A cementing material for preparing a multi-element solid waste assembled wall and a preparation method thereof

Abstract

The application relates to the technical field of building materials, in particular to a cementing material for preparing an assembled wall body from multiple solid wastes and a preparation method; the cementing material is prepared from 25-55 parts of fly ash, 25-65 parts of blast furnace slag, 8-10 parts of lime, 1-5 parts of desulfurization gypsum, 3-6 parts of a first mixture, 2-5 parts of a second mixture and 5-8 parts of an alkali activator; the mass ratio of metakaolin, bentonite and superfine calcium carbonate in the first mixture is 3:2:1; the mass ratio of vermiculite, expanded perlite and glass beads in the second mixture is 2:2:1. The cementing material has a more stable microstructure through the synergistic activation of Ca and Na, and the addition of the first mixture and the second mixture. 2+ and Na + The C-S-H and C(N)-A-S-H gels form a three-dimensional network, needle-shaped ettringite crystals fill pores, and the anchoring effect of brucite phase is combined, so that the mechanical properties, such as strength and durability, of the material are significantly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to a cementing material for preparing an assembled wall body from multiple solid wastes and a preparation method thereof. BACKGROUND

[0002] With the rapid development of the construction industry, the demand for wall materials is increasing. Traditional wall materials such as cement-based materials consume a large amount of natural resources during production and emit a large amount of carbon dioxide, which does not meet the green and environmentally friendly development concept. At the same time, solid wastes such as fly ash and blast furnace slag generated during industrial production accumulate like mountains, not only occupying a large amount of land, but also causing environmental pollution.

[0003] Geopolymer material, as a new type of inorganic cementing material, has the advantages of high strength, good corrosion resistance, low carbon and environmental protection, and is expected to replace traditional cement-based materials. However, the preparation of geopolymer materials at present mostly depends on high-purity raw materials and complex processes, which limits its large-scale application. In addition, in a lower temperature environment, the existing geopolymer cementing material prepared wall surface is prone to cracking, and the prepared wall body has poor thermal insulation effect, affecting the energy-saving performance of the building. Therefore, developing a technology for preparing a geopolymer cementing material from multiple solid wastes, which can prevent wall surface cracking at a lower temperature and make the wall body have good thermal insulation effect, has important significance for realizing solid waste resource utilization and promoting the green and energy-saving development of the construction industry. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a cementing material for preparing an assembled wall body from multiple solid wastes and a preparation method thereof. The cementing material uses multiple solid wastes such as fly ash and blast furnace slag as the main raw material, adds a first mixture and a second mixture prepared from multiple raw materials as intermediate products, and through the synergistic excitation of Ca 2+ and Na + , has good mechanical properties and durability, can prevent wall surface cracking at a lower temperature, and the prepared assembled wall body has good thermal insulation effect. The purpose of the present application can be achieved by the following technical scheme:

[0005] A cementing material for preparing an assembled wall body from multiple solid wastes, comprising the following components in terms of weight percentage: fly ash 25-55 parts, blast furnace slag 25-65 parts, lime 8-10 parts, desulfurization gypsum 1-5 parts, first mixture 3-6 parts, second mixture 2-5 parts, and alkali activator 5-8 parts; the mass ratio of metakaolin, bentonite and ultra-fine calcium carbonate in the first mixture is 3:2:1; the mass ratio of vermiculite, expanded perlite and glass microbeads in the second mixture is 2:2:1.

[0006] Further, the alkali activator is NaOH.

[0007] A preparation method of a cementitious material for preparing a multi-element solid waste fabricated wall, comprising the following steps:

[0008] S1, raw material pretreatment:

[0009] S1.1, the fly ash is subjected to grading treatment, the fine powder with a particle size ≤45 μm and the coarse powder with a particle size >45 μm are screened out by an air flow classifier, the fine powder is reserved, and the coarse powder is subjected to air flow crushing to a particle size ≤45 μm and then reserved;

[0010] S1.2, the blast furnace slag is subjected to magnetic separation and iron removal treatment, the ferromagnetic impurities are removed, then the blast furnace slag is crushed to a particle size ≤10 mm, and then subjected to air flow crushing to a particle size ≤30 μm and reserved;

[0011] S1.3, the desulfurization gypsum is subjected to calcination treatment at 150-180 ℃ for 2-3 hours to remove crystal water, and then ground to a particle size ≤20 μm after cooling and reserved;

[0012] S1.4, the metakaolin is calcined at 800-850 ℃ for 1-2 hours, and then mixed with the bentonite and the ultra-fine calcium carbonate at a mass ratio of 3:2:1, put into a planetary ball mill, and subjected to ball milling at a ball-to-material ratio of 3:1 and a rotating speed of 300 r / min for 30-40 minutes to obtain a first mixture and reserve;

