CN110937865A

CN110937865A - C30 recycled aggregate concrete and preparation method thereof

Info

Publication number: CN110937865A
Application number: CN201911170397.8A
Authority: CN
Inventors: 任军卫; 陈永杰; 牛光杰; 赵明廷; 任君峰
Original assignee: Qingdao Huixin Concrete Co Ltd
Current assignee: Qingdao Huixin Concrete Co Ltd
Priority date: 2019-11-26
Filing date: 2019-11-26
Publication date: 2020-03-31

Abstract

The invention discloses C30 recycled aggregate concrete and a preparation method thereof. The C30 recycled aggregate concrete comprises the following components: cement, mineral powder, fly ash, sand, stones, water, an additive and recycled aggregate; the recycled aggregate comprises activated iron tailings and waste slurry water in a mass ratio of 1: 0.3-0.6; the preparation method of the activated iron tailings comprises the following steps: (1) drying the iron tailing sand and the red mud at the temperature of 100-110 ℃ for 2-2.5 h; (2) adding sodium silicate and diatomite into the iron tailing sand and the red mud prepared in the step (1), wet-grinding for 10-20min, drying after wet-grinding, calcining for 1-2h at the temperature of 600-700 ℃, dry-grinding for 10-15min, and sieving by a 200-mesh sieve to prepare the activated iron tailing. The C30 recycled aggregate concrete has the advantages of high compressive strength, reduction of environmental pollution caused by iron tailings and concrete waste slurry, resource saving and environmental protection.

Description

C30 recycled aggregate concrete and preparation method thereof

Technical Field

The invention relates to the technical field of building materials, in particular to C30 recycled aggregate concrete and a preparation method thereof.

Background

Concrete is one of the most important civil engineering materials in the present generation, has the characteristics of rich raw materials, low price, simple production process and the like, so the dosage of the concrete is increased, and simultaneously, the concrete also has the characteristics of high compressive strength, good durability, wide strength grade range and the like, so the concrete is also an important material in the fields of shipbuilding industry, mechanical industry, ocean development, geothermal engineering and the like.

The tailings are the wastes after mineral separation and are the main components of industrial solid wastes, a large amount of tailing sand not only occupies the land, but also generates dust to pollute the environment, and at present, the comprehensive utilization rate of the tailings in China is only 7%, so the comprehensive recycling problem of the tailings has been widely concerned by the whole society.

In the prior art, Chinese patent application with application number CN201410193087.9 discloses a high-strength concrete with high iron tailing sand content and a preparation method thereof, wherein the high-strength concrete is prepared from the following raw materials: the mixed sand comprises iron tailing sand and natural river sand, wherein the iron tailing sand replaces the natural river sand by weight percent, namely the iron tailing sand accounts for 60-70 percent of the total weight of the mixed sand, and the fineness modulus of the iron tailing sand is 1.9-2.6.

A large amount of iron tailings are doped into the existing concrete, and because the iron tailings have high water absorption rate, rough surface and high porosity, when the doping amount is high, the iron tailings easily absorb more free water in the concrete, so that the slump loss of the concrete is high, the workability is poor, the concrete is easy to disperse, and the strength is low.

When the commercial concrete is produced in the concrete mixing plant, a large amount of waste slurry water can be produced, the waste slurry water mainly comes from cleaning discharge materials of concrete equipment such as a mixer truck and a pump truck, and if the residual materials in the slurry water are separated, the waste slurry water is directly precipitated into hard blocks to be treated as garbage, so that not only is great waste caused, but also great pollution is caused to the environment.

Therefore, the problem to be solved is to develop a method for reasonably recycling the iron tailings and the high-concentration concrete grout and preparing the concrete with the strength grade reaching above C30.

Disclosure of Invention

Aiming at the defects in the prior art, the first purpose of the invention is to provide the C30 recycled aggregate concrete which has the advantages of high compressive strength, reasonable utilization of iron tailings and concrete grout, reduction of the environmental pollution caused by the iron tailings and the concrete grout, increase of the utilization rate of the iron tailings and the high-concentration concrete grout, resource saving and environmental protection.

The second purpose of the invention is to provide a preparation method of C30 recycled aggregate concrete, which has the advantages of easily regulated and controlled process and simple and convenient preparation.

In order to achieve the first object, the invention provides the following technical scheme: the C30 recycled aggregate concrete comprises the following components in parts by weight: 230-270 parts of cement, 80-100 parts of mineral powder, 50-70 parts of fly ash, 770-810 parts of sand, 925-965 parts of stones, 155-195 parts of water, 8.2-10.2 parts of additive and 30-60 parts of recycled aggregate;

the recycled aggregate comprises activated iron tailings and waste slurry water in a mass ratio of 1: 0.3-0.6;

the preparation method of the activated iron tailings comprises the following steps: (1) drying the iron tailing sand and the red mud at the temperature of 100-110 ℃ for 2-2.5 h; (2) adding sodium silicate and diatomite into the iron tailing sand and the red mud prepared in the step (1), wet-grinding for 10-20min at the concentration of 67-70%, drying at the temperature of 100-120 ℃ after wet-grinding, calcining for 1-2h at the temperature of 600-700 ℃, dry-grinding for 10-15min, and sieving by a 200-mesh sieve to prepare the activated iron tailing, wherein the mass ratio of the iron tailing sand to the red mud is 2:0.9-1.1, and the mass ratio of the iron tailing sand to the sodium silicate to the diatomite is 1 (0.3-0.5) to (0.5-0.8).

