A high-efficiency sound-absorbing lightweight aggregate foam concrete and its preparation method and application

Abstract

The invention discloses a highly efficient sound-absorbing lightweight aggregate foam concrete and a preparation method and application thereof, and belongs to the field of inorganic non-metallic materials. The highly efficient sound-absorbing lightweight aggregate foam concrete comprises: 85-95 parts by weight of sulphur-aluminium-iron low-carbon cementitious material, 5-15 parts by weight of auxiliary cementitious material, 0.6-1.5 parts by weight of functional admixture, 20-60 parts by weight of unburned lightweight aggregate, 0.35-0.45 parts by weight of water, and 0.5-1.5 L of prefabricated foam; the unburned lightweight aggregate comprises, by weight: 40-50 parts of sulphur-aluminium-iron low-carbon cementitious material, 50-60 parts of by-product gypsum, 0.7-1.5 parts of chemical foaming agent, 15-22 parts of water, and 5-8 parts of expanded perlite. The present invention achieves a relatively balanced wide-band sound absorption performance and adjustable sound absorption frequency range by constructing a multi-level multi-scale pore structure of expanded perlite pores + hydrogen peroxide foaming pores + physical foaming pores, and the sound absorption and noise reduction coefficient (NRC) of the material is ≥0.80 and the bulk density is ≤500 kg / m 3 , flexural strength ≥1.5 MPa.

Description

Technical Field

[0001] The invention belongs to the field of inorganic non-metallic materials, and specifically relates to a highly efficient sound-absorbing lightweight aggregate foam concrete and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] In the context of modern urbanization and the densification of transportation networks, noise pollution along highways, railways and subways has become increasingly prominent. Traffic noise in these areas is often persistent and has a wide impact, which not only affects the daily lives of residents along the lines, but also poses a potential threat to human health. More seriously, continuous traffic noise can lead to an increased risk of chronic diseases. Therefore, controlling noise pollution in these environments is crucial to the health and quality of life of urban residents.

[0004] The existing technical solutions mainly include mineral wool and glass fiber wool, polyurethane foam and foam concrete sound-absorbing panels. Foam concrete sound-absorbing panels are particularly suitable for complex outdoor environments because of their strong weather resistance, good fire resistance and durability, and easy construction and maintenance. However, the sound absorption coefficient of foam concrete is relatively limited, especially the low-frequency absorption performance. At the same time, the raw materials of foam concrete usually require cement and natural sand and gravel. The cement industry accounts for about 8% of the global anthropogenic CO2 emissions. Excessive exploitation of sand and gravel seriously threatens the stability of rivers and river ecosystems. In addition, traditional cement adhesives solidify slowly, which causes the instability of the pore structure of foam concrete and the long production process cycle. This is not conducive to its low-carbon sustainable development. Therefore, it is necessary to develop solid waste-based lightweight aggregate foam concrete with good sound absorption performance and adjustable sound absorption frequency range. Used on the walls of highways, railways and subways, it helps to effectively reduce the propagation and diffusion of noise, reduce the negative impact of noise sources on people, and thus improve the overall quality of the urban living environment from the source. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide a highly efficient sound-absorbing lightweight aggregate foam concrete and a preparation method and application thereof, by constructing a multi-level-multi-scale pore structure of expanded perlite pores-hydrogen peroxide foaming pores-physical foaming pores, so as to achieve a relatively balanced wide-band sound absorption performance of the material and an adjustable sound absorption frequency range, and the sound absorption noise reduction coefficient (NRC) of the highly efficient sound-absorbing lightweight aggregate foam concrete is ≥ 0.80, and the bulk density is ≤ 500 kg / m 3 , flexural strength ≥1.5 MPa.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] In a first aspect, the present invention provides a highly efficient sound-absorbing lightweight aggregate foam concrete, comprising: 85-95 parts by weight of a sulfur-aluminum-iron low-carbon cementitious material, 5-15 parts by weight of an auxiliary cementitious material, 0.6-1.5 parts by weight of a functional admixture, 20-60 parts by weight of a non-fired lightweight aggregate, 0.35-0.45 parts by weight of water, and 0.5-1.5 L of prefabricated foam;

[0008] The unburned lightweight aggregate comprises, by weight: 40-50 parts of sulfur-aluminum-iron low-carbon cementitious material, 50-60 parts of by-product gypsum, 0.7-1.5 parts of chemical foaming agent, 15-22 parts of water, and 5-8 parts of expanded perlite;

[0009] The high-efficiency sound-absorbing lightweight aggregate foam concrete has a sound absorption and noise reduction coefficient (NRC) of ≥ 0.80 and a bulk density of ≤ 500 kg / m 3 , flexural strength ≥ 1.5 MPa.

