High-strength bare concrete with uniform color and luster and preparation method of high-strength bare concrete

Abstract

The invention discloses high-strength bare concrete uniform in color and luster and a preparation method thereof.The high-strength bare concrete is prepared from a viscosity modifier, a polycarboxylate superplasticizer and active nano-silicon dioxide micro powder, and the viscosity modifier is a cross-linked polyacrylic acid polymer; molecules of the cross-linked polyacrylic acid polymer have a highly branched three-dimensional network structure. A carboxylic acid group in the viscosity modifier can form a strong hydrogen bond with water, so that water molecules are firmly bound in a system, and accurate viscosity regulation and control are realized through hydrogen bond water locking and slurry stabilization so as to control the color influence caused by water waves on the surface of the high-strength fair-faced concrete. The active nano silicon dioxide micro powder and the polycarboxylate superplasticizer act together, so that the overall color difference of the bare concrete is reduced. The method is easy to operate and high in cost performance, and is a simple and efficient method for controlling the apparent quality of the high-strength bare concrete.

Description

Technical Field

[0001] The present invention relates to the technical field of fair-faced concrete preparation, and in particular to high-strength fair-faced concrete with uniform color and a preparation method thereof. Background Art

[0002] Fair-faced concrete refers to a specialty concrete product that is formed in a single step and finished directly on the original concrete surface or after protective treatment with a transparent protective agent. Its surface is smooth and flat, with no noticeable color differences, sharp edges, or damage. High-strength fair-faced concrete, a specialty concrete that combines high strength with high decorative properties, is a key material in contemporary architecture and engineering.

[0003] The cementitious materials in high-strength plain concrete are unevenly distributed during the concrete mixing, pouring, and production processes. Cement and other cementitious materials migrate with the free water in the system, concentrating at specific points, forming discoloration within the high-strength plain concrete. This results in a darker color at certain points. When segregation occurs during the concrete vibration process, the cementitious materials ooze out into the upper layers of the structure along with the free water, causing color differences between the upper and lower layers. To achieve a uniform color for the high-strength plain concrete, secondary processing is typically required to spray-coat the areas with discoloration. However, spraying not only reduces the visual quality of the plain concrete and increases production costs, but also requires periodic surface repairs, increasing maintenance costs. The coating also impedes the concrete's respiration, hindering internal moisture evaporation and shortening its lifespan. Summary of the Invention

[0004] In response to the defects in the prior art, the present application provides a high-strength plain concrete with uniform color and a preparation method thereof, so as to solve the technical problems such as uneven color of the existing high-strength plain concrete.

[0005] In order to achieve the purpose of the above invention, the technical solution provided by the present invention is as follows:

[0006] A high-strength plain concrete with uniform color, wherein the raw materials of the high-strength plain concrete include a viscosity modifier, a polycarboxylate water reducer and active nano-silica powder;

[0007] The viscosity modifier is a cross-linked polyacrylic acid polymer, and the molecules of the cross-linked polyacrylic acid polymer have a highly branched three-dimensional network structure.

[0008] In one embodiment, the mass of the viscosity modifier is 0.2%-0.4% of the mass of the polycarboxylate water reducer.

[0009] In one embodiment, the amount of active nano-silica powder used in each cubic meter of high-strength plain concrete is 20kg-50kg.

[0010] In one embodiment, the polycarboxylate water reducer is a polycarboxylate high performance water reducer.

[0011] In one embodiment, the raw materials of high-strength plain concrete further include cement, mineral powder, fly ash, fine aggregate, coarse aggregate, and water.

[0012] In one embodiment, the fine aggregate is natural medium sand, and the coarse aggregate is fine crushed stone with good particle shape.

[0013] The present application also provides a method for preparing high-strength plain concrete with uniform color, comprising the following steps:

[0014] S1. Mixing a viscosity modifier, a polycarboxylate water-reducing agent, and water and stirring them uniformly to obtain a mixed solution, wherein the viscosity modifier is a cross-linked polyacrylic acid polymer, and the molecules of the cross-linked polyacrylic acid polymer have a highly branched three-dimensional network structure;

[0015] S2. Weigh cement, mineral powder, fly ash, fine aggregate, coarse aggregate, and water, and mix the raw materials with the mixed solution and active nano-silica powder to obtain a mixture;

[0016] S3. After pouring the mixture, fully vibrate it to obtain high-strength plain concrete.

