A preparation method of low-heat micro-expansion concrete

Abstract

The present invention relates to a method for preparing low-heat, micro-expansion concrete. The method mainly uses slag as a raw material, adds an appropriate amount of silicate cement clinker and dehydrated gypsum to grind the concrete, and directly produces the low-heat, micro-expansion cement using cement clinker, slag and dehydrated gypsum. The production process is simplified, energy consumption and production costs are reduced, energy saving and waste utilization effects are significant, and the performance is excellent. The low-heat, micro-expansion concrete prepared by the present invention has micro-expansion properties during autogenous volume deformation, has a good deformation morphology, a large expansion amount, is stable and does not shrink in the later stage, and has excellent technical performance indicators. It greatly simplifies various temperature control measures in dam construction, accelerates construction progress, effectively prevents shrinkage cracks in concrete, and produces good economic and quality effects.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and in particular relates to a method for preparing low-heat micro-expansion concrete. Background Art

[0002] Low-heat, slightly expansive cement is a hydraulic cementitious material made from granulated blast furnace slag as the main component, with an appropriate amount of Portland cement clinker and gypsum ground into it. It has the characteristics of low hydration heat and slight volume expansion, rapid early strength development, and high flexural strength. It can be used in dam projects and large-volume concrete projects.

[0003] Chinese Patent CN201110383109.4 discloses a method for producing low-heat, slightly expansive cement, comprising the following steps: 1) mixing, by weight, vanadium-titanium slag: 2-30 parts; phosphorus slag: 2-30 parts; granulated blast furnace slag: 20-62 parts; cement clinker: 18-45 parts; gypsum or anhydrite: 7-15 parts; and other admixtures: 0.2-5 parts; 2) grinding the slag to a fineness of 0.08 mm and a sieve residue of less than 5%; 3) feeding the ore powder into a discharge elevator, and adding the clinker, gypsum or anhydrite, and other admixtures prepared in step 1) to the mill inlet; 4) adjusting the specific surface area of ​​the ground product and the ratio of all components in step 1) to produce the finished low-heat, slightly expansive cement. The present invention is simple in process and, in resource-limited situations, can reduce production costs by using vanadium-titanium slag, phosphorus slag, and other ingredients to partially replace the existing low-heat, slightly expansive cement formula.

[0004] Chinese patent CN201110383108.X discloses a low-heat, micro-expansion cement, relating to the field of engineering materials technology. The cement is prepared by mixing the following components, by weight: 2-30 parts vanadium-titanium slag; 2-30 parts phosphorus slag; 20-62 parts granulated blast furnace slag; 18-45 parts cement clinker; 7-15 parts gypsum or anhydrite; and 0.2-5 parts other admixtures. This invention allows for the comprehensive utilization of vanadium-titanium slag resources. In situations where resources are scarce, vanadium-titanium slag, phosphorus slag, and other additives can be used to partially replace existing low-heat, micro-expansion cement formulations. This reduces production costs, and the physical properties of the cement produced meet the requirements of the GB2938 cement standard.

[0005] Chinese patent CN201811205816.2, pertaining to the concrete field, discloses a low-heat, low-expansion cement-based radiation-proof concrete and its preparation method. The concrete is composed of the following materials, measured by weight: 280-320 parts cement, 900-1200 parts fine aggregate, 1200-1500 parts coarse aggregate, 10-20 parts neutron absorber, 0.4-0.6 parts water reducer, and 140-160 parts water. The concrete meets the strength requirements of C30 concrete, exhibits no segregation, exhibits good slump and expansion, has a bulk density between 2800-2900 kg·m³, and exhibits a 28-day limited expansion rate of 0.004-0.007% under water-cured conditions.

[0006] The low-heat, slightly expansive concrete prepared by the above patents and prior art has a large unit power consumption, a large amount of slag, a high cement hydration heat, and poor overall cement performance. Summary of the Invention

[0007] The present invention aims to overcome the shortcomings of the prior art and provide a method for preparing low-heat, micro-expansion concrete. The method mainly uses slag as raw material, adds appropriate amounts of silicate cement clinker and dehydrated gypsum to grind the concrete, and directly produces low-heat, micro-expansion cement using cement clinker, slag and dehydrated gypsum.

[0008] In one aspect of the present invention, the present invention provides a method for preparing low-heat, low-expansion concrete, wherein the steps are as follows, in parts by weight:

[0009] S1: Weigh 35-45 parts of clinker, 40-45 parts of slag, 8-12 parts of dehydrated gypsum, 0.2-1 parts of admixture, and 0.002-0.03 parts of retarder by weight and place them in an oven for drying;

[0010] S2: After cooling, it is sent to the mill elevator and ground in the closed-flow mill system;

[0011] S3: After grinding, use a standard sieve to remove coarse particles to obtain low-heat, slightly expanding concrete.

