Formula and preparation method of foam concrete with low water absorption rate, high toughness and large doping amount of iron tailing sand

Abstract

The invention discloses a foam concrete formula with low water absorption rate, high toughness and large doping amount of iron tailing sand and a preparation method thereof. The formula is prepared from the following components in parts by mass: 180 to 588 parts of cement, 104 to 353 parts of iron tailing sand, 18 to 22 parts of foam, 0 to 7.28 parts of fiber and 223 to 333 parts of water. Wherein the foam is prepared by adding a surfactant and a foam stabilizing component into a vegetable protein foaming agent. The preparation method comprises the steps of dry and wet material mixing and pulping, foam preparation, slurry mixing and pouring maintenance. Through the synergistic effect of the fibers and the iron tailing sand and an optimized foaming system, while a large amount of iron tailing sand waste is effectively consumed, the water absorption rate of the foam concrete is remarkably reduced, the splitting tensile strength, the toughness and the anti-freezing durability are improved, and good economic benefits and environmental protection benefits are achieved.

Description

Technical Field

[0001] This invention belongs to the field of foamed concrete, specifically relating to a foamed concrete formula and preparation method of high-absorption, high-toughness iron tailings sand with low water absorption and high admixture content. Background Technology

[0002] Foamed concrete is a new type of environmentally friendly building material that uses cement, fly ash, and other cementing materials to introduce a large number of air bubbles through physical or chemical foaming methods, forming a lightweight and porous structure. Compared with ordinary concrete, it has advantages such as low density, high porosity, and controllable strength, and is widely used in civil engineering projects.

[0003] Iron tailings, a large amount of solid waste generated during iron ore beneficiation, are traditionally disposed of through stockpiling or landfilling. According to incomplete statistics, my country has accumulated billions of tons of iron tailings, with a comprehensive utilization rate of less than 10%, occupying vast amounts of land and causing serious environmental pollution. Meanwhile, low water absorption is a crucial performance indicator for foamed concrete, directly affecting its durability and frost resistance. Currently, many scholars utilize fly ash, mineral powder, and other waste materials to replace cement and natural sand in foamed concrete, improving its mechanical properties and reducing production costs. However, research on using iron tailings to prepare foamed concrete and achieving low water absorption is limited.

[0004] In summary, this invention aims to utilize iron tailings sand to prepare low-water-absorption, high-toughness foamed concrete, thereby solving environmental problems, improving the strength of foamed concrete, reducing production costs, and providing the construction industry with a high-performance green building material. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a low-water-absorption, high-toughness, high-volume iron tailings sand foamed concrete formula, characterized in that it comprises the following components by mass parts:

[0006] 180-588 parts cement;

[0007] 104-353 parts of iron tailings;

[0008] 18-22 parts foam;

[0009] Fiber content: 0-7.28 parts;

[0010] Water 223-333 portions.

[0011] Further, it is characterized by comprising the following components in parts by mass:

[0012] 312-445 parts cement;

[0013] 104-208 parts of iron tailings;

[0014] Foam 19-21 parts;

[0015] Fiber content: 3.64-7.28 parts;

[0016] Water 227-260 portions.

[0017] Further, the cement is characterized in that it is selected from one or a mixture of two of ordinary silicate cement and sulfoaluminate cement;

[0018] Preferably, when the cement is a mixture, the mass ratio of ordinary silicate cement to sulfoaluminate cement is 8:2 to 6:4.

[0019] Further, the iron tailings sand is characterized by having a fineness modulus of 0.5-1.5 and a particle size of less than 0.75 mm.

[0020] Furthermore, the fiber is characterized in that it is selected from one or a mixture of two of PVA fiber and basalt fiber;

[0021] When the fibers are a mixture, the mass ratio of PVA fibers to basalt fibers is 1:1.

[0022] Furthermore, the foam is characterized in that it is prepared from a foaming liquid using a foaming machine, the foaming liquid comprising a basic foaming agent, a surfactant, and a foam stabilizing component;

[0023] The basic foaming agent is a plant protein foaming agent;

[0024] The surfactants include sodium dodecyl sulfate and sodium dodecylbenzene sulfonate;

[0025] The foam-stabilizing component is polyacrylamide.

[0026] A method for preparing low-water-absorption, high-toughness, high-volume iron tailings sand foamed concrete as described in any of the above claims, characterized by comprising the following steps:

[0027] (1) Mix a certain proportion of iron tailings sand, fiber and cement, stir evenly, then add water and continue stirring to make cement slurry;

[0028] (2) Preparation of foam: The plant protein foaming agent is diluted to prepare a foaming liquid, and sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and polyacrylamide are added to the foaming liquid. Foam is then obtained using a foaming mechanism.

[0029] (3) Add the foam prepared in step (2) to the cement slurry in step (1), stir and mix evenly to obtain foamed concrete slurry;

[0030] (4) Pour the foamed concrete slurry into the mold, let it stand for curing, and then demold it to obtain the final product.

[0031] Furthermore, in step (1), the mixing time for dry materials is at least 1 minute, and the mixing time after adding water is at least 3 minutes.

[0032] Further, in step (2), the dilution ratio of the plant protein foaming agent is 1:40.

[0033] Furthermore, in step (4), oil is brushed on the inner wall of the mold before pouring, and plastic wrap is covered on top of the mold after pouring, with a standing time of 24 hours.

[0034] The beneficial effects of this invention are:

[0035] This invention effectively utilizes a large amount of iron tailings sand solid waste through specific raw material ratios and preparation processes, thereby reducing environmental pollution, saving land resources, and significantly lowering the production cost of foamed concrete.

[0036] This invention uses a plant protein foaming agent as a base, combined with sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and polyacrylamide to construct a composite foaming system. The foam generated by this system exhibits excellent stability and compatibility, and can remain stable in iron tailings mortar for a long time, promoting the formation of a large number of uniform and independent closed-cell structures inside the concrete. This significantly reduces the water absorption rate of the material and effectively improves the durability and freeze-thaw resistance of the concrete.

[0037] Furthermore, this invention introduces an appropriate amount of fiber component into the slurry, utilizing the strong bonding force generated between the fibers and the iron tailings sand mixture to improve the micromechanical properties of the matrix. This synergistic effect not only improves the splitting tensile strength of foamed concrete but also significantly enhances the material's crack resistance and toughness, overcoming the defects of ordinary foamed concrete's high brittleness and easy cracking, making it more suitable for complex engineering environments. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a flowchart illustrating the preparation process of low-water-absorption, high-toughness, high-volume iron tailings sand foamed concrete according to the present invention.

[0040] Figure 2 This is a picture of the actual product of the low water absorption, high toughness, and high-volume iron tailings sand foamed concrete of the present invention.

[0041] Figure 3 This is a flowability diagram of the low water absorption, high toughness, and high-volume iron tailings sand foamed concrete of the present invention. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to specific embodiments and comparative examples. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available industrial-grade products.

[0043] The present invention provides a low-water-absorption, high-toughness, high-volume iron tailings sand foamed concrete, the raw materials of which include cement, iron tailings sand, fiber, foam, and water. Wherein:

[0044] Ordinary Portland cement or sulfoaluminate cement, or a mixture of the two, can be used. When using mixed cement, the mass ratio of ordinary Portland cement to sulfoaluminate cement should be between 8:2 and 6:4. The fineness modulus of iron tailings sand should be controlled between 0.5 and 1.5, and the particle size should be less than 0.75 mm.

[0045] The fibers used are PVA fibers or basalt fibers, or a mixture of the two; when using a mixture, the mass ratio of PVA fibers to basalt fibers is 1:1. Specifically, the PVA fibers have a diameter of 0.039 mm, a length of 6 mm, an elongation at break of approximately 6%, an elastic modulus of 40 GPa, and a tensile strength of 1500 MPa. The basalt fibers have a diameter of 0.012 mm, a length of 6 mm, an elongation at break of approximately 3%, an elastic modulus of 105 GPa, and a tensile strength of 3700 MPa.

[0046] The foam is prepared from a foaming liquid using a foaming machine. The foaming liquid formulation includes a plant protein foaming agent as the base foaming agent, sodium dodecyl sulfate and sodium dodecylbenzene sulfonate as surfactants, and polyacrylamide as a foam stabilizing component. The dilution ratio of the plant protein foaming agent to water is 1:40. The prepared foam can achieve a foaming ratio of up to 40 times, a settling distance of 2.8 mm in 1 hour, and a water exudation of 29 mL in 1 hour.

[0047] The general preparation method of foamed concrete described in this invention is as follows: Figure 1 As shown, the details are as follows:

[0048] First, dry and wet materials are mixed. A certain amount of iron tailings sand, fiber and cement are thoroughly mixed in a mixing tank. The dry material is mixed for no less than 1 minute. Then, water is slowly added and the mixture is continuously mixed for no less than 3 minutes to make a uniform cement slurry.

[0049] To prepare foam, a plant protein foaming agent was diluted at a ratio of 1:40 to prepare a foaming liquid. Sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and polyacrylamide were added to the foaming liquid, and foam was obtained using a foaming mechanism.

[0050] Next, add the prepared foam to the cement slurry and continue stirring for 5 minutes to obtain foamed concrete slurry.

[0051] Finally, pouring and curing are carried out. The foamed concrete slurry is poured into the mold that has been brushed with oil beforehand, and a layer of plastic wrap is placed on top of the mold to prevent moisture loss and collapse. After curing for 24 hours, the mold is removed to obtain the iron tailings sand foamed concrete module.

[0052] Example 1:

[0053] A low-water-absorption, high-toughness, high-volume iron tailings sand foamed concrete is provided, the formulation of which includes: 416 parts ordinary Portland cement, 104 parts iron tailings sand, 7.28 parts fiber, 260 parts water, and 20 parts foam. The preparation process strictly follows the above-mentioned general preparation method.

[0054] Example 2:

[0055] Another type of low-water-absorption, high-toughness, high-volume iron tailings sand foamed concrete is provided, whose formula components include: 312 parts ordinary Portland cement, 208 parts iron tailings sand, 3.64 parts fiber, 260 parts water, and 20 parts foam. The preparation process strictly follows the above-mentioned general preparation method.

[0056] Example 3:

[0057] A reference foamed concrete is provided, the formulation of which includes: 416 parts ordinary Portland cement, 104 parts iron tailings sand, 3.64 parts fiber, 260 parts water, and 20 parts foam. The preparation process is strictly carried out according to the above-mentioned general preparation method.

[0058] Comparative Example 1:

[0059] A fiber-free foamed concrete is provided, the formulation of which includes: 416 parts ordinary Portland cement, 104 parts iron tailings sand, 0 parts fiber, 260 parts water, and 20 parts foam. The preparation process is the same as in Example 1, except that no fiber is added.

[0060] Comparative Example 2:

[0061] A conventional foamed concrete containing neither iron tailings sand nor fiber is provided. Its formulation comprises: 520 parts ordinary silicate cement, 0 parts iron tailings sand, 0 parts fiber, 260 parts water, and 20 parts foam. The preparation process is the same as in Example 3, except that no fiber is added.

[0062] To verify the technical effects of the present invention, performance tests were conducted on the foamed concrete prepared in Examples 1 to 3 and Comparative Examples 1 to 2. The tests included flowability, 7-day and 28-day compressive strength, flexural strength, water absorption, splitting tensile strength, and freeze-thaw cycle performance. Specific data obtained from the tests are shown in Table 1. Actual foamed concrete samples prepared in Examples 1 to 3 and Comparative Examples 1 to 2 are shown in Table 1. Figure 2 As shown in the figure, the actual flowability comparison is as follows: Figure 3 As shown.

[0063] Table 1 Summary of performance test results for examples and comparative examples

[0064]

[0065] From Table 1 and Figure 2 , Figure 3 The test results show that the foamed concrete prepared in Examples 1 to 3 of this invention all meet the requirements of JG / T 266-2011. Comparing the data of the examples and the comparative examples, it can be seen that this invention significantly reduces the water absorption rate of foamed concrete through the synergistic effect of iron tailings sand and fibers, with Example 2 showing the lowest water absorption rate at 19.8%. Simultaneously, this formulation significantly improves the splitting tensile strength, reaching 0.24 MPa in Example 2, far exceeding the 0.07 MPa of Comparative Example 2. This indicates that incorporating fibers into the slurry enhances the tensile strength and crack resistance of the concrete, while also improving its toughness. In the freeze-thaw cycle test, the strength loss rate and mass loss rate of Examples 1 and 2 were lower than those of the comparative example, indicating that the foamed concrete prepared by this invention has superior durability and freeze-thaw resistance. Example 2, even with the addition of 208 parts of iron tailings sand, still maintained excellent mechanical properties and extremely low water absorption, proving that the formulation of this invention can effectively absorb large amounts of iron tailings sand solid waste.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A foamed concrete formula for low water absorption, high toughness, and high iron tailings sand, characterized in that, Based on parts by mass, it includes the following components: 180-588 parts cement; 104-353 parts of iron tailings; 18-22 parts foam; Fiber content: 0-7.28 parts; Water 223-333 portions.

2. The low water absorption, high toughness, high-volume iron tailings sand foamed concrete formula according to claim 1, characterized in that, Based on parts by mass, it includes the following components: 312-445 parts cement; 104-208 parts of iron tailings; Foam 19-21 parts; Fiber content: 3.64-7.28 parts; Water 227-260 portions.

3. The low water absorption, high toughness, high-volume iron tailings sand foamed concrete formula according to claim 1, characterized in that, The cement is selected from one or a mixture of two of ordinary Portland cement and sulfoaluminate cement; Preferably, when the cement is a mixture, the mass ratio of ordinary silicate cement to sulfoaluminate cement is 8:2 to 6:

4.

4. The low water absorption, high toughness, high-volume iron tailings sand foamed concrete formula according to claim 1, characterized in that, The fineness modulus of the iron tailings sand is 0.5-1.5, and the particle size is less than 0.75 mm.

5. The low water absorption, high toughness, high-volume iron tailings sand foamed concrete formula according to claim 1, characterized in that, The fiber is selected from one or a mixture of two of PVA fiber and basalt fiber; When the fibers are a mixture, the mass ratio of PVA fibers to basalt fibers is 1:

1.

6. The low water absorption, high toughness, high-volume iron tailings sand foamed concrete formula according to claim 1, characterized in that, The foam is prepared from a foaming liquid using a foaming machine, and the foaming liquid includes a basic foaming agent, a surfactant, and a foam stabilizing component. The basic foaming agent is a plant protein foaming agent; The surfactants include sodium dodecyl sulfate and sodium dodecylbenzene sulfonate; The foam-stabilizing component is polyacrylamide.

7. A method for preparing low-water-absorption, high-toughness, high-volume iron tailings sand foamed concrete as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) Mix a certain proportion of iron tailings sand, fiber and cement, stir evenly, then add water and continue stirring to make cement slurry; (2) Preparation of foam: The plant protein foaming agent is diluted to prepare a foaming liquid, and sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and polyacrylamide are added to the foaming liquid. Foam is then obtained using a foaming mechanism. (3) Add the foam prepared in step (2) to the cement slurry in step (1), stir and mix evenly to obtain foamed concrete slurry; (4) Pour the foamed concrete slurry into the mold, let it stand for curing, and then demold it to obtain the final product.

8. The preparation method according to claim 7, characterized in that, In step (1), the mixing time for dry materials is at least 1 minute, and the mixing time after adding water is at least 3 minutes.

9. The preparation method according to claim 7, characterized in that, In step (2), the dilution ratio of the plant protein foaming agent is 1:

40.

10. The preparation method according to claim 7, characterized in that, In step (4), oil is brushed on the inner wall of the mold before pouring, and plastic wrap is covered on top of the mold after pouring, with a standing time of 24 hours.

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