阅读说明：本技术 改性钢渣及其制备方法和在sma沥青混凝土中的应用 (Modified steel slag, preparation method thereof and application thereof in SMA asphalt concrete ) 是由 张西斌 张吉哲 姜成岭 李洪印 刘贵翔 许尚江 刘伟 邢兵 余四新 徐琨 廖莹 于 2019-10-23 设计创作，主要内容包括：本发明涉及SMA沥青混凝土技术领域,尤其涉及改性钢渣及其制备方法和在SMA沥青混凝土中的应用。所述改性钢渣包括如下组分：钢渣80-90％、白泥5-10％、赤泥5-10％。本发明先将所述钢渣先进行水洗,对水洗后的钢渣烘干至完全干燥,保证得到的钢渣中游离氧化钙含量不大于2％,即得钢渣集料；然后将步骤(1)中的钢渣集料研磨,获得钢渣粗粉；将烘干后的白泥进行研磨,获得白泥粗粉；将烘干后的赤泥进行研磨,获得赤泥粗粉；将所述钢渣粗粉、白泥粗粉、赤泥粗粉按比例进行混合,然后研磨,即得改性钢渣。本发明采用钢渣、白泥、赤泥制备道路工程材料,并代替部分天然材料,解决天然石料的过度开采问题。(The invention relates to the technical field of SMA asphalt concrete, in particular to modified steel slag, a preparation method thereof and application thereof in SMA asphalt concrete. The modified steel slag comprises the following components: 80-90% of steel slag, 5-10% of white mud and 5-10% of red mud. Firstly, washing the steel slag, drying the washed steel slag until the steel slag is completely dried, and ensuring that the content of free calcium oxide in the obtained steel slag is not more than 2 percent to obtain steel slag aggregate; then grinding the steel slag aggregate in the step (1) to obtain steel slag coarse powder; grinding the dried white mud to obtain white mud coarse powder; grinding the dried red mud to obtain red mud coarse powder; and mixing the steel slag coarse powder, the white mud coarse powder and the red mud coarse powder in proportion, and then grinding to obtain the modified steel slag. The invention adopts the steel slag, the white mud and the red mud to prepare the road engineering material and replaces partial natural materials, thereby solving the problem of excessive exploitation of natural stones.)

1. The modified steel slag is characterized by comprising the following components in percentage by mass: 80-90% of steel slag, 5-10% of white mud and 5-10% of red mud.

2. The modified steel slag as claimed in claim 1, wherein the red mud is insoluble solid industrial waste discharged after alumina is extracted from bauxite processed by an alkaline method in an alumina plant; preferably, the particle size of the red mud after primary crushing is less than 10 mm.

3. The modified steel slag as claimed in claim 1, wherein the white mud is a high alkaline solid waste generated in the pulping and papermaking process, and the main component of the white mud is CaCO₃And simultaneously contains pulping fibers; preferably, the particle size of the white mud after the initial crushing is less than 10 mm.

4. The modified steel slag according to any one of claims 1 to 3, wherein said steel slag is an electric furnace steel slag tailings;

preferably, the steel slag aging time is more than 12 months, and the particle size after the initial crushing is less than 10 mm;

preferably, the steel slag is obtained by washing and drying, and the content of free calcium oxide in the finally obtained steel slag is not more than 2%.

5. The preparation method of the modified steel slag is characterized by comprising the following steps:

washing the steel slag, drying the washed steel slag until the steel slag is completely dried, and ensuring that the content of free calcium oxide in the obtained steel slag is not more than 2 percent to obtain steel slag aggregate;

grinding the steel slag aggregate in the step (1) to obtain steel slag coarse powder for later use;

grinding the dried white mud to obtain white mud coarse powder for later use;

grinding the dried red mud to obtain red mud coarse powder for later use;

the steel slag coarse powder, the white mud coarse powder and the red mud coarse powder are as follows by mass percent: 80-90% of steel slag, 5-10% of white mud and 5-10% of red mud are mixed and then ground to obtain the modified steel slag.

