Concrete using high-plasticity index asphalt mixing station recycled powder and preparation method thereof

Abstract

The invention belongs to the technical field of concrete materials, and relates to concrete using high plasticity index asphalt mixing station recovered powder and a preparation method thereof, the concrete comprises the following components by weight: 9-21 parts of a cementing material, 47-53 parts of a coarse aggregate, 25-30 parts of a fine aggregate, 0.5-1.5 parts of a composite silicon enhancer, 0.3-0.7 part of a slump retaining polycarboxylic acid water reducer, and 5-8 parts of water. The mixing ratio of the recycled powder of the asphalt station accounts for 30-60% of the total cementing material, the water-binder ratio is 0.36-0.45, the compressive strength grade of the concrete can reach C30-C45, and the concrete can be used in the engineering fields of municipal administration, roads, civil engineering and the like as commercially available concrete with the same strength grade; according to the method, recycling of the recycled powder of the asphalt mixing station is achieved, and the method has good economical efficiency and environmental protection performance and is of great significance to cost reduction, efficiency improvement and sustainable development of enterprises.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete materials, and relates to concrete using recycled powder from an asphalt mixing station with a high plasticity index and a preparation method thereof. Background Art

[0002] When an asphalt mixing plant produces asphalt mixture, a large amount of dust is generated. The commonly used treatment methods for the generated dust are wet treatment or dry treatment. Wet treatment consumes a lot of water. At the same time, after sedimentation, the sewage needs to be treated to meet the discharge index before it can be discharged; dry treatment is the method adopted by most mixing plants, that is, the method of using bags to recover dust. The dust recovered in this way is called recycled powder. Most of the recycled powder comes from the powder below 0.075mm in the aggregate below 3mm. In order to reduce costs, the powder content of stones below 3mm in actual applications is generally about 10%. Therefore, the recycled waste powder with a particle size of less than 0.075mm is relatively large. According to statistics, an asphalt mixing plant will produce 8 to 10 tons of recycled powder for every 100t of asphalt concrete produced. The recycled powder produced each year is as high as tens of millions of tons, resulting in the recycling of powder occupying a large area of ​​land.

[0003] In order to reduce the harm to the environment and advocate the use of green building materials, on the one hand, it is necessary to reduce the production of cement, which is "three highs" with high energy consumption, high pollution and high emissions, and use other materials to replace cement or partially replace cement in engineering. On the other hand, recycled powder should be used in engineering to reduce the land resources occupied by its stacking.

[0004] The lithology of the recycled powder produced in the asphalt mixture production process is basically consistent with the corresponding ground material. The most widely used areas for recycled powder from asphalt plants are asphalt mixtures and asphalt mortars, but its plasticity index must not be greater than 4%. However, in actual projects, the soil content of recycled powder from asphalt plants is relatively high, and its application in asphalt mixtures is limited. There are even fewer studies on its application in concrete. At present, the maximum amount of recycled powder from asphalt plants in cementitious materials for medium-strength concrete is less than 15%. If the recycled powder is not well utilized and is dumped and disposed of, it will not only cause a waste of resources, but may also cause dust pollution. In view of this, it is necessary to develop a concrete and a preparation method thereof that can realize the application of large amounts of recycled powder in concrete. Summary of the invention

[0005] In view of the shortcomings of the above-mentioned prior art, the present invention provides a concrete using recycled powder from a high plasticity index asphalt mixing plant and a preparation method thereof, and realizes the large-volume application of recycled powder in concrete by adopting new additives, mix ratio design, process adjustment, etc. The specific technical scheme is as follows:

[0006] The first object of the present invention is to provide a concrete using recycled powder from an asphalt mixing plant with a high plasticity index, comprising the following components in parts by weight:

[0007] 9-21 parts of cementitious materials, 47-53 parts of coarse aggregate, 25-30 parts of fine aggregate, 0.5-1.5 parts of composite silicon reinforcing agent, 0.3-0.7 parts of collapse-preserving polycarboxylic acid water-reducing agent and 5-8 parts of water;

[0008] The cementitious material is 3 to 7 parts of P·O42.5 grade cement, 2 to 6 parts of blast furnace slag powder, and 4 to 8 parts of asphalt station recycled powder;

[0009] The particle size of the coarse aggregate is 5 to 25 mm; the particle size of the fine aggregate is less than 5 mm, and the plasticity index is 4% to 15%.

