Concrete slurry and method for preparing same, use of concrete and polymer

Abstract

The invention discloses a concrete slurry, comprising: 285 parts by weight of cement, 20-50 parts by weight of fly ash, 613-750 parts by weight of sand, 950-1150 parts by weight of crushed stone, 85-120 parts by weight of slag powder, 4-15 parts by weight of polymer, 20-45 parts by weight of expansion agent and water; wherein the polymer is obtained by polymerization reaction of raw materials including isopentanol polyoxyethylene ether, acrylic acid and γ-aminopropyl triethoxysilane; the number average molecular weight of the isopentanol polyoxyethylene ether is 2100-2800, and the molar ratio of the isopentanol polyoxyethylene ether, acrylic acid and γ-aminopropyl triethoxysilane is 1:(3-6):(0.05-0.5). The concrete slurry has less hydration heat release and a slower hydration heat release rate.

Description

Technical Field

[0001] The invention relates to concrete slurry and a preparation method thereof, and uses of concrete and a polymer. Background Art

[0002] Mass concrete refers to large-volume concrete with a minimum geometric dimension of not less than 1m, or concrete that is expected to cause harmful cracks due to temperature changes and shrinkage caused by hydration of cementitious materials in concrete. The concrete used in highway tunnels has a high strength grade and a large amount of cement. The hydration heat must be strictly controlled during the maintenance process, and the temperature difference between the inside and outside should not exceed 25°C. However, in actual projects, the inside and outside temperature of the core area of ​​mass concrete can reach 50°C during the hydration process, far exceeding the 25°C specified in the specification. The tensile stress generated by the large inside and outside temperature difference of concrete exceeds the tensile strength of the concrete itself, making mass concrete prone to cracks.

[0003] CN116063049A discloses a concrete comprising 390-410 parts by weight of cement, 10-50 parts by weight of fly ash, 840-900 parts by weight of sand, 800-830 parts by weight of crushed stone, 50-150 parts by weight of slag powder, 100-200 parts by weight of water, 10-20 parts by weight of a water reducing agent and 15-25 parts by weight of an expansion agent. The concrete has a high hydration heat and has large cracks after being made into a large volume of mixed soil.

[0004] CN115417648A discloses a method for preparing erosion-resistant mass concrete, wherein the raw materials used in the method include 210-300 parts of cement, 900-1050 parts of crushed stone, 680-800 parts of machine-made sand, 35-55 parts of Class II fly ash, 35-55 parts of S95 slag powder, 30-60 parts of heavy calcium powder (200 mesh), 30-60 parts of heavy calcium powder (400 mesh), 30-60 parts of heavy calcium powder (600 mesh), 7.1-14.2 parts of fiber, 3.7-5.7 parts of slow-setting polycarboxylate water-reducing agent, and 160-175 parts of water. The above scheme does not disclose the specific components of the polycarboxylate water-reducing agent. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a concrete slurry, which has less hydration heat release and a slower hydration heat release rate. Furthermore, the concrete slurry has good crack resistance. Furthermore, the concrete slurry of the present invention has higher strength after curing and molding. Another object of the present invention is to provide a method for preparing concrete slurry. Another object of the present invention is to provide concrete. Another object of the present invention is to provide a use of a polymer.

[0006] The above purpose is achieved through the following technical solutions.

[0007] In one aspect, the present invention provides a concrete slurry comprising: 285 parts by weight of cement, 20-50 parts by weight of fly ash, 613-750 parts by weight of sand, 950-1150 parts by weight of crushed stone, 85-120 parts by weight of slag powder, 4-15 parts by weight of polymer, 20-45 parts by weight of expansion agent and water;

[0008] The polymer is obtained by polymerization reaction of raw materials including isopentanol polyoxyethylene ether, acrylic acid and γ-aminopropyltriethoxysilane; the number average molecular weight of the isopentanol polyoxyethylene ether is 2100-2800, and the molar ratio of the isopentanol polyoxyethylene ether, acrylic acid and γ-aminopropyltriethoxysilane is 1:(3-6):(0.05-0.5).

