A low-shrinkage high-strength self-compacting concrete and its preparation method

Abstract

The present invention discloses a low-shrinkage high-strength self-compacting concrete and a preparation method thereof, relating to the field of concrete materials. Among them, the self-compacting concrete comprises raw materials such as sulfoaluminate cement, mineral admixture, crushed stone, fine sand, admixture and water. The admixture includes polyether-modified silicone oil, methylene bisnaphthalene sulfonate and polycarboxylate water reducer, and the weight ratio of the polyether-modified silicone oil, methylene bisnaphthalene sulfonate and polycarboxylate water reducer is (2-3):(1-2):1. This self-compacting concrete has the advantages of small dry shrinkage, high strength and good uniformity. The surface of the concrete precast member made of this low-shrinkage self-compacting concrete has no honeycombing and pockmarks.

Description

Technical Field

[0001] The present invention relates to the field of concrete materials, and particularly to a low-shrinkage high-strength self-compacting concrete and a preparation method thereof. Background Art

[0002] Concrete precast components are required to have no quality problems such as honeycombing, pitting, and dry shrinkage cracks. Among them, when producing concrete precast components with ordinary Portland cement, due to the relatively long setting and hardening time of ordinary Portland cement, the production cycle is also relatively long. At present, in order to save the construction period, some manufacturers use sulfoaluminate cement instead of ordinary Portland cement when producing concrete precast components, shortening the hardening and forming time of the concrete and having a shorter production cycle. However, at the same time, some new problems have emerged: there are serious honeycombing, pitting, and dry shrinkage cracks in the concrete precast components.

[0003] To solve the newly emerged problems, some manufacturers have reduced honeycombing and pitting by increasing the amount of sulfoaluminate cement. However, this has further increased the shrinkage rate of the concrete precast components, resulting in many dry shrinkage cracks and low strength in the concrete precast components. Therefore, how to obtain concrete precast components with a short production cycle, no honeycombing, few surface dry shrinkage cracks, and high strength has important research significance. Summary of the Invention

[0004] In order to prepare concrete precast components with a short production cycle, no honeycombing, few surface dry shrinkage cracks, and high strength, the present application provides a low-shrinkage high-strength self-compacting concrete and a preparation method thereof.

[0005] In the first aspect, a low-shrinkage high-strength self-compacting concrete provided by the present application adopts the following technical solution:

[0006] A low-shrinkage high-strength self-compacting concrete, comprising the following raw materials in parts by weight:

[0007] Sulfoaluminate cement: 180 - 200 parts

[0008] Mineral admixture: 220 - 240 parts

[0009] Crushed stone: 950 - 960 parts

[0010] Fine sand: 930 - 940 parts

[0011] Admixture: 8 - 12 parts

[0012] Water: 130 - 140 parts

[0013] The admixture includes polyether-modified silicone oil, methylene bisnaphthalene sulfonate, and polycarboxylate water reducer, and the weight ratio of polyether-modified silicone oil, methylene bisnaphthalene sulfonate, and polycarboxylate water reducer is (2 - 3):(1 - 2):1.

[0014] This application prepares low-shrinkage high-strength self-compacting concrete by using sulfoaluminate cement, mineral admixture, crushed stone, fine sand, admixture and water. Among them, the hardening speed of sulfoaluminate cement is faster than that of ordinary Portland cement, which is beneficial to shortening the production cycle of concrete precast parts. When the admixture is a mixture of polyether-modified silicone oil, methylene bisnaphthalene sulfonate and polycarboxylate water reducer in a specific ratio, the fluidity of the fresh concrete can be adjusted within a suitable range, which can not only ensure that the fresh concrete can obtain concrete with a surface free of honeycombing and pitting and dense inside without vibration, but also effectively reduce the dry shrinkage of the concrete, thereby preventing the generation of dry shrinkage cracks in the concrete precast parts and being beneficial to improving the strength of the self-compacting concrete.

[0015] Optionally, the weight ratio of the polyether-modified silicone oil, methylene bisnaphthalene sulfonate and polycarboxylate water reducer is 2.5:1.5:1.

[0016] When the weight ratio of the polyether-modified silicone oil, methylene bisnaphthalene sulfonate and polycarboxylate water reducer is within the above range, the dry shrinkage of the self-compacting concrete is further reduced and the strength is further improved.