[0010] In the concrete using high plasticity index recycled powder from asphalt mixing stations prepared by the present invention, the recycled powder from asphalt mixing stations accounts for 30% to 60% of the total cementitious materials. The recycled powder from asphalt mixing stations is added in a relatively large proportion. Firstly, the particle size of the recycled powder belongs to an inert material and is a particle of less than 100 microns. Through the filling effect, the internal pores of the concrete can be improved, the number of pores can be reduced, and the interior of the concrete can be made denser. Secondly, the recycled powder can be filled in the pore structure of the cement matrix and the interface between the coarse aggregate and the newly hardened cement paste, thereby improving the density of the cement matrix and the interface transition zone. Thirdly, there is a nucleation phenomenon around the cement paste filled in the pore structure, and hydration products are gradually formed and settled on the surface of the cement paste, thereby accelerating the hydration of the cement. After reasonable proportioning, the recycled powder from asphalt mixing stations not only has the function of filling pores and making the interface dense, but also has the function of promoting the hydration of the cement. The addition of blast furnace slag powder can replace part of the cement and fill the smaller gaps between P·O42.5 grade cement, thereby improving the working performance of the concrete mixture, meeting the mechanical properties of the concrete after molding, and reducing the cost of cementitious materials.

[0011] Since the present invention incorporates a relatively large proportion of recycled powder from asphalt stations and has a relatively large plasticity index (4% to 15%), that is, the content of soil components is relatively high, the addition of a composite silicon strengthening agent reduces the adverse effects of soil components on concrete properties, including workability, mechanical properties, and durability. This is because when the aggregate contains a large amount of mud, the mud will not only occupy part of the pores in the concrete, reducing the density of the concrete, but will also compete with the active ingredients in the admixture for adsorption, resulting in a reduction in the effective ingredients of the admixture, reduced fluidity, and increased construction difficulty, thereby reducing the compressive strength and durability of the concrete.

[0012] The slump-retaining polycarboxylate water-reducing agent incorporated in the present invention is a high-performance water-reducing agent containing macromolecular compounds such as sulfonic acid groups, carboxylic acid groups, amino groups and polyoxyethylene side chains, which can greatly improve the problem of reduced concrete performance caused by high mud content. When the slump-retaining polycarboxylate water-reducing agent is added to cement concrete, especially in concrete with a large aggregate mud content, its anionic main chain will be adsorbed on the surface of cement particles and their hydration products, while the side chain will be inserted into the liquid phase. In this way, an adsorption layer with side chains and side chains will be formed on the surface of cement particles. When cement particles are close to each other and the adsorption layers overlap, steric repulsion will be generated between the side chains and side chains of the polycarboxylate water-reducing agent on the surface of cement particles, so that the water between cement particles becomes free water, thereby promoting the improvement and improvement of the fluidity of cement concrete.

[0013] Furthermore, the concrete using recycled powder from a high plasticity index asphalt mixing plant comprises the following components in parts by weight:

[0014] 15 parts of cementitious materials, 50 parts of coarse aggregate, 27 parts of fine aggregate, 1 part of composite silicon reinforcing agent, 0.5 parts of collapse-preserving polycarboxylate water-reducing agent and 6.5 parts of water;

[0015] The cementitious material is 5 parts of P·O42.5 grade cement, 4 parts of blast furnace slag powder, and 6 parts of asphalt station recycled powder.

[0016] Furthermore, the blast furnace slag powder is S95 grade ore powder with a specific surface area of ​​450-480m 2 / kg.

[0017] Furthermore, the asphalt station recycled powder is one or more of limestone, basalt, and granite aggregates, and the fineness of the asphalt station recycled powder is ≤10% (such as obtained by 45μm negative pressure screening method), and the apparent density is 2.5kg / m 3 ~2.7kg / m 3 .

[0018] Furthermore, the coarse aggregate is a composite aggregate of one or both of natural aggregate and recycled aggregate, and the gradation of the coarse aggregate is a continuous gradation of 5 to 25 mm.

[0019] Furthermore, the fine aggregate is one or more of river sand, mountain sand, machine-made sand or tailings sand, and the fineness modulus of the fine aggregate is 2.3 to 3.0.

[0020] Furthermore, the composite silicon reinforcing agent comprises the following components in parts by weight: 20 to 30 parts of silica sol, 10 to 20 parts of KH550 coupling agent, and 50 to 60 parts of soil plugging agent;

[0021] The soil plugging agent is pentaerythritol maleate, which is polymerized from maleic anhydride and tetrafluoroethylene.

