High-crack-resistance large-volume concrete prepared from metallurgical solid wastes and method thereof
阅读说明：本技术 一种利用冶金固废制备高抗裂大体积混凝土及其方法 (High-crack-resistance large-volume concrete prepared from metallurgical solid wastes and method thereof ) 是由 耿继双 徐鹏飞 王飞 吴文浩 李德刚 郭秀丽 李晓伟 赵小燕 郭春媛 张大利 于 2021-07-21 设计创作，主要内容包括：本发明公开了一种利用冶金固废制备高抗裂大体积混凝土及其方法,混凝土各组分为：胶凝材料100份,粗骨料196～370份,细骨料132～325份,高效减水剂0.3～2.2份,由纳米硅灰石粉0.1～5份、转炉二次除尘灰0.1～5份、冷轧废乳化液0.5～25份、氧化铁粉0.00625～0.0125份、硫酸钠0.0125～0.025份、乙二醇0.0125～0.025份组成的外加剂,水32～62份。制备方法为：先将粗、细骨料混合,加入胶凝材料混合,再加高效减水剂和补充用水混合,在加入减水剂和补充用水之前或者同时加入经消解处理后的转炉二次除尘灰和经分散处理后的纳米硅灰石粉。本发明的混凝土具有制造成本低,有害孔数量少,强度高,抗徐变性能强,低收缩,高抗裂,大体积等特点,混凝土中冶金固废掺量≥75％。(The invention discloses a method for preparing high-crack-resistance large-volume concrete by utilizing metallurgical solid wastes, and the method comprises the following steps: 100 parts of cementing material, 196-370 parts of coarse aggregate, 132-325 parts of fine aggregate, 0.3-2.2 parts of high-efficiency water reducing agent, an additive consisting of 0.1-5 parts of nano wollastonite powder, 0.1-5 parts of converter secondary dedusting ash, 0.5-25 parts of cold rolling waste emulsion, 0.00625-0.0125 parts of iron oxide powder, 0.0125-0.025 parts of sodium sulfate, 0.0125-0.025 parts of ethylene glycol and 32-62 parts of water. The preparation method comprises the following steps: mixing coarse and fine aggregates, adding a cementing material, mixing, adding a high-efficiency water reducing agent and supplementing water, and adding the converter secondary dedusting ash subjected to digestion treatment and the nano wollastonite powder subjected to dispersion treatment before or simultaneously adding the water reducing agent and the supplementing water. The concrete of the invention has the characteristics of low manufacturing cost, small number of harmful holes, high strength, strong creep resistance, low shrinkage, high crack resistance, large volume and the like, and the metallurgical solid waste mixing amount in the concrete is more than or equal to 75 percent.)
1. The method for preparing the high-crack-resistance large-volume concrete by utilizing the metallurgical solid wastes is characterized by comprising the following components in parts by weight: 100 parts of cementing material, 196-370 parts of coarse aggregate, 132-325 parts of fine aggregate, 0.3-2.2 parts of high efficiency water reducing agent, an additive consisting of 0.1-5 parts of converter secondary dedusting ash, 0.1-5 parts of nano wollastonite powder, 0.5-25 parts of cold rolling waste emulsion, 0.00625-0.0125 parts of iron oxide powder, 0.0125-0.025 parts of sodium sulfate and 0.0125-0.025 parts of ethylene glycol, and 32-62 parts of water.
2. The method for preparing the high crack resistance large-volume concrete by using the metallurgical solid waste is characterized in that a cementing material comprises 50-75 parts of cement, 13-8 parts of slag micro powder, 13-5 parts of steel slag micro powder, 12-5 parts of fly ash and 12-7 parts of iron tailing powder; the high-efficiency water reducing agent is one or a mixture of two of polycarboxylic acid and naphthyl; the water is used for proportioning the concrete and comprises water for digesting secondary fly ash in the converter, water contained in cold-rolled waste emulsion for dispersing nano wollastonite powder and supplementary water.