[0017] Optionally, the preparation method of the polyether-modified silicone oil is as follows:

[0018] After mixing 20 parts by weight of allyl alcohol polyoxyalkylene ether and 48-55 parts by weight of hydrogen-containing silicone oil, the temperature is raised to 50-60 °C, and 1-2 parts by weight of a chloroplatinic acid-isopropanol solution with a chloroplatinic acid weight ratio of 0.5 wt% is added. After reacting for 0.5-1 h, 80 parts by weight of allyl alcohol polyoxyalkylene ether is added at a rate of 1-2 g / min, and then the temperature is raised to 100-120 °C and the reaction continues for 2-3 h to obtain polyether-modified silicone oil.

[0019] When the polyether-modified silicone oil is the polyether-modified silicone oil prepared by the above preparation method, it can not only reduce the shrinkage value of the self-compacting concrete, but also reduce the possibility of segregation of the fresh self-compacting concrete, which is beneficial to improving the quality uniformity of the concrete precast parts made of low-shrinkage high-strength self-compacting concrete.

[0020] Optionally, the molecular weight of the allyl alcohol polyoxyalkylene ether is 1400-2000, the viscosity of the hydrogen-containing silicone oil is 20-25 cs, and the hydrogen content is 1.2-1.4%.

[0021] When the parameters of the allyl alcohol polyoxyalkylene ether and the hydrogen-containing silicone oil are within the above range, the possibility of segregation of the fresh self-compacting concrete can be further reduced, which is beneficial to further improving the quality uniformity of the concrete precast parts made of low-shrinkage high-strength self-compacting concrete.

[0022] Optionally, the particle size range of the crushed stone is 5-20 mm.

[0023] Optionally, the grading distribution of the crushed stone is as follows:

[0024] The residue on the 16mm standard sieve accounts for 30% - 40wt%, the residue on the 9.5mm standard sieve accounts for 40% - 60wt%, and the residue on the 4.75mm standard sieve accounts for 10% - 20wt%.

[0025] When the grading of the crushed stone is within the above range, the compactness of the self-compacting concrete can be further improved, and the dry shrinkage of the self-compacting concrete can be reduced.

[0026] Optionally, the particle size grading distribution of the fine sand is as follows:

[0027] The residue on the 4.75mm standard sieve accounts for 1 - 3wt%, the residue on the 2.36mm standard sieve accounts for 20 - 30wt%, the residue on the 1.18mm standard sieve accounts for 40 - 60wt%, and the residue on the 0.6mm standard sieve accounts for 19 - 27wt%.

[0028] When the grading of the fine sand is within the above range, it can cooperate with the grading of the above crushed stone to further effectively improve the compactness and strength of the self-compacting concrete, and at the same time, it can also further improve the quality uniformity of the concrete precast members made of low-shrinkage high-strength self-compacting concrete.

[0029] Optionally, the mineral admixture includes fly ash and phosphorous slag powder, and the weight ratio of fly ash to phosphorous slag powder is (8 - 10):1.

[0030] When the mineral admixture selects the mixture within the above ratio range of fly ash and phosphorous slag powder, it can not only reduce the dry shrinkage of the self-compacting concrete and improve the compactness of the self-compacting concrete, but also effectively improve the quality uniformity of the concrete precast members made of low-shrinkage high-strength self-compacting concrete.

[0031] In the second aspect, a preparation method of the low-shrinkage high-strength self-compacting concrete provided by the present application adopts the following technical solution:

[0032] A preparation method of a low-shrinkage high-strength self-compacting concrete, comprising the following steps:

[0033] Dissolve the admixture in water to obtain an admixture solution;

[0034] Add the sulfoaluminate cement and the mineral admixture into the admixture solution and stir evenly to obtain a cement slurry;

[0035] Add the crushed stone and the fine sand into the cement slurry, and after stirring evenly, obtain the low-shrinkage high-strength self-compacting concrete.

[0036] Using the above method to prepare the low-shrinkage high-strength self-compacting concrete can quickly and evenly mix all raw materials.

[0037] In summary, the technical solution of the present application has at least the following beneficial effects:

[0038] The low-shrinkage self-compacting concrete of the present application has the advantages of small dry shrinkage, high strength, and good uniformity. The concrete precast members made of this low-shrinkage self-compacting concrete have no honeycombing and pitting on the surface, and the standard deviation is small. Specific Embodiments

[0039] The present application will be further described in detail below in conjunction with examples and comparative examples.

[0040] Examples 1-2

[0041] A kind of low-shrinkage high-strength self-compacting concrete, the proportions of each component are as shown in Table 1 below.