[0010] Preferably, 0.80≤sound absorption and noise reduction coefficient≤0.90, 200kg / m 3 ≤Bulk weight≤500kg / m 3 .

[0011] The high-efficiency sound-absorbing lightweight aggregate foam concrete constructs a multi-level and multi-scale pore structure of expanded perlite pores-hydrogen peroxide foaming pores-physical foaming pores, wherein the expanded perlite is used as the primary pore with a pore size of 20-200 μm, the hydrogen peroxide foaming is further used as the secondary pore with a pore size of ≤20 μm, and the physical foaming is further used as the multi-level pore with a pore size of 200-1500 μm.

[0012] In one or more embodiments, the ferro-aluminum-sulfur low-carbon cementitious material comprises CaO≥37%, Al2O3≥20%, Fe2O3≥6%, and SO3≥8%; the auxiliary cementitious material comprises slag, fly ash or silica ash, and the fineness and specific surface area thereof are not less than 350 m² / kg.

[0013] In one or more embodiments, the functional admixture includes, by weight: 0.2-0.6 parts of water reducer, 0.1-0.3 parts of thickener, and 0.3-0.6 parts of chopped fibers.

[0014] Furthermore, the water reducer is a polycarboxylate water reducer; the thickener is selected from one or more of hydroxypropyl methyl cellulose ether, starch and polyacrylamide; the chopped fibers are selected from one or more of polypropylene fibers, polyvinyl alcohol fibers and glass fibers, and the length of the chopped fibers is 3 mm-12 mm.

[0015] In one or more embodiments, the by-product gypsum is desulfurized gypsum, phosphogypsum or fluorinated gypsum, wherein the content of dihydrate gypsum is greater than 90% and the average particle size is ≤50 μm.

[0016] In one or more embodiments, the chemical foaming agent is hydrogen peroxide with a mass concentration of 30-50%.

[0017] In one or more embodiments, the bulk density of the expanded perlite is: 100-130 kg / m 3 .

[0018] In one or more embodiments, the prefabricated foam includes a foaming agent, water and a foam stabilizer, the dilution ratio of the foaming agent to water is 1:(20-45), and the foam stabilizer accounts for 2%-5% of the mass of the foaming agent.

[0019] Furthermore, the foaming agent is a rosin resin foaming agent, a synthetic surfactant foaming agent, a protein foaming agent or a composite foaming agent.

[0020] Furthermore, the foam stabilizer is selected from one or more of xanthan gum, silica sol and polyvinyl alcohol.

[0021] In a second aspect, the present invention provides a method for preparing the above-mentioned high-efficiency sound-absorbing lightweight aggregate foam concrete, comprising the following steps:

[0022] Step 1: Stir the sulphur-aluminium-iron low-carbon cementitious material, auxiliary cementitious material, functional admixture and water to form a uniform mixed slurry;

[0023] Step 2: Add the pre-wetted unburned lightweight aggregate to the uniformly mixed slurry and continue stirring;

[0024] Step 3: Add prefabricated foam and stir until there is no white foam, then pour it into the mold to solidify. It can be demoulded after 6-8 hours to complete the preparation of high-efficiency sound-absorbing lightweight aggregate foam concrete.

[0025] In one or more embodiments, in step 1, the stirring time is 3-5 min; the speed during stirring is 40-60 r / min.

[0026] In step 2, the stirring speed is 25-35 r / min, and the stirring time is 1-3 min.

[0027] In one or more embodiments, the method for preparing the unfired lightweight aggregate is: a sulfide-aluminum-iron low-carbon cementitious material and a by-product gypsum dry material are evenly mixed to form a mixture; expanded perlite is used as a masterbatch, and in a granulator, the preparation of the unfired lightweight aggregate is completed by spraying the mixture while spraying a mixture of a chemical foaming agent and water.

[0028] In one or more embodiments, in step three, the method for preparing the prefabricated foam is: dilute the foaming agent and water in a ratio of 1: (20-45), add a foam stabilizer accounting for 2%-5% of the mass of the foaming agent, and stir evenly to form a foaming liquid; take the foaming liquid and place it in a foaming machine to prepare the prefabricated foam.

[0029] In a third aspect, the present invention provides the application of the above-mentioned high-efficiency sound-absorbing lightweight aggregate foam concrete in sound insulation and noise reduction in the fields of construction and transportation.

[0030] One or some of the above technical solutions have the following advantages or beneficial effects:

[0031] (1) The present invention provides a highly efficient sound-absorbing lightweight aggregate foam concrete. By constructing a multi-level open-pore structure of expanded perlite pores, hydrogen peroxide foaming pores, and physical foaming pores, the pore structure of the material is enriched, and the sound absorption performance of the material is greatly improved. The low-frequency sound absorption is significantly enhanced, and the high-frequency sound absorption is steadily improved. The material has a relatively balanced wide-band sound absorption performance and the sound absorption frequency range (50-6500 HZ) is adjustable. The NRC of the material is greater than 0.80, and the bulk density is ≤ 500kg / m 3 , flexural strength ≥ 1.5 MPa.