6. The method for preparing modified steel slag according to claim 5, wherein the drying conditions in steps (1), (3) and (4) are as follows: drying at 100-120 deg.C for 3-4.5 h;

preferably, in the steps (2) to (4), the steel slag coarse powder, the white mud coarse powder and the mud coarse powder are obtained by the following methods: grinding until the passing rate of a standard square-hole sieve with 1.18mm is 100 percent;

preferably, in the step (5), the fineness of grinding is required to be as follows: the passing rate of the standard square-hole sieve with 0.15mm is 100 percent, and the passing rate of the standard square-hole sieve with 0.075mm is 85-100 percent.

7. Use of the modified steel slag according to any one of claims 1 to 4 and/or the modified steel slag prepared by the method according to claim 5 or 6 in SMA asphalt concrete.

8. The SMA asphalt concrete is characterized by comprising the following components in percentage by mass: 4-7% of asphalt, 5-10% of modified steel slag, 50-75% of coarse aggregate, 10-36% of fine aggregate and 0.3-0.5% of fiber, wherein the modified steel slag is the modified steel slag of any one of claims 1-4 and/or the modified steel slag prepared by the method of claim 5 or 6.

9. The SMA asphalt concrete according to claim 8, wherein the asphalt is SBS modified asphalt; preferably, the coarse and fine aggregates are basalt aggregates; preferably, the fibers are lignin fibers.

10. The method for preparing SMA asphalt concrete according to claim 8 or 9, comprising the steps of:

1) respectively heating the modified steel slag powder, the coarse aggregate and the fine aggregate for later use;

2) heating SBS modified asphalt to a molten state for later use;

3) premixing coarse aggregates, fine aggregates and lignin fibers, then adding the asphalt prepared in the step (2), uniformly mixing, then adding the modified steel slag, and uniformly mixing to obtain the SMA asphalt concrete;

preferably, in step 1), the heating conditions are: heating at 160-;

preferably, in the step 2), the heating temperature is 140-160 ℃.

Technical Field

The invention relates to the technical field of SMA asphalt concrete, in particular to modified steel slag, a preparation method thereof and application thereof in SMA asphalt concrete.

Background

The information disclosed in this background of the invention is only for enhancement of understanding of the general background of the invention and is not necessarily to be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

With the development of urban construction and infrastructure construction of roads, railways and the like in China, a large amount of non-renewable resources are consumed in engineering construction. Among them, limestone in most areas of our country has become a scarce resource through several decades of destructive mining. As a main surface layer paving material for highway construction in China, namely asphalt concrete, the filler part is limestone mineral powder prepared by crushing and grinding limestone. As asphalt mastic macadam (SMA), the filler accounts for 5-10% of the total mass of the mixture, mainly plays a role in filling skeleton gaps of aggregates in the discontinuous gradation, effectively wrapping the asphalt, improving the stiffness of the asphalt, improving the adhesion of aggregate mucilage and the like, and is an indispensable important component in the SMA asphalt mixture.

With the continuous consumption of natural resources in China, particularly the enhancement of the awareness of the society on environmental protection and natural resource protection in recent years, a large number of limestone material factories are closed, so that the supply of stone materials is short of demand, and high-quality stone materials reach the extent of being snatched. Meanwhile, as a large amount of dust generated in the production process of limestone mineral powder has negative influence on the air quality, and part of unqualified limestone mineral powder production enterprises are stopped, repaired and improved, the price of the limestone mineral powder is increased year by year, and serious cost pressure is brought to highway construction investment units and construction enterprises.

The steel slag is industrial solid waste generated in the steel making process, accounts for 10 to 15 percent of the yield of crude steel, and is quite remarkable in quantity. However, at present, the comprehensive utilization of steel slag in China is limited, the utilization rate does not exceed 30%, the accumulated steel slag is over 10 hundred million tons, and thousands of tons of accumulated steel slag are increased every year. The steel slag accumulation occupies a large amount of land and pollutes the environment. With the increasing importance of society on safe production and environmental protection, the discharge and stockpiling of steel slag become important bottlenecks restricting the development of steel industry and burdens on regional social development and environmental protection. If the technology is innovated, the recycling rate of the steel slag is improved, the problem of environmental hazard caused by steel slag accumulation can be solved, the sources of building materials can be expanded, and the dilemma of natural resource shortage can be relieved. For example, in "steel slag SMA-13 asphalt concrete design and pavement performance research", li xingyu et al, by means of SMA design method, apply steel slag to road engineering, study the design and preparation of steel slag SMA-13 asphalt concrete, and perform pavement performance analysis, discuss the feasibility of steel slag as a road building material, and the study shows: the steel slag is used as a road building material for road engineering construction, so that the problem of insufficient supply of natural rocks is solved, the natural environment is protected, and the steel slag has a wide engineering application prospect. The von gem is determined by related tests in application research of steel slag fines and steel slag powder in an SMA-13 asphalt mixture to determine the application feasibility of the steel slag fines and the steel slag powder in surface layer SMA-13 asphalt concrete, researches are carried out on the grading design, the road performance and the economy of the steel slag SMA-13 mixture, and the problems of high safety risk and high cost in the application of the steel slag in the asphalt concrete at present are solved.