By adopting the technical scheme, the activated iron tailings and the waste slurry water are used as recycled aggregates to prepare concrete, and the red mud, the sodium silicate and the diatomite are used for activating the iron tailings, so that the waste slurry water and the iron tailings are reasonably utilized, the pollution of the iron tailings and the waste slurry water to the environment is reduced, the resources are saved, and the environment is protected; because the red mud and the iron tailings belong to industrial wastes and contain 8-9% of structural water, the structural water makes the red mud and the iron tailings in a metastable state when being calcined and removed, and can also generate solid-phase reaction at high temperature to generate a high-activity metastable substance, thereby improving the activity of the materials, after the red mud and the iron tailings are mixed with the sodium silicate and the diatomite for wet grinding, the red mud generates certain alteration effect on minerals in the mixture when being heated and dehydrated, so that the distortion degree of the mineral structure is increased, thereby improving the activity of the whole material system, and reducing the particles by using wet grinding operation, the contact of the materials is more compact, the interaction between the materials in calcination is favorably strengthened, the activity of the mixture of the red mud and the iron tailings is further improved, and the slump loss of the concrete can be reduced by the red mud and the iron tailings which lose free water, so that the workability and the compressive strength of the concrete are improved.

Further, the components in parts by weight are as follows: 24-260 parts of cement, 85-95 parts of mineral powder, 55-65 parts of fly ash, 780-sand, 935-gravel, 165-185 parts of water, 8.7-9.7 parts of additive and 40-50 parts of recycled aggregate;

the recycled aggregate comprises activated iron tailings and waste slurry water in a mass ratio of 1: 0.4.

By adopting the technical scheme, the dosage of each raw material in the concrete is more accurate and optimized, so that the prepared concrete has more excellent compressive strength.

Further, when the concentration of the waste slurry exceeds 8%, the following treatment is required: (1) passing the waste slurry through a sand-stone separation device, wherein the aperture of a screen in the sand-stone separation device is 0.15-0.2mm, adding clear water with the total amount of 2-4 times of that of the separated waste slurry, and uniformly mixing;

(2) mixing acrylic acid, ethylene glycol dimethacrylate and acrylamide to prepare a mixed solution 1, mixing sodium hydrosulfite and 3-mercaptopropionic acid to prepare a mixed solution 2, mixing prenyl alcohol polyoxyethylene ether, water, acrylic acid and hydrogen peroxide, adding the mixed solution 1 and the mixed solution 2, stirring for 1-2 hours at 80-100 ℃ to prepare a mixed solution 3, wherein the raw materials comprise the following components in parts by weight: 3.5-4 parts of acrylic acid, 2-2.5 parts of ethylene glycol dimethacrylate, 1-1.2 parts of acrylamide, 1-1.2 parts of sodium hydrosulfite, 0.3-0.5 part of 3-mercaptopropionic acid, 1-1.2 parts of prenyl polyoxyethylene ether, 3-4 parts of hydrogen peroxide and 2-4 parts of water;

(3) adjusting the pH of the mixed solution 3 to 6-7 by using a sodium hydroxide solution with the concentration of 32%, adding the obtained mixed solution 3 into the waste slurry prepared in the step (1), adding eleostearic acid, 2BaO & SiO2 and syneresis microbeads, and uniformly mixing to finish treatment, wherein the raw materials comprise the following components in parts by weight: 1.2-1.5 parts of mixed solution 3, 4-6 parts of waste slurry water, 1.8-2.2 parts of eleostearic acid and 1.4-1.8 parts of 2BaO SiO₂And 2.5-3 parts of consubstantial microbeads.

By adopting the technical scheme, when the concentration of the concrete waste slurry water is higher than 8%, the fine aggregate contained in the concrete waste slurry water is increased, so that the adsorption force of the concrete waste slurry water on an additive is enhanced, partial additive is failed, the sand rate is obviously increased, the concrete is sticky, the water consumption is increased, the strength of the prepared concrete is unqualified, the slump loss is too high, the performance of the concrete cannot be seriously influenced by construction after construction on a construction site, the concrete waste slurry water contains clay or sludge particles, soluble inorganic salt, additive ions and the like brought by fine cement particles and the like, wherein harmful ions influencing the performance of the concrete are mainly sodium ions, potassium ions, sulfur ions and sulfate ions, the durability of the concrete is influenced by the sulfate ions, and the sulfide can cause brittle fracture of reinforcing steel bars; the method comprises the following steps of firstly filtering to remove aggregates with larger particles, reducing the adsorption force of the aggregates, effectively reducing the viscosity of waste slurry water by introducing a shorter polyoxyethylene side chain and cationic monomer acrylamide into an isopentenol polyoxyethylene ether chain, and enabling the concrete to have better slump retentivity by introducing ethylene glycol dimethacrylate, wherein the ethylene glycol dimethacrylate has a synergistic effect with a synthetic microbead with a ball lubricating effect, so that the interaction force of fine aggregate quality inspection in the waste slurry water can be reduced, free water is released, the concrete particles are filled with the free water, the bulk density is increased, the viscosity is further reduced, and the concrete compactness is increased; meanwhile, the added eleostearic acid has the functions of water resistance, acid and alkali resistance, corrosion resistance and rust resistance, and can delay 2BaO SiO₂The hydration speed of the cement can avoid the reaction of gypsum and Ba0 to influence the normal setting of the cement, and Ba0 reacts with sulfate ions permeating into the concrete to generate an almost insoluble mixture, namely sulfurThe acid barium enables the structure of the cement to be more compact, and simultaneously avoids the reaction of generating ettringite, thereby improving the sulfate corrosion resistance of the concrete and enhancing the wear resistance of the concrete.

Further, the admixture is prepared by the following method:

(1) crushing and grinding the coal gangue material, sieving the crushed and ground coal gangue material by a 120-mesh square-hole sieve to ensure that the balance of the sieve is 3-5%, and calcining the crushed and ground coal gangue material at the constant temperature of 500-700 ℃ for 1.5-2h to prepare activated coal gangue powder;

(2) the activated coal gangue powder is uniformly mixed with triethanolamine, urea, polyacrylamide and a water reducing agent to prepare an additive, wherein the activated coal gangue powder comprises 3 to 5 parts by weight of triethanolamine, 0.4 to 0.6 part by weight of urea, 0.5 to 0.7 part by weight of polyacrylamide and 0.8 to 1.4 parts by weight of water reducing agent.