[0032] (2) The present invention solves the problem that low-grade solid waste is difficult to utilize. In the preparation process of high-efficiency sound-absorbing lightweight aggregate foam concrete, the synergistic stimulation and cascade utilization of solid waste are achieved, which greatly improves the comprehensive utilization rate of solid waste, and at the same time ensures the excellent mechanical properties of the material, with good compatibility and strength performance. Among them, synergistic stimulation means that calcium sulfate in the by-product gypsum will participate in and promote the hydration of calcium sulfoaluminate in the sulfoaluminum-iron low-carbon cementitious materials, and jointly form calcium sulfaluminate and aluminum gel. The alkalinity of the cementitious material and the calcium sulfate in the phosphogypsum jointly stimulate the dissolution of active silicon and aluminum in the auxiliary cementitious materials, and further synergistically synthesize new calcium sulfaluminate and CSH gel, etc. The synergistic stimulation between them jointly promotes the formation of hydration products and performance improvement. Cascade utilization means that not only a large amount of solid waste is introduced in the preparation process of the sulfoaluminum-iron low-carbon cementitious materials, but also auxiliary cementitious materials, by-product gypsum and other solid wastes can be further compounded during the use of the sulfoaluminum-iron low-carbon cementitious materials, thereby realizing multi-level utilization of solid waste.

[0033] (3) The entire preparation process combines the fast-hardening and early-strengthening characteristics of the sulfur-aluminum-iron low-carbon cementitious material, which can achieve the early hardening speed of the sound-absorbing material and the solidification of the foam structure at an early stage, thereby improving the stability of the foam matrix. In terms of process, the steaming and curing steps are eliminated, the process energy consumption is reduced, and the demolding time of the product is greatly shortened, thereby improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0035] Figure 1 The process flow chart in the embodiment of the present invention is shown;

[0036] Figure 2 This is a diagram of the internal pores of the highly efficient sound-absorbing lightweight aggregate foam concrete prepared in Example 1 of the present invention; wherein the magnification is 20 times;

[0037] Figure 3 The sound absorption performance of the high-efficiency sound-absorbing lightweight aggregate foam concrete prepared in Example 1 of the present invention is compared with that of the conventional foam concrete prepared in Comparative Example 1. DETAILED DESCRIPTION

[0038] In order to solve the following technical problems existing in the prior art: (1) the sound absorption performance of traditional foamed concrete is poor, especially the low-frequency sound absorption performance; (2) it is difficult to ensure the stability of the pore structure of traditional foamed concrete, and the pore structure is single; (3) the carbon emission and energy consumption of traditional foamed concrete are higher, the production cycle is longer, and it is not conducive to sustainable development. The present invention provides a high-efficiency sound-absorbing light aggregate foamed concrete and a preparation method thereof, wherein a sulphur-aluminum-iron series low-carbon cementitious material and by-product gypsum are used as composite adhesives, hydrogen peroxide is used as a foaming agent, and expanded perlite is used as a masterbatch to synthesize an unburned light aggregate in a granulator; then a sulphur-aluminum-iron series low-carbon cementitious material and an auxiliary cementitious material are used as adhesives, self-made unburned light aggregate is used as aggregate, a water reducer, a thickener and short-cut fibers are used as functional admixtures, and water and prefabricated foams are added to finally synthesize an unburned light aggregate foamed concrete with good sound absorption performance, adjustable sound absorption frequency range, and low carbon sustainability.

[0039] The lightweight aggregate foam concrete can greatly improve the sound absorption performance of the material, achieve relatively balanced broadband sound absorption performance and adjustable sound absorption frequency range; enrich the pore structure of the material and ensure the good compatibility and strength performance of the material; solve the problem of low-grade solid waste being difficult to utilize and realize the multi-level utilization of solid waste; improve the early hardening speed of the sound-absorbing material and shorten the production cycle of the product.

[0040] Compared with the existing technology, the high-efficiency sound-absorbing lightweight aggregate foam concrete prepared by the present invention has excellent sound absorption performance, realizes relatively balanced broadband sound absorption performance and adjustable sound absorption frequency range. The main technical means are as follows:

[0041] (1) By introducing expanded perlite to enrich the internal open pore structure, primary open pores are formed with a pore size of 20-200 μm.