[0013] S1.5, the vermiculite is crushed to a particle size of 3-5 mm, preheated at 300-400 ℃ for 1-1.5 hours, the expanded perlite is sieved to obtain particles with a particle size of 2-4 mm, and the glass microbeads are subjected to surface modification treatment, soaked in a silane coupling agent solution for 30-60 minutes, taken out and dried, and then mixed with the treated vermiculite, expanded perlite and glass microbeads at a mass ratio of 2:2:1 to obtain a second mixture and reserve;

[0014] S2, the pretreated fly ash, blast furnace slag, desulfurization gypsum, first mixture and second mixture are weighed and put into a double-shaft paddle mixer and mixed at a rotating speed of 150-200 r / min for 15-20 minutes, and then put into a vacuum oven and dried at 105±5 ℃ and a vacuum degree of -0.08 to -0.06 MPa until the final water content is ≤1%;

[0015] S3, stage ball milling treatment:

[0016] S3.1, the dried fly ash and blast furnace slag are put into a ball mill, ball milling is carried out at a ball-to-material ratio of 4:1 and a rotating speed of 200 r / min for 40-50 minutes to obtain a first-stage mixed powder;

[0017] S3.2, adding lime and desulfurization gypsum to the first-stage mixed powder, and continuing to ball mill for 30-35 minutes at a ball-to-material ratio of 3:1 and a rotation speed of 180 r / min to obtain a second-stage mixed powder;

[0018] S3.3, adding the first mixture and the second mixture to the second-stage mixed powder, and continuing to ball mill for 25-30 minutes at a ball-to-material ratio of 2.5:1 and a rotation speed of 150 r / min to obtain the composite mineral powder, which has a specific surface area of ≥450 m 2 / kg and a D50 of 10-12 μm;

[0019] S4, dissolving industrial caustic soda NaOH in deionized water to prepare a NaOH solution with a mass concentration of 30%-40%, and standing for 24 hours; then slowly adding the NaOH solution into the composite mineral powder in proportion while stirring, at a stirring speed of 80-100 r / min and a stirring time of 15-20 minutes;

[0020] S5, placing the above mixture into a wet ball mill at a ball-to-material ratio of 5:1 and a rotation speed of 120 r / min to ball mill for 60-90 minutes to obtain a slurry; and placing the slurry into a sealed container to age for 24-48 hours at 20-25 °C to obtain the cementitious material.

[0021] Further, the grinding balls of the planetary ball mill in step S1.4 are zirconia balls with diameters of 10 mm, 5 mm and 3 mm, and the mass ratio of the three kinds of grinding balls is 2:2:1.

[0022] Further, the silane coupling agent solution in step S1.5 is a KH-550 ethanol solution with a mass fraction of 2%-3%, and the volume ratio of ethanol to water is 9:1.

[0023] Further, the amount of the NaOH solution added in step S4 is 5%-8% of the total mass of the raw materials, as calculated in terms of Na2O.

[0024] Further, the medium for the wet ball milling in step S5 is deionized water, and the solid-to-liquid ratio of the slurry is 1:1.2-1:1.5.

[0025] A cementitious material for preparing a fabricated wall body from multiple solid wastes.

[0026] Further, the specific steps for preparing the fabricated wall body using the cementitious material are as follows: mixing the aged cementitious material slurry with reinforcing fibers at a mass ratio of 100:1-100:3, uniformly stirring, and then injecting into a mold, curing at 60-80 °C and a relative humidity of ≥90% for 24-48 hours, then demolding, and curing under natural conditions for 28 days to obtain the fabricated wall body.

[0027] Further, the reinforcing fibers are glass fibers or basalt fibers, and the length is 6-12 mm.

[0028] Advantages of the present application:

[0029] 1. The synergistic effect of Ca 2+ and Na + , and the addition of the first mixture (metakaolin, bentonite, and superfine calcium carbonate in a ratio of 3:2:1) and the second mixture (vermiculite, expanded perlite, and glass microbeads in a ratio of 2:2:1) makes the cementitious material form a more stable microstructure. As can be seen from the SEM image of the hydration product, C-S-H and C(N)-A-S-H gel form a three-dimensional network, and needle-shaped ettringite crystals fill the pores, combined with the anchoring effect of the brucite phase, significantly improving the mechanical properties of the material, such as strength and durability.

[0030] 2. The pozzolanic activity of metakaolin in the first mixture reacts with Ca 2+ to generate more cementitious products, combined with the pore-filling effect of superfine calcium carbonate, significantly improving the material density; the water retention of bentonite reduces the shrinkage stress caused by water loss, combined with the elastic buffer structure formed by the lightweight aggregate in the second mixture, reducing the brittleness of the material while further inhibiting the generation of micro-cracks in low-temperature environments, so that the wall maintains structural integrity during low-temperature construction or use.

[0031] 3. The lightweight and porous components such as vermiculite and expanded perlite in the second mixture construct a continuous thermal barrier, and its closed pore structure effectively blocks the heat conduction path; the first mixture optimizes the microstructure of the cementitious system to avoid the mechanical performance decline caused by the addition of thermal insulation components while ensuring the strength of the material. The two work together to make the wall meet the thermal insulation requirements of the "Code for Thermal Design of Civil Buildings" and the strength standards of the "Technical Specification for Fabricated Concrete Structures".

