CN114315271A - White clear water finish concrete for assembly type component and preparation method - Google Patents

Abstract

The invention discloses white clear water finish concrete for an assembled component and a preparation method thereof. Each cubic concrete comprises the following components in parts by weight: 300-370 kg of cement, 50-130 kg of admixture, 820-950 kg of coarse aggregate, 730-980 kg of fine aggregate, 0.057-15 kg of homogeneity regulator, 5-13 kg of water reducer, 150-170 kg of water and 0-32 kg of titanium dioxide. The invention can obtain white fair-faced concrete with the requirements of light white of C35-C50 grade and high whiteness above beige, meets the requirements of high early strength and quick demoulding of members, is green and environment-friendly, has lower cost, flexible and adjustable fluidity, smooth and fine concrete surface, uniform color and luster, basically consistent color, no need of secondary decoration, no need of modification or addition of production equipment, and has practical production operability and popularization value.

Description

White clear water finish concrete for assembly type component and preparation method

Technical Field

The invention relates to the field of building materials, in particular to white clear water finish concrete for an assembled member and a preparation method thereof.

Background

The clear concrete belongs to the category of decorative concrete, and due to the unique preparation technology and construction process, after one-step pouring forming, the natural surface effect of the concrete, which is uniform in color, flat and smooth and has clear edges and corners, is used as a decorative surface, and no external decoration is performed, so that the clear concrete is very solemn without losing the atmosphere. In recent years, with the progress of materials, forms, and construction techniques, architectural designers and construction units have gained wide popularity. Meanwhile, under the new trend that the country greatly promotes the housing industrialization, assembly enterprises all over the country come along with the move, and construction enterprises gradually begin to accept the superiority brought by the assembly type components compared with the traditional cast-in-place mode. The clear water assembled component is the development direction of the component, is also the representative of the technical strength of assembly enterprises, and more accords with the popularization concept of high-end and customization of the assembled component. The white bare concrete is novel bare concrete, and due to the particularity of materials, the white bare concrete not only meets the requirements of structural bearing capacity and the like, but also has strict requirements of uniform color and luster and ordered concrete texture decoration function, and has high research and application values.

The white fair-faced concrete is prepared by taking white portland cement as a main cementing material and assisting other white or light-colored materials, and the white portland cement and the gray portland cement have large differences in raw materials, production process and mineral content and generally show the aspects of shrinkage, crack resistance, adaptability with a water reducing agent and the like, so the white fair-faced concrete is less applied to main parts of important structures and is widely used in non-bearing decorative members in the field of assembly. In the other direction, the white fair-faced effect is greatly influenced by raw materials and a production process, the defects of color difference, surface texture and the like are not easy to control, the pseudo fair-faced effect is more common, and the high material cost is beyond the common fair-faced concrete. Moreover, the assembled member concrete is different from the traditional cast-in-place concrete, the number of thin-wall members is large, the number of embedded wall members is large, the requirements on the concrete performance partially depend on the characteristics of equipment, and the characteristics of high early strength (demoulding for 12-16 hours is more than 15 MPa), high thixotropy, quick setting, low shrinkage, high crack resistance, thick viscosity and non-stick property are generally expressed, so that how to solve the unified body of the contradictions is a difficult point to be solved in the preparation technology of the white fair-faced concrete.

