Low-carbon concrete with low cement consumption and preparation method thereof

Abstract

The invention discloses low-carbon concrete with low cement consumption. The low-carbon concrete is prepared from the following components in parts by weight: 900 to 950 parts of coarse aggregate, 750 to 800 parts of fine aggregate, 500 to 550 parts of cement gel material, 5 to 10 parts of water reducing agent and 249 to 259 parts of water, the cement gel material is prepared from cement, secondary fly ash and S95 mineral powder, and the weight parts of the cement, the secondary fly ash and the S95 mineral powder are as follows: 150 to 280 parts of the cement, 70 to 130 parts of the secondary fly ash and 150 to 300 parts of the S95 mineral powder; the water-binder ratio is 0.47 to 0.49. According to the invention, mineral admixtures such as mineral powder and fly ash are used as main components, the replacement rate of the mineral admixtures to cement reaches 70%, the strength of the low-carbon concrete exceeds the C60 standard, the use amount of cement clinker is reduced, the cost is effectively reduced, the recycling of industrial wastes is promoted, and meanwhile, the cost is reduced. The principles of low-carbon environmental protection and ecological protection are implemented in the production process, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to a low-carbon concrete with low cement dosage and a preparation method thereof. Background Art

[0002] In my country's building materials industry, the production processes of manufacturing and construction industries will emit a large amount of CO2. Therefore, it is of great significance to develop new low-carbon concrete materials to reduce CO2 emissions.

[0003] Ordinary concrete cementing materials are mainly cement, mineral powder and fly ash. Generally speaking, cement accounts for more than 60%, and reducing it may damage the mechanical properties. Mineral powder accounts for a higher proportion than fly ash because it can improve early strength and crack resistance. Although fly ash is added in small amounts, it plays an important role in improving concrete workability, enhancing pumpability, reducing hydration heat and thermal expansion, and improving impermeability and durability.

[0004] In the face of environmental protection and sustainable development needs, cement-based materials are undergoing transformation, and reducing the amount of cement clinker has become a key focus. By using a large proportion of fly ash, slag and other admixtures, new low-carbon cementitious materials are developed to minimize the use of cement clinker, reduce carbon emissions, and achieve resource recycling. This strategy not only improves material performance, but also drives the cement industry towards a green and low-carbon future, showing the key direction of industry transformation. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art. The present invention provides a low-carbon concrete with low cement dosage and a preparation method thereof. By adopting mineral admixtures such as slag and fly ash as main components, the replacement rate of cement by mineral admixtures reaches 70%. The strength of the low-carbon concrete exceeds the C60 standard, the usage of cement clinker is reduced, the cost is effectively cut, and the recycling of industrial waste is promoted. At the same time, the principles of low-carbon environmental protection and ecological protection are implemented in the production process, thereby reducing production costs.

[0006] In order to achieve the above invention purpose, the technical solution provided by the present invention is as follows:

[0007] A low-carbon concrete with low cement content, comprising the following components in proportion by weight: 900-950 parts of coarse aggregate, 750-800 parts of fine aggregate, 500-550 parts of cement gel material, 5-10 parts of water reducer and 249-259 parts of water;

[0008] The cement gel material comprises cement, secondary fly ash and S95 mineral powder, wherein the weight proportions of cement, secondary fly ash and S95 mineral powder are: 150-280 parts of cement, 70-130 parts of secondary fly ash and 150-300 parts of S95 mineral powder;

[0009] The water-to-cement ratio is 0.47-0.49.

[0010] Furthermore, the fine aggregate is medium river sand with a fineness modulus of 2.5-3.0.

[0011] Furthermore, the coarse aggregate has a particle size of 5-25 mm and is continuously graded.

[0012] Furthermore, the water reducing agent is a polycarboxylic acid-based water reducing agent.

[0013] Furthermore, the cement is P052.5 cement.

[0014] A method for preparing low-carbon concrete with low cement dosage, the method specifically comprising the following steps:

[0015] S1, weigh the raw materials in proportion, measure the moisture content of coarse aggregate and fine aggregate, and calculate the water consumption after removing the moisture content of aggregate;

[0016] S2, mixing cement, mineral powder and fly ash and stirring them uniformly to obtain a cement gel material;

[0017] S3, adding coarse aggregate, fine aggregate and cement gel material into a concrete mixer in sequence for premixing;

[0018] S4, mixing the water reducing agent with the mixing water and adding the mixture into a mixer to obtain low carbon concrete.

[0019] Furthermore, the stirring speed of the mixer is 50-100 revolutions per minute, and the stirring time after adding the water reducing agent and mixing water is 5-10 minutes.