[0042] (2) The expanded perlite was surface modified to strengthen its bonding with the cementitious system. At the same time, hydrogen peroxide was used for in-situ foaming to introduce pores into its surface shell layer and construct open secondary pores with a pore size of ≤20 μm. Among them, the expanded perlite is a single open-pore structure. In order to further enrich its pores and enhance its bonding in the cementitious slurry, the expanded perlite was coated and modified, that is, a core-shell structure was formed on its surface using a sulfur-aluminum-iron low-carbon cementitious material + by-product gypsum. Of course, in order to ensure the porosity of the core-shell structure, chemical foaming was introduced, and finally a porous structure of unburned lightweight aggregate was prepared.

[0043] (3) A porous matrix is ​​further formed through physical foaming. In addition, the introduction of unburned lightweight aggregate during the mixing process will also increase the proportion of open pores in the matrix, with a pore size of 200-1500 μm. Ultimately, the construction of multi-level and multi-scale open pores is achieved. Among them, multi-level pores refer to the structure, including the selected expanded perlite, chemical foaming during the core-shell coating process, and the physical foaming pores of the gel slurry itself, so it is called multi-level pores. Multi-scale pores refer to the inclusion of nanopores, micron pores and millimeter pores achieved by the above method.

[0044] It should be noted that the chemical foaming in the present invention is mainly used to modify the expanded perlite. By coating and modifying the outer layer of the expanded perlite + chemical foaming, a lightweight aggregate is finally prepared, which enriches its nano-open pore structure and improves its strength; while the physical foaming is mainly used to introduce millimeter pores in the cementitious slurry.

[0045] During the entire preparation process, low-grade industrial solid waste is utilized in a cascade manner, greatly improving the comprehensive utilization rate of solid waste. Taking phosphogypsum as an example, it is not only used as one of the raw materials for sulfoaluminum-iron cementitious materials, but also used to modify expanded perlite and prepare foamed concrete. The sulfoaluminum-iron cementitious materials used are self-developed products with the characteristics of early strength, high strength, fast hardening, and corrosion resistance. Since the raw materials are almost all taken from industrial solid waste, and the firing temperature is about 300°C lower than that of ordinary Portland cement clinker, the energy consumption is lower, and it belongs to a low-carbon cementitious system. Using it to prepare foamed concrete can greatly improve the early performance of the material, thereby eliminating the process steps such as steaming, reducing the process energy consumption, and greatly shortening the demoulding time of the product, thereby improving production efficiency. Therefore, the present invention uses a large amount of industrial solid waste as raw materials to prepare lightweight aggregate foamed concrete with good sound absorption performance, adjustable sound absorption frequency range, and low carbon sustainability.

[0046] In a typical embodiment, the present invention provides a highly efficient sound-absorbing lightweight aggregate foam concrete, the raw materials of which include: 85-95 parts by weight of sulphur-aluminium-iron low-carbon cementitious material, 5-15 parts by weight of auxiliary cementitious material, 0.6-1.5 parts by weight of functional admixture, 20-60 parts by weight of unburned lightweight aggregate, 0.35-0.45 parts by weight of water, and 0.5-1.5 L of prefabricated foam;

[0047] The unburned lightweight aggregate comprises, by weight, 40-50 parts of sulfide-aluminum-iron low-carbon cementitious material, 50-60 parts of by-product gypsum, 0.7-1.5 parts of chemical foaming agent, 15-22 parts of water, and 5-8 parts of expanded perlite;

[0048] The high-efficiency sound-absorbing lightweight aggregate foam concrete has a sound absorption and noise reduction coefficient (NRC) of ≥ 0.80 and a bulk density of ≤ 500kg / m 3 , flexural strength ≥ 1.5 MPa. Preferably, 0.80≤NRC≤0.90, 200 kg / m 3 ≤Bulk weight≤500 kg / m 3 .

[0049] Among them, the noise reduction coefficient (NRC) of foam concrete is the average of four sound absorption coefficients at frequencies of 250 Hz, 500 Hz, 1000 Hz and 2000 Hz.

[0050] In one or more embodiments, the ferro-aluminum-sulfur low-carbon cementitious material has CaO≥37%, Al2O3≥20%, Fe2O3≥6%, and SO3≥8%, and is made by grinding 80% of clinker, 15% of by-product gypsum, and 5% of limestone powder. The preparation method is as follows: the clinker is a cementitious material with anhydrous calcium sulfoaluminate, Fe-Al soluble calcium sulfoaluminate, dicalcium silicate, iron phase, and anhydrous calcium sulfate as main mineral components, which is obtained by calcining at 1150-1250°C with solid waste containing silicon-aluminum-iron compounds and calcium sulfate as main raw materials.

[0051] In one or more embodiments, the auxiliary cementitious material includes slag, fly ash or silica fume, and the fineness and specific surface area are not less than 350 m² / kg.

