Gypsum-based 3D printing mortar and preparation method thereof
阅读说明：本技术 一种石膏基3d打印砂浆及其制备方法 (Gypsum-based 3D printing mortar and preparation method thereof ) 是由 蒋旭峰 于 2020-05-18 设计创作，主要内容包括：一种石膏基3D打印砂浆及其制备方法,石膏基3D打印砂浆中循环流化床粉煤灰的重量份数为10～15份,石膏中SO-(3)的重量份数为15～22份,砂的重量份数为45～55份,氢氧化钙的重量份数为1～2份,微硅粉的重量份数为3～4份,水的重量份数为10～15份,还加入木质素纤维和分散剂。石膏基3D打印砂浆的制备方法,依次包括循环流化床粉煤灰粉磨预处理步骤、胶凝材料制备步骤、干粉料制备步骤和打印砂浆制备步骤。本发明充分利用工业废弃物循环流化床粉煤灰,减少其造成的环境负担,并且制备形成的3D打印砂浆性能优良。(10-15 parts of circulating fluidized bed fly ash in gypsum-based 3D printing mortar and SO in gypsum 3 15-22 parts of sand, 45-55 parts of calcium hydroxide, 3-4 parts of micro silicon powder and 10-15 parts of water, and lignin fiber and a dispersing agent are also added. The preparation method of the gypsum-based 3D printing mortar sequentially comprises a circulating fluidized bed fly ash grinding pretreatment step, a cementing material preparation step, a dry powder preparation step and a printing mortar preparation step. The invention fully utilizes the industrial waste circulating fluidized bed fly ash, reduces the environmental burden caused by the industrial waste circulating fluidized bed fly ash, and the prepared 3D printing mortar has excellent performance.)
1. The gypsum-based 3D printing mortar is characterized by comprising 10-15 parts by weight of circulating fluidized bed fly ash, 10-15 parts by weight of gypsum, sand, lignin fiber, calcium hydroxide, micro silicon powder, a dispersing agent and water3The sand is 15-22 parts by weight, the sand is 45-55 parts by weight, the calcium hydroxide is 1-2 parts by weight, the silica fume is 3-4 parts by weight, and the water is 10-15 parts by weight.
2. The gypsum-based 3D printing mortar of claim 1, further comprising borax in an amount of 0.01-0.03 parts by weight; the weight portion of the lignin fiber is 0.1-0.2, and the weight portion of the dispersing agent is 0.01-0.05.
3. The gypsum-based 3D printing mortar of claim 1, wherein the gypsum comprises desulfurized gypsum and natural gypsum, SO in the desulfurized gypsum and the natural gypsum3The mass fraction of the natural gypsum is more than 50%, the weight fraction of the desulfurized gypsum is 15-20 parts, and the weight fraction of the natural gypsum is 10-15 parts.
4. The gypsum-based 3D printing mortar of claim 3, wherein the desulfurized gypsum has a water content of less than 10%; the specific surface area of the natural gypsum is 400-500 m2/kg。
5. The gypsum-based 3D printing mortar of claim 1, wherein the circulating fluidized bed fly ash has a specific surface area of 500-600 m2Per kg; the fineness of the sand is 40-70 meshes; SiO in the micro silicon powder2The content of (A) is more than 90%, and the specific surface area of the micro silicon powder is 15000-20000 m2Per kg; the length of the lignin fiber is less than 6mm, and the ash content is less than 15%; the dispersing agent is a low-concentration naphthalene water reducer, and the water reducing rate of the dispersing agent is more than 15%.