By adopting the technical scheme, after the coal gangue is calcined at the temperature of 500-700 ℃, part of structural water in the kaolin and mica minerals in the coal gangue is removed, amorphous silicon dioxide is generated, so that the content of silicon dioxide in the calcined coal gangue is relatively increased, the phase composition and microstructure of the coal gangue can be obviously improved by the silicon dioxide and the alumina with the function of activating blood, the activity of the coal gangue is improved, the silicon dioxide can react with calcium hydroxide to generate calcium silicate gel, the compressive strength of concrete is improved, and the performances of frost resistance, early strength and the like of the concrete can be improved by triethanolamine, urea and the like.

Further, the water reducing agent is one or a composition of two of a polycarboxylic acid high-efficiency water reducing agent and a naphthalene sulfonate formal series high-efficiency water reducing agent.

By adopting the technical scheme, the high-efficiency water reducing agent has certain promotion effect on the hydration of cement, and the naphthalene sulfonate formal series high-efficiency water reducing agent can be adsorbed on the surface of particles, so that the mutual repulsion effect among the particles is increased, the cement particles are promoted to be dispersed, water wrapped by the flocculating constituents is released, the purpose of reducing water is achieved, the viscosity of cement paste is reduced, and the fluidity is improved.

Furthermore, the raw materials also comprise recycled building micro powder, the mass ratio of the recycled building micro powder to the cement is 1:0.3-0.5, and the recycled building micro powder comprises the building garbage micro powder, the dihydrate gypsum and the cement clinker in the mass ratio of (1-3) - (0.2-0.4) - (0.6-0.8).

By adopting the technical scheme, the hydration of a proper amount of gypsum clinker is promoted, the hardening strength, the wear resistance and the water resistance are improved after the concrete is condensed, and the concrete has the advantages of large volume density, small apparent porosity, high strength and good wear resistance.

Further, the preparation method of the regenerated building micro powder comprises the following steps: crushing the construction waste into particles of 30-40mm, calcining for 1-2h at the temperature of 400-.

Furthermore, the sand is river sand in a zone II, the fineness modulus is 3.0-2.3, and the mud content is 2.3-2.5%; the particle size of the stones is 5-31.5mm, the continuous gradation is realized, and the mud content is 0.3-0.5%.

By adopting the technical scheme, the river sand has high hardness and good wear resistance, and the content of clay and other harmful impurities is low, so that the scouring resistance of the concrete is good, the fineness modulus is proper, the concrete has better workability, the construction workability is good, the stirring is easy, the concrete can be filled in the pores among the coarse aggregates, the compactness and the strength of the concrete are improved, the porosity in the concrete is reduced, the segregation and bleeding of the concrete are reduced, and the strength of the concrete is improved; the mud content in the stones is appropriate, the strength of the concrete can be effectively improved, the situation that the particles are large is avoided, the pores among the aggregates are large, the strength of the concrete is low, reasonable grading is formed among the aggregates, the river sand, the fly ash and the mineral powder, the compactness of the concrete can be improved, and the strength and the wear resistance of the concrete are improved.

Further, the fly ash is F-class II fly ash, the fineness (the screen residue of a 45-micron square-hole screen) is less than or equal to 12 percent, the water demand ratio is 95-98 percent, and the ignition loss is less than or equal to 4.5 percent; the mineral powder is S95 grade mineral powder, the specific surface area of the mineral powder is 400-450m2/kg, the activity index in 28 days is 95%, and the fluidity ratio is 99%.

By adopting the technical scheme, the active ingredients of the fly ash are silicon dioxide and aluminum oxide, and the fly ash can generate a stable cementing material after being mixed with cement and water, so that the concrete has higher strength, meanwhile, more than 70% of particles in the fly ash are amorphous spherical glass bodies, and mainly play a role of a ball bearing, play a lubricating role in a concrete mixture, improve the workability of the concrete mixture, and the fly ash and broken stones and the like form reasonable grading, so that the fly ash and the broken stones are mutually filled, the compactness of the concrete can be effectively increased, and the compressive strength of the concrete is further improved; the mineral powder mineral admixture has a plurality of comprehensive effects such as an active effect, an interface effect, a micro-filling effect and a water reducing effect, and not only can improve the rheological property, reduce the hydration heat, reduce the slump loss, reduce the segregation and the bleeding, but also can improve the pore structure and the mechanical property of a concrete structure, and improve the later strength and the durability.

In order to achieve the second object, the invention provides the following technical scheme: a preparation method of C30 recycled aggregate concrete comprises the following steps:

s1, fully and uniformly mixing cement, fly ash, sand, stones and mineral powder to prepare a premix;

s2, uniformly mixing the recycled aggregate and the recycled building micro powder, adding the water fully mixed with the additive into the mixture of the recycled aggregate and the recycled building micro powder, uniformly stirring, adding the premix, and uniformly mixing to obtain the C30 recycled aggregate concrete.

In conclusion, the invention has the following beneficial effects:

firstly, because the invention adopts the concrete waste slurry and the activated iron tailings as the recycled aggregate to be mixed into the concrete, because the invention is mixed with the red mud for calcination and then mixed with the sodium silicate and the diatomite for wet grinding, the iron tailings and the red mud lose the internal free water, the internal minerals are subjected to alteration action, the activity is improved, the waste slurry water is recycled, the waste can be utilized, the cost is saved, the invention is beneficial to promoting the environmental protection and the green protection of the commercial concrete production, and the invention has better technical, economic and environmental benefits.

Second, the preferred use of prenol poly(s) in the present inventionTreating waste slurry with concentration higher than 8% with oxyethylene ether and acrylamide, and mixing with eleostearic acid, 2BaO SiO₂And the syngenic microbeads are fine in particles, so that the syngenic microbeads can be adsorbed on the surface of fine aggregate, the interaction force among the particles is reduced, free water is released, the ball lubrication effect is achieved, and waste slurry water with larger concentration of concrete is doped into the concrete by matching with ethylene glycol dimethacrylate and the like, so that the viscosity of the concrete is reduced, the slump loss is reduced, and the workability is improved.

