A weighting agent for preparing concrete, a weighted concrete and a method of preparing and use thereof

Abstract

The application relates to the technical field of concrete, and specifically discloses a weight agent for preparing concrete, weight concrete and a preparation method and application thereof. The weight agent for preparing concrete comprises the following components in parts by weight: calcium-based carbonized sawdust 20-30 parts, HSH polyether polyol 5-12 parts, iron ore sand 76-84 parts and nano iron powder 12-19 parts; wherein, the preparation method of the calcium-based carbonized sawdust is as follows: calcium carbonate and sawdust raw materials are mixed according to a weight ratio of (8-14):100, then anaerobic carbonization and pulverization are carried out to obtain the calcium-based carbonized sawdust. The application further discloses weight concrete prepared by using the weight agent. The weight agent disclosed by the application is used for preparing weight concrete, the weight of the weight concrete can be improved, and the concrete has good compressive strength and crack resistance.

Description

Technical Field

[0001] The present application relates to the technical field of concrete, and in particular to a weighting agent for preparing concrete, weighted concrete, and a preparation method and application thereof. Background Art

[0002] Ballasted concrete is now widely used in construction machinery, lifting machinery, ships, transportation, water conservancy and hydropower projects, and other projects requiring ballast and counterweight. Currently, the primary method for producing ballasted concrete is to use high-density materials such as iron ore or iron ore sand to partially or completely replace the aggregate in conventional commercial concrete, thereby increasing the concrete's density.

[0003] However, in today's resource-scarce economic structure, energy is becoming increasingly scarce and prices are soaring. Using expensive refined iron ore as concrete aggregate will greatly increase the production cost of counterweight concrete and reduce the economic benefits of the enterprise.

[0004] In addition, a technical difficulty in the field of counterweight concrete in the prior art is how to improve the bulk density performance of concrete while ensuring the strength of concrete.

[0005] Therefore, it is necessary to develop a new counterweight concrete. Summary of the Invention

[0006] In order to increase the bulk density of concrete while ensuring the strength of concrete, the present application provides a weighting agent for preparing concrete, weighted concrete, and a preparation method and application thereof.

[0007] In a first aspect, the present application provides a weighting agent for preparing concrete, characterized in that it specifically comprises the following components in parts by weight: 20-30 parts of calcium-based carbonized sawdust, 5-12 parts of HSH polyether polyol, 76-84 parts of iron ore, and 12-19 parts of nano iron powder;

[0008] The preparation method of the calcium-based carbonized sawdust is as follows: calcium carbonate and sawdust raw materials are mixed in a weight ratio of (8-14):100, and then anaerobic carbonization and crushing are performed to obtain the mixture.

[0009] This application utilizes calcium carbonate and sawdust as raw materials, which are carbonized and then combined with HSH polyether polyol, iron ore, and nano-iron powder to produce a counterweight. This counterweight is used to prepare weighted concrete, increasing the concrete's bulk density while maintaining its strength and imparting excellent crack resistance. The technical solution provided by this application also significantly reduces the amount of iron ore used, lowering the production cost of preparing weighted concrete.

[0010] Compared with ordinary untreated sawdust raw materials, this application uses a mixture of calcium carbonate and sawdust. During the carbonization process, the calcium carbonate decomposes to produce fine calcium oxide, which then diffuses and fills the narrow pores in the carbonized sawdust product, reducing the specific surface energy of the sawdust carbonization product's own structure, reducing the phenomenon of the sawdust carbonization product's own cohesion and agglomeration, and thus improving the dispersibility of the sawdust carbonization product in the counterweight concrete system.

[0011] The inventors of the present application have discovered that HSH polyether polyol can be used as a viscosity regulator for a weighting agent. After being mixed with calcium-based carbonized sawdust and iron ore, the calcium-based carbonized sawdust has a strong surface bonding force with the iron ore and nano-iron powder. At the same time, the calcium-based carbonized sawdust can be fully filled in the central voids of the iron ore, and the concrete is transformed from a skeleton void structure to a dense structure, which effectively improves the internal density of the weighted concrete, thereby improving the bulk density performance of the concrete; at the same time, the compressive strength of the concrete is improved, and the later mechanical properties of the weighted concrete product are effectively guaranteed.

