Coagulation regulation and control material for two-component 3D printing mortar and preparation method of coagulation regulation and control material

Abstract

The invention discloses a condensation regulation and control material for two-component 3D printing mortar and a preparation method of the condensation regulation and control material. The material comprises a component A and a component B, the component A comprises the following components in parts by weight: 40-44% of ordinary Portland cement; 41%-47% of sand; 12%-14% of mixing water; 0.8% to 0.88% of a retarder; 0.4%-0.44% of a water reducing agent; the component B comprises the following components in parts by weight: 20-25% of a coagulant; 0.2%-0.4% of a viscosity modifier; 44%-50% of a powdery carrier; and 25%-30% of mixing water. According to the invention, the component A has a longer window period and longer setting time, and the used materials are convenient and can be obtained locally; the component B is convenient to use, powder materials are directly mixed and placed before mixing, water is added for mixing when the component B is used, the stability is good, and the layering phenomenon cannot be generated after the component B is placed for a long time; after the component A and the component B are mixed, the early strength development is faster, the constructability is higher, and the later strength shrinkage phenomenon is less.

Description

Technical Field

[0001] The present invention relates to a 3D printing cement-based material and a preparation method thereof, and particularly to a setting control material for a two-component 3D printing mortar and a preparation method thereof. Background Art

[0002] 3D printing technology is an advanced manufacturing technology that accumulates materials and constructs entities by using computer-aided design data. With the leap of the technological level of human society, as one of the key technologies for the transformation of modern industry from informatization to intelligence, 3D printing is widely used in many fields such as metal processing, automobiles, medical devices, and aerospace. 3D printing construction technology is a new intelligent manufacturing technology that combines 3D printing technology with concrete material technology. Its main advantages lie in automation, personalization, and formwork removal. The particularity of 3D printing construction technology makes it have broad application prospects in reducing construction costs, improving productivity, maintaining environmental friendliness, and reducing safety hazards caused by the use of manpower.

[0003] Currently, the relatively mature 3D printing construction technology is a process in which a print head used by a robotic arm or a gantry structure deposits materials on a predefined path, directly extrudes them through a nozzle, and stacks the materials layer by layer using gravity and the compaction effect of the nozzle to form a structure. In the whole process, the material often enters the print head directly after being mixed once, which is also called single-component 3D printing. During the pumping process, the material needs to have a low dynamic yield stress and viscosity, while during the printing construction process, it is required that the material has a high static yield stress and a high yield strength growth rate to resist plastic failure and elastic buckling failure caused by its own gravity. This makes the typical 3D printing construction technology have high requirements for materials, and general cement-based materials cannot be used as 3D printing materials. In order to pursue the printing effect, 3D printing construction often needs to use high-grade cement or rapid-hardening cement such as sulfoaluminate cement, and at the same time add nano-clay and silica fume to improve the thixotropy of the material, which makes the cost of this technology relatively expensive. In addition, due to certain requirements for the fluidity of the material in the pumping stage, in single-component 3D printing, the material sacrifices the performance requirement of rapid setting in order to extend the pumping window period. Therefore, the vertical stacking performance of single-component 3D printing is poor, the vertical construction rate is low, and the construction period is long. At the same time, single-component 3D printing materials cannot realize the premixed production of a concrete mixing plant, and often need to be mixed on the construction site. After mixing, pumping and printing must be completed within the initial setting time, otherwise the pumping equipment and 3D printers will be damaged, which makes this technology have high requirements for personnel organization and construction management at the construction site.

[0004] Therefore, it is very important to develop a setting control material based on two-component 3D printing mortar that is applicable to pumping, has a long window period, good stability, and can quickly coagulate and harden after mixing, which is of great significance for promoting the development and popularization of 3D printing construction technology. Summary of the Invention

[0005] Object of the Invention: The object of the present invention is to provide a setting control material for two-component 3D printing mortar that is applicable to pumping, has a long window period, good stability, and can quickly coagulate and harden after mixing;

[0006] The second object of the present invention is to provide a preparation method of the above-mentioned setting control material for two-component 3D printing mortar.

[0007] Technical Solution: The setting control material for two-component 3D printing mortar described in the present invention includes component A and component B;

[0008] The mass percentages of the raw materials in component A are as follows:

[0009]

[0010] The mass percentages of the raw materials in component B are as follows:

[0011]

[0012] Among them, the coagulant is aluminum sulfate octadecahydrate.

[0013] Among them, the viscosity modifier is anionic polyacrylamide; its molecular weight is 18 million - 30 million.