Thirdly, in the invention, eleostearic acid and 2BaO SiO are preferably mixed into the waste slurry with the concentration of more than 8 percent₂The concrete anti-sulfate radical and chloride ion corrosion capacity can be enhanced, the density of the concrete is increased, the condition that the durability of the concrete is influenced by sulfate radicals in waste slurry with high concentration and the reinforcing steel bar brittle failure is caused by sulfides is prevented.

Fourthly, the invention preferably adds the recycled building micro powder prepared by mixing the building garbage micro powder, the dihydrate gypsum and the cement clinker into the concrete, the hydration of a proper amount of the gypsum clinker is promoted, after the concrete is condensed, the hardening strength, the wear resistance and the water resistance are improved, and the concrete has large volume density, small apparent porosity and large strength.

Detailed Description

The present invention will be described in further detail with reference to examples.

Preparation examples 1 to 3 of activated iron tailings

Preparation example 1: (1) drying the iron tailing sand and the red mud for 2.5 hours at the temperature of 100 ℃, wherein the component analysis of the iron tailing sand and the red mud is shown in the table 1; (2) adding sodium silicate and diatomite into the iron tailing sand and the red mud prepared in the step (1), wet-grinding for 20min at a concentration of 67%, drying at 100 ℃ after wet-grinding, calcining for 2h at 600 ℃, dry-grinding for 10min, and sieving by a 200-mesh sieve to prepare the activated iron tailing, wherein the mass ratio of the iron tailing sand to the red mud is 2:0.9, and the mass ratio of the iron tailing sand to the sodium silicate to the diatomite is 1:0.3: 0.5.

TABLE 1 main chemical composition of iron tailings sand and red mud in preparation examples 1-3

Composition (I)	Fe₂O₃	SiO₂	CaO	MgO	Al₂O₃	Na₂O	K₂O
								Iron tailings sand w/%)	13.82	63.07	8.18	0.23	5.6	/	/
W/percent of red mud	15.8	22.6	42.7	1.4	12.5	4.1	0.8

Preparation example 2: (1) drying the iron tailing sand and the red mud at 105 ℃ for 2.3h, wherein the component analysis of the iron tailing sand and the red mud is shown in Table 1; (2) adding sodium silicate and diatomite into the iron tailing sand and the red mud prepared in the step (1), wet-grinding for 15min at a concentration of 68%, drying at 110 ℃ after wet-grinding, calcining for 1.5h at 650 ℃, dry-grinding for 15min, and sieving with a 200-mesh sieve to prepare the activated iron tailing, wherein the mass ratio of the iron tailing sand to the red mud is 2:1, and the mass ratio of the iron tailing sand to the sodium silicate to the diatomite is 1:0.4: 0.6.

Preparation example 3: (1) drying the iron tailing sand and the red mud for 2 hours at 110 ℃, wherein the component analysis of the iron tailing sand and the red mud is shown in table 1; (2) adding sodium silicate and diatomite into the iron tailing sand and the red mud prepared in the step (1), wet-grinding for 10min at the concentration of 70%, drying at 120 ℃ after wet-grinding, calcining for 1h at 700 ℃, dry-grinding for 20min, and sieving by a 200-mesh sieve to prepare the activated iron tailing, wherein the mass ratio of the iron tailing sand to the red mud is 2:1.1, and the mass ratio of the iron tailing sand to the sodium silicate to the diatomite is 1:0.5: 0.8.

Preparation examples 4 to 6 of admixtures

Preparation example 4: (1) crushing and grinding the coal gangue material, sieving the crushed coal gangue material by a 120-mesh square-hole sieve to ensure that the balance of the sieve is 3 percent, and calcining the crushed coal gangue material at the constant temperature of 500 ℃ for 2 hours to prepare activated coal gangue powder, wherein the chemical components of the coal gangue material are shown in a table 2;

(2) uniformly mixing activated coal gangue powder with triethanolamine, urea, polyacrylamide and a water reducing agent to prepare an additive, wherein the raw materials comprise the following components in parts by weight: 3kg of activated coal gangue powder, 0.4kg of triethanolamine, 0.5kg of urea, 1.1kg of polyacrylamide and 0.8kg of water reducing agent, wherein the water reducing agent is a polycarboxylic acid high-efficiency water reducing agent.

TABLE 2 chemical composition of coal gangue Material in additives in preparation examples 4-6

Composition (I)	SiO₂	Al₂O₃	CaO	MgO	Na₂O	K₂O	Fe₂O₃	SO₃	Loss
										w/％	65.66	20.73	0.13	0.21	0.09	0.71	0.64	0.48	9.86

Preparation example 5: (1) crushing and grinding the coal gangue material, sieving the crushed coal gangue material by a 120-mesh square-hole sieve to ensure that the balance of the sieve is 4 percent, and calcining the crushed coal gangue material at the constant temperature of 600 ℃ for 1.8 hours to prepare activated coal gangue material, wherein the chemical components of the coal gangue material are shown in Table 2;

(2) uniformly mixing activated coal gangue powder with triethanolamine, urea, polyacrylamide and a water reducing agent to prepare an additive, wherein the raw materials comprise the following components in parts by weight: 4kg of activated coal gangue powder, 0.5kg of triethanolamine, 0.6kg of urea, 1.3kg of polyacrylamide and 1.1kg of water reducing agent, wherein the water reducing agent is naphthalene sulfonate formal series high-efficiency water reducing agent.

Preparation example 6: (1) crushing and grinding the coal gangue material, sieving the crushed coal gangue material by a 120-mesh square-hole sieve to ensure that the balance of the sieve is 5 percent, and calcining the crushed coal gangue material at the constant temperature of 700 ℃ for 1.5 hours to prepare activated coal gangue material, wherein the chemical components of the coal gangue material are shown in Table 2;

(2) uniformly mixing activated coal gangue powder with triethanolamine, urea, polyacrylamide and a water reducing agent to prepare an additive, wherein the raw materials comprise the following components in parts by weight: 5kg of activated coal gangue powder, 0.6kg of triethanolamine, 0.7kg of urea, 1.5kg of polyacrylamide and 1.4kg of water reducing agent, wherein the water reducing agent is a polycarboxylic acid high-efficiency water reducing agent and a naphthalene sulfonate formal series high-efficiency water reducing agent with the mass ratio of 1: 2.