[0042] Table 1 Proportions of Low-Shrinkage High-Strength Self-Compacting Concrete in Examples 1-2 (unit / kg)

[0043] Component Example 1 Example 2 Sulfoaluminate cement 180 200 Mineral admixture 240 220 Crushed stone 950 960 Fine sand 940 930 Admixture 8 12 Water 140 130

[0044] In the above Table 1, the performance indicators of the sulfoaluminate cement are as shown in Table 1-1:

[0045] Table 1-1 Performance Indicators of Sulfoaluminate Cement

[0046]

[0047] The mineral admixture is selected as Class II fly ash.

[0048] The particle size range of the crushed stone is 5-20 mm. Among them, the gradation distribution of the crushed stone is as shown in Table 1-2:

[0049] Table 1-2 Gradation Distribution of Crushed Stone

[0050]

[0051] The particle size gradation of the fine sand is as shown in Table 1-3:

[0052] Table 1-3 Particle Size Gradation of Fine Sand

[0053]

[0054] The admixtures include polyether-modified silicone oil, methylene bisnaphthalene sulfonate, and polycarboxylate water reducer. The weight ratio of polyether-modified silicone oil, methylene bisnaphthalene sulfonate, and polycarboxylate water reducer is 2:2:1.

[0055] The polyether-modified silicone oil is selected as commercially available polyether-modified silicone oil 204, and the polycarboxylate water reducer is selected as polycarboxylate water reducer 530P.

[0056] In addition, the preparation method of the low-shrinkage high-strength self-compacting concrete in Examples 1-2 includes the following steps:

[0057] Dissolve the admixture in water to obtain an admixture solution;

[0058] Add sulfoaluminate cement and mineral admixture into the admixture solution and stir evenly to obtain cement paste;

[0059] Add crushed stones and fine sand into the cement paste and stir evenly to obtain low-shrinkage high-strength self-compacting concrete.

[0060] Example 3

[0061] A low-shrinkage high-strength self-compacting concrete, different from Example 1 in that:

[0062] The weight ratio of polyether-modified silicone oil, methylene bisnaphthalene sulfonate and polycarboxylate water reducer is 2.5:1.5:1.

[0063] Example 4

[0064] A low-shrinkage high-strength self-compacting concrete, different from Example 1 in that:

[0065] The weight ratio of polyether-modified silicone oil, methylene bisnaphthalene sulfonate and polycarboxylate water reducer is 3:1:1.

[0066] Example 5

[0067] A low-shrinkage high-strength self-compacting concrete, different from Example 3 in that:

[0068] The polyether-modified silicone oil is selected as self-made polyether-modified silicone oil, and the preparation method of the polyether-modified silicone oil is as follows:

[0069] Mix 100 g of allyl alcohol polyoxyalkylene ether with a molecular weight of 3000 and 52 g of hydrogen-containing silicone oil with a viscosity of 18 cs and a hydrogen content of 1.2%, heat up to 55 °C, and add 1.5 g of chloroplatinic acid-isopropanol solution with a weight ratio of chloroplatinic acid of 0.5 wt%. After reacting for 0.5 h, then heat up to 110 °C and continue to react for 3 h to obtain polyether-modified silicone oil.

[0070] Example 6

[0071] A low-shrinkage high-strength self-compacting concrete, different from Example 5 in that:

[0072] The preparation method of the polyether-modified silicone oil is as follows:

[0073] After mixing 20 g of allyl alcohol polyoxyalkylene ether with a molecular weight of 3000 and 52 g of hydrogen-containing silicone oil with a viscosity of 18 cs and a hydrogen content of 1.2%, the temperature was raised to 55 °C, and 1.5 g of a chloroplatinic acid-isopropanol solution with a weight ratio of chloroplatinic acid of 0.5 wt% was added. After reacting for 0.5 h, 80 parts by weight of allyl alcohol polyoxyalkylene ether was added at 2 g / min. Then the temperature was raised to 110 °C and the reaction was continued for 2 h to obtain polyether-modified silicone oil.

[0074] Example 7

[0075] A low-shrinkage, high-strength, self-compacting concrete, different from Example 6 in that:

[0076] The molecular weight of the allyl alcohol polyoxyalkylene ether is 2000, and the viscosity of the hydrogen-containing silicone oil is 22.

[0077] Example 8

[0078] A low-shrinkage, high-strength, self-compacting concrete, different from Example 1 in that:

[0079] The grading distribution of the crushed stone is as shown in Table 1-4 below.

[0080] Table 1-4 Grading Distribution of Crushed Stone

[0081]

[0082] Example 9

[0083] A low-shrinkage, high-strength, self-compacting concrete, different from Example 1 in that:

[0084] The grading distribution of the crushed stone is as shown in Table 1-5 below.