6. The preparation method of the gypsum-based 3D printing mortar is characterized by comprising the following steps:
s1 pretreatment: grinding the circulating fluidized bed fly ash;
s2 preparation of the cementing material: mixing and stirring the pulverized circulating fluidized bed fly ash, gypsum, calcium hydroxide and micro silicon powder uniformly to obtain a cementing material, wherein the weight fraction of the fluidized bed fly ash is 10-15 parts, and SO in the gypsum is313-18 parts of calcium hydroxide, 1-2 parts of calcium hydroxide and 3-4 parts of silica fume;
s3 preparation of dry powder: adding 45-55 parts of sand into the cementing material, mixing, adding lignin fiber and a dispersing agent, and uniformly stirring to obtain a dry powder of the printing mortar;
s4 preparation of printing mortar: adding water into the printing mortar dry powder and uniformly stirring, wherein the weight part of the water is 10-15, so as to prepare the gypsum-based 3D printing mortar.
7. The preparation method of the gypsum-based 3D printing mortar according to claim 6, wherein borax is further added in step S3, the borax is added together with the lignin fibers and the dispersing agent, and the weight portion of the borax is 0.01-0.03 portion; the weight portion of the lignin fiber is 0.1-0.2, and the weight portion of the dispersing agent is 0.01-0.05.
8. The preparation method of the gypsum-based 3D printing mortar according to claim 6, wherein the gypsum in the S2 prepared cementing material comprises desulfurized gypsum and natural gypsum, and SO in the desulfurized gypsum3The natural gypsum contains more than 50% of water, the water content is less than 10%, the weight portion of the desulfurized gypsum is 15-20 parts, and SO in the natural gypsum3Has a mass fraction of 50% or more and a specific surface area of 400 to 500m2And/kg, wherein the weight part of the natural gypsum is 10-15 parts.
9. The method of preparing a gypsum-based 3D printing mortar according to claim 6,
the fly ash of the circulating fluidized bed is ground until the specific surface area is 500-600 m2Per kg; the fineness of the sand is 40-70 meshes; SiO in the micro silicon powder2The content of (A) is more than 90%, and the specific surface area of the micro silicon powder is 15000-20000 m2Per kg; the length of the lignin fiber is less than 6mm, and the ash content is less than 15%; the dispersing agent is a low-concentration naphthalene water reducer, and the water reducing rate of the dispersing agent is more than 15%.
10. The method for preparing the gypsum-based 3D printing mortar according to claim 6, wherein the reaction formula involved in step S4 is:
CaO+H2O＝Ca(OH)2；
CaSO4+H2O＝CaSO4·2H2O；
SiO2+xCa(OH)2+H2O＝xCaO·SiO2·H2O；
A12O3+yCa(OH)2+H2O＝yCaO·A12O3·H2O；
yCaO·A12O3·H2O+CaSO4·2H2O+H2O＝zCaO·A12O3·CaSO4·H2O。
Technical Field
The invention relates to the technical field of building material engineering, in particular to gypsum-based 3D printing mortar and a preparation method thereof.
Background
With the further enhancement of the environmental protection requirements, the comprehensive utilization of various industrial wastes has attracted extensive attention. The high-quality fly ash and mineral powder are widely applied in the cement concrete industry and become scarce resources.
The fly ash of the circulating fluidized bed is different from the common fly ash in chemical composition, mineral composition and performance, and has coarse particles, irregular appearance, f-CaO and SO3High content, and the main mineral composition of anhydrite and lime, and the like, and most of the anhydrite and the lime do not meet the prior technical standard and use specification, so the anhydrite and the lime are difficult to be directly applied to cement concrete. Thus, circulating fluidized bed fly ash utilization has been low, which still places a heavy burden on the environment.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a method for preparing gypsum-based 3D printing mortar by effectively utilizing industrial waste circulating fluidized bed fly ash and a prepared gypsum-based 3D printing mortar material.
In order to achieve the purpose, the invention adopts the following technical scheme:
the gypsum-based 3D printing mortar comprises 10-15 parts by weight of circulating fluidized bed fly ash, 10-15 parts by weight of gypsum, sand, lignin fiber, calcium hydroxide, micro silicon powder, a dispersing agent and water3The sand is 15-22 parts by weight, the sand is 45-55 parts by weight, the calcium hydroxide is 1-2 parts by weight, the silica fume is 3-4 parts by weight, and the water is 10-15 parts by weight.
