Self-thermal-insulation building material based on cement-fly ash waste and preparation method of self-thermal-insulation building material

Abstract

The invention provides a cement-fly ash waste-based self-insulation building material, which is prepared from the following ingredients in parts by weight: 60 to 80 parts of fly ash, 20 to 30 parts of cement, 10 to 20 parts of slag powder, 1 to 8 parts of silica fume, 3 to 10 parts of ardealite and 10 to 15 parts of expanded perlite. The foaming agent, the accelerator, the polycarboxylic acid water reducing agent and the straw particles are sequentially arranged from top to bottom, and the water-cement ratio is 0.45-0.55. The foaming agent, the accelerator, the polycarboxylic acid water reducing agent and the straw particles are sequentially arranged from top to bottom. According to the invention, the expanded perlite is modified, and the composite foaming agent is adopted, so that the green self-insulation building material with good performance is prepared. According to the self-insulation building material disclosed by the invention, the fly ash and the slag are used as main cementing materials, so that the reutilization of solid wastes such as the fly ash and the like is realized, the environmental pollution is reduced, the production cost of the building material is reduced, and the strength of the material can be enhanced while the heat conductivity coefficient and the quality of the material are reduced; the wall insulation requirement is met, and the energy-saving and environment-friendly effects are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of thermal insulation building materials, and in particular to a self-thermal insulation building material based on cement-fly ash waste and a preparation method thereof. Background Art

[0002] In my country's northern coal-fired power generation areas, the output of fly ash is large, but the disposal capacity is limited, and the utilization rate of fly ash is very low. The rest is disposed of by landfill and other methods, causing serious damage to the soil, groundwater, and atmospheric environment. Fly ash is fine ash collected from the flue gas after coal combustion, and is the main solid waste discharged by coal-fired power plants. With the development of the electric power industry, the amount of fly ash discharged from coal-fired power plants has increased year by year, becoming one of the largest industrial waste residues in my country. With people's increasing attention to the utilization of fly ash resources, how to develop new green and environmentally friendly products based on the characteristics of fly ash has become an important research direction for the high-value development and utilization of fly ash.

[0003] As a new type of building energy-saving material that is lightweight, heat-insulating, sound-insulating, earthquake-resistant and fire-resistant, foamed concrete is widely used in engineering fields such as wall insulation, lightweight panels, and fire-resistant core doors. Foamed concrete is a material containing a large number of closed pores that is made by mechanically making a foaming agent (aqueous solution) into foam, and then mixing the foam into a mixture of siliceous materials (sand, fly ash), calcium materials (cement, lime), various admixtures and water, and then mixing, pouring, and curing. Because foamed concrete contains a large number of pores, it has good thermal insulation properties and is a high-quality thermal insulation building material.

[0004] The inventor has long been committed to the research of self-insulating building materials. The applied patent CN112851255A discloses a self-insulating building material for high-cold areas and a preparation method thereof. The self-insulating building material adopts polystyrene particles as the insulating material, but polystyrene particles are organic insulating materials with poor stability and durability, which affects the insulating effect of the self-insulating building material and the service life of the building; and the amount of fly ash used is small, which is not conducive to the resource recycling of waste pollutants.

[0005] Therefore, for the energy-intensive construction industry, how to use industrial waste fly ash to prepare thermal insulation materials with excellent performance, high strength and low thermal conductivity has important ecological, economic and social benefits. Summary of the invention

[0006] In order to solve the shortcomings of the prior art, the main purpose of the present invention is to provide a self-insulating building material based on cement-fly ash waste and a preparation method thereof. The self-insulating building material of the present invention not only realizes the recycling of solid waste such as fly ash, reduces environmental pollution, reduces the production cost of building materials, and reduces production costs, but also the prepared material has the advantages of light weight, low thermal conductivity, excellent mechanical properties and good fire resistance.

[0007] To achieve the above object, the technical solution of the present invention is: A self-insulating building material based on cement-fly ash waste comprises the following components by weight: 60-80 parts of fly ash, 20-30 parts of cement, 10-20 parts of slag powder, 1-8 parts of silica fume, 3-10 parts of phosphogypsum, 10-15 parts of expanded perlite, 0.5-2 parts of foaming agent, 0.5-2 parts of accelerator, 0.5-1.5 parts of polycarboxylate water reducer, 3-5 parts of straw particles, and a water-cement ratio of 0.45-0.55.