[0085] Table 1-5 Grading Distribution of Crushed Stone

[0086]

[0087] Example 10

[0088] A low-shrinkage, high-strength, self-compacting concrete, different from Example 9 in that:

[0089] The particle size grading of the fine sand is as shown in Table 1-6 below.

[0090] Table 1-6 Particle Size Grading of Fine Sand

[0091]

[0092] Example 11

[0093] A low-shrinkage, high-strength, self-compacting concrete, different from Example 9 in that:

[0094] The particle size grading of the fine sand is as shown in Table 1-7 below.

[0095] Table 1-7 Particle Size Distribution of Fine Sand

[0096]

[0097] Example 12

[0098] A low-shrinkage, high-strength self-compacting concrete, different from Example 1 in that:

[0099] The mineral admixture is selected as phosphorus slag powder.

[0100] Example 13

[0101] A low-shrinkage, high-strength self-compacting concrete, different from Example 1 in that:

[0102] The mineral admixture is selected as fly ash and phosphorus slag powder, and the weight ratio of fly ash to phosphorus slag powder is 1:4.

[0103] Example 14

[0104] A low-shrinkage, high-strength self-compacting concrete, different from Example 1 in that:

[0105] The mineral admixture is selected as fly ash and phosphorus slag powder, and the weight ratio of fly ash to phosphorus slag powder is 9:1.

[0106] Comparative Example

[0107] Comparative Example 1

[0108] A self-compacting concrete, different from Example 1 in that:

[0109] The polyether-modified silicone oil is replaced with an equal amount of silicone oil.

[0110] Comparative Example 2

[0111] A self-compacting concrete, different from Example 1 in that:

[0112] The sodium methylene dinaphthalene sulfonate is replaced with an equal amount of polycarboxylate superplasticizer 530P.

[0113] Comparative Example 3

[0114] A self-compacting concrete, different from Example 1 in that:

[0115] The polycarboxylate superplasticizer 530P is replaced with an equal amount of sodium methylene dinaphthalene sulfonate.

[0116] Performance Detection Parameters

[0117] 1. Surface Quality: After curing in a standard curing room for 28 d, observe the surface quality of the concrete specimens, and divide the surface quality into the following three grades:

[0118] 1. The surface is uniform without large - area honeycombing;

[0119] 2. The surface is basically uniform with a small amount of small - area honeycombing in some parts;

[0120] 3. The surface is non - uniform with large - area honeycombing.

[0121] 2. Shrinkage value: Refer to Chapter 8 Shrinkage Test of GB / T 50082 - 2019 "Test Methods for Long - Term Performance and Durability of Ordinary Concrete" for detection. Among them, the size of the concrete specimen is 100mm * 100mm * 515mm. After curing for 3 days, the initial length is measured. Then, the concrete specimen is sealed with plastic wrap and transferred to a thermostatic and humidity - controlled chamber for 180 days. The length of the concrete specimen is measured again, and then the concrete shrinkage value is calculated according to the formula and recorded in Table 2 below.

[0122] 3. Compressive strength: After curing the concrete for 7 days under the same conditions, randomly select 10 concrete samples from each of the examples and comparative examples, and test the compressive strength of the concrete according to GB / T50081 - 2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete" respectively. Calculate the average compressive strength of the concrete in each example and comparative example, and calculate the standard deviation σ of the compressive strength of the concrete in each example and comparative example, and record it in Table 2 below. Among them, the smaller the standard deviation σ, the better the uniformity of the concrete, the smaller the segregation degree, and the more stable the quality of the concrete.

[0123] Table 2 Performance data of concrete

[0124]

[0125]

[0126] Result analysis

[0127] Combined with Example 1 and Comparative Examples 1 - 3 and the data in Table 2, it can be seen that polyether - modified silicone oil, methylene bis - naphthalene sulfonate, and polycarboxylate water - reducing agent can synergistically reduce the dry shrinkage of self - compacting concrete, improve the strength of self - compacting concrete, and the surface of the concrete precast parts made of self - compacting concrete has no honeycombing and pitting.

[0128] Combined with Example 1 and Examples 5 - 7 and the data in Table 2, it can be seen that when the preparation method or raw material performance parameters of polyether - modified silicone oil are different, the improvement effect of polyether - modified silicone oil on the performance of self - compacting concrete is different. Among them, it is preferred to prepare polyether - modified silicone oil by the preparation method in Examples 6 - 7 of the present application. The molecular weight of allyl alcohol polyoxyalkylene ether is preferably 1400 - 2000, the viscosity of hydrogen - containing silicone oil is preferably 20 - 25 cs, and the hydrogen content of hydrogen - containing silicone oil is preferably 1.2 - 1.4%.