Patent CN201910890044 provides fair-faced concrete with good fluidity and a preparation method thereof, and even and stable-adjusting components (diatomite, fibers and rubber powder) are added, but the amount of white cement is too high and is mixed with other varieties of cement for use, so that the structural concrete has a large durable risk when used, and in addition, the patent adds a high amount of fly ash, so that the whiteness of the product is influenced and chromatic aberration is easy to generate; patent CN201210098596 provides a composition for preparing white facing clear water concrete doped with slag powder, and although a whitening means is introduced to improve the whiteness of the product, the product is still slightly yellow after being hardened by using common yellow sand, the whiteness is not enough, in addition, the 1h slump loss of the invention is close to 60mm, the actual constructability is poor, and meanwhile, the concrete has no technical measures of uniformity control or stability regulation under a large flow state, and the color difference is difficult to guarantee. At present, the domestic white fair-faced concrete is difficult to meet the high standard requirements of one-step forming and later repair-free of the fair-faced concrete in both material and production processes. The structure of non-decorative hanging plates in the field of assembly members is rarely reported by white fair-faced concrete members, and is mostly finished by later-stage color matching repair. In order to obtain a good clear water effect, the key point is to control the homogeneity of the whole process of concrete preparation and construction, different component structures need different fluidity matching, meanwhile, the concrete performance needs to be matched with the vibration characteristic of equipment, and the comprehensive characteristic of the concrete can be flexibly adjusted according to the equipment and the process.

Disclosure of Invention

The invention aims to solve the problems and provides white fair-faced concrete for an assembled member and a preparation method thereof, so that white fair-faced concrete with the grade of C35-C50, light white, and the high whiteness requirement of beige is obtained, the surface of the concrete is flat, fine and smooth, the color is uniform, the color is basically consistent, secondary decoration is not needed, and no production equipment is needed to be modified or added, so that the white fair-faced concrete has actual production operability and popularization value.

In order to solve the technical problems, the invention adopts the following technical scheme:

the white clear water finish concrete for the fabricated member comprises the following components in parts by weight: 300-370 kg of cement, 50-130 kg of admixture, 820-950 kg of coarse aggregate, 730-980 kg of fine aggregate, 0.057-15 kg of homogeneity regulator, 5-13 kg of water reducer, 150-170 kg of water, 0-32 kg of titanium dioxide, and 2320-2400 kg/m of total concrete volume weight³(ii) a Wherein:

the admixture is at least one of mineral powder or zeolite powder;

the homogeneity regulator is at least one of limestone powder, superfine calcium carbonate, recovered slurry powder and cellulose ether;

the fine aggregate is dolomite sand, reclaimed water washed river sand or yellow sand.

According to the scheme, the cement is white cement or grey cement, the white cement is white P.W 42.5 cement with I-level whiteness, and the grey cement is P.O 42.5 cement; wherein:

when the cement is white cement, each cubic concrete comprises the following components in parts by weight: 330-360 kg of white cement, 50-120 kg of admixture, 820-900 kg of coarse aggregate, 830-980 kg of fine aggregate, 0.057-13 kg of homogeneity regulator, 5-10 kg of water reducer, 150-170 parts of water and 0-5 kg of titanium dioxide;

when the cement is cement mortar, each cubic concrete comprises the following components in parts by weight: 300-370 kg of gray cement, 50-130 kg of admixture, 850-950 kg of coarse aggregate, 730-910 kg of fine aggregate, 0.069-10 kg of homogeneity regulator, 7.8-13 kg of water reducer, 150-170 kg of water and 19-32 kg of titanium dioxide.

According to the scheme, the initial setting time of the cement is not more than 4 hours, the final setting time is not more than 6 hours, the water consumption for the standard consistency is not more than 28 percent, and the compressive strengths of the 3d mortar and the 28d mortar are not less than 28MPa and 48MPa respectively.

According to the scheme, the mineral powder is S95 grade, the whiteness is more than 90%, and the zeolite powder is clinoptilolite or mordenite for 325-mesh concrete, and the whiteness is more than 75%.

According to the scheme, the limestone powder is 325 meshes; the superfine calcium carbonate is 1250 meshes; the cellulose ether is low-viscosity water-soluble cellulose ether of 20000-200000 mPa-s.

According to the scheme, the recovered slurry powder is powder obtained by precipitating, drying, grinding and sieving fresh waste water obtained by processing excess concrete by a sand-stone separator through a 0.3mm sieve, and the recovered slurry powder is light grey white in color and has potential hydration activity. The residual concrete is the residual concrete which is not solidified in the production process of the member or the residual concrete in the equipment.

