A foamed concrete and a method of making the same

Abstract

The application belongs to the technical field of building materials, and particularly relates to a foamed concrete and a preparation method thereof. The foamed concrete comprises the following components in parts by weight: 40-60 parts of pretreated stone chippings, 5-6 parts of a foaming agent, 5-8 parts of a foam stabilizer, 5-7 parts of fly ash, 10-20 parts of cement, 2-5 parts of silica ash and 10-35 parts of water; the pretreated stone chippings are obtained by fine grinding and high-temperature ion activation of stone chippings. The foamed concrete with light weight and high strength is prepared by using TBM stone chippings as the main raw material, combining the composition structure and physicochemical properties of the stone chippings, and through fine grinding, shaping and surface activation treatment under the action of a compounded foaming agent, so that the problems of low strength and difficult foam stabilization of general foamed concrete are solved, and the problems of poor application channel, low utilization rate, environmental pollution by waste, time-consuming, labor-consuming and energy-consuming in the treatment of TBM stone chippings are solved, the utilization rate of waste is improved, and the building material cost is saved.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to foamed concrete and its preparation method. Background Technology

[0002] TBM (Tunnel Boring Machine) construction technology has been widely applied to large-scale long tunnel projects in industries such as railways, highways, water conservancy, and urban subways. Discarding the excavated material as waste not only impacts the environment but also wastes resources and increases project investment. Currently, the comprehensive utilization of TBM excavated material is beginning to be applied in highway and railway engineering. High-strength, appropriately sized hard rock is used as concrete aggregate, while other materials are tested to determine their suitability for slope protection and roadbed filling. Unsuitable soil and soft rock materials can be modified with cement or lime to meet roadbed filling requirements. However, overall, the utilization rate of tunnel spoil is low, and in-depth utilization is not possible, especially for stone chips (particles smaller than 5mm), which are mixed with large amounts of stone powder and fine sand. These are primarily treated as waste and not effectively utilized. Currently, the development and utilization of waste stone powder in the construction field mainly includes its use as admixtures or coarse and fine aggregates. Using waste stone powder as an admixture to replace cement can reduce the cement content in concrete, and the replacement amount is relatively small. However, stone powder as an admixture is often inert, making it difficult to achieve high dosage utilization. Summary of the Invention

[0003] The purpose of this invention is to provide a high-strength, low-cost foamed concrete and its preparation method.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A foamed concrete comprising the following components by weight: 40-60 parts pretreated stone chips, 5-6 parts foaming agent, 5-8 parts foam stabilizer, 5-7 parts fly ash, 10-20 parts cement, 2-5 parts silica fume, and 10-35 parts water.

[0006] The pretreated stone chips are obtained by grinding and high-temperature ion activation of stone chips.

[0007] In one preferred embodiment, the stone chips are stone chips generated during the construction of a full-face tunnel boring machine, and the particle size of the stone chips is less than 5 mm.

[0008] In one preferred embodiment, the stone chips contain 30%-50% stone powder by weight.

[0009] This invention provides a novel solution for preparing foamed concrete using TBM (Tunnel Boring Machine) chips generated during full-face tunnel boring machine (TBM) construction. Specifically, it uses TBM chips with a particle size of less than 5mm as the main raw material. Combining the chip's inherent structure and physicochemical properties, lightweight, high-strength foamed concrete is prepared through fine grinding, shaping, and surface activation treatment, followed by the application of a compound foaming agent. This solution addresses the problems of low strength and difficulty in stabilizing foam in conventional foamed concrete, while also resolving issues such as limited application avenues for TBM chips, low utilization rate, environmental pollution from waste, and time-consuming, labor-intensive, and energy-intensive waste treatment. It improves waste utilization and saves on building material costs.

[0010] In one preferred embodiment, the roundness of the finely ground stone chips is not less than 0.94.

[0011] The higher the roundness of the particles, the better the water retention and foam stabilization effect of the foamed concrete.

[0012] In one preferred embodiment, the specific surface area of ​​the finely ground stone chips is 400-500 m². 2 / kg.