[0009] According to the concrete slurry of the present invention, preferably, the raw materials are polymerized in the presence of 3-mercaptopropionic acid, and the 3-mercaptopropionic acid accounts for 1 to 4% of the mass of the raw materials.

[0010] According to the concrete slurry of the present invention, preferably, the raw materials are polymerized in the presence of vitamin C and water.

[0011] According to the concrete slurry of the present invention, preferably, the polymer is provided by a liquid containing the polymer, and the polymer-containing liquid is prepared by the following method:

[0012] (A) providing a first mixed solution containing prenol polyoxyethylene ether, acrylic acid, γ-aminopropyltriethoxysilane and water and a second mixed solution containing 3-mercaptopropionic acid and vitamin C;

[0013] (B) adding the second mixed solution dropwise to the first mixed solution, and then reacting at 20-38° C. to obtain a reaction product; adjusting the pH of the reaction product to 6.5-8 to obtain a polymer-containing liquid.

[0014] According to the concrete slurry of the present invention, preferably, the expansion agent is polypropylene fiber; the cement is silicate cement, and the compressive strength of the cement after curing for 28 days is greater than or equal to 38MPa; the fly ash is secondary fly ash; the specific surface area of ​​the slag powder is 400-420m 2 / kg; the particle size of the crushed stone is 5 to 30 mm.

[0015] In another aspect, the present invention provides a method for preparing the above concrete slurry, comprising the following steps:

[0016] (1) Cement, fly ash, sand, crushed stone and slag powder are stirred and mixed at a rotation speed of 300 to 700 rpm for 1 to 10 minutes to obtain a mixture;

[0017] (2) The mixture, water, expansion agent and polymer are stirred and mixed at a rotation speed of 700 to 1500 rpm for 0.5 to 5 minutes to obtain concrete slurry.

[0018] In another aspect, the present invention provides a concrete obtained by pouring the above concrete slurry into a mold and curing it.

[0019] On the other hand, the present invention provides a use of a polymer in reducing and / or delaying the heat release of concrete hydration, characterized in that the polymer is obtained by polymerization reaction of raw materials including isopentanol polyoxyethylene ether, acrylic acid and γ-aminopropyltriethoxysilane; the number average molecular weight of the isopentanol polyoxyethylene ether is 2100-2800, and the molar ratio of the isopentanol polyoxyethylene ether, acrylic acid and γ-aminopropyltriethoxysilane is 1:(3-6):(0.05-0.5).

[0020] According to the use of the present invention, preferably, the concrete includes 285 parts by weight of cement, 20-50 parts by weight of fly ash, 613-750 parts by weight of sand, 950-1150 parts by weight of crushed stone, 85-120 parts by weight of slag powder, 20-45 parts by weight of expansion agent and water; the amount of the polymer is 4-15 parts by weight.

[0021] According to the use of the present invention, preferably, the raw material is polymerized in the presence of 3-mercaptopropionic acid, and the 3-mercaptopropionic acid accounts for 1 to 4% of the mass of the raw material.

[0022] A specific polymer is added to the concrete slurry of the present invention, and the polymer cooperates with other components in the concrete slurry to reduce the hydration heat and heat release rate during the curing process. This can reduce the temperature difference between the center and the surface of the concrete, form a large volume of concrete, and improve the crack resistance of the concrete. In addition, the concrete slurry of the present invention has a higher compressive strength after curing. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0024] <Concrete slurry>

[0025] The concrete slurry of the present invention comprises: cement, fly ash, sand, crushed stone, slag powder, polymer, expansion agent and water. In certain embodiments, the concrete slurry consists of the above ingredients.

[0026] The content of cement is 285 parts by weight. The cement may be silicate cement. The compressive strength of the cement after curing for 28 days is greater than or equal to 38 MPa; preferably, greater than or equal to 42 MPa. According to one embodiment of the present invention, the cement is silicate cement PO42.5.