[0052] In one or more embodiments, the functional admixture includes, by weight: 0.2-0.6 parts of water reducer, 0.1-0.3 parts of thickener, and 0.3-0.6 parts of chopped fibers.

[0053] Furthermore, the water reducing agent is a polycarboxylic acid water reducing agent, and the water reducing efficiency is 18-30%.

[0054] Furthermore, the thickener is hydroxypropyl methylcellulose ether, starch, polyacrylamide, etc.

[0055] Furthermore, the chopped fibers are one or more of polypropylene fibers, polyvinyl alcohol fibers and glass fibers, and the length of the chopped fibers is 3 mm-12 mm.

[0056] In one or more embodiments, the prefabricated foam includes a foaming agent, water and a foam stabilizer. The foaming agent is a rosin resin foaming agent, a synthetic surfactant foaming agent, a protein foaming agent and a composite foaming agent, etc., and the foam stabilizer is xanthan gum, silica sol, polyvinyl alcohol, etc. The dilution ratio of the foaming agent to water is 1: (20-45), and the foam stabilizer accounts for 2%-5% of the mass of the foaming agent.

[0057] In one or more embodiments, the by-product gypsum is original desulfurized gypsum, phosphogypsum or fluorinated gypsum, etc., and its main function is to provide calcium sulfate required for system hydration. Its dihydrate gypsum content is greater than 90%, and the average particle size is ≤50 um.

[0058] In one or more embodiments, the chemical foaming agent is hydrogen peroxide with a mass concentration of 30%-50%. Hydrogen peroxide and water are mixed to form a chemical foaming agent mixture, wherein the chemical foaming agent is 0.7-1.5 parts and water is 15-22 parts. No foaming catalyst is required during the chemical foaming process. This is because the Fe content in the above-mentioned ferrous-aluminum-based low-carbon cementitious material is increased. 3+ It can also catalyze the decomposition of hydrogen peroxide.

[0059] In one or more embodiments, the bulk density of the expanded perlite is 100-130 kg / m 3 .

[0060] In another typical embodiment, the present invention provides a method for preparing the above-mentioned high-efficiency sound-absorbing lightweight aggregate foam concrete, comprising the following steps:

[0061] Step 1: Stir the sulphur-aluminium-iron low-carbon cementitious material, auxiliary cementitious material, functional admixture and water to form a uniform mixed slurry;

[0062] Step 2: Add the pre-wetted unburned lightweight aggregate to the uniformly mixed slurry and continue stirring;

[0063] Step 3: Add prefabricated foam and stir until there is no white foam, then pour it into the mold to solidify. It can be demoulded after 6-8 hours to complete the preparation of high-efficiency sound-absorbing lightweight aggregate foam concrete.

[0064] In one or more embodiments, in step 1, the stirring time is 3-5 min; the speed during stirring is 40-60 r / min.

[0065] In one or more embodiments, in step 2, the rotation speed during stirring is 25-35 r / min, and the stirring time is 1-3 min.

[0066] In one or more embodiments, in step 2, the method for preparing the unfired lightweight aggregate is: a sulfide-aluminum-iron low-carbon cementitious material and a by-product gypsum dry material are evenly mixed to form a mixture; expanded perlite is used as a masterbatch, and the preparation of the unfired lightweight aggregate is completed in a granulator by spraying the mixture while spraying a mixture of a chemical foaming agent and water.

[0067] The chemical foaming agent mixed liquid is a mixed liquid of hydrogen peroxide and water.

[0068] In one or more embodiments, in step 2, the pre-wetted unburned light aggregate refers to soaking a certain mass of dry unburned light aggregate in water for 20-60 min, and then leaving it on the sieve for 5-15 min until no water drops fall from the unburned light aggregate. The purpose of this step is to avoid absorbing water in the mixed slurry when the dry unburned light aggregate is directly added to the mixed slurry.

[0069] In one or more embodiments, in step three, the prefabricated foam includes a foaming agent, water and a foam stabilizer. The foaming agent is a rosin resin foaming agent, a synthetic surfactant foaming agent, a protein foaming agent or a composite foaming agent; the foam stabilizer is selected from one or more of xanthan gum, silica sol and polyvinyl alcohol. The specific preparation method is: dilute the foaming agent and water in a ratio of 1: (20-45), add 2-5% of the mass of the foaming agent to the foaming agent, stir evenly to form a foaming liquid, and set aside; take the foaming liquid and place it in a physical foaming machine, the foaming pressure is 0.5 MPa, the water pump frequency is 70-90%, and the prefabricated foam is prepared.