According to the scheme, the fineness modulus of the fine aggregate is 2.5-3.0, and the mud content is less than or equal to 2.0%; the recycled washed river sand is obtained by washing excess concrete with slurry, separating and sieving with a 4.75mm sieve, wherein the slurry water is the circulating wastewater of the excess concrete after being treated by a separator.

According to the scheme, the coarse aggregate is any one of dolomite or light-colored crushed stone with the grain diameter of less than 20mm, the gradation is continuous, the mud content is less than or equal to 1.0 percent, the crushing index is less than or equal to 13 percent, and the needle sheet content is less than or equal to 5 percent. Wherein the light colored macadam is light cyan, gray, or light gray.

According to the scheme, the water reducing agent is a polycarboxylic acid water reducing agent for the component, and the water reducing rate of the concrete is more than 28 percent; the whiteness of the titanium dioxide is more than or equal to 98 percent, and the purity is more than 90 percent.

According to the scheme, each cubic concrete further comprises 0.5-1 kg of polypropylene fibers to improve the toughness and the crack resistance of the concrete, and the length of each polypropylene fiber is 9-19 mm.

A preparation method of the white clear water finish concrete for the fabricated member comprises the following steps:

1) determining the mixing ratio of each material in the white clear water finish concrete for the fabricated member;

2) sequentially adding fine aggregate, coarse aggregate, cement, an admixture, a homogeneity regulator (except cellulose ether) and titanium dioxide into a stirrer for premixing for 30-60 s, and uniformly stirring;

3) then, adding water and a water reducing agent together, stirring for 60-90 s, and pre-dissolving cellulose ether into water in advance when the cellulose ether needs to be added;

4) and obtaining the white clear water finish concrete after the blending is finished.

Furthermore, the concrete is suitable for mechanical vibration molding on a mold table, and the vibration mode is shaking screen vibration or small-amplitude high-frequency vertical vibration.

The invention provides white clear water finish concrete for an assembled member, which comprises white cement or ash cement, an admixture, coarse aggregate, fine aggregate, titanium pigment, a homogeneity regulator, tap water and a water reducing agent. In the invention, mineral powder and zeolite powder are introduced as admixture in the aspect of controlling hydration heat and shrinkage. The whiteness of the mineral powder is higher than that of the two types of cement, under the condition of reasonable mixing amount, the obvious short-term green spots are not generated, the early strength is favorably exerted, and meanwhile, the quality and the components of the mineral powder are more stable than those of the fly ash, so that the generation of color difference is further reduced; the zeolite powder is white, has activity second to the micro-silica fume, has excellent effect of improving strength, more importantly, has a grid-shaped structure, uniform holes and channels in the zeolite powder, has a large specific surface area, can adsorb a large amount of water molecules and gas, is balanced with atmospheric relative humidity, increases the viscosity of concrete, improves the slurry wrapping property and the water retention property, effectively improves the bleeding property of the concrete, and improves the homogeneity and the stability of the concrete.

The homogeneity regulator provided by the invention comprises one or more of limestone powder, superfine calcium carbonate, recycled slurry powder and cellulose ether with specific components. Limestone powder and superfine calcium carbonate are not complete inert materials, so that a better micro-aggregate effect and a better dispersion effect can be achieved, a concrete structure is more compact, the appearance is finer and finer due to the refined slurry, the color difference is reduced, the limestone powder and the superfine calcium carbonate can participate in hydration at the later stage to play a certain reinforcing role, and more importantly, a certain anti-settling effect can be achieved, the bleeding is reduced, and the homogeneity and the stability of the concrete are improved; the recycled slurry powder consists of a plurality of hydrated or incompletely hydrated gelled powder particles, fine sand particles and trace mud particles, has fine particles, good whiteness and potential hydration activity, not only plays a better role of filling, but also can obviously improve the performance of concrete slurry, and is favorable for the appearance of a clear water surface and the strength of the concrete under a reasonable mixing amount; the cellulose ether has obvious water-retaining thickening effect, improves the softness of concrete, is easy for material distribution and paving construction, but can influence slump retaining and strength to a certain extent due to excess. If the materials are used independently, the materials have better uniformity adjusting effect, the matching use effect is better, particularly under the condition of poor aggregate gradation, the improvement effect on the workability of concrete is more obvious, and the materials are excellent additives for preparing the high-fluidity fair-faced concrete.

