CN103449838B - Foamed cement board taking foamed cement board leftovers as regenerated aggregates - Google Patents

Abstract

The invention relates to a foamed cement board which uses leftovers of the foamed cement board as recycled aggregates. It is composed of ordinary Portland cement, fly ash, recycled aggregate, hydrogen peroxide, zinc stearate, bentonite, early strength agent, water reducing agent and polypropylene fiber. The recycled aggregate in the present invention is processed by crushing and sieving the leftovers of the foamed cement board. Dry mix ordinary Portland cement, fly ash, recycled aggregate, zinc stearate, bentonite, early strength agent, water reducer and polypropylene fiber according to the mixing ratio, then add water and stir, and finally add hydrogen peroxide for chemical Foaming, the foamed cement board is made after hydration and hardening. The invention solves the problems of construction waste disposal and ecological environment pollution caused by it, and at the same time replaces natural aggregates with recycled aggregates processed from leftovers of foamed cement boards, and also alleviates the problems caused by the increasing scarcity of natural aggregates. production pressure. The foamed cement board prepared by the invention has low cost, convenient construction and good thermal insulation performance, and can be used for external thermal insulation of exterior walls of building construction.

Description

A foamed cement board using foamed cement board scraps as recycled aggregates

technical field

The invention belongs to the technical field of building materials, and in particular relates to a foamed cement board which uses leftovers of the foamed cement board as recycled aggregates.

Background technique

Foamed cement board has the advantages of small dry apparent density, low thermal conductivity, low cost and convenient construction, and has been widely produced and applied. However, in the production process, there are shortcomings such as unstable foaming and difficult control of molding, resulting in uneven corners, cutting around the product, and the cut off waste becomes industrial waste. According to statistics, the amount of leftovers accounts for about 5% of the production of foamed cement board production plants. Due to the lack of recycling technology, the factory simply stacks them and finally transports them to the garbage dump for disposal, which not only occupies a large area of land, but also causes environmental pollution to a certain extent. At present, the annual output of such waste is quite high. If it cannot be recycled, it will not only be a waste of resources, but also bring a great burden to the environment.

The foamed cement board prepared by the present invention mainly uses ordinary Portland cement and fly ash as the cementing material, the fine aggregate obtained after processing the leftovers of the foamed cement board as the recycled aggregate, and hydrogen peroxide as the foaming agent. The construction is convenient and the thermal insulation performance is good, which can meet the external thermal insulation requirements of building buildings in different regions, and has excellent economic and environmental benefits.

Contents of the invention

The object of the present invention is to provide a foamed cement board with convenient construction, high strength and good thermal insulation performance, which uses foamed cement board leftovers as recycled aggregates.

The foamed cement board proposed by the present invention uses the leftovers of foamed cement boards as recycled aggregates, uses ordinary Portland cement and fly ash as cementing materials, uses the leftovers of foamed cement boards as recycled aggregates, and uses hydrogen peroxide It is a foaming agent, supplemented by various admixtures. The foamed cement board that the present invention proposes uses the leftovers of the foamed cement board as the recycled aggregate, which is composed of ordinary Portland cement, fly ash, recycled aggregate, hydrogen peroxide, zinc stearate, bentonite, early strength agent, Composed of water agent and polypropylene fiber, the weight ratio of each component is:

Ordinary Portland cement 100

Fly ash 5-30

Recycled aggregate 20-50

Hydrogen peroxide 4-10

Zinc stearate 1-10

Bentonite 1-15

Early strength agent 0.5-4

Water reducing agent 0.5-5

Polypropylene fiber 1-10.

The preferred weight ratio of each component is:

Ordinary Portland cement 100

Fly ash 10-20

Recycled aggregates 25-45

Hydrogen peroxide 5-8

Zinc stearate 2-6

Bentonite 3-10

Early strength agent 1-3

Water reducer 1-3

Polypropylene fiber 2-5.

In the present invention, the ordinary Portland cement is one of grade 42.5 or grade 52.5 ordinary Portland cement.

In the present invention, the fly ash is High-grade high-calcium fly ash, its free calcium oxide content is ≤3.0%, and its loss on ignition is ≤5.0%.

In the present invention, the recycled aggregate is processed by crushing and sieving foamed cement board leftovers, with a maximum particle size of 2.5 mm, a bulk density of (300-800) kg/m ³ , and a porosity of 13% -25%. Wherein the weight percentage of each particle size range: 9.5% for diameters of 1.25mm-2.5mm; 65.4% for diameters of 0.16mm-1.25mm; 25.1% for diameters smaller than 0.16mm.

In the present invention, the mass concentration of the hydrogen peroxide is 30%.

In the present invention, the zinc stearate is a white powder, chemically pure, with a zinc oxide content of 13.5%-15.5%.

In the present invention, the bentonite is sodium bentonite.

In the present invention, the early strengthening agent is one of sulfate or metaaluminate.

In the present invention, the water reducer is a sulfamate-based water reducer.

Among the present invention, described polypropylene fiber length is 3mm-9mm.

