A kind of full solid waste pervious concrete and its preparation method

Abstract

The application provides a kind of full solid waste pervious concrete and its preparation method, and the raw material mass fraction of full solid waste pervious concrete includes waste concrete recycled coarse aggregate 65-70 parts, activated coal gangue composite precursor 20-25 parts, solid alkaline material 5-15 parts and water.The mass percentage of solid alkaline material in the mass of activated coal gangue composite precursor is 20-30%, and the mass percentage of water in the mass of activated coal gangue composite precursor is 30-40%;The activated coal gangue composite precursor specifically includes the following components by weight: activated coal gangue 60-75 parts;Fly ash 10-20 parts;Granulated blast furnace slag powder 10-25 parts;Water reducing agent 1-2 parts.The solid alkaline material specifically includes the following components by weight:Flaky sodium hydroxide 10-20 parts;Instant sodium silicate 30-40 parts;Alkaline residue micro powder 40-60 parts.The application has prepared pervious concrete with high strength and good water permeability.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of solid waste utilization, and in particular to a full-solid-waste pervious concrete and a preparation method thereof. BACKGROUND

[0002] The pervious concrete is an important component of the sponge city construction, has the characteristics of many pores, water permeability and air permeability, and is widely applied to sidewalks and parking lots. The pervious concrete on the market is prepared from cement as a cementing material and natural crushed stones as aggregates, consumes mineral resources, and increases carbon emission.

[0003] Solid wastes such as coal gangue, fly ash, granulated blast furnace slag powder and alkali residue are generated in industrial production, and are stacked in the open air, occupying land and polluting the environment. The waste concrete generated in the civil construction industry is difficult to dispose of, and needs to be recycled. SUMMARY

[0004] The application aims to solve the problems of insufficient utilization of solid wastes and insufficient consumption in the prior art, and provides a full-solid-waste pervious concrete and a preparation method thereof.

[0005] In a first aspect, the application provides a full-solid-waste pervious concrete, which is prepared from the following raw materials in mass parts: 65-75 parts of waste concrete recycled coarse aggregate, 20-30 parts of activated coal gangue composite precursor, 5-10 parts of solid alkaline material and water.

[0006] The activated coal gangue composite precursor specifically comprises the following components in parts by weight: 60-75 parts of activated coal gangue, 10-20 parts of fly ash, 10-25 parts of granulated blast furnace slag powder and 1-2 parts of water reducing agent.

[0007] The solid alkaline material specifically comprises the following components in parts by weight: 10-20 parts of flaky sodium hydroxide, 30-40 parts of instant sodium silicate and 40-60 parts of alkali residue micro powder.

[0008] Further, the waste concrete recycled coarse aggregate is a product obtained by crushing and screening waste concrete, and has a particle size range of 5-10 mm, a crushing value of less than 10% and a micro powder content of less than 1%.

[0009] Further, the activated coal gangue is a powder obtained by calcining water-washed coal gangue at 800-1000 DEG C, grinding and sieving to a particle size of less than 0.075 mm.

[0010] Further, the granulated blast furnace slag powder is a commercially available S95 grade granulated blast furnace slag powder.

[0011] Further, the fly ash is a commercially available secondary fly ash.

[0012] Further, the water reducing agent is a commercially available polycarboxylic acid high-performance water reducing agent.

[0013] Further, the flaky sodium hydroxide is commercially available flaky sodium hydroxide with a purity of 98%.

[0014] Further, the instant sodium silicate is commercially available instant sodium silicate with a purity of 95%.

[0015] Further, the alkali residue powder is an alkaline waste residue discharged in the process of industrial production of alkali and alkali treatment, and the mass ratio 10 times aqueous solution PH value is greater than 11.

[0016] In a second aspect, the application also provides a preparation method of the above-mentioned full-solid waste water-permeable concrete, comprising the following steps:

[0017] S1. Dry flaky sodium hydroxide, instant sodium silicate and alkali residue powder are weighed according to the proportion, put into a powder mixer for mixing, and a uniform solid alkaline material is obtained.