Preparation examples 7 to 9 of recycled building micropowder

Preparation example 7: crushing the construction waste into particles of 30mm, calcining for 1h at 400 ℃, heating to 800 ℃, preserving heat for 2.5h, cooling to room temperature, mixing with dihydrate gypsum and cement clinker, grinding to obtain regenerated construction micro powder with the average particle size of 40 mu m, wherein the mass ratio of the construction waste micro powder to the dihydrate gypsum to the cement clinker is 1:0.2:0.6, and the chemical components of the dihydrate gypsum and the cement clinker are shown in Table 3.

TABLE 3 chemical compositions of dihydrate Gypsum and Cement Clinker in the recycled building micropowder of preparation examples 7-9

Preparation example 8: crushing the construction waste into particles of 35mm, calcining for 1.5h at 500 ℃, heating to 850 ℃, keeping the temperature for 2.3h, cooling to room temperature, mixing with the dihydrate gypsum and the cement clinker, and grinding to obtain the regenerated construction micro powder with the average particle size of 50 mu m, wherein the mass ratio of the construction waste micro powder to the dihydrate gypsum to the cement clinker is 2:0.3:0.7, and the chemical components of the dihydrate gypsum and the cement clinker are shown in Table 3.

Preparation example 9: crushing the construction waste into particles of 40mm, calcining for 1h at 600 ℃, heating to 900 ℃, preserving heat for 2h, cooling to room temperature, mixing with dihydrate gypsum and cement clinker, and grinding to obtain the regenerated construction micro powder with the average particle size of 60 mu m, wherein the mass ratio of the construction waste micro powder to the dihydrate gypsum to the cement clinker is 3:0.4:0.8, and the chemical components of the dihydrate gypsum and the cement clinker are shown in Table 3.

Examples

In the following examples, the naphthalene sulfonate formal water reducer is selected from the naphthalene sulfonate formal water reducer sold by Didization technology Limited, Huainan, with model number UNF-2, the polycarboxylate water reducer is selected from the polycarboxylate water reducer sold by Shajian chemical products Limited, Zhengzhou, with model number sy-1902, and the eleostearic acid is selected from the eleostearic acid sold by Rifinde oil deep processing Limited, Anhui, with model number T155.

Example 1: the raw material formulation of the C30 recycled aggregate concrete is shown in Table 4, and the preparation method of the C30 recycled aggregate concrete comprises the following steps:

s1, mixing the mixture with 230kg/m³50kg/m of cement³Flyash 770kg/m³Sand, 965kg/m³Pebbles and 100kg/m³Fully and uniformly mixing the mineral powder to prepare a premix;

wherein the cement is portland cement, the fly ash is class F class II fly ash, the fineness (the screen allowance of a 45-micron square-hole screen) is less than or equal to 12 percent, the water demand ratio is 95 percent, the loss on ignition is less than or equal to 4.5 percent, the sand is river sand in a II area, the fineness modulus is 3.0, the mud content is 2.3 percent, the particle size of the stone is 5-31.5mm continuous gradation, the mud content is 0.3 percent, the mineral powder is class S95 mineral powder, the specific surface area of the mineral powder is 400m²Kg, 28 days activity index 95%, fluidity ratio 99%;

s2, mixing the powder with 8.2kg/m³195kg/m of fully mixed admixture³Adding water to 30kg/m³Adding a premix into the recycled aggregate after uniformly stirring, and uniformly mixing to prepare C30 recycled aggregate concrete, wherein the admixture is prepared by preparation example 4, the recycled aggregate comprises activated iron tailings and waste slurry water in a mass ratio of 1:0.3, the activated iron tailings are prepared by preparation example 1, the concentration of the waste slurry water is 2%,the water quality analysis results of the waste slurry are shown in Table 5, and meet the water consumption requirements of reinforced concrete in JGJ63-2006 Water for concrete Standard.

TABLE 4 raw material composition of C30 recycled aggregate concrete in examples 1-5

Example 2: the raw material formulation of the C30 recycled aggregate concrete is shown in Table 4, and the preparation method of the C30 recycled aggregate concrete comprises the following steps:

s1, mixing 240kg/m³55kg/m of cement³780kg/m of fly ash³Sand, 955kg/m³Stone and 95kg/m³Fully and uniformly mixing the mineral powder to prepare a premix;

wherein the cement is portland cement, the fly ash is class F class II fly ash, the fineness (the screen allowance of a 45-micron square-hole screen) is less than or equal to 12 percent, the water demand ratio is 97 percent, the loss on ignition is less than or equal to 4.5 percent, the sand is river sand in a II area, the fineness modulus is 2.7, the mud content is 2.4 percent, the particle size of the stone is 5-31.5mm continuous gradation, the mud content is 0.4 percent, the mineral powder is class S95 mineral powder, the specific surface area of the mineral powder is 430m²Kg, 28 days activity index 95%, fluidity ratio 99%;

s2, mixing the powder with 8.7kg/m³185kg/m after the admixture is fully mixed³Adding water to 40kg/m³The recycled aggregate is uniformly stirred, and then the premix is added and uniformly mixed to prepare C30 recycled aggregate concrete, the admixture is prepared from preparation example 5, the recycled aggregate comprises activated iron tailings and waste slurry water in a mass ratio of 1:0.4, the activated iron tailings are prepared from preparation example 2, the concentration of the waste slurry water is 4%, and the water quality analysis result of the waste slurry water is shown in Table 5 and meets the water requirement of reinforced concrete in JGJ63-2006 Water for concrete Standard.