3. The method for preparing the high anti-cracking large-volume concrete by using the metallurgical solid waste is characterized in that the coarse aggregate is continuously graded mine waste stone, the particle size range is 5-20 mm, the Mohs hardness is 5-7, and the crushing value is less than or equal to 10%; the fine aggregate is mine waste rock artificial sand and iron tailing sand, the crushing value is less than or equal to 25 percent, the proportion of the mine waste rock artificial sand is 90-10 percent, the proportion of the iron tailing sand is 10-90 percent, the mine waste rock artificial sand and the iron tailing sand are mixed to form continuous gradation, and the grain size is less than or equal to 5 mm; the fineness modulus of the mine waste rock artificial sand in the fine aggregate is 2.2-3.6, the iron tailing sand is divided into two types of coarse and fine, the fineness modulus of the coarse iron tailing sand is 2.1-3.5, the fineness modulus of the fine iron tailing sand is 0.7-1.8, and the amount of the particle diameter d less than or equal to 0.16mm accounts for 8-20% of the amount of the fine iron tailing sand.
4. The method for preparing the high anti-cracking large-volume concrete by utilizing the metallurgical solid waste is characterized in that the converter secondary fly ash is fly ash obtained by magnetic separation and iron removal of converter secondary dry fly ash, the converter secondary dry fly ash contains 6-11% of CaO and 3-6% of MgO, the particle size is more than 5000 meshes, the particle size of the converter secondary dry fly ash is more than 95% of the particle size of 0.1-30 microns, and the iron removal rate of the converter secondary dry fly ash is more than or equal to 80%.
5. The method for preparing the high crack-resistant large-volume concrete by using the metallurgical solid waste as claimed in claim 1 or 4, wherein the amount of converter secondary dust ash required for the strength grade C20 concrete is 0.1-0.4 part, the amount of converter secondary dust ash required for the strength grade C30 concrete is 0.5-1.4 parts, the amount of converter secondary dust ash required for the strength grade C40 concrete is 1.5-2.4 parts, the amount of converter secondary dust ash required for the strength grade C50 concrete is 2.5-3.4 parts, the amount of converter secondary dust ash required for the strength grade C55 concrete is 3.5-4.4 parts, and the amount of converter secondary dust ash required for the strength grade C60 concrete is 4.5-5.0 parts.
6. The method for preparing the high-crack-resistance large-volume concrete by using the metallurgical solid waste as claimed in claim 1, wherein the nano wollastonite powder has a particle size of 10-100 nm, a length-diameter ratio of 7-20: 1 and Ca3Si3O9Not less than 30 percent, and the specific surface area is 30000m2A hydrophilic material of/kg or more; the particle size of the iron oxide powder is 0.1 to 1 μm.
7. The method for preparing the high-crack-resistance large-volume concrete by using the metallurgical solid waste according to any one of claims 1 to 6, which comprises the steps of mixing coarse and fine aggregates in a stirring tank, adding a cementing material, mixing, adding a high-efficiency water reducing agent and supplementing water, mixing, and injecting the mixture into a concrete transport vehicle after stirring, wherein a mixture of converter secondary fly ash subjected to digestion treatment and nano wollastonite powder subjected to dispersion treatment is added into the stirring tank before or simultaneously with the addition of the high-efficiency water reducing agent and the supplementing water.
8. The method for preparing the high anti-cracking large-volume concrete by using the metallurgical solid waste according to claim 7, wherein the digestion treatment method of the converter secondary fly ash comprises the following steps: and (3) putting the secondary dedusting ash of the converter and water with the amount of 2-3 times of the secondary dedusting ash into a stirring device, mixing and stirring for more than 6 hours, and promoting the digestion reaction of the f-CaO and the f-MgO.