[0022] The composite silicon strengthening agent of the present invention is formed by mixing and modifying silica sol, silane coupling agent and soil plugging agent. The soil plugging agent pentaerythritol maleate in the composite silicon strengthening agent of the present invention utilizes the particle coating principle to chemically branch the non-sticky polyfluoroethylene (Teflon), that is, to appropriately perform carboxylation in the tetrafluoroethylene molecule, and the polymer obtained by polymerizing the modified tetrafluoroethylene monomer has a strong polarity, so that the system containing such a small amount of substance has a strong adsorption and coating property, thereby coating some soil particles in the porous and high water absorption asphalt station recycled powder and isolating them from water, thereby making the concrete fluid.

[0023] The silica sol added to the composite silicon strengthening agent of the present invention has a certain refining effect. It reacts with calcium hydroxide, a cement hydration product in concrete, to form silicate, which can reduce the porosity in the concrete, reduce shrinkage cracks caused by high soil content in the recycled powder, make the concrete dense, and further improve its durability and impermeability. In addition, the silica sol can also promote the hydration reaction of cement. Silicon dioxide reacts with calcium hydroxide after cement hydration to form calcium silicate sol, which accelerates the coagulation and hardening process of concrete and improves the early strength of concrete.

[0024] The amino functional group provided by the KH550 silane coupling agent in the composite silicon strengthening agent of the present invention improves the interfacial bonding force between materials, can be well combined with solid waste cementitious materials, improve the dispersibility of materials, and thus improve the fluidity of concrete; in addition, the addition of silane coupling agents can form molecular bridges between the polymer soil plugging agent pentaerythritol maleate and inorganic substrates (cement, fine aggregate, etc.), increase the bonding strength, and improve the interfacial bonding between concrete materials. It can be seen that the addition of the composite silicon strengthening agent in the present invention has multiple strengthening effects on water absorption, interfacial bonding, and enhanced fluidity of the plugging soil particles.

[0025] Furthermore, the preparation method of the soil plugging agent is to dissolve maleic anhydride and tetrafluoroethylene in anhydrous ethanol, add an initiator, and polymerize for 3 to 5 hours under the conditions of temperature 85±5°C and pressure 1 to 3MPa to synthesize the soil plugging agent pentaerythritol maleate, wherein the mass ratio of maleic anhydride to tetrafluoroethylene is 1:850 to 900; the mass of the anhydrous ethanol is 4 to 6 times the sum of the mass of the maleic anhydride and tetrafluoroethylene; the mass of the initiator is 0.05 to 0.2% of the sum of the mass of the maleic anhydride and tetrafluoroethylene.

[0026] Furthermore, the initiator is sodium peroxide.

[0027] Furthermore, the preparation method of the composite silicon reinforcing agent is to cool the soil plugging agent, continuously stir the silica sol and the KH550 coupling agent for at least 5 minutes, and maintain the temperature at 50°C±5°C; then cool the obtained reaction solution to room temperature to obtain the composite silicon reinforcing agent.

[0028] Furthermore, the collapse-preserving polycarboxylate water-reducing agent is a polycarboxylate water-reducing agent with model D0001 and a water-reducing rate of ≥25% produced by Shanxi Bajunma Building Materials Co., Ltd.

[0029] The second object of the present invention is to provide a method for preparing the above-mentioned concrete using recycled powder from an asphalt mixing plant with a high plasticity index and a method for preparing the same, comprising the following steps:

[0030] S1: dissolving the composite silicon strengthening agent in water to obtain a composite silicon strengthening agent solution;

[0031] S2: Mix P·O42.5 grade cement, blast furnace slag powder, asphalt station recycled powder and fine aggregate evenly, then pour in the composite silicon strengthening agent solution and continue stirring for at least 2 minutes to obtain a mixture;

[0032] S3: Add coarse aggregate and collapse-retaining polycarboxylate water-reducing agent into the mixture and continue stirring for 2 to 4 minutes to obtain concrete using recycled powder from a high plasticity index asphalt mixing station.