[0008] The invention uses cement, fly ash and slag powder as main cementitious materials, uses expanded perlite as lightweight aggregate, and adds a variety of additives to prepare a green thermal insulation material with light weight, low thermal conductivity, high strength and fire resistance.

[0009] Preferably, the dry density of the thermal insulation material is 280-350 kg / m 3 The thermal conductivity is below 0.08w / (m﹒k) and the flame retardant grade is A.

[0010] Preferably, the cement is at least one of silicate cement and sulphoaluminate cement.

[0011] More preferably, the cement is a mixture of silicate cement and sulphoaluminate cement, with a mass ratio of 5-12: 1. By mixing silicate cement and sulphoaluminate cement, not only can the freeze-thaw resistance of the foamed concrete be improved and the service life be extended, but also the permeability of the foamed concrete can be reduced.

[0012] Preferably, the fly ash is grade II or above fly ash, with a density of 1.8-2.3 kg / m 3 , particle size 0.5-300μm, specific surface area 300-500m 2 / kg.

[0013] The mineral powder is S95 grade granulated blast furnace slag powder with a density of 2.8-2.9 kg / m 3 , specific surface area 400-450m 2 / kg, particle size is below 40μm.

[0014] By adding fly ash, slag powder and silica fume mineral admixtures into the material, they can stimulate each other and promote the increase of the early strength of the material, which helps to form more closed pores and improve the thermal insulation performance of the material; moreover, fly ash, slag powder and silica fume can significantly improve the later strength of the thermal insulation material; by adding an appropriate amount of phosphogypsum, it helps the expansion effect of calcium aluminate to offset the shrinkage of the material and improve the compressive strength of the material.

[0015] Preferably, the specific surface area of ​​the silica fume is 18m 2 / g~25m 2 / g, SiO 2 Content>92wt%.

[0016] Preferably, the expanded perlite is modified expanded perlite, and the preparation method is as follows: first, the silicone emulsion is configured into a diluent, the dried expanded perlite is placed in the diluent, and after vacuum treatment, it is filtered and dried to obtain hydrophobic expanded perlite; then the hydrophobic expanded perlite is immersed in a sodium methyl silicate solution for secondary modification, filtered, and dried to obtain the modified expanded perlite.

[0017] Preferably, the concentration of the organosilicon emulsion diluent is 0.1-0.6%, and the concentration of the sodium methyl silicate solution is 5-20%.

[0018] The invention reduces the water absorption of expanded perlite by modifying the expanded perlite, avoids the cracking and hollowing caused thereby, and improves the performance of the self-heat-insulating building material.

[0019] Preferably, the foaming agent comprises the following raw materials in percentage by mass: 30-60% sodium α-olefin sulfonate, 20-50% alcohol ether glycoside, 10-20% foam stabilizer, and 8-20% viscosity enhancer.

[0020] Preferably, the foam stabilizer is at least one of silicone polyether emulsion, coconut oil diethanolamine, fatty alcohol polyoxyethylene ether, and dodecanol; The viscosity enhancer is at least one of carboxymethyl cellulose, dodecyltrimethylammonium chloride and dodecylethanolamine.

[0021] More preferably, the self-insulating building material further comprises 2-5 parts of polypropylene fibers, wherein the polypropylene fibers are chopped, have a length of 5-8 mm, and a diameter of 38-40 mm.

[0022] Preferably, the straw particles are prepared by desugaring and crushing straw, and have a particle size of less than 100 μm.

[0023] Straw is agricultural waste, which comes from many sources and is difficult to process. The present invention uses it for thermal insulation materials after processing. Straw is a fiber material with a certain reinforcement effect, which can prevent the material from drying out and cracking. It itself has the characteristics of light weight and low thermal conductivity. Adding it to the material can reduce the quality and cost of the material and the effect of reducing the cracking of the material.

[0024] Preferably, the coagulant is a carbonate or aluminate coagulant.

[0025] More preferably, the accelerating setting agent is one or more of carbonate and potassium silicate.

[0026] Preferably, the self-insulating building material based on cement-fly ash waste includes, by weight: 70 parts of fly ash, 22.5 parts of silicate cement, 2.5 parts of sulphoaluminate cement, 15 parts of slag powder, 5 parts of silica fume, 6 parts of phosphogypsum, 13 parts of expanded perlite, 1.5 parts of foaming agent, 1 part of accelerator, 1 part of polycarboxylic acid water reducer, 4 parts of straw particles, and a water-cement ratio of 0.5.