9. The method for preparing the high anti-crack large-volume concrete by using the metallurgical solid wastes according to claim 7, wherein the dispersion treatment method of the nano wollastonite powder comprises the following steps: and (2) putting 0.5-25 parts of cold rolling waste emulsion into a stirring device, starting stirring, firstly adding 0.00625-0.0125 parts of iron oxide powder, and then sequentially adding 0.1-5 parts of nano wollastonite powder, 0.0125-0.025 parts of sodium sulfate and 0.0125-0.025 parts of ethylene glycol to form uniformly and stably dispersed nano wollastonite slurry.
10. The method for preparing the high anti-crack large-volume concrete by using the metallurgical solid waste according to claim 9, wherein the initial stirring speed of a stirring device is controlled to be 800-1200 rpm, the iron oxide powder is added and stirred for 2-3 minutes, the nano wollastonite powder is divided into 3-5 equal parts, and the stirring is continued for 3-5 minutes after the nano wollastonite powder is added in batches; and adding sodium sulfate, continuously stirring for 3-5 minutes, finally adding ethylene glycol, stirring for 10-15 minutes, reducing the stirring speed to 100-150 rpm, stirring for 5-10 minutes, and stopping stirring.
Technical Field
The invention belongs to the field of building materials, and particularly relates to high-crack-resistance large-volume concrete prepared by utilizing metallurgical solid wastes and a method thereof.
Background
In recent years, researchers continuously explore methods for modifying concrete by adding nano materials, and find that the nano materials can improve the mechanics and durability of the concrete mainly due to the mechanisms of promoting hydration, enabling hydration products to be uniform, enabling crystals to be refined and compact, improving an interface area, reducing porosity, refining microcracks under load and the like. By adopting a nano assembly technology, the nano material grows or is grafted on the micron-sized mineral admixture and the fiber to form the micro-nano multi-scale material, on one hand, the problem that the nano material can still be uniformly dispersed in concrete under a large doping amount can be solved, on the other hand, the microstructure of the concrete can be obviously improved through a fiber space network, a micro-nano scale effect and the treatment of the nano material on the fiber surface, and the deformability and the shock resistance of the nano-scale material are far superior to those of common high-strength concrete.
However, the micro-nano material can improve the performance indexes of concrete such as compressive strength and the like, has limited improvement on the performance indexes of bending resistance and the like, and is not obvious particularly in the aspects of shrinkage resistance and crack resistance of mass concrete. The concrete used in the part with the entity minimum size more than or equal to 1m in the structure is considered to be large-volume concrete in the JGJ/T55 standard of China. The crack resistance of concrete is the comprehensive performance of concrete, and has a certain relation with tensile strength, ultimate tensile deformation capacity, tensile elastic modulus, autogenous volume deformation, creep and thermal performance.
1. In the composite concrete (application number: CN201910491654.1), in the pouring solidified body, a cement substitute is blast furnace dust which accounts for not more than 15% of the total weight of the cement and the substitute, and the percentage of the blast furnace dust accounts for 5-10% of the total weight of the cement and the substitute. The blast furnace dust replaces part of cement, has limited gelatinization and plays a simple filling role.
2. The mass conductive concrete (application number: CN 201711348518.4) based on the ironmaking dust comprises 5-25 parts of ironmaking dust, wherein the ironmaking dust contains 5-65% of carbon, 10-60% of iron and impurities in percentage by mass. The ironmaking fly ash has high carbon content and iron content, is limited in resisting the shrinkage of concrete, and is not suitable for preparing large-volume concrete.
Disclosure of Invention
The invention aims to provide high-crack-resistance large-volume concrete prepared by utilizing metallurgical solid wastes and a method thereof, which utilize the micro-expansion effect of the digestion reaction of converter secondary dry method fly ash after iron removal treatment, the hydration reaction of nano wollastonite powder and the synergistic effect of other metallurgical solid wastes to meet the requirement of the application performance of high-crack-resistance large-volume concrete, simultaneously improve the reutilization of mine waste rock, iron tailings, converter secondary dry method fly ash and nano wollastonite powder, reduce CO2The discharge of (2) and the production cost is effectively reduced.