Preferably, the paint also comprises borax, wherein the weight part of the borax is 0.01-0.03 part; the weight portion of the lignin fiber is 0.1-0.2, and the weight portion of the dispersing agent is 0.01-0.05.
Preferably, the gypsum comprises desulfurized gypsum and natural gypsum, and SO in the desulfurized gypsum and the natural gypsum3The mass fraction of the natural gypsum is more than 50%, the weight fraction of the desulfurized gypsum is 15-20 parts, and the weight fraction of the natural gypsum is 10-15 parts.
Preferably, the water content of the desulfurized gypsum is lower than 10%; the specific surface area of the natural gypsum is 400-500 m2/kg。
Preferably, the specific surface area of the fly ash of the circulating fluidized bed is 500-600 m2Per kg; the fineness of the sand is 40-70 meshes; SiO in the micro silicon powder2Is more than 90 percent, the micro siliconThe specific surface area of the powder is 15000-20000 m2/kg。
Preferably, the length of the lignin fiber is less than 6mm, and the ash content is less than 15%; the dispersing agent is a low-concentration naphthalene water reducer, and the water reducing rate of the dispersing agent is more than 15%.
A preparation method of gypsum-based 3D printing mortar comprises the following steps:
s1 pretreatment: grinding the circulating fluidized bed fly ash;
s2 preparation of the cementing material: mixing and stirring the pulverized circulating fluidized bed fly ash, gypsum, calcium hydroxide and micro silicon powder uniformly to obtain a cementing material, wherein the weight fraction of the fluidized bed fly ash is 10-15 parts, and SO in the gypsum is313-18 parts of calcium hydroxide, 1-2 parts of calcium hydroxide and 3-4 parts of silica fume;
s3 preparation of dry powder: adding 45-55 parts of sand into the cementing material, mixing, adding lignin fiber and a dispersing agent, and uniformly stirring to obtain a dry powder of the printing mortar;
s4 preparation of printing mortar: adding water into the printing mortar dry powder and uniformly stirring, wherein the weight part of the water is 10-15, so as to prepare the gypsum-based 3D printing mortar.
Preferably, borax is also added in the step S3, the borax, the lignin fiber and the dispersant are added together, and the weight part of the borax is 0.01-0.03; the weight portion of the lignin fiber is 0.1-0.2, and the weight portion of the dispersing agent is 0.01-0.05.
Preferably, the gypsum in the S2-prepared cementing material comprises desulfurized gypsum and natural gypsum, and SO in the desulfurized gypsum3The natural gypsum contains more than 50% of water, the water content is less than 10%, the weight portion of the desulfurized gypsum is 15-20 parts, and SO in the natural gypsum3Has a mass fraction of 50% or more and a specific surface area of 400 to 500m2And/kg, wherein the weight part of the natural gypsum is 10-15 parts.
Preferably, the fly ash of the circulating fluidized bed is ground until the specific surface area is 500-600 m2Per kg; what is needed isThe fineness of the sand is 40-70 meshes; SiO in the micro silicon powder2The content of (A) is more than 90%, and the specific surface area of the micro silicon powder is 15000-20000 m2Per kg; the length of the lignin fiber is less than 6mm, and the ash content is less than 15%; the dispersing agent is a low-concentration naphthalene water reducer, and the water reducing rate of the dispersing agent is more than 15%.
