CN111574130A - Long-flocculation-time as-cast finish concrete and preparation method thereof - Google Patents

Abstract

The invention discloses a long-flocculation-time fair-faced concrete and a preparation method thereof, and relates to the field of coatings. The fair-faced concrete with long-acting open time and air purification can solve the problems that the cement inorganic material has short setting time and is inconvenient for long-time construction, greatly simplifies the construction process and procedure of the fair-faced concrete veneer, and prevents the problems of cracking, color difference and the like of the cement surface; the added molecular sieve and mixed crystal titanium dioxide in the product can adsorb and decompose toxic and harmful gases such as formaldehyde, benzene and the like in indoor air under natural light, and the product has high purification efficiency and lasting purification effect.

Description

Long-flocculation-time as-cast finish concrete and preparation method thereof

Technical Field

The invention relates to the technical field of decorative materials, in particular to a long-flocculation-time fair-faced concrete and a preparation method thereof.

Background

The fair-faced concrete is an expression technique of modern building, after concrete pouring, materials such as coating, tile pasting, stone pasting and the like do not exist any more, and the method is a plain technique for expressing the concrete, and is also called as decorative concrete due to the extremely good decorative effect. The traditional cast concrete adopts a special template and specially prepared concrete for one-time casting molding. The cement has short opening time, so the requirements on materials and a forming process are high, color blocks are required to be printed for color adjustment before all cement is poured, and indoor doors, walls, holes and members are required to be accurately designed and installed; and in the curing process and the curing process after cement pouring, phenomena such as cracks, alkali return, rusty spots and the like are easy to occur, so that the popularization and the application of the process are influenced.

As a novel building decoration material, the as-cast finish concrete coating is more and more widely applied to building engineering, can achieve the ideal decorative effect of as-cast finish concrete as long as the construction is legal, strictly controlled and finely designed, and realizes the cost saving and the construction efficiency while pursuing the appreciation taste. The prior art of the clear water imitation concrete coating mainly comprises two types, one is dry powder mortar, and the other is water-based thick mortar, compared with the dry powder mortar, the dry powder mortar has more vivid effect, but because inorganic cementing materials such as cement are added into the dry powder mortar, the initial setting time of the cement is generally 1-3 hours, and the final setting time is 4-6 hours, the material has shorter opening time and higher construction pressure; the aqueous thick paste also needs color mixing treatment, the process is complicated and a higher color mixing technology is needed; in addition, as indoor decoration materials, the two materials do not have the purification effect on formaldehyde, benzene and the like, and with the increasing diversification of the indoor decoration materials, a large amount of synthetic materials such as glue, plates and the like are used, so that after finishing decoration, the content of indoor formaldehyde seriously exceeds the standard, and after the decoration is exposed in the environment for a long time, the formaldehyde can cause harm to the health of human bodies, and with the development of social science, the environmental awareness of people is continuously improved, and the environment-friendly indoor decoration materials are more popular.

Therefore, the problem to be solved by those skilled in the art is how to provide a clear water concrete and a preparation method thereof, wherein the clear water concrete can prolong the material opening time, does not need to be toned, and has an indoor air purification function.

Disclosure of Invention

In view of the above, the invention provides the imitated clear water concrete which is environment-friendly and pollution-free, has no toxic or harmful effect on human bodies, can prolong the opening time of the material and can firmly and effectively absorb a large amount of toxic and harmful substances in purified air and the preparation process thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

the clear water-imitated concrete with long flocculation time comprises the following components in parts by weight: 15-40 parts of cement, 30-40 parts of quartz sand, 0.2-0.4 part of starch ether, 3.15-7.3 parts of water reducing material, 0.3-0.4 part of cellulose ether, 3-8 parts of rubber powder, 0.5-1 part of wood fiber, 12-20 parts of double flying powder, 10-15 parts of ash calcium and 0.2-0.5 part of mixed crystal titanium dioxide.

Preferably, the composition comprises the following components in parts by weight: 26 parts of cement, 36 parts of quartz sand, 0.3 part of starch ether, 5.25 parts of a water reducing material, 0.35 part of cellulose ether, 7 parts of rubber powder, 0.8 part of wood fiber, 13 parts of double flying powder, 11 parts of ash calcium and 0.3 part of mixed crystal titanium dioxide.

Preferably, the cement is one or a combination of two of white portland cement, black portland cement, sulphoaluminate cement or ferro-aluminate cement, and the strength grade is 32.5.

Preferably, the quartz sand is one of white quartz sand of 80-120 meshes and white quartz sand of 60-80 meshes, and the talcum powder is 800 meshes.

Preferably, the starch ether is modified starch ether for building mortar, the cellulose ether is one or two of hydroxyethyl cellulose ether, hydroxypropyl methyl cellulose ether and methyl cellulose ether, and the rubber powder is one or two of yilaitai FX2350, 60W and 80W.