[0017] In one embodiment, the mass of the viscosity modifier in S1 is 0.2%-0.4% of the mass of the polycarboxylate water reducer, and the amount of the active nano-silica powder in each cubic meter of high-strength plain concrete is 20kg-50kg.

[0018] In one embodiment, the polycarboxylate water-reducing agent in S1 is a polycarboxylate high-performance water-reducing agent, the fine aggregate in S2 is natural medium sand, and the coarse aggregate is fine crushed stone with good particle shape.

[0019] Compared with the prior art, this application has at least the following beneficial effects:

[0020] The high-strength plain concrete with uniform color and its preparation method in this application are provided with a viscosity modifier, a polycarboxylic acid water-reducing agent and active nano-silica powder in the raw materials of the high-strength plain concrete. The viscosity modifier is a cross-linked polyacrylic acid polymer with a highly branched three-dimensional network structure. The carboxylic acid group in the viscosity modifier can form a strong hydrogen bond with water, so that the water molecules are firmly bound in the system, so that the concrete can reduce the viscosity at a high shear rate to make it have high fluidity, and maintain a high viscosity stable slurry at a low shear rate. The hydrogen bond water-locking slurry stabilization technology realizes precise viscosity control to control the color effect caused by water marks on the surface of the high-strength plain concrete. At the same time, the active nano-silica powder disperses the cementitious material through the ball effect and the micro-aggregate filling effect, and works together with the polycarboxylic acid water-reducing agent to effectively disperse the cementitious material components at a low water-cement ratio, avoiding black spots caused by uneven dispersion or aggregation of the cementitious material, improving the black spots of the plain concrete, and reducing the overall color difference of the plain concrete.

[0021] This method eliminates the need for secondary processing of high-strength plain concrete. Color control can be achieved by simply adding the appropriate raw materials during the production process, eliminating the need for subsequent surface processing or coating. This method achieves a uniform color for the high-strength plain concrete. Furthermore, this method is simple to operate and offers a high cost-effectiveness ratio, providing a simple and efficient method for controlling the surface quality of high-strength plain concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a photo of the bare concrete obtained in Comparative Example 1 of this application;

[0023] Figure 2 This is a photo of the bare concrete obtained in Comparative Example 2 of this application;

[0024] Figure 3 This is a photo of the bare concrete obtained in Comparative Example 3 of this application;

[0025] Figure 4 This is a photo of the bare concrete obtained in Example 1 of the present application. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the present invention more clearly apparent, the present invention is described below using specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely illustrative and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0027] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0028] It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various information, such information should not be limited to these terms and should not be understood to indicate or imply relative importance. These terms are only used to distinguish information of the same type from each other. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information without departing from the scope of this disclosure. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining."

[0029] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or the internal communication between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0030] The raw materials of the high-strength plain concrete with uniform color in the present invention include a viscosity modifier, a polycarboxylic acid water reducer and active nano-silica powder. The viscosity modifier is a cross-linked polyacrylic acid polymer, and the molecules of the cross-linked polyacrylic acid polymer have a highly branched three-dimensional network structure.

[0031] The viscosity modifier is 0.2%-0.4% of the mass of the polycarboxylate water-reducing agent. The viscosity modifier can be 0.2%, 0.3%, 0.4%, or even 0.25% or 0.35% of the mass of the polycarboxylate water-reducing agent. The amount of active nano-silica powder used per cubic meter of high-strength plain concrete is 20kg-50kg. The amount can be 20kg, 30kg, 40kg, 50kg, or even 25kg, 35kg, or 45kg. The active nano-silica powder appears as a gray or off-white powder, primarily in the form of amorphous, non-crystalline spheres with a smooth surface.

[0032] Polycarboxylate superplasticizer is a high-performance polycarboxylate superplasticizer designed to ensure the visual quality of high-strength plain concrete. High-strength plain concrete is made from cement, mineral powder, fly ash, fine aggregate, coarse aggregate, and water. The fine aggregate is natural medium sand, while the coarse aggregate is finely sized crushed stone.

[0033] The method for preparing the high-strength plain concrete with uniform color comprises the following steps:

[0034] S1. Mixing a viscosity modifier, a polycarboxylate water-reducing agent, and water and stirring them uniformly to obtain a mixed solution, wherein the viscosity modifier is a cross-linked polyacrylic acid polymer, and the molecules of the cross-linked polyacrylic acid polymer have a highly branched three-dimensional network structure;

[0035] S2. Weigh cement, mineral powder, fly ash, fine aggregate, coarse aggregate, and water, and mix the raw materials with the mixed solution and active nano-silica powder to obtain a mixture;

[0036] S3. After pouring the mixture, fully vibrate it to obtain high-strength plain concrete.