Preferably, the reaction formula involved in step S4 is:
CaO+H2O＝Ca(OH)2；
CaSO4+H2O＝CaSO4·2H2O；
SiO2+xCa(OH)2+H2O＝xCaO·SiO2·H2O；
A12O3+yCa(OH)2+H2O＝yCaO·A12O3·H2O；
yCaO·A12O3·H2O+CaSO4·2H2O+H2O＝zCaO·A12O3·CaSO4·H2O。
according to the gypsum-based 3D printing mortar and the preparation method thereof, the industrial waste circulating fluidized bed fly ash is fully utilized, the problem of recycling of part of desulfurized gypsum is solved, and the gypsum-based 3D printing mortar is prepared and formed. The recycling rate of the industrial waste circulating fluidized bed fly ash is improved, the environmental burden caused by the industrial waste circulating fluidized bed fly ash is reduced, and the prepared 3D printing mortar is high in strength, strong in water resistance, good in heat preservation and sound insulation effects and widely applicable to the building industry.
Detailed Description
The concrete implementation of the gypsum-based 3D printing mortar and the preparation method thereof according to the present invention will be further described with reference to the given examples. The gypsum-based 3D printing mortar and the method for preparing the same according to the present invention are not limited to the description of the following examples.
Example one
The embodiment provides a preparation method of gypsum-based 3D printing mortar, which comprises the following steps:
s1 pretreatment: and (3) grinding the circulating fluidized bed coal ash, preferably grinding until the specific surface area is 500-600 square meters per kg.
The fly ash of the circulating fluidized bed is the fly ash collected in the flue of the circulating fluidized bed boiler, the particles of the fly ash of the circulating fluidized bed are coarse, irregular particles are taken as main particles, and f-CaO and SO are added3High content, and because it adopts calcium spraying desulfurization method, it contains lots of unreacted desulfurizer lime and desulfurization product anhydrite in the circulating fluidized bed flyash. The circulating fluidized bed fly ash is ground to the specific surface area of 500-600 square meters per kilogram, the higher the specific surface area of the circulating fluidized bed fly ash is, the higher the reaction activity is, and the circulating fluidized bed fly ash is ground to the specific surface area, so that f-CaO particles contained in the circulating fluidized bed fly ash are easy to react with water in the later-stage mortar preparation process, and the adverse effect of f-CaO on the stability of the mortar and a building formed by printing is eliminated. The grinding can be performed in various modes such as a vertical mill, a tubular mill, a roller press and the like, and the grinding mode is not limited.
S2 preparation of the cementing material: mixing and stirring the pulverized circulating fluidized bed fly ash, gypsum, calcium hydroxide and micro-silicon powder uniformly to obtain a gel material, wherein the circulating fluidized bed fly ash is 12 parts by weight, and SO is contained in the gypsum3The weight portion of the calcium hydroxide is 15 portions, the weight portion of the calcium hydroxide is 1 portion, and the weight portion of the silica fume is 3 portions.
In order to further improve the utilization rate of industrial wastes and reduce the cost of preparing the 3D printing mortar by the method, the gypsum in the step can be a mixture of industrial waste desulfurized gypsum and natural gypsum, the desulfurized gypsum contains a certain amount of calcium sulfite hemihydrate and other impurities, and the addition of the desulfurized gypsum can influence the setting time and the early strength of the mortar, SO that the quality of the desulfurized gypsum can be effectively ensured by controlling the addition amount of the desulfurized gypsum and the content of effective components of the desulfurized gypsum3The content of the sulfur-free gypsum is used for representing the quality of the sulfur-free gypsum, and in addition, the water content of the sulfur-free gypsum also influences the blanking difficulty degree in the mortar preparation process. The natural gypsum has good quality but higher cost, and needs to be ground into powder with higher specific surface area so as to have higher reaction activity. Therefore, the temperature of the molten metal is controlled,SO in desulfurized Gypsum in this example3The mass fraction of the gypsum is required to be more than 50%, the water content is less than 10%, the weight fraction of the desulfurized gypsum is 15-20 parts, and SO in the natural gypsum3The mass fraction of (A) is required to be more than 50%, and the specific surface area is 400-500 m2And per kg, the weight part of the natural gypsum is 10-15 parts. Specifically, SO in the desulfurized gypsum used in this example3The content of (1) is 60 percent, the weight portion is 15 portions, SO in the natural gypsum3The content of (B) is 60%, and the weight portion is 10 portions.