At present, although there are a lot of technologies for preparing and designing SMA asphalt concrete by using steel slag, the inventor finds out after research that: at present, the application of the steel slag in the asphalt concrete mainly uses the steel slag with large grain size to replace the traditional coarse aggregate, and the utilization of the steel slag micro powder is still deficient. Meanwhile, the price of limestone mineral powder is higher and higher, and the problem that how to apply the steel slag micro powder to the production of SMA asphalt concrete instead of the traditional limestone mineral powder needs to be researched.

Disclosure of Invention

The invention aims to solve the problem of developing a limestone mineral powder substitute material with controllable cost and stable performance, researching a preparation process of an asphalt mixture suitable for the substitute material, and solving the key problem to be solved in the field of road construction. Therefore, the invention provides a modified steel slag, a preparation method thereof and application thereof in SMA asphalt concrete.

The first object of the present invention: provides a modified steel slag.

The second object of the present invention: provides a preparation method of the modified steel slag.

The third object of the present invention: provides the application of the modified steel slag in SMA asphalt concrete.

In order to realize the purpose, the invention discloses the following technical scheme:

the invention discloses a modified steel slag, which comprises the following components in percentage by mass: 80-90% of steel slag, 5-10% of white mud and 5-10% of red mud.

As a further technical scheme, the steel slag is electric furnace steel slag tailings.

As a further technical scheme, the aging time of the steel slag is more than 12 months, and the grain size after the initial crushing is less than 10 mm.

As a further technical scheme, the steel slag is obtained by washing and drying, the content of free calcium oxide in the finally obtained steel slag is not more than 2%, and the washing mainly has the effects of removing or reducing the free calcium oxide and the free magnesium oxide in the steel slag and reducing the volume expansion caused by water absorption in the later period.

As a further technical scheme, the red mud is insoluble solid industrial waste discharged after alumina is extracted from bauxite processed by an alkaline method in an alumina plant, and the main component of the red mud is Al₂O₃、SiO₂、Na₂O, CaO, etc.

As a further technical scheme, the particle size of the red mud after the initial crushing is less than 10 mm.

As a further technical scheme, the white mud is high-alkalinity solid waste generated in the pulping and papermaking process, and the main component of the white mud is CaCO₃And simultaneously contains a small amount of pulping fibers.

As a further technical scheme, the grain diameter of the white mud after the initial crushing is less than 10 mm.

Secondly, the invention discloses a preparation method of the modified steel slag, which comprises the following steps:

(1) washing the steel slag, drying the washed steel slag until the steel slag is completely dried, and ensuring that the content of free calcium oxide in the obtained steel slag is not more than 2 percent to obtain steel slag aggregate;

(2) grinding the steel slag aggregate in the step (1) to obtain steel slag coarse powder for later use;

(3) grinding the dried white mud to obtain white mud coarse powder for later use;

(4) grinding the dried red mud to obtain red mud coarse powder for later use;

(5) the steel slag coarse powder, the white mud coarse powder and the red mud coarse powder are as follows by mass percent: 80-90% of steel slag, 5-10% of white mud and 5-10% of red mud are mixed and then ground to obtain the modified steel slag.

As a further method, in the steps (1), (3) and (4), the drying conditions are all as follows: drying at 100-120 deg.C for 3-4.5 h.

As further methods, in the steps (2) to (4), the steel slag coarse powder, the white mud coarse powder and the mud coarse powder are obtained by the following methods: grinding until the passing rate of a standard square-hole sieve with 1.18mm is 100 percent.

