A concrete rheological preservative and preparation method thereof

Abstract

The invention discloses a method for preparing a concrete rheological preservative. The method comprises, by weight, 8-12 parts of fly ash, 3-4 parts of siloxane, 0.5-0.7 parts of sodium diacetate, 3-5 parts of methacrylic acid, 14-16 parts of alunite, and 8-10 parts of borax. The alunite is calcined at a high temperature and then mixed with the siloxane to prepare a mixture 1. The mixture 1 is mixed with the remaining components and dried to prepare the concrete rheological preservative. The concrete rheological preservative is mixed with concrete raw materials to improve the corrosion resistance, anti-permeability and other properties of the concrete.

Description

Technical Field

[0001] The present invention relates to the field of concrete additives, in particular to a method for preparing a concrete rheological preservative. Background Art

[0002] Saline soil, groundwater, seawater, decayed organic matter and industrial wastewater contain a large amount of sulfate. Sulfate ions penetrate into concrete and react with the hydration products of cement to generate expansive corrosion products, which generate internal stress inside the concrete. When the internal stress exceeds the tensile strength of the concrete, the concrete will crack and peel off, causing the concrete to be destroyed due to loss of strength and bonding properties, and resulting in a reduction in the durability of the concrete structure. It is obviously corrosive to highway bridges, culverts and structures, and constitutes a harsh corrosion environment for the foundations of structures and underground facilities, affecting their durability and safety. Therefore, in some areas, anti-sulfate preservatives are indispensable. Summary of the Invention

[0003] In view of this, the present invention proposes a method for preparing a concrete rheological preservative to solve the above problems.

[0004] A concrete rheology preservative comprises, by weight, 8-12 parts of fly ash, 3-4 parts of siloxane, 0.5-0.7 parts of sodium diacetate, 3-5 parts of methacrylic acid, 14-16 parts of alunite and 8-10 parts of borax.

[0005] Furthermore, the invention comprises, by weight, 10 parts of fly ash, 3.5 parts of siloxane, 0.6 parts of sodium diacetate, 4 parts of methacrylic acid, 15 parts of alunite and 9 parts of borax.

[0006] Furthermore, the alunite is placed in a muffle furnace, heated to 300-350° C. at a rate of 5-6° C. / min, kept warm for 50-70 minutes, cooled with the furnace, and the cooled alunite is crushed to obtain alunite powder.

[0007] Furthermore, the particle size of the alunite powder is 200 mesh.

[0008] Furthermore, the preparation method of the concrete rheological preservative comprises the following steps:

[0009] (1) placing alunite powder and siloxane into a ball mill with steel balls as the milling medium to prepare a mixed material 1;

[0010] (2) Mixing the mixed material 1, fly ash, sodium diacetate, methacrylic acid, borax and water to prepare a mixed material 2;

[0011] (3) Dry the mixture 2 to obtain a finished product.

[0012] Furthermore, in step (1), the ball milling speed is 20-25 r / min, and the ball milling time is 100-120 min.

[0013] Furthermore, in step (2), the amount of water added is 10-15% of the total mass of the mixed material 1, fly ash, sodium diacetate, methacrylic acid, and borax.

[0014] Furthermore, in step (3), the drying temperature is 130-150° C., and the drying time is 4-5 hours.

[0015] Furthermore, in step (1), the siloxane is one of methyl epoxy siloxane, n-butyl epoxy siloxane, and fluorocarbon siloxane.

[0016] Beneficial effects of the present invention:

[0017] The present invention uses fly ash, siloxane, sodium diacetate, methacrylic acid, alunite and borax as raw materials, and improves the performance of the concrete rheological preservative by rationally proportioning the components. The concrete rheological preservative of the present invention can reduce the chloride ion penetration rate and improve the compressive strength of concrete. The raw materials of the present invention can penetrate into the interior of concrete and fill the concrete pores and microcracks, thereby reducing the permeability and water permeability of the concrete surface, achieving a waterproof effect. A dense fatty acid salt layer is formed on the concrete surface, and an aluminum oxide layer generated by a chemical reaction is formed, which makes the concrete surface exhibit chemical corrosion resistance. In the present invention, the alunite is first calcined at high temperature and then pulverized. The siloxane and alunite powder are mixed and ball-milled to change the physical properties of the alunite, improve the adsorption capacity of the alunite, and further optimize the alunite powder particle size so that the raw materials fully fill the concrete pores and microcracks. In the present invention, the concrete rheological preservative is prepared by drying at 130-150° C. for 4-5 hours. Reasonable temperature can promote the reaction of raw materials of the concrete rheological preservative and avoid the generation of impurities, which would lead to a decrease in the use effect of the concrete rheological preservative. DETAILED DESCRIPTION

