Fine-grained high-density concrete and production process thereof

Abstract

The invention discloses fine-grained high-compactness concrete and a production process thereof, and relates to the technical field of concrete. The anti-shrinkage cement mortar comprises a solid particle material, cement, water and a nano anti-shrinkage additive, the weight of the solid particle material with the unit volume of 1m < 3 > is taken as a reference, and the weight ratio of the components is GA: Gc: Gjs: Ga; wherein GA is the weight of the solid particle material in unit volume, Gc is the weight of cement filled in the void volume of the solid particle material of the weight GA, Gjs is the weight of additional water, and the sum of the weight of water required by cement hydration and rheological property before concrete solidification of the weight GA is subtracted from the weight of water contained in the solid particle material of the weight GA; ga is the weight of the nano anti-shrinkage additive added and filled in the pore volume of the hydrated pores of the cement except the excess free water volume. The porosity of the fine-grained high-density concrete is far smaller than that of common concrete, and the compression resistance, fracture resistance and durability of the concrete are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete, and particularly relates to a fine aggregate high-density concrete and its production process. Background Art

[0002] Concrete is one of the most important civil engineering materials in modern times and is an important building material, widely used in fields such as construction, roads, and bridges. Traditional concrete is formed by mixing cementitious materials, aggregates, water, and admixtures according to volume-weight ratios, and through mechanical stirring to achieve homogenization, fluidity, and plasticity, and then hardening to form artificial stone, which is widely used in construction projects. Cement bonds the aggregates into a whole through hydration reactions; fine aggregates (sand) fill the gaps between coarse aggregates to improve density, and coarse aggregates (stones) form the skeleton to bear the main load; water triggers the cement hydration reaction, and admixtures optimize the performance. Different structures require concrete to meet the "four major performances": workability (slump, density); durability (impermeability, frost resistance, abrasion resistance, air void spacing factor, chloride ion penetration resistance, sulfate attack resistance, dry shrinkage test); physical and chemical properties (apparent density, air content, chloride ion content, setting time); mechanical properties (compressive strength, flexural strength, splitting tensile strength, elastic modulus).

[0003] The traditional concrete mix ratio adopts the volume-weight method and is calculated by assuming a concrete unit weight of 2400 kg / m 3 Specific steps include: first, according to the concrete grade, slump, and durability requirements to be proportioned, look up the table to obtain the cement dosage, water-cement ratio, and sand ratio, and then based on the total unit weight of cement, sand, stone, and water in the concrete of 2400 kg / m 3 , calculate and determine the weights of cement, yellow sand, gravel, and water per cubic meter of concrete to obtain the calculated mix ratio for concrete production; use the calculated mix ratio to produce concrete specimens, and through the test and analysis of the workability, durability, and mechanical properties of the specimen concrete, adjust the gravel gradation, sand ratio, water, and admixture dosages, and finally obtain the production mix ratio through experimental verification.

[0004] However, a large amount of sand and stone materials are required in concrete production. The exploitation of sand and stone materials damages the environment and consumes resources, which is not conducive to environmental protection. The production of fine aggregate high-density concrete can eliminate the need for sand and stone materials. In concrete production, particulate materials with a particle size less than 5 mm are usually used, and generally refer to inorganic solid waste materials mainly composed of fine particles, which widely include various inorganic fine-grained particulate materials such as construction waste soil, completely weathered rock, strongly weathered rock, aeolian sand, stone powder, various soils, and mine tailings. This can abandon the sand and stone aggregates that must be used in traditional concrete production, make full use of waste soil, tailings, and construction waste for concrete production, be beneficial to environmental protection, save resources, and can greatly reduce production costs, which is a production model of low-carbon and resource recycling economy.

[0005] However, the existing concrete mix design method cannot be used for the preparation of concrete with inorganic solid waste materials mainly composed of fine particles. For environmental protection and improving the utilization rate of resources, the present invention provides a fine-aggregate high-density concrete and its production process. Summary of the Invention

[0006] (I) Technical problems to be solved

[0007] In view of the deficiencies of the prior art, the present invention provides a fine-aggregate high-density concrete and its production process, which solve at least one of the technical problems raised in the background art.

[0008] (II) Technical solutions

[0009] To achieve the above object, the technical solution adopted by the present invention is: In a first aspect, a high-performance concrete prepared from construction waste is provided. The fine-aggregate high-density concrete includes solid particle materials, cement, water, and a nano anti-shrinkage additive; Among them, for the solid particle materials, cement, water, and nano anti-shrinkage additive, based on the weight of the solid particle materials per unit volume of 1 m 3 , the weight ratios of the components are G A : G c : G js : G a； Wherein, G A is the weight of the natural solid particle materials per unit volume, G c is the weight of the cement filled in the void volume of the solid particle materials with a weight of G A , G js is the weight of the externally added water, G js = G wx - G wh , where G wx is the sum of the weight of the water required for the hydration of the cement with a weight of G c and the rheology of the concrete before curing, G wh is the natural water content of the solid particle materials with a weight of G A ; G a is the weight of the nano anti-shrinkage additive that can be added and filled in the cement pores after removing the volume occupied by the free water in the porosity.

[0010] Preferably, when the unit volume of the solid particle materials is 1 m 3 , its unit pore volume Vp A = 1×(1 - ρ A / d A ), where ρ A is the dry bulk density of the solid particle materials, with the unit of kg / m 3 ; d Ais the specific gravity of solid granular material, in kg / m 3 .

[0011] Preferably, the weight of the cement G c =Vp A ·ρ c =1×(1-ρ A / d A )·ρ c , unit is kg.

[0012] Preferably, the pore volume Vp of the cement c =G c / ρ c × (1-ρ c / d c ) = 1 × (1-ρ A / d A )×(1-ρ c / d c ),ρ c is the dry bulk density of cement, d c is the specific gravity of cement, in kg / m 3 , Vp c is the weight G c The pore volume of solid granular material, in m 3 .

[0013] Preferably, the G c Weight of water required for cement hydration G w =0.23G c ; and considering the evaporation loss of water during the concrete preparation and mixing process and the sum of water required for rheological properties before solidification G wx = (0.25~0.50) Gc, the unit is kg.

[0014] Preferably, the G c The weight of the cement pore volume is the weight of the free water volume that is not combined in the process of forming concrete. The remaining pore volume should be filled with nano anti-shrinkage additives. The nano anti-shrinkage additives can be inorganic materials such as calcium sulfoaluminate, calcium oxide, magnesium oxide, fly ash, silica fume, or a mixture of one or more of the organic materials such as polyether and alkyl alcohol, or an inorganic-organic composite of one or more of the above materials.

[0015] Preferably, after the fine-grained high-density concrete is cured, the weight of the remaining free water in the pores of the concrete is G wy =(0.02~0.27)G c , in kg; the volume of free water in the pores of concrete after cement solidification V wy =(0.02~0.27)G c / ρw , where ρ w is the theoretical unit weight of water, taking 1000 kg / m 3 .

[0016] Preferably, the filling volume Vp of the nano anti-shrinkage additive cy = Vp c - V wy in unit of m 3 ; the weight G of the nano anti-shrinkage additive material a = ρ a ·Vp cy , in unit of kg, where ρ a is the unit weight of the nano anti-shrinkage additive material, in unit of kg / m 3 .

[0017] Preferably, the weight of the externally added water G js = G wx - G wh ; the G wx is the sum of the water required for the hydration of G c weight cement and the water required for the preparation and mixing of concrete; G wh is the natural water content weight in the solid particle material of weight G A .

[0018] Preferably, the solid particle material is a particle material with a particle size less than 5 mm, including any one or more of waste soil, completely weathered rock, strongly weathered rock, aeolian sand, stone powder, various soils and mine tailings.

[0019] There is also provided a production process for fine aggregate high-density concrete, and the production process includes the following steps: Step S1: The solid particle material passes through a hammer crusher with a rotational speed greater than 300 r / min and an impact hammer force of 50 - 500 KN to ensure that the particle material will not be broken down any further under a pressure of 50 - 200 Mpa compressive strength; Step S2: For the crushed solid particle material, the water content, unit weight, dry density, and specific gravity are tested, and the dry unit weight and specific gravity of the cement and nano anti-shrinkage additive used are tested; Step S3: The mix ratio of the materials used is calculated and verified through sample tests to determine the concrete mix ratio; Step S4: Calculate the usage amounts of various materials according to the mix ratio, and the metered crushed raw materials enter a multi-source coupling powerful mixer of vane type, anchor type or turbine type with a rotational speed of 100 - 800 revolutions per minute under ultrasonic, vibration, and negative pressure environments; Step S5: Add the metered cement, water, and admixture into the mixer. First, turn on the vacuum switch, maintain the negative pressure at -0.02 to -0.09 Mpa, and continuously evacuate for 0.5 to 1 minute. Then, turn on vibration and high-speed stirring, and keep vibrating, stirring, and evacuating simultaneously for 3 to 4 minutes. Then, stop evacuating and open the vacuum relief valve, but continue stirring for 0.5 to 1 minute until the pressure in the cylinder returns to normal, thus completing the concrete mixing. The finished concrete is discharged from the mixer.

[0020] (III) Beneficial Effects

[0021] The present invention provides a fine aggregate high-density concrete and its production process. Compared with the prior art, it has the following beneficial effects: (1) The porosity of the fine aggregate high-density concrete of the present invention is much smaller than that of ordinary concrete. The porosity is generally less than 5%. The durability is greatly improved. The impermeability under the same compressive strength grade is increased by more than 3 to 5 grades, the flexural strength and bending strength are increased by more than 2 times, and the elongation and shrinkage rate are increased by more than 10 times. The production cost is reduced by more than 25%.

[0022] (2) Through the theoretical algorithm of the unit pore volume densification method, the present invention can control and reduce the porosity of concrete to the greatest extent, optimize the concrete performance, accurately match the materials, optimize the material dosage, and further achieve the dispersion and densification of the mixed materials through multi-source coupling stirring, reduce the weak structural links after cement solidification, and significantly improve the compressive, flexural, and durability performance of concrete. Description of the Drawings

[0023] The following further illustrates the present invention in conjunction with the drawings and embodiments: Figure 1 It is a schematic diagram of the production process flow of the embodiment of the present invention. Detailed Embodiments

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] To better understand the above technical solutions, the above technical solutions will be described in detail below in conjunction with the drawings of the specification and specific embodiments: In a first aspect, an embodiment of the present invention provides a fine-aggregate high-density concrete, which includes solid granular materials, cement, water, and a nano anti-shrinkage additive; the mix ratio is calculated according to the principle of unit pore volume densification method; specifically, the nano anti-shrinkage additive can be a nano inorganic anti-shrinkage additive.

[0026] Among them, for the solid granular materials, cement, water, and nano anti-shrinkage additive, with the unit volume of the solid granular materials being 1 m 3 as the weight reference, the weight ratio of each component is G A :G c :G js :G a； wherein, G A is the weight of the natural solid granular materials per unit volume, G c is the weight of the cement filled in the void volume of the solid granular materials with the weight of G A , G js is the weight of the externally added water, G js = G wx - G wh , where G wx is the sum of the water weights required for the hydration of the cement with the weight of G c and the rheology before the curing of the concrete, G wh is the natural water content of the solid granular materials with the weight of G A ; G a is the weight of the nano anti-shrinkage additive that can be added and filled in the cement pores after removing the volume occupied by the free water in the porosity.

[0027] Specifically, the above solid granular materials are granular materials with a particle size less than 5 mm, including any one or more of waste soil, fully weathered rock, strongly weathered rock, aeolian sand, stone powder, various soils, and mine tailings.

[0028] In the above embodiment, the solid granular materials are used as the particle filling materials of the concrete, which are actually fine materials. The embodiment of the present invention focuses on the production of fine-aggregate high-density concrete using these solid waste materials. The embodiment of the present invention proposes a "pore volume densification method" for mix ratio calculation theory and a production process for fine-aggregate high-density concrete. Through the theoretical algorithm of the unit pore volume densification method, the porosity of the concrete can be controlled and reduced to the greatest extent, the concrete performance can be optimized, the material ratio can be accurately determined, the material usage can be optimized, and the compressive, flexural, and durability performances of the concrete can be significantly improved.

[0029] For the pore volume densification method proposed in the embodiment of the present invention, the mix ratio calculation method is to calculate the sample raw materials such as solid granular materials, cement, water, and nano anti-shrinkage additive according to the following steps: (1)Prepare a specimen of the solid particulate material first. This specimen material is sampled from the raw material A used in production, and then its natural bulk density γ A (kg / m 3 ), moisture content ω A (%), dry bulk density ρ A (kg / m 3 ), and specific gravity d A (kg / m 3 ) are measured according to the national standard method GB / T 16913-2008 "Test Methods for Physical Properties of Dust"; (2) According to the porosity calculation formula: P = (1 - ρ / d) × 100%; (3) Assume that when the unit volume of the fine aggregate raw material A is 1 m 3 , its unit pore volume Vp A = 1×(1 - ρ A / d A ) (m 3 ); (4) The calculation theory of the pore volume compaction method is that the voids in the unit volume of material A should be filled with cement and water of smaller particle sizes. The dry bulk density ρ c (kg / m 3 ) and specific gravity d c (kg / m 3 ) of the cement are measured by experiments. The theoretical bulk density ρ w of water = 1000 kg / m 3 . According to the pore filling theory of the pore volume compaction method: the pore volume Vp<00001'specimen material is sampled from the raw material A used in production, and then its natural bulk density γ A (kg / m 3 ), moisture content ω A (%), dry bulk density ρ A (kg / m 3 ), and specific gravity d A (kg / m 3 ) are measured according to the national standard method GB / T 16913-2008 "Test Methods for Physical Properties of Dust"; (2) According to the porosity calculation formula: P = (1 - ρ / d) × 100%; (3) Assume that when the unit volume of the fine aggregate raw material A is 1 m 3 , its unit pore volume Vp A = 1×(1 - ρ A / d A ) (m 3 ); (4) The calculation theory of the pore volume compaction method is that the voids in the unit volume of material A should be filled with cement and water of smaller particle sizes. The dry bulk density ρ c (kg / m 3 ) and specific gravity d c (kg / m 3 ) of the cement are measured by experiments. The theoretical bulk density ρ w of water = 1000 kg / m 3 . According to the pore filling theory of the pore volume compaction method: the pore volume Vp A = 1×(1 - ρ A / d A ) (m 3 ), and after calculation, the required cement weight G c = Vp A ·ρ c = 1×(1 - ρ A / d A )·ρ c (kg); the pore volume Vp c in the cement with weight G c = G c / ρ c ×(1 - ρ c / d c ) = 1×(1 - ρ A / d A )×(1 - ρ c / d c ) (m 3 ), where ρ c is the dry bulk density of the cement and d c is the specific gravity of the cement, with the unit of kg / m3 , Vp c is the weight G c The pore volume of solid granular material, in m 3 .

[0030] (5) The test shows that after hydration, cement forms hydrated compounds, the bound water of which is 23% of the weight of cement. A Assuming the weight of the filling cement G c (kg), then the weight of water required for hydration is G w =0.23G c (kg). In order to ensure that the cement is fully hydrated and to prevent the evaporation loss of water molecules during concrete mixing, and to meet the rheological requirements before solidification, the water consumption can be slightly increased when calculating the mix ratio. The required water consumption G wx =(0.25~0.50)G c (kg). Unit volume 1m 3 Fine aggregate raw material A weight G A , its natural bulk density γ A , moisture contentω A , dry bulk density ρ A , the unit volume is 1m 3 When the natural weight G A =1 · γ A (kg), including the weight of water G wh =ω A· G A (kg), then the additional water consumption G in the mix ratio calculation of fine aggregate raw material A is js =G wx -G wh =(0.25~0.50)G c -ω A· G A (kg), G wx G c The sum of the weight of water required for cement hydration and concrete preparation and mixing; G wh is the weight G A The natural water content weight in the solid particulate material, taking into account the evaporation of water during mixing, should not be less than 0.25, within the range of (0.25 to 0.50), and should be determined by the specific adjustment during the mix ratio test based on the required working performance.

[0031] (6) G cExcept for the volume of free water that has not reacted during the formation of concrete, the remaining pore volume in the heavy cement should be filled with a nano anti-shrinkage additive. The nano anti-shrinkage additive can be one or several inorganic materials such as calcium sulfoaluminate, calcium oxide, magnesium oxide, fly ash, silica fume, etc., or one or several organic materials such as polyethers and alkyl alcohols, or an inorganic-organic composite of the above one or several materials.

[0032] (7) The pore volume Vp in the cement used c After removing the free water volume V wy There is still a remaining pore volume Vp cy = (Vp c - V wy ) (m 3 ), which is filled with a nano anti-shrinkage additive with a finer particle size. The bulk density ρ a (kg / m 3 ) of the nano anti-shrinkage additive material, and the weight G a of the nano anti-shrinkage additive = ρ a· Vp cy (kg), that is: G a = ρ a · Vp cy = ρ a · (Vp c - V wy ) = ρ a · {1 × (1 - ρ A / d A ) × (1 - ρ c / d c ) - [(0.25~0.50) - 0.23]G c / ρ w} (kg), and it can be completely filled; Among them, the weight G wy of the remaining free water in the pores inside the concrete after the fine aggregate high-density concrete solidifies = (0.02~0.27)G c , with the unit of kg; the volume V wy of the free water in the pores inside the concrete after the cement solidifies = G wy / ρ w = (0.02~0.27)G c / ρ w Among them, ρ w is the theoretical bulk density of water, taking 1000 kg / m 3 .

[0033] (8) The nano anti-shrinkage additive in the above is one or a mixture of several materials such as ettringite, aluminum sulfate, aluminum oxide, calcium sulfate, potassium alum, calcium oxide, silicon oxide, magnesium oxide, etc. Its production process is to crush at room temperature and then calcine at a high temperature of ≥1300 °C for 0.5 - 2 h and then rapidly cool, and then crush again. First, use a jaw crusher or hammer crusher with a crushing force ≥50 KN for crushing, and finally use air crushing. The air crushing parameters are: air pressure ≥0.5 MPa, wind speed ≥50 m / s, impact frequency ≥2000 times / min, and particle diameter ≤600 nm.

[0034] According to the above "pore volume densification method" theory, the usage amounts of various materials required for producing concrete from raw materials were calculated for 1 m of dense pores. 3 The usage amount of each material required for producing concrete from raw materials, and the calculation results are respectively: "cement weight G c ", "natural weight G of fine aggregate A A ", "calculated water consumption G js ", "nano anti-shrinkage additive G a "; and a high-performance water reducer such as polycarboxylic ether graft copolymer (or naphthalene sulfonate formaldehyde condensate, melamine sulfonate condensate) is added at 0.5 - 5% of the cement weight.

[0035] Based on the above mix ratio, concrete specimens were trial-mixed. During the specific implementation process, according to the requirements of the workability, durability and mechanical properties of the concrete, the water consumption, the weight of the nano-inorganic additive and the addition amount of the high-performance water reducer were slightly adjusted to obtain the final production mix ratio.

[0036] Further, the production process includes the following steps: For various inorganic fine-grained particulate materials such as waste soil, fully weathered rock, strongly weathered rock, aeolian sand, stone powder, various soils, mine tailings, etc., which may contain agglomerated and low compressive strength blocks, in order to ensure the durability and mechanical property indexes of the concrete, the fine aggregate particles must be crushed and decomposed into the smallest particles, and the particles must meet the compressive index above the design strength of the concrete and not continue to decompose. Of course, in the actual production process, the particle size of the raw materials is not required, and it is only necessary to control the particle size to be less than 5 mm during the preparation process.

[0037] Therefore, for soft rock, completely weathered rock, strongly weathered rock, construction solid waste, aeolian sand, stone powder, mine tailings and various kinds of waste soil, they can be first strongly crushed by a hammer crusher or jaw crusher with an impact force of 50 - 500 KN; then enter a multi-source coupling mixer with strong stirring, vibration and negative pressure coupling of blade paddle type, anchor type or turbine type for strong stirring. The rotational speed of the multi-source coupling mixer is 100 - 800 r / min, the amplitude is 0.5 - 2.0 mm, the vibration frequency is 170 - 220 Hz, and the pressure is -0.01 - -0.09 Mpa. All kinds of waste solid materials after hammer crushing enter the multi-source coupling mixing equipment and are mixed with cement, water, nano anti-shrinkage additive and high-range water reducer for 4 - 6 minutes. The technological process is as Figure 1 shown.

[0038] The specific steps are as follows: (1) For various waste solid materials such as muck, they can be first passed through a hammer crusher with a rotational speed greater than 300 r / min and an impact hammer force of 50 - 500 KN to ensure that the granular materials will not be broken down again under a pressure of 50 - 200 Mpa of compressive strength; (2) Test the moisture content, bulk density, dry density and specific gravity of the crushed raw materials, and test the dry bulk density and specific gravity of the used cement and nano anti-shrinkage additive; (3) Calculate the mix proportion of the used materials and verify it through sample tests to determine the concrete mix proportion; (4) Calculate the usage amount of various materials according to the mix proportion, and the metered crushed raw materials enter a blade type or turbine type strong mixer with a rotational speed of 100 - 800 r / min; (5) At the same time, add the metered cement, water and various admixtures into the mixer. First, turn on the vacuum pump switch, keep the negative pressure at -0.02 - -0.09 Mpa and continuously evacuate for 0.5 - 1 minute, then turn on the vibration and high-speed stirring, keep stirring while vibrating and evacuating for 3 - 4 minutes, then stop evacuating, open the vacuum relief valve, but continue to stir for 0.5 - 1 minute until the pressure in the cylinder returns to normal, that is, the concrete mixing is completed, and the finished concrete is discharged from the mixer.

[0039] The beneficial effects of this production process are as follows: Through multi-source coupling stirring, the mixed materials can be further dispersed and compacted, reducing the weak links in the structure after cement solidification, and significantly improving the compressive, flexural and durability performance of concrete; specifically, high-speed paddle stirring or turbine stirring can improve the destructive force of the agglomeration of fine-grained raw materials and the uniformity of mixing; vibration stirring can break the agglomeration of particles, reduce the segregation phenomenon, and improve the stirring efficiency; negative pressure stirring can effectively inhibit dust, reduce bubbles and save cementitious materials. The addition of nano anti-shrinkage additive can effectively resist the dry shrinkage phenomenon during the solidification and use of concrete, and eliminate the deformation defects of concrete under non-load conditions.

[0040] The porosity of fine aggregate high-density concrete is much smaller than that of ordinary concrete, generally less than 5%, resulting in a significant improvement in durability. The impermeability under the same compressive strength grade is increased by more than 3 to 5 grades, the flexural and bending strengths are increased by more than 2 times, the extension and shrinkage rate are increased by more than 10 times, and the production cost is reduced by more than 25%.

[0041] Furthermore, detailed embodiments are provided for specific illustration: The technical calculation process of the present invention is relatively cumbersome and there are many embodiments and comparative examples. Therefore, copper mine fine tailings are selected as an example for the solid particle material. According to the principle of the unit pore volume densification method, the mix ratio is calculated. The detailed calculation process is as follows: After measurement, the natural bulk density γ of copper mine fine tailings A = 1526 (kg / m 3 ), the water content ω A = 9.3%, the dry bulk density ρ A = 1396 (kg / m 3 ), and the specific gravity d A = 3086 (kg / m 3 ); the dry bulk density ρ of 425# Portland cement c = 1172 (kg / m 3 ), the specific gravity d c = 3153 (kg / m 3 ); the ρ of the nano anti-shrinkage additive a = 909.6 (kg / m 3 ).