Preferably, the water-reducing material is a polyol and derivatives thereof and a molecular sieve in a weight ratio of 0.25: 5 or 0.15: 5 proportion of the mixture after high-speed shearing and dispersion, the particle size is 270-340 meshes.

Preferably, the molecular sieve is one or more of 3A, 4A, 5A, 10X and 15X silicon-based porous materials.

The beneficial effects of the preferred technical scheme are as follows: a molecular sieve is an artificially synthesized aluminosilicate having a microporous cubic lattice, which adsorbs or repels molecules of various substances depending on the size of pores inside its crystal, and is thus called a "molecular sieve". Substances with a molecular diameter smaller than the pore diameter of the molecular sieve crystals can enter the molecular sieve crystals and thus be adsorbed, otherwise, be rejected. The specific surface area of the molecular sieve is generally 300-1000 m²The pore diameter is about 0.5 nm. The material molecular sieve, the polyol and the derivatives thereof are mixed and compounded through high-speed shearing, so that the polyol and the derivatives thereof are more dispersed in the molecular sieve pore channels, after the material molecular sieve, the polyol and the derivatives thereof are mixed and dispersed with cement, the water reducing material is adsorbed on the surface of cement particles, a compact adsorption film layer is formed in the using process, the double electric layer structure on the surface of the cement particles is changed, water is difficult to contact with the cement, and the process of water adsorption of the cement particles and hydration reaction are inhibited; in addition, because the polyhydric alcohol and the derivatives thereof in the pore channels are slowly released, the forming time of the permeable membrane is longer, and the molecular sieve is attached to the surface of the cement particles, so that the contact area of the cement particles and water is reduced, and the effect of delaying the hydration reaction of the cement is also achieved. In addition, the molecular diameter of formaldehyde is 0.45nm, the molecular diameter of benzene is 0.58nm, and after the material is dried on the wall, toxic and harmful gases such as formaldehyde, benzene and the like can enter the molecular sieve pore channels along with the air flow, so that the toxic and harmful gases are adsorbed by the molecular sieve.

Preferably, the preparation method of the mixed crystal titanium dioxide comprises the following steps:

stirring one of titanium salt and anhydrous ethanol in an acetylacetone or glacial acetic acid solvent for 2-10 h, wherein the weight ratio of the titanium salt to the anhydrous ethanol to the acetylacetone or glacial acetic acid solvent is 1 (1.5-4) to 0.1-0.3, fully stirring uniformly, adding an ethanol solution with the volume concentration of 20%, wherein the weight ratio of the titanium salt to the 20% ethanol solution is 1 (0.5-1.2), standing for 5-24 h to form nano mixed crystal TiO₂Putting the sol into a drying oven, drying at 100-150 ℃, then putting into a muffle furnace, and drying at 500-550 DEG CRoasting for 30-60 min, naturally cooling, taking out, and grinding to obtain the mixed crystal titanium dioxide.

Preferably, the particle size of the mixed crystal titanium dioxide is more than or equal to 200 meshes.

The beneficial effects of the preferred technical scheme are as follows: the mixed crystal titanium dioxide is a photocatalyst, and when the photon energy reaches or exceeds the nano TiO₂When the band gap energy is available, electrons are excited from a valence band to a conduction band to become photogenerated electrons, and corresponding holes are generated on the valence band; the valence band hole is a good oxidant and the photogenerated electron is a good reductant. The photo-generated electrons generally react with surface-adsorbed oxygen molecules, and the holes react with surface-adsorbed water and OH^-The ion reaction forms hydroxyl with strong oxidability; the strong oxidizing property of the hydroxyl can oxidize organic matters into simple inorganic matters such as carbon dioxide, water and the like, and finally the purpose of degrading harmful organic matters such as formaldehyde and the like is achieved.

The invention also provides a preparation method of the imitation fair-faced concrete with long flocculation time, which comprises the following steps:

(1) screening raw material cement through a vibrating screen with a screen mesh of 40 meshes, and weighing the screened cement and raw materials thereof according to parts by weight for later use;

(2) weighing water reducing material, cement, starch ether, cellulose ether, wood fiber and mixed crystal titanium dioxide according to a weight ratio, adding into a closed high-speed dispersion machine, and stirring at a rotating speed of 800r/min for 8min to obtain a mixed material;

(3) adding the mixed material, quartz sand, rubber powder, calcium carbonate and double-flying powder into a dry powder mixer, stirring for 30min, and sieving with a 30-mesh vibrating screen to obtain the finished product.