[0012] The weighting agent prepared in this application can have good compatibility with cement, water reducing agent and other auxiliary materials, adjust the viscosity and system stability of the weighted concrete, make the water inside the weighted concrete slurry evenly distributed, and have a stronger ability to lock water, less likely to lose water, better moisturizing effect, better reduce shrinkage, improve the curing effect, and enable the weighted concrete to use its own water to complete the hydration effect to the maximum extent, making the concrete less likely to crack. In addition, the weighting agent can not only provide a larger steric hindrance for the weighted concrete and improve the dispersion performance of each component, but also effectively avoid the agglomeration of long side chain substances in the concrete, thereby allowing the cement to maintain good fluidity, so that the weighted concrete will not migrate or precipitate over time and affect the crack resistance of the concrete, which helps to make the concrete obtain lasting aging resistance and extend its service life.

[0013] Preferably, the weighting agent for preparing concrete comprises the following components in parts by weight: 24-28 parts of calcium-based carbonized sawdust, 7-10 parts of HSH polyether polyol, 78-82 parts of iron ore, and 13-17 parts of nano iron powder.

[0014] Furthermore, the weighting agent for preparing concrete includes the following components in parts by weight: 26 parts of calcium-based carbonized sawdust, 8 parts of HSH polyether polyol, 80 parts of iron ore, and 15 parts of nano iron powder.

[0015] Through experimental analysis, it can be seen that this application controls the amount of each raw material in the weighting agent to the above range, and uses the prepared weighting agent to prepare concrete, which can further improve the bulk density performance of concrete while ensuring that the mechanical properties of concrete are not reduced.

[0016] In the process of exploring the preparation method of calcium-based carbonized sawdust, the inventors found that the carbonization parameters and the particle size of the crushed sawdust have a great influence on the role of the calcium-based carbonized sawdust in the counterweight agent. Therefore, it is necessary to reasonably control the specific parameters in the preparation process of calcium-based carbonized sawdust.

[0017] Preferably, the anaerobic carbonization step is specifically as follows: under anaerobic conditions, heating the raw material from room temperature to 850-900°C at a heating rate of 5-10°C / min, carbonizing for 2-3 hours, and then cooling to room temperature at a rate of 10-20°C / min to obtain a carbonized product.

[0018] In a specific embodiment, the heating rate can be 5°C / min, 8°C / min, or 10°C / min.

[0019] In a specific embodiment, the cooling rate can be 10°C / min, 15°C / min, or 20°C / min.

[0020] Preferably, the pulverizing step is specifically as follows: the carbonized product is pulverized to 2 μm-10 μm by ball milling at a rotation speed of 200-250 r / min and a ball-to-material ratio of (1-2):1.

[0021] In a specific embodiment, the particle size of the calcium-based carbonized wood chips may be 2 μm, 6 μm, or 10 μm.

[0022] In some specific embodiments, the particle size of the calcium-based carbonized wood chips may also be 2-6 μm or 6-10 μm.

[0023] Through experimental analysis, it can be seen that the present application selects calcium-based carbonized wood chips of the above-mentioned particle size as the raw material component of the weighting agent, which can further improve the performance of concrete.

[0024] Preferably, the HSH polyether polyol has a hydroxyl value of 60-200 mgKOH / g and an acid value of ≤0.15 mgKOH / g.

[0025] Furthermore, the HSH polyether polyol has a hydroxyl value of 90-140 mgKOH / g and an acid value of ≤0.15 mgKOH / g.

[0026] Through experimental analysis, it can be seen that the application selects HSH polyether polyol with the above-mentioned specifications as the raw material component of the weighting agent, which can further improve the performance of concrete.

[0027] Preferably, the apparent density of the iron ore is: 4.2-5.2 g / cm 3 , particle size is 0.01-2 mm.

[0028] Preferably, the particle size of the nano iron powder is 800±100 nm.

[0029] Preferably, the weighting agent used to prepare concrete is a powder, and the particle size of the weighting agent is 0.01-2 mm.

[0030] In a second aspect, the present application provides the use of the above-mentioned weighting agent in preparing concrete.

[0031] In a third aspect, the present application provides a counterweight concrete, including the above-mentioned counterweight agent, specifically including the following components in parts by weight: 100-120 parts of cement, 46-52 parts of counterweight agent, 0.06-0.12 parts of water reducer, 0.01-0.08 parts of defoaming agent, 0.02-0.12 parts of thickener, and 40-60 parts of water.

[0032] Preferably, the water reducer is a polycarboxylate water reducer.

[0033] In a fourth aspect, the present application provides a method for preparing the above-mentioned counterweight concrete, which specifically comprises the following steps:

[0034] Mixing the cement and the weighting agent uniformly to obtain dry material;

[0035] uniformly dispersing the water reducing agent, the defoaming agent, and the thickener in the water to obtain a mixed solution;

[0036] The mixed solution is added to the dry material and stirred for 30-60 seconds to obtain the counterweight concrete.