The sand and stone material used by the concrete prepared by the method can completely use metallurgical solid wastes, and the mixing amount of the metallurgical solid wastes in the concrete is more than or equal to 75 percent.
In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:
the method for preparing the high-crack-resistance large-volume concrete by utilizing the metallurgical solid wastes comprises the following components in parts by weight: 100 parts of cementing material, 196-370 parts of coarse aggregate, 132-325 parts of fine aggregate, 0.3-2.2 parts of high efficiency water reducing agent, an additive consisting of 0.1-5 parts of converter secondary dedusting ash, 0.1-5 parts of nano wollastonite powder, 0.5-25 parts of cold rolling waste emulsion, 0.00625-0.0125 parts of iron oxide powder, 0.0125-0.025 parts of sodium sulfate and 0.0125-0.025 parts of ethylene glycol, and 32-62 parts of water.
Further, the cementing material comprises 50-75 parts of cement, 13-8 parts of slag micro powder, 13-5 parts of steel slag micro powder, 12-5 parts of fly ash and 12-7 parts of iron tailing powder; the high-efficiency water reducing agent is one or a mixture of polycarboxylic acids and naphthyl; the water is used for proportioning concrete, and comprises converter secondary dedusting ash digestion water, cold rolling waste emulsion for dispersing nano wollastonite powder, and supplementary water.
The cement is Portland cement (P. I, P. II), ordinary Portland cement (P.O), composite Portland cement (P.C), 42.5, 52.5. The fineness of the slag micro powder and the steel slag micro powder is more than 400 meshes, and the grade of S75 and above is recommended. The fly ash reaches more than II grade, and the granularity reaches more than 400 meshes. The iron tailing powder is prepared by grinding iron tailings, and the granularity reaches more than 400 meshes. The cement, slag micropowder and steel slag micropowder have hydraulic activity; the glass microspheres in the fly ash can improve and enhance the structural strength of concrete, improve homogeneity and compactness, and a large amount of active silicon dioxide, alumina and alkaline substances generate gelled substances such as calcium silicate hydrate and calcium aluminate hydrate and the like to block capillary tissues of the concrete and improve impermeability; the iron tailings powder has the characteristic of high interfacial activity, and the materials can participate or promote the formation of hydration products, so that the compressive strength and the flexural strength of the concrete are enhanced.
Further, the coarse aggregate is continuously graded mine waste stone, and the particle size range is 5-20 mm; the fine aggregate is mine waste rock artificial sand and iron tailing sand, wherein the proportion of the mine waste rock artificial sand is 90-10%, the proportion of the iron tailing sand is 10-90%, the mine waste rock artificial sand and the iron tailing sand are mixed to form continuous gradation, and the grain size is less than or equal to 5 mm.
The mine waste rock is waste rock after stripping and ore processing, which is discharged in the mining process, the Mohs hardness is 5-7, the broken stone strength reaches the hardness of limestone and basalt, the strength is high, and the skeleton and the supporting function are achieved in concrete.
Processing and crushing mine waste rocks into 20mm and below, wherein the artificial sand of the waste rocks with the size less than or equal to 5mm is used as fine aggregate; the size of the mine waste stone is 5-20 mm, the size of the mine waste stone is used as a coarse aggregate, the crushing value is less than or equal to 10%, and the mine waste stone is in continuous gradation, so that the strength is improved and pumping is facilitated.
According to the relevant industry standards, the fine aggregate is divided according to the fineness modulus: 3.1-3.7 of coarse sand, 2.3-3.0 of medium sand and 1.6-2.2 of fine sand. The crushing value of the fine aggregate is less than or equal to 25 percent, wherein the fineness modulus of the artificial sand of the mine waste rock is 2.2-3.6, and the artificial sand belongs to the range of medium sand or coarse sand; the iron tailing sand in the fine aggregate is divided into two types of coarse and fine, wherein the coarse iron tailing sand is waste sandstone separated by a pre-selection process, the fineness modulus is 2.1-3.5, and the range of medium sand and even coarse sand is reached; the fine iron tailing sand is ore waste obtained by grinding magnetite and selecting iron by a magnetic separation process, is stirred and mixed with water, is discharged to a tailing pond through a pipeline, is settled to obtain sandstone, has the fineness modulus of 0.7-1.8, is smaller than the fineness modulus of the fine sand, belongs to extremely fine sand, and accounts for 8-20% of the fine iron tailing sand by the amount of the particle size d being less than or equal to 0.16 mm. The fine iron tailing sand has high interfacial activity and promotes the hydration reaction with the cementing material.