[0033] In the process of preparing concrete using high plasticity index asphalt mixing station recycled powder, the present invention adopts a concrete forced mixing process of classified step-by-step addition and two-time mixing according to the characteristics of the materials, that is, the composite silicon strengthening agent is first dissolved in water, and then P·O42.5 grade cement, blast furnace slag powder, asphalt station recycled powder, and fine aggregate are poured into forced mixing, and the composite silicon strengthening agent is added after dry mixing, and stirred into a mortar mixture; finally, coarse aggregate and collapse-preserving polycarboxylic acid water reducer are added and continued to be stirred. Through the adjustment of the above mixing process, not only the competitive adsorption between the mud and the active ingredients in the water reducer is weakened, resulting in a reduction in the effective ingredients of the admixture and affecting the water reduction effect, but also the mixing time is appropriately extended, and through the early blocking of the asphalt station recycled powder, uniform dispersion, effective use of the water reducer, and sufficient mixing, the goal of achieving a concrete compressive strength grade of C30 to C45 is achieved with relatively less active cementitious materials.

[0034] The beneficial effects of the present invention are:

[0035] The concrete prepared by the present invention using the recycled powder from the asphalt mixing station with a high plasticity index reduces the porosity, improves the fluidity durability and impermeability of the concrete, etc., the mixing ratio of the recycled powder from the asphalt mixing station accounts for 30% to 60% of the total cementitious materials, the water-cement ratio is between 0.36 and 0.45, and the compressive strength grade thereof can reach C30 to C45, and can be used in engineering fields such as municipal engineering, highways, and civil engineering just like the commercially available concrete with the same strength grade; the present invention realizes the recycling of the recycled powder from the asphalt mixing station, reduces the demand for fresh raw materials, saves resources, reduces costs, and reduces environmental pollution; and has good economy and environmental protection, and is of great significance to the cost reduction, efficiency improvement, and sustainable development of enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a photograph of a C40 concrete specimen prepared in Example 1 of the present invention using recycled powder from an asphalt mixing plant with a high plasticity index. DETAILED DESCRIPTION

[0037] The principles and features of the present invention are described below in conjunction with examples. The examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0038] The blast furnace slag powder is S95 grade ore powder produced by Laiwu Rongbang Economic and Trade Co., Ltd., with a specific surface area of ​​450-480m 2 / kg;

[0039] Asphalt station recycled powder is the recycled powder from limestone aggregate heating, which is obtained by 45μm negative pressure screening method, with a fineness of ≤10% and an apparent density of 2.5kg / m 3 ~2.7kg / m 3 , plasticity index is 10%;

[0040] The coarse aggregate is limestone crushed stone coarse aggregate produced by the stone material factory in Dong'e Town, Pingyin County, with a continuous gradation of 5 to 25 mm;

[0041] The fine aggregate is limestone machine-made sand produced by the stone material factory in Dong'e Town, Pingyin County, and the fineness modulus of the fine aggregate machine-made sand is 2.3-3.0, and the particle size is 2-5 mm;

[0042] The collapse-preserving polycarboxylic acid water-reducing agent is produced by Shanxi Bajunma Building Materials Co., Ltd., with model number D0001 and a water-reducing rate of ≥25%.

[0043] The above materials were used in the following examples and comparative examples.

[0044] Embodiment 1:

[0045] A concrete using recycled powder from an asphalt mixing plant with a high plasticity index, comprising the following components in parts by weight:

[0046] 5 parts of P·O42.5 grade cement, 4 parts of blast furnace slag powder, 6 parts of recycled powder from asphalt station, 50 parts of coarse aggregate, 27 parts of fine aggregate, 1 part of composite silicon strengthener, 0.5 parts of collapse-preserving polycarboxylate water reducer and 6.5 parts of water.

[0047] The preparation method of the composite silicon strengthening agent comprises the following steps:

[0048] A1: Dissolve maleic anhydride and tetrafluoroethylene in anhydrous ethanol at a mass ratio of 1:850, use sodium peroxide as an initiator, and polymerize for 4 hours at a temperature of 85°C and a pressure of 2MPa to synthesize a soil plugging agent, pentaerythritol maleate; the mass of the anhydrous ethanol is 5 times the mass of the maleic anhydride and tetrafluoroethylene; the mass of the initiator is 0.1% of the mass of the maleic anhydride and tetrafluoroethylene;

[0049] A2: Cool the synthetic soil plugging agent pentaerythritol maleate prepared in step A1 to 50°C, add 60 parts of pentaerythritol maleate, 25 parts of silica sol and 15 parts of KH550 coupling agent by mass into a magnetic stirrer, maintain the temperature between 50°C±5°C, and stir continuously for 5 minutes; then cool the obtained solution to room temperature to obtain a light yellow solution composite silicon strengthener.