Example 3: the raw material formulation of the C30 recycled aggregate concrete is shown in Table 4, and the preparation method of the C30 recycled aggregate concrete comprises the following steps:

s1, mixing 250kg/m³60kg/m of cement³Fly ash, 790kg/m³Sand、945kg/m³Pebbles and 90kg/m³Fully and uniformly mixing the mineral powder to prepare a premix;

wherein the cement is portland cement, the fly ash is class F class II fly ash, the fineness (the screen allowance of a 45-micron square-hole screen) is less than or equal to 12 percent, the water demand ratio is 98 percent, the loss on ignition is less than or equal to 4.5 percent, the sand is river sand in a II area, the fineness modulus is 2.3, the mud content is 2.5 percent, the particle size of the stone is 5-31.5mm continuous gradation, the mud content is 0.5 percent, the mineral powder is class S95 mineral powder, the specific surface area of the mineral powder is 450m²Kg, 28 days activity index 95%, fluidity ratio 99%;

s2, mixing with 9.2kg/m³175kg/m after fully mixing the admixture³Adding water to the mixture to a concentration of 45kg/m³The recycled aggregate is uniformly stirred, and then the premix is added and uniformly mixed to prepare C30 recycled aggregate concrete, the admixture is prepared by the preparation example 6, the recycled aggregate comprises activated iron tailings and waste slurry water in a mass ratio of 1:0.6, the activated iron tailings are prepared by the preparation example 3, the concentration of the waste slurry water is 6%, and the water quality analysis result of the waste slurry water is shown in Table 6 and meets the water requirement of reinforced concrete in JGJ63-2006 Water for concrete Standard.

Example 4: the recycled aggregate concrete C30 is different from the recycled aggregate concrete in example 1 in that the raw material formula is shown in Table 4, the concentration of the waste slurry is 8%, and the water quality analysis result of the waste slurry is shown in Table 5 and meets the water requirement of reinforced concrete in JGJ63-2006 Water for concrete Standard.

TABLE 5 Water quality analysis results of waste muddy water in examples 1-4

Detecting items	Standard requirements	Example 1	Example 2	Example 3	Example 4
						Water concentration of waste pulp/%)	/	2	4	6	8
pH value	≥4.5	7.7	8.9	10.1	11.7
						Content of insoluble matter	≤2000	359	5320	10540	15630
Soluble content	≤5000	1175	1156	1745	2634
						Chloride content	≤1000	134	152	163	173
Sulfate content	≤2000	83	132	166	238
						Alkali content	≤1500	246	1136	1562	2267

Example 5: a C30 recycled aggregate concrete is different from the concrete in example 1 in that the concentration of the waste slurry is 10%, and the waste slurry is treated by the following steps: (1) enabling the waste slurry water to pass through a sand-stone separation device, wherein the aperture of a screen in the sand-stone separation device is 0.15mm, adding clear water with the total amount being 2 times of that of the separated waste slurry water, and uniformly mixing;

(2) mixing 3.5kg of acrylic acid, 2kg of ethylene glycol dimethacrylate and acrylamide to prepare a mixed solution 1, mixing 1kg of sodium hydrosulfite and 0.3kg of 3-mercaptopropionic acid to prepare a mixed solution 2, mixing 1kg of prenyl alcohol polyoxyethylene ether, 2kg of water, 3.5kg of acrylic acid and 3kg of hydrogen peroxide, adding the mixed solution 1 and the mixed solution 2, and stirring for 2 hours at 80 ℃ to prepare a mixed solution 3; (3) after the pH of the mixed solution 3 was adjusted to 6 with a 32% sodium hydroxide solution, 1.2kg of the mixed solution 3 was added to 4kg of the waste slurry prepared in step (1), 1.8kg of eleostearic acid and 1.4kg of 2 BaO. SiO₂Mixing with 2.5kg of syngenic microbeads with the particle size of 0.1 μm, and analyzing the waste slurry to obtain the composition JGJ63 shown in Table 6-water requirement for reinforced concrete in 2006 "water standards for concrete".

TABLE 6 analysis results of water components of the treated waster slurries of examples 5 to 7

Detecting items	Standard requirements	Example 5	Example 6	Example 7
					Water concentration of waste pulp/%)	/	10	12	14
pH value	≥4.5	10.2	10.5	10.6
					Content of insoluble matter	≤2000	435	5614	8567
Soluble content	≤5000	1457	1683	1858
					Chloride content	≤1000	152	168	179
Sulfate content	≤2000	89	126	148
					Alkali content	≤1500	256	1345	1782

Example 6: a C30 recycled aggregate concrete is different from the concrete in example 1 in that the concentration of the waste slurry is 12%, and the waste slurry is treated by the following steps: (1) enabling the waste slurry water to pass through a sand-stone separation device, wherein the aperture of a screen in the sand-stone separation device is 0.2mm, adding clear water with the total amount being 3 times of that of the separated waste slurry water, and uniformly mixing;

(2) mixing 3.8kg of acrylic acid, 2.3kg of ethylene glycol dimethacrylate and acrylamide to prepare a mixed solution 1, mixing 1.1kg of sodium hydrosulfite and 0.4kg of 3-mercaptopropionic acid to prepare a mixed solution 2, mixing 1.1kg of prenyl polyoxyethylene ether, 3kg of water, 3.8kg of acrylic acid and 3.5kg of hydrogen peroxide, adding the mixed solution 1 and the mixed solution 2, and stirring at 90 ℃ for 1.5 hours to prepare a mixed solution 3;

(3) using 32% strength sodium hydroxide solutionAfter the pH of the mixed solution 3 was adjusted to 6.5, 1.4kg of the mixed solution 3 was added to 5g of the waste slurry prepared in step (1), 2kg of eleostearic acid and 1.6kg of 2 BaO. SiO₂And 2.8kg of synthetic microbeads, wherein the particle size of the synthetic microbeads is 0.3 mu m, and the analysis result of the components of the treated waste slurry is shown in Table 6 and meets the water requirement of reinforced concrete in JGJ63-2006 Water Standard for concrete.