SiO in micro silicon powder2The content of (A) is more than 90%, and the specific surface area of the micro silicon powder is 15000-20000 m2And/kg, the micro silicon powder is high-activity superfine powder, is used as a raw material and added into the preparation process of the mortar, has a micro filling effect, and is beneficial to improving the strength of the mortar.
S3 preparation of dry powder: adding sand into the gelled material, mixing, adding borax, lignin fiber and a dispersing agent, and uniformly stirring to prepare the dry powder of the printing mortar, wherein the weight parts of the sand is 52, the weight parts of the borax is 0.01, the weight parts of the lignin fiber is 0.1, and the weight parts of the dispersing agent is 0.02.
The sand in the embodiment is a main source of the strength of the mortar, and fine sand or medium sand with the fineness of 40-70 meshes is adopted. The borax is used as a retarder and can reduce the hydration speed and the hydration heat of cement or gypsum, so that the setting time of the mortar is prolonged, and the mortar is more suitable for being used in 3D printing equipment. The length of the lignin fiber is less than 6mm, the ash content is less than 15%, and the lignin fiber is used as a stabilizer in the printing mortar to improve the thickening and anti-cracking performance of the printing mortar. The dispersing agent is a water reducing agent, preferably a low-concentration naphthalene water reducing agent, the water reducing rate of the dispersing agent is more than 15%, the naphthalene water reducing agent is a chemically synthesized non-air-entraining high-efficiency water reducing agent, particularly a naphthalene sulfonate formaldehyde condensation compound, and the naphthalene water reducing agent has a strong dispersing effect, improves the fluidity of slurry, facilitates the slurry to flow in a pipeline of a 3D printer, and can effectively improve the mechanical property of mortar.
S4 preparation of printing mortar: adding water into the printing mortar dry powder, uniformly stirring, wherein the weight part of the water is 10 parts, preparing the gypsum-based 3D printing mortar, and adding the gypsum-based 3D printing mortar into printing equipment to perform printing operation.
In the step, the natural gypsum particles and the desulfurized gypsum particles are combined with water to form a dihydrate gypsum structure, and the dihydrate gypsum structure can be quickly hardened in the drying process after printing, so that the printed material has strength.
Meanwhile, after water is added, SiO in the fly ash of the circulating fluidized bed2、Al2O3And SiO in the microsilica2Reacts with the gypsum, the calcium hydroxide and CaO contained in the circulating fluidized bed fly ash to generate hydrated calcium sulphoaluminate and C-S-H gel, and the hydrated calcium sulphoaluminate and the C-S-H gel have higher early strength and a certain amplitude of later strength increase, thereby providing strength for the mortar. In addition, in the drying process after printing, hydrated calcium sulphoaluminate and dihydrate gypsum can jointly form hardened slurry, so that the solidification speed and the early strength of the prepared mortar are improved, the application in 3D printing equipment is facilitated, and the reaction formula generated by the hydrated calcium sulphoaluminate, C-S-H gel and the hardened slurry is as follows:
CaO+H2O＝Ca(OH)2；
CaSO4+H2O＝CaSO4·2H2O；
SiO2+xCa(OH)2+H2O＝xCaO·SiO2·H2O；
A12O3+yCa(OH)2+H2O＝yCaO·A12O3·H2O；
yCaO·A12O3·H2O+CaSO4·2H2O+H2O＝zCaO·A12O3·CaSO4·H2O
the 3D printing mortar is prepared and formed by adopting the method, wherein the circulating fluidized bed fly ash accounts for 12 parts by weight, and SO is contained in gypsum315 parts of sand, 52 parts of calcium hydroxide, 3 parts of silica fume, 0.01 part of borax, 0.1 part of lignin fiber and 0.02 part of dispersant,the weight portion of the water is 10 portions.