[0014] Among them, the powdery carrier is quartz powder, and the particle size of the quartz powder is 300 - 400 mesh.

[0015] Among them, the retarder is sodium gluconate.

[0016] Among them, the water reducer is a polycarboxylate high-performance powdery water reducer, and its water reduction rate is greater than 40%.

[0017] Among them, the sand particle size range is 0.18 mm - 4.75 mm, and the fineness modulus is 1.8 - 3.5.

[0018] The preparation method of the above-mentioned setting control material for two-component 3D printing mortar includes the following steps:

[0019] (1) Weigh the cementitious material, sand, mixing water, retarder, and water reducer in proportion, mix them, and then add mixing water to obtain component A;

[0020] (2) Weigh the coagulant promoter, viscosity modifier, powdered carrier, and mixing water proportionally, and obtain Component B after mixing.

[0021] (3) Pump Component A and Component B into a two-component 3D printing head respectively, mix them and then extrude to obtain the setting control material for two-component 3D printing mortar.

[0022] Among them, in step (1), mix at a speed of 15 - 30 r / min for 3 - 5 min to obtain Component A.

[0023] Among them, in step (2), mix at a speed of 15 - 30 r / min for 5 - 10 min to obtain Component B.

[0024] In step (2), first mix the coagulant promoter, viscosity modifier and powdered carrier, and then add the mixing water when in use.

[0025] Among them, in step (3), the pumping flow rate of Component A is 6 - 8 L / min; the pumping flow rate of Component B is 0.6 - 0.8 L / min.

[0026] Among them, in step (3), pump Component A and Component B into the two-component 3D printing head through a mortar pump and a cam rotor pump respectively according to a volume ratio of 8 - 12:1, mix them and then extrude after 10 - 20 s to obtain the setting control material for two-component 3D printing mortar.

[0027] For the Component A of the present invention, the initial flow table fluidity is at least greater than 280 mm, and the initial setting time is greater than 4 hours; after Component A and Component B are mixed evenly, the initial flow table fluidity is greater than 180 mm. After Component A and Component B are mixed, the initial setting time is less than 20 min.

[0028] The 3D printing nozzle is a circular nozzle with a diameter of 50 mm.

[0029] During 3D printing, the 3D printing layer thickness is 20 mm, the horizontal printing speed is 10 m / min, and the single continuous printing height is 0.5 - 1 m.

[0030] Principle of the invention: The viscosity modifier used in the present invention is a macromolecular substance, and its long molecular chain can "entangle" with substances in the system and absorb a certain amount of water at the same time. This reaction is a physical effect with an extremely short action time and good effect. The main purpose is to quickly increase the overall viscosity when components A and B are just mixed, so that the system has certain buildability just after mixing. The sulfate radical and aluminum ion contained in the quick-setting agent used in the present invention can optimize the calcium-aluminum-sulfur balance inside the material system during the initial stage of the hydration reaction, quickly form a large number of ettringite crystals, and rapidly increase the solid content in the system to fill the voids, so that the system has a high yield strength growth rate for a period of time after components A and B are mixed. This reaction is a chemical effect and requires a certain reaction time. The main purpose is to enable the buildability to develop rapidly to support its own gravity and subsequent layer weights and resist damage after components A and B are mixed and extruded.

[0031] The present invention uses quartz powder to convert component B from a commonly used liquid into a slurry. Component B in the two-component 3D printing cement-based slurry in the prior art is usually a liquid, and its existing defects are as follows: on the one hand, when mixed with component A, it will introduce excess water into component A that is already pumpable and stable, thus changing the water-cement ratio of the composition. While the change in the water-cement ratio will have a huge impact on the strength, it will also affect the use effect of the water reducer sensitive to water; on the other hand, the dosage of the liquid is often small, and stirring in the 3D printing head will cause uneven stirring. However, the present invention introduces quartz powder as a powder carrier in component B. When it is necessary to mix with component A, only the remaining several components in component B need to be added to the quartz powder to form a slurry, thus overcoming the influence of the liquid component B.