Further, the converter secondary dry dedusting ash is secondary flue gas generated in the processes of adding molten iron, adding scrap steel, blowing, tapping, deslagging and slag splashing protection of the converter, one part is flue gas dedusting ash in the converter smelting process, the other part is fine particles of a bin raw material entering the converter and entering a dedusting system along with the flue gas, and the fine particles are about 0.35-0.4 kg/t of steel, wherein the content of CaO in the converter secondary dry dedusting ash is 6-11%, the content of MgO is 3-6%, the particle size is more than 5000 meshes, and the particle size of the converter secondary dry dedusting ash is more than 95% of the particle size of 0.1-30 mu m. The converter secondary fly ash (hereinafter referred to as 'secondary ash') is fly ash obtained by magnetically separating and removing iron from converter secondary dry fly ash, and the iron removal rate of the converter secondary dry fly ash is more than or equal to 80%.
The main components participating in hydration reaction in the concrete are f-CaO and f-MgO which are dispersedly distributed and not digested, the digestion is continued, the hydration reaction with the cementing material is carried out to promote the micro-expansion of the concrete, the shrinkage of the concrete in the solidification process can be counteracted, and the micro-expansion, high crack resistance and large-volume concrete is constructed under the synergistic effect of the nano wollastonite powder.
CaO+H2O＝Ca(OH)2(exothermic reaction)
MgO+H2O＝Mg(OH)2(exothermic reaction, slow)
The reaction volume expansion of f-CaO and water is increased by 98%, and the reaction volume expansion of f-MgO and water is increased by 148%.
The furnace temperature is higher than 1500 ℃ in the converter smelting process, the components such as C3S (tricalcium silicate), C2S (dicalcium silicate), C3A (tricalcium aluminate), C4AF (tetracalcium aluminoferrite) and the like formed in the furnace slag are contained, part of slag particles are collected as fine ash along with flue gas in the blowing, tapping, slag discharging and slag splashing furnace protection processes, and the components can be all participated in concreteReacting with water to generate C-S-H gel, Ca (OH)2Crystal, ettringite AFt or AFm, and the like.
Furthermore, the invention mainly prepares concrete with the strength of C20-C60. And (3) carrying out pre-mixing, stirring and digesting for more than 6 hours according to the secondary ash amount required by the concrete strength grade, wherein the water amount is 2-3 times of the secondary ash amount, so that the digestion reaction of the f-CaO and the f-MgO is promoted, and the reaction heat is released in advance. 0.1-0.4 part of secondary ash required by strength grade C20 concrete, 0.5-1.4 parts of secondary ash required by strength grade C30 concrete, 1.5-2.4 parts of secondary ash required by strength grade C40 concrete, 2.5-3.4 parts of secondary ash required by strength grade C50 concrete, 3.5-4.4 parts of secondary ash required by strength grade C55 concrete and 4.5-5.0 parts of secondary ash required by strength grade C60 concrete.
Further, wollastonite is a naturally occurring crystalline material, a chain silicate, selected from alpha-CaSiO3Type wollastonite, namely low-temperature triclinic wollastonite, nano wollastonite powder with the particle size of 10-100 nm and the length-diameter ratio of 7-20: 1, Ca3Si3O9Not less than 30 percent, and the specific surface area is 30000m2A hydrophilic material in an amount of more than kg. Wollastonite waste rock is recommended.