[0027] The content of fly ash is 20 to 50 parts by weight, preferably 25 to 40 parts by weight, and more preferably 30 to 33 parts by weight. The fly ash may be secondary fly ash.

[0028] The content of sand is 613 to 750 parts by weight, preferably 650 to 730 parts by weight, and more preferably 700 to 710 parts by weight. According to one embodiment of the present invention, the content of sand is 702 parts by weight.

[0029] The content of crushed stone is 950 to 1150 parts by weight, preferably 1000 to 1100 parts by weight, and more preferably 1050 to 1053 parts by weight. The particle size of crushed stone can be 5 to 30 mm.

[0030] The content of slag powder is 85 to 120 parts by weight, preferably 90 to 115 parts by weight, and more preferably 95 to 101 parts by weight. The specific surface area of ​​slag powder can be 400 to 420 m 2 / kg.

[0031] The content of the expansion agent may be 20 to 45 parts by weight, preferably 25 to 40 parts by weight, and more preferably 30 to 33 parts by weight. The expansion agent may be polypropylene fiber.

[0032] The water content may be 140 to 220 parts by weight, preferably 150 to 200 parts by weight, and more preferably 170 to 180 parts by weight. According to one embodiment of the present invention, the water content is 176 parts by weight.

[0033] The content of the polymer may be 4 to 15 parts by weight, preferably 5 to 10 parts by weight, and more preferably 6 to 7 parts by weight. According to one embodiment of the present invention, the content of the polymer is 6.2 parts by weight.

[0034] By controlling the content of each component within the above-mentioned range, the hydration heat release and hydration heat release rate of the concrete can be reduced, and the resulting concrete has good crack resistance and strength.

[0035] The polymer of the present invention is obtained by polymerization of raw materials including prenol polyoxyethylene ether, acrylic acid and γ-aminopropyl triethoxysilane. In certain embodiments, the monomers involved in the polymerization reaction are composed of prenol polyoxyethylene ether, acrylic acid and γ-aminopropyl triethoxysilane.

[0036] The number average molecular weight of isopentanol polyoxyethylene ether is 2100 to 2800, preferably 2200 to 2600, and more preferably 2300 to 2500. The molecular weight of isopentanol polyoxyethylene ether has an important influence on the hydration heat release and hydration heat release rate of concrete. The molecular weight of isopentanol polyoxyethylene ether within the scope of the present invention can effectively reduce the hydration heat release and hydration heat release rate of concrete, and improve the crack resistance and strength of concrete.

[0037] The molar ratio of isopentanol polyoxyethylene ether to acrylic acid is 1:(3-6); preferably 1:(4-5); more preferably 1:(4.2-4.5). This helps to reduce the hydration heat and hydration heat release rate of concrete and improve the crack resistance and strength of concrete.

[0038] The molar ratio of isopentanol polyoxyethylene ether to γ-aminopropyltriethoxysilane is 1:(0.05-0.5); preferably 1:(0.1-0.4); more preferably 1:(0.2-0.3). This helps to reduce the hydration heat and hydration heat release rate of concrete and improve the crack resistance and strength of concrete.

[0039] In certain embodiments, the raw material is polymerized in the presence of 3-mercaptopropionic acid, wherein the amount of 3-mercaptopropionic acid used is 1-4% of the raw material mass, preferably 2-3% of the raw material mass, and more preferably 2.5-3% of the raw material mass.

[0040] In certain embodiments, the polymerization reaction is carried out in the presence of vitamin C. The amount of vitamin C used is 0.05 to 0.5 parts by weight, preferably 0.1 to 0.4 parts by weight, and more preferably 0.2 to 0.3 parts by weight.

[0041] In certain embodiments, the polymerization reaction is carried out in the presence of water, wherein the amount of water used is 0.5 to 5 parts by weight, preferably 1 to 4 parts by weight, and more preferably 2 to 3 parts by weight.

[0042] The polymerization reaction can be carried out at 20-38°C; preferably, at 25-35°C.

