Concrete composition, concrete as well as preparation method and application of concrete

Abstract

The invention relates to a concrete composition, concrete as well as a preparation method and application of the concrete. The concrete composition comprises the following components: coal gangue aggregate, a gel material and a water reducing agent, the coal gangue aggregate comprises crushed coal gangue, a coarse coal gangue material and coal gangue stone powder, and the average particle size of the coarse coal gangue material is larger than that of the coal gangue stone powder and smaller than that of the crushed coal gangue; the gel material comprises slag, gypsum and carbide slag. According to the concrete composition, the coal gangue of different grades is adopted as the aggregate and compounded with the gel material and the water reducing agent to prepare the concrete, all the raw materials have a synergistic effect, the durability, workability, crack resistance and other performance of the concrete are improved, the production cost is reduced, and the requirement of coal mine construction for high-performance concrete is met.

Description

Technical Field

[0001] The present application relates to the technical field of building materials, and in particular to a concrete and a preparation method and application thereof. Background Art

[0002] Gangue is a solid waste generated during coal mining and washing. Its large accumulation not only occupies land resources, but also may pollute the environment. In recent years, with the deepening of the concepts of green building and circular economy, the comprehensive utilization of gangue has become a research hotspot. Processing gangue into machine-made aggregate and applying it to concrete preparation is one of the effective ways to realize the resource utilization of gangue. However, since gangue aggregate contains a certain amount of impurities such as combustibles, clay minerals and sulfides, its performance is different from that of natural aggregates, such as low strength, high water absorption, poor interfacial adhesion, etc. These characteristics make it difficult for concrete using gangue as aggregate to meet the requirements, thus limiting its application in high-performance concrete. Summary of the invention

[0003] Based on this, it is necessary to provide a concrete and a preparation method and application thereof to improve the performance of concrete based on coal gangue aggregate.

[0004] In a first aspect of the present application, a concrete composition is provided, which comprises the following components: coal gangue aggregate, a gel material and a water reducer; the coal gangue aggregate comprises coal gangue crushed stone, coal gangue coarse material and coal gangue stone powder, and the average particle size of the coal gangue coarse material is larger than the average particle size of the coal gangue stone powder and smaller than the average particle size of the coal gangue crushed stone; the gel material comprises slag, gypsum and carbide slag.

[0005] The concrete composition of the present application adopts coal gangue of different grades as aggregate and is compounded with gel material and water reducing agent to make concrete. The various raw materials synergize to improve the strength, impermeability, interface adhesion, durability, workability and crack resistance of the concrete.

[0006] The three-grade design of gangue aggregate, namely gangue crushed stone, gangue coarse material and gangue stone powder, can optimize the density and strength of concrete; by adjusting the grading of gangue aggregate, the porosity of concrete can be reduced and the density and strength grade of concrete can be improved.

[0007] The fine particles in slag can fill the voids in concrete, and its active ingredients can react with hydration products to generate new hydration products, thereby improving the concrete's impermeability and durability. When slag-compounded gypsum and carbide slag are used together, the sulfate in the gypsum can stimulate the activity of the remaining solid waste raw materials in the gel material, allowing the solid waste materials to react with the hydration products more quickly, thereby improving the early strength of the clinker-free gelling system, and can regulate the setting time to make the setting process of concrete more reasonable, while also improving the concrete's later strength and microstructure density; when slag-compounded gypsum and carbide slag are used together, the carbide slag cooperates with the stimulating effect of gypsum, and the alkaline components in the carbide slag can react with the sulfate in the gypsum, further stimulating the activity of the remaining solid waste raw materials in the gel material, thereby further improving the strength and durability of the concrete.

[0008] The addition of water reducer can improve the working properties of concrete such as fluidity and pumpability, and can also enhance the strength and durability of concrete after hardening.

[0009] The concrete composition uses a gel material composed entirely of solid waste raw materials, omits cement, reduces the production cost of concrete, and realizes the resource utilization of solid waste. The concrete composition uses coal gangue aggregate and gel material to replace natural aggregate and cement, reduces the exploitation and consumption of natural resources, and reduces carbon emissions and environmental pollution.

[0010] The above concrete composition is highly practical. Due to its high strength and good durability, it can be applied to complex construction conditions such as coal mine tunnels and floors, meeting the demand for high-performance concrete in coal mine construction without cracking, peeling and other phenomena.

[0011] The cost of concrete made from the concrete composition is reduced by more than 20% compared with traditional concrete made from natural aggregates and cement.

[0012] In some embodiments, the average particle size of the gangue crushed stone is 10 mm to 30 mm; and / or, the average particle size of the gangue coarse material is 5 mm to 10 mm; and / or, the average particle size of the gangue powder is <5 mm.