The nanometer wollastonite powder has large specific surface area, adsorption effect and high activity, participates in hydration reaction of concrete, wollastonite fibers are distributed in nanometer C-S-H gel in a staggered manner, C-S-H nanometer nucleation enables macropores to be reduced, the pore diameter of bubbles is uniform, harmful pores in the concrete are reduced, and more harmless pores and less harmful pores (pore diameter:<20nm is harmless hole; 20 nm-50 nm is a less harmful hole; 50 nm-200 nm is harmful pores;>200nm is a multiple hole). The concrete structure is more compact, the fracture toughness of the concrete is improved, the crack resistance and the shock resistance of the concrete are enhanced, the needle-shaped AFt and the layered C-S-H are reduced, the anti-permeability performance of the concrete is enhanced, the corrosion resistance is improved, the early strength and the later strength of the concrete are improved, and the creep resistance of the concrete can be improved. Meanwhile, the wollastonite has a low coefficient of thermal expansion of 6.5 multiplied by 10-6mm/(mm DEG C), is suitable for preparing concrete with smaller expansion.
The nano wollastonite powder promotes the formation of hydrated components and the structural compactness of the interface of the secondary ash and the set cement, and enhances the activity of the nano wollastonite powder and the alkali-activated activity. In the hydration process of concrete, the hydration product can use wollastonite fiber as crystal seed to grow continuously on the fiber, and the nanometer wollastonite fiber plays the role of 'pinning' reinforcement and toughening in various directions in the concrete, so that the compression strength and the breaking strength of the concrete are increased.
Further, in order to solve the problem of poor agglomeration and dispersibility of the nano wollastonite powder, the method for dispersing the nano wollastonite powder by using the cold rolling waste emulsion is adopted, and the nano wollastonite powder, the cold rolling waste emulsion and other medicaments are prepared according to the following mass parts of 0.1-5 parts of the nano wollastonite powder, 0.5-25 parts of the cold rolling waste emulsion, 0.00625-0.0125 part of iron oxide powder, 0.0125-0.025 part of sodium sulfate and 0.0125-0.025 part of ethylene glycol. The specific dispersion method comprises the following steps: firstly, placing cold rolling waste emulsion into a stirring device, controlling the stirring speed at 800-1200 rpm, adding iron oxide powder, stirring for 2-3 minutes, dividing nano wollastonite powder into 3-5 equal parts, adding in batches at an interval of 3-5 minutes, adding sodium sulfate, and continuously stirring for 3-5 minutes; and finally, adding ethylene glycol, stirring for 10-15 minutes, reducing the stirring speed to 100-150 rpm, stirring for 5-10 minutes, and stopping stirring to form uniformly and stably dispersed nano wollastonite slurry, wherein the nano wollastonite powder has good dispersibility in a concrete body and high integral performance of the concrete.
The cold rolling waste emulsion mainly contains water, the water content is 96.5-97.5%, the rest 2.5-3.5% contains synthetic ester, surfactant, anticorrosive additive and extreme pressure additive, and active functional groups contained in the emulsion can adsorb nano wollastonite powder, so that the dispersion of the nano wollastonite powder is facilitated.
The particle size of the iron oxide powder is 0.1-1 mu m, and the nano wollastonite powder is easy to adsorb and bond with the iron oxide powder due to large surface energy, and the iron oxide powder can promote the formation of calcium sulphoaluminate in concrete along with the dispersion of the iron oxide powder in a solution.
The sodium sulfate and the nano wollastonite powder are dispersed together in the solution, so that the agglomeration of the nano wollastonite powder in the concrete stirring process is prevented. The sodium sulfate can form calcium sulfoaluminate hydrate with cement, slag micropowder and steel slag micropowder in the cementing material more quickly in the concrete solidification process, the early strength of the concrete is improved, the hydration process of the cementing material is accelerated, and the two actions are mutually promoted.