[0012] Preferably, in S1, the clinker is Portland cement clinker.

[0013] Preferably, in S1, the slag is granulated blast furnace slag.

[0014] Preferably, in S1, the external admixture is fly ash or light-burned MgO.

[0015] Preferably, in S1, the oven temperature is controlled at 90-105° C. for 18-24 hours.

[0016] Preferably, in S3, the aperture of the standard sieve is 0.88 mm.

[0017] Preferably, in S3, the specific surface area of ​​the low-heat micro-expansion cement product is controlled to be 450-550m 2 / kg.

[0018] Preferably, in S3, the retarder is a compound of two components: ethylene glycol diethyl ether diamine tetraacetic acid and pentaerythritol-based heterometallic retarder, and the mass ratio of the two is 10-20:0.3-3.5.

[0019] In another aspect of the present invention, a method for preparing a pentaerythritol-based heterometallic retarder is provided:

[0020] S1: Add 100-130 parts of pentaerythritol tetrakis(3-mercaptopropionate) and 500-700 parts of toluene, 0.01-0.3 parts of vinylferrocene, 3-7 parts of copper 9-octadecenoate, 6-12 parts of allylzinc bromide, and 2-4 parts of an organic base, heating and stirring to 70-82°C, and reacting for 30-100 minutes;

[0021] S2: Add 0.02-0.6 parts of azobisisobutyronitrile, react at 70-82°C for 10-30 minutes, and distill off toluene to obtain a pentaerythritol-based heterometallic retarder.

[0022] Furthermore, the organic base is selected from triethylamine or diethylamine.

[0023] Reaction mechanism:

[0024] The reaction mechanism of the pentaerythritol-based heterometallic retarder is as follows: the pentaerythritol tetrakis (3-mercaptopropionate) reacts with vinylferrocene, copper 9-octadecenoate and allylzinc bromide to form a stable heterometallic pentaerythritol derivative, thereby obtaining the pentaerythritol-based heterometallic retarder.

[0025] Technical effect:

[0026] Compared with the prior art, the method for preparing low-heat micro-expansion concrete of the present invention has the following significant effects:

[0027] 1. The pentaerythritol-based heterometallic retarder prepared by the present invention has good stability, is not easily oxidized, and can be stably present in concrete; pentaerythritol ferrocene may achieve a retarding effect by slowing down the chemical reaction rate in concrete; pentaerythritol copper may achieve a retarding effect by inhibiting the movement of particles in concrete and reducing the hydration reaction rate; zinc bromide has good water solubility and chemical stability, and can achieve a retarding effect by reducing the ion exchange rate in concrete.

[0028] 2. The low-heat, low-expansion concrete prepared by the present invention is mainly made from slag as raw material, with appropriate amounts of Portland cement clinker and dehydrated gypsum added and ground into it. The low-heat, low-expansion cement is directly produced from cement clinker, slag and dehydrated gypsum, which simplifies the production process, reduces energy consumption and production costs, and has significant energy-saving and waste-recycling effects. It has excellent performance and provides a high-quality and suitable material for the construction of large-volume concrete, crack resistance and anti-seepage projects.

[0029] 3. The low-heat micro-expansion concrete prepared by the present invention has micro-expansion performance in its autogenous volume deformation, good deformation morphology, large expansion amount, stability and no shrinkage in the later stage, and excellent technical performance indicators. It greatly simplifies various temperature control measures in dam construction, speeds up the construction progress, effectively prevents shrinkage cracks in concrete, and produces good economic and quality effects. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to the examples. The following examples are merely illustrative and non-limiting, and the scope of protection of the present invention cannot be limited thereto.

[0031] Example 1

[0032] A method for preparing low-heat, slightly expansive concrete, comprising the following steps:

[0033] S1: Weigh 35kg clinker, 40kg slag, 8kg dehydrated gypsum, 0.2kg admixture, and 0.002kg retarder and put them into an oven for drying;

[0034] S2: After cooling, it is sent to the mill elevator and ground in the closed-flow mill system;

[0035] S3: After grinding, use a standard sieve to remove coarse particles to obtain low-heat, slightly expanding concrete.

[0036] The clinker is Portland cement clinker.

[0037] The slag is granulated blast furnace slag.

[0038] The external admixture is fly ash.

[0039] The oven temperature is controlled at 90° C. for 18 hours.

[0040] The aperture of the standard sieve is 0.88 mm.

[0041] The specific surface area of ​​the low-heat micro-expansion cement product is controlled at 450m 2 / kg.