[0037] The viscosity modifier in S1 is 0.2%-0.4% of the mass of the polycarboxylate superplasticizer. The active nano-silica powder is used in an amount of 20kg-50kg per cubic meter of high-strength plain concrete. The polycarboxylate superplasticizer is a high-performance polycarboxylate superplasticizer. The fine aggregate in S2 is natural medium sand, and the coarse aggregate is fine crushed stone with a good particle size.

[0038] In order to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with specific implementation methods and comparative examples.

[0039] Comparative Example 1:

[0040] The raw material components of high-strength plain concrete are shown in Table 1. The polycarboxylate water reducer and water are mixed and stirred to obtain a mixed solution. The other raw materials are weighed according to the measurement, and the raw materials and the mixed solution are mixed to obtain a mixture. The mixture is poured and fully vibrated to obtain the high-strength plain concrete of Comparative Example 1. Figure 1 shown.

[0041] Table 1: Comparative Example 1 High-strength plain concrete mix ratio (unit: kg / m 3 )

[0042] water cement Mineral powder fly ash natural sand Fine Stone Polycarboxylate water reducer 135 353 84 63 719 1010 10.50

[0043] Comparative Example 2:

[0044] The raw materials were prepared in the same proportion as in Comparative Example 1, except that a viscosity modifier, which was a cross-linked polyacrylic acid polymer, was added to the original components at a mass ratio of 0.4% of the mass of the polycarboxylate water-reducing agent. The cross-linked polyacrylic acid polymer had a highly branched three-dimensional network structure. The viscosity modifier, polycarboxylate water-reducing agent, and water were uniformly mixed and stirred to obtain a mixed solution. The other raw materials were weighed according to the metered amount, and the raw materials and the mixed solution were uniformly mixed to obtain a mixture. The mixture was poured and then fully vibrated to obtain the high-strength plain concrete of Comparative Example 2. Figure 2 shown.

[0045] Comparative Example 3:

[0046] The raw materials were prepared in the same proportion as in Comparative Example 1, except that active nano-silica powder was added to the original components. The amount of active nano-silica powder used in each cubic meter of high-strength plain concrete was 25 kg. The polycarboxylate water reducer and water were mixed and stirred to obtain a mixed solution. The other raw materials were weighed according to the measurement, and the raw materials, the mixed solution, and the active nano-silica powder were mixed to obtain a mixture. The mixture was poured and then fully vibrated to obtain the high-strength plain concrete of Comparative Example 3. Figure 3 shown.

[0047] Example 1:

[0048] The raw materials are prepared in the same proportion as in Comparative Example 1, except that a viscosity modifier and active nano-silica powder are added to the original components at a mass ratio of 0.4% of the mass of the polycarboxylic acid water-reducing agent. The viscosity modifier is a cross-linked polyacrylic acid polymer, the molecules of which have a highly branched three-dimensional network structure. The amount of active nano-silica powder used in each cubic meter of high-strength plain concrete is 25 kg. The viscosity modifier, polycarboxylic acid water-reducing agent, and water are mixed and stirred to obtain a mixed solution. Cement, mineral powder, fly ash, fine aggregate, coarse aggregate, and water are weighed and the raw materials are mixed with the mixed solution and active nano-silica powder to obtain a mixture. The mixture is poured and vibrated thoroughly to obtain the high-strength plain concrete of the color and luster described in Example 1, as shown in the attached figure. Figure 4 shown.

[0049] From the attached Figure 1 To the attached Figure 4 It can be seen that the high-strength plain concrete obtained in Comparative Example 1 has obvious water marks and color difference; the high-strength plain concrete obtained in Comparative Example 2 has large black spots and a large overall color difference, but the water marks are improved; the high-strength plain concrete obtained in Comparative Example 3 has small black spots and some water marks on the surface of the plain concrete; the high-strength plain concrete obtained in Example 1 has no obvious color spots and water marks, has good apparent quality, uniform color and no obvious defects. The comparison of the results of the high-strength plain concrete in the sound fields of the comparative example and the example is shown in Table 2.