[0037] In a fourth aspect, the present application provides the application of the above-mentioned counterweight concrete in bridge box girder counterweight components or building anti-floating counterweight components.

[0038] The counterweight concrete provided in this application can be used for bridge box girder counterweight components, such as large and medium-sized highway and railway bridges, and can fully meet the use of cast-in-place beams, prefabricated beams and steel box beams; it can also be used for building anti-floating counterweight components, such as underground garages, sunken squares, underground stations, and main-podium-style commercial complex underground structure foundation anti-floating counterweights.

[0039] In summary, the technical solution of this application has the following effects:

[0040] The present application utilizes calcium carbonate and sawdust carbonized calcium-based carbonized sawdust in combination with HSH polyether polyol, iron ore, and nano-iron powder to obtain a counterweight agent, which is used to prepare counterweight concrete, which can significantly increase the bulk density of the concrete, and the concrete has good compressive strength and crack resistance.

[0041] The application optimizes the preparation method of calcium-based carbonized sawdust and the type of HSH polyether polyol, so that the prepared weighting agent has better compatibility with cement, water reducing agent and other auxiliary materials, further enhances the performance of the weighting concrete, helps the concrete to obtain durable aging resistance and prolong the service life.

[0042] The concrete provided by the application is pumpable and hoistable, and has strong adaptability to site, stable quality and good durability. DETAILED DESCRIPTION

[0043] The application will be further described in detail below in combination with examples, comparative examples and performance test experiments, and these examples cannot be understood as limiting the scope of the application claimed.

[0044] The sawdust raw material used in the test of the application was purchased from Shijiazhuang Tesen Mining Co., Ltd., the iron ore sand was purchased from Lingshou County Qiangdong Mineral Product Processing Factory, the nano iron powder (model DK-Fe-002, 800±100nm) was purchased from Beijing Dekedao Gold Technology Co., Ltd., the HSH polyether polyol was purchased from Haian Petrochemical Factory in Jiangsu Province, the P.O 22.5 ordinary portland cement was purchased from Lingshou County Yuan Tong Mineral Product Trade Co., Ltd., the polycarboxylic acid water reducing agent (model TD-JSS) was purchased from Tada (Shandong) New Material Technology Industry Group Co., Ltd.; the defoaming agent (model XWC-0285 powder / T112) was purchased from Hefei Xinniancheng Environmental Protection Technology Co., Ltd., the thickening agent (model Rheovis PU 1190) was purchased from Chongqing Pingchuan Chemical Co., Ltd.; the rest of the raw materials can be obtained by commercial purchase.

[0045] Preparation example.

[0046] Preparation examples 1-5.

[0047] Preparation examples 1-5 respectively provide a weighting agent for preparing concrete.

[0048] The difference between the above preparation examples is that the weight ratio of calcium carbonate to sawdust raw material in the preparation method of calcium-based carbonized sawdust is different, and the specific weight ratio is shown in Table 1.

[0049] The preparation method of calcium-based carbonized sawdust in the present preparation example is as follows:

[0050] After the calcium carbonate and the sawdust raw material are uniformly mixed according to the weight ratio shown in Table 1, they are placed in a high-temperature furnace, and the temperature is raised from room temperature to 850±10℃ at a heating rate of 8±2℃ / min, and then the temperature is lowered to room temperature at a cooling rate of 15±2℃ / min after carbonization for 2h, to obtain a carbonized product;

[0051] The carbonized product is ball milled to 6±0.5μm under the conditions of a rotation speed of 230r / min and a ball-to-material ratio of 1:5:1, to obtain the calcium-based carbonized sawdust.

[0052] The preparation method of the weighting agent in the present preparation example is as follows:

[0053] The calcium-based carbonized sawdust 25 g, HSH polyether polyol (model specification HSH-210, hydroxyl value 105-119 mgKOH / g, acid value ≤0.15 mgKOH / g) 8 g, iron ore 80 g, and nano-iron powder 15 g were weighed and uniformly mixed to obtain the weighting agent.

[0054] Table 1 Weight ratio of calcium carbonate and sawdust raw materials in preparation examples 1-5

[0055] .

[0056] Preparation examples 6-9.

[0057] Preparation examples 6-9 respectively provide a weighting agent for preparing concrete.