[0018] S2. Dry activated coal gangue, fly ash, granulated blast furnace slag powder and water reducing agent are weighed according to the proportion, put into a powder mixer for mixing, and a uniform activated coal gangue composite precursor is obtained.

[0019] S3. The solid alkaline material obtained in S1 is put into a concrete mixer, and water is added according to the proportion and stirred uniformly.

[0020] S4. The activated coal gangue composite precursor obtained in S2 is put into the S3 mixer according to the proportion, and stirred uniformly.

[0021] S5. Waste concrete recycled coarse aggregate is put into the S4 mixer according to the proportion, and stirred uniformly to obtain a full-solid waste water-permeable concrete product.

[0022] Further, the mixing time in step S1 is not less than 3 minutes, and the rotation speed is 20-30 rpm / min.

[0023] Further, the stirring time in step S2 is not less than 5 minutes, and the rotation speed is 20-30 rpm / min.

[0024] Further, the stirring time in step S3 is 3-5 minutes.

[0025] Further, the stirring time in step S4 is 3-5 minutes.

[0026] Further, the stirring time in step S5 is 2-3 minutes.

[0027] Coal gangue is a solid waste discharged in the process of coal mining and coal washing. High-temperature calcination can remove carbon components in coal gangue and hydroxyl groups contained in kaolinite, change Si-O structure and Al-O tetrahedral structure, and generate more Al2O3 and SiO2, thereby greatly improving the activation degree of coal gangue. The addition of fly ash and granulated blast furnace slag powder can adjust the fluidity and early strength of the pervious concrete.

[0028] The alkaline material can stimulate the mineral activity of the activated coal gangue composite precursor. When the alkali contacts the activated coal gangue composite precursor particles, OH - reacts with silicate on the surface of the fly ash particles, -Si-O-Si- or -Si-O-Al- in the silicate is broken, and active ions such as Si 4+ and Al 3+ are released, and different complexes such as [Al(OH)4] - , [Al(OH)6] 3- , [SiO(OH)3] - , [SiO(OH)2] 2- and [SiO3(OH)] 3- are formed. These substances are not stable and can further react with each other to form oligomeric gels. The oligomers combine with each other to form high-polymer gels with a three-dimensional network structure. Finally, the gels gradually harden to form cementitious materials.

[0029] The application has the following advantages: the application provides a full-solid-waste pervious concrete. The pervious concrete is prepared from activated coal gangue, fly ash, granulated blast furnace slag powder, solid alkaline material and water, and is supported by waste concrete recycled coarse aggregate. The raw materials jointly play a role. Compared with the prior art, the full-solid-waste pervious concrete has the following advantages:

[0030] (1) The pervious concrete provided by the application does not use cement in preparation. The mineral activity of activated coal gangue, fly ash and granulated blast furnace slag powder is stimulated by alkaline material, so that the material strength and water permeability rate meet the expected requirements, cost is saved, energy is saved, the environment is protected, and a new direction for the resource utilization of solid waste is provided.

[0031] (2) The pervious concrete provided by the application does not use natural aggregate in preparation, thereby reducing the use of natural resources.

[0032] (3) All materials except water in the preparation of the pervious concrete provided by the application are solid, and the preparation equipment is common equipment. The production method is simple and convenient for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1A flowchart of a preparation method of the full-solid-waste pervious concrete in the embodiments of the present application is shown. DETAILED DESCRIPTION

[0034] The present application will be further described in conjunction with the embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, and not limit the application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0035] The embodiments of the present application provide a full-solid-waste pervious concrete, and the raw materials include waste concrete recycled coarse aggregate, activated coal gangue composite precursor, solid alkaline material and water.

[0036] The raw material ratio of the activated coal gangue composite precursor is shown in Table 1.

[0037] Table 1 Raw material table of activated coal gangue composite precursor (by weight)

[0038]

[0039]

[0040] The raw material ratio of the solid alkaline material is shown in Table 2.