[0032] Beneficial effects: Compared with the prior art, the present invention has the following remarkable effects:

[0033] Component A of the present invention has a longer window period and a longer setting time, and the materials are convenient to use and can be obtained locally; component B is convenient to use. The powder materials can be directly mixed and placed before mixing, and directly mixed with water when in use. It has good stability and will not produce layering phenomenon after being placed for a long time; after components A and B are mixed, the strength develops faster in the early stage, the buildability is higher, and the phenomenon of strength retrogression in the later stage is less. Description of the drawings

[0034] Figure 1 Comparison of the effects of different materials used on the development of early yield stress;

[0035] Figure 2 Time-dependent change diagram of the fluidity of component A under different water reducer dosages in Comparative Example 4;

[0036] Figure 3 Change diagram of the setting time of component A under different water reducer dosages in Comparative Example 4;

[0037] Figure 4 The graph of the change in fluidity of Component A over time with different retarding agent dosages in Comparative Example 5;

[0038] Figure 5 The graph of the change in setting time of Component A with different retarding agent dosages in Comparative Example 5;

[0039] Figure 6 The graph of the change in fluidity and slump of the components obtained by compounding anionic polyacrylamide, calcium nitrate, and aluminum sulfate with cement respectively in Comparative Example 1 with the change in dosage;

[0040] Figure 7 The graph of the change in fluidity and slump of the components obtained in Comparative Examples 2 and 3 with the change in dosage;

[0041] Figure 8 The change over time in slump and fluidity of the components obtained by compounding anionic polyacrylamide, calcium nitrate, and aluminum sulfate with cement respectively in Comparative Example 1;

[0042] Figure 9 The graph of the change in fluidity and slump of the components obtained in Comparative Examples 2 and 3 with the change in dosage;

[0043] Figure 10 The change in yield strength in the first 1 h of the single - admixture group and the compound - admixture group in the penetration resistance experiment;

[0044] Figure 11 The change in yield strength in the first 10 min of the single - admixture group and the compound - admixture group in the penetration resistance experiment;

[0045] Figure 12 The change in yield strength of the aluminum sulfate group under different dosages and conditions of whether the mixture is uniform;

[0046] Figure 13 The compressive property graphs of the components obtained in Comparative Examples 2 and 3 at 3 days, 7 days, 28 days, and 56 days;

[0047] Figure 14 The compressive property graphs of the components obtained in Comparative Example 3 under two conditions of printing and pouring at 3 days, 7 days, 28 days, and 56 days;

[0048] Figure 15 The flexural property graphs of the components obtained in Comparative Examples 2 and 3 at 3 days, 7 days, 28 days, and 56 days;

[0049] Figure 16 The compressive property graphs of the components obtained in Comparative Example 3 under two conditions of printing and pouring at 3 days, 7 days, 28 days, and 56 days. Detailed implementation mode

[0050] The present invention will be further described in detail below.

[0051] Example 1

[0052] A two-component 3D printing mortar setting regulating material comprises component A and component B; the mass percentages of the raw materials of component A are as follows: 42.9% of ordinary Portland cement, 42.9% of sand, 13% of mixing water, retarder: 0.8% of sodium gluconate, water reducer: 0.4% of polycarboxylic acid high-performance powdered water reducer; the particle size range of the sand is 0.18 mm to 4.75 mm, and the fineness modulus is 1.8 to 3.5; the mass percentages of the raw materials of component B are as follows: accelerator: 21% of aluminum sulfate 18hydrate, viscosity modifier: 0.3% of anionic polyacrylamide, powdered carrier: 49% of quartz powder, and 29.7% of mixing water.

[0053] The method for preparing the above-mentioned coagulation regulating material of the two-component 3D printing mortar comprises the following steps:

[0054] (1) Preparation of Component A: Stir the raw material powders in Component A in advance, then add water and stir thoroughly.

[0055] Component A can be pre-mixed at the mixing station and then loaded into a concrete mixer truck for transportation to the construction site, or it can be mixed on site and then pumped into a two-component 3D printer for use. The amount of each mix should be reasonably mixed according to the actual printing requirements. The specific steps are as follows:

[0056] (1.1) Preparing an inorganic mixture: mixing measured ordinary Portland cement and sand evenly according to a certain proportion to prepare an inorganic mixture;

[0057] (1.2) Preparing an admixture mixture: uniformly mix the measured retarder and water reducer according to the proportion to prepare an admixture mixture;

[0058] (1.3) Keep stirring and mixing at a low speed, and evenly add the admixture mixture into the inorganic mixture to ensure that the admixture can be evenly dispersed in the inorganic mixture;

[0059] (1.4) Preparation of component A: Add measured water into a mixing device and mix thoroughly for about 5 minutes. At this point, component A in the setting control material based on the two-component 3D printing mortar is prepared.

[0060] (2) Preparation of component B:

[0061] The coagulant, viscosity modifier and powdered carrier were dissolved in mixing water and mixed at a speed of 30 r / min for 5 min. At this point, component B in the coagulation regulating material based on the two-component 3D printing mortar was prepared.