Example 7: a C30 recycled aggregate concrete is different from the concrete in example 1 in that the concentration of the waste slurry is 14%, and the waste slurry is treated by the following steps: (1) enabling the waste slurry water to pass through a sand-stone separation device, wherein the aperture of a screen in the sand-stone separation device is 0.2mm, adding clear water of which the total amount is 4 times of that of the separated waste slurry water, and uniformly mixing;

(2) mixing 4kg of acrylic acid, 2.5kg of ethylene glycol dimethacrylate and acrylamide to prepare a mixed solution 1, mixing 1.2kg of sodium hydrosulfite and 0.5kg of 3-mercaptopropionic acid to prepare a mixed solution 2, mixing 1.2kg of prenyl alcohol polyoxyethylene ether, 4kg of water, 4kg of acrylic acid and 4kg of hydrogen peroxide, adding the mixed solution 1 and the mixed solution 2, and stirring for 1 hour at 100 ℃ to prepare a mixed solution 3;

(3) after the pH of the mixed solution 3 was adjusted to 7 with a 32% sodium hydroxide solution, 1.5kg of the mixed solution 3 was added to 6g of the waste slurry prepared in step (1), 2.2kg of eleostearic acid and 1.8kg of 2 BaO. SiO₂And 3kg of synthetic microbeads, wherein the particle size of the synthetic microbeads is 0.5 mu m, and the analysis result of the components of the treated waste slurry is shown in Table 6 and meets the water requirement of reinforced concrete in JGJ63-2006 Water Standard for concrete.

Example 8: compared with the embodiment 1, the C30 recycled aggregate concrete is characterized in that the concrete raw material also comprises recycled building micro powder, the mass ratio of the recycled building micro powder to the cement is 1:0.3, the recycled building micro powder is prepared from 7, and the preparation method of the C30 recycled aggregate concrete comprises the following steps:

s2, mixing 30kg/m³The recycled aggregate and the recycled building micro powder are mixed evenly and then mixed with 8.2kg/m³195kg/m of fully mixed admixture³Adding water into a mixture of the recycled aggregate and the recycled building micro powder, stirring uniformly, adding a premix, and mixing uniformly to prepare C30 recycled aggregate concrete, wherein the admixture is prepared from preparation example 4, the recycled aggregate comprises activated iron tailings and waste slurry water in a mass ratio of 1:0.3, the activated iron tailings are prepared from preparation example 1, the concentration of the waste slurry water is 2%, and the water quality analysis result of the waste slurry water is shown in Table 5 and meets the water requirement of reinforced concrete in JGJ63-2006 Water for concrete Standard.

Example 9: the C30 recycled aggregate concrete is different from the concrete in example 8 in that the concrete raw material also comprises recycled building micro powder, the mass ratio of the recycled building micro powder to the cement is 1:0.4, and the recycled building micro powder is prepared from 8 parts by mass.

Example 10: the C30 recycled aggregate concrete is different from the concrete in example 8 in that the concrete raw material also comprises recycled building micro powder, the mass ratio of the recycled building micro powder to the cement is 1:0.5, and the recycled building micro powder is prepared from 9.

Comparative example

Comparative example 1: a C30 recycled aggregate concrete is different from the concrete in example 1 in that the iron tailings are not subjected to activation treatment.

Comparative example 2: a C30 recycled aggregate concrete is different from the concrete in example 1 in that the admixture is replaced by an early strength agent which is sold by Shanghai Yunyan industry Co., Ltd and is YG-8016.

Comparative example 3: a recycled aggregate concrete of C30, which is different from the concrete of example 5 in that the waste slurry having a concentration of 10% was not treated in advance.

Comparative example 4: a C30 recycled aggregate concrete, which is different from the concrete of example 5 in that eleostearic acid and 2BaO SiO are not added when waste slurry with the concentration of 10% is treated₂。

Comparative example 5: a recycled aggregate concrete of C30 is different from that of example 5 in that no homomicrobeads were added when treating 10% waste slurry.

Comparative example 6: a C30 recycled aggregate concrete is different from the concrete of example 8 in that dihydrate gypsum and cement clinker are not added into the recycled building micropowder.

Comparative example 7; by taking the recycled aggregate concrete prepared in example 2 of the Chinese invention patent application with the application number of 201910518623.0 as a reference, the components and the parts by weight of the concrete are 25 parts of recycled coarse aggregate, 7 parts of recycled fine aggregate, 45 parts of water, 60 parts of cement, 15 parts of deodorant, 7 parts of plasticizer, 7 parts of admixture, 7 parts of desulfurized gypsum, 25 parts of fly ash, 30 parts of gel material and 30 parts of nano silicon dioxide.

Performance test

Concrete slurry was prepared according to the methods of examples 1 to 10 and comparative examples 1 to 7, and various properties of the concrete were measured according to the following methods, and the measurement results are recorded in table 7:

1. compressive strength: testing according to GB/T50081-2002 'test method for mechanical properties of common concrete';

2. slump: testing according to GB/T50080-2016 standard of common concrete mixture performance test method;

3. sulfate attack resistance: detecting according to GB/T749-2008 'test method for resisting sulfate erosion of cement';

4. diffusion coefficient of chloride ion: testing according to 'unsteady state migration test of concrete chloride ion migration coefficient-chloride ion diffusion coefficient model speed experiment NT BUILD 492' in GB/T50082-2009 Standard test method for Long-term Performance and durability of ordinary concrete;

5. abrasion quality: performing an abrasion resistance test by using a TMS-400 cement mortar abrasion resistance tester, wherein the size of a sample is 15cm multiplied by 3cm, the sample is placed in a pre-curing chamber with the temperature of 20 +/-3 ℃ and the relative humidity of more than or equal to 90 percent for curing for 24 +/-2 h after being molded, the sample is immediately placed in a curing chamber with the temperature of 20 +/-2 ℃ and the humidity of more than or equal to 95 percent for curing to age after being demolded, the sample is taken out of water, is naturally dried in the air, is fully dried at the temperature of less than 60 ℃, is placed on an abrasion resistance machine, is pre-ground for 30 turns under the load of 300N, is taken out, is cleaned, and is weighed, and the weight is used asThe original weight g1, regrinding for 40 turns, taking off the test piece, sweeping the powder, weighing g2, the abrasion loss of the test piece is expressed by the abrasion mass per unit area of each test piece, and the abrasion loss is calculated to be 0.01kg/m²The formula is G ═ G1-G2)/0.0125.