[0013] In some of the embodiments, the mass content of the gangue crushed stone is 35% to 45% of the gangue aggregate; and / or, the mass content of the gangue coarse material is 30% to 40% of the gangue aggregate; and / or, the mass content of the gangue stone powder is 25% to 35% of the gangue aggregate.

[0014] In some embodiments, the concrete composition satisfies at least one of the following conditions:

[0015] (1) The specific surface area of ​​the gel material is 420m² / kg to 450m² / kg;

[0016] (2) The mass content of the slag in the gel material is 50% to 80%, the mass content of the gypsum in the gel material is 8% to 20%, and the mass content of the carbide slag in the gel material is 10% to 30%;

[0017] (3) The gel material further comprises at least one of fly ash and steel slag; the fly ash accounts for 15% to 30% of the gel material by mass, the slag accounts for 35% to 70% of the gel material by mass, the steel slag accounts for 0% to 20% of the gel material by mass, the gypsum accounts for 5% to 8% of the gel material by mass, and the carbide slag accounts for 10% to 16% of the gel material by mass;

[0018] (4) The mass ratio of the gel material to the coal gangue aggregate is 1:4-4.5.

[0019] In some embodiments, the concrete composition satisfies at least one of the following conditions:

[0020] (1) The water reducer includes at least one of a naphthalene-based water reducer, a polycarboxylic acid-based water reducer, an aminosulfonic acid-based water reducer and an aliphatic-based water reducer;

[0021] (2) The water reducer is a polycarboxylate water reducer with a solid content of ≥40%, and the added amount of the polycarboxylate water reducer accounts for 0.1% to 0.3% of the mass of the concrete.

[0022] In some embodiments, the concrete composition further comprises at least one of an air entraining agent and an interface enhancer; the interface enhancer is an alkali metal salt, and the added amount of the interface enhancer accounts for 0.2% to 0.5% of the mass of the gel material.

[0023] In some embodiments, the concrete composition satisfies at least one of the following conditions:

[0024] (1) The slag comprises 39% to 40% by weight of silicon dioxide, 39% to 40% by weight of calcium oxide, 7% to 8% by weight of magnesium oxide, and 12% to 13% by weight of aluminum oxide;

[0025] (2) The specific surface area of ​​the slag is 400m² / kg to 450m² / kg;

[0026] (3) The gypsum includes at least one of power plant desulfurization gypsum, fluorite, phosphogypsum and titanium gypsum; the mass content of calcium sulfate in the gypsum is ≥ 80%;

[0027] (4) The main component of the carbide slag is calcium hydroxide, and the mass content of calcium hydroxide in the carbide slag is ≥85%;

[0028] (5) The specific surface area of ​​the carbide slag is ≥450m² / kg.

[0029] The second aspect of the present application provides a method for preparing concrete, using the concrete composition as described in the first aspect, and the preparation method comprises the following steps:

[0030] The gangue crushed stone, the gangue coarse material, the gangue powder, the gel material, the water reducing agent and water are mixed and solidified to obtain the concrete.

[0031] The third aspect of the present application provides a concrete prepared by the preparation method described in the second aspect.

[0032] A fourth aspect of the present application provides a concrete product, comprising the concrete described in the third aspect. DETAILED DESCRIPTION

[0033] For the convenience of understanding the present invention, the present invention will be described more fully below with reference to relevant embodiments. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0035] As a solid waste generated during coal mining and washing, coal gangue has a large stockpile volume and has become one of the biggest obstacles to the high-quality development of the coal industry. At the same time, in coal mine construction, tunnel lining, floor paving and various infrastructure construction are inseparable from concrete. Concrete for tunnel lining is required to have a certain strength and stability to support the surrounding rock pressure and ensure the safety of the tunnel. At the same time, due to the special environment of coal mines underground, concrete must be able to adapt to certain humidity and temperature changes, and must have good impermeability and durability to prevent groundwater infiltration and other damage to the structure. In addition, there is a shortage of silicate cement in some coal mining areas, and it is necessary to develop and utilize concrete prepared from local solid waste materials to meet low-cost construction needs and realize the reuse of solid waste resources. However, coal gangue contains a certain amount of impurities such as combustibles, clay minerals and sulfides, and the resulting concrete has performance problems such as low strength, high water absorption and poor slurry interface adhesion.

[0036] Based on this, an embodiment of the present application provides a concrete composition, which includes the following components: coal gangue aggregate, gel material and water reducer; the coal gangue aggregate includes coal gangue crushed stone, coal gangue coarse material and coal gangue stone powder, and the average particle size of the coal gangue coarse material is larger than the average particle size of the coal gangue stone powder and smaller than the average particle size of the coal gangue crushed stone; the gel material includes slag, gypsum and carbide slag.

[0037] The concrete composition of the present application adopts coal gangue of different grades as aggregate and is compounded with gel material and water reducing agent to make concrete. The various raw materials synergize to improve the strength, impermeability, interface adhesion, durability, workability and crack resistance of the concrete.

