CN114804739A - High-strength foam concrete with double-doped fly ash and preparation method thereof - Google Patents

Abstract

The invention discloses a high-strength foam concrete with double-doped fly ash, which comprises the following components: 50-100 parts of cement, 50-100 parts of ultrafine powder, fly ash, water, a composite polymer foaming agent solution, an additive and anti-crack fibers; a preparation method of high-strength foam concrete with double-doped fly ash comprises the following steps: s1, calculating the material quantity required by each cubic meter; s2, weighing the use amount of the materials; s3, mixing the materials together by using a stirrer; s4, sequentially adding the admixture, mixing water and polypropylene fibers into a stirrer to prepare a gelled slurry; s5, diluting water and a foaming agent into a foaming agent solution, and preparing foam through a foaming machine; and S6, stirring the gelled slurry and the foam by using a stirrer to prepare the foam concrete. And S7, pouring the mixture into a mould to manufacture the foam concrete light member. The invention has the advantages that: the cracking of the foam concrete is prevented, the time for setting and hardening of the foam concrete is shortened, and the physical and mechanical properties of the foam concrete are improved.

Description

High-strength foam concrete with double-doped fly ash and preparation method thereof

Technical Field

The invention relates to the technical field of foam concrete walls, in particular to high-strength foam concrete with double-doped fly ash and a preparation method thereof.

Background

The foam concrete is porous novel light heat-insulating concrete, and can be formed by mixing foam and cement paste in a mechanical foaming mode and naturally curing. The foam concrete has the following advantages: the heat preservation performance is good; the fire resistance and heat resistance are good; sound insulation and absorption; and (3) light weight. However, in the preparation process of the foam concrete, the foam concrete is easily influenced by the foam quality to generate a defoaming phenomenon, so that the problem of shrinkage cracking is caused, and the strength of the foam concrete is greatly influenced. Meanwhile, the physical and mechanical properties of the foam concrete are greatly restricted due to the defects of longer coagulation and hardening time of the foam concrete, high requirement on maintenance conditions and the like.

The advantages of the foam concrete determine that the foam concrete has good use function and mechanical property, and can be widely applied to house and roof heat insulation construction, wall heat insulation material cast-in-place, light wallboard products and the like. Under the large background of national development of green buildings, the foam concrete plays an important role in the field of building energy conservation in the future. At present, the preparation method of the ultra-light foam concrete with large fly ash content in the market is provided, the fly ash accounting for 25-47% of the total weight of the raw materials is introduced to reduce the consumption of the cement of the foam concrete product, and the density and the heat conductivity coefficient of the fly ash foam concrete are reduced by combining the physical foaming method and the chemical foaming method.

The existing preparation method contains a large amount of fly ash, the fly ash is essentially an industrial waste material with poor uniformity and unicity, the fly ash is not a structural reinforcing material, the strength of the foam concrete can be seriously reduced by introducing a large amount of fly ash, and meanwhile, the foam concrete has the problems of shrinkage and cracking easily caused by more cementing materials and large water-cement ratio in raw materials.

Disclosure of Invention

The invention aims to solve the technical problems and provides the fly ash double-doped high-strength foam concrete and the preparation method thereof, wherein the fly ash double-doped high-strength foam concrete is used for preventing the foam concrete from cracking, reducing the setting and hardening time of the foam concrete and improving the physical and mechanical properties of the foam concrete.

In order to solve the technical problems, the technical scheme provided by the invention is as follows: the high-strength foam concrete with double-doped fly ash comprises the following components in parts by weight: 450 parts of cement 380-.

As an improvement, the admixture comprises an early strength agent, a water reducing agent, a foam stabilizer and cellulose ether, wherein the ratio of the early strength agent to the water reducing agent to the foam stabilizer to the cellulose ether is 10: 1: 1: 1.

as an improvement, the anti-crack fibers are polypropylene fibers.

A preparation method of high-strength foam concrete with double-doped fly ash comprises the following steps:

s1, respectively calculating the mass m1 of cement, the mass m2 of dried ultrafine powder, the mass m3 of dried fly ash, the mass m4 of a composite high-molecular foaming agent, the mass m5 of mixing water and the mixing amount of anti-crack fibers and an additive required by each cubic meter according to a mixing ratio design method;

s2, weighing the materials according to the volume of the foam concrete required in the actual engineering, wherein the weighing precision is 0.5%;

s3, sequentially adding weighed materials such as cement, ultrafine powder and fly ash into a stirrer, and stirring for 60S to uniformly mix the materials together;

s4, sequentially adding the admixture, mixing water and polypropylene fibers into a stirrer, and stirring for about 3 minutes to prepare a gelling slurry;

s5, mixing water and foaming agent according to the ratio of 1: 30 into foaming agent solution, and physically foaming by a foaming machine to obtain foam required by foam concrete preparation;

and S6, pouring the foam obtained in the step into a stirrer for preparing the gelled slurry, uniformly stirring the gelled slurry and the foam for about 5 minutes, and finally preparing the foam concrete.