The ethylene glycol can improve the stability of the nano wollastonite grout, and can release and resolve internal shrinkage or expansion stress caused by hydration reaction before concrete is solidified by taking the ethylene glycol as a retarder of the cement, and can dissolve part of inorganic salt contained in the cement, so that the salt in the cement is not easy to seep out, the concrete is more compact after being solidified, and the strength of the concrete is enhanced.
The invention relates to a method for preparing high-crack-resistance large-volume concrete by utilizing metallurgical solid wastes, which comprises the steps of mixing coarse and fine aggregates in a stirring tank, adding a cementing material for mixing, adding a high-efficiency water reducing agent and supplementing water for mixing, injecting into a concrete transport vehicle after stirring, adding two mixtures of digested secondary ash and dispersed nano wollastonite powder into the stirring tank before or simultaneously adding the high-efficiency water reducing agent and the supplementing water.
According to the scheme, the high-crack-resistance large-volume concrete prepared by utilizing metallurgical solid wastes has the following beneficial effects:
1. when preparing the C20-C60 strength concrete, curing under normal temperature and normal humidity conditions, and performing standard curing on the prepared concrete test piece to obtain 28d compressive strength of 26.7 MPa-80.6 MPa; the 28d flexural strength is 3.5-8.7 Mpa; the expansion rate of the concrete is-0.010% -0.004%.
2. The problem of concrete cracking can be effectively solved by adopting the secondary ash and the nano wollastonite powder, f-CaO and f-MgO which are not digested in the secondary ash are continuously digested in the concrete solidification process, and the f-CaO and the f-MgO undergo hydration reaction with a cementing material to promote the micro-expansion of the concrete, so that the shrinkage of the concrete in the solidification process can be counteracted.
3. The concrete structure is more compact, the fracture toughness of the concrete is improved, the crack resistance and the shock resistance of the concrete are enhanced, the impermeability is enhanced, the corrosion resistance is improved, the early strength and the later strength of the concrete are improved, the creep resistance of the concrete can be improved, and the concrete is suitable for constructing high-crack-resistance and large-volume concrete.
4. The metallurgical solid waste mixing amount in the concrete is more than or equal to 75 percent, and the usage amount of fine iron tailing sand with the grain diameter d less than or equal to 0.16mm accounting for 8 to 20 percent is increased; the manufacturing cost of the concrete is reduced by 20-70 yuan/m3。
Detailed Description
1. The raw material components used in the present invention
TABLE 1 mine waste Stone composition Range (Unit:%)
Composition (I)
SiO2
Al2O3
FeO
Fe2O3
TFe
CaO
MgO
K2O
Na2O
Data of
50～78
5～18
0.5～8
1～8
0.3～6
2～10
1～5
0～4
0～4
The Mohs hardness is 5-7.
TABLE 2 composition Range of iron tailings (containing magnetic tailings and pre-selected process tailings) (Unit:%)
Composition (I)
SiO2
Al2O3
FeO
Fe2O3
TFe
CaO
MgO
K2O
Na2O
Data of
55～82
0.2～9
0.5～12
2～22
5～15
0～8
0～4
0～1.8
0～1.8
TABLE 3 composition range of secondary dry fly ash (before iron removal) in converter (unit:%)
Composition (I)
TFe
Fe2O3
FeO
CaO
MgO
SiO2
Al2O3
C
Data of
53～66
65～75
9～13
6～11
3～6
1～3
0.1～0.5
0.5～3
TABLE 4 composition range of converter secondary fly ash (after iron removal) (unit:%)
Composition (I)
TFe
Fe2O3
FeO
CaO
MgO
SiO2
Al2O3
C
Data of
10.6～13.2
13～15
1.8～2.6
16.2～55
8.1～30
2.7～15
0.3～2.5
1.8～15
2. Technological parameters of the invention
1) The digestion treatment method of the secondary ash comprises the following steps: and (3) calculating the amount of the added secondary ash and the amount of water with the amount of 2-3 times of the secondary ash according to the concrete strength grade, premixing the secondary ash and the f-MgO to promote the digestion reaction of the f-CaO and the f-MgO for more than 6 hours, and referring to table 8.