[0042] ① Take 1 m³ of copper mine fine tailings. Its unit pore volume Vp A = 1×(1 - ρ A / d A ) = 0.548 (m 3 ), and its weight G A = γ A V A = 1×1526 = 1526 (kg); ② The weight of cement required G c = Vp A ·ρ c = 0.548×1172 = 642 (kg); ③ Then the pore volume of cement is Vp c = G c / ρ c ×(1 - ρ c / d c ) = Vp A ×(1 - ρ c / dc ) = 0.548 × (1 - 1172 / 3153) = 0.344(m 3 ); ④ The weight of bound water required for cement hydration, G w = 0.23G c = 148 (kg). To ensure full hydration of the cement and prevent evaporation loss of water molecules during concrete mixing, and to ensure a slump of 80 - 100 mm, when calculating the mix ratio, the water consumption is taken as G wx = 0.40G c = 0.40 × 642 = 257 (kg), the weight of free water, G wy = G wx - G w = 109 (kg); ⑤ The weight of water contained in the raw material copper mine fine tailings, G wh = ω A G A = 9.3% × 1526 = 142 (kg); ⑥ The calculated additional water consumption, G, in the mix ratio calculation of copper mine fine tailings js = G wx - G wh = 115 (kg), the free water volume, V The free water volume, V wy = G wy / ρ w = 0.109 m 3 , the pore volume, V pc in the cement used, after removing the free water volume, V wy , there is still a remaining pore volume, Vp cy = Vp c - V wy = 0.344 - 0.109 = 0.235 (m 3 ); ⑦ The remaining volume is filled with a nano anti - shrinkage additive, then the weight of the nano anti - shrinkage additive, G a = ρ a· Vp cy = 909.6 × 0.235 = 214 (kg). The nano anti - shrinkage additive used in this project is actually expansive cement, which can replace cement in use. Therefore, the actual cement consumption can be adjusted to G c ， = 642 - 214 = 428 (kg). At this time, the porosity of the cement, Vp c ， = G c / ρ c × (1 - ρ c / d c) = 428 / 1172 × 0.628 = 0.229 (m 3 ) ≥ 0.109 (m 3 ), the scheme is feasible; The polycarboxylate superplasticizer is 0.5% of the total cement consumption, that is, 642 × 0.5% = 3.2 (kg). Calculated according to the actual water reduction of 13%, the actual water consumption G ’ js = 115 × (1 - 13%) = 100 (kg). After calculation, the actual mix ratio is as follows: Natural state copper mine fine tailings: Cement: Nano anti - shrinkage additive: External added water: Superplasticizer is 1526 kg: 428 kg: 214 kg: 100 kg: 3.2 kg.

[0043] The following Table 1 shows the specific process parameters, raw materials and mix ratios of Example 1, Example 2, Example 3, and Example 4, as well as the performance parameters of the prepared concrete; Example 1 prepares concrete using copper mine fine tailings from Chuzhou, Anhui as raw materials: Process steps: The copper mine fine tailings are first crushed by a hammer crusher to ensure that the granular materials will not be further broken and decomposed under a compressive strength of 50 Mpa. Measure the moisture content, bulk density, dry density, and specific gravity of the crushed copper mine fine tailings, and measure the dry bulk density and specific gravity of the used cement and nano anti - shrinkage additive. Calculate the usage amount of various materials according to the technology of the present invention (for detailed calculation, refer to the above - mentioned calculation process of copper mine fine tailings). Measure various materials according to the mix ratio of natural state copper mine fine tailings: Cement: Nano anti - shrinkage additive: External added water: Superplasticizer = 1526 kg: 428 kg: 214 kg: 100 kg: 3.2 kg. Put the measured crushed raw materials into a blade - type powerful mixer with a rotation speed of 800 revolutions per minute. At the same time, add the measured cement, water, and various admixtures into the mixer. Turn on the vacuum pump switch and continuously evacuate for 1 minute, with the negative pressure maintained at - 0.09 Mpa. Then turn on the vibration and stir for 3 minutes while evacuating. Then stop evacuating, open the vacuum relief valve, but continue to stir for 0.5 minutes until the pressure in the cylinder returns to normal, that is, the concrete mixing is completed. The finished concrete is discharged from the mixer, put into molds for curing, and the corresponding parameters are measured.

[0044] Example 2 prepares concrete using strongly weathered phyllite from Tibetan areas in Sichuan as raw materials: Process steps: The strongly weathered phyllite is first crushed by a hammer crusher to ensure that the granular material will not be further crushed and decomposed under a compressive strength of 50 Mpa; measure the moisture content, bulk density, dry density, and specific gravity of the crushed strongly weathered phyllite, and measure the dry bulk density and specific gravity of the cement and nano anti-shrinkage additive used; calculate the usage amount of various materials according to the technology of the present invention (for detailed calculation, refer to the above-mentioned calculation process of copper mine fine tailings); measure various materials according to the mix ratio of naturally occurring strongly weathered phyllite:cement:nano anti-shrinkage additive:external water:water reducer = 1762 kg:441 kg:81 kg:147 kg:2.2 kg. Put the measured crushed raw materials into a blade-type powerful mixer with a rotation speed of 800 revolutions per minute. At the same time, add the measured cement, water, and various external admixtures into the mixer. Turn on the vacuum pump switch and continuously evacuate for 1 minute, with the negative pressure maintained at -0.09 Mpa. Then turn on the vibration and stir for 3 minutes while evacuating. Then stop evacuating, open the vacuum relief valve, but continue to stir for 0.5 minutes until the pressure in the cylinder returns to normal, thus completing the concrete mixing. The finished concrete is discharged from the mixer, placed in a mold for curing, and the corresponding parameters are measured.

[0045] Example 3: Prepare concrete using strongly weathered mudstone in Tibetan areas of Sichuan as raw material: Process steps: The strongly weathered mudstone is first crushed by a hammer crusher to ensure that the granular material will not be further crushed and decomposed under a compressive strength of 50 Mpa; measure the moisture content, bulk density, dry density, and specific gravity of the crushed strongly weathered mudstone, and measure the dry bulk density and specific gravity of the cement and nano anti-shrinkage additive used; calculate the usage amount of various materials according to the technology of the present invention (for detailed calculation, refer to the above-mentioned calculation process of copper mine fine tailings); measure various materials according to the mix ratio of naturally occurring strongly weathered mudstone:cement:nano anti-shrinkage additive:external water:water reducer = 1927 kg:415 kg:138 kg:59 kg:2.1 kg. Put the measured crushed raw materials into a blade-type powerful mixer with a rotation speed of 800 revolutions per minute. At the same time, add the measured cement, water, and various external admixtures into the mixer. Turn on the vacuum pump switch and continuously evacuate for 1 minute, with the negative pressure maintained at -0.09 Mpa. Then turn on the vibration and stir for 3 minutes while evacuating. Then stop evacuating, open the vacuum relief valve, but continue to stir for 0.5 minutes until the pressure in the cylinder returns to normal, thus completing the concrete mixing. The finished concrete is discharged from the mixer, placed in a mold for curing, and the corresponding parameters are measured.