And S7, pouring the stirred foam concrete into a mould to manufacture various foam concrete light members, and performing standard maintenance.

Compared with the prior art, the invention has the advantages that:

the superfine powder is used to replace cement and fly ash, and the mixing amount of the superfine fly ash accounts for about 20% of the cement consumption. From the production process, the ultrafine fly ash fills gaps of cement particles and is fully mixed with cement when dry materials are stirred, so that the material proportion of the foam concrete is improved to a great extent; when the materials are stirred by adding water, the materials are quickly subjected to hydration reaction with cement to generate high-density gelled slurry, so that the compressive strength of the foam concrete is effectively increased; and (3) filling partial holes and pores of the foam concrete when the gelled slurry is added with foaming agent and stirred, replacing free water in the pores of the cement, and compacting the foam concrete.

By changing the types and the mixing amounts of the additives, the proportion relationship of the additives is as follows: early strength agent: water reducing agent: foam stabilizer: cellulose ether 10: 1: 1: 1, the proportion relation is adapted to the matching ratio of the high-strength foam concrete with double-doped fly ash, the strength and the setting and hardening speed of the foam concrete can be greatly improved, and the physical and mechanical properties of the foam concrete are improved in an all-round way.

Drawings

FIG. 1 is a flow chart of a preparation method of high-strength foam concrete with double-doped fly ash.

FIG. 2 is a system diagram of the additive synergy of a double-doped fly ash high-strength foam concrete of the present invention.

Detailed Description

Examples

The high-strength foam concrete with double-doped fly ash comprises the following components in parts by weight: 380 portions of cement, 50 to 100 portions of ultrafine powder, 130 portions of fly ash, 140 portions of water, 250 portions of water, 130 portions of composite polymer foaming agent solution, 26 portions of admixture and 1.5kg/m3 of anti-cracking fiber.

Wherein the admixture comprises an early strength agent, a water reducing agent, a foam stabilizer and cellulose ether, and the ratio of the early strength agent to the water reducing agent to the foam stabilizer to the cellulose ether is 10: 1: 1: 1, adopting polypropylene fiber as the anti-crack fiber.

A preparation method of high-strength foam concrete with double-doped fly ash comprises the following steps:

s1, respectively calculating the mass m1 of cement, the mass m2 of dried ultrafine powder, the mass m3 of dried fly ash, the mass m4 of a composite high-molecular foaming agent, the mass m5 of mixing water and the mixing amount of anti-crack fibers and an additive required by each cubic meter according to a mixing ratio design method;

s2, weighing the materials according to the volume of the foam concrete required in the actual engineering, wherein the weighing precision is 0.5%;

s3, sequentially adding weighed materials such as cement, ultrafine powder and fly ash into a stirrer, and stirring for 60S to uniformly mix the materials together;

s4, sequentially adding the admixture, mixing water and polypropylene fibers into a stirrer, and stirring for about 3 minutes to prepare a gelling slurry;

s5, mixing water and foaming agent according to the ratio of 1: 30 into foaming agent solution, and physically foaming by a foaming machine to obtain foam required by foam concrete preparation;

and S6, pouring the foam obtained in the step into a stirrer for preparing the gelled slurry, uniformly stirring the gelled slurry and the foam for about 5 minutes, and finally preparing the foam concrete.

And S7, pouring the stirred foam concrete into a mould to manufacture various foam concrete light members, and performing standard maintenance.