[0038] The three-grade design of gangue aggregate, namely gangue crushed stone, gangue coarse material and gangue stone powder, can optimize the density and strength of concrete; by adjusting the grading of gangue aggregate, the porosity of concrete can be reduced and the density and strength grade of concrete can be improved.

[0039] The fine particles in slag can fill the voids in concrete, and its active ingredients can react with hydration products to generate new hydration products, thereby improving the concrete's impermeability and durability. When slag-compounded gypsum and carbide slag are used together, the sulfate in the gypsum can stimulate the activity of the remaining solid waste raw materials in the gel material, allowing the solid waste materials to react with the hydration products more quickly, thereby improving the early strength of the clinker-free gelling system, and can regulate the setting time to make the setting process of concrete more reasonable, while also improving the concrete's later strength and microstructure density; when slag-compounded gypsum and carbide slag are used together, the carbide slag cooperates with the stimulating effect of gypsum, and the alkaline components in the carbide slag can react with the sulfate in the gypsum, further stimulating the activity of the remaining solid waste raw materials in the gel material, thereby further improving the strength and durability of the concrete.

[0040] The addition of water reducer can improve the working properties of concrete such as fluidity and pumpability, and can also enhance the strength and durability of concrete after hardening.

[0041] The concrete composition uses a gel material composed entirely of solid waste raw materials, omits cement, reduces the production cost of concrete, and realizes the resource utilization of solid waste. The concrete composition uses coal gangue aggregate and gel material to replace natural aggregate and cement, reduces the exploitation and consumption of natural resources, and reduces carbon emissions and environmental pollution.

[0042] The above concrete composition is highly practical. Due to its high strength and good durability, it can be applied to complex construction conditions such as coal mine tunnels and floors, meeting the demand for high-performance concrete in coal mine construction without cracking, peeling and other phenomena.

[0043] The cost of concrete made from the concrete composition is reduced by more than 20% compared with traditional concrete made from natural aggregates and cement.

[0044] In some embodiments, the average particle size of the gangue crushed stone is 10 mm to 30 mm; and / or, the average particle size of the gangue coarse material is 5 mm to 10 mm; and / or, the average particle size of the gangue powder is <5 mm.

[0045] In some embodiments, the average particle size of the gangue crushed stone is 10 mm to 30 mm, the average particle size of the gangue coarse material is 5 mm to 10 mm, and the average particle size of the gangue powder is <5 mm. According to the particle size distribution characteristics of the gangue aggregate, a three-graded design is adopted, and the gangue crushed stone with an average particle size of 10 mm to 30 mm, the gangue coarse material with an average particle size of 5 mm to 10 mm, and the gangue powder with an average particle size <5 mm are mixed in a certain proportion, which can optimize the density and strength of the concrete; by adjusting the gradation of the gangue aggregate, the porosity of the concrete can be reduced, and the density and strength grade of the concrete can be improved; the gradation and components of the gangue can be adjusted according to the different strength grades and working performance requirements of the concrete, and can meet the requirements of concrete with different strength grades such as C15~C30.

[0046] In some of the embodiments, the mass content of the gangue crushed stone in the gangue aggregate is 35% to 45%.

[0047] As an example, the mass content of gangue crushed stone in gangue aggregate can be 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44% and 45%, or it can be within the range consisting of any two of the above point values ​​as end values, preferably 35%~40%.

[0048] In some of the embodiments, the mass content of the gangue coarse material is 30% to 40% of the gangue aggregate.

[0049] As an example, the mass content of gangue coarse material in gangue aggregate can be 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39% and 40%, or it can be within the range consisting of any two of the above point values ​​as end values, preferably 30%~35%.

[0050] In some of the embodiments, the mass content of the gangue powder in the gangue aggregate is 25% to 35%.

[0051] As an example, the mass content of gangue powder in gangue aggregate can be 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34% and 35%, or it can be within the range consisting of any two of the above point values ​​as end values, preferably 28%~35%.

[0052] In some of the embodiments, the mass content of the gangue crushed stone is 35% to 45% of the gangue aggregate; and / or, the mass content of the gangue coarse material is 30% to 40% of the gangue aggregate; and / or, the mass content of the gangue stone powder is 25% to 35% of the gangue aggregate.

[0053] In some implementation methods, the mass content of the gangue crushed stone in the gangue aggregate is 35% to 45%, the mass content of the gangue coarse material in the gangue aggregate is 30% to 40%, and the mass content of the gangue powder in the gangue aggregate is 28% to 35%. Coal gangue crushed stone has a larger particle size. Large-size aggregate forms a skeleton structure in concrete, which can withstand a larger load, improve the strength and stability of concrete, and can reduce the amount of cement paste to improve the economy of concrete; coal gangue coarse material can be filled in the gaps of coal gangue crushed stone to further improve the density of the concrete structure, thereby improving the strength and durability of concrete; coal gangue powder can fill smaller gaps in the concrete structure, improve the workability of concrete, and further improve the density. At the same time, the coal gangue powder also participates in the hydration reaction to enhance the strength of concrete; the coal gangue aggregate obtained under this mass ratio of the three has excellent performance, and the obtained concrete has better comprehensive performance, with high strength and durability.