[0032] 4. The plasticity of bentonite improves the flowability of the material during mixing, making it easier to mix the cementitious system containing lightweight thermal insulation aggregate; the water retention characteristics of the first mixture prolong the setting time, providing sufficient hydration environment for the lightweight particles in the second mixture, reducing interface defects caused by rapid drying, and improving the forming quality of the wall. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0034] Figure 1The XRD diffraction pattern of the fly ash shows that the main crystal phase is quartz and mullite, and there are more glass phase materials, which is a high-quality raw material for preparing alkali-activated cementitious materials.

[0035] Figure 2 The XRD diffraction pattern of the blast furnace slag shows that the main crystal phase is quartz, calcite and mullite, and there are more glass phase materials, which is a high-quality raw material for preparing alkali-activated cementitious materials.

[0036] Figure 3 The XRD diffraction pattern of the lime shows that the main phase is calcium hydroxide and calcium oxide, and there are more crystal phases and less glass phase materials, which shows that the lime can not only provide a good alkaline environment after hydration, but also provide sufficient Ca 2+ for the alkali-activated hydration reaction.

[0037] Figure 4 The XRD diffraction pattern of the desulfurization gypsum shows that the main phase is calcium sulfate dihydrate, calcium oxide and quartz, which shows that the desulfurization gypsum can release Ca 2+ in the alkali-activated environment, provide calcium source for the hydration reaction, and react with aluminum ions (Al 3+ ) and silicon ions (Si 4+ ) in the alkaline solution to generate ettringite, which can play a role in retarding the setting and solve the problem of too fast setting rate of the alkali-activated cementitious material.

[0038] Figure 5 The SEM image of the hydration product shows the microstructure of the three-dimensional network formed by the symbiotic C-S- and N(C)-A-S- gels and the needle-shaped ettringite crystals filling the pores, and the anchoring effect of the brucite phase, which confirms the mechanism of mechanical performance improvement of the dual-alkali synergistic activation. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0040] A cementitious material for preparing an assembled wall body from multiple solid wastes comprises the following components in percentage by weight: 25-55 parts of fly ash, 25-65 parts of blast furnace slag, 8-10 parts of lime, 1-5 parts of desulfurization gypsum, 3-6 parts of a first mixture, 2-5 parts of a second mixture, and 5-8 parts of an alkali activator; the mass ratio of metakaolin, bentonite and ultra-fine calcium carbonate in the first mixture is 3:2:1; and the mass ratio of vermiculite, expanded perlite and glass beads in the second mixture is 2:2:1.

[0041] As a preferred scheme of the present application, the alkali activator is NaOH.

[0042] A preparation method of a cementitious material for preparing a multi-element solid waste assembled wall body, comprising the following steps:

[0043] S1, raw material pretreatment:

[0044] S1.1, the fly ash is subjected to grading treatment, the fine powder with a particle size ≤45 μm and the coarse powder with a particle size >45 μm are screened out by an air flow classifier, the fine powder is reserved for use, and the coarse powder is subjected to air flow crushing to a particle size ≤45 μm and then reserved for use;

[0045] S1.2, the blast furnace slag is subjected to magnetic separation and iron removal treatment to remove the ferromagnetic impurities therein, then is crushed to a particle size ≤10 mm, and then is subjected to air flow crushing to a particle size ≤30 μm and reserved for use;

[0046] S1.3, the desulfurization gypsum is subjected to calcination treatment at 150-180 ℃ for 2-3 hours to remove crystal water, and then is ground to a particle size ≤20 μm after cooling and reserved for use;

[0047] S1.4, the metakaolin is calcined at 800-850 ℃ for 1-2 hours, and then is mixed with the bentonite and the ultra-fine calcium carbonate at a mass ratio of 3:2:1, and then is put into a planetary ball mill at a ball-to-material ratio of 3:1 and a rotating speed of 300 r / min for ball milling for 30-40 minutes to obtain a first mixture reserved for use;

[0048] S1.5, the vermiculite is crushed to a particle size of 3-5 mm, is preheated at 300-400 ℃ for 1-1.5 hours, the expanded perlite is sieved to obtain particles with a particle size of 2-4 mm, and the glass microbeads are subjected to surface modification treatment by being soaked in a silane coupling agent solution for 30-60 minutes and then dried; then the treated vermiculite, expanded perlite and glass microbeads are mixed at a mass ratio of 2:2:1 to obtain a second mixture reserved for use;

[0049] S2, the pretreated fly ash, blast furnace slag, desulfurization gypsum, first mixture and second mixture are weighed and put into a double-shaft paddle mixer at a rotating speed of 150-200 r / min for mixing for 15-20 minutes, and then are put into a vacuum oven for drying at 105±5 ℃ and a vacuum degree of -0.08 to -0.06 MPa until the final water content is ≤1%;