[0020] Based on the above technical solution, the low-carbon concrete with low cement dosage and its preparation method of the present invention have achieved the following technical effects through practical application:

[0021] 1. The low-carbon concrete with low cement dosage of the present invention adopts mineral admixtures such as mineral powder and fly ash as main components, and the replacement rate of cement by mineral admixtures reaches 70%. The strength of the low-carbon concrete exceeds the C60 standard, the usage of cement clinker is reduced, the cost is effectively reduced, and the recycling of industrial waste is promoted. At the same time, the principles of low-carbon environmental protection and ecological protection are implemented in the production process, thereby reducing production costs. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and effect of the present invention clearer, the present invention is described below by specific examples. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0023] A low-carbon concrete with low cement content, comprising the following components in proportion by weight: 900-950 parts of coarse aggregate, 750-800 parts of fine aggregate, 500-550 parts of cement gel material, 5-10 parts of water reducer and 249-259 parts of water;

[0024] The cement gel material comprises cement, secondary fly ash and S95 mineral powder, wherein the weight proportions of cement, secondary fly ash and S95 mineral powder are: 150-280 parts of cement, 70-130 parts of secondary fly ash and 150-300 parts of S95 mineral powder;

[0025] The water-to-cement ratio is 0.47-0.49.

[0026] The fine aggregate is medium river sand with a fineness modulus of 2.5-3.0.

[0027] The coarse aggregate has a particle size of 5-25 mm and is continuously graded.

[0028] The water reducing agent is a polycarboxylic acid water reducing agent.

[0029] The cement is P052.5 cement.

[0030] A method for preparing low-carbon concrete with low cement dosage, the method specifically comprising the following steps:

[0031] S1, weigh the raw materials in proportion, measure the moisture content of coarse aggregate and fine aggregate, and calculate the water consumption after removing the moisture content of aggregate;

[0032] S2, mixing cement, mineral powder and fly ash and stirring them uniformly to obtain a cement gel material;

[0033] S3, adding coarse aggregate, fine aggregate and cement gel material into a concrete mixer in sequence for premixing;

[0034] S4, mixing the water reducing agent with the mixing water and adding the mixture into a mixer to obtain low carbon concrete.

[0035] Furthermore, the stirring speed of the mixer is 50-100 revolutions per minute, and the stirring time after adding the water reducing agent and mixing water is 5-10 minutes.

[0036] Example 1

[0037] This embodiment discloses a low-carbon concrete with low cement dosage and a preparation method thereof, wherein the specific weight proportions are: 910 parts of coarse aggregate, 788 parts of fine aggregate, 530 parts of cement gel material, 5.5 parts of water reducer and 259 parts of water.

[0038] In this embodiment, the weight proportions of cement gel materials are as follows: 280 parts of cement, 180 parts of mineral powder, and 70 parts of fly ash.

[0039] In this embodiment, the water reducer is a high-performance polycarboxylate water reducer.

[0040] In this embodiment, the preparation method of the cement gel material is:

[0041] Step 1, weigh the raw materials in proportion, measure the moisture content of coarse aggregate and fine aggregate, and calculate the water consumption after removing the moisture content of aggregate;

[0042] Step 2, mixing cement, mineral powder and fly ash, stirring evenly to obtain a mixed material;

[0043] Step 3, adding coarse aggregate, fine aggregate and cement gel material into a concrete mixer in sequence for premixing;

[0044] Step 4: Mix the water reducer with the mixing water and add them into a mixer and stir at a speed of 50-100 revolutions per minute for 5-10 minutes.

[0045] The low-carbon concrete of this embodiment has a controlled cost due to the reduced cement dosage. The proportion of mineral powder in concrete is increased, and its main function is to provide early strength of concrete and significantly improve its crack resistance and durability. In contrast, the amount of fly ash added is relatively small, because excessive fly ash may affect the early strength of concrete. Therefore, in the current concrete formula, fly ash mainly plays a filling and lubricating role, optimizes the workability of concrete, and enhances pumpability. The two work together on concrete, each showing its strengths.

[0046] Example 2

[0047] This embodiment discloses a low-carbon concrete with low cement dosage, which comprises the following parts by weight: 910 parts of coarse aggregate, 788 parts of fine aggregate, 530 parts of cement gel material, 7.2 parts of water reducer and 254 parts of water.

[0048] In this embodiment, the weight proportions of cement gel materials are as follows: 265 parts of cement, 156 parts of mineral powder, and 106 parts of fly ash.