Through the technical scheme, compared with the prior art, the invention provides the fair-faced concrete with long flocculation time and the preparation method thereof. In addition, because the polyhydric alcohol and the derivatives thereof in the pore channels are slowly released, the forming time of the permeable membrane is longer, and the molecular sieve is attached to the surface of the cement particles, so that the contact area of the cement particles and water is reduced, and the effect of delaying the hydration reaction of the cement is also achieved. The open time of the stirred material can be effectively prolonged, and the construction time is long enough for a constructor to use;

the clear water-imitating concrete coating is simple and convenient to construct, environment-friendly, pollution-free and harmless to human bodies, and the molecular sieve and the mixed crystal titanium dioxide are used as materials for adsorbing/decomposing toxic and harmful substances, so that toxic and harmful gases such as formaldehyde, benzene and the like in indoor air can be efficiently adsorbed/decomposed by a proper pore passage and a high specific surface area, the purification efficiency is high, and the purification effect is lasting. Through detection, the clean water imitation concrete coating has the purification performance of 91.5 percent on formaldehyde in indoor air within 48 hours, the purification effect durability of 88.5 percent, the purification performance of 84.8 percent on benzene and the purification effect durability of 78.4 percent, and has higher popularization and application values.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Preparing mixed crystal titanium dioxide:

stirring one of titanium salt and anhydrous ethanol in an acetylacetone or glacial acetic acid solvent for 2-10 h, wherein the weight ratio of the titanium salt to the anhydrous ethanol to the acetylacetone (or glacial acetic acid) solvent is 1 (1.5-4) to (0.1-0.3), fully stirring uniformly, adding an ethanol solution with the volume concentration of 20%, wherein the weight ratio of the titanium salt to the 20% ethanol solution is 1 (0.5-1.2), standing for 5-24 h to form a nano mixed crystal TiO2 sol, then putting the sol into a drying oven, drying at 100-150 ℃, then putting into a muffle furnace, roasting at 500-550 ℃ for 30-60 min, naturally cooling, taking out, and grinding to obtain the mixed crystal titanium dioxide.

Preparing a water reducing agent:

polyol and its derivatives and molecular sieve in a ratio of 0.25: 5 or 0.15: 5, taking the mixture subjected to high-speed shearing dispersion as a water reducing material for later use;

wherein the molecular sieve is one or more of 3A, 4A, 5A, 10X and 15X silicon-based porous materials.

The preparation process comprises the following steps:

(1) screening raw material cement through a vibrating screen with a screen mesh of 40 meshes, and weighing the screened cement and raw materials thereof according to parts by weight for later use;

(2) weighing water reducing material, cement, starch ether, cellulose ether, wood fiber and mixed crystal titanium dioxide according to a weight ratio, adding into a closed high-speed dispersion machine, and stirring at a rotating speed of 800r/min for 8min to obtain a mixed material;

(3) adding the mixed material, quartz sand, rubber powder, calcium carbonate and double-flying powder into a dry powder mixer, stirring for 30min, and sieving with a 30-mesh vibrating screen to obtain the finished product.

The following examples will illustrate specific raw material ratios.

Raw materials	Example 1	Example 2	Example 3	Example 4	Example 5
						Cement	20	30	26	15	40
Quartz sand	35	30	36	40	30
						Starch ethers	0.3	0.3	0.3	0.4	0.2
Water reducing material	7.2	3.2	5.25	5.2	3.8
						Cellulose ethers	0.3	0.3	0.35	0.4	0.3
Rubber powder	6	7	7	3	3
						Wood fiber	1	1	0.8	0.5	0.5
Double-flying powder	17	17	13	20	12
						Lime calcium	13	11	11	15	10
Mixed crystal titanium dioxide	0.2	0.2	0.3	0.5	0.2
						Total up to	100	100	100	100	100

Test examples

1) And (3) measuring the open time of the material by a finger pressure method:

all the similar containers are taken, and the same amount of the imitation fair-faced concrete is mixed according to the powder-water ratio of 1: 0.42 initial time after stirring and end time when the mixture was left until the finger lightly pressed to the surface did not stick to the material. The detection result of the embodiment 1 is 25h30min, the detection result of the embodiment 2 is 22h, the detection result of the embodiment 3 is 24h30min, the detection result of the embodiment 4 is 27h, the detection result of the embodiment 3 is 20h20min, and compared with the bare concrete material, the open time of the bare concrete material after being placed is 6h-10h, the construction pressure can be effectively relieved, and after the constructor stirs the material on the same day, the constructor can also use the material after being constructed the next day.