[0050] S3, stage ball milling treatment:

[0051] S3.1, the dried fly ash and blast furnace slag are put into a ball mill at a ball-to-material ratio of 4:1 and a rotating speed of 200 r / min for ball milling for 40-50 minutes to obtain a first-stage mixed powder;

[0052] S3.2, adding lime and desulfurization gypsum to the first-stage mixed powder, and continuing to ball mill at a ball-to-material ratio of 3:1 and a rotating speed of 180 r / min for 30-35 minutes to obtain a second-stage mixed powder;

[0053] S3.3, adding the first mixture and the second mixture to the second-stage mixed powder, and continuing to ball mill at a ball-to-material ratio of 2.5:1 and a rotating speed of 150 r / min for 25-30 minutes to obtain the composite mineral powder, which has a specific surface area of greater than or equal to 450 m 2 / kg and a D50 of 10-12 μm;

[0054] S4, dissolving industrial caustic soda NaOH in deionized water to prepare a NaOH solution with a mass concentration of 30%-40%, and standing for 24 hours; then slowly adding the NaOH solution into the composite mineral powder in proportion, while stirring at a speed of 80-100 r / min for 15-20 minutes;

[0055] S5, placing the above mixture into a wet ball mill at a ball-to-material ratio of 5:1 and a rotating speed of 120 r / min for ball milling for 60-90 minutes to obtain a slurry; and placing the slurry into a sealed container and aging at 20-25 °C for 24-48 hours to obtain the cementitious material.

[0056] As a preferred scheme of the present application, the grinding balls of the planetary ball mill in step S1.4 are zirconia balls with diameters of 10 mm, 5 mm and 3 mm, and the mass ratio of the three kinds of grinding balls is 2:2:1.

[0057] As a preferred scheme of the present application, the silane coupling agent solution in step S1.5 is a KH-550 ethanol solution with a mass fraction of 2%-3%, and the volume ratio of ethanol to water is 9:1.

[0058] As a preferred scheme of the present application, the amount of the NaOH solution added in step S4 is 5%-8% of the total mass of the raw materials, as converted into Na2O.

[0059] As a preferred scheme of the present application, the medium for the wet ball milling in step S5 is deionized water, and the solid-to-liquid ratio of the slurry is 1:1.2-1:1.5.

[0060] The present scheme will be described in detail below in combination with multiple embodiments and comparative examples:

[0061] Chemical composition of various solid waste raw materials (%)

[0062] Chemical composition SiO2 Al2O3 CaO Fe2O3 TiO2 MgO Na2O SO3 Fly ash 46.74 39.74 4.10 3.24 1.40 0.85 0.36 0.86 Blast furnace slag 30.94 14.82 34.48 0.53 2.12 11.45 1.21 3.29 Lime 11.02 1.71 80.16 0.32 0.94 2.32 1.41 0.98 Desulfurization gypsum 11.81 1.45 28.20 0.37 0.49 3.53 4.0 49.15

[0063] Example 1:

[0064] The preparation raw materials are: fly ash 26.5 parts, blast furnace slag 63.5 parts, lime 10 parts, desulfurization gypsum 0 parts, first mixture 3 parts, second mixture 5 parts, alkali activator 5 parts; the mass ratio of metakaolin, bentonite and superfine calcium carbonate in the first mixture is 3:2:1; the mass ratio of vermiculite, expanded perlite and glass beads in the second mixture is 2:2:1.

[0065] A preparation method of a cementitious material for preparing a fabricated wall body from multiple solid wastes, comprising the following steps:

[0066] S1, raw material pretreatment:

[0067] S1.1, the fly ash is subjected to grading treatment, the fine powder with a particle size of ≤45 μm and the coarse powder with a particle size of >45 μm are screened out by an air flow classifier, the fine powder is reserved, and the coarse powder is subjected to air flow grinding to a particle size of ≤45 μm and then reserved;

[0068] S1.2, the blast furnace slag is subjected to magnetic separation and iron removal treatment, the ferromagnetic impurities are removed, then the blast furnace slag is broken to a particle size of ≤10 mm, and then subjected to air flow grinding to a particle size of ≤30 μm and reserved;

[0069] S1.3, the desulfurization gypsum is subjected to calcination treatment at 150 ℃ for 3 hours to remove crystal water, and then ground to a particle size of ≤20 μm after cooling and reserved;

[0070] S1.4, the metakaolin is calcined at 800-850 ℃ for 2 hours, and then mixed with bentonite and superfine calcium carbonate at a mass ratio of 3:2:1, put into a planetary ball mill, and subjected to ball milling at a ball-to-material ratio of 3:1 and a rotating speed of 300 r / min for 40 minutes to obtain a first mixture and reserve;