[0070] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0071] Example 1

[0072] The present invention proposes a highly efficient sound-absorbing lightweight aggregate foam concrete and a preparation method thereof, comprising the following steps:

[0073] (1) Take 40 parts of ferro-aluminum low-carbon cementitious material and 60 parts of phosphogypsum, mix the dry materials evenly to form a mixture, and set aside;

[0074] (2) Weigh 1.5 parts of hydrogen peroxide and dissolve it in 22 parts of water to make a mixed solution for later use;

[0075] (3) Take bulk density of 100kg / m 38 parts of expanded perlite are used as masterbatch, and granulated in a granulator. The mixture (1) and the mixed liquid (2) are sprayed at the same time to complete the preparation of the unburned lightweight aggregate.

[0076] (4) Take 85 parts of ferro-aluminum low-carbon cementitious material, 15 parts of slag, 0.6 parts of polycarboxylate water reducer, 0.3 parts of hydroxypropyl methylcellulose ether, 0.6 parts of short-cut fiber, and 0.35 parts of water, stir at 50±5 r / min for 3 min to prepare a mixed slurry for later use;

[0077] (5) Take 20 parts of the unburned lightweight aggregate in (3), pre-wet it, let it stand, and then add it to the mixed slurry in (4). Use a horizontal mixer to stir at a speed of 30±5 r / min for 2 min and set aside.

[0078] (6) Dilute the foaming agent and water in a ratio of 1:30, add xanthan gum accounting for 2% of the mass of the foaming agent, stir evenly to make a foaming liquid, and set aside;

[0079] (7) Take the foaming liquid in (6) and place it in a cement foaming machine with a foaming pressure of 0.5 MPa and a water pump frequency of 80% to prepare prefabricated foam for standby use;

[0080] (8) Add 1.4 L of the prefabricated foam in (7) into (5), stir until there is no white foam, pour it into a mold and solidify it. It can be demoulded after 8 hours, thus completing the preparation of high-efficiency sound-absorbing lightweight aggregate foam concrete.

[0081] NRC coefficient 0.83, bulk density 350 kg / m 3 , flexural strength 1.5 MPa.

[0082] Figure 2 This is an internal pore diagram of the highly effective sound-absorbing lightweight aggregate foam concrete prepared in Example 1 of the present invention; wherein, the magnification is 20 times, and the multi-level and multi-scale open pore structure of the lightweight aggregate foam concrete prepared in the present invention can be clearly observed.

[0083] Example 2

[0084] The present invention proposes a highly efficient sound-absorbing lightweight aggregate foam concrete and a preparation method thereof, comprising the following steps:

[0085] (1) Take 45 parts of sulfur-aluminum-iron low-carbon cementitious material and 55 parts of desulfurized gypsum, mix the dry materials evenly to form a mixture, and set aside;

[0086] (2) Weigh 1.1 parts of hydrogen peroxide and dissolve it in 19 parts of water to make a mixed solution for later use;

[0087] (3) Take bulk density of 110kg / m 36.5 parts of expanded perlite is used as a master batch, and the mixture (1) and the mixed liquid (2) are sprayed in a granulator to prepare the unburned lightweight aggregate;

[0088] (4) Take 90 parts of ferro-aluminum low-carbon cementitious material, 10 parts of fly ash, 0.4 parts of polycarboxylate water reducer, 0.2 parts of hydroxypropyl methyl cellulose ether, 0.45 parts of short-cut fibers, and 0.40 parts of water, stir at 50±5 r / min for 3 min to prepare a mixed slurry for later use;

[0089] (5) Take 40 parts of the unburned lightweight aggregate in (3), pre-wet it and let it stand, add it to the mixed slurry in (4), stir at 30±5 r / min for 1 min, and set aside;

[0090] (6) Dilute the foaming agent and water in a ratio of 1:30, add xanthan gum accounting for 3% of the mass of the foaming agent, stir evenly to make a foaming liquid, and set aside;

[0091] (7) Take the foaming liquid in (6) and place it in a cement foaming machine with a foaming pressure of 0.5 MPa and a water pump frequency of 85% to prepare prefabricated foam for standby use;

[0092] (8) Add 1.1 L of the prefabricated foam in (7) into (5), stir until there is no white foam, pour it into a mold and solidify it. It can be demoulded after 7 hours, thus completing the preparation of high-efficiency sound-absorbing lightweight aggregate foam concrete.

[0093] NRC coefficient 0.81, bulk density 420 kg / m 3 , flexural strength 1.7 MPa.

[0094] Example 3

[0095] The present invention proposes a highly efficient sound-absorbing lightweight aggregate foam concrete and a preparation method thereof, comprising the following steps:

[0096] (1) Take 50 parts of ferro-aluminum low-carbon cementitious material and 50 parts of fluorgypsum, mix the dry materials evenly to make a mixture, and set aside;

[0097] (2) Weigh 0.8 parts of hydrogen peroxide and dissolve it in 16 parts of water to make a mixed solution for later use;

[0098] (3) Take bulk density of 130kg / m 3 5 parts of expanded perlite are used as masterbatch, and granulated in a granulator. The mixture (1) and the mixed liquid (2) are sprayed at the same time to complete the preparation of the unburned lightweight aggregate.