[0027] The present invention also provides a method for preparing the self-insulating building material, comprising the following steps: S1. Cement, fly ash, slag powder, straw particles, expanded perlite and polycarboxylate water reducer are stirred and mixed to obtain dry powder material, and then appropriate amount of water is added to mix to obtain premixed slurry; S2, mixing the foaming agent and the accelerating setting agent with the remaining water, and injecting compressed air with an air compressor to prepare a foaming solution until the volume of the foaming solution is equivalent to the volume of the slurry in the previous step; S3, the foaming solution and the premixed slurry are evenly mixed to obtain a foaming slurry, which is poured into a mold and cured to form a self-insulating building material.

[0028] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts a composite modified foaming agent to improve the foaming ability and foam stabilizing effect of the foaming agent, effectively improve the interaction between the foam and cement particles, and improve the workability with the concrete slurry; by hydrophobic treatment of the expanded perlite, its water absorption rate is reduced, and shrinkage cracks due to a large amount of water loss during the coagulation and hardening process of the self-insulating building material are avoided; at the same time, the modified expanded perlite and the cementitious material mainly composed of cement, slag, and fly ash, and the polycarboxylic acid water reducer, under the action of the foaming agent, form tiny non-penetrating bubbles inside the self-insulating building material, thereby enhancing the thermal insulation performance of the self-insulating building material.

[0029] 2. The present invention uses a large amount of fly ash as raw material, which effectively reduces the production cost of self-insulating materials. It not only solves the current problem of fly ash accumulation and environmental pollution, but also increases the added value of fly ash utilization, realizes the resource utilization of process waste, greatly reduces production costs, saves energy and protects the environment, and reduces pollution; moreover, the use of fly ash, slag, silica fume and phosphogypsum not only saves cement, but also overcomes the shrinkage of cement and improves the crack resistance of the material.

[0030] 3. The present invention ensures the compressive strength and thermal insulation effect of the self-insulating building material under the premise of adding a large amount of fly ash. The dry density of the prepared thermal insulation material is 280-350kg / m 3 The compressive strength is 1.5-3.0MPa, the thermal conductivity is below 0.08w / (m﹒k), and the flame retardant grade is A. The lightweight insulation material of the present invention has significant heat insulation effect, can effectively reduce the energy consumption of air conditioning in summer and heating in winter, has strong energy-saving and environmental protection effects, and is an ideal wall insulation material. DETAILED DESCRIPTION

[0031] The embodiments of the present invention will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention.

[0032] Embodiment 1: A self-insulating building material based on cement-fly ash waste, comprising the following raw materials: 60kg fly ash, 17kg silicate cement, 3kg sulphoaluminate cement, 10kg slag powder, 2kg silica fume, 3 parts of phosphogypsum, 10kg modified expanded perlite, 0.5kg foaming agent, 0.5kg accelerator, 0.5kg polycarboxylate water reducer, 3kg straw pellets, and 43kg water; The fly ash is secondary fly ash; the mineral powder is blast furnace slag powder, and the particle size is less than 40 μm; the foaming agent is composed of 0.175 kg of sodium α-olefin sulfonate, 0.15 kg of coconut oil polyglucoside, 0.1 kg of silicone polyether emulsion and 0.075 kg of carboxymethyl cellulose in percentage by weight; the accelerating setting agent is potassium aluminate; the straw particles are made by desugaring and crushing straw, and the particle size is less than 100 μm; The preparation method of the modified expanded pearl is as follows: first, the silicone emulsion is configured into a diluent with a concentration of 0.2%, the dried expanded perlite is placed in the diluent, and after vacuum treatment for 1 hour, the expanded perlite is filtered out, and dried in a constant temperature box at 105°C for 1 hour to obtain hydrophobic expanded perlite; then the hydrophobic expanded perlite is placed in a sodium methyl silicate with a concentration of 5% and immersed for 1 hour, and secondary modification is performed, filtered, and dried to obtain the modified expanded perlite.

[0033] The self-insulating building material is prepared by the following method: S1. Add the weighed cement, fly ash, slag powder, silica fume, phosphogypsum, straw particles, modified expanded perlite, polycarboxylate water reducer and potassium aluminate into a mixing tank for pre-mixing, and then add 25.8 kg of water for uniform mixing to obtain a premixed slurry; S2, mixing the weighed foaming agent with the remaining water, stirring at a speed of 300 rpm, and injecting compressed air using an air compressor to prepare a foaming solution until the volume of the foaming solution is equivalent to the volume of the slurry in the previous step; S3, the foaming solution and the premixed slurry are mixed evenly, the stirring speed is 80rpm to obtain the foaming slurry, and the foaming slurry is poured into a mold and cured to obtain a self-insulating building material.

