Composite cementing material as well as preparation method and application thereof

Abstract

A composite cementing material relates to the technical field of building materials and comprises the following components in parts by weight: 150-600 parts of industrial byproduct gypsum, 300-700 parts of superfine slag powder, 75-190 parts of an alkali activator, 10-50 parts of a reinforcing agent, 0.5-1 part of a polycarboxylate superplasticizer and 2 parts of a curing agent. The invention also provides a preparation method of the composite cementing material, which comprises the following steps: S1, mixing the industrial byproduct gypsum, the superfine slag powder, the alkaline activator, the reinforcing agent, the polycarboxylic acid water reducer and the curing agent in proportion, and uniformly stirring to obtain the composite cementing material; the invention also provides application of the composite cementing material in building material products.

Description

Technical Field

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

[0002] Construction waste refers to solid waste generated during the construction, maintenance and demolition of buildings, including waste concrete blocks, waste bricks, asphalt concrete blocks, mortar and concrete scattered during the construction process, broken bricks, metal, bamboo and wood, waste generated by decoration and renovation, various packaging materials and other waste.

[0003] At present, the amount of construction waste in my country has accounted for 40% to 50% of the total urban waste, and most of the construction waste is disposed of in the form of open-air stacking or landfill, which consumes a lot of land and also buries great safety hazards to people's living environment. Therefore, recycling construction waste and turning waste into treasure is the best way to solve construction waste, and it is also an effective way to save resources and protect the existing fragile ecological environment; and in today's construction industry, cement is still very common and widely used, but the production and use of a large amount of cement will increase energy consumption and carbon dioxide emissions, causing pollution and damage to the ecological environment.

[0004] Therefore, in order to solve the above problems, construction waste is generally used to prepare gel materials to replace cement materials in order to reduce energy consumption and carbon dioxide emissions; such as the Chinese invention patent CN101905954B, which discloses a gel material made of construction waste and a preparation method thereof, but the mechanical properties of the gel material prepared by this patent are still not excellent enough. Summary of the invention

[0005] In view of the deficiencies in the prior art, the invention provides a composite gelling material and a preparation method and application thereof, which solves the problem that the performance of the gelling material in the prior art is not good enough.

[0006] A composite cementitious material comprises, by weight, 150-600 parts of industrial by-product gypsum, 300-700 parts of slag powder, 75-190 parts of alkaline activator, 10-50 parts of reinforcing agent, 0.5-1 part of polycarboxylic acid water reducer and 2 parts of curing agent.

[0007] Preferably, the mass fraction of calcium sulfate in the industrial by-product gypsum is greater than 80%.

[0008] Preferably, the industrial by-product gypsum is phosphogypsum or desulfurized gypsum.

[0009] Preferably, the slag powder is selected from S95 grade and has a specific surface area greater than 350m 2 / kg.

[0010] Preferably, the alkaline activator is cement and carbide slag or cement and lime.

[0011] Preferably, the reinforcing agent is silica fume, and the specific surface area of ​​the silica fume is 12000m 2 / kg, and the 28-day activity index of silica fume is greater than 105%.

[0012] The present invention also provides a method for preparing a composite gelling material, which is characterized by comprising the following steps:

[0013] S1. Mix industrial by-product gypsum, slag powder, alkaline activator, reinforcing agent, polycarboxylic acid water reducer and curing agent in proportion, stir evenly to obtain a composite cementitious material.

[0014] Preferably, the industrial by-product gypsum in step S1 needs to be washed with water before mixing.

[0015] The invention also provides an application of the composite cementitious material in building material products.

[0016] Compared with the prior art, the invention has the following beneficial effects:

[0017] 1. In the case of a large amount of industrial by-product gypsum, the present invention uses cement and carbide slag or cement and lime as alkaline activators to disintegrate the active substances in the slag powder in an alkaline environment, wherein the aluminum substance in the active substance reacts with calcium sulfate to generate hydrated calcium sulfoaluminate gel, which eventually crystallizes to generate ettringite (AFt); at the same time, the slag powder itself is hydrated to generate hydrated calcium silicate gel under the action of the alkaline activator.

[0018] 2. During the entire hydration process, silica fume, as a functional reinforcing material with high activity and high specific surface area, induces the activity of slag powder at an early stage and participates in the hydration reaction, effectively improving the early strength of the entire material system. At the same time, the ultra-fine particle size of incompletely reacted silica fume is used as a filler to fill the tiny micropores inside the structure, increasing the density of the hardened composite cementitious material.

[0019] Cement and carbide slag or cement and lime are used as dual-excitation materials in this system, which maintains a high alkalinity environment for the entire slurry, and promotes the self-hydration reaction of slag powder and the reaction with calcium sulfate to be continuous, sufficient and complete. At the same time, cement itself participates in the hydration reaction in the early stage to generate calcium silicate gel, which has a great promoting and strengthening effect on the entire slurry system.