[0099] (4) Take 95 parts of ferro-aluminum low-carbon cementitious material, 5 parts of silica fume, 0.2 parts of polycarboxylic acid water reducer, 0.1 parts of hydroxypropyl methyl cellulose ether, 0.3 parts of short-cut fiber, and 0.45 parts of water, stir at 50±5 r / min for 3 min to prepare a mixed slurry for later use;

[0100] (5) Take 60 parts of the unburned lightweight aggregate in (3), pre-wet it and let it stand, add it to the mixed slurry in (4), stir at 30±5 r / min for 1 min, and set aside;

[0101] (6) Dilute the foaming agent and water in a ratio of 1:30, add xanthan gum accounting for 5% of the mass of the foaming agent, stir evenly to make a foaming liquid, and set aside;

[0102] (7) Take the foaming liquid in (6) and place it in a cement foaming machine with a foaming pressure of 0.5 MPa and a water pump frequency of 90% to prepare prefabricated foam for standby use;

[0103] (8) Add 0.8 L of the prefabricated foam in (7) into (5), stir until there is no white foam, pour it into a mold and solidify it. It can be demoulded after 6 hours, thus completing the preparation of high-efficiency sound-absorbing lightweight aggregate foam concrete.

[0104] NRC coefficient 0.80, bulk density 500 kg / m 3 , flexural strength 1.8 MPa.

[0105] Comparative Example 1

[0106] Different from Example 1, steps 1, 2, 3, and 5 are omitted, and the foamed concrete prepared by only steps 4, 6, 7, and 8, that is, the addition of unburned lightweight aggregate is omitted, which is "conventional foamed concrete".

[0107] NRC coefficient 0.45, bulk density 710 kg / m 3 , flexural strength 2.5 MPa.

[0108] Comparative Example 2

[0109] Different from Example 1, steps 6 and 7 are omitted, that is, the final physical foaming is not added, and only a multi-level and multi-scale pore structure of expanded perlite pores and hydrogen peroxide foaming pores is prepared.

[0110] NRC coefficient 0.26, bulk density 1060 kg / m 3 , flexural strength 3.0 MPa.

[0111] Comparative Example 3

[0112] Different from Example 1, no expanded perlite is added in step 3.

[0113] NRC coefficient 0.44, bulk density 760 kg / m 3 , flexural strength 2.6 MPa.

[0114] Table 1 High performance and high efficiency sound absorption lightweight aggregate foam concrete

[0115]

[0116] As can be seen from Table 1, the sound absorption performance of the highly efficient sound-absorbing lightweight aggregate foamed concrete of the present invention is greatly improved by coupling the expanded perlite modified by chemical foaming + core-shell coating with physical foaming, and the high-frequency sound absorption coefficient can reach above 0.9; in addition, we can achieve a more balanced wide-band sound absorption performance of the material and an adjustable sound absorption frequency range by adjusting the particle size and mixing ratio of the unburned lightweight aggregate, the degree of chemical foaming and physical foaming, and other technical means. It can be seen that the sound-absorbing lightweight aggregate foamed concrete prepared by the present invention is a highly efficient sound-absorbing material with excellent sound absorption performance, a wide sound absorption frequency range, and low carbon sustainability.

[0117] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A highly efficient sound-absorbing lightweight aggregate foam concrete, characterized in that: include: 85-95 parts by weight of ferro-aluminum low-carbon cementitious material, 5-15 parts by weight of auxiliary cementitious material, 0.6-1.5 parts by weight of functional admixture, 20-60 parts by weight of unburned lightweight aggregate, 0.35-0.45 parts by weight of water, and 0.5-1.5 L of prefabricated foam; The unburned lightweight aggregate comprises, by weight: 40-50 parts of sulfide-aluminum-iron low-carbon cementitious material, 50-60 parts of by-product gypsum, 0.7-1.5 parts of chemical foaming agent, 15-22 parts of water, and 5-8 parts of expanded perlite; The high-efficiency sound-absorbing lightweight aggregate foam concrete has a sound absorption and noise reduction coefficient of ≥0.80 and a bulk density of ≤500 kg / m 3 ; The functional admixture includes, by weight: 0.2-0.6 parts of water reducing agent, 0.1-0.3 parts of thickener, and 0.3-0.6 parts of chopped fiber; The high-efficiency sound-absorbing lightweight aggregate foam concrete constructs a multi-level and multi-scale pore structure of expanded perlite pores, hydrogen peroxide foaming pores, and physical foaming pores; The auxiliary cementitious material includes slag, fly ash or silica fume; The method for preparing the highly efficient sound-absorbing lightweight aggregate foam concrete comprises the following steps: Step 1: Stir the sulphur-aluminium-iron low-carbon cementitious material, auxiliary cementitious material, functional admixture and water to form a uniform mixed slurry; Step 2: Add the pre-wetted unburned lightweight aggregate to the uniformly mixed slurry and continue stirring; Step 3: Add prefabricated foam and stir until there is no white foam, then pour it into the mold for solidification, and demould after 6-8 hours to complete the preparation of high-efficiency sound-absorbing lightweight aggregate foam concrete; In step 2, the method for preparing the unburned lightweight aggregate is: a sulphur-aluminium-iron low-carbon cementitious material and a by-product gypsum dry material are uniformly mixed to form a mixture; expanded perlite is used as a masterbatch, and in a granulator, the preparation of the unburned lightweight aggregate is completed by spraying the mixture while spraying a mixture of a chemical foaming agent and water.