[0054] As an example, if the concrete strength grade requirement is high, it is necessary to appropriately increase the mass proportion of large-size coal gangue crushed stone to improve the skeleton effect of concrete. If the concrete strength needs to reach C30 level, the proportion of coal gangue crushed stone in the coal gangue aggregate can reach 45% wt.; and the site concrete requires better fluidity, and the proportion of coal gangue stone powder in the coal gangue aggregate can be increased to 35wt.%.

[0055] In some embodiments, the average particle size of the gangue crushed stone is 10 mm to 30 mm, the average particle size of the gangue coarse material is 5 mm to 10 mm, and the average particle size of the gangue powder is <5 mm; the mass content of the gangue crushed stone in the gangue aggregate is 35% to 45%, the mass content of the gangue coarse material in the gangue aggregate is 30% to 40%, and the mass content of the gangue powder in the gangue aggregate is 28% to 35%. The gangue crushed stone with an average particle size of 10 mm to 30 mm and accounting for 35% to 45% of the mass content of the gangue aggregate has a larger particle size. The large particle size aggregate forms a skeleton structure in the concrete, which can withstand a larger load and improve the strength and stability of the concrete. Coal gangue coarse material with an average particle size of 5 mm ~10 mm and a mass content of 30%~40% of the coal gangue aggregate can be filled in the gaps of coal gangue crushed stone, further improving the density of the concrete structure, thereby improving the strength and durability of the concrete. Coal gangue powder with an average particle size of <5 mm and a mass content of 28%~35% of the coal gangue aggregate can fill smaller gaps in the concrete structure, improve the workability of the concrete, and further improve the density. At the same time, the coal gangue powder also participates in the hydration reaction and enhances the strength of the concrete.

[0056] In some embodiments, the specific surface area of ​​the gel material is 420 m2 / kg to 450 m2 / kg. The fineness of the gel material under this specific surface area is appropriate, which is more conducive to the coordinated cooperation between the components to stimulate the activity, thereby improving the activity of the gel material.

[0057] In some embodiments, the slag accounts for 50% to 80% of the mass of the gel material, the gypsum accounts for 8% to 20% of the mass of the gel material, and the carbide slag accounts for 10% to 30% of the mass of the gel material.

[0058] Furthermore, the mass content of the gypsum in the gel material is preferably 8% to 10%.

[0059] Furthermore, the mass content of the carbide slag in the gel material is preferably 10% to 14%.

[0060] In some embodiments, the gel material further includes at least one of fly ash and steel slag. Steel slag includes but is not limited to high-temperature smelting slag. The addition of steel slag can increase the system's gelling activity, reduce the amount of slag used, and reduce costs. Moreover, steel slag can react with hydration products to generate new hydration products, thereby improving the strength and durability of concrete. The micro-aggregate effect and volcanic ash activity of fly ash can improve the working fluidity of concrete and improve the strength and durability of concrete. That is, the fine particles of fly ash can fill the voids in the gelling slurry to make the concrete structure more compact. The active ingredients in fly ash can react with hydration products to generate new hydration products, thereby improving the strength and durability of concrete.

[0061] In some embodiments, the fly ash accounts for 10% to 30% by weight of the gel material.

[0062] As an example, the mass content of fly ash in the gel material can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, and 30%, or it can be within the range consisting of any two of the above point values ​​as end values.

[0063] Furthermore, the fly ash accounts for 15% to 30% of the mass content of the gel material.

[0064] In some embodiments, the slag accounts for 35% to 70% by weight of the gel material.

[0065] As an example, the mass content of slag in the gel material can be 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69% and 70%, or it can be within the range formed by any two of the above point values ​​as end values.

[0066] In some embodiments, the mass content of steel slag in the gel material is 0-20%.

[0067] As an example, the mass content of steel slag in the gel material can be 0, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% and 20%, or it can be within the range consisting of any two of the above point values ​​as end values.

[0068] In some embodiments, the mass content of gypsum in the gel material is 5% to 8%.

[0069] As an example, the mass content of gypsum in the gel material may be 5%, 5.5%, 6%, 6.5%, 7%, 7.5% and 8%, or may be within a range consisting of any two of the above point values ​​as end values.

[0070] In some of the embodiments, the mass content of carbide slag in the gel material is 10% to 16%.

[0071] As an example, the mass content of carbide slag in the gel material can be 10%, 11%, 12%, 13%, 14%, 15% and 16%, or can be within the range consisting of any two of the above point values ​​as end values.