[0043] The polymer in the present invention can be provided by a liquid containing the polymer. The polymer-containing liquid can be prepared by the following method:

[0044] (A) providing a first mixed solution containing prenol polyoxyethylene ether, acrylic acid, γ-aminopropyltriethoxysilane and water and a second mixed solution containing 3-mercaptopropionic acid and vitamin C;

[0045] (B) adding the second mixed solution dropwise to the first mixed solution, and then reacting at 20-38° C. to obtain a reaction product; adjusting the pH of the reaction product to 6.5-8 to obtain a polymer-containing liquid.

[0046] The molecular weight of isopentanol polyoxyethylene ether, the amount of each substance used and the reaction temperature are specifically as described above and will not be repeated here.

[0047] The pH of the reaction product can be adjusted using a NaOH solution. Preferably, the pH of the reaction product is adjusted to 7-8.

[0048] <Method for preparing concrete slurry>

[0049] The preparation method of the concrete slurry of the present invention comprises the following steps: (1) mixing cement, fly ash, sand, crushed stone and slag powder to obtain a mixture; (2) mixing the mixture, water, an expansion agent and a polymer to obtain a concrete slurry. The selection and dosage of each substance are as described above and will not be repeated here.

[0050] In step (1), the stirring and mixing is carried out at a rotation speed of 300 to 700 rpm; preferably, the rotation speed is 400 to 600 rpm.

[0051] In step (1), the stirring and mixing time is 1 to 10 minutes, preferably 2 to 8 minutes, and more preferably 3 to 5 minutes.

[0052] In step (2), the stirring and mixing is carried out at a rotation speed of 700 to 1500 rpm; preferably, the rotation speed is 800 to 1000 rpm.

[0053] In step (2), the stirring and mixing time is 0.5 to 5 minutes, preferably 1 to 2 minutes.

[0054] <Concrete>

[0055] The concrete of the present invention is obtained by pouring the above concrete slurry into a mold and curing it.

[0056] <Uses of polymers>

[0057] The polymer of the present invention can effectively reduce and / or delay the heat release of concrete hydration. Therefore, the present invention provides a use of a polymer in reducing and / or delaying the heat release of concrete hydration.

[0058] The polymer of the present invention is obtained by polymerization of raw materials including prenol polyoxyethylene ether, acrylic acid and γ-aminopropyl triethoxysilane. In some embodiments, the monomers involved in the polymerization reaction are composed of prenol polyoxyethylene ether, acrylic acid and γ-aminopropyl triethoxysilane. The amount and selection of the above monomers and the conditions of the polymerization reaction are specifically as described above and will not be repeated here.

[0059] The polymer can be provided by a liquid containing the polymer. The polymer-containing liquid can be prepared by the following method:

[0060] (A) providing a first mixed solution containing prenol polyoxyethylene ether, acrylic acid, γ-aminopropyltriethoxysilane and water and a second mixed solution containing 3-mercaptopropionic acid and vitamin C;

[0061] (B) adding the second mixed solution dropwise to the first mixed solution, and then reacting at 20-38° C. to obtain a reaction product; adjusting the pH of the reaction product to 6.5-8 to obtain a liquid containing the polymer.

[0062] The preparation method of the polymer-containing liquid is specifically described above and will not be repeated here.

[0063] Concrete includes cement, fly ash, sand, crushed stone, slag powder, polymer, expansion agent and water. The dosage and selection of each component are as described above and will not be repeated here.

[0064] The specific amount of the polymer is as described above and will not be repeated here.

[0065] Here are the raw materials:

[0066] Cement: Portland cement PO 42.5; Fly ash: Secondary fly ash; Specific surface area of ​​slag powder is 400~420m 2 / kg; the particle size of the crushed stone is 5 to 30 mm.