[0071] S1.5, the vermiculite is broken to a particle size of 3-5 mm, preheated at 300-400 ℃ for 1-1.5 hours; the expanded perlite is sieved to obtain particles with a particle size of 2-4 mm; the glass beads are subjected to surface modification treatment, soaked in a silane coupling agent solution for 30-60 minutes, taken out and dried; then the treated vermiculite, expanded perlite and glass beads are mixed at a mass ratio of 2:2:1 to obtain a second mixture and reserve;

[0072] S2, the pretreated fly ash, blast furnace slag, desulfurization gypsum, first mixture and second mixture are weighed and put into a double-shaft paddle mixer and mixed at a rotating speed of 200 r / min for 20 minutes, and then put into a vacuum oven and dried at 105±5 ℃ and a vacuum degree of -0.08 to -0.06 MPa until the final water content is ≤1%;

[0073] S3, stage ball milling treatment:

[0074] S3.1, put the dried fly ash and blast furnace slag into a ball mill, with a ball-to-material ratio of 4:1, a rotation speed of 200 r / min, and ball milling for 40-50 minutes to obtain a first-stage mixed powder;

[0075] S3.2, add lime and desulfurization gypsum to the first-stage mixed powder, continue ball milling at a ball-to-material ratio of 3:1, a rotation speed of 180 r / min, and ball milling for 30-35 minutes to obtain a second-stage mixed powder;

[0076] S3.3, add a first mixture and a second mixture to the second-stage mixed powder, with a ball-to-material ratio of 2.5:1, a rotation speed of 150 r / min, and ball milling for 25-30 minutes to obtain a composite mineral powder, with a specific surface area of ≥450 m2 / kg and a D50 of 10-12 μm; 2

[0077] S4, dissolve industrial caustic soda NaOH in deionized water to prepare a NaOH solution with a mass concentration of 30%-40%, and let it stand for 24 hours; then slowly add the NaOH solution into the composite mineral powder in proportion, while stirring at a speed of 80-100 r / min for 15-20 minutes;

[0078] S5, put the above mixture into a wet ball mill, with a ball-to-material ratio of 5:1, a rotation speed of 120 r / min, and ball milling for 60 minutes to obtain a slurry; put the slurry into a sealed container, and let it stand for 48 hours at 20℃ to obtain the cementitious material.

[0079] Mix the slurry of the cementitious material after standing with reinforcing fibers in a mass ratio of 100:3, uniformly stir, and then pour into a mold, and cure at 80℃ and a relative humidity of ≥90% for 48 hours, then demold, and cure for 28 days under natural conditions to obtain a fabricated wall.

[0080] Example 2:

[0081] The raw materials for preparation are: fly ash 30 parts, blast furnace slag 50 parts, lime 9 parts, desulfurization gypsum 3 parts, a first mixture 4 parts, a second mixture 5 parts, and alkali activator 5 parts; the mass ratio of metakaolin, bentonite and ultra-fine calcium carbonate in the first mixture is 3:2:1; the mass ratio of vermiculite, expanded perlite and glass beads in the second mixture is 2:2:1.

[0082] The preparation method of the cementitious material is the same as in Example 1.

[0083] Mix the slurry of the cementitious material after standing with reinforcing fibers in a mass ratio of 100:3, uniformly stir, and then pour into a mold, and cure at 80℃ and a relative humidity of ≥90% for 48 hours, then demold, and cure for 28 days under natural conditions to obtain a fabricated wall.

[0084] Example 3:​

[0085] The raw materials for preparation are: fly ash 50 parts, blast furnace slag 60 parts, lime 10 parts, desulfurization gypsum 5 parts, first mixture 6 parts, second mixture 2 parts, alkali activator 5 parts; the mass ratio of metakaolin, bentonite and superfine calcium carbonate in the first mixture is 3:2:1; the mass ratio of vermiculite, expanded perlite and glass microbeads in the second mixture is 2:2:1.

[0086] The preparation method of the cementitious material is the same as that in Embodiment 1.

[0087] The aged cementitious material slurry is mixed with the reinforcing fiber at a mass ratio of 100:3, and then poured into a mold after uniform stirring, and cured at 80°C and a relative humidity of ≥90% for 48 hours, and then demolded, and cured under natural conditions for 28 days to obtain the fabricated wall.

[0088] Comparative Example 1:

[0089] The raw materials for preparation are: fly ash 60 parts, blast furnace slag 30 parts, lime 10 parts, desulfurization gypsum 5 parts, first mixture 6 parts, second mixture 2 parts, alkali activator 5 parts; the mass ratio of metakaolin, bentonite and superfine calcium carbonate in the first mixture is 3:2:1; the mass ratio of vermiculite, expanded perlite and glass microbeads in the second mixture is 2:2:1.

[0090] The preparation method of the cementitious material is the same as that in Embodiment 1.

[0091] The aged cementitious material slurry is mixed with the reinforcing fiber at a mass ratio of 100:3, and then poured into a mold after uniform stirring, and cured at 80°C and a relative humidity of ≥90% for 48 hours, and then demolded, and cured under natural conditions for 28 days to obtain the fabricated wall.