[0034] Embodiment 2: A self-insulating building material based on cement-fly ash waste, comprising: 80kg fly ash, 27.5kg silicate cement, 2.5kg sulphoaluminate cement, 20kg slag powder, 8kg silica fume, 9kg phosphogypsum, 15kg modified expanded perlite, 2kg foaming agent, 2kg accelerator, 1.5kg polycarboxylate water reducer, 5kg straw pellets, and 80kg water; The fly ash is secondary fly ash; the mineral powder is blast furnace slag powder, and the particle size is less than 40 μm; the foaming agent is composed of 1.2 kg of sodium α-olefin sulfonate, 0.6 kg of coconut oil polyglucoside, 0.16 kg of silicone polyether emulsion and 0.04 kg of carboxymethyl cellulose in percentage by weight; the accelerating setting agent is potassium aluminate; the straw particles are made by desugaring and crushing straw, and the particle size is less than 100 μm; The preparation method of the modified expanded pearl is as follows: first, the silicone emulsion is configured into a diluent with a concentration of 1%, the dried expanded perlite is placed in the diluent, and after vacuum treatment for 1 hour, the expanded perlite is filtered out, and dried in a constant temperature box at 105° C. for 1 hour to obtain hydrophobic expanded perlite; then the hydrophobic expanded perlite is placed in a sodium methyl silicate with a concentration of 20% and immersed for 1 hour, and secondary modification is performed, filtered, and dried to obtain the modified expanded perlite.

[0035] The self-insulating building material is prepared by the following method: S1. Stir and mix the weighed cement, fly ash, slag powder, silica fume, phosphogypsum, straw particles, modified expanded perlite, polycarboxylate water reducer and accelerator to obtain a dry powder material, then add 56 kg of water and mix evenly to obtain a premixed slurry; S2, mixing the weighed foaming agent with the remaining water, and injecting compressed air using an air compressor to prepare a foaming solution until the volume of the foaming solution is equivalent to the volume of the slurry in the previous step; S3, the foaming solution and the premixed slurry are evenly mixed to obtain a foaming slurry, which is poured into a mold and cured to form a self-insulating building material.

[0036] Embodiment 3: A self-insulating building material based on cement-fly ash waste, comprising: 70kg fly ash, 22.5kg silicate cement, 2.5kg sulphoaluminate cement, 15kg slag, 5kg silica fume, 6kg phosphogypsum, 13kg modified expanded perlite, 1.2kg foaming agent, 1.5kg accelerator, 1kg polycarboxylate water reducer, 4kg polypropylene fiber, 4kg straw particles, and 61kg water.

[0037] Among them, the fly ash is secondary fly ash; the mineral powder is blast furnace slag powder, and the particle size is less than 40μm; the foaming agent is composed of 0.6kg of sodium α-olefin sulfonate, 0.36kg of coconut oil polyglucoside, 0.156kg of silicone resin polyether emulsion and 0.084kg of carboxymethyl cellulose in percentage by mass; the accelerator is potassium aluminate; the straw particles are made by desugaring and crushing straw, and the particle size is less than 100μm.

[0038] The preparation method of the modified expanded perlite is as follows: First, the silicone emulsion is prepared into a diluent with a concentration of 0.5%, and the dried expanded perlite is placed in the diluent and vacuumed for 1 hour. The expanded perlite is then filtered out and dried in a constant temperature box at 105°C for 1 hour to obtain hydrophobic expanded perlite. The hydrophobic expanded perlite is then immersed in 10% sodium methyl silicate for 1 hour for secondary modification, filtered, and dried to obtain modified expanded perlite.

[0039] The self-insulating building material is prepared by the following method: S1. Stir and mix the weighed cement, fly ash, slag powder, silica fume, phosphogypsum, straw particles, modified expanded perlite, polycarboxylate water reducer and accelerator to obtain a dry powder material, then add 37.9 kg of water and mix evenly to obtain a premixed slurry; S2, mixing the weighed foaming agent with the remaining water, and injecting compressed air using an air compressor to prepare a foaming solution until the volume of the foaming solution is equivalent to the volume of the slurry in the previous step; S3, the foaming solution and the premixed slurry are evenly mixed to obtain a foaming slurry, which is poured into a mold and cured to form a self-insulating building material.

[0040] Comparative Example 1: The same as Example 3, except that the foaming agent is only sodium α-olefin sulfonate.