[0046] Example 4: Prepare concrete using solid waste red mud from alumina tailings in Pingguo City, Guangxi as raw material: Process steps: The red mud is first crushed by a hammer crusher to ensure that the granular material will not break down and decompose under the compressive strength of 50Mpa; the moisture content, bulk density, dry density, and specific gravity of the crushed red mud are measured, and the dry bulk density and specific gravity of the cement and nano anti-shrinkage additive used are measured; the amount of each material used is calculated according to the technology of the present invention (for detailed calculation, refer to the above copper mine fine tailings calculation process); according to the mix ratio of natural state red mud: cement: nano anti-shrinkage additive: added water: water reducer = 780kg: 917kg: 305kg: 170kg : 4.6kg of various materials are measured, and the measured crushed raw materials are put into a blade-type high-powered mixer with a speed of 800 rpm. At the same time, the measured cement, water, and various admixtures are added to the mixer. The vacuum switch is turned on, and the vacuum is continuously drawn for 1 minute. The negative pressure is maintained at -0.09Mpa, and then the vibration is turned on. After stirring while vacuuming for 3 minutes, the vacuum is stopped, the vacuum relief valve is opened, but stirring is continued for 0.5 minutes. When the pressure in the cylinder returns to normal, the concrete mixing is completed, the finished concrete is discharged from the mixer, molded and cured, and the corresponding parameters are measured.

[0047] In the multi-source coupling mixing equipment, different raw material test data are shown in Table 1. Examples and performance parameters.

[0048] Table 1

[0049] In order to better illustrate the effects of the above embodiments of the present invention, the following Table 2 shows the performance parameters of concrete prepared by using copper ore fine tailings as raw materials and changing the corresponding process parameters in Comparative Examples 1-8; Comparative Example 1: Concrete was prepared without vacuuming during the mixing process: Process steps: The copper ore fine tailings are first crushed by a hammer crusher to ensure that the granular material will not be broken and decomposed under a compressive strength of 50 MPa; the moisture content, bulk density, dry density, and specific gravity of the crushed copper ore fine tailings are measured, and the dry bulk density and specific gravity of the cement and nano anti-shrinkage additive used are measured; the usage amount of various materials is calculated according to the technology of the present invention (for detailed calculation, refer to the above copper ore fine tailings calculation process); various materials are measured according to the mix ratio of natural copper ore fine tailings: cement: nano anti-shrinkage additive: added water: water reducer = 1526kg: 428kg: 214kg: 100kg: 3.2kg, and the measured crushed raw materials are put into a blade-type high-power mixer with a rotation speed of 800 rpm. At the same time, the measured cement, water, and various admixtures are added to the mixer, and then vibration is turned on. After stirring for 3 minutes, the concrete mixing is completed, and the finished concrete is discharged from the mixer, molded and cured, and the corresponding parameters are measured.

[0050] Comparative Example 2: Concrete was prepared while maintaining a vacuum degree of -0.05 MPa during the stirring process: Process steps: The fine tailings of copper ore were first crushed by a hammer crusher to ensure that the granular materials would not be further crushed and decomposed under a compressive strength of 50 Mpa; the moisture content, bulk density, dry density, and specific gravity of the crushed fine tailings of copper ore were measured, and the dry bulk density and specific gravity of the used cement and nano anti-shrinkage additive were measured; the usage amounts of various materials were calculated according to the technology of the present invention (for the detailed calculation, refer to the above calculation process of the fine tailings of copper ore); various materials were metered according to the mixing ratio of natural state fine tailings of copper ore: cement: nano anti-shrinkage additive: external added water: water reducing agent = 1526 kg: 428 kg: 214 kg: 100 kg: 3.2 kg. The metered crushed raw materials were put into a blade-type powerful mixer with a rotation speed of 800 revolutions per minute. At the same time, the metered cement, water, and various external admixtures were added into the mixer. The vacuum pumping switch was turned on, and vacuum pumping was continuously carried out for 1 minute, with the negative pressure maintained at -0.05 Mpa. Then vibration was started, and stirring was carried out for 3 minutes while pumping vacuum. Then, the vacuum pumping was stopped, the vacuum relief valve was opened, but stirring was continued for 0.5 minute until the pressure in the cylinder returned to normal, thus completing the concrete mixing. The finished concrete was discharged from the mixer, put into molds for curing, and the corresponding parameters were measured.

[0051] Comparative Example 3: Concrete was prepared without vibration during the stirring process: Process steps: The fine tailings of copper ore were first crushed by a hammer crusher to ensure that the granular materials would not be further crushed and decomposed under a compressive strength of 50 Mpa; the moisture content, bulk density, dry density, and specific gravity of the crushed fine tailings of copper ore were measured, and the dry bulk density and specific gravity of the used cement and nano anti-shrinkage additive were measured; the usage amounts of various materials were calculated according to the technology of the present invention (for the detailed calculation, refer to the above calculation process of the fine tailings of copper ore); various materials were metered according to the mixing ratio of natural state fine tailings of copper ore: cement: nano anti-shrinkage additive: external added water: water reducing agent = 1526 kg: 428 kg: 214 kg: 100 kg: 3.2 kg. The metered crushed raw materials were put into a blade-type powerful mixer with a rotation speed of 800 revolutions per minute. At the same time, the metered cement, water, and various external admixtures were added into the mixer. The vacuum pumping switch was turned on, and vacuum pumping was continuously carried out for 1 minute, with the negative pressure maintained at -0.09 Mpa. Stirring was carried out for 3 minutes while pumping vacuum. Then, the vacuum pumping was stopped, the vacuum relief valve was opened, but stirring was continued for 0.5 minute until the pressure in the cylinder returned to normal, thus completing the concrete mixing. The finished concrete was discharged from the mixer, put into molds for curing, and the corresponding parameters were measured.