[0067] Preparation Example 1

[0068] (A) 1 part by weight of prenol polyoxyethylene ether with a number average molecular weight of 2400, 4.2 parts by weight of acrylic acid, 0.2 parts by weight of γ-aminopropyl triethoxy silane and 2 parts by weight of water are added to form a first mixed solution. 3-mercaptopropionic acid and vitamin C are added to form a second mixed solution. The amount of 3-mercaptopropionic acid is 2.5% of the total weight of prenol polyoxyethylene ether, acrylic acid and γ-aminopropyl triethoxy silane, and the amount of vitamin C is 0.2 parts by weight.

[0069] (B) adding the second mixed solution dropwise to the first mixed solution for 1 hour; then reacting at 25° C. to obtain a reaction product; adjusting the pH of the reaction product to 7-8 with a 30 wt % NaOH solution to obtain a polymer-containing liquid.

[0070] Comparative Preparation Examples 1 to 2

[0071] Except that the number average molecular weight of isopentanol polyoxyethylene ether is shown in Table 1, the rest is the same as Preparation Example 1.

[0072] Table 1

[0073] Serial number Number average molecular weight of isopentanol polyoxyethylene ether Comparative Preparation Example 1 2000 Comparative Preparation Example 2 3000

[0074] Comparative Preparation Examples 3 to 4

[0075] Except that the amount of acrylic acid used is as shown in Table 2, the rest is the same as Preparation Example 1.

[0076] Table 2

[0077] Serial number Amount of acrylic acid (parts by weight) Comparative Preparation Example 3 1 Comparative Preparation Example 4 9

[0078] Comparative Preparation Examples 5-6

[0079] Except that the amount of γ-aminopropyltriethoxysilane used is as shown in Table 3, the rest is the same as Preparation Example 1.

[0080] Table 3

[0081] Serial number γ-aminopropyltriethoxysilane dosage (parts by weight) Comparative Preparation Example 5 0.01 Comparative Preparation Example 6 1

[0082] Examples 1 to 3

[0083] (1) 285 parts by weight of cement, 33 parts by weight of fly ash, 702 parts by weight of sand, 1053 parts by weight of crushed stone and 101 parts by weight of slag powder were stirred and mixed at a rotation speed of 500 rpm for 5 minutes to obtain a mixture;

[0084] (2) The mixture, 176 parts by weight of water, 33 parts by weight of polypropylene fibers and the polymer-containing liquid obtained in Preparation Example 1 were stirred and mixed at a rotation speed of 900 rpm for 2 minutes to obtain a concrete slurry. The specific amount of the polymer-containing liquid is shown in Table 4.

[0085] Table 4

[0086] Serial number Amount of polymer liquid (parts by weight) Example 1 4.2 Example 2 6.2 Example 3 8.4

[0087] Note: The amount of polymer-containing liquid is based on the mass of the polymer contained in the polymer-containing liquid.

[0088] Comparative Example 1

[0089] Except that no polymer-containing liquid is added, the rest is the same as in Example 1.

[0090] Comparative Examples 2 to 7

[0091] Except that the type of polymer-containing liquid is as shown in Table 5, the rest is the same as Example 1.

[0092] Table 5

[0093]

[0094] Embodiments 4 to 6

[0095] The concrete slurry is added into the membrane and cured to obtain concrete. The concrete slurry used is specifically shown in Table 6.

[0096] Table 6

[0097] Example 4 Example 5 Example 6 Concrete slurry type Example 1 Example 2 Example 3

[0098] Experimental Example 1

[0099] The concrete slurry of the embodiment and the comparative example was put into a mold to obtain a concrete test block; the mold entry temperature was 28°C and the mold size was 400mm×400mm×400mm. The concrete test block was tightly wrapped with plastic wrap and placed in a closed curing box to reduce temperature exchange with the external environment. The temperature of the central area of ​​the concrete test block during curing in the curing box was detected by inserting a temperature sensor into the central area of ​​the concrete test block to obtain the maximum temperature of the concrete test block hydration heat release and the time when the maximum temperature appeared. The results are shown in Table 7.