2. The high-efficiency sound-absorbing lightweight aggregate foam concrete according to claim 1, characterized in that: 0.80≤Sound absorption and noise reduction coefficient≤0.90, 200kg / m 3 ≤Bulk weight≤500kg / m 3 ; The sulphur-aluminum-iron low-carbon cementitious material contains CaO≥37%, Al2O3≥20%, Fe2O3≥6%, and SO3≥8%; The auxiliary cementitious material has a fineness specific surface area of ​​not less than 350 m² / kg.

3. The high-efficiency sound-absorbing lightweight aggregate foam concrete according to claim 1, characterized in that: The water reducer is a polycarboxylate water reducer; The thickener is selected from one or more of hydroxypropyl methylcellulose ether, starch and polyacrylamide; The chopped fibers are selected from one or more of polypropylene fibers, polyvinyl alcohol fibers and glass fibers, and the length of the chopped fibers is 3 mm to 12 mm.

4. The high-efficiency sound-absorbing lightweight aggregate foam concrete according to claim 1, characterized in that: The by-product gypsum is desulfurized gypsum, phosphogypsum or fluorinated gypsum, wherein the content of dihydrate gypsum is greater than 90% and the average particle size is ≤50 μm; The chemical foaming agent is hydrogen peroxide with a mass concentration of 30-50%; The bulk density of the expanded perlite is 100-130 kg / m 3 .

5. The high-efficiency sound-absorbing lightweight aggregate foam concrete according to claim 1, characterized in that: The prefabricated foam comprises a foaming agent, water and a foam stabilizer, the dilution ratio of the foaming agent to water is 1:(20-45), and the foam stabilizer accounts for 2%-5% of the mass of the foaming agent; The foaming agent is a rosin resin foaming agent, a synthetic surfactant foaming agent, a protein foaming agent or a composite foaming agent; The foam stabilizer is selected from one or more of xanthan gum, silica sol and polyvinyl alcohol.

6. The method for preparing high-efficiency sound-absorbing lightweight aggregate foam concrete according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: Stir the sulphur-aluminium-iron low-carbon cementitious material, auxiliary cementitious material, functional admixture and water to form a uniform mixed slurry; Step 2: Add the pre-wetted unburned lightweight aggregate to the uniformly mixed slurry and continue stirring; Step 3: Add prefabricated foam and stir until there is no white foam, then pour it into the mold for solidification, and demould after 6-8 hours to complete the preparation of high-efficiency sound-absorbing lightweight aggregate foam concrete; In step 2, the method for preparing the unburned lightweight aggregate is: a sulphur-aluminium-iron low-carbon cementitious material and a by-product gypsum dry material are uniformly mixed to form a mixture; expanded perlite is used as a masterbatch, and in a granulator, the preparation of the unburned lightweight aggregate is completed by spraying the mixture while spraying a mixture of a chemical foaming agent and water.

7. The preparation method according to claim 6, characterized in that: In step 1, the stirring time is 3-5 minutes; the speed during stirring is 40-60 r / min; In step 2, the stirring speed is 25-35 r / min, and the stirring time is 1-3 min.

8. The preparation method according to claim 6, characterized in that: In step three, the preparation method of the prefabricated foam is: dilute the foaming agent and water in a ratio of 1: (20-45), add a foam stabilizer accounting for 2%-5% of the mass of the foaming agent, and stir evenly to form a foaming liquid; take the foaming liquid and place it in a foaming machine to prepare the prefabricated foam.

9. Use of the high-efficiency sound-absorbing lightweight aggregate foamed concrete according to any one of claims 1 to 5 or the high-efficiency sound-absorbing lightweight aggregate foamed concrete obtained by the preparation method according to any one of claims 6 to 8 in sound insulation and noise reduction in the fields of construction and transportation.

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