[0018] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0019] Example 1 Preparation method of concrete rheological preservative

[0020] The following raw materials were weighed in parts by weight: 10 parts of fly ash, 3.5 parts of methyl epoxysiloxane, 0.6 parts of sodium diacetate, 4 parts of methacrylic acid, 15 parts of alunite and 9 parts of borax.

[0021] Alunite was placed in a muffle furnace, heated to 330°C at a rate of 5°C / min, kept warm for 60 minutes, and cooled with the furnace. The cooled alunite was crushed to 200 mesh to obtain alunite powder. The alunite powder and methyl epoxysiloxane were placed in a ball mill and milled at a ball milling speed of 203 r / min for 110 minutes using steel balls as the ball milling medium to obtain mixed material 1.

[0022] Mixture 1, fly ash, sodium diacetate, methacrylic acid, borax and water are mixed, with the amount of water added being 13% of the weight of the raw materials, to prepare mixture 2.

[0023] Mixture 2 was dried at 140° C. for 4.5 h to obtain a concrete rheological preservative.

[0024] Example 2 Preparation method of concrete rheological preservative

[0025] The following raw materials were weighed in parts by weight: 10 parts of fly ash, 3.5 parts of n-butyl epoxysiloxane, 0.6 parts of sodium diacetate, 4 parts of methacrylic acid, 15 parts of alunite and 9 parts of borax.

[0026] Alunite was placed in a muffle furnace, heated to 330°C at a rate of 5°C / min, kept warm for 60 minutes, and cooled with the furnace. The cooled alunite was crushed to 200 mesh to obtain alunite powder. The alunite powder and n-butyl epoxysiloxane were placed in a ball mill and milled at a ball milling speed of 203 r / min for 110 minutes using steel balls as the ball milling medium to obtain mixed material 1.

[0027] Mixture 1, fly ash, sodium diacetate, methacrylic acid, borax and water are mixed, with the amount of water added being 13% of the weight of the raw materials, to prepare mixture 2.

[0028] Mixture 2 was dried at 140° C. for 4.5 h to obtain a concrete rheological preservative.

[0029] Example 3 Preparation method of concrete rheological preservative

[0030] The following raw materials were weighed in parts by weight: 10 parts of fly ash, 3.5 parts of fluorocarbon siloxane, 0.6 parts of sodium diacetate, 4 parts of methacrylic acid, 15 parts of alunite and 9 parts of borax.

[0031] Alunite was placed in a muffle furnace, heated to 330°C at a rate of 5°C / min, kept warm for 60 minutes, and cooled with the furnace. The cooled alunite was crushed to 200 mesh to obtain alunite powder. The alunite powder and fluorocarbon siloxane were placed in a ball mill and milled at a ball mill speed of 203 r / min for 110 minutes using steel balls as the ball milling medium to obtain mixed material 1.

[0032] Mixture 1, fly ash, sodium diacetate, methacrylic acid, borax and water are mixed, with the amount of water added being 13% of the weight of the raw materials, to prepare mixture 2.

[0033] Mixture 2 was dried at 140° C. for 4.5 h to obtain a concrete rheological preservative.

[0034] Comparative Example 1 Preparation Method of Concrete Rheological Preservative

[0035] The following raw materials were weighed in parts by weight: 10 parts of fly ash, 0.6 parts of sodium diacetate, 4 parts of methacrylic acid, 15 parts of alunite and 9 parts of borax.

[0036] The alunite was placed in a muffle furnace, heated to 330°C at a rate of 5°C / min, kept warm for 60 minutes, and cooled with the furnace. The cooled alunite was crushed to 200 mesh to obtain alunite powder.

[0037] Alunite powder, fly ash, sodium diacetate, methacrylic acid, borax and water were mixed, with the amount of water added being 13% of the weight of the raw materials, to prepare a mixed material 2.