[0013] For particles of the same mass, the rounder they are, the smaller their specific surface area. Therefore, the specific surface area must also take into account water retention and foam stabilization. An excessively small specific surface area is detrimental to subsequent activation steps, while an excessively large specific surface area will lead to an increase in cementitious materials and a decrease in the strength of the foamed concrete, as well as a decline in water retention and foam stabilization.

[0014] In one preferred embodiment, the fineness modulus of the ground stone chips is 1.5-2.0, and the average particle size is 0.25-0.30 mm.

[0015] Because smaller fineness modulus and average particle size of foamed concrete aggregates result in better foam stability, and smaller particle size and larger specific surface area lead to more active sites during subsequent surface activation. However, excessively small fineness modulus and average particle size of foamed concrete aggregates can lead to a decrease in strength, so it is necessary to control the particle size and specific surface area within a suitable range.

[0016] In one preferred embodiment, the grinding is performed by grinding a stone chipping rod for 20-30 minutes to obtain finely ground stone chips.

[0017] The purpose of rod milling is to obtain stone chips with both good particle shape and size.

[0018] In one preferred embodiment, the grinding is performed by processing the stone chips through an overflow rod mill for 20-30 minutes.

[0019] In one preferred embodiment, the feed rate of the overflow rod mill is controlled at 100~150kg / h, the power is controlled at 1~2Kw, the water pressure is controlled at 0.1-0.2MPa, and the rod loading is 18~20kg.

[0020] In one preferred embodiment, the high-temperature ion activation involves calcining the finely ground stone chips at 500-600 ℃ for 1-2 hours to obtain calcined stone chips, followed by positive ionization treatment.

[0021] At this temperature, the stone chips can be effectively activated without damaging their internal structure.

[0022] In one preferred embodiment, the positive ionization treatment involves placing the calcined stone chips into an oven equipped with a positive ion generator and treating them for at least 20 minutes.

[0023] In one preferred embodiment, the positive ion generator has a power of 10-20 kW and an ion concentration > 8.0 × 10⁻⁶. 8 icon / cm 3 .

[0024] The power and ion concentration of the positive ion generator are within a suitable range to ensure that the surface of the stone chips is fully activated.

[0025] In one preferred embodiment, the foaming agent comprises, by weight, 0.5-1.0 parts of alkyl polyoxyethylene ether ammonium sulfate foaming agent, 8-10 parts of NaCl, and 89-95 parts of water.

[0026] NaCl can promote the hydrolysis of foaming agents, and the foaming effect is best under this parameter.

[0027] In one preferred embodiment, the density of the alkyl polyoxyethylene ether ammonium sulfate blowing agent is 1.0-1.1 g / cm³. 3 pH value 9.2~10, foaming ratio greater than 20.

[0028] In one preferred embodiment, the foam stabilizer comprises, by weight, 1.0-1.5 parts of anionic surfactant polyacrylamide, 0.042-0.084 parts of carboxymethyl cellulose, 1-2 parts of terephthalamide and 90-97 parts of water.

[0029] Compound foam stabilizers are most effective. Carboxymethyl cellulose and terephthalamide are nonionic surfactants, and when compounded with anionic foam stabilizers, they produce good results.

[0030] In one preferred embodiment, the fly ash has a specific surface area of ​​200-230 m². 2 / kg; water requirement ratio less than 110%. Excessive specific surface area of ​​fly ash leads to increased water requirement, while insufficient specific surface area hinders foam stabilization.

[0031] In one preferred embodiment, the cement is ordinary silicate cement.

[0032] In one preferred embodiment, the specific surface area of ​​the silica fume is no greater than 20 m². 2 / kg.

[0033] Silica fume primarily serves to stabilize bubbles, therefore its specific surface area should not be too small.

[0034] In one preferred embodiment, the silica fume comprises: 75-98 parts SiO2, 0.8-1.5 parts Al2O3 and 0.6-1.2 parts Fe2O3.

[0035] The present invention also includes a method for preparing the foamed concrete, comprising the following steps:

[0036] S1. Mix the foaming agent and part of the foam stabilizer, foam, and obtain pre-made foam;

[0037] S2. Mix the remaining raw materials and stir evenly to obtain a neat paste; then add pre-made foam, stir evenly, and then mold and cure to obtain foamed concrete.

[0038] In one preferred embodiment, the curing process conditions for step S2 are: relative humidity greater than 90% and temperature of 20±5℃.

[0039] The present invention will be further explained below:

[0040] This invention improves the compatibility of stone chips with foaming agents and foam stabilizers by increasing the specific surface area and activation points of the stone chips through fine grinding and high-temperature ion activation technology. Furthermore, the non-destructive ion activation, combined with the optimal particle shape and specific surface area of ​​the stone chips, enables the foamed concrete to achieve a 28-day strength of C3. The positively activated stone chips bind tightly to the polyacrylamide molecules, the main component of the foam stabilizer. The combination of alkyl polyoxyethylene ether ammonium sulfate foaming agents and anionic polyacrylamide molecules in the foam stabilizer achieves optimal foaming and stabilizing effects. Carboxymethyl cellulose and terephthalamide primarily function as thickeners, dispersants, and foam stabilizers. Fly ash improves the fluidity of cement paste, while silica fume reduces the surface tension of the bubble film, thus achieving a foam stabilizing effect and enabling the foamed concrete to achieve excellent workability.

[0041] The beneficial effects of this invention are as follows:

[0042] (1) Providing new ideas and methods for the utilization of TBM stone chips: TBM stone chips have problems such as poor particle shape, poor gradation and low utilization rate as aggregates. This invention provides a reference for the utilization technology of such waste.

[0043] (2) Reduce the problem of poor foam stabilization effect: The foam stabilization effect is optimized by TBM stone chip surface activation, surfactant compounding and other technologies.

[0044] (3) Reduced cost and excellent performance: The present invention uses TBM stone chips to prepare lightweight and high-strength foamed concrete with a dry density grade of A06 and a 28-day compressive strength grade of C3.5, which improves the comprehensive utilization rate of TBM tunnel excavation materials and saves building material costs. The preparation method provided by the present invention is simple and easy to scale up, and has significant economic value. Detailed Implementation

[0045] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited to the scope shown in the embodiments. These embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0046] The TBM excavation rock chips used in this embodiment of the invention are granite, with a stone powder weight fraction of 30%-50% and a particle size of less than 5mm. The fine-grained fly ash used has a specific surface area of ​​200m². 2 / kg, water requirement ratio is 105%, cement used is Conch brand P·O42.5 cement, silica fume specific surface area is 20m² 2 / kg, composed of 90% SiO2, 1.0% Al2O3, and 0.9% Fe2O3.

[0047] Example 1

[0048] The specific steps for preparing a high-utilization, high-strength, low-density, and low-cost TBM stone chip foam concrete are as follows:

[0049] First, the TBM excavation chips are pretreated. Pretreatment involves processing 30 kg of TBM excavation chips (maximum particle size not exceeding 5 mm) using an overflow rod mill for 20 minutes. The overflow rod mill feed rate is controlled at 100 kg / h, power at 1 kW, water pressure at 0.1 MPa, and rod loading at 18 kg. After pretreatment, the specific surface area of ​​the TBM excavation chips is controlled to be 400 m². 2 / kg, fineness modulus controlled at 2.0, roundness controlled at 0.95.

[0050] The stone chips obtained after rod milling were first placed in a muffle furnace at 550℃ for 2 hours, and then treated in an oven equipped with a positive ion generator for more than 30 minutes. The positive ion generator had a power of 10 kW and an ion concentration of 9.0 × 10⁻⁶. 8 icon / cm 3 .

[0051] Weigh out 55 parts of TBM stone chips, 5 parts of compound foaming agent, 5 parts of compound foam stabilizer, 5 parts of fine fly ash, 10 parts of cement, 2 parts of silica fume, and 18 parts of water. The compound foaming agent is a mixture of nonionic ADF-1 foaming agent, NaCl, and water, with an ADF-1 foaming agent concentration of 0.5%, a NaCl concentration of 8%, and a density of 1.05 g / cm³. 3 The pH value is 9.5, and the foaming ratio is greater than 20. The compound foam stabilizer consists of anionic surfactant HPAM, carboxymethyl cellulose, terephthalamide, and water, with HPAM concentration of 1.0%, carboxymethyl cellulose concentration of 0.01 mol / L, and terephthalamide concentration of 1%. The compound foaming agent and 2.5 parts of the compound foam stabilizer are diluted 10 times and then used to obtain pre-formed foam using a foaming agent mechanism. Pretreated TBM stone chips, the remaining 2.5 parts of foam stabilizer, fine fly ash, silica fume, cement, and water are mixed and stirred evenly to obtain a neat slurry. Then, the above-mentioned pre-formed foam is added, stirred evenly, and then molded. The curing conditions are: relative humidity > 90% and temperature 20 ± 1℃ to obtain foamed concrete.

[0052] Example 2

[0053] The specific steps for preparing a high-utilization, high-strength, low-density, and low-cost TBM stone chip foam concrete are as follows:

[0054] First, the TBM stone chips are pre-treated by passing 50 kg of TBM excavation stone chips with a maximum particle size of no more than 5 mm through an overflow rod mill for 25 minutes. The feed rate of the overflow rod mill is controlled at 130 kg / h, the power is controlled at 1.5 kW, the water pressure is controlled at 0.1 MPa, and the rod loading is 19 kg. The specific surface area of ​​the stone chips is controlled at 450 m². 2 / kg, fineness modulus controlled at 1.7, and roundness controlled at 0.95.

[0055] Stone chips obtained after rod milling were first placed in a muffle furnace at 600℃ for 1.5 hours, and then treated in an oven equipped with a positive ion generator for more than 30 minutes. The positive ion generator had a power of 20 kW and an ion concentration of 9.5 × 10⁻⁶. 8 icon / cm 3 .

[0056] Weigh out 50 parts of TBM stone chips, 5.5 parts of compound foaming agent, 6 parts of compound foam stabilizer, 6 parts of fine fly ash, 15 parts of cement, 2 parts of silica fume, and 15.5 parts of water. The compound foaming agent is a mixture of nonionic ADF-1 foaming agent, NaCl, and water. The concentration of ADF-1 foaming agent is 0.7%, the concentration of NaCl is 9%, and the density of ADF-1 foaming agent is 1.05 g / cm³. 3The pH value is 9.5, and the foaming ratio is greater than 20. The compound foam stabilizer consists of anionic surfactant HPAM, carboxymethyl cellulose, terephthalamide, and water. The concentration of HPAM is 1.1%, the concentration of carboxymethyl cellulose is 0.015 mol / L, and the concentration of terephthalamide is 1.5%. The compound foaming agent and 3 parts of the compound foam stabilizer are diluted 10 times and then pre-formed foam is obtained by using a foaming agent mechanism. Pretreated TBM stone chips, the remaining 3 parts of foam stabilizer, fine fly ash, silica fume, cement, and water are mixed and stirred evenly to obtain a neat slurry. Then, the above pre-formed foam is added, stirred evenly, and then shaped. The curing process conditions are: relative humidity > 90% and temperature 20±1℃ to obtain foamed concrete.

[0057] Example 3

[0058] The specific steps for preparing a high-utilization, high-strength, low-density, and low-cost TBM stone chip foam concrete are as follows:

[0059] First, the TBM stone chips are pre-treated. Pre-treatment involves passing 50 kg of TBM excavation stone chips with a maximum particle size not exceeding 5 mm through an overflow rod mill for 30 minutes. The overflow rod mill feed rate is controlled at 150 kg / h, power at 2 kW, water pressure at 0.2 MPa, and rod loading at 20 kg. The specific surface area of ​​the stone chips is controlled to be 500 m². 2 / kg, fineness modulus controlled at 1.5, roundness controlled at 0.95.

[0060] The stone chips obtained after rod milling were first placed in a muffle furnace at 600℃ for 1.5 hours, and then treated in an oven equipped with a positive ion generator for more than 30 minutes. The positive ion generator had a power of 15 kW and an ion concentration of 8.5 × 10⁻⁶. 8 icon / cm 3 .

[0061] Weigh out 40 parts TBM stone chips, 6 parts foaming agent, 8 parts compound foam stabilizer, 7 parts fine fly ash, 20 parts cement, 3 parts silica fume, and 16 parts water. The foaming agent is a mixture of nonionic ADF-1 foaming agent, NaCl, and water. The concentration of ADF-1 foaming agent is 1.0%, the concentration of NaCl is 10%, and the density of ADF-1 foaming agent is 1.05 g / cm³. 3The pH value is 10, and the foaming ratio is greater than 20. The compound foam stabilizer consists of anionic surfactant HPAM, carboxymethyl cellulose, terephthalamide, and water. The concentration of HPAM is 1.2%, the concentration of carboxymethyl cellulose is 0.02 mol / L, and the concentration of terephthalamide is 2%. The foaming agent and 4 parts of the compound foam stabilizer are diluted 10 times and then pre-formed foam is obtained by foaming agent mechanism. Pretreated TBM stone chips, the remaining 4 parts of foam stabilizer, fine fly ash, silica fume, cement, and water are mixed and stirred evenly to obtain a neat slurry. Then, the above pre-formed foam is added, stirred evenly, and then shaped. The curing process conditions are: relative humidity > 90% and temperature 20±1℃ to obtain foamed concrete.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 is that the amount of pretreated TBM stone chips is 60 parts and cement is 5 parts, while the rest is the same as in Example 1.

[0064] Comparative Example 2

[0065] The difference between this comparative example and Example 1 is that the amount of pretreated TBM stone chips is 20 parts and the amount of cement is 45 parts. Everything else is the same as in Example 1.

[0066] Comparative Example 3

[0067] The difference between this comparative example and Example 1 lies in the specific steps of the preparation method for the foamed concrete. In this example, the compound foaming agent and 5 parts of compound foam stabilizer are diluted 10 times and then pre-formed foam is obtained using a foaming agent mechanism. Pretreated TBM stone chips, fine fly ash, silica fume, cement, and water are mixed and stirred evenly to obtain a neat slurry. Then, the above-mentioned pre-formed foam is added, stirred evenly, and molded. The curing conditions are: relative humidity > 90% and temperature 20 ± 1℃ to obtain foamed concrete. All other aspects are the same as in Example 1.

[0068] Comparative Example 4

[0069] The difference between this comparative example and Example 1 is that the TBM stone chips, after being pretreated by a rod mill, are directly subjected to the ion activation step without being placed in a muffle furnace at 550°C for 2 hours. Otherwise, they are the same as in Example 1.

[0070] Comparative Example 5

[0071] The difference between this comparative example and Example 1 is that the TBM stone chips, after being pretreated by a rod mill, are directly mixed with other materials in a muffle furnace at 550°C for 2 hours without undergoing an ion activation step. Otherwise, it is the same as Example 1.

[0072] Comparative Example 6

[0073] The difference between this comparative example and Example 1 is that the TBM stone chips are not pretreated by rod milling, but are directly processed in a muffle furnace at 550°C for 2 hours, followed by an ion activation step. Otherwise, it is the same as Example 1.

[0074] Comparative Example 7

[0075] The difference between this comparative example and Example 1 is that the foam stabilizer is a mixture of anionic surfactant HPAM and water, and it does not contain carboxymethyl cellulose or terephthalamide. The HPAM concentration is 1.0%. Everything else is the same as in Example 1.

[0076] Comparative Example 8

[0077] The difference between this comparative example and Example 1 is that the foam stabilizer is a mixture of anionic surfactant HPAM, carboxymethyl cellulose, and water, and it does not contain terephthalamide. Everything else is the same as in Example 1. The HPAM concentration is 1.0%, and the carboxymethyl cellulose concentration is 0.01 mol / L.

[0078] Comparative Example 9

[0079] The difference between this comparative example and Example 1 is that the foaming agent is a mixture of nonionic ADF-1 foaming agent and water, without NaCl. Everything else is the same as in Example 1. The HPAM concentration is 1.0%, and the ADF-1 foaming agent concentration is 0.5%.

[0080] Comparative Example 10

[0081] The difference between this comparative example and Example 1 is that the compound foam stabilizer is composed of cationic surfactant SDS, carboxymethyl cellulose, terephthalamide, and water. The concentration of cationic surfactant SDS is 1.0%, the concentration of carboxymethyl cellulose is 0.01 mol / L, and the concentration of terephthalamide is 1%. Everything else is the same as in Example 1.

[0082] Comparative Example 11

[0083] The difference between this comparative example and Example 1 is that the rod milling time is 50 minutes, resulting in a stone chip specific surface area of ​​300 m². 2 / kg, fineness modulus is 1.3, average particle size is 0.2, roundness is 0.90, and other parameters are the same as in Example 1.

[0084] Comparative Example 12

[0085] The difference between this comparative example and Example 1 is that the rod milling time is 5 minutes, resulting in a stone chip specific surface area of ​​650 m². 2 / kg, fineness modulus is 2.8, average particle size is 0.46, roundness is 0.81, and other parameters are the same as in Example 1.

[0086] Comparative Example 13

[0087] The difference between this comparative example and Example 1 is that the high-temperature treatment step is performed at a temperature of 800°C, while the rest is the same as Example 1.

[0088] Comparative Example 14

[0089] The difference between this comparative example and Example 1 is that the high-temperature treatment step is performed at a temperature of 400°C, while the rest is the same as Example 1.

[0090] Comparative Example 15

[0091] The difference between this comparative example and Example 1 is that the ion concentration of the positive ion generator is 6.0 × 10⁻⁶. 8 icon / cm 3 Everything else is the same as in Example 1.

[0092] The 3-day, 7-day, and 28-day compressive strengths of the foamed concrete prepared in each example and comparison were tested according to the standard GB / T 11969-2008. The performance evaluation is shown in Table 1.

[0093]

[0094] As can be seen from the performance evaluation data of the embodiments in Table 1, the dry density of the foamed concrete prepared in the embodiments of the present invention reaches 664-705 kg / m3, the 3-day compressive strength reaches 1.63-1.68 MPa, the 7-day compressive strength reaches 2.13-2.33 MPa, and the 28-day compressive strength reaches 3.46-4.62 MPa. The dry density grade can reach A07, and the compressive strength grade reaches C3.5.

[0095] As can be seen from the comparative performance evaluation data in Table 1, Comparative Example 1 had less foam and a dry density as high as 886 kg / m³ due to excessive stone chips and insufficient cement content. 3In the case of Comparative Example 1, the strength was very low; Comparative Example 2 had too much stone chips, resulting in excessive cement content, increased water demand, and the water in the foam was absorbed by the cementitious material and broken down, ultimately increasing the dry density of the concrete; Comparative Example 3 lacked the mixing process of compound foam stabilizer with raw materials such as stone chips, resulting in poor adsorption effect of foam stabilizer molecules on the surface of stone chips and other particles, poor foam stability, and thus increased dry density of foamed concrete; Comparative Examples 4 and 5 lacked high temperature or ion activation process, resulting in decreased foam stabilization effect and reduced bonding ability between stone chips and cement hydration products, leading to low dry density and no significant increase in strength; Comparative Example 6 lacked stone chip rod grinding, which not only affected the subsequent activation steps but also increased the roundness of the stone chip surface, decreased the foam stabilization effect, and increased dry density; Comparative Example 7 lacked carboxymethyl cellulose and terephthalamide in the foam stabilizer, resulting in decreased foam stabilization effect, increased dry density, and slightly increased strength; Comparative Example 8 lacked terephthalamide... The amine slightly improved the foam stabilizing effect compared to Example 7, but it was still worse overall than the Example 9. The lack of NaCl in Comparative Example 9 resulted in poorer hydrolysis of the nonionic surfactant, leading to a poorer foaming effect and increased dry density of the concrete. In Comparative Example 10, the foam stabilizer was a cationic surfactant, which has worse compatibility with nonionic surfactants than anionic surfactants, resulting in a higher dry density of the final foamed concrete. In Comparative Example 11, the excessively long rod milling time resulted in overly fine stone chips, significantly affecting its strength. In Comparative Example 12, the excessively short rod milling time resulted in overly coarse stone chips, leading to a poor foam stabilizing effect and a higher dry density of the foamed concrete. In Comparative Example 13, the excessively high activation temperature damaged the structure of the stone chips, causing a decrease in the strength of the foamed concrete. In Comparative Example 14, the excessively low activation temperature resulted in poor surface activity of the stone chips, limiting the foam stabilizing effect and resulting in a higher dry density. In Comparative Example 15, the excessively low concentration of positive ions also led to poor stone chip activation and a higher dry density.

[0096] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention. Furthermore, it should be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. In addition, various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the spirit of the present invention, they should also be considered as the content disclosed by the present invention.

Claims

1. A type of foamed concrete, characterized in that, It includes the following components by weight: 40-60 parts pretreated stone chips, 5-6 parts foaming agent, 5-8 parts foam stabilizer, 5-7 parts fly ash, 10-20 parts cement, 2-5 parts silica fume and 10-35 parts water; The pretreated stone chips are obtained by grinding stone chips and ion activation at high temperature. The roundness of the finely ground stone chips is not less than 0.94; the specific surface area is 400~500 m². 2 / kg; fineness modulus is 1.5-2.0, average particle size is 0.25-0.30mm; The high-temperature ion activation involves calcining the finely ground stone chips at 500-600℃ for 1-2 hours to obtain calcined stone chips, followed by positive ionization treatment. The foaming agent comprises 0.5-1.0 parts of a nonionic surfactant alkyl polyoxyethylene ether ammonium sulfate foaming agent, 8-10 parts of NaCl, and 89-95 parts of water; The foam stabilizer includes 1.0-1.5 parts of anionic surfactant polyacrylamide, 0.042-0.084 parts of carboxymethyl cellulose, 1-2 parts of terephthalamide, and 90-97 parts of water; The foamed concrete is prepared by a method comprising the following steps: S1. Mix the foaming agent and part of the foam stabilizer, foam, and obtain pre-made foam; S2. Mix the remaining raw materials and stir evenly to obtain a neat paste; then add the precast foam, stir evenly, and then mold and cure to obtain foamed concrete. The positive ionization treatment involves placing the calcined stone chips into an oven equipped with a positive ion generator, where the ion concentration of the positive ion generator is >8.0 × 10⁻⁶. 8 icon / cm 3 .

2. The foamed concrete according to claim 1, characterized in that, The grinding process involves grinding a stone chipping rod for 20-30 minutes to obtain finely ground stone chips.

3. The foamed concrete according to claim 1, characterized in that, The grinding process involves processing the stone chips through an overflow rod mill for 20-30 minutes.

4. The foamed concrete according to claim 3, characterized in that, The feed rate of the overflow rod mill is controlled at 100~150kg / h, the power is controlled at 1~2kW, the water pressure is controlled at 0.1-0.2MPa, and the rod loading is 18~20kg.

5. The foamed concrete according to claim 1, characterized in that, The positive ionization treatment involves placing the calcined stone chips into an oven equipped with a positive ion generator and treating them for at least 20 minutes.

6. The foamed concrete according to claim 5, characterized in that, The power of the positive ion generator is 10-20kW.

7. The foamed concrete according to any one of claims 1-6, characterized in that, The specific surface area of ​​the fly ash is 200~230m². 2 / kg; the water requirement ratio of fly ash is less than 110%.

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