[0092] Comparative Example 2:

[0093] The raw materials for preparation are: blast furnace slag 30 parts, alkali activator 5 parts.

[0094] The cementitious material is prepared only using blast furnace slag and alkali activator as raw materials.

[0095] The aged cementitious material slurry is mixed with the reinforcing fiber at a mass ratio of 100:3, and then poured into a mold after uniform stirring, and cured at 80°C and a relative humidity of ≥90% for 48 hours, and then demolded, and cured under natural conditions for 28 days to obtain the fabricated wall.

[0096] Comparative Example 3: ordinary Portland cement 100 parts

[0097] The fabricated wall is prepared using ordinary Portland cement.

[0098] Comparative Example 4

[0099] The raw materials for preparation are: fly ash 60 parts, blast furnace slag 30 parts, lime 10 parts, desulfurization gypsum 5 parts, the first mixture 6 parts, alkali activator 5 parts; the mass ratio of metakaolin, bentonite and superfine calcium carbonate in the first mixture is 3:2:1.

[0100] The preparation method of the cementitious material is the same as that in Example 1.

[0101] The aged cementitious material slurry is mixed with the reinforcing fiber at a mass ratio of 100:3, and then poured into a mold after uniform stirring, and cured at 80℃ and relative humidity ≥90% for 48 hours, and then demolded, and cured under natural conditions for 28 days to obtain the fabricated wall.

[0102] Comparative Example 5

[0103] The raw materials for preparation are: fly ash 26.5 parts, blast furnace slag 63.5 parts, lime 10 parts, desulfurization gypsum 0 parts, the second mixture 5 parts, alkali activator 5 parts; the mass ratio of metakaolin, bentonite and superfine calcium carbonate in the first mixture is 3:2:1; the mass ratio of vermiculite, expanded perlite and glass microbeads in the second mixture is 2:2:1.

[0104] The preparation method of the cementitious material is the same as that in Example 1.

[0105] The aged cementitious material slurry is mixed with the reinforcing fiber at a mass ratio of 100:3, and then poured into a mold after uniform stirring, and cured at 80℃ and relative humidity ≥90% for 48 hours, and then demolded, and cured under natural conditions for 28 days to obtain the fabricated wall.

[0106] The fabricated walls prepared in Examples 1-3 and Comparative Examples 1-5 are tested for performance, and the test results are shown in Table 1:

[0107] Table 1:

[0108]

[0109] Conclusion:

[0110] 1. According to the addition ratios in the examples and comparative examples and the attached Figure 5 It can be seen that: by adding Ca 2+ and Na +synergistic effect of the first mixture (metakaolin, bentonite and ultra-fine calcium carbonate in a ratio of 3:2:1) and the second mixture (vermiculite, expanded perlite and glass microbeads in a ratio of 2:2:1), so that the cementitious material forms a more stable microstructure. As can be seen from the SEM diagram of the hydration product, C-S-H and C(N)-A-S-H gel form a three-dimensional network, acicular ettringite crystals fill the pores, and the anchoring effect of the brucite phase significantly improves the mechanical properties of the material, such as strength and durability.

[0111] 2. As can be seen from Examples 1-5 and Comparative Examples 4-5, the pozzolanic activity of metakaolin in the first mixture and the Ca 2+ react to form more cementitious products, combined with the pore filling effect of ultra-fine calcium carbonate, significantly improving the material density; the water retention of bentonite reduces the shrinkage stress caused by water loss, combined with the elastic buffer structure formed by the lightweight aggregate in the second mixture, reducing the brittleness of the material while further inhibiting the generation of micro-cracks in low temperature environment, so that the wall maintains structural integrity during low temperature construction or use.

[0112] Comparative Example 6 (verify the synergistic effect of the components of the first mixture)

[0113] Raw materials: fly ash 30 parts, blast furnace slag 50 parts, lime 9 parts, desulfurization gypsum 3 parts, second mixture 5 parts, alkali activator 5 parts;

[0114] Adjustment: the first mixture is changed to single metakaolin (total amount remains 4 parts);

[0115] Purpose: to verify the synergistic effect of pozzolanic activity + pore filling + water retention in a ratio of 3:2:1 (Comparative Example 2);

[0116] The method for preparing the cementitious material is the same as in Example 1.

[0117] Mix the aged cementitious material slurry with the reinforcing fibers in a mass ratio of 100:3, stir uniformly, then pour into the mold, and cure at 80°C and a relative humidity of ≥90% for 48 hours, then demold, and cure under natural conditions for 28 days to obtain the fabricated wall.

[0118] Comparative Example 7 (verify the heat preservation structure of the second mixture)

[0119] Raw materials: fly ash 30 parts, blast furnace slag 50 parts, lime 9 parts, desulfurization gypsum 3 parts, first mixture 4 parts, alkali activator 5 parts;

[0120] Adjustment: the second mixture is changed to single expanded perlite (total amount remains 5 parts);

[0121] Purpose: to verify the continuous heat preservation barrier effect of the lightweight aggregate combination in a ratio of 2:2:1 (Comparative Example 2);

[0122] The preparation method of the cementitious material is the same as that in Example 1.