[0052] Comparative Example 4: Concrete was prepared without adding nano anti-shrinkage additive to the mixing ratio: Process steps: The fine tailings of copper ore are first crushed by a hammer crusher to ensure that the granular materials will not be further crushed and decomposed under a compressive strength of 50 Mpa; measure the moisture content, bulk density, dry density, and specific gravity of the crushed fine tailings of copper ore, and measure the dry bulk density and specific gravity of the used cement and nano anti-shrinkage additive; calculate the usage amounts of various materials according to the technology of the present invention, without calculating the nano anti-shrinkage additive (for detailed calculation, refer to the above calculation process of the fine tailings of copper ore); measure various materials according to the mixing ratio of natural-state fine tailings of copper ore: cement: external added water: water reducer = 1526 kg: 428 kg: 100 kg: 3.2 kg, put the measured crushed raw materials into a vane-type strong mixer with a rotation speed of 800 revolutions per minute, and at the same time add the measured cement, water, and various external admixtures into the mixer, turn on the vacuum pumping switch, continuously pump vacuum for 1 minute, keep the negative pressure at -0.09 Mpa, then turn on the vibration, stir while pumping vacuum for 3 minutes, then stop pumping vacuum, open the vacuum relief valve, but continue to stir for 0.5 minute until the pressure in the cylinder returns to normal, thus completing the concrete mixing, and the finished concrete is discharged from the mixer, put into a mold for curing, and measure the corresponding parameters.

[0053] Comparative Example 5: Prepare concrete at a low rotation speed (100 revolutions per minute) during the mixing process: The fine tailings of copper ore are first crushed by a hammer crusher to ensure that the granular materials will not be further crushed and decomposed under a compressive strength of 50 Mpa; measure the moisture content, bulk density, dry density, and specific gravity of the crushed fine tailings of copper ore, and measure the dry bulk density and specific gravity of the used cement and nano anti-shrinkage additive; calculate the usage amounts of various materials according to the technology of the present invention (for detailed calculation, refer to the above calculation process of the fine tailings of copper ore); measure various materials according to the mixing ratio of natural-state fine tailings of copper ore: cement: nano anti-shrinkage additive: external added water: water reducer = 1526 kg: 428 kg: 214 kg: 100 kg: 3.2 kg, put the measured crushed raw materials into a vane-type strong mixer with a rotation speed of 100 revolutions per minute, and at the same time add the measured cement, water, and various external admixtures into the mixer, turn on the vacuum pumping switch, continuously pump vacuum for 1 minute, keep the negative pressure at -0.09 Mpa, then turn on the vibration, stir while pumping vacuum for 3 minutes, then stop pumping vacuum, open the vacuum relief valve, but continue to stir for 0.5 minute until the pressure in the cylinder returns to normal, thus completing the concrete mixing, and the finished concrete is discharged from the mixer, put into a mold for curing, and measure the corresponding parameters.

[0054] Comparative Example 6: Prepare concrete at a medium rotation speed (400 revolutions per minute) during the mixing process: The fine tailings of copper ore are first crushed by a hammer crusher to ensure that the granular materials will not be further crushed and decomposed under a pressure of 50 Mpa for compressive strength; measure the moisture content, bulk density, dry density, and specific gravity of the crushed fine tailings of copper ore, and measure the dry bulk density and specific gravity of the cement and nano anti-shrinkage additive used; calculate the usage amount of various materials according to the technology of the present invention (for detailed calculation, refer to the above-mentioned calculation process of fine tailings of copper ore); measure various materials according to the mixing ratio of natural state fine tailings of copper ore: cement: nano anti-shrinkage additive: external added water: water reducer = 1526 kg: 428 kg: 214 kg: 100 kg: 3.2 kg, put the measured crushed raw materials into a blade-type powerful mixer with a rotation speed of 400 revolutions per minute, and at the same time add the measured cement, water, and various external admixtures into the mixer, turn on the vacuum pump switch, continuously evacuate for 1 minute, keep the negative pressure at -0.09 Mpa, then turn on the vibration, stir while evacuating for 3 minutes, then stop evacuating, open the vacuum relief valve, but continue to stir for 0.5 minutes until the pressure in the cylinder returns to normal, that is, the concrete mixing is completed, the finished concrete is discharged from the mixer, put into a mold for curing, and the corresponding parameters are measured.

[0055] Comparative Example 7: Prepare concrete at a medium rotation speed (400 revolutions per minute) during the mixing process: The fine tailings of copper ore are first crushed by a hammer crusher to ensure that the granular materials will not be further crushed and decomposed under a pressure of 50 Mpa for compressive strength; measure the moisture content, bulk density, dry density, and specific gravity of the crushed fine tailings of copper ore, and measure the dry bulk density and specific gravity of the cement and nano anti-shrinkage additive used; calculate the usage amount of various materials according to the technology of the present invention (for detailed calculation, refer to the above-mentioned calculation process of fine tailings of copper ore); measure various materials according to the mixing ratio of natural state fine tailings of copper ore: cement: nano anti-shrinkage additive: external added water: water reducer = 1526 kg: 428 kg: 214 kg: 100 kg: 3.2 kg, put the measured crushed raw materials into a conventional horizontal powerful mixer, and at the same time add the measured cement, water, and various external admixtures into the mixer, continuously stir for 3 minutes, then the concrete mixing is completed, the finished concrete is discharged from the mixer, put into a mold for curing, and the corresponding parameters are measured Comparative Example 8: Prepare traditional C40 strength concrete with stones and sand: Select coarse and fine aggregates and sand and gravel materials that meet the requirements of hard texture, good gradation, and qualified mud content and crushing value. Design and calculate the mixing ratio according to the ordinary "Design Code for Mix Proportion of Ordinary Concrete" as cement: stones: sand: water: water reducer = 400 kg: 1100 kg: 700 kg: 170 kg: 2 kg. Measure various materials according to the mixing ratio, put the measured raw materials into a horizontal forced mixer with a rotation speed of 100 revolutions per minute, stir for 3 minutes, then the concrete mixing is completed, the finished concrete is discharged from the mixer, put into a mold for curing, and the corresponding parameters are measured.