The recycled washed river sand provided by the invention is obtained by washing excess concrete with slurry, separating and sieving with a 4.75mm sieve, and slurry powder particles are adhered to the surfaces of the sand particles, so that the sand is white in whole color, and the recycled washed river sand is a high-quality green environment-friendly material for preparing white finish concrete with high whiteness requirements by replacing or matching with dolomite sand and yellow sand, and can effectively solve the problems of poor integral gradation, poor particle shape, high powder content and high cost of the source mine field dolomite sand.

The white bare concrete taking the white cement as the main cementing material provided by the invention has a mixing proportion, and the color is beige or milky white, so that the grade of PANTONG TPX version PANTONE 11-4201TPX is reached, and the cost is lower; the white fair-faced concrete taking the gray cement as the main cementing material has light white color, reaches the C grade of PANTONE C edition PANTONE 663, has higher whiteness and lower cost, does not need to transform or add production equipment, and has actual production operability and popularization value.

The invention has the beneficial effects that:

1. the white fair-faced concrete for the assembled member can be prepared into white fair-faced concrete with the C35-C50 grade light white and the high whiteness requirement above beige, the surface of the concrete is flat, fine and smooth, the color is uniform and basically consistent, secondary decoration is not needed, production equipment does not need to be transformed or added, and the white fair-faced concrete has actual production operability and popularization value.

2. The cement in the formula is less, compared with the requirement of high early strength of a member, the concrete has the characteristics of lower hydration heat and lower shrinkage performance, the admixture and the homogeneity regulator are matched, the homogeneity and stability of the concrete are greatly improved, and the coarse aggregate and the fine aggregate are cooperated, so that the obtained concrete has flexible and adjustable fluidity, good homogeneity and delamination resistance, small slump loss, strong texture, basically uniform and consistent color, few air holes and little color difference; the requirement that the member concrete can achieve the rapid demoulding of more than 15MPa within 16 hours under the slump (200 +/-20 mm) can be met under the environment of the average temperature of more than 30 ℃.

3. The invention can use the recycled washed river sand or recycled slurry powder, changes waste into valuable, realizes resource recycling, is green and environment-friendly and has lower cost.

Drawings

FIG. 1 is an appearance of a milky white member formulated in example 2 of the present invention.

FIG. 2 is a graphical representation of the appearance of a pale member formulated in example 8 of the present invention.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention.

In the following examples, the following raw material parameters were used:

the cement is gray P.O 42.5 or white P.W 42.5 with grade I whiteness, the initial setting time of the cement is not more than 4 hours, and the final setting time is not more than 6 hours. The water consumption of the cement with the standard consistency is less than or equal to 28 percent, and the compressive strengths of the mortar with the standard consistency of 3d and 28d are not less than 28MPa and 48MPa respectively.

The admixture is one or two of mineral powder and zeolite powder, the mineral powder is S95 grade, the whiteness is more than 90%, the zeolite powder is clinoptilolite or mordenite for 325 mesh concrete, and the whiteness is more than 75%.

The homogeneity regulator is one or more of limestone powder, superfine calcium carbonate, recovered slurry powder and cellulose ether. The limestone powder is 325 meshes, the superfine calcium carbonate is 1250 meshes, the cellulose ether is low-viscosity water-soluble cellulose ether of 150000mPa & s, the recovered slurry powder is obtained from fresh waste water obtained by processing residual concrete through a sand-stone separator, and the recovered slurry powder is powder obtained by precipitation, drying, grinding and sieving by 0.3mm, is light and grey in color and has potential hydration activity.