[0049] Embodiment 3:

[0050] This embodiment discloses a low-carbon concrete with low cement dosage, which comprises the following parts by weight: 910 parts of coarse aggregate, 788 parts of fine aggregate, 530 parts of cement gel material, 9.1 parts of water reducer and 249 parts of water.

[0051] In this embodiment, the weight proportions of cement gel materials are as follows: 212 parts of cement, 191 parts of mineral powder, and 127 parts of fly ash.

[0052] Embodiment 4:

[0053] This embodiment discloses a low-carbon concrete with low cement dosage, which comprises the following parts by weight: 910 parts of coarse aggregate, 788 parts of fine aggregate, 530 parts of cement gel material, 7.4 parts of water reducer and 254 parts of water.

[0054] In this embodiment, the weight proportions of cement gel materials are as follows: 159 parts of cement, 296 parts of mineral powder, and 74 parts of fly ash.

[0055] The cementitious material ratios of the low-carbon concrete of the above four embodiments are shown in Table 1, and the performance of the low-carbon concrete was tested, and the test results are shown in Table 2.

[0056]

[0057] Table 1

[0058]

[0059]

[0060] Table 2

[0061] Comparative Example 1

[0062] A common concrete comprises the following parts by weight: 910 parts of coarse aggregate, 788 parts of fine aggregate, 530 parts of cement gel material, 7 parts of water reducing agent and 250 parts of water.

[0063] In this comparative example, the weight proportions of cement gel materials are as follows: 370 parts of cement, 80 parts of mineral powder, and 80 parts of fly ash. The preparation method is the same as that of Example 1.

[0064] Comparative Example 2

[0065] A common concrete comprises the following parts by weight: 910 parts of coarse aggregate, 788 parts of fine aggregate, 530 parts of cement gel material, 7 parts of water reducing agent and 250 parts of water.

[0066] In this comparative example, the weight proportions of cement gel materials are as follows: 318 parts of cement, 159 parts of mineral powder, and 53 parts of fly ash. The preparation method is the same as that of Example 1.

[0067] The cementitious material ratios of the ordinary concrete of the above two comparative examples are shown in Table 3, and the performance test comparisons with the low-carbon concrete of the four embodiments are shown in Table 4.

[0068]

[0069] Table 3

[0070]

[0071] Table 4

[0072] According to the test results of the above embodiments and comparative examples, the 28d compressive strength of the four low-carbon concretes in Examples 1 to 4 all reached the C60 standard, which is significantly higher than that of ordinary concrete. These low-carbon concretes significantly reduce the use of commercial cement, and the replacement rate of cement by mineral admixtures can reach up to 70%, effectively reducing production costs, reducing carbon emissions, and showing good environmental benefits.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the 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 solution of the present invention, which should all be covered by the scope of the technical solution for protection of the present invention.

Claims

1. A low-carbon concrete with low cement content, characterized in that: The invention comprises the following components in proportion by weight: 900-950 parts of coarse aggregate, 750-800 parts of fine aggregate, 500-550 parts of cement gel material, 5-10 parts of water reducing agent and 249-259 parts of water; The cement gel material comprises cement, secondary fly ash and S95 mineral powder, wherein the weight proportions of cement, secondary fly ash and S95 mineral powder are: 150-280 parts of cement, 70-130 parts of secondary fly ash and 150-300 parts of S95 mineral powder; The water-to-cement ratio is 0.47-0.

49.

2. The low-carbon concrete with low cement content according to claim 1, characterized in that: The fine aggregate is medium river sand with a fineness modulus of 2.5-3.

0.

3. The low-carbon concrete with low cement content according to claim 1, characterized in that: The coarse aggregate has a particle size of 5-25 mm and is continuously graded.

4. The low-carbon concrete with low cement content according to claim 1, characterized in that: The water reducing agent is a polycarboxylic acid water reducing agent.

5. The low-carbon concrete with low cement content according to claim 1, characterized in that: The cement is P052.5 cement.

6. A method for preparing low-carbon concrete with low cement content, characterized in that: The method specifically comprises the following steps: S1, weigh the raw materials in proportion, measure the moisture content of coarse aggregate and fine aggregate, and calculate the water consumption after removing the moisture content of aggregate; S2, mixing cement, mineral powder and fly ash and stirring them uniformly to obtain a cement gel material; S3, adding coarse aggregate, fine aggregate and cement gel material into a concrete mixer in sequence for premixing; S4, mixing the water reducing agent with the mixing water and adding the mixture into a mixer to obtain low carbon concrete.

7. The method for preparing low-carbon concrete with low cement content according to claim 6, characterized in that: The stirring speed of the mixer is 50-100 revolutions per minute, and the stirring time after adding the water reducing agent and mixing water is 5-10 minutes.

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