TABLE 7 results of performance test of concrete prepared in examples 1 to 10 and comparative examples 1 to 7

As can be seen from the data in Table 7, by using the activated iron tailings and the waste slurry with the concentration of less than or equal to 8% according to the methods in examples 1 to 4, the prepared concrete has high compressive strength, small slump loss, good workability, less possibility of dispersion, small abrasion loss, and good effect of resisting sulfate ion and chloride ion corrosion.

In examples 5 to 7, the waste slurry with a concentration of more than 8% is treated, and the waste slurry is applied to concrete, and the detection results show that the slump loss of the concrete is small, the sulfate radical erosion resistance is obviously enhanced compared with that of examples 1 to 4, the chloride ion diffusion resistance is improved, and the wear resistance is enhanced.

In the examples 8-10, not only the treated waste slurry with the concentration of more than 8% is used, but also the recycled building micro powder is doped, and the detection result shows that the compression strength of the concrete is obviously increased compared with the examples 1-7, the wear-resisting effect is further improved, and the concrete has higher compression strength and better wear resistance.

In the comparative example 1, the iron tailings are not activated, so that the prepared concrete slurry has the advantages of reduced compressive strength, increased slump loss, reduced erosion resistance to chloride ions and sulfate ions and poor wear resistance compared with the concrete slurry prepared in the example 1.

Comparative example 2 since a commercially available admixture was used instead of the admixture prepared according to the present invention, it was found from the results of the test that the concrete prepared according to comparative example 2 had compression strength and slump loss comparable to those of example 1, but the corrosion resistance and wear resistance of the concrete were significantly reduced.

Comparative example 3 since the concrete was prepared using the untreated waste slurry having a concentration of 10%, the compression strength, slump loss, and abrasion resistance of the concrete were reduced and the corrosion resistance was reduced compared to example 5, which shows that the treatment of the waste slurry having a concentration of 8% or more using the method of the present invention can reduce the slump loss, improve the strength of the concrete, and enhance the corrosion resistance of the concrete.

Comparative example 4 Eleostearic acid and 2 BaO. SiO were not added when treating 10% waste water₂Compared with example 5, the concrete has a reduced ability to resist attack by sulfate ions and chloride ions, and has a reduced abrasion resistance and compressive strength.

Comparative example 5 since no homo-beads were added when 10% of the waste slurry water was treated, the viscosity of the concrete was higher, the slump loss of the concrete was large, the workability was poor, and the compressive strength was reduced, as compared with example 5.

In comparative example 6, after 10% of waste slurry is treated, cement clinker and dihydrate gypsum are not added into the regenerated building micro powder, so that the compressive strength of concrete is reduced, and the wear resistance is reduced.

Comparative example 7 is recycled aggregate concrete prepared by the prior art, which has high compressive strength but poor corrosion resistance and abrasion resistance.

The present embodiment is only for explaining the present invention, and it is not limited to the present invention, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present invention.

Claims

1. The C30 recycled aggregate concrete is characterized by comprising the following components in parts by weight: 230-270 parts of cement, 80-100 parts of mineral powder, 50-70 parts of fly ash, 770-810 parts of sand, 925-965 parts of stones, 155-195 parts of water, 8.2-10.2 parts of additive and 30-60 parts of recycled aggregate;

2. The C30 recycled aggregate concrete of claim 1, wherein the weight parts of the components are as follows: 24-260 parts of cement, 85-95 parts of mineral powder, 55-65 parts of fly ash, 780-sand, 935-gravel, 165-185 parts of water, 8.7-9.7 parts of additive and 40-50 parts of recycled aggregate;

3. The C30 recycled aggregate concrete according to any one of claims 1-2, wherein the waste water concentration exceeding 8% is treated by: (1) passing the waste slurry through a sand-stone separation device, wherein the aperture of a screen in the sand-stone separation device is 0.15-0.2mm, adding clear water with the total amount of 2-4 times of that of the separated waste slurry, and uniformly mixing;

4. The C30 recycled aggregate concrete according to any one of claims 1-2, wherein the admixture is prepared by the following method:

5. The C30 recycled aggregate concrete of claim 4, wherein the water reducer is one or a combination of a polycarboxylic acid high-efficiency water reducer and a naphthalene sulfonate formal high-efficiency water reducer.

6. The C30 recycled aggregate concrete according to any one of claims 1-2, wherein the raw materials further comprise recycled building micro powder, the mass ratio of the recycled building micro powder to the cement is 1:0.3-0.5, and the recycled building micro powder comprises the building garbage micro powder, the dihydrate gypsum and the cement clinker in the mass ratio of (1-3): (0.2-0.4): 0.6-0.8).

7. The C30 recycled aggregate concrete of claim 6, wherein the preparation method of the recycled building micropowder is as follows: crushing the construction waste into particles of 30-40mm, calcining for 1-2h at the temperature of 400-.

8. The C30 recycled aggregate concrete according to any one of claims 1-2, wherein the sand is river sand in the area II, the fineness modulus is 3.0-2.3, and the mud content is 2.3-2.5%; the particle size of the stones is 5-31.5mm, the continuous gradation is realized, and the mud content is 0.3-0.5%.

9. The C30 recycled aggregate concrete according to any one of claims 1-2, wherein the fly ash is class F class II fly ash, the fineness (45 μm square mesh screen residue) is less than or equal to 12%, the water demand ratio is 95-98%, and the loss on ignition is less than or equal to 4.5%; the mineral powder is S95 grade mineral powder, the specific surface area of the mineral powder is 400-450m2/kg, the activity index in 28 days is 95%, and the fluidity ratio is 99%.

10. A method for preparing C30 recycled aggregate concrete according to any one of claims 1 to 9, comprising the following steps: