-13 mixing ratio, as detailed in Table 1; The preparation method of 0-10mm modified steel slag aggregate includes the following steps: weigh mineral powder, steel slag powder, gypsum powder and water-repellent agent according to the proportion (see Table 2), stir until fully mixed; gradually add the powder to the weighed water, mix evenly, and obtain composite slurry; Steel slag aggregate and composite slurry were mixed at a mass ratio of 9:1 for 30 seconds. After mixing, the aggregate surface was completely covered with slurry. The slurry-coated aggregate was then loosely piled up and left to stand for 36 hours until the slurry solidified, resulting in modified steel slag aggregate with low porosity. 2) Mix natural stone with modified steel slag aggregate, then add steel slag powder to the mixed aggregate, and finally add asphalt and mix. Heat the mixture at a temperature of 150-170℃ for 30-50 seconds to obtain the low asphalt-aggregate ratio steel slag asphalt concrete.
[0040] Comparative Example 1 A steel slag asphalt concrete is prepared in a manner largely the same as in Example 1, except that the steel slag aggregate is not modified by the slurry coating method described in this invention; instead, the modified steel slag aggregate described in this invention is replaced with a corresponding steel slag aggregate.
[0041] Comparative Example 2 A steel slag asphalt concrete is prepared in a manner similar to that of Example 1, except that no water-repellent agent is added to the composite slurry.
[0042] Comparative Example 3 A steel slag asphalt concrete is prepared in a manner similar to that of Example 1, except that the composite slurry does not contain heat-generating adhesive.
[0043] Comparative Example 4 A steel slag asphalt concrete is prepared in a manner similar to that of Example 1, except that the steel slag aggregate does not contain an early-strength agent in the grouting method described in this invention.
[0044] Table 1 AC-13 Mixing Proportions (by mass percentage)
[0045] Table 2
[0046] The performance test results of the asphalt concrete obtained in Examples 1-3 and the comparative examples are shown in Table 3. Table 3 Performance test results of asphalt concrete
[0047] This invention is not limited to the embodiments described above. Those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention. Contents not described in detail in this specification are prior art known to those skilled in the art.
Claims
1. A low-oil-to-aggregate ratio steel slag asphalt concrete, characterized in that, The components and their respective weight percentages include: 61-66 parts modified steel slag aggregate, 2-4 parts steel slag powder, 4-4.5 parts asphalt, and 30-35 parts crushed stone; wherein, the modified steel slag aggregate is obtained by coating the steel slag aggregate with a composite slurry, and the raw materials of the composite slurry include mineral powder, steel slag powder, gypsum powder, early strength agent, water repellent agent, warm wheel adhesive, and water.
2. The low asphalt-aggregate ratio steel slag asphalt concrete according to claim 1, characterized in that, The asphalt-aggregate ratio of steel slag asphalt concrete is 3.9-5%.
3. The low asphalt-aggregate ratio steel slag asphalt concrete according to claim 1, characterized in that, The modified steel slag aggregate has a particle size of 0-10 mm; the crushed stone has a particle size of 10-15 mm.
4. The low asphalt-aggregate ratio steel slag asphalt concrete according to claim 1, characterized in that, The asphalt is SBS modified asphalt, with a softening point of not less than 85℃, a ductility of more than 40cm at 5℃, and an elastic recovery rate of more than 95%.
5. The low asphalt-aggregate ratio steel slag asphalt concrete according to claim 1, characterized in that, The components and their weight percentages in the composite slurry include: 15-20 parts mineral powder, 2-6 parts steel slag powder, 3-7 parts gypsum powder, 0.1-0.3 parts early strength agent, 0.3-0.7 parts water repellent agent, 0.1-0.3 parts warm wheel adhesive, and 70-80 parts water.
6. The low asphalt-aggregate ratio steel slag asphalt concrete according to claim 1, characterized in that, The preparation method of the composite slurry includes the following steps: First, the mineral powder, steel slag powder, gypsum powder, early strength agent, water repellent agent and a portion of water are weighed according to the proportion; the warm wheel adhesive is made into powder and added to the remaining water and dispersed evenly; finally, the two mixtures are mixed to obtain the composite slurry, and the fluidity of the slurry is controlled at 160-200mm.
7. The low asphalt-aggregate ratio steel slag asphalt concrete according to claim 1, characterized in that, The mineral powder is of grade S95 or higher, with a specific surface area of 400-420 m². 2 / kg; the specific surface area of steel slag powder is 300-350m². 2 / kg; the specific surface area of the gypsum powder is not less than 300m². 2 / kg.
8. The low asphalt-aggregate ratio steel slag asphalt concrete according to claim 1, characterized in that, The early strength agent is one or more of sodium chloride, calcium chloride, and potassium chloride; the water-repellent agent is a siloxane or methylsilicate water-repellent agent.
9. The low asphalt-aggregate ratio steel slag asphalt concrete according to claim 1, characterized in that, The particle size of the steel slag aggregate is 0-10mm; the mass ratio of the composite slurry to the steel slag aggregate is 8-10:
1.
10. The method for preparing low-oil-aggregate ratio steel slag asphalt concrete according to any one of claims 1 to 9, characterized in that, Includes the following steps: 1) Weigh the raw materials according to the proportions. The raw materials and their weight percentages include: 61-66 parts of modified steel slag aggregate, 2-4 parts of steel slag powder, 4-4.5 parts of asphalt, and 30-35 parts of crushed stone. 2) First, the weighed crushed stone is mixed with the modified steel slag aggregate, then steel slag powder is added to the mixed aggregate, and finally asphalt is added and mixed. The mixture is then heated to obtain the low asphalt-aggregate ratio steel slag asphalt concrete.