The preparation method of the foamed cement board that the present invention proposes is the foamed cement board leftovers of foamed cement board as recycled aggregate, and concrete steps are as follows:

(1) Break the leftovers of the foamed cement board, and pass through the sieves of 2.5mm, 1.25mm, and 0.16mm in turn to obtain three kinds of particle sizes ranging from 1.25 mm to 2.5mm, 0.16mm to 1.25mm, and less than 0.16mm. recycled aggregate;

(2) Prepare recycled aggregates according to the weight percentage of each particle size range: 9.5% for 1.25mm-2.5mm; 65.4% for 0.16mm-1.25mm; 25.1% for less than 0.16mm;

(3) Weigh the prepared recycled aggregate, ordinary Portland cement, fly ash, zinc stearate, bentonite, early strength agent, water reducing agent and polypropylene fiber prepared in step (2) according to the weight ratio, Add water and stir evenly, then add hydrogen peroxide and stir for 20 seconds, pour it into a mold for molding, demould after 1 day, and cut according to the required specifications to obtain the desired product.

In the present invention, cement is used as the main gelling component, and fly ash is used as an admixture to form a composite gelling system together with cement. High-calcium fly ash usually refers to a fly ash with a high CaO content discharged from thermal power plants using lignite and sub-bituminous coal as fuel. It is a kind of fly ash that contains a certain amount of hydraulic crystal minerals and potential active substances. s material. the

In the present invention, hydrogen peroxide is used as a foaming agent, because there are a small amount of metal ions in the cement slurry, such as Fe ³⁺ and Cu ²⁺ , and in the presence of these metal ions, hydrogen peroxide will undergo its own redox reaction, that is, disproportionation reaction , The reaction releases gas. When the gas generation rate of hydrogen peroxide and the hardening rate of the slurry are well matched, the slurry is hardened to form a porous structure. Therefore, the foamed cement board has excellent properties such as light weight, high strength and low thermal conductivity.

In the present invention, as a foam stabilizer, zinc stearate can improve the viscosity and stability of the foam, reduce the fluidity of the foam, and prolong the half-life of the foam.

In the present invention, the bentonite increases the viscosity of the cement slurry, which is beneficial to the stability of the foam, and can obviously improve the workability of the slurry, making it easy to form. The early strength agent promotes the setting and hardening of the cement paste, improves the early strength, makes the hardening rate of the paste better match the gas release rate, and prevents the phenomenon of mold collapse. The water reducer can improve the workability of the slurry, or reduce the water consumption while maintaining the same fluidity, which can obviously improve the strength of the slurry after hardening.

In the present invention, the polypropylene fiber is used as the reinforcing fiber, which can effectively improve the crack resistance, frost resistance and impermeability of the foamed cement board. Polypropylene fibers can absorb impact energy, effectively reduce cracks, enhance the continuity of dielectric materials, and reduce local stress concentration caused by shock waves being blocked, thus greatly improving the impact resistance of foamed cement boards.

The beneficial effect of the present invention is that: the present invention is a foamed cement board using leftovers of the foamed cement board as recycled aggregates, which has high strength, good thermal insulation performance, convenient construction, and is convenient for improving production and construction efficiency. The product of the invention adopts a large number of industrial wastes as raw materials, has low material cost, and has remarkable economic and environmental benefits. The foamed cement board prepared by the invention has high strength and good thermal insulation performance, and can be used for external thermal insulation of exterior walls of building construction.

Detailed ways

The present invention is further illustrated below by way of examples.

Example 1, a foamed cement board produced with foamed cement board scraps as aggregate, 100 grades of ordinary Portland cement, 5 fly ash, 20 recycled aggregates, 4 hydrogen peroxide, zinc stearate 1. Bentonite 1, sulfate early-strength agent 0.5, water reducer 0.5, polypropylene fiber 1, water-cement ratio 0.64, stir evenly according to the determined mixing process, and the desired product can be obtained. The performance test results are shown in Table 1.

Example 2, a foamed cement board using the leftovers of the foamed cement board as recycled aggregates, according to 52.5 grade ordinary Portland cement 100, fly ash 30, recycled aggregate 50, hydrogen peroxide 6, zinc stearate 6. Bentonite 5, metaaluminate early-strength agent 1, water reducer 2, polypropylene fiber 4, water-cement ratio is 0.64, stir evenly according to the determined stirring process, and the desired product is obtained. The performance test results are shown in Table 1.

Example 3, a foamed cement board using the leftovers of the foamed cement board as recycled aggregates, according to 52.5 grade ordinary Portland cement 100, fly ash 20, recycled aggregate 35, hydrogen peroxide 7, zinc stearate 4. Bentonite 7, sulfate early-strength agent 3, water reducer 3, polypropylene fiber 2, water-cement ratio is 0.64, stir evenly according to the determined stirring process, and the desired product is obtained. The performance test results are shown in Table 1.