[0123] The aged cementitious material slurry and the reinforcing fibers are mixed at a mass ratio of 100:3, uniformly stirred, and then injected into a mold. The mold is cured at 80°C and a relative humidity of ≥90% for 48 hours, then demolded, and cured under natural conditions for 28 days to obtain the fabricated wall.

[0124] Comparative Example 8 (verification of low-temperature crack resistance)

[0125] The raw materials are the same as in Example 2, but the curing conditions are changed to 5°C and a relative humidity of 60% for 48 hours.

[0126] Test: loss rate of compressive strength and crack width after -20°C freeze-thaw cycles

[0127] Purpose: to verify the water retention of bentonite and the inhibitory effect of the buffer structure of lightweight aggregate on low-temperature cracking

[0128] The fabricated walls prepared in Examples 1-3 and Comparative Examples 6-8 are subjected to performance testing, and the test results are shown in Table 2:

[0129] Table 2:

[0130]

[0131] Conclusion:

[0132] 1. Comparing the data of Comparative Example 6 and Example 2 shows that:

[0133] Compressive strength (28d): 22.10 MPa (40.7% lower than Example 2);

[0134] Dry shrinkage rate: 0.048% (71.4% higher than Example 2);

[0135] Thermal conductivity: 0.25 W / m·K (66.7% higher than Example 2);

[0136] It can be seen that: Comparative Example 6 uses only a single metakaolin to replace the first mixture (metakaolin / bentonite / ultra-fine calcium carbonate 3:2:1), resulting in: decreased density: the pore filling effect of ultra-fine calcium carbonate is lacking, and the porosity of the gel product increases (SEM shows that the pore size increases); no bentonite is added, the water evaporation rate increases, the shrinkage stress increases, and microcracks are induced; early reaction is weakened: the absence of ion exchange capacity of bentonite delays the release rate of Ca 2+ and the hydration heat release peak is delayed (compare the heat release curves). Figure 3

[0137] ​2. Comparing the data of Comparative Example 7 and Example 2, it can be seen that:

[0138] Compressive strength (28d): 18.75 MPa (49.6% lower than Example 2);

[0139] Thermal conductivity: 0.30 W / m·K (100% higher than Example 2);

[0140] Frost resistance: only 150 freeze-thaw cycles (Example 2 ≥ 400 times);

[0141] It can be seen that: Comparative Example 7 only replaces the second mixture (vermiculite / pearlite / glass beads 2:2:1) with expanded perlite, resulting in: destruction of structural continuity: single perlite cannot form a multi-level pore barrier, increasing the heat conduction path; lack of the reinforcing effect of glass beads and the interlayer anchoring effect of vermiculite, the interfacial bonding force decreases (XRD shows that the crystallinity of the gel product decreases); the open pores increase, the water penetration intensifies, and the frost heaving stress concentrates.

[0142] 3. Comparing the data of Comparative Example 8 and Example 2, it can be seen that:

[0143] Performance: compressive strength (28d): 15.30 MPa (58.9% lower than Example 2)

[0144] Crack width: 0.55 mm (Example 2 has no visible cracks at -20°C)

[0145] Setting time: 180 min (Example 2 is 132 min)

[0146] It can be seen that: under the low temperature curing condition of 5°C, the low temperature of Comparative Example 8 delays the Ca 2+ / Na + synergistic excitation efficiency, and the gel network develops incompletely (FTIR shows that the Si-O-T bond absorption peak intensity is weakened); lack of the water retention buffering effect of the first mixture, water freezing and expansion leads to microcrack expansion (SEM shows that the cracks penetrate the gel phase); the ice of perlite pore water expands in volume at low temperature, destroying the aggregate-matrix interface

[0147] By comparing the data of Example 2 and Comparative Examples 6-8, the core innovation point of the patent technology is verified:

[0148] Synergistic effect of ternary components (first mixture): the strength loss of Comparative Example 6 confirms the synergistic effect of metakaolin (active Al source), bentonite (water retention), and ultra-fine calcium carbonate (filling);

[0149] Multi-stage insulation structure (second mixture): The thermal conductivity increase of Comparative Example 7 indicates that the combination of vermiculite (layered insulation), perlite (closed cell), and glass microsphere (reinforcement) is superior to a single aggregate;

[0150] Dual-alkali synergistic activation (Ca 2+ / Na + ): The low temperature performance degradation of Comparative Example 8 indicates that single Na + activation (NaOH) cannot maintain reactivity at low temperatures, while the Ca 2+ provided by patent lime (CaO) can promote low temperature hydration.