[0056] Table 2

[0057] In summary, Examples 1-4 and Comparative Examples 1-8 prove that the multi-source coupling stirring equipment (vacuum -0.09 MPa, vibration, high rotation speed) can significantly improve the compressive strength, flexural strength, reduce the porosity, and improve the impermeability grade compared with the traditional conventional forced stirring equipment; the use of nano-additives can significantly optimize the corresponding compressive strength, flexural strength, porosity, and impermeability grade; compared with the C40 concrete calculated by the traditional unit volume mass method, the corresponding compressive strength, flexural strength, porosity, and impermeability grade are significantly improved; at the same time, the invention technology is applicable to different strongly weathered rocks and tailing waste solids (aluminum oxide tailing solid waste red mud).

[0058] It should be noted that in this article, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0059] The above examples are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various examples of the present invention.

Claims

1. A fine aggregate high-density concrete, characterized in that, The fine aggregate high-density concrete includes solid particle materials, cement, water, and nano anti-shrinkage additives; Among them, the solid particle material, cement, water, and nano anti-shrinkage additive, based on the weight of the solid particle material per unit volume of 1 m 3 , the weight ratio of each component is G A :G c :G js :G a ; Among them, the mix proportion is calculated according to the principle of the unit pore volume compaction method: G A is the weight of the natural solid particle material per unit volume; G c is the weight of the cement filled in the void volume of the solid particle material with weight G A ; G js is the weight of the added water, G js = G wx - G wh , where G wx is the sum of the water weights required for the hydration of G c weight cement and the rheology before the solidification of the concrete, G wh is the natural water content weight of the solid particle material with weight G A ; G a is the weight of the nano anti-shrinkage additive that can be added after removing the volume occupied by the free water in the porosity from the cement pores.

2. The fine aggregate high-density concrete according to claim 1, characterized in that: When the unit volume of the solid particle material is 1 m 3 , its unit pore volume Vp A = 1×(1 - ρ A / d A ), where ρ A is the dry bulk density of the solid particle material, with the unit of kg / m 3 ; d A is the specific gravity of the solid particle material, with the unit of kg / m 3 .

3. The fine aggregate high-density concrete according to claim 1, characterized in that: The weight G of the cement c =Vp A ·ρ c =1×(1 - ρ A / d A )·ρ c , with the unit of kg.

4. The fine aggregate high-density concrete according to claim 1, wherein: The pore volume Vp of the cement c =G c / ρ c ×(1 - ρ c / d c ) = 1×(1 - ρ A / d A )×(1 - ρ c / d c ), where ρ c is the dry bulk density of the cement, and d c is the specific gravity of the cement, with the unit of kg / m 3 , and Vp c is the pore volume of the solid particle material with weight G c , with the unit of m 3 .

5. The fine aggregate high-density concrete according to claim 1, characterized in that: The said G c The weight of water required for the hydration of cement with weight G w = 0.23G c ; and considering the sum of the evaporation loss of water during the concrete preparation and mixing process and the water required for the rheology before curing, G wx = (0.25 - 0.50)Gc, and the unit of all is kg.

6. The fine aggregate high-density concrete according to claim 5, wherein the weight G of the remaining free water in the pores inside the concrete after the fine aggregate high-density concrete is cured wy = (0.02 - 0.27)G c , with the unit of kg; the volume V of the free water in the pores inside the concrete after the cement is cured wy = (0.02 - 0.27)G c / ρ w , where ρ w is the theoretical unit weight of water, taking 1000 kg / m 3 .

7. The fine aggregate high-density concrete according to claim 6, characterized in that: The filling volume Vp of the nano anti-shrinkage additive cy =Vp c -V wy , unit m 3 .

8. The fine aggregate high-density concrete according to claim 7, wherein: The weight G of the nano anti-shrinkage additive material a = ρ a ·Vp cy , with the unit of kg, where ρ a is the bulk density of the nano anti-shrinkage additive material, with the unit of kg / m 3 .

9. The fine aggregate high-density concrete according to claim 1, characterized in that: External added water weight G js = G wx - G wh ; The G wx is G c The sum of the water required for cement hydration and the water required for concrete preparation and mixing; G wh is the weight G A The natural water content weight in solid granular materials.

10. The production process of fine aggregate high-density concrete according to any one of claims 1-9, characterized in that: The production process includes the following steps: Step S1: The solid particle materials are passed through a hammer crusher with a rotation speed greater than 300 r / min and an impact hammer force of 50 - 500 KN to ensure that the particle materials will not be further broken down under a compressive strength of 50 - 200 Mpa. Step S2: For the crushed solid particle materials, tests are conducted on the moisture content, bulk density, dry density, and specific gravity, and the dry bulk density and specific gravity of the used cement and nano anti-shrinkage additives are also tested. Step S3: Mix ratio calculation is carried out according to the principle of the unit pore volume densification method, and the concrete mix ratio is determined through sample tests for verification. Step S4: Calculate the usage amounts of each material according to the mix ratio. The metered crushed raw materials enter a multi-source coupling powerful mixer of vane type, anchor type, or turbine type with a rotation speed of 100 - 800 revolutions per minute under ultrasonic, vibration, and negative pressure environments. Step S5: Add the metered cement, water, and admixtures to the mixer. First, turn on the vacuum pump switch, keep the negative pressure at -0.02 - -0.09 Mpa, and continuously evacuate for 0.5 - 1 minute. Then turn on the vibration and high-speed stirring, and keep vibrating, stirring, and evacuating simultaneously for 3 - 4 minutes. Then stop evacuating, open the vacuum relief valve, but continue stirring for 0.5 - 1 minute until the pressure in the cylinder returns to normal, thus completing the concrete mixing. The finished concrete is discharged from the mixer.

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