As a further method, in the step (5), the fineness of grinding is required to be: the passing rate of the standard square-hole sieve with 0.15mm is 100 percent, and the passing rate of the standard square-hole sieve with 0.075mm is 85-100 percent.

The invention further discloses an application of the modified steel slag in the SMA asphalt concrete, and specifically relates to the SMA asphalt concrete, which comprises the following components in percentage by mass: 4-7% of asphalt, 5-10% of modified steel slag, 50-75% of coarse aggregate, 10-36% of fine aggregate and 0.3-0.5% of fiber.

As a further method, the asphalt is SBS modified asphalt.

As a further method, the coarse and fine aggregates are basalt aggregates.

As a further method, the fiber is a lignin fiber.

Finally, the invention discloses a preparation method of the SMA asphalt concrete, which comprises the following steps:

1) respectively heating the modified steel slag powder, the coarse aggregate and the fine aggregate for later use;

2) heating SBS modified asphalt to a molten state for later use;

3) premixing coarse aggregate, fine aggregate and lignin fiber, adding the asphalt prepared in the step (2), uniformly mixing, adding the modified steel slag, and uniformly mixing to obtain the SMA asphalt concrete.

As a further technical scheme, in the step 1), the heating conditions are as follows: heating at 160-180 ℃ for 4 h.

As a further technical scheme, in the step 2), the heating temperature is 140-160 ℃.

The technical principle of the invention is as follows: the steel slag belongs to a high-alkalinity porous material, has better adhesiveness with weakly acidic asphalt, and can effectively wrap the asphalt in the SMA asphalt concrete to form an asphalt horseshoe grease structure. In order to eliminate the negative effect of free calcium oxide in asphalt concrete system, the content of free calcium oxide is effectively reduced by adopting a water washing method. In the ball milling process, calcium carbonate in the white mud can fill a part of micro-gaps of the steel slag, so that the leaching of free calcium oxide is effectively inhibited, and a small amount of lignin fiber in the white mud can also improve the coating capability with asphalt. Meanwhile, the red mud serving as a porous material can be fully filled and locked with the steel slag micro powder in the ball milling process, so that the adhesion between the modified steel slag powder and the asphalt is improved, and the coating capacity of the asphalt is improved. Through the modification, the invention successfully converts the common steel slag into a product suitable for replacing limestone, so that the steel slag can be used for preparing the SMA asphalt concrete.

Compared with the prior art, the invention has the following beneficial effects:

(1) the invention adopts three solid wastes, namely steel slag, white mud and red mud, to prepare the road engineering material and replaces partial natural materials, thereby not only solving the problem of excessive exploitation of natural stones and protecting natural resources, but also absorbing the solid wastes and reducing environmental pollution, and having remarkable environmental and social benefits.

(2) The modified steel slag powder prepared by using the steel slag as the main raw material has good adhesion with asphalt, can effectively ensure the water damage resistance of the asphalt horseshoe resin, and prolongs the service life of the SMA asphalt concrete.

(3) The invention adopts three solid waste materials to prepare the modified steel slag powder, has wide raw material sources, low price, simple preparation process and convenient operation, can effectively reduce the production cost of the SMA asphalt concrete and has wide application prospect.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms also are intended to include the plural forms as well, unless the context clearly indicates otherwise, and it should be further understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, devices, components, and/or combinations thereof.

As described above, the development of limestone mineral powder substitute materials with controllable cost and stable performance is an important key problem to be solved in the field of road construction in order to research the preparation process of asphalt mixtures suitable for the substitute materials. Therefore, the invention provides a modified steel slag, a preparation method thereof and application thereof in SMA asphalt concrete, and the invention is further explained by combining with a specific embodiment.

In the following examples, the steel slag is obtained from Minyuan Steel Co., Ltd, and the steel slag is an electric furnace steel slag tailings, the aging time is more than 12 months, and the particle size after the initial crushing is less than 10 mm.

In the following examples, the red mud is obtained from Shandong aluminum group, and the red mud is insoluble solid industrial waste discharged after alumina is extracted from bauxite treated by alkaline process, and the main component is Al₂O₃、SiO₂、Na₂O, CaO, etc.

In the following examples, it is preferred that,the white mud is purchased from the Qihe paper mill, is high-alkalinity solid waste generated in the pulping and papermaking process, and mainly comprises CaCO₃And simultaneously contains a small amount of pulping fibers.