[0058] The difference between the above preparation example and preparation example 3 is that the process parameters are different in the preparation method of the calcium-based carbonized sawdust, which is shown as follows.

[0059] In preparation example 6, the heating rate is 2±2℃ / min.

[0060] In preparation example 7, the heating rate is 13±2℃ / min.

[0061] In preparation example 8, the cooling rate is 7±2℃ / min.

[0062] In preparation example 9, the cooling rate is 23±2℃ / min.

[0063] The remaining raw materials and the preparation method of the weighting agent in the above preparation examples are the same as those in preparation example 3.

[0064] Preparation examples 10-13.

[0065] Preparation examples 10-13 respectively provide a weighting agent for preparing concrete.

[0066] The difference between the above preparation example and preparation example 3 is that the type of HSH polyether polyol in the weighting agent is different, which is shown as follows.

[0067] In preparation example 10, the model specification of HSH polyether polyol is HSH-204, the hydroxyl value is 265-300 mgKOH / g, and the acid value is ≤0.15 mgKOH / g.

[0068] In preparation example 11, the model specification of HSH polyether polyol is HSH-206, the hydroxyl value is 178-197 mgKOH / g, and the acid value is ≤0.15 mgKOH / g.

[0069] In Preparation Example 12, the model specification of HSH polyether polyol is HSH-215, the hydroxyl value is 68-83 mgKOH / g, and the acid value is ≤0.15 mgKOH / g.

[0070] In Preparation Example 13, the model specification of HSH polyether polyol is HSH-220, the hydroxyl value is 53-59 mgKOH / g, and the acid value is ≤0.15 mgKOH / g.

[0071] The preparation methods of the remaining raw materials and weighting agents in the above preparation example are the same as those in Preparation Example 3.

[0072] Preparation Examples 14-17.

[0073] Preparation Examples 14-17 respectively provide a weighting agent for preparing concrete.

[0074] The difference between the above preparation example and preparation example 3 is that the amount of each raw material in the weighting agent is different, as shown in Table 2.

[0075] The preparation methods of the weighting agents in the above preparation examples are the same as those in Preparation Example 3.

[0076] Table 2 Amount of each raw material in the weighting agent in Preparation Examples 3, 14-17

[0077]

[0078] Preparation Example 18.

[0079] This preparation example provides a weighting agent for preparing concrete.

[0080] The preparation method of the weighting agent in this preparation example is:

[0081] Calcium carbonate and sawdust raw materials are uniformly mixed in a weight ratio of 11:100 to obtain calcium-based sawdust. 25 g of calcium-based sawdust, 8 g of HSH polyether polyol (model specification: HSH-210, hydroxyl value: 105-119 mgKOH / g, acid value: ≤0.15 mgKOH / g), 80 g of iron ore, and 15 g of nano-iron powder are weighed and uniformly mixed to obtain a counterweight.

[0082] Preparation Example 19.

[0083] This preparation example provides a weighting agent for preparing concrete.

[0084] The difference between this preparation example and preparation example 3 is that calcium sulfate is used instead of calcium carbonate in the preparation method of calcium-based carbonized sawdust.

[0085] The remaining raw materials of the weighting agent and its preparation method in this preparation example are the same as those in Preparation Example 3.

[0086] Preparation Example 20.

[0087] The present preparation example provides a weighting agent for preparing concrete.

[0088] The present preparation example differs from Preparation Example 3 in that calcium oxide is used instead of calcium carbonate in the preparation method of the calcium-based carbonized wood flour.

[0089] The remaining raw materials of the weighting agent and the preparation method thereof in the present preparation example are the same as those in Preparation Example 3.

[0090] Preparation Example 21.

[0091] The present preparation example provides a weighting agent for preparing concrete.

[0092] The present preparation example differs from Preparation Example 3 in that HyPer H403 hydroxyl-terminated hyperbranched polyester (model specification HSH-210, hydroxyl value 160 mgKOH / g, purchased from Wuhan Hyperbranched Resin Technology Co., Ltd.) is used instead of HSH polyether polyol.

[0093] The remaining raw materials of the weighting agent and the preparation method thereof in the present preparation example are the same as those in Preparation Example 3.

[0094] Examples

[0095] Examples 1-13.

[0096] Examples 1-13 each provide a weighted concrete.

[0097] The weighted concrete in the above examples differs in that the source of the weighting agent is different, as shown in Table 3.

[0098] The preparation method of the weighted concrete in the above examples is as follows:

[0099] (1) 110 g of P.O 22.5 ordinary portland cement and 215 g of the weighting agent were weighed and mixed uniformly to obtain dry materials.