[0041] Table 2 Raw material table of solid alkaline material (by weight)

[0042] Raw materials Alkaline material 1 Alkaline material 2 Alkaline material 3 Alkaline material 4 Flaky sodium hydroxide 10％ 10％ 15％ 20％ Instant sodium silicate 30％ 35％ 35％ 40％ Alkaline residue micro powder 60％ 55％ 50％ 40％

[0043] The raw material ratio for preparing the full-solid-waste pervious concrete in the embodiments 1-50 of the present application is shown in Table 3.

[0044] Table 3 Raw material ratio table of full-solid-waste pervious concrete in embodiments 1-50 (by weight)

[0045]

[0046]

[0047] Further, the waste concrete recycled coarse aggregate is a product after the waste concrete is crushed and sieved, the particle size range of the waste concrete recycled coarse aggregate is 5-10 mm, the crushing value is less than 10%, and the micro powder content is less than 1%.

[0048] Further, the activated coal gangue is a powder with a sieved particle size less than 0.075 mm after the water-washed coal gangue is calcined at 800-1000℃ and finely ground.

[0049] Further, the granulated blast furnace slag powder is a commercially available S95 grade granulated blast furnace slag powder.

[0050] Further, the fly ash is commercially available secondary fly ash.

[0051] Further, the water reducing agent is commercially available polycarboxylic acid high-performance water reducing agent.

[0052] Further, the flaky sodium hydroxide is commercially available flaky sodium hydroxide with a purity of 98%.

[0053] Further, the instant sodium silicate is commercially available instant sodium silicate with a purity of 95%.

[0054] Further, the alkali residue powder is an alkaline waste residue discharged in the process of industrial production and alkali treatment, and the mass ratio 10 times aqueous solution PH value is greater than 11.

[0055] The preparation method comprises the following steps (see the specific flow chart Figure 1 ):

[0056] S1, the flaky sodium hydroxide, the instant sodium silicate and the alkali residue powder in dry state are weighed according to the proportion, and are put into a powder mixer for mixing, the mixing time is 2 minutes, and the rotating speed is 20-30 rpm / min, so that the uniform solid alkaline material is obtained;

[0057] S2, the activated coal gangue, the fly ash, the granulated blast furnace slag powder and the water reducing agent in dry state are weighed according to the proportion, and are put into a powder mixer for mixing, the stirring time is 5 minutes, and the rotating speed is 20-30 rpm / min, so that the uniform activated coal gangue composite precursor is obtained;

[0058] S3, the solid alkaline material obtained in S1 is put into a concrete mixer, water is added according to the proportion, and is stirred uniformly, and the stirring time is 4 minutes;

[0059] S4, the activated coal gangue composite precursor obtained in S2 is put into the S3 mixer according to the proportion, and is stirred uniformly, and the stirring time is 4 minutes;

[0060] S5, the waste concrete recycled coarse aggregate is put into the S4 mixer according to the proportion, and is stirred uniformly to obtain the full-solid-waste pervious concrete product, and the stirring time is 2 minutes;

[0061] S6, the pervious concrete prepared in each embodiment is put into a 100mm*100mm*100mm mold to form a test block, after standard curing for 28 days, the slump, the initial setting time, the compressive strength and the water permeability coefficient of the pervious concrete are tested.

[0062] Performance test

[0063] The performance of the full solid waste pervious concrete products prepared in Examples 1-50 was tested, wherein the slump, initial setting time was tested according to the standard GBT 50080-2016 ordinary concrete mixture performance test method, the compressive strength was tested according to the standard GB / T500-81-2002 ordinary concrete mechanical property test method, and the permeability coefficient was tested according to the standard CJJ / T135-2009 Technical Specification for Pervious Cement Concrete Pavement (2023 edition); the specific test results are shown in Table 4.

[0064] Table 4 Performance test results of Examples 1-50

[0065]

[0066]

[0067]

[0068] As can be seen from Table 4, the full solid waste pervious concrete provided by the present application has the following characteristics:

[0069] (1) 28-day compressive strength > 20 MPa, meeting the required strength of the surface layer material;

[0070] (2) Slump < 50 mm, initial setting time > 120 min, with good workability, facilitating construction;

[0071] (3) Permeability coefficient > 2, meeting the permeability requirement.