The coarse aggregate is dolomite or gray limestone broken stone with the grain diameter of less than 20mm, the gradation is continuous, the mud content is less than or equal to 1.0 percent, the crushing index is less than or equal to 13 percent, the needle sheet content is less than or equal to 5 percent, the grain diameter of the dolomite is 5-20 mm, and the grain diameter of the gray limestone broken stone is 5-16 mm.

The fine aggregate is any one of dolomite sand, reclaimed water washing river sand and yellow sand, and the mud content is less than or equal to 2.0 percent; the fineness modulus of the yellow sand is 2.5, and the fineness modulus of the dolomite sand and the washed river sand is 2.8; the reclaimed water washed river sand is obtained after the excess concrete is washed by slurry water, separated and sieved by a 4.75mm sieve, wherein the slurry water is the circulating wastewater of the excess concrete after being treated by a separator.

The water reducing agent is a polycarboxylic acid water reducing agent for the member, and the water reducing rate of the concrete is more than 28 percent.

The whiteness of the titanium dioxide is more than or equal to 98 percent, and the purity is more than 90 percent.

The length of the polypropylene fiber is 9-19 mm.

Examples 1 to 4 are C35 white fair-faced concretes using white P.W 42.5 cement as main cementing material, and the concrete mixing ratio is shown in Table 1, and the unit of each component is kg/m³The water reducing agents used are the same.

TABLE 1

Examples 5 to 7 are C40 to C50 white fair-faced concretes using white P.W 42.5 cement as a main cementing material, and the concrete mixing ratio is shown in Table 2, and the unit of each component is kg/m³The water reducing agents used are the same.

TABLE 2

Examples 8 to 12 are C35 to C50 white fair-faced concretes using gray P.O 42.5 cement as a main cementing material, and the concrete mixing ratio is shown in Table 3, and the units of all the components are kg/m³The water reducing agents used are the same.

TABLE 3

The appearance and strength of the above examples 1 to 12 are shown in Table 4.

TABLE 4

As can be seen from Table 4, white clear water finish concrete members with ideal appearance can be prepared by utilizing the mixing ratios provided by the examples 1 to 12, wherein the colors of the examples 1 to 5 reach the PANTON color card TPX version PANTONE 11-4201TPX level, the colors of the examples 8 to 12 reach the PANTON color card C version PANTONE 663C level, the rapid demoulding requirement of 15MPa within 16 hours is met, and the strength in 28 days is relatively high. Meanwhile, the addition of the polypropylene fiber simultaneously improves the crack resistance of the member and has no obvious influence on the appearance. The thin-wall member made by the above embodiments is a laminated plate or a laminated shear wall, the thickness of a single-side plate is 50-60 mm, advanced equipment is used for automatic material distribution and forming, in order to realize the apparent consistency of the two sides of the member and the surface of the member, the sand ratio is properly enlarged compared with the conventional fair-faced concrete in the mixing proportion, the uniform color and luster are effectively ensured under the proper vibration process, and the defect generation is effectively controlled.

Similarly, based on the technical scheme of the above embodiment, the colored clear water finish concrete can be prepared by adjusting the blending amount or blending the toner with other iron oxide concrete toners.

The above examples are only for illustrating the technical solutions of the present invention and are not limited, and those skilled in the art can make changes and modifications to the technical solutions without departing from the technical solutions and formulation ideas of the present invention, and also fall into the protection scope of the present invention.

Claims (10)

1. A white clear water finish concrete for fabricated members, characterized in that each cubic concrete comprises the following weightThe components by weight: 300-370 kg of cement, 50-130 kg of admixture, 820-950 kg of coarse aggregate, 730-980 kg of fine aggregate, 0.057-15 kg of homogeneity regulator, 5-13 kg of water reducer, 150-170 kg of water, 0-32 kg of titanium dioxide, and 2320-2400 kg/m of total concrete volume weight³(ii) a Wherein:

the admixture is at least one of mineral powder or zeolite powder;

the homogeneity regulator is at least one of limestone powder, superfine calcium carbonate, recovered slurry powder and cellulose ether;

the fine aggregate is dolomite sand, reclaimed water washed river sand or yellow sand.