[0100] (2) 0.1 g of polycarboxylic acid water reducer, 0.05 g of defoaming agent (model XWC-0285 powder / T112), 0.05 g of thickening agent (model Rheovis PU 1190), and 50 g of water were mixed uniformly to obtain a mixed solution.

[0101] (3) The mixed solution was added to the dry materials, and stirred for 45 s to obtain a weighted concrete.

[0102] (4) The weighted concrete was placed in a mold, and molded, demolded, and cured to obtain a concrete weight block.

[0103] Table 3 Sources of the weighting agent in Examples 1-13

[0104]

[0105] Example 14.

[0106] This embodiment provides a counterweight concrete.

[0107] The difference between this embodiment and embodiment 2 is that the amount of the weighting agent used is 206 g.

[0108] Example 15.

[0109] This embodiment provides a counterweight concrete.

[0110] The difference between this embodiment and embodiment 2 is that the amount of the weighting agent used is 228 g.

[0111] Comparative Example.

[0112] Comparative Example 1.

[0113] This comparative example provides a concrete.

[0114] The preparation method of concrete in this comparative example is:

[0115] (1) Weigh 110 g of PO 22.5 ordinary Portland cement and 49 g of iron ore and mix them evenly to obtain dry material;

[0116] (2) 0.1 g of polycarboxylic acid water reducer, 0.05 g of defoamer (model XWC-0285 powder / T112), 0.05 g of thickener (model Rheovis PU 1190) and 50 g of water were mixed to obtain a mixed solution;

[0117] (3) Add the mixed solution to the dry material and stir for 45 seconds to obtain the counterweight concrete;

[0118] (4) Place it in a mold, perform molding, demoulding, and curing to obtain a concrete counterweight block.

[0119] Comparative Examples 2-9.

[0120] Comparative Examples 2-9 each provide a concrete.

[0121] The difference between the weighted concrete in the comparative example and that in Example 2 is that the source of the weighting agent is different, as shown in Table 4.

[0122] Table 4 Sources of weighting agents in Comparative Examples 2-9

[0123]

[0124] Performance testing

[0125] The concrete in Examples 1-15 and Comparative Examples 1-9 were used as test objects, and their properties were tested using the following test methods.

[0126] (1) Bulk density

[0127] The test is carried out in accordance with GB / T50080-2016 "Standard for Test Methods of Performance of Ordinary Concrete Mixtures".

[0128] (2) Slump of concrete

[0129] The test is carried out in accordance with GB / T50080-2016 "Standard for Test Methods of Performance of Ordinary Concrete Mixtures".

[0130] (3) Mechanical properties of concrete

[0131] According to GB / T50081-2016 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete", the compressive strength of standard test blocks was tested after 7 days and 28 days of curing.

[0132] (4) Durability of concrete

[0133] The test specimens were placed in a constant temperature and humidity test chamber for high and low temperature testing. They were placed in an environment with a temperature of -20°C and a humidity of 0% for 24 hours; and in an environment with a temperature of 120°C and a humidity of 50% for 24 hours. Then, the test was carried out in accordance with the "GBT 50082-2009 Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete", and the crack area per unit area of ​​the counterweight concrete was detected to evaluate its crack resistance.

[0134] Test results: as shown in Table 5.

[0135] Table 5 Performance test results of samples in Examples 1-15 and Comparative Examples 1-9

[0136]

[0137] Combined with the test results of Table 5, by comparing the test results of Examples 1-15 with those of Comparative Examples 1-9, the present application carbonizes the raw material obtained by mixing calcium carbonate and sawdust, and then uses it in combination with HSH polyether polyol, iron ore, and nano iron powder to obtain a weighting agent. The weighting agent is used to prepare weighted concrete, which can increase the concrete bulk density while ensuring the strength of the concrete, and the concrete has good crack resistance.

[0138] In Comparative Example 1, calcium-based carbonized sawdust and HSH polyether polyol were not used as weighting agents, and the bulk density of the obtained ordinary concrete was only 2630 Kg / m 3 , and the concrete's crack resistance is poor.

[0139] In Comparative Example 6, the calcium carbonate and wood chips were not subjected to carbonization treatment, and the obtained concrete had a bulk density of only 3020 Kg / m 3 , and the concrete had poor compressive strength and crack resistance.