[0100] Table 7

[0101] Concrete slurry Maximum temperature of hydration exotherm (℃) The time when the maximum temperature occurs Example 1 59.8 13.5 hours after the start of maintenance Example 2 55.2 17 hours after maintenance starts Example 3 57.2 15 hours after the start of maintenance Comparative Example 1 65.3 10 hours after maintenance starts Comparative Example 2 62.4 12 hours after maintenance starts Comparative Example 3 63.7 11 hours after maintenance starts Comparative Example 4 62.8 10 hours after maintenance starts Comparative Example 5 61.4 11.5 hours after maintenance starts Comparative Example 6 64.2 10.2 hours after maintenance started Comparative Example 7 63.0 11 hours after maintenance starts

[0102] It can be seen from Table 7 that the maximum temperature of the concrete slurry of the present invention during hydration heat release is significantly lower than that of the concrete slurry of the comparative example, and the time when the maximum temperature appears is later than that of the concrete slurry of the comparative example, which indicates that the concrete slurry of the present invention can reduce and delay the hydration heat release of concrete.

[0103] Experimental Example 2

[0104] The crack resistance of the embodiments and comparative examples was tested by the concrete early cracking test (flat plate method) in SL / T352-2020, and the specimen size was 600 mm × 600 mm × 63 mm. The maximum crack width of the specimen formed by the concrete slurry of each embodiment and comparative example was observed. The results are shown in Table 8.

[0105] Table 8

[0106] Concrete slurry Maximum crack width (mm) Example 1 0.34 Example 2 0.26 Example 3 0.63 Comparative Example 1 1.58 Comparative Example 2 1.23 Comparative Example 3 1.47 Comparative Example 4 1.13 Comparative Example 5 0.96 Comparative Example 6 1.31 Comparative Example 7 1.28

[0107] Experimental Example 3

[0108] The concrete slurry was prepared into cubic test blocks of 150mm×150mm×150mm. The compressive strength of the test blocks cured for 3 days, 7 days and 28 days was tested by the method specified in the concrete cube compressive strength test in SL / T352-2020. The instrument used was a universal testing machine. The results are shown in Table 9.

[0109] Table 9

[0110] Concrete slurry 3d compressive strength (MPa) 7d compressive strength (MPa) 28d compressive strength (MPa) Example 1 37 42.4 46.7 Example 2 46.5 49.3 50.0 Example 3 42.5 48.2 49.0

[0111] The present invention is not limited to the above-mentioned embodiments. Without departing from the essential content of the present invention, any deformation, improvement and substitution that can be conceived by those skilled in the art shall fall within the scope of the present invention.

Claims

1. A method for preparing concrete slurry, It is characterized in that The steps include: (1) 1 part by weight of prenol polyoxyethylene ether with a number average molecular weight of 2400, 4.2 parts by weight of acrylic acid, 0.2 parts by weight of γ-aminopropyl triethoxy silane and 2 parts by weight of water are added to form a first mixed solution; 3-mercaptopropionic acid and vitamin C are added to form a second mixed solution; the amount of 3-mercaptopropionic acid is 2.5% of the total weight of prenol polyoxyethylene ether, acrylic acid and γ-aminopropyl triethoxy silane, and the amount of vitamin C is 0.2 parts by weight; (2) adding the second mixed solution dropwise to the first mixed solution for 1 hour; then reacting at 25° C. to obtain a reaction product; adjusting the pH of the reaction product to 7 to 8 with a 30 wt % NaOH solution to obtain a polymer-containing liquid; (3) 285 parts by weight of cement, 33 parts by weight of fly ash, 702 parts by weight of sand, 1053 parts by weight of crushed stone and 101 parts by weight of slag powder were stirred and mixed at a rotation speed of 500 rpm for 5 minutes to obtain a mixture; (4) The mixture, 176 parts by weight of water, 33 parts by weight of polypropylene fibers and 6.2 parts by weight of a polymer-containing liquid were stirred and mixed at a rotation speed of 900 rpm for 2 minutes to obtain a concrete slurry; the amount of the polymer-containing liquid was calculated based on the mass of the polymer contained therein.

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