2) The invention discloses a dispersion treatment method of nano wollastonite powder, which comprises the following steps: putting 0.5-25 parts of cold rolling waste emulsion into a stirring device, controlling the stirring speed at 800-1200 rpm, adding 0.00625-0.0125 parts of iron oxide powder, stirring for 2-3 minutes, dividing 0.1-5 parts of nano wollastonite powder into 3-5 equal parts, and adding in batches at intervals of 3-5 minutes; and adding 0.0125-0.025 parts of sodium sulfate, continuously stirring for 3-5 minutes, finally adding 0.0125-0.025 parts of ethylene glycol, stirring for 10-15 minutes, reducing the stirring speed to 100-150 rpm, stirring for 5-10 minutes, and stopping stirring to form the uniformly dispersed and stable nano wollastonite slurry. The detailed process parameters are shown in Table 5.
TABLE 5 Dispersion treatment Process parameters of Nano wollastonite powder
3) The content and the particle size range of the components in the secondary dry-process fly ash of the concrete transfer furnace of each strength grade and Ca in wollastonite3Si3O9And (4) content.
TABLE 6 content and particle size distribution of some components in converter secondary dry dedusting ash and wollastonite (unit:%)
4) Fine aggregate proportioning scheme
TABLE 7 concrete fine aggregate proportioning scheme (unit:%)
5) Water quantity of each part
And (3) carrying out digestion reaction on the secondary ash amount and water, wherein the water amount is 2-3 times of the secondary ash amount (the water for digestion reaction is ignored).
0.1-5 parts of nano wollastonite powder and 0.5-25 parts of cold-rolling waste emulsion (the average value of the water content of the cold-rolling waste emulsion is 97%).
The water content is the water content of the cold rolling waste emulsion, the secondary ash digestion water and the water required to be supplemented (see table 8).
TABLE 8 Water volume of each part (unit: number of parts)
6) The adding mode of each raw material is as follows: and uniformly mixing the coarse aggregate, the fine aggregate and the cementing material according to the normal concrete stirring mode. When concrete is produced, adding the digested secondary ash and the dispersed nano wollastonite powder before or simultaneously adding the water reducing agent and the supplementary water (the secondary ash and the dispersed nano wollastonite powder are added before in examples 1 to 3 and simultaneously added in examples 4 to 6). The slump is more than or equal to 160 mm.
3. The concrete proportion and the performance of the invention
Example 1: (in the concrete proportioning scheme, the unit is part, the 28d strength unit is MPa, and the 28d expansion rate is:%)
Example 2: (in the concrete proportioning scheme, the unit is part, the 28d strength unit is MPa, and the 28d expansion rate is:%)
Example 3: c40 (concrete proportioning in the unit: portion; 28d strength unit: MPa; 28d expansion ratio:%)
Example 4: (in the concrete proportioning scheme, the unit is part, the 28d strength unit is MPa, and the 28d expansion rate is:%)
Example 5: (in the concrete proportioning scheme, the unit is part, the 28d strength unit is MPa, and the 28d expansion rate is:%)
Example 6: (in the concrete proportioning scheme, the unit is part, the 28d strength unit is MPa, and the 28d expansion rate is:%)
Comparative example: (in the concrete proportioning scheme, the unit is part, the 28d strength unit is MPa, and the 28d expansion rate is:%)
Note: the C20-C60 concrete artificial macadam refers to waste stones (5-20 mm); the artificial sand refers to mine waste rock artificial sand (less than or equal to 5 mm); the tailings powder refers to iron tailings powder; the iron tailing sand is formed by mixing coarse tailing sand and fine tailing sand according to a proportion.
Compared with the comparative example, the compressive strength is improved by 9.96 percent, and the flexural strength is improved by 14.47 percent in the example 6; example 6 slightly expanded with an expansion ratio of 0.004%, and comparative example contracted with an expansion ratio of-0.006%.