[0050] The method for preparing concrete using recycled powder from an asphalt mixing station with a high plasticity index comprises the following steps:

[0051] S1: dissolving the composite silicon strengthening agent in water to obtain a composite silicon strengthening agent solution;

[0052] S2: P·O42.5 grade cement, blast furnace slag powder, asphalt station recycled powder and fine aggregate are poured into a forced mixer for dry mixing for 35 seconds, and then the composite silicon strengthening agent solution is poured in and stirred for 2 minutes to obtain a mixture;

[0053] S3: Add coarse aggregate and collapse-retaining polycarboxylate water-reducing agent into the mixture and continue stirring for 2 minutes to obtain concrete using recycled powder from a high plasticity index asphalt mixing plant.

[0054] Preparation of concrete test blocks: After the slump of the concrete prepared in Example 1 using the recycled powder of the high plasticity index asphalt mixing plant meets the design requirements, it is loaded into a 150mm×150mm×150mm medium, at least 6 pieces, and compacted on a concrete compaction table for at least 20s. At the same time, at least 2 groups of flexural test pieces are prepared. After standing for 6 hours, they can be placed in a standard curing room for standard curing. The obtained C40 concrete test blocks are as follows: Figure 1 shown.

[0055] After testing, it was found that when the recycled powder from the asphalt station accounted for 40% of the total cementitious materials and the water-cement ratio was 0.43, its R28 compressive strength was 42.2MPa, the flexural strength was 5.3MPa, and the number of rapid freeze-thaw tests reached 220 times, which met the C30 strength grade requirements in the "Code for Design of Ordinary Concrete Mix" (JGJ55-2011).

[0056] Embodiment 2:

[0057] A concrete using recycled powder from an asphalt mixing plant with a high plasticity index, comprising the following components in parts by weight:

[0058] 6 parts of P·O42.5 grade cement, 4 parts of blast furnace slag powder, 5 parts of recycled powder from asphalt station, 50 parts of coarse aggregate, 27 parts of fine aggregate, 1.5 parts of composite silicon strengthener, 0.5 parts of collapse-preserving polycarboxylate water reducer and 6 parts of water.

[0059] The preparation method of the composite silicon strengthening agent comprises the following steps:

[0060] A1: Dissolve maleic anhydride and tetrafluoroethylene in anhydrous ethanol at a mass ratio of 1:850, use sodium peroxide as an initiator, and polymerize for 4 hours at a temperature of 85°C and a pressure of 2MPa to synthesize a soil plugging agent, pentaerythritol maleate; the mass of the anhydrous ethanol is 5 times the mass of the maleic anhydride and tetrafluoroethylene; the mass of the initiator is 0.1% of the mass of the maleic anhydride and tetrafluoroethylene;

[0061] A2: Cool the synthetic soil plugging agent pentaerythritol maleate prepared in step A1 to 50°C, add 62 parts of pentaerythritol maleate, 23 parts of silica sol and 15 parts of KH550 coupling agent by mass into a magnetic stirrer, maintain the temperature between 50°C±5°C, and stir continuously for 5 minutes; then cool the obtained solution to room temperature to obtain a light yellow solution composite silicon strengthener.

[0062] The preparation of the concrete using the recycled powder from the high plasticity index asphalt mixing plant and the preparation of the concrete test blocks are the same as those in Example 1, and will not be described again here.

[0063] After testing, it was found that when the recycled powder from the asphalt station accounted for 33.3% of the total cementitious materials and the water-cement ratio was 0.4, its R28 compressive strength was 48.6MPa, the flexural strength was 5.6MPa, and the number of rapid freeze-thaw tests reached 235 times, which met the C40 strength grade requirements in the "Code for Design of Ordinary Concrete Mix" (JGJ55-2011).

[0064] Embodiment 3:

[0065] A concrete using recycled powder from an asphalt mixing plant with a high plasticity index, comprising the following components in parts by weight:

[0066] 7 parts of P·O42.5 grade cement, 4 parts of blast furnace slag powder, 5 parts of recycled powder from asphalt station, 50 parts of coarse aggregate, 26.7 parts of fine aggregate, 1 part of composite silicon strengthener, 0.5 parts of collapse-preserving polycarboxylate water reducer and 5.8 parts of water.