[0072] In some implementation methods, the mass content of the fly ash in the gel material is 15% to 30%, the mass content of the slag in the gel material is 35% to 70%, the mass content of the steel slag in the gel material is 0 to 20%, the mass content of the gypsum in the gel material is 5% to 8%, and the mass content of the carbide slag in the gel material is 10% to 16%. The gel material at this ratio is highly active, and the concrete made from this gel material has high strength and good interface adhesion. If the concrete strength requirement is high and the setting time requirement is short, slag and carbide slag are often used to reduce the amount of fly ash and steel slag.

[0073] In some of the embodiments, the mass ratio of the gel material to the coal gangue aggregate is 1:4-4.5.

[0074] In some embodiments, the water reducer includes at least one of a naphthalene water reducer, a polycarboxylic acid water reducer, an aminosulfonic acid water reducer, and an aliphatic water reducer. The water reducer improves the workability of concrete with coal gangue as aggregate, such as fluidity and pumpability, and the physical and mechanical properties after hardening, such as strength and durability.

[0075] In some embodiments, the water reducer is a polycarboxylate water reducer with a solid content of ≥40%, and the amount of the polycarboxylate water reducer added is 0.1% to 0.3% of the mass of the concrete. For low-strength concrete, the amount can be 0.1%, and for high-strength concrete or concrete with higher workability requirements, 0.3% can be added.

[0076] In some embodiments, the raw materials for preparing the concrete further include at least one of an air entraining agent and an interface enhancer. The air entraining agent can introduce tiny bubbles into the concrete, thereby improving the workability, frost resistance and durability of the concrete. The interface enhancer can form a bridging structure, fill the micropores on the surface of the gangue aggregate, and increase the strength of the interface transition zone between the gangue aggregate and the gel material slurry, thereby significantly improving the impermeability, freeze-thaw cycle resistance and strength of the concrete.

[0077] Furthermore, the amount of air entraining agent added is 0.2% to 0.5% of the mass of concrete.

[0078] In some embodiments, the interface enhancer includes at least one of an emulsion interface enhancer, a powder interface enhancer, a fiber interface enhancer, and a chemically active interface enhancer. Emulsion interface enhancers have good flexibility and adhesion, can adapt to the deformation of concrete, reduce stress concentration at the interface, and can improve the impermeability, freeze-thaw resistance, and durability of concrete. Powder interface enhancers can significantly improve the strength and durability of concrete, especially the early strength of concrete, and can also improve the workability of concrete and reduce bleeding. Fiber interface enhancers can greatly improve the tensile strength and crack resistance of concrete, and are particularly suitable for structures with high requirements for the tensile properties of concrete.

[0079] Furthermore, the emulsion-based interface enhancer may be a polymer emulsion.

[0080] Furthermore, the powder-based interface enhancer may be at least one of silica fume, microsilica powder and redispersible latex powder.

[0081] Furthermore, the fiber-based interface reinforcer may be at least one of carbon fiber and glass fiber.

[0082] Furthermore, the chemically active interface enhancer may be at least one of a silane coupling agent, a titanate coupling agent and an alkali metal salt interface enhancer.

[0083] Understandably, in the alkali metal salt interface enhancer, the alkali metal includes lithium, sodium, potassium, etc., and its salts can be carbonates, sulfates, nitrates, etc. As an example, the alkali metal salt interface enhancer can be one or more of sodium carbonate, sodium sulfate, sodium nitrate, lithium carbonate, lithium sulfate, potassium nitrate, potassium carbonate, potassium sulfate and potassium nitrate.

[0084] The interface enhancer is preferably a nano-silica sol interface enhancer, a polymer emulsion interface enhancer or an alkali metal salt interface enhancer. In view of the porous characteristics of coal gangue aggregate, a nano-silica sol interface enhancer or a polymer emulsion interface enhancer is introduced to form a nano-scale or micron-scale bridging structure during the concrete mixing process, fill the micropores on the surface of the aggregate, and enhance the interface transition zone between the aggregate and the cementitious material slurry, thereby significantly improving the concrete's impermeability, freeze-thaw cycle resistance and strength; the nano-silica sol interface enhancer and the polymer emulsion interface enhancer have good surface activity and filling properties, can fully contact with the surface of the coal gangue aggregate and fill the micropores, forming a stable bridging structure, thereby enhancing the interface bonding force. In view of the low surface strength of coal gangue aggregate, modified alkali metal salt interface enhancer is used. The modified alkali metal salt interface enhancer can react with calcium hydroxide in carbide slag. At the same time, coal gangue powder can also react with carbide slag. The two have a synergistic effect in the combined mechanism, which together improves the interface bonding strength between the slurry and the aggregate, thereby better improving the strength and durability of concrete with coal gangue as aggregate.

[0085] Furthermore, the added amount of the interface enhancer accounts for 0.2% to 0.5% of the mass of the gel material.