[0020] The polycarboxylate water reducer is used as a polymer stimulator in this formula, which makes the cement participate in the hydration reaction and stimulates the hydration reaction of the mineral powder more fully and completely, while reducing the water demand of the composite cementitious material and making the hardened body structure more compact.

[0021] The curing agent makes the structure of the overall material more compact, forms a spatial network cross-linked structure inside the material, and effectively fills the tiny pores in the structure, thereby improving the strength of the hardened body and also improving the water resistance.

[0022] 3. The present invention uses industrial by-product gypsum, slag powder, silica fume, carbide slag or lime and other solid wastes, and mixes them with a small amount of cement to form a composite cementitious material, which has similar or even better performance than cement. In some application scenarios, it can replace cement, thereby reducing energy consumption and carbon dioxide emissions to a certain extent. In addition, the use of solid waste materials as raw materials greatly reduces product costs. More importantly, it allows the recycling of renewable resources, protects the environment and ecology, reduces the mining of cement limestone, and has the effects of energy saving, emission reduction, greenness and environmental protection.

[0023] Other advantages, objectives and features of the invention will be reflected in part through the following description, and in part will be understood by those skilled in the art through study and practice of the invention. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, purpose and function of the invention clearer and easier to understand, the invention is further explained below in conjunction with specific implementation methods:

[0025] Example 1

[0026] Preparation of composite cementitious materials:

[0027] S1. In parts by weight, take 600 parts of original phosphogypsum, 300 parts of slag powder, 50 parts of cement, 25 parts of carbide slag, 25 parts of silica fume, 1 part of polycarboxylate water reducer and 2 parts of curing agent, mix and stir to obtain a composite cementitious material;

[0028] Preparation of solid bricks, pavement turns and curbstones:

[0029] S2. Granulated electric furnace phosphorus slag, sand and fine stone were mixed in a mass ratio of 1:0.2:0.2 and stirred to obtain graded aggregate;

[0030] S3. The composite cementitious material prepared in S1 and the graded aggregate prepared in S2 are mixed in a mass ratio of 1:1, water is added and stirred evenly, and then made into solid standard bricks, pavement turns and curbstones respectively.

[0031] Example 2

[0032] Preparation of composite cementitious materials:

[0033] S1. In parts by weight, take 300 parts of desulfurized gypsum, 500 parts of slag powder, 100 parts of cement, 50 parts of lime, 50 parts of silica fume, 0.5 parts of polycarboxylate water reducer and 2 parts of curing agent, mix and stir to obtain a composite cementitious material;

[0034] Preparation of solid bricks, pavement turns and curbstones:

[0035] S2. Granulated electric furnace phosphorus slag, sand and fine stone were mixed in a mass ratio of 1:0.3:0.3 and stirred to obtain graded aggregate;

[0036] S3. The composite cementitious material prepared in S1 and the graded aggregate prepared in S2 are mixed in a mass ratio of 1:1.1, water is added and stirred evenly, and then made into solid standard bricks, pavement turns and curbstones respectively.

[0037] Example 3

[0038] Preparation of composite cementitious materials:

[0039] S1. In parts by weight, take 450 parts of desulfurized gypsum, 350 parts of slag powder, 175 parts of cement, 15 parts of carbide slag, 10 parts of silica fume, 0.7 parts of polycarboxylate water reducer and 2 parts of curing agent, mix and stir to obtain a composite cementitious material;

[0040] Preparation of solid bricks, pavement turns and curbstones:

[0041] S2. Granulated electric furnace phosphorus slag, sand and fine stone are mixed in a mass ratio of 1:0.2:0.3 and stirred to obtain graded aggregate;

[0042] S3. The composite cementitious material prepared in S1 and the graded aggregate prepared in S2 are mixed in a mass ratio of 1:1.4, water is added and stirred evenly, and then made into solid standard bricks, pavement turns and curbstones respectively.

[0043] Example 4

[0044] Preparation of composite cementitious materials:

[0045] S1. In parts by weight, take 500 parts of original phosphogypsum, 320 parts of slag powder, 100 parts of cement, 40 parts of lime, 40 parts of silica fume, 0.6 parts of polycarboxylate water reducer and 2 parts of curing agent, mix and stir to obtain a composite cementitious material;

[0046] Preparation of solid bricks, pavement turns and curbstones:

[0047] S2. Granulated electric furnace phosphorus slag, sand and fine stone were mixed in a mass ratio of 1:0.3:0.2 and stirred to obtain graded aggregate;

[0048] S3. The composite cementitious material prepared in S1 and the graded aggregate prepared in S2 are mixed in a mass ratio of 1:1.3, water is added and stirred evenly, and then made into solid standard bricks, pavement turns and curbstones respectively.