[0041] Comparative Example 2: The same as Example 3, except that unmodified expanded perlite is used.

[0042] Comparative Example 3: Same as Example 3, except that no slag is used.

[0043] The performance tests were carried out on the self-insulating building materials of the above embodiments and comparative examples, and the results are shown in Table 1.

[0044] Table 1 Performance test results of self-insulating building materials prepared in Examples and Comparative Examples

[0045] It can be seen from the data in Table 1 that the pore structure of the unmodified expanded perlite in Comparative Example 1 is not effectively modified, and the synergistic balance between the foaming agents in Comparative Examples 2-3 is broken, resulting in an uneven pore structure, so the thermal conductivity and strength properties show a weakening trend. The present invention uses a composite foaming agent and modified expanded perlite to not only prepare a lightweight self-insulating building material to meet the wall insulation requirements, but also realizes the reuse of solid wastes such as high-doped fly ash, reduces environmental pollution, and reduces the production cost of building materials.

[0046] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A self-insulating building material based on cement-fly ash waste, characterized in that: The composition includes the following components by weight: 60-70 parts of fly ash, 20-30 parts of cement, 10-20 parts of slag powder, 1-8 parts of silica fume, 3-10 parts of phosphogypsum, 10-15 parts of expanded perlite, 0.5-2 parts of foaming agent, 0.5-2 parts of accelerating setting agent, 0.5-1.5 parts of polycarboxylic acid water reducer, 3-5 parts of straw particles, and a water-cement ratio of 0.45-0.

55.

2. The self-insulating building material based on cement-fly ash waste according to claim 1, characterized in that: The cement is selected from at least one of silicate cement and sulphoaluminate cement; the fly ash is selected from one of primary fly ash and secondary fly ash; and the mineral powder is blast furnace slag powder with a particle size of less than 40 μm.

3. The self-insulating building material based on cement-fly ash waste according to claim 1, characterized in that: The cement is a mixture of silicate cement and sulphoaluminate cement, with a mass ratio of 5-12:

1.

4. The self-insulating building material based on cement-fly ash waste according to claim 1, characterized in that: The expanded perlite is a modified expanded perlite, and the preparation method is as follows: the preparation method of the modified expanded perlite is as follows: first, the silicone emulsion is configured into a diluent, the dry expanded perlite is placed in the diluent, and after vacuum treatment, it is filtered and dried to obtain hydrophobic expanded perlite; then the hydrophobic expanded perlite is immersed in a sodium methyl silicate solution, subjected to secondary modification, filtered, and dried to obtain the modified expanded perlite.

5. The self-insulating building material based on cement-fly ash waste according to claim 4, characterized in that: The concentration of the organosilicon emulsion diluent is 0.1-0.6%, and the concentration of the sodium methyl silicate solution is 5-20%.

6. The self-insulating building material based on cement-fly ash waste according to claim 1, characterized in that: The foaming agent comprises the following raw materials in percentage by mass: 30-60% sodium α-olefin sulfonate, 20-50% alcohol ether glycoside, 10-20% foam stabilizer, and 8-20% viscosity enhancer.

7. The self-insulating building material based on cement-fly ash waste according to claim 6, characterized in that: The foam stabilizer is at least one of silicone resin polyether emulsion, coconut oil diethanolamine, fatty alcohol polyoxyethylene ether, and dodecanol.

8. The self-insulating building material based on cement-fly ash waste according to claim 6, characterized in that: The viscosity enhancer is at least one of carboxymethyl cellulose, lauroyl diethanolamine and polyacrylamide.

9. The self-insulating building material based on cement-fly ash waste according to claim 1, characterized in that: The straw particles are prepared by desugaring and crushing straw, and the particle size is below 100 μm; the coagulant is a carbonate or aluminate coagulant.

10. The method for preparing the self-insulating building material based on cement-fly ash waste according to any one of claims 1 to 9, characterized in that: The steps include: S1. Mix cement, fly ash, slag powder, straw particles, expanded perlite, accelerator and polycarboxylate water reducer to obtain dry powder material, then add appropriate amount of water and stir to obtain premixed slurry; S2, mixing the foaming agent with the remaining water, and injecting compressed air using an air compressor to prepare a foaming solution until the volume of the foaming solution is equivalent to the volume of the slurry in the previous step; S3, the foaming solution and the premixed slurry are stirred evenly to obtain a foaming slurry, which is poured into a mold and cured to form a self-insulating building material.

Images