[0038] Mixture 2 was dried at 140° C. for 4.5 h to obtain a concrete rheological preservative.

[0039] Comparative Example 2 Preparation Method of Concrete Rheological Preservative

[0040] The following raw materials were weighed in parts by weight: 10 parts of fly ash, 3.5 parts of methyl epoxysiloxane, 0.6 parts of sodium diacetate, 4 parts of methacrylic acid, 15 parts of metakaolin and 9 parts of borax.

[0041] Metakaolin and methyl epoxysiloxane were placed in a ball mill and milled at a speed of 20 r / min for 110 min using steel balls as the milling medium to prepare a mixture 1.

[0042] Mixture 1, fly ash, sodium diacetate, methacrylic acid, borax and water are mixed, with the amount of water added being 13% of the weight of the raw materials, to prepare mixture 2.

[0043] Mixture 2 was dried at 140° C. for 4.5 h to obtain a concrete rheological preservative.

[0044] Comparative Example 3 Preparation Method of Concrete Rheological Preservative

[0045] The following raw materials were weighed in parts by weight: 10 parts of fly ash, 3.5 parts of methyl epoxysiloxane, 0.6 parts of sodium diacetate, 4 parts of methacrylic acid, 15 parts of alunite and 9 parts of borax.

[0046] Alunite was placed in a muffle furnace, heated to 330°C at a rate of 5°C / min, kept warm for 60 minutes, and cooled with the furnace. The cooled alunite was crushed to 200 mesh to obtain alunite powder. The alunite powder and methyl epoxysiloxane were placed in a ball mill and milled at a ball milling speed of 203 r / min for 110 minutes using steel balls as the ball milling medium to obtain mixed material 1.

[0047] Mixture 1, fly ash, sodium diacetate, methacrylic acid, borax and water are mixed, with the amount of water added being 13% of the weight of the raw materials, to prepare mixture 2.

[0048] Mixture 2 was dried at 180°C for 6 h to obtain a concrete rheological preservative.

[0049] Test Example 1

[0050] The concrete rheology preservatives prepared in Examples 1-3 and Comparative Examples 1-3 were tested. The concrete was prepared, by weight, from 400 parts cement, 140 parts fly ash, 700 parts fine aggregate, 970 parts coarse aggregate, 9 parts admixtures, and 150 parts water. The admixtures included 25 parts polycarboxylate water reducer, 9 parts slump control agent, 15 parts retarder, and 0.8 parts air entraining agent.

[0051] The control concrete was made from 280 parts cement, 42 parts fly ash, 800 parts sea sand, 650 parts coarse aggregate and 200 parts water.

[0052] The expansion of the slurry at 0h and 1h was tested with reference to the "Standard for Test Methods of Performance of Ordinary Concrete Mixtures" (GB / T 50080-2016).

[0053] Refer to the "Standard for Test Methods for Physical and Mechanical Properties of Concrete" (GBT50081-2019) to test the 28d compressive strength of 100mm cube.

[0054] The rapid chloride ion diffusion coefficient Dncw(28d) of concrete was tested with reference to the Standard for Test Methods for Long-term Properties and Durability of Ordinary Concrete (GB / T 50082-2009).

[0055] Table 1 Concrete expansion test data

[0056] name Example 1 Example 2 Example 3 control group 0h(mm) 490 500 495 505 1h(mm) 525 520 525 525

[0057] The test results show that the concrete rheological preservative of the present invention has no effect on the expansion of concrete, and will not cause the viscosity of concrete to increase or the flow performance to decrease.

[0058] Table 2 Rapid chloride ion diffusion coefficient of concrete (×10 -12 m 2 s -1), compressive strength test data (MPa)

[0059] name Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 28d fast chloride ion diffusion coefficient 1.78 1.82 1.80 3.47 2.84 2.37 28d compressive strength 62.7 60.1 61.5 50.8 53.1 56.9

[0060] The test results show that the concrete rheological preservative of the present invention can reduce the chloride ion penetration rate and improve the compressive strength of concrete. The raw materials of the present invention can penetrate into the interior of the concrete and fill the concrete pores and microcracks, thereby reducing the permeability and water permeability of the concrete surface, achieving a waterproof effect. The concrete surface forms a dense fatty acid salt layer and forms an aluminum oxide layer generated by a chemical reaction, so that the concrete surface presents the characteristics of chemical corrosion resistance. In Comparative Example 1, siloxane is not used. In the present invention, siloxane and alunite are used for mixed ball milling, which can change the physical properties of alunite and improve the adsorption capacity of alunite. In Comparative Example 2, metakaolin is used instead of alunite, causing the performance of the concrete rheological preservative to decline. Comparative Example 3 adjusts the drying method of the concrete rheological preservative. In the present invention, a reasonable reaction temperature is used to promote the reaction of the raw materials of the concrete rheological preservative. Comparative Example 3 uses a higher reaction temperature to generate impurities, further affecting the use effect of the concrete rheological preservative.