[0050] Table 2:

[0051] project Water Ripples dark spots Comparative Example 1 obvious obvious Comparative Example 2 Some obvious Comparative Example 3 Some Some Example 1 Not obvious Not obvious

[0052] It can be obtained that when the active nano-silica powder and the viscosity modifier in this application are not added, the apparent quality of high-strength plain concrete is uncontrollable, the obtained high-strength plain concrete has obvious water marks and color difference, and the overall apparent quality is poor; when the viscosity modifier is used, the water marks on the surface of high-strength plain concrete are improved, but there are still obvious black spots on the surface; when the nano-active powder is used alone, the surface color of high-strength plain concrete is improved compared with the blank example, but there are still small areas of color spots, and there are some water marks on the surface of high-strength plain concrete; when the active nano-silica powder and the viscosity modifier are used at the same time, the high-strength plain concrete has no obvious color spots and water marks, the apparent quality is good, the color is uniform and there are no obvious defects. Therefore, the active nano-silica powder and the viscosity modifier have a superimposed technical effect on the improvement of the color of plain concrete. The active nano-silica powder and the viscosity modifier directly have a synergistic promoting effect, which jointly solves the problem of uneven color on the surface of high-strength plain concrete.

[0053] Furthermore, to verify that the introduction of the active nano-silica powder and viscosity modifier of the present invention does not negatively affect the main mechanical properties of high-strength plain concrete, the present invention conducted mechanical property tests on the plain concrete obtained in Comparative Example 1 and Example 1. The test standards were based on GB / T50081-2002 "Test Methods for Mechanical Properties of Ordinary Concrete". The test results are shown in Table 3.

[0054] Table 3:

[0055] project 7d compressive strength / MPa 28d compressive strength / MPa Comparative Example 1 70.9 96.5 Example 1 78.5 107.1

[0056] As can be seen from the compressive strength data in Table 3, the compressive strength of Example 1 is significantly increased compared to that of the blank example, which shows that the introduction of the active nano-silica powder of the present invention and the viscosity modifier found in the present application does not affect the mechanical properties of the high-strength plain concrete, and can also significantly improve the compressive strength.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solutions of the present invention. They should all be included in the scope of the technical solutions for which protection is sought in the present invention.

Claims

1. A high-strength plain concrete with uniform color, characterized in that: The raw materials of high-strength plain concrete include viscosity modifier, polycarboxylate water reducer and active nano-silica powder; The viscosity modifier is a cross-linked polyacrylic acid polymer, and the molecules of the cross-linked polyacrylic acid polymer have a highly branched three-dimensional network structure.

2. The high-strength plain concrete according to claim 1, characterized in that: The mass of the viscosity modifier is 0.2%-0.4% of the mass of the polycarboxylate water reducer.

3. The high-strength plain concrete according to claim 1, characterized in that: The amount of active nano-silica powder used in each cubic meter of high-strength plain concrete is 20kg-50kg.

4. The high-strength plain concrete according to claim 1, characterized in that: The polycarboxylate water reducer is a polycarboxylate high performance water reducer.

5. The high-strength plain concrete according to claim 1, characterized in that: The raw materials of high-strength plain concrete also include cement, mineral powder, fly ash, fine aggregate, coarse aggregate and water.

6. The high-strength plain concrete according to claim 1, characterized in that: The fine aggregate is natural medium sand, and the coarse aggregate is fine crushed stone with good particle shape.

7. A method for preparing high-strength plain concrete with uniform color, characterized in that: The following steps are involved: S1. Mixing a viscosity modifier, a polycarboxylate water-reducing agent, and water and stirring them uniformly to obtain a mixed solution, wherein the viscosity modifier is a cross-linked polyacrylic acid polymer, and the molecules of the cross-linked polyacrylic acid polymer have a highly branched three-dimensional network structure; S2. Weigh cement, mineral powder, fly ash, fine aggregate, coarse aggregate, and water, and mix the raw materials with the mixed solution and active nano-silica powder to obtain a mixture; S3. After pouring the mixture, fully vibrate it to obtain high-strength plain concrete.

8. The method for preparing high-strength plain concrete according to claim 7, characterized in that: The mass of the viscosity modifier in S1 is 0.2%-0.4% of the mass of the polycarboxylate water reducer, and the amount of the active nano-silica powder used in each cubic meter of high-strength plain concrete is 20kg-50kg.

9. The method for preparing high-strength plain concrete according to claim 7, characterized in that: The polycarboxylate water-reducing agent in S1 is a polycarboxylate high-performance water-reducing agent, the fine aggregate in S2 is natural medium sand, and the coarse aggregate is fine crushed stone with good particle shape.

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