[0067] The composite silicon strengthening agent comprises the following steps:

[0068] A1: Dissolve maleic anhydride and tetrafluoroethylene in anhydrous ethanol at a mass ratio of 1:850, use sodium peroxide as an initiator, and polymerize for 4 hours at a temperature of 85°C and a pressure of 2MPa to synthesize a soil plugging agent, pentaerythritol maleate; the mass of the anhydrous ethanol is 5 times the mass of the maleic anhydride and tetrafluoroethylene; the mass of the initiator is 0.1% of the mass of the maleic anhydride and tetrafluoroethylene;

[0069] A2: Cool the synthetic soil plugging agent pentaerythritol maleate prepared in step A1 to 50°C, add 55 parts of pentaerythritol maleate, 27 parts of silica sol and 18 parts of KH550 coupling agent by mass into a magnetic stirrer, maintain the temperature between 50°C±5°C, and stir continuously for 5 minutes; then cool the obtained solution to room temperature to obtain a light yellow solution composite silicon strengthener.

[0070] The preparation of the concrete using the recycled powder from the high plasticity index asphalt mixing plant and the preparation of the concrete test blocks are the same as those in Example 1, and will not be described again here.

[0071] After testing, it was found that when the recycled powder from the asphalt station accounted for 31.3% of the total cementitious materials and the water-cement ratio was 0.36, its R28 compressive strength was 53.9MPa, the flexural strength was 5.7MPa, and the number of rapid freeze-thaw tests reached 275 times, which met the C45 strength grade requirements in the "Code for Design of Ordinary Concrete Mix" (JGJ55-2011).

[0072] Embodiment 4:

[0073] A concrete using recycled powder from an asphalt mixing plant with a high plasticity index, comprising the following components in parts by weight:

[0074] 7 parts of P·O42.5 grade cement, 4 parts of blast furnace slag powder, 8 parts of recycled powder from asphalt station, 47 parts of coarse aggregate, 25.5 parts of fine aggregate, 1.5 parts of composite silicon strengthener, 0.5 parts of collapse-preserving polycarboxylate water reducer and 6.5 parts of water.

[0075] The composite silicon strengthening agent comprises the following steps:

[0076] A1: Dissolve maleic anhydride and tetrafluoroethylene in anhydrous ethanol at a mass ratio of 1:850, use sodium peroxide as an initiator, and polymerize for 4 hours at a temperature of 85°C and a pressure of 2MPa to synthesize a soil plugging agent, pentaerythritol maleate; the mass of the anhydrous ethanol is 5 times the mass of the maleic anhydride and tetrafluoroethylene; the mass of the initiator is 0.1% of the mass of the maleic anhydride and tetrafluoroethylene;

[0077] A2: Cool the synthetic soil plugging agent pentaerythritol maleate prepared in step A1 to 50°C, add 52 parts of pentaerythritol maleate, 28 parts of silica sol and 20 parts of KH550 coupling agent by mass into a magnetic stirrer, maintain the temperature between 50°C±5°C, and stir continuously for 5 minutes; then cool the obtained solution to room temperature to obtain a light yellow solution composite silicon strengthener.

[0078] The preparation of the concrete using the recycled powder from the high plasticity index asphalt mixing plant and the preparation of the concrete test blocks are the same as those in Example 1, and will not be described again here.

[0079] After testing, it was found that when the recycled powder from the asphalt station accounted for 42.1% of the total cementitious materials and the water-cement ratio was 0.36, its R28 compressive strength was 55.1MPa, the flexural strength was 5.8MPa, and the number of rapid freeze-thaw tests reached 266 times, which met the C45 strength grade requirements in the "Code for Design of Ordinary Concrete Mix" (JGJ55-2011).

[0080] Embodiment 5:

[0081] A concrete using recycled powder from an asphalt mixing plant with a high plasticity index, comprising the following components in parts by weight:

[0082] 5 parts of P·O42.5 grade cement, 4 parts of blast furnace slag powder, 8 parts of recycled powder from asphalt station, 48 parts of coarse aggregate, 26.5 parts of fine aggregate, 1.5 parts of composite silicon strengthener, 0.5 parts of collapse-preserving polycarboxylate water reducer and 6.5 parts of water.

[0083] The preparation of the composite silicon strengthening agent, the preparation of the concrete using the recycled powder from the high plasticity index asphalt mixing plant, and the preparation of the concrete test block are the same as those in Example 1 and will not be described in detail here.

[0084] After testing, it was found that when the recycled powder from the asphalt station accounted for 47.0% of the total cementitious materials and the water-cement ratio was 0.38, its R28 compressive strength was 45.5MPa, the flexural strength was 5.1MPa, and the number of rapid freeze-thaw tests reached 231 times, which met the C35 strength grade requirements in the "Code for Design of Ordinary Concrete Mix" (JGJ55-2011).