[0061] Example 4 Preparation method of concrete rheological preservative

[0062] The following raw materials were weighed in parts by weight: 8 parts of fly ash, 3 parts of methyl epoxysiloxane, 0.5 parts of sodium diacetate, 3 parts of methacrylic acid, 14 parts of alunite and 8 parts of borax.

[0063] Alunite was placed in a muffle furnace, heated to 300°C at a rate of 5°C / min, kept warm for 50 min, and cooled with the furnace. The cooled alunite was crushed to 200 mesh to obtain alunite powder. The alunite powder and methyl epoxysiloxane were placed in a ball mill and milled at a ball mill speed of 20-r / min for 100 min using steel balls as the ball milling medium to obtain mixed material 1.

[0064] Mixture 1, fly ash, sodium diacetate, methacrylic acid, borax and water are mixed, with the amount of water added being 10% by weight of the raw materials, to prepare mixture 2.

[0065] Mixture 2 was dried at 130° C. for 4 h to obtain a concrete rheological preservative.

[0066] Example 5 Preparation method of concrete rheological preservative

[0067] The following raw materials were weighed in parts by weight: 12 parts of fly ash, 4 parts of methyl epoxysiloxane, 0.7 parts of sodium diacetate, 5 parts of methacrylic acid, 4 parts of alunite and 10 parts of borax.

[0068] Alunite was placed in a muffle furnace, heated to 350°C at a rate of 6°C / min, kept warm for 70 minutes, and cooled with the furnace. The cooled alunite was crushed to 200 mesh to obtain alunite powder. The alunite powder and methyl epoxysiloxane were placed in a ball mill and milled at a ball milling speed of 25 r / min for 120 minutes using steel balls as the ball milling medium to obtain mixed material 1.

[0069] Mixture 1, fly ash, sodium diacetate, methacrylic acid, borax and water are mixed, with the amount of water added being 15% by weight of the raw materials, to prepare mixture 2.

[0070] Mixture 2 was dried at 150° C. for 5 h to obtain a concrete rheological preservative.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A concrete rheological preservative, characterized in that: The invention comprises, by weight, 8-12 parts of fly ash, 3-4 parts of siloxane, 0.5-0.7 parts of sodium diacetate, 3-5 parts of methacrylic acid, 14-16 parts of alunite and 8-10 parts of borax; the alunite is placed in a muffle furnace, heated to 300-350°C at a rate of 5-6°C / min, kept at this temperature for 50-70 minutes, cooled with the furnace, and the cooled alunite is crushed to obtain alunite powder; The preparation method of the concrete rheological preservative comprises the following steps: (1) placing alunite powder and siloxane in a ball mill and milling them at a speed of 20-25 r / min for 100-120 min using steel balls as the milling medium to obtain a mixture 1; (2) Mixing the mixed material 1, fly ash, sodium diacetate, methacrylic acid, borax and water, wherein the amount of water added is 10-15% of the total mass of the mixed material 1, fly ash, sodium diacetate, methacrylic acid and borax, to prepare a mixed material 2; (3) drying the mixed material 2 at a temperature of 130-150° C. for 4-5 hours to obtain a finished product; Wherein, the siloxane is one of methyl epoxy siloxane, n-butyl epoxy siloxane or fluorocarbon siloxane.

2. The concrete rheological antiseptic according to claim 1, characterized in that The invention comprises, by weight, 10 parts of fly ash, 3.5 parts of siloxane, 0.6 parts of sodium diacetate, 4 parts of methacrylic acid, 15 parts of alunite and 9 parts of borax.

3. The concrete rheological antiseptic according to claim 1, characterized in that: The particle size of the alunite powder is 200 meshes.