Adding the prepared printing mortar into a 3D printer to perform printing operation, wherein the parameters of the printer are set as follows: the walking speed is 0.5 m/s, the printing layer thickness is 1.2cm, and the blank after printing is kept stand and naturally cured. And cutting the cured blank, and testing the strength of the blank to obtain the compressive strength of 34.3 MPa.
Example two
The embodiment provides a preparation method of gypsum-based 3D printing mortar, which comprises the following steps:
s1 pretreatment: and (3) grinding the circulating fluidized bed coal ash, preferably grinding until the specific surface area is 500-600 square meters per kg.
S2 preparation of the cementing material: mixing and stirring the pulverized circulating fluidized bed fly ash, desulfurized gypsum, natural gypsum, calcium hydroxide and micro-silicon powder uniformly to obtain a gel material, wherein the weight part of the circulating fluidized bed fly ash is 14 parts, and SO in the desulfurized gypsum is3Is 55 percent, 20 parts by weight, SO in the natural gypsum3The content of (1) is 60 percent, the weight portion is 15 portions, the weight portion of calcium hydroxide is 2 portions, and the micro silicon powder SiO is2The content of (A) is more than 90%, and the specific surface area is 15000-20000 m2Per kg, 4 parts by weight.
S3 preparation of dry powder: and adding sand into the cementing material, mixing, adding borax, lignin fiber and a dispersing agent, and uniformly stirring to prepare the dry powder of the printing mortar. Wherein the fineness of the sand is 40-70 meshes, and the weight portion of the sand is 46 portions; 0.02 part of borax; the length of the lignin fiber is less than 6mm, the ash content is less than 15 percent, and the weight portion is 0.1 portion; the dispersant is a low-concentration naphthalene water reducer, the water reducing rate is 15%, and the weight portion is 0.02 portion.
S4 preparation of printing mortar: adding water into the printing mortar dry powder, uniformly stirring, wherein the weight part of the water is 14, preparing the gypsum-based 3D printing mortar, and adding the gypsum-based 3D printing mortar into printing equipment to perform printing operation.
The 3D printing mortar is prepared and formed by adopting the method, wherein the circulating fluidized bed fly ash accounts for 14 parts by weight, and SO is contained in gypsum3In parts by weight ofThe weight portion of the active carbon is 20 portions, the weight portion of the sand is 46 portions, the weight portion of the calcium hydroxide is 2 portions, the weight portion of the silica fume is 4 portions, the weight portion of the borax is 0.02 portion, the weight portion of the lignin fiber is 0.1 portion, the weight portion of the dispersing agent is 0.02 portion, and the weight portion of the water is 14 portions.
Adding the prepared printing mortar into a 3D printer to perform printing operation, wherein the parameters of the printer are set as follows: the walking speed is 0.5 m/s, the printing layer thickness is 1.2cm, and the blank after printing is kept stand and naturally cured. And cutting the cured blank, and testing the strength of the blank to obtain the compressive strength of 35.1 MPa.
EXAMPLE III
The embodiment provides a preparation method of gypsum-based 3D printing mortar, which comprises the following steps:
s1 pretreatment: and (3) grinding the circulating fluidized bed coal ash, preferably grinding until the specific surface area is 500-600 square meters per kg.
S2 preparation of the cementing material: mixing and stirring the pulverized circulating fluidized bed fly ash, desulfurized gypsum, natural gypsum, calcium hydroxide and micro-silica powder uniformly to prepare a gel material, wherein the weight part of the circulating fluidized bed fly ash is 10 parts, and SO in the desulfurized gypsum is3Is 50 percent, 18 parts by weight, SO in the natural gypsum355 percent of calcium hydroxide, 12 parts of calcium hydroxide, 1.5 parts of silica fume SiO2The content of (A) is more than 90%, and the specific surface area is 15000-20000 m2Per kg, 3.5 parts by weight.