2) According to the standard requirements of indoor air purification function coating material purification performance, indoor air purification performance detection is respectively carried out on the clear water-imitating concrete prepared in the embodiments 1 to 5. The test results are shown in the following table:

the test results show that compared with the blank comparison cabin, the concentrations of formaldehyde and benzene in the cabin after 48 hours of the examples 1 to 5 are obviously lower than the corresponding concentrations in the blank cabin; the purification rates of 90.5% and 81.4% for formaldehyde and benzene in 48 hours of example 1, 89.7% and 80.2% for formaldehyde and benzene in 48 hours of example 2, 91.5% and 84.8% for formaldehyde and benzene in 48 hours of example 3, 91.3% and 84.3% for formaldehyde and benzene in 48 hours of example 4, and 87.5% and 78.4% for formaldehyde and benzene in 48 hours of example 5, respectively, show that the fair-faced concrete of the present invention has a good purification effect on formaldehyde, benzene, and the like.

3) According to the standard requirements of 'limit of harmful substances in interior wall coating of interior decoration and finishing materials', the limit of harmful substances in the simulated clear water concrete prepared in the embodiments 1 to 5 is respectively detected. The test results are shown in the following table:

the embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. The clear water-imitated concrete with long flocculation time is characterized by comprising the following components in parts by weight: 15-40 parts of cement, 30-40 parts of quartz sand, 0.2-0.4 part of starch ether, 3.15-7.3 parts of water reducing material, 0.3-0.4 part of cellulose ether, 3-8 parts of rubber powder, 0.5-1 part of wood fiber, 12-20 parts of double flying powder, 10-15 parts of ash calcium and 0.2-0.5 part of mixed crystal titanium dioxide.

2. The clear water concrete with long flocculation time as claimed in claim 1, which is characterized by comprising the following components in parts by weight: 26 parts of cement, 36 parts of quartz sand, 0.3 part of starch ether, 5.25 parts of a water reducing material, 0.35 part of cellulose ether, 7 parts of rubber powder, 0.8 part of wood fiber, 13 parts of double flying powder, 11 parts of ash calcium and 0.3 part of mixed crystal titanium dioxide.

3. The clear water concrete of claim 1 or 2, wherein the cement is one or a combination of white portland cement, black portland cement, sulphoaluminate cement or ferro-aluminate cement, and has a strength grade of 32.5.

4. The clear water concrete with long flocculation time as claimed in claim 1 or 2, wherein the silica sand is one of white 80-120 mesh silica sand and white 60-80 mesh silica sand, and the talc powder is 800 mesh.

5. The long-flocculation-time artificial clear water concrete according to claim 1 or 2, wherein the starch ether is modified starch ether for building mortar, the cellulose ether is one or two of hydroxyethyl cellulose ether, hydroxypropyl methyl cellulose ether and methyl cellulose ether, and the rubber powder is one or two of yilaitai FX2350, 60W and 80W.

6. The long flocculation time simulated clear water concrete as claimed in claim 1 or 2, wherein the water reducing material is a polyol and its derivatives and molecular sieve in a ratio of 0.25: 5 or 0.15: 5, mixing the mixture after high-speed shearing and dispersing.

7. The long flocculation time simulated clear water concrete of claim 6, wherein the molecular sieve is one or more of 3A, 4A, 5A, 10X and 15X silicon-based porous materials.

8. The clear water concrete imitation with long flocculation time according to claim 1 or 2, wherein the preparation method of the mixed crystal titanium dioxide comprises the following steps:

stirring one of titanium salt and anhydrous ethanol in an acetylacetone or glacial acetic acid solvent for 2-10 h, wherein the weight ratio of the titanium salt to the anhydrous ethanol to the acetylacetone or glacial acetic acid solvent is 1 (1.5-4) to 0.1-0.3, fully stirring uniformly, adding an ethanol solution with the volume concentration of 20%, wherein the weight ratio of the titanium salt to the 20% ethanol solution is 1 (0.5-1.2), standing for 5-24 h to formNano mixed crystal TiO₂And (3) sol, putting the sol into a drying oven, drying at 100-150 ℃, then putting into a muffle furnace, roasting at 500-550 ℃ for 30-60 min, naturally cooling, taking out, and grinding to obtain the mixed crystal titanium dioxide.

9. The clear water concrete imitation with long flocculation time of claim 8, wherein the particle size of the mixed crystal titanium dioxide is not less than 200 meshes.

10. A method for preparing a long flocculation time imitation fair-faced concrete according to any one of claims 1 to 9, comprising the following steps:

(1) screening raw material cement through a vibrating screen with a screen mesh of 40 meshes, and weighing the screened cement and raw materials thereof according to parts by weight for later use;

(2) weighing water reducing material, cement, starch ether, cellulose ether, wood fiber and mixed crystal titanium dioxide according to a weight ratio, adding into a closed high-speed dispersion machine, and stirring at a rotating speed of 800r/min for 8min to obtain a mixed material;

(3) adding the mixed material, quartz sand, rubber powder, calcium carbonate and double-flying powder into a dry powder mixer, stirring for 30min, and sieving with a 30-mesh vibrating screen to obtain the finished product.