[0151] In the description of the present specification, the description referring to the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0152] The above shows and describes the basic principles, main features and advantages of the present application. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A cementitious material for preparing a fabricated wall body from poly-component solid waste, characterized in that, By weight parts comprising the following components: fly ash 25-55 parts, blast furnace slag 25-65 parts, lime 8-10 parts, desulfurization gypsum 1-5 parts, the first mixture 3-6 parts, the second mixture 2-5 parts, alkali activator 5-8 parts; the mass ratio of metakaolin, bentonite and superfine calcium carbonate in the first mixture is 3:2:1; the mass ratio of vermiculite, expanded perlite and glass beads in the second mixture is 2:2:1; the alkali activator is NaOH.

2. A method of producing a cementitious material for the production of a multi-element solid waste fabricated wall according to claim 1, characterised in that, Comprising the following steps: S1, raw material pretreatment: S1.1, the fly ash is classified, the particle size ≤45 μm fine powder and the particle size > 45 μm coarse powder are screened out by air flow classifier, the fine powder is used, and the coarse powder is used after air flow crushing to particle size ≤45 μm; S1.2, the blast furnace slag is treated by magnetic separation to remove iron, and then crushed to particle size ≤10 mm, and then air flow crushed to particle size ≤30 μm for standby; S1.3, the desulfurization gypsum is calcined at 150-180℃ for 2-3 hours to remove crystal water, and then ground to particle size ≤20 μm for standby; S1.4, the metakaolin is calcined at 800-850℃ for 1-2 hours, and then mixed with bentonite and superfine calcium carbonate according to the mass ratio of 3:2:1, put into a planetary ball mill, the ball to material ratio is 3:1, the rotating speed is 300r / min, and the ball milling time is 30-40 minutes to obtain the first mixture for standby; S1.5, the vermiculite is crushed to particle size 3-5mm, preheated at 300-400℃ for 1-1.5 hours; the expanded perlite is sieved to particle size 2-4mm; the glass beads are surface modified, soaked in silane coupling agent solution for 30-60 minutes, and then taken out and dried; then the treated vermiculite, expanded perlite and glass beads are mixed according to the mass ratio of 2:2:1 to obtain the second mixture for standby; S2, the pretreated fly ash, blast furnace slag, desulfurization gypsum, first mixture and second mixture are proportioned according to their chemical composition, weighed and put into a double-shaft paddle mixer, mixed at a rotating speed of 150-200r / min for 15-20 minutes, and then put into a vacuum oven, dried at 105±5℃ and a vacuum degree of-0.08 to-0.06MPa until the final moisture content is ≤1%; S3, stage ball milling treatment: S3.1, the dried fly ash and blast furnace slag are put into a ball mill, the ball to material ratio is 4:1, the rotating speed is 200r / min, and the ball milling time is 40-50 minutes to obtain the first stage mixed powder; S3.2, the lime and desulfurization gypsum are added to the first stage mixed powder, the ball to material ratio is 3:1, the rotating speed is 180r / min, and the ball milling time is 30-35 minutes to obtain the second stage mixed powder; S3.3, adding the first mixture and the second mixture to the second mixed powder, with a ball-to-material ratio of 2.5:1, a rotating speed of 150 r / min, and ball milling for 25-30 minutes to obtain the composite mineral powder, with a specific surface area of ≥450 m 2 / kg and a D50 controlled at 10-12 μm; S4, the industrial flake alkali NaOH is dissolved in deionized water to prepare a NaOH solution with a mass concentration of 30%-40%, and then placed for 24 hours; then the NaOH solution is slowly added to the composite mineral powder in proportion, and stirred at a speed of 80-100r / min for 15-20 minutes. S5, the mixture is put into a wet ball mill, with a ball-to-material ratio of 5:1, a rotation speed of 120 r / min, and ball milling for 60-90 minutes to obtain a slurry; the slurry is put into a sealed container and aged at 20-25℃ for 24-48 hours to obtain the cementitious material.

3. The method for preparing the cementitious material for the multi-element solid waste preparation fabricated wall body according to claim 2, characterized in that, The grinding balls of the planetary ball mill in step S1.4 are zirconia balls with diameters of 10 mm, 5 mm, and 3 mm, and the mass ratio of the three kinds of grinding balls is 2:2:

1.

4. The method for preparing the cementitious material for the multi-element solid waste preparation fabricated wall body according to claim 2, characterized in that, The silane coupling agent solution in step S1.5 is a 2%-3% KH-550 ethanol solution by mass fraction, and the volume ratio of ethanol to water is 9:

1.

5. The method for preparing the cementitious material for the multi-element solid waste preparation fabricated wall body according to claim 2, characterized in that, The amount of NaOH solution added in step S4 is 5%-8% of the total mass of the raw materials, calculated as Na2O.

6. The method for preparing the cementitious material for the multi-element solid waste preparation fabricated wall body according to claim 2, characterized in that, The medium for wet ball milling in step S5 is deionized water, and the solid-to-liquid ratio of the slurry is 1:1.2-1:1.

5.

7. Use of the cementitious material of claim 1 in the preparation of a fabricated wall.

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