S3 preparation of dry powder: and adding sand into the gelled material, mixing, adding the lignin fiber and the dispersing agent, and uniformly stirring to obtain the dry powder of the printing mortar. Wherein the fineness of the sand is 40-70 meshes, and the weight portion is 45 portions; the length of the lignin fiber is less than 6mm, the ash content is less than 15 percent, and the weight portion is 0.15 portion; the dispersant is a low-concentration naphthalene water reducer, the water reducing rate is 15%, and the weight portion is 0.01 portion.
S4 preparation of printing mortar: adding water into the printing mortar dry powder, uniformly stirring, wherein the weight part of the water is 11 parts, preparing the gypsum-based 3D printing mortar, and adding the gypsum-based 3D printing mortar into printing equipment to perform printing operation.
The 3D printing mortar is prepared and formed by adopting the method, wherein the circulating fluidized bed fly ash accounts for 10 parts by weight, and SO is contained in gypsum315.6 parts of sand, 45 parts of calcium hydroxide, 3.5 parts of micro silicon powder, 0.15 part of lignin fiber, 0.01 part of dispersant and 11 parts of water.
Adding the prepared printing mortar into a 3D printer to perform printing operation, wherein the parameters of the printer are set as follows: the walking speed is 0.5 m/s, the printing layer thickness is 1.2cm, and the blank after printing is kept stand and naturally cured. And cutting the cured blank, and testing the strength of the blank to obtain the compressive strength of 32.9 MPa.
Example four
S1 pretreatment: and (3) grinding the circulating fluidized bed coal ash, preferably grinding until the specific surface area is 500-600 square meters per kg.
S2 preparation of the cementing material: mixing and stirring the pulverized circulating fluidized bed fly ash, desulfurized gypsum, natural gypsum, calcium hydroxide and micro-silica powder uniformly to obtain a gel material, wherein the weight part of the circulating fluidized bed fly ash is 15 parts, and SO in the desulfurized gypsum is3The content of (1) is 65 percent, the weight portion is 20 portions, SO in the natural gypsum3The content of (1) is 60 percent, the weight portion is 15 portions, the weight portion of calcium hydroxide is 2 portions, and the micro silicon powder SiO is2The content of (A) is more than 90%, and the specific surface area is 15000-20000 m2Per kg, 4 parts by weight.
S3 preparation of dry powder: and adding sand into the cementing material, mixing, adding borax, lignin fiber and a dispersing agent, and uniformly stirring to prepare the dry powder of the printing mortar. Wherein the fineness of the sand is 40-70 meshes, and the weight portion is 55 portions; 0.03 part of borax; the length of the lignin fiber is less than 6mm, the ash content is less than 15 percent, and the weight portion is 0.2 portion; the dispersant is a low-concentration naphthalene water reducer, the water reducing rate is 15%, and the weight portion is 0.05 portion.
S4 preparation of printing mortar: adding water into the printing mortar dry powder, uniformly stirring, wherein the weight part of the water is 15 parts, preparing the gypsum-based 3D printing mortar, and adding the gypsum-based 3D printing mortar into printing equipment to perform printing operation.
The 3D printing mortar is prepared and formed by adopting the method, wherein the circulating fluidized bed fly ash accounts for 15 parts by weight, and SO is contained in gypsum3The weight portion of the composite material is 22 parts, the weight portion of the sand is 55 parts, the weight portion of the calcium hydroxide is 2 parts, the weight portion of the silica fume is 4 parts, the weight portion of the borax is 0.03 part, the weight portion of the lignin fiber is 0.2 part, the weight portion of the dispersing agent is 0.05 part, and the weight portion of the water is 15 parts.
Adding the prepared printing mortar into a 3D printer to perform printing operation, wherein the parameters of the printer are set as follows: the walking speed is 0.5 m/s, the printing layer thickness is 1.2cm, and the blank after printing is kept stand and naturally cured. And cutting the cured blank, and testing the strength of the blank to obtain the compressive strength of 35.8 MPa.
The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.