[0049] Example 5

[0050] Preparation of composite cementitious materials:

[0051] S1. In parts by weight, take 150 parts of original phosphogypsum, 700 parts of slag powder, 50 parts of cement, 50 parts of lime, 50 parts of silica fume, 0.9 parts of polycarboxylate water reducer and 2 parts of curing agent, mix and stir to obtain a composite cementitious material;

[0052] Preparation of solid bricks, pavement turns and curbstones:

[0053] S2. Granulated electric furnace phosphorus slag, sand and fine stone were mixed in a mass ratio of 1:0.25:0.25 and stirred to obtain graded aggregate;

[0054] S3. The composite cementitious material prepared in S1 and the graded aggregate prepared in S2 are mixed in a mass ratio of 1:1.5, water is added and stirred evenly, and then made into solid standard bricks, pavement turns and curbstones respectively.

[0055] Wherein, the particle size of the granulated electric furnace phosphorus slag in the above embodiments 1-5 is 1 to 20 mm.

[0056] Furthermore, in step S3 of embodiments 1-5, when preparing solid standard bricks, pavement wheels and curbstones, the amount of water added is 10-20% of the total mass of the composite cementitious material and the graded aggregate.

[0057] The three products of solid standard bricks, pavement turn and curbstone prepared in the above Examples 1-5 were cured under standard curing conditions, and the mechanical properties data of the three products measured at different time periods are shown in Tables 1-3.

[0058] 1. Solid standard brick:

[0059]

[0060]

[0061] Table 1 Mechanical properties of solid standard bricks prepared in various embodiments Table 2 Pavement bricks:

[0062]

[0063] Table 2 Mechanical properties of pavement bricks prepared in various embodiments Table 3 Kerbstones:

[0064]

[0065] Table 3 Mechanical properties data of pavement bricks prepared in various embodiments

[0066] The average density of the solid standard bricks prepared by the present invention is 1912 kg / m 3 The average density of pavement bricks is 2232kg / m 3 The average density of the curb is 2116kg / m 3 .

[0067] It is measured that the average maximum water absorption rate of the solid standard bricks prepared by the present invention is 9.7%, the average maximum water absorption rate of the road bricks is 5.3%, and the average maximum water absorption rate of the curbstones is 4.6%.

[0068] The drying shrinkage of the solid standard brick prepared by the present invention is measured to be 0.03%.

[0069] The relative moisture content of the solid standard brick prepared by the present invention was measured to be 28% (average water absorption rate of 5 bricks).

[0070] The frost resistance of the solid standard brick prepared by the present invention was measured: the mass loss was 3.3%, and the strength loss was 22.3%; the frost resistance of the road brick: the strength loss rate was 18.1%; the frost resistance of the curb stone: the mass loss rate was 2.8%.

[0071] The carbonization coefficient of the solid standard brick prepared by the present invention is measured to be 82.6%.

[0072] The softening coefficient of the solid standard brick prepared by the present invention is measured to be 87.1%.

[0073] In summary, the performance of the composite cementitious material meets the requirements of relevant standard indicators and can perfectly replace cement.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the invention rather than to limit it. Although the invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the invention, which should be included in the scope of the claims of the invention.

Claims

1. A composite cementitious material, characterized in that: Calculated by weight, it includes 150-600 parts of industrial by-product gypsum, 300-700 parts of slag powder, 75-190 parts of alkaline activator, 10-50 parts of reinforcing agent, 0.5-1 part of polycarboxylic acid water reducer and 2 parts of curing agent.

2. A composite cementitious material according to claim 1, characterized in that: The mass fraction of calcium sulfate in the industrial by-product gypsum is greater than 80%.

3. A composite cementitious material according to claim 1, characterized in that: The industrial by-product gypsum is phosphogypsum or desulfurized gypsum.

4. A composite cementitious material according to claim 1, characterized in that: The slag powder is selected from S95 grade and has a specific surface area greater than 350m 2 / kg.

5. A composite cementitious material according to claim 1, characterized in that: The alkaline activator is cement and carbide slag or cement and lime.

6. A composite cementitious material according to claim 1, characterized in that: The reinforcing agent is silica fume, and the specific surface area of ​​the silica fume is 12000m 2 / kg, and the 28-day activity index of silica fume is greater than 105%.

7. A method for preparing a composite cementitious material according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Mix industrial by-product gypsum, slag powder, alkaline activator, reinforcing agent, polycarboxylic acid water reducer and curing agent in proportion, stir evenly to obtain a composite cementitious material.

8. The method for preparing a composite gelling material according to claim 7, characterized in that: In step S1, the industrial by-product gypsum needs to be washed with water before mixing.

9. Use of a composite cementitious material according to any one of claims 1 to 6 in building material products.

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