[0085] Comparative Example 1:

[0086] A concrete made of recycled powder from an asphalt mixing plant, comprising the following components in parts by weight:

[0087] 5 parts of P·O42.5 grade cement, 4 parts of blast furnace slag powder, 9 parts of recycled powder from asphalt station, 48 parts of coarse aggregate, 25 parts of fine aggregate, 1 part of composite silicon strengthener, 0.5 parts of collapse-preserving polycarboxylate water reducer and 7.5 parts of water.

[0088] The preparation of the composite silicon strengthening agent, the preparation of the concrete using the recycled powder from the high plasticity index asphalt mixing plant, and the preparation of the concrete test block are the same as those in Example 1 and will not be described in detail here.

[0089] In this comparative example, the recycled powder from the asphalt plant is increased to 9 parts. Under the condition of ensuring workability, the coarse aggregate is reduced by 2 parts, the fine aggregate is reduced by 2 parts, and the water is increased by 1 part. After 28 days of curing, the recycled powder from the asphalt plant accounts for 50.0% of the total cementitious material. When the water-cement ratio is 0.42, the R28 compressive strength is 31.5 MPa and the flexural tensile strength is 4.1 MPa. Compared with Example 1, it no longer meets the C30 strength grade requirement in the "Code for Design of Ordinary Concrete Mix" (JGJ55-2011).

[0090] Comparative Example 2:

[0091] A concrete made of recycled powder from an asphalt mixing plant, comprising the following components in parts by weight:

[0092] 4 parts of P·O42.5 grade cement, 2 parts of blast furnace slag powder, 9 parts of recycled powder from asphalt station, 50 parts of coarse aggregate, 27 parts of fine aggregate, 1 part of composite silicon strengthener, 0.5 parts of collapse-preserving polycarboxylate water reducer and 6.5 parts of water.

[0093] The preparation of the composite silicon strengthening agent, the preparation of the concrete using the recycled powder from the high plasticity index asphalt mixing plant, and the preparation of the concrete test block are the same as those in Example 1 and will not be described in detail here.

[0094] In this comparative example, the amount of P·O42.5 grade cement is reduced to 4 parts, the amount of blast furnace slag powder is reduced to 2 parts, and the amount of recycled powder from the asphalt plant is increased to 9 parts. When the total amount of cementitious materials and other materials remains unchanged, compared with Example 1, during mixing, the concrete partially shows a clumping phenomenon, and the slump is only 50 mm, which does not meet the workability requirements of on-site construction (slump of 140 mm to 180 mm). This is because too much recycled powder from the asphalt plant is added, and its blending ratio reaches 60% of the total cementitious materials. The content of soil particles in the recycled powder is relatively increased, and more water and water reducer are absorbed, resulting in a decrease in overall workability.

[0095] Comparative Example 3:

[0096] A concrete made of recycled powder from an asphalt mixing plant, comprising the following components in parts by weight:

[0097] 8 parts of P·O42.5 grade cement, 4 parts of blast furnace slag powder, 3 parts of recycled powder from asphalt station, 50 parts of coarse aggregate, 27 parts of fine aggregate, 0.5 parts of slump-retaining polycarboxylate water reducer and 6.5 parts of water.

[0098] The preparation of the composite silicon strengthening agent, the preparation of the concrete using the recycled powder from the high plasticity index asphalt mixing plant, and the preparation of the concrete test block are the same as those in Example 1 and will not be described in detail here.

[0099] In this comparative example, the P·O42.5 grade cement is increased to 8 parts, the recycled powder from the asphalt station is reduced to 3 parts, and the composite silicon strengthening agent is reduced to 0 parts. When the total cementitious materials and other materials remain unchanged, compared with Example 1, the recycled powder from the asphalt station accounts for 20.0% of the total cementitious materials, and the water-cement ratio is 0.43. The compressive strength of the R28 specimen is 39.9 MPa and the flexural tensile strength is 4.2 MPa. Although it meets the C30 strength grade requirements in the "Ordinary Concrete Mix Design Code" (JGJ55-2011), the "three highs" cement content is increased, which no longer meets the goal of a large content of the present invention.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A concrete using recycled powder from a high plasticity index asphalt mixing plant, characterized in that: The composition comprises the following components in parts by weight: 9-21 parts of cementitious materials, 47-53 parts of coarse aggregate, 25-30 parts of fine aggregate, 0.5-1.5 parts of composite silicon reinforcing agent, 0.3-0.7 parts of collapse-preserving polycarboxylic acid water-reducing agent and 5-8 parts of water; The cementitious material is 3 to 7 parts of P·O42.5 grade cement, 2 to 6 parts of blast furnace slag powder, and 4 to 8 parts of asphalt station recycled powder; The particle size of the coarse aggregate is 5 to 25 mm; the particle size of the fine aggregate is less than 5 mm, and the plasticity index is 4% to 15%.