[0129] Combining Example 1 with Examples 8 - 11 and with the data in Table 2 shows that the grading distribution of crushed stones and fine sand affects the dry shrinkage, strength, and uniformity of self - compacting concrete. Among them, when the grading of crushed stones and fine sand is combined in Examples 10 - 11, it is most conducive to improving various properties of self - compacting concrete.

[0130] Combining Example 1 with Examples 12 - 14 and with the data in Table 2 shows that when the mineral admixture is a mixture of fly ash and phosphorous slag powder, and the weight ratio of fly ash to phosphorous slag powder is in the range of (8 - 10):1, it can not only reduce the dry shrinkage of self - compacting concrete, improve the compactness of self - compacting concrete, but also effectively improve the quality uniformity of concrete precast members made of low - shrinkage high - strength self - compacting concrete.

[0131] This specific embodiment is only an interpretation of the present application, and it does not limit the present application. After reading this specification, those skilled in the art can make modifications without creative contributions to this specific embodiment as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A low-shrinkage, high-strength self-compacting concrete, characterized in that: it comprises the following raw materials in parts by weight: Sulfoaluminate cement: 180 - 200 parts Mineral admixture: 220 - 240 parts Crushed stone: 950 - 960 parts Fine sand: 930 - 940 parts Admixture: 8 - 12 parts Water: 130 - 140 parts The admixture includes polyether-modified silicone oil, methylene bisnaphthalene sulfonate and polycarboxylate water reducer, and the weight ratio of the polyether-modified silicone oil, methylene bisnaphthalene sulfonate and polycarboxylate water reducer is (2 - 3):(1 - 2):1; The preparation method of the polyether-modified silicone oil is as follows: After mixing 20 parts by weight of allyl alcohol polyoxyalkylene ether with 48 - 55 parts by weight of hydrogen-containing silicone oil, heating to 50 - 60 °C, and adding 1 - 2 parts by weight of a chloroplatinic acid-isopropanol solution with a weight ratio of chloroplatinic acid of 0.5 wt%, after reacting for 0.5 - 1 h, adding 80 parts by weight of allyl alcohol polyoxyalkylene ether at a rate of 1 - 2 g / min, then heating to 100 - 120 °C and continuing to react for 2 - 3 h to obtain polyether-modified silicone oil; The molecular weight of the allyl alcohol polyoxyalkylene ether is 1400 - 2000, the viscosity of the hydrogen-containing silicone oil is 20 - 25 cs, and the hydrogen content is 1.2 - 1.4%.

2. A low-shrinkage, high-strength self-compacting concrete according to claim 1, characterized in that: the weight ratio of the polyether-modified silicone oil, methylene bisnaphthalene sulfonate and polycarboxylate water reducer is 2.5:1.5:

1.

3. A low-shrinkage, high-strength self-compacting concrete according to claim 1, characterized in that: the particle size range of the crushed stone is 5 - 20 mm.

4. A low-shrinkage, high-strength self-compacting concrete according to claim 1, characterized in that: the grading distribution of the crushed stone is as follows: the residue on the 16 mm standard sieve accounts for 30% - 40 wt%, the residue on the 9.5 mm standard sieve accounts for 40% - 60 wt%, and the residue on the 4.75 mm standard sieve accounts for 10% - 20 wt%.

5. A low-shrinkage, high-strength self-compacting concrete according to claim 4, characterized in that: the particle size grading distribution of the fine sand is as follows: the residue on the 75 mm standard sieve accounts for 1 - 3 wt%, the residue on the 2.36 mm standard sieve accounts for 20 - 30 wt%, the residue on the 1.18 mm standard sieve accounts for 40 - 60 wt%, and the residue on the 0.6 mm standard sieve accounts for 19 - 27 wt%.

6. A low-shrinkage, high-strength self-compacting concrete according to claim 1, characterized in that: the mineral admixture includes fly ash and phosphorous slag powder, and the weight ratio of the fly ash and the phosphorous slag powder is (8 - 10):

1.

7. A preparation method of a low-shrinkage, high-strength self-compacting concrete according to any one of claims 1 - 6, characterized in that: it comprises the following steps: Dissolving the admixture in water to obtain an admixture solution; Adding the sulfoaluminate cement and the mineral admixture to the admixture solution and stirring evenly to obtain a cement slurry; Adding the crushed stone and the fine sand to the cement slurry and stirring evenly to obtain a low-shrinkage, high-strength self-compacting concrete.

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