[0072] Based on the performance test results of Examples 1-50, it is found that the increase of the amount of coarse aggregate slightly reduces the strength of the concrete, but does not significantly affect the permeability coefficient. The performance test results of the examples show that the mass fraction of coarse aggregate is 65%-70%, which can meet the requirements of permeability rate and strength. The components of alkaline materials have certain influence on the slump, initial setting time, compressive strength and permeability coefficient of the pervious concrete. Alkaline slag micro powder can improve the strength and increase the permeability rate, but will increase the cost, which should be considered as a whole. The greater the amount of granulated blast furnace slag powder in the activated coal gangue composite precursor, the higher the strength, but the cost will increase.

[0073] The principles and implementation manners of the present application are described by using specific examples in the present article, and the above example descriptions are only used to help understand the method of the present application and its core idea. The above descriptions are only the preferred implementation manners of the present application. It should be noted that, due to the limited nature of the language expression, there are objectively infinite specific structures, and for ordinary skilled persons in the technical field, some improvements, refinements or changes can be made without departing from the principles of the present application, or the above technical features can be combined in an appropriate manner; these improvements, refinements, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, shall be regarded as the protection scope of the present application.

Claims

1. A full-solid waste pervious concrete, characterized by, The raw material quality parts include 65-70 parts of waste concrete recycled coarse aggregate, 20-25 parts of activated coal gangue composite precursor, 5-15 parts of solid alkaline material and water; The mass percentage of the solid alkaline material in the mass of the activated coal gangue composite precursor is 20-30%, and the mass percentage of water in the mass of the activated coal gangue composite precursor is 30-40%. The activated coal gangue composite precursor specifically includes the following components by weight: 60-75 parts of activated coal gangue; 10-20 parts of fly ash; 10-25 parts of granulated blast furnace slag powder; and 1-2 parts of water reducing agent. The solid alkaline material specifically includes the following components by weight: 10-20 parts of flaky sodium hydroxide; 30-40 parts of instant sodium silicate; and 40-60 parts of alkali residue micro powder. The waste concrete recycled coarse aggregate is a product obtained by crushing and screening waste concrete, and has a particle size range of 5-10 mm, a crushing value less than 10%, and a micro powder content less than 1%. The activated coal gangue is a powder obtained by calcining water-washed coal gangue at 800-1000°C, and then grinding and sieving to a particle size less than 0.075 mm. The granulated blast furnace slag powder is a commercially available S95 grade granulated blast furnace slag powder. The fly ash is a commercially available secondary fly ash. The water reducing agent is a commercially available polycarboxylic acid high-performance water reducing agent. The flaky sodium hydroxide is a commercially available flaky sodium hydroxide with a purity of 98%. The instant sodium silicate is a commercially available instant sodium silicate with a purity of 95%.

2. A method of preparing a full-solid waste pervious concrete as claimed in claim 1, characterized by, The method includes the following steps: S1. Dry flaky sodium hydroxide, instant sodium silicate and alkali residue micro powder are weighed in proportion and put into a powder mixer to mix, obtaining a uniform solid alkaline material; S2. Dry activated coal gangue, fly ash, granulated blast furnace slag powder and water reducing agent are weighed in proportion and put into a powder mixer to mix, obtaining a uniform activated coal gangue composite precursor; S3. The solid alkaline material obtained in S1 is put into a concrete mixer, and water is added in proportion and stirred uniformly; S4. The activated coal gangue composite precursor obtained in S2 is put into the S3 mixer in proportion, and stirred uniformly; S5. Waste concrete recycled coarse aggregate is put into the S4 mixer in proportion, and stirred uniformly to obtain a full-solid-waste permeable concrete product.

3. The method of claim 2, wherein the full-solid waste pervious concrete is prepared by mixing the full-solid waste, the cement, the fine aggregate, the coarse aggregate, the water, and the superplasticizer. The stirring time in step S2 is not less than 5 minutes at a speed of 20-30 rpm / min. The stirring time in step S3 is 3-5 minutes. The stirring time in step S4 is 3-5 minutes. The stirring time in step S5 is 2-3 minutes.

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