Example 4, a foamed cement board using the leftovers of the foamed cement board as recycled aggregates, according to 42.5 grade ordinary Portland cement 100, fly ash 30, recycled aggregate 50, hydrogen peroxide 10, zinc stearate 10. Bentonite 15, metaaluminate early-strength agent 4, water reducer 5, polypropylene fiber 10, water-cement ratio is 0.64, stir evenly according to the determined stirring process, and the desired product is obtained. The performance test results are shown in Table 1.

Table 1 embodiment performance test result

Claims (8)

1. take the foam cement plate that foam cement plate tankage are regenerated aggregate for one kind, it is characterized in that this foam cement plate is comprised of ordinary Portland cement, flyash, regenerated aggregate, hydrogen peroxide, Zinic stearas, wilkinite, hardening accelerator, water reducer and polypropylene fibre, the weight ratio of each component is:

Ordinary Portland cement 100

Flyash 5-30

Regenerated aggregate 20-50

Hydrogen peroxide 4-10

Zinic stearas 1-10

Wilkinite 1-15

Hardening accelerator 0.5-4

Water reducer 0.5-5

Polypropylene fibre 1-10;

Wherein: described regenerated aggregate is that foam cement plate tankage form through crushing and screening, and maximum particle diameter is 2.5mm, and tap density is (300-800) kg/m ³, voidage is 13%-25%; The shared weight percent of each particle size range wherein: 1.25 mm-2.5mm diameter is 9.5%; 0.16 mm-1.25mm diameter is 65.4%; Being less than 0.16mm diameter is 25.1%; Described wilkinite is sodium bentonite, and described hardening accelerator is a kind of in vitriol or meta-aluminate, and described water reducer is sulfamate based water reducer;

Described foam cement plate obtains by following preparation method, and concrete steps are as follows:

(1) foam cement plate tankage are broken, pass through successively 2.5mm, 1.25mm, the screen cloth of 0.16mm, obtains particle size range and is respectively 1.25 mm-2.5mm, and 0.16-1.25mm is less than three kinds of regenerated aggregates of 0.16mm;

(2) by the shared weight percent preparation of each particle size range regenerated aggregate: 1.25mm-2.5mm, be 9.5%; 0.16 mm-1.25mm is 65.4%; Being less than 0.16mm is 25.1%;

(3) take by weight proportion step (2) gained regenerated aggregate, ordinary Portland cement, flyash, Zinic stearas, wilkinite, hardening accelerator, water reducer and the polypropylene fibre having prepared, adding water stirs, mix again hydrogen peroxide and stir 20s, pour die for molding into, the demoulding after 1d, and cut according to required specification, obtain desired product.

2. according to claim 1ly take the foam cement plate that foam cement plate tankage are regenerated aggregate, it is characterized in that the weight ratio of each component is:

Ordinary Portland cement 100

Flyash 10-20

Regenerated aggregate 25-45

Hydrogen peroxide 5-8

Zinic stearas 2-6

Wilkinite 3-10

Hardening accelerator 1-3

Water reducer 1-3

Polypropylene fibre 2-5.

3. according to claim 1ly take the foam cement plate that foam cement plate tankage are regenerated aggregate, it is characterized in that described ordinary Portland cement is a kind of in 42.5 grades or 52.5 grades of ordinary Portland cements.

4. according to claim 1ly take the foam cement plate that foam cement plate tankage are regenerated aggregate, it is characterized in that described flyash is I level high-calcium fly ass, its free calcium oxide content≤3.0%, loss on ignition≤5.0%.

5. according to claim 1ly take the foam cement plate that foam cement plate tankage are regenerated aggregate, the mass concentration that it is characterized in that described hydrogen peroxide is 30%.

6. according to claim 1ly take the foam cement plate that foam cement plate tankage are regenerated aggregate, it is characterized in that described Zinic stearas is white powder, chemical pure, zinc oxide content 13.5%-15.5%.

7. according to claim 1ly take the foam cement plate that foam cement plate tankage are regenerated aggregate, it is characterized in that described polypropylene fibre is that length is the polypropylene fibre of 3mm-9mm.

8. a preparation method of take the foam cement plate that foam cement plate tankage are regenerated aggregate as claimed in claim 1, is characterized in that concrete steps are as follows:

(1) foam cement plate tankage are broken, pass through successively 2.5mm, 1.25mm, the screen cloth of 0.16mm, obtains particle size range and is respectively 1.25 mm-2.5mm, and 0.16-1.25mm is less than three kinds of regenerated aggregates of 0.16mm;

(2) by the shared weight percent preparation of each particle size range regenerated aggregate: 1.25mm-2.5mm, be 9.5%; 0.16 mm-1.25mm is 65.4%; Being less than 0.16mm is 25.1%;

(3) take by weight proportion step (2) gained regenerated aggregate, ordinary Portland cement, flyash, Zinic stearas, wilkinite, hardening accelerator, water reducer and the polypropylene fibre having prepared, adding water stirs, mix again hydrogen peroxide and stir 20s, pour die for molding into, the demoulding after 1d, and cut according to required specification, obtain desired product.