[0086] Furthermore, the interface enhancer is an alkali metal salt, and the addition amount of the interface enhancer accounts for 0.2% to 0.5% of the mass of the gel material. The concrete obtained under this condition has good comprehensiveness, excellent impermeability and strength.

[0087] Furthermore, the interface enhancer is one or two of alkali metal salt enhancers such as nano silica sol, sodium aluminate, sodium silicate, sodium carbonate and sodium chloride.

[0088] In some embodiments, the slag includes 39% to 40% by mass of silicon dioxide, 39% to 40% by mass of calcium oxide, 7% to 8% by mass of magnesium oxide, and 12% to 13% by mass of aluminum oxide.

[0089] In some embodiments, the specific surface area of ​​the slag is 400m² / kg to 450m² / kg.

[0090] Furthermore, the slag adopts S95 grade blast furnace slag powder.

[0091] In some embodiments, the gypsum is industrial by-product gypsum, and the gypsum includes at least one of power plant desulfurization gypsum, fluorite, phosphogypsum and titanium gypsum. The use of industrial by-product gypsum can further reduce the cost of concrete. The amount of gypsum can be adjusted according to the volume stability, that is, the expansion and contraction rate.

[0092] In some of the embodiments, the mass content of calcium sulfate in the gypsum is ≥80%.

[0093] In some of the embodiments, the main component of the carbide slag is calcium hydroxide, and the mass content of calcium hydroxide in the carbide slag is ≥85%.

[0094] In some of the embodiments, carbide slag is derived from the process of producing acetylene and polyvinyl chloride by the carbide method. The main component of the carbide slag is calcium hydroxide, with a mass content of 85% to 95%. In addition, it also contains a small amount of impurities such as silicon oxide, aluminum oxide, iron oxide, magnesium oxide and sulfide.

[0095] In some embodiments, the specific surface area of ​​the carbide slag is ≥450m² / kg.

[0096] The second aspect of the present application provides a method for preparing concrete, using the concrete composition as described in the first aspect, and the preparation method comprises the following steps:

[0097] The gangue crushed stone, the gangue coarse material, the gangue powder, the gel material, the water reducing agent and water are mixed and solidified to obtain the concrete.

[0098] In some embodiments, the gangue crushed stone, the gangue coarse material and the gangue powder are obtained by crushing and screening the gangue.

[0099] In some of the implementation methods, when crushing and screening the gangue, the collected gangue is initially crushed by a jaw crusher, and then further crushed to a desired particle size range by an impact crusher; then a vibrating screening machine is used for screening to separate three types of aggregates, namely, gangue crushed stone (10-30 mm), gangue coarse material (5-10 mm), and gangue stone powder (<5 mm), and store them separately.

[0100] In some of the embodiments, before grinding solid waste raw materials such as slag, gypsum and carbide slag, solid waste raw materials with high water content, such as industrial by-product gypsum and carbide slag, are first dried to remove excess moisture. The moisture content after drying does not exceed 5% to ensure the grinding effect.

[0101] Furthermore, the dried solid waste raw materials are ground using equipment such as a ball mill or a vertical mill to ensure that the specific surface area of ​​the ground material reaches 420m² / kg~450m² / kg, so as to increase the activity of the solid waste raw materials in concrete.

[0102] In some of the embodiments, the ground solid waste raw materials are mixed according to the following mass ratio: fly ash 15%~30%, slag 35%~70%, steel slag 0~20%, industrial by-product gypsum 5%~8%, and carbide slag 10%~16% to obtain a gel material.

[0103] In some of the implementation methods, gangue crushed stone, gangue coarse material, gangue powder, gel material, water, water reducer, air entraining agent and interface enhancer are sequentially added into a mixer, and are fully stirred in the order of dry mixing first and then wet mixing until the materials are evenly mixed, and the mixing time is 38s to 45s to make concrete. The stirred concrete is molded and compacted using equipment such as a vibrating table or a vibrating rod.

[0104] In some of the embodiments, pouring and vibrating are performed during the concrete construction process: the formed concrete is transported to the construction site for pouring, and vibrated using a suitable vibrating tool to remove bubbles and excess water in the concrete and improve the density and strength of the concrete.

[0105] In some implementation methods, the concrete after construction is cured: after the concrete is poured, it is cured in time, including moisture retention and heat preservation. Plastic film can be used to prevent the moisture on the concrete surface from evaporating too quickly. According to the ambient temperature and humidity conditions, the appropriate curing time and method are determined. During this period, the surface condition of the concrete needs to be checked regularly and moisture needs to be added in time.

[0106] Furthermore, the curing time is 7 to 28 days.

[0107] The third aspect of the present application provides a concrete prepared by the preparation method described in the second aspect.

[0108] The fourth aspect of the present application provides a concrete product, comprising the concrete described in the third aspect. The concrete product includes but is not limited to concrete hanging panels, concrete floors, concrete bricks, concrete pipes, pavements, bridge foundations, and the like.