[0042] The retarder is compounded from two components: ethylene glycol diethyl ether diamine tetraacetic acid and pentaerythritol-based heterometallic retarder, with the mass ratio of the two being 10:0.3.

[0043] The preparation method of the pentaerythritol-based heterometallic retarder is as follows:

[0044] S1: Add 100 kg of pentaerythritol tetrakis(3-mercaptopropionate) and 500 kg of toluene, 0.01 kg of vinylferrocene, 3 kg of copper 9-octadecenoate, 6 kg of allylzinc bromide, and 2 kg of an organic base, heat and stir to 70°C, and react for 30 minutes;

[0045] S2: Add 0.02 kg of azobisisobutyronitrile, react at 70° C. for 10 minutes, and distill off toluene to obtain a pentaerythritol-based heterometallic retarder.

[0046] The organic base is selected from triethylamine.

[0047] Example 2

[0048] A method for preparing low-heat, slightly expansive concrete, comprising the following steps:

[0049] S1: Weigh 38 kg of clinker, 42 kg of slag, 9 kg of dehydrated gypsum, 0.5 kg of admixture, and 0.013 kg of retarder and put them into an oven for drying;

[0050] S2: After cooling, it is sent to the mill elevator and ground in the closed-flow mill system;

[0051] S3: After grinding, use a standard sieve to remove coarse particles to obtain low-heat, slightly expanding concrete.

[0052] The clinker is Portland cement clinker.

[0053] The slag is granulated blast furnace slag.

[0054] The external admixture is fly ash.

[0055] The oven temperature is controlled at 95° C. for 20 hours.

[0056] The aperture of the standard sieve is 0.88 mm.

[0057] The specific surface area of ​​the low-heat micro-expansion cement product is controlled at 480m 2 / kg.

[0058] The retarder is compounded from two components: ethylene glycol diethyl ether diamine tetraacetic acid and pentaerythritol-based heterometallic retarder, with the mass ratio of the two being 14:1.5.

[0059] The preparation method of the pentaerythritol-based heterometallic retarder is as follows:

[0060] S1: Add 110 kg of pentaerythritol tetrakis(3-mercaptopropionate) and 550 kg of toluene, 0.1 kg of vinylferrocene, 4 kg of copper 9-octadecenoate, 8 kg of allylzinc bromide, and 3 kg of an organic base, heat and stir to 75°C, and react for 60 minutes;

[0061] S2: Add 0.2 kg of azobisisobutyronitrile, react at 75° C. for 15 minutes, and distill off toluene to obtain a pentaerythritol-based heterometallic retarder.

[0062] The organic base is selected from triethylamine.

[0063] Example 3

[0064] A method for preparing low-heat, slightly expansive concrete, comprising the following steps:

[0065] S1: Weigh 42 kg of clinker, 44 kg of slag, 11 kg of dehydrated gypsum, 0.8 kg of admixture, and 0.02 kg of retarder and put them into an oven for drying;

[0066] S2: After cooling, it is sent to the mill elevator and ground in the closed-flow mill system;

[0067] S3: After grinding, use a standard sieve to remove coarse particles to obtain low-heat, slightly expanding concrete.

[0068] The clinker is Portland cement clinker.

[0069] The slag is granulated blast furnace slag.

[0070] The external addition is light-burned MgO.

[0071] The oven temperature is controlled at 100° C. for 22 hours.

[0072] The aperture of the standard sieve is 0.88 mm.

[0073] The specific surface area of ​​the low-heat micro-expansion cement product is controlled at 530m 2 / kg.

[0074] The retarder is compounded from two components: ethylene glycol diethyl ether diamine tetraacetic acid and pentaerythritol-based heterometallic retarder, with the mass ratio of the two being 18:2.5.

[0075] The preparation method of the pentaerythritol-based heterometallic retarder is as follows:

[0076] S1: Add 120 kg of pentaerythritol tetrakis(3-mercaptopropionate) and 650 kg of toluene, 0.2 kg of vinylferrocene, 6 kg of copper 9-octadecenoate, 11 kg of allylzinc bromide, and 3 kg of an organic base, heat and stir to 80°C, and react for 90 minutes;

[0077] S2: 0.4 kg of azobisisobutyronitrile was added, and the mixture was reacted at 80° C. for 25 minutes. Toluene was distilled off to obtain a pentaerythritol-based heterometallic retarder.

[0078] The organic base is selected from diethylamine.

[0079] Example 4

[0080] A method for preparing low-heat, slightly expansive concrete, comprising the following steps:

[0081] S1: Weigh 45 kg of clinker, 45 kg of slag, 12 kg of dehydrated gypsum, 1 kg of admixture, and 0.03 kg of retarder and put them into an oven for drying;

[0082] S2: After cooling, it is sent to the mill elevator and ground in the closed-flow mill system;

[0083] S3: After grinding, use a standard sieve to remove coarse particles to obtain low-heat, slightly expanding concrete.