The ultrafine powder is adopted to further replace fly ash and cement, because the ultrafine fly ash has high hydration activity and the average grain diameter is only 46 percent of that of common fly ash, the mixing amount of the fly ash is greatly increased when cement or plastic concrete with the same strength grade is prepared. In the process of stirring the dry materials, the ultrafine fly ash is mixed into the cement, and because the shape of the ultrafine fly ash is a spherical glass body with different sizes and smooth and compact surfaces and the particle size is far smaller than that of the cement, the amount of the ultrafine fly ash mixed into the cement is increased, so that the quantity of dry material particles is increased, the structure is more and more compact, gaps among cement particles are filled, and the amount of the ultrafine fly ash substituted for the cement at the same level is far larger than that of other admixtures such as fly ash and silica fume; in the process of adding water and stirring, the superfine powder has small particle size and more particles, and the total surface area is larger than that of normal fly ash. After being stirred with water, active Al2O3 and SiO2 in the ultrafine powder can quickly generate hydration reaction with Ca (OH)2 in the gelled material to generate high-density slurry; in the process of adding the foaming agent and stirring the foam, the cementing material slurry and the foaming agent foam are fused to generate the foam concrete, a large number of holes and gaps are generated in the concrete, and the ultrafine fly ash micro-particles fill partial hole structures and gaps in the foam concrete in the process, so that the strength of the foam concrete is increased to a great extent, and free water in the gaps of the cement particles is replaced, so that the content of the free water in the mixture is increased, and the excellent water reducing performance of the ultrafine powder in the process of stirring the foam concrete is reflected.

When the mold is poured, the contact surface of the foam concrete and the surface of the mold cannot be guaranteed to be smooth, small holes can be formed, the surface of a poured test piece is not smooth, and a plurality of small holes are distributed on the surface of the test piece. Therefore, a small amount of ultrafine fly ash is selected and diluted by adding water to form ultrafine fly ash slurry, and a layer of ultrafine fly ash slurry is coated on a mould in advance before foam concrete is poured. In order to prevent the slurry from sliding down along the surface of the mold, the water adding amount is strictly controlled, and the foam concrete is poured after the surface of the slurry is slightly solidified, so that the superfine fly ash slurry is firstly contacted with the foam concrete, and the pores on the surface of the foam concrete can be effectively filled due to the small particle size and the smooth and compact surface of the superfine powder, so that the surface of a foam concrete test piece is smooth. Meanwhile, free water in holes on the surface of the test piece can be replaced by particles in the ultrafine powder slurry, excessive water evaporation on the surface of the foam concrete test piece is avoided, the surface workability of the foam concrete test piece is improved, the viscosity is reduced, the foam concrete can flow on the surface of the mold when the foam concrete test piece is contacted with the mold, the foam concrete is prevented from being attached to the mold when the viscosity is low, and the foam concrete is prevented from being detached together with the mold when the mold is demolded. The surface of the foam concrete test piece doped with the ultrafine powder can be smoother without holes by integrating the efficacy of the ultrafine powder, so that the test piece can achieve the effect of plastering-free on the surface of the test piece when being applied in the actual construction process, and the construction procedures and the construction time are greatly reduced.

Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.

Claims (4)

1. The high-strength foam concrete with double-doped fly ash is characterized by comprising the following components in parts by weight: 450 parts of cement 380-.

2. The high-strength foamed concrete with double-doped fly ash as claimed in claim 1, wherein: the admixture comprises an early strength agent, a water reducing agent, a foam stabilizer and cellulose ether, wherein the ratio of the early strength agent to the water reducing agent to the foam stabilizer to the cellulose ether is 10: 1: 1: 1.

3. the high-strength foamed concrete with double-doped fly ash as claimed in claim 1, wherein: the anti-crack fibers are polypropylene fibers.

4. The preparation method of the high-strength foam concrete with double-doped fly ash is characterized by comprising the following steps:

s1, respectively calculating the mass m1 of cement, the mass m2 of dried ultrafine powder, the mass m3 of dried fly ash, the mass m4 of a composite high-molecular foaming agent, the mass m5 of mixing water and the mixing amount of anti-crack fibers and an additive required by each cubic meter according to a mixing ratio design method;

s2, weighing the materials according to the volume of the foam concrete required in the actual engineering, wherein the weighing precision is 0.5%;

s3, sequentially adding weighed materials such as cement, ultrafine powder and fly ash into a stirrer, and stirring for 60S to uniformly mix the materials together;

s4, sequentially adding the admixture, mixing water and polypropylene fibers into a stirrer, and stirring for about 3 minutes to prepare a gelling slurry;

s5, mixing water and foaming agent according to the ratio of 1: 30 into foaming agent solution, and physically foaming by a foaming machine to obtain foam required by foam concrete preparation;

and S6, pouring the foam obtained in the step into a stirrer for preparing the gelled slurry, uniformly stirring the gelled slurry and the foam for about 5 minutes, and finally preparing the foam concrete.

And S7, pouring the stirred foam concrete into a mould to manufacture various foam concrete light members, and performing standard maintenance.

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