[0140] From the test results of Comparative Example 2 and Comparative Examples 7-8, it can be seen that, in the method for preparing calcium-based carbonized wood chips, the present application selects to use calcium carbonate, and the performance of the concrete prepared by using the weighting agent obtained is more excellent, as compared to selecting to use calcium sulfate or calcium oxide. Further, from the test results of Comparative Examples 1-3 and Comparative Examples 2-3, it can be seen that, by controlling the weight ratio of calcium carbonate to wood chips to be (8-14): 100, the bulk density and mechanical properties of the weighted concrete can be further improved.

[0141] Meanwhile, from the test results of Comparative Examples 2, 4-7, it can be seen that, in the method for preparing calcium-based carbonized wood chips, the heating rate and the cooling rate of the carbonization process will both affect the role of the weighting agent in the concrete, and through multiple tests, the present application controls the specific process parameters to be: heating the raw materials from room temperature to 830-900℃ at a heating rate of 5-10℃ / min, carbonizing for 2h, and then cooling to room temperature at a cooling rate of 10-20℃ / min, to obtain the carbonized product.

[0142] From the test results of Comparative Example 2 and Comparative Example 9, it can be seen that, as compared to selecting to use HyPer H403 hydroxyl-terminated hyperbranched polyester, the present application selects to use HSH polyether polyol, which can significantly improve the performance of the concrete. Further, from the test results of Comparative Example 2 and Examples 8-11, the present application selects to use HSH polyether polyol having a hydroxyl value of 60-200 mgKOH / g, which can further improve the performance of the concrete.

[0143] From the test results of Comparative Example 2, 12-13 and Comparative Examples 4-5, it can be seen that, the amount of each raw material in the weighting agent has a great influence on the performance of the weighted concrete, and therefore, the present application controls the addition amount of each raw material to be: calcium-based carbonized wood chips 20-30 parts, HSH polyether polyol 5-12 parts, iron ore sand 76-84 parts, and nano-iron powder 12-19 parts.

[0144] Although the present application has been described in detail by the general description and specific embodiments above, some modifications or improvements can be made on the basis of the present application, which will be apparent to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of protection claimed by the present application.

Claims

1. A weighting agent for preparing concrete, characterized in that: Specifically, it includes the following components by weight: 20-30 parts of calcium-based carbonized sawdust, 5-12 parts of HSH polyether polyol, 76-84 parts of iron ore, and 12-19 parts of nano iron powder; The preparation method of the calcium-based carbonized sawdust comprises: mixing calcium carbonate and sawdust raw materials in a weight ratio of (8-14):100, carbonizing and crushing the mixture in an anaerobic manner; the anaerobic carbonization step comprises: heating the raw materials from room temperature to 830-900°C at a heating rate of 5-10°C / min under anaerobic conditions, carbonizing for 2-3 hours, and then cooling the mixture to room temperature at a cooling rate of 10-20°C / min to obtain a carbonized product; The HSH polyether polyol has a hydroxyl value of 60-200 mgKOH / g and an acid value of ≤0.15 mgKOH / g.

2. The weighting agent for preparing concrete according to claim 1, characterized in that: Specifically, the method comprises the following components in parts by weight: 24-28 parts of calcium-based carbonized sawdust, 7-10 parts of HSH polyether polyol, 78-82 parts of iron ore, and 13-17 parts of nano iron powder.

3. The weighting agent for preparing concrete according to claim 1, characterized in that: The apparent density of the iron ore is: 4.2-5.2g / cm 3 , particle size is 0.01-2 mm.

4. The weighting agent for preparing concrete according to claim 1, characterized in that The particle size of the nano iron powder is 800±100 nm.

5. Use of the weighting agent according to any one of claims 1 to 4 in preparing concrete.

6. A counterweight concrete, characterized in that: Specifically, the invention comprises the following components in parts by weight: 100-120 parts of cement, 206-228 parts of the weighting agent for preparing concrete according to any one of claims 1-4, 0.06-0.12 parts of a water reducer, 0.01-0.08 parts of a defoaming agent, 0.02-0.12 parts of a thickener, and 40-60 parts of water.

7. The method for preparing counterweight concrete according to claim 6, wherein: The specific steps include: Mixing the cement and the weighting agent uniformly to obtain dry material; uniformly dispersing the water reducing agent, the defoaming agent, and the thickener in the water to obtain a mixed solution; The mixed solution is added to the dry material and stirred for 30-60 seconds to obtain the counterweight concrete.

8. Use of the counterweight concrete according to claim 6 in a bridge box girder counterweight component or a building anti-floating counterweight component.

Images