2. The white clear water finished concrete for fabricated parts according to claim 1, wherein the cement is white cement or grey cement, the white cement is white P.W 42.5 cement of I-grade whiteness, and the grey cement is P.O 42.5 cement; wherein:

when the cement is white cement, each cubic concrete comprises the following components in parts by weight: 330-360 kg of white cement, 50-120 kg of admixture, 820-900 kg of coarse aggregate, 830-980 kg of fine aggregate, 0.057-13 kg of homogeneity regulator, 5-10 kg of water reducer, 150-170 parts of water and 0-5 kg of titanium dioxide;

when the cement is cement mortar, each cubic concrete comprises the following components in parts by weight: 300-370 kg of gray cement, 50-130 kg of admixture, 850-950 kg of coarse aggregate, 730-910 kg of fine aggregate, 0.069-10 kg of homogeneity regulator, 7.8-13 kg of water reducer, 150-170 kg of water and 19-32 kg of titanium dioxide.

3. The white clear water finished concrete for fabricated parts according to claim 1, wherein the initial setting time of the cement is not more than 4 hours, the final setting time is not more than 6 hours, the water consumption of the standard consistency is not more than 28%, and the compressive strengths of 3d and 28d mortar are not less than 28MPa and 48MPa respectively.

4. The white clear water-faced concrete for fabricated components according to claim 1, wherein the mineral powder is grade S95, and the whiteness is > 90%; the zeolite powder is clinoptilolite or mordenite for 325-mesh concrete, and the whiteness is more than 75%.

5. The white clear water-finished concrete for fabricated components according to claim 1, wherein the limestone powder is 325 mesh; the superfine calcium carbonate is 1250 meshes; the cellulose ether is low-viscosity water-soluble cellulose ether of 20000-200000 mPa & s; the recovered slurry powder is obtained from fresh waste water obtained after excess concrete is treated by a sand-stone separator, and is subjected to precipitation, drying, grinding and 0.3mm sieving to obtain powder.

6. The white clear water-faced concrete for the fabricated member according to claim 1, wherein the fineness modulus of the fine aggregate is 2.5-3.0, and the mud content is less than or equal to 2.0%; the recycled washed river sand is obtained by washing excess concrete with slurry, separating and sieving with a 4.75mm sieve, wherein the slurry water is the circulating wastewater of the excess concrete after being treated by a separator.

7. The white clear water-faced concrete for fabricated parts according to claim 1, wherein the coarse aggregate is any one of dolomite or light-colored crushed stone having a particle size of less than 20mm, and has a continuous gradation and a mud content of 1.0% or less, a crushing index of 13% or less, and a needle-flake content of 5% or less.

8. The white clear water finish concrete for the fabricated member according to claim 1, characterized in that the water reducing agent is a polycarboxylic acid water reducing agent for the member, and the water reducing rate of the concrete is more than 28%; the whiteness of the titanium dioxide is more than or equal to 98 percent, and the purity is more than 90 percent.

9. The white clear water-finished concrete for fabricated parts according to claim 1, wherein each cubic concrete further comprises 0.5 to 1kg of polypropylene fibers, and the length of the polypropylene fibers is 9 to 19 mm.

10. A method of preparing the white clear water-finished concrete for fabricated structures according to claim 1, comprising the steps of:

1) determining the mixing ratio of each material in the white clear water finish concrete for the fabricated member;

2) sequentially adding fine aggregate, coarse aggregate, cement, an admixture, a homogeneity regulator except cellulose ether and titanium dioxide into a stirrer according to a ratio in sequence, and stirring uniformly for 30-60 s;

3) then, adding water and a water reducing agent together, stirring for 60-90 s, and pre-dissolving cellulose ether into water in advance when the cellulose ether needs to be added;

4) and obtaining the white clear water finish concrete after the blending is finished.

Images