[0109] The following are specific embodiments.

[0110] Example 1

[0111] The concrete preparation process of Example 1 is as follows:

[0112] Coal Gangue Aggregate Processing

[0113] The gangue aggregate is crushed and sieved by a jaw crusher and an impact crusher to obtain gangue crushed stone with an average particle size of 10 mm to 30 mm, gangue coarse material with an average particle size of 5 mm to 10 mm, and stone powder with an average particle size of less than 5 mm; the gangue crushed stone accounts for 35% of the mass of the gangue aggregate, the gangue coarse material accounts for 30% of the mass of the gangue aggregate, and the gangue stone powder accounts for 35% of the mass of the gangue aggregate to obtain the gangue aggregate.

[0114] Solid waste material treatment

[0115] After drying the industrial by-product gypsum and carbide slag, they are ground with a ball mill until the specific surface area reaches more than 450m² / kg. The fly ash is secondary ash, and the mineral powder is commercially available S95 slag powder. The gel material is obtained by mixing the fly ash 20wt.%, slag powder 48wt.%, steel slag 12wt.%, industrial by-product gypsum 8wt.%, and carbide slag 12wt.%.

[0116] Add water reducing agent, air entraining agent and interface enhancer

[0117] Polycarboxylate water reducer is used, the solid content of water reducer is not less than 40wt.%, and the dosage accounts for 0.1wt.% of the mass ratio of concrete. The dosage of air entraining agent accounts for 0.2wt.% of the mass ratio of concrete. Sodium aluminate (NaAlO2) is used as interface enhancer, and sodium aluminate accounts for 0.2wt.% of the total amount of cementitious materials.

[0118] Concrete production and preparation

[0119] Add the prepared gangue aggregate, gel material, water, water reducing agent, air entraining agent and interface enhancer into the mixer in sequence, and mix them thoroughly in the order of dry mixing first and then wet mixing until the materials are uniform. The mixing time is 38 to 45 seconds, and then the mixed concrete is cured and formed.

[0120] Concrete construction maintenance

[0121] After the concrete is poured, it is cured for 28 days.

[0122] Example 2

[0123] Example 2 is basically the same as Example 1, except that: in the gangue aggregate, gangue crushed stone accounts for 40 wt.%, gangue coarse material accounts for 35 wt.%, and gangue stone powder accounts for 25 wt.%; in the gel material, fly ash 15wt.%, slag 62wt.%, steel slag 5wt.%, industrial by-product gypsum 6wt.%, and carbide slag 12wt.%;

[0124] The content of polycarboxylic acid water-reducing agent accounts for 0.2wt.% of concrete; the content of air-entraining agent accounts for 0.3wt.% of concrete; and the content of interface enhancer accounts for 0.3wt.% of gel material.

[0125] Example 3

[0126] Example 3 is basically the same as Example 2, except that: in the gel material, fly ash is 10wt.%, slag is 70wt.%, steel slag is 0wt.%, industrial by-product gypsum is 5wt.%, and carbide slag is 15wt.%.

[0127] Example 4

[0128] Example 4 is basically the same as Example 1, except that among the gangue aggregate, gangue crushed stone accounts for 60wt.%, gangue coarse material accounts for 20wt.%, and gangue powder accounts for 20wt.%.

[0129] Example 5

[0130] Implementation 5 is substantially the same as Implementation 1, except that the interface enhancer is omitted.

[0131] Comparative Example 1

[0132] Comparative Example 1 is substantially the same as Example 1, except that the total mass of the gangue coarse material and the gangue powder is replaced by an equal mass of gangue crushed stone.

[0133] Comparative Example 2

[0134] Comparative Example 2 is substantially the same as Example 1, except that an equal mass of fly ash is used to replace slag.

[0135] Comparative Example 3

[0136] Comparative Example 3 is substantially the same as Example 1, except that an equal amount of fly ash is used to replace gypsum.

[0137] Comparative Example 4

[0138] Comparative Example 4 is substantially the same as Example 1, except that an equal mass of fly ash is used to replace carbide slag.

[0139] The concrete prepared in Examples 1 to 5 and Comparative Examples 1 to 4 was tested for strength (MPa), impermeability grade, collapse and frost resistance. The test results are shown in Table 1 below.

[0140] Table 1

[0141]

[0142] It can be seen from the data in Table 1 above that by using three-graded coal gangue as aggregate and compounding it with gel material and water reducer to make concrete, the strength, impermeability and durability of concrete are improved through the synergistic effect between various raw materials.

[0143] By comparing the data of Examples 1 to 5 and Comparative Examples 1 to 4, it can be seen that omitting the three-level gradation of coal gangue in the present application, or omitting any component of slag, gypsum and carbide slag in the gel material cannot achieve the technical effect of the present application.