[0084] The clinker is Portland cement clinker.

[0085] The slag is granulated blast furnace slag.

[0086] The external addition is light-burned MgO.

[0087] The oven temperature is controlled at 105° C. for 24 hours.

[0088] The aperture of the standard sieve is 0.88 mm.

[0089] The specific surface area of ​​the low-heat micro-expansion cement product is controlled at 550m 2 / kg.

[0090] The retarder is compounded from two components: ethylene glycol diethyl ether diamine tetraacetic acid and pentaerythritol-based heterometallic retarder, with the mass ratio of the two being 20:3.5.

[0091] The preparation method of the pentaerythritol-based heterometallic retarder is as follows:

[0092] S1: Add 130 kg of pentaerythritol tetrakis(3-mercaptopropionate) and 700 kg of toluene, 0.3 kg of vinylferrocene, 7 kg of copper 9-octadecenoate, 12 kg of allylzinc bromide, and 4 kg of an organic base, heat and stir to 82°C, and react for 100 minutes;

[0093] S2: Add 0.6 kg of azobisisobutyronitrile, react at 82° C. for 30 minutes, and distill off toluene to obtain a pentaerythritol-based heterometallic retarder.

[0094] The organic base is selected from diethylamine.

[0095] Comparative Example 1

[0096] The pentaerythritol-based heterometallic retarder was not added, and the other procedures were the same as in Example 1.

[0097] Comparative Example 2

[0098] Without adding vinylferrocene, the other steps were the same as in Example 1.

[0099] Comparative Example 3

[0100] The other steps were the same as in Example 1 except that copper 9-octadecenoate was not added.

[0101] Comparative Example 4

[0102] Allyl zinc bromide was not added, and the other procedures were the same as in Example 1.

[0103] The test methods of the embodiment and the comparison machine in this method refer to GB2938-2008, and the test results are shown in the following table:

[0104]

[0105] Through the analysis of the above examples and comparative examples, the pentaerythritol-based heterometallic retarder prepared by the present invention has a good retarding effect; the low-heat micro-expansion concrete prepared by the present invention has a low expansion rate and hydration heat, providing a high-quality and suitable material for the construction of large-volume concrete, crack resistance, and anti-seepage projects.

[0106] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as not within the scope of protection of the invention.

Claims

1. A method for preparing low-heat, slightly expansive concrete, wherein the steps are as follows, in parts by weight: S1: Weigh 35-45 parts of clinker, 40-45 parts of slag, 8-12 parts of dehydrated gypsum, 0.2-1 parts of admixture, and 0.002-0.03 parts of retarder by weight and place them in an oven for drying; S2: After cooling, it is sent to the mill elevator and ground in the closed-flow mill system; S3: After grinding, coarse particles are removed using a standard sieve to obtain low-heat, slightly expanding concrete; The retarder is a compound of two components: ethylene glycol diethyl ether diamine tetraacetic acid and pentaerythritol-based heterometallic retarder, with a mass ratio of 10-20:0.3-3.5; The preparation method of the pentaerythritol-based heterometallic retarder is as follows: S1: Add 100-130 parts of pentaerythritol tetrakis(3-mercaptopropionate) and 500-700 parts of toluene, 0.01-0.3 parts of vinylferrocene, 3-7 parts of copper 9-octadecenoate, 6-12 parts of allylzinc bromide, and 2-4 parts of an organic base, heating and stirring to 70-82°C, and reacting for 30-100 minutes; S2: Add 0.02-0.6 parts of azobisisobutyronitrile, react at 70-82°C for 10-30 minutes, and distill off toluene to obtain a pentaerythritol-based heterometallic retarder.

2. The method for preparing low-heat, slight expansion concrete according to claim 1, wherein: The clinker is Portland cement clinker.

3. The method for preparing low-heat, slight expansion concrete according to claim 1, wherein: The slag is granulated blast furnace slag.

4. The method for preparing low-heat, slight expansion concrete according to claim 1, wherein: The external admixture is fly ash or light-burned MgO.

5. The method for preparing low-heat, slight expansion concrete according to claim 1, wherein: The oven temperature is controlled at 90-105° C. for 18-24 hours.

6. The method for preparing low-heat, slight expansion concrete according to claim 1, wherein: The aperture of the standard sieve is 0.88 mm.

7. The method for preparing low-heat, slight expansion concrete according to claim 1, wherein: The organic base is selected from triethylamine or diethylamine.

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