2. The concrete using recycled powder from high plasticity index asphalt mixing plant according to claim 1, characterized in that: The composition comprises the following components in parts by weight: 15 parts of cementitious materials, 50 parts of coarse aggregate, 27 parts of fine aggregate, 1 part of composite silicon strengthening agent, 0.5 parts of collapse-preserving polycarboxylate water-reducing agent and 6.5 parts of water; The cementitious material is 5 parts of P·O42.5 grade cement, 4 parts of blast furnace slag powder, and 6 parts of asphalt station recycled powder.

3. The concrete using recycled powder from high plasticity index asphalt mixing plant according to claim 1, characterized in that: The blast furnace slag powder is S95 grade ore powder with a specific surface area of ​​450-480m 2 / kg; the recycled powder of the asphalt station is one or more of limestone, basalt, and granite aggregates; the fineness of the recycled powder of the asphalt station is ≤10% and the apparent density is 2.5kg / m 3 ~2.7kg / m 3 .

4. The concrete using recycled powder from a high plasticity index asphalt mixing plant according to claim 2, characterized in that: The coarse aggregate is a composite aggregate of one or both of natural aggregate and recycled aggregate, and the gradation of the coarse aggregate is a continuous gradation of 5 to 25 mm.

5. The concrete using recycled powder from high plasticity index asphalt mixing plant according to claim 4, characterized in that: The fine aggregate is one or more of river sand, mountain sand, machine-made sand or tailings sand, and the fineness modulus of the fine aggregate is 2.3 to 3.

0.

6. The concrete using recycled powder from high plasticity index asphalt mixing plant according to claim 1, characterized in that: The composite silicon reinforcing agent comprises the following components in parts by weight: 20 to 30 parts of silica sol, 10 to 20 parts of KH550 coupling agent, and 50 to 60 parts of soil plugging agent; The soil plugging agent is pentaerythritol maleate, which is polymerized from maleic anhydride and tetrafluoroethylene.

7. The concrete using recycled powder from high plasticity index asphalt mixing plant according to claim 6, characterized in that: The preparation method of the soil plugging agent is as follows: dissolving maleic anhydride and tetrafluoroethylene in anhydrous ethanol, adding an initiator, polymerizing for 3 to 5 hours at a temperature of 85±5°C and a pressure of 1 to 3MPa to synthesize pentaerythritol maleate as a soil plugging agent, wherein the mass ratio of the maleic anhydride to the tetrafluoroethylene is 1:850 to 900; the mass of the anhydrous ethanol is 4 to 6 times the mass sum of the maleic anhydride and the tetrafluoroethylene; and the mass of the initiator is 0.05 to 0.2% of the mass sum of the maleic anhydride and the tetrafluoroethylene.

8. The concrete using recycled powder from high plasticity index asphalt mixing plant according to claim 6, characterized in that: The preparation method of the composite silicon reinforcing agent comprises cooling the soil plugging agent, continuously stirring the silica sol and the KH550 coupling agent for at least 5 minutes, and maintaining the temperature at 50°C±5°C; and then cooling the obtained reaction solution to room temperature to obtain the composite silicon reinforcing agent.

9. The concrete using recycled powder from high plasticity index asphalt mixing plant according to claim 4, characterized in that: The collapse-preserving polycarboxylic acid water-reducing agent is a polycarboxylic acid water-reducing agent with a model of D0001 and a water-reducing rate of ≥25% produced by Shanxi Bajunma Building Materials Co., Ltd.

10. A method for preparing concrete using recycled powder from an asphalt mixing plant with a high plasticity index as claimed in any one of claims 1 to 9, characterized in that: The steps include: S1: dissolving the composite silicon strengthening agent in water to obtain a composite silicon strengthening agent solution; S2: Mix P·O42.5 grade cement, blast furnace slag powder, asphalt station recycled powder and fine aggregate evenly, then pour in the composite silicon strengthening agent solution and continue stirring for at least 2 minutes to obtain a mixture; S3: Add coarse aggregate and collapse-retaining polycarboxylate water-reducing agent into the mixture and continue stirring for 2 to 4 minutes to obtain concrete using recycled powder from a high plasticity index asphalt mixing station.

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