[0144] By comparing the data of Examples 1-2 and 3, it can be seen that when the fly ash accounts for 15%-30% of the mass of the gel material, the slag accounts for 35%-70% of the mass of the gel material, the steel slag accounts for 0-20% of the mass of the gel material, the gypsum accounts for 5%-8% of the mass of the gel material, and the carbide slag accounts for 10%-16% of the mass of the gel material, the obtained concrete performance is better.

[0145] By comparing the data of Examples 1-2 with that of Example 4, it can be seen that in the grading of gangue aggregate, when gangue crushed stone accounts for 35%-45% of the mass of gangue aggregate, gangue coarse material accounts for 30%-40% of the mass of gangue aggregate, and gangue stone powder accounts for 25%-35% of the mass of gangue aggregate, the obtained concrete performance is better.

[0146] By comparing the data of Examples 1 to 4 with that of Example 5, it can be seen that adding an interface enhancer can increase the strength and impermeability of concrete.

[0147] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0148] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A concrete composition, characterized in that: The concrete composition comprises the following components: coal gangue aggregate, gel material and water reducing agent; the coal gangue aggregate comprises coal gangue crushed stone, coal gangue coarse material and coal gangue stone powder, the average particle size of the coal gangue coarse material is larger than the average particle size of the coal gangue stone powder and smaller than the average particle size of the coal gangue crushed stone; the gel material comprises slag, gypsum and carbide slag.

2. The concrete composition according to claim 1, characterized in that The average particle size of the gangue crushed stone is 10 mm to 30 mm; and / or, the average particle size of the gangue coarse material is 5 mm to 10 mm; and / or, the average particle size of the gangue powder is <5 mm.

3. The concrete composition according to claim 1, characterized in that The mass content of the gangue crushed stone in the gangue aggregate is 35% to 45%; and / or the mass content of the gangue coarse material in the gangue aggregate is 30% to 40%; and / or the mass content of the gangue stone powder in the gangue aggregate is 25% to 35%.

4. The concrete composition according to claim 1, characterized in that The concrete composition satisfies at least one of the following conditions: (1) The specific surface area of ​​the gel material is 420m² / kg to 450m² / kg; (2) The mass content of the slag in the gel material is 50% to 80%, the mass content of the gypsum in the gel material is 8% to 20%, and the mass content of the carbide slag in the gel material is 10% to 30%; (3) The gel material further comprises at least one of fly ash and steel slag; the fly ash accounts for 15% to 30% of the gel material by mass, the slag accounts for 35% to 70% of the gel material by mass, the steel slag accounts for 0% to 20% of the gel material by mass, the gypsum accounts for 5% to 8% of the gel material by mass, and the carbide slag accounts for 10% to 16% of the gel material by mass; (4) The mass ratio of the gel material to the coal gangue aggregate is 1:4-4.

5.

5. The concrete composition according to any one of claims 1 to 4, characterized in that The concrete composition satisfies at least one of the following conditions: (1) The water reducer includes at least one of a naphthalene-based water reducer, a polycarboxylic acid-based water reducer, an aminosulfonic acid-based water reducer and an aliphatic-based water reducer; (2) The water reducer is a polycarboxylate water reducer with a solid content of ≥40%, and the added amount of the polycarboxylate water reducer accounts for 0.1% to 0.3% of the mass of the concrete.

6. The concrete composition according to any one of claims 1 to 4, characterized in that The concrete composition further comprises at least one of an air entraining agent and an interface enhancer; the interface enhancer is an alkali metal salt, and the addition amount of the interface enhancer accounts for 0.2% to 0.5% of the mass of the gel material.

7. The concrete composition according to any one of claims 1 to 4, characterized in that The concrete composition satisfies at least one of the following conditions: (1) The slag comprises 39% to 40% by weight of silicon dioxide, 39% to 40% by weight of calcium oxide, 7% to 8% by weight of magnesium oxide, and 12% to 13% by weight of aluminum oxide; (2) The specific surface area of ​​the slag is 400m² / kg to 450m² / kg; (3) The gypsum includes at least one of power plant desulfurization gypsum, fluorite, phosphogypsum and titanium gypsum; the mass content of calcium sulfate in the gypsum is ≥ 80%; (4) The main component of the carbide slag is calcium hydroxide, and the mass content of calcium hydroxide in the carbide slag is ≥85%; (5) The specific surface area of ​​the carbide slag is ≥450m² / kg.

8. A method for preparing concrete, characterized in that: Using the concrete composition according to any one of claims 1 to 7, the preparation method comprises the following steps: The gangue crushed stone, the gangue coarse material, the gangue powder, the gel material, the water reducing agent and water are mixed and solidified to obtain the concrete.

9. A concrete, characterized in that: The method according to claim 8 is used to prepare the product.

10. A concrete product, characterized in that: Comprising the concrete according to claim 9.

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