[0062] (3) Preparation of coagulation control materials based on two-component 3D printing mortar

[0063] The prepared A and B components are pumped into the two-component 3D printer at a volume ratio of A:B=8:1. After being mixed by a spiral stirring extruder, the coagulation regulating material based on the two-component 3D printing mortar is extruded. At this point, the preparation of the coagulation regulating material based on the two-component 3D printing mortar is completed.

[0064] Example 2

[0065] A two-component 3D printing mortar setting regulating material comprises component A and component B; the mass percentages of the raw materials of component A are as follows: 42.9% of ordinary Portland cement, 2.9% of sand, 13% of mixing water, retarder: 0.8% of sodium gluconate, water reducer: 0.4% of polycarboxylic acid high-performance powdered water reducer; the particle size range of the sand is 0.18 mm to 4.75 mm, and the fineness modulus is 1.8 to 3.5; the mass percentages of the raw materials of component B are as follows: accelerator: 22% of aluminum sulfate 18hydrate, viscosity modifier: 0.3% of anionic polyacrylamide, powdered carrier: 48% of quartz powder, and 29.7% of mixing water.

[0066] Preparation of setting regulating materials based on two-component 3D printing mortar:

[0067] The preparation process of components A and B is the same as that of Example 1; the prepared components A and B are pumped into the two-component 3D printer according to the volume ratio of A:B=9:1, and the coagulation regulating material based on the two-component 3D printing mortar is extruded after mixing by the spiral stirring extruder. At this point, the preparation of the coagulation regulating material based on the two-component 3D printing mortar is completed.

[0068] Example 3

[0069] A two-component 3D printing mortar setting regulating material comprises component A and component B; the mass percentages of the raw materials of component A are as follows: 42.9% of ordinary Portland cement, 42.9% of sand, 13% of mixing water, retarder: 0.8% of sodium gluconate, water reducer: 0.4% of polycarboxylic acid high-performance powdered water reducer; the particle size range of the sand is 0.18 mm to 4.75 mm, and the fineness modulus is 1.8 to 3.5; the mass percentages of the raw materials of component B are as follows: accelerator: 23% of aluminum sulfate 18hydrate, viscosity modifier: 0.3% of anionic polyacrylamide, powdered carrier: 47% of quartz powder, and 29.7% of mixing water.

[0070] Preparation of setting regulating materials based on two-component 3D printing mortar:

[0071] The preparation processes of components A and B are the same as those in Example 1; the prepared components A and B are pumped into a two-component 3D printer at a volume ratio of A:B = 10:1 respectively, and after being mixed by a spiral stirring extrusion head, a setting control material based on two-component 3D printing mortar is extruded. Thus, the preparation of the setting control material based on two-component 3D printing mortar is completed.

[0072] Example 4

[0073] A setting control material for two-component 3D printing mortar, comprising component A and component B; the mass percentages of the raw materials of component A are as follows: ordinary Portland cement 42.9%, sand 42.9%, mixing water 13%, setting retarder: sodium gluconate 0.8%, water reducer: polycarboxylic acid high-performance powdered water reducer 0.4%; the particle size range of the sand is 0.18 mm to 4.75 mm, and the fineness modulus is 1.8 to 3.5; the mass percentages of the raw materials of component B are as follows: setting accelerator: aluminum sulfate octadecahydrate 24%, viscosity modifier: anionic polyacrylamide 0.3%, powdered carrier: quartz powder 46%, mixing water 29.7%.

[0074] Prepare a setting control material based on two-component 3D printing mortar:

[0075] The preparation processes of components A and B are the same as those in Example 1; the prepared components A and B are pumped into a two-component 3D printer at a volume ratio of A:B = 11:1 respectively, and after being mixed by a spiral stirring extrusion head, a setting control material based on two-component 3D printing mortar is extruded. Thus, the setting control material based on two-component 3D printing mortar.

[0076] Example 5

[0077] A setting control material for two-component 3D printing mortar, comprising component A and component B; the mass percentages of the raw materials of component A are as follows: ordinary Portland cement 42.9%, sand 42.9%, mixing water 13%, setting retarder: sodium gluconate 0.8%, water reducer: polycarboxylic acid high-performance powdered water reducer 0.4%; the particle size range of the sand is 0.18 mm to 4.75 mm, and the fineness modulus is 1.8 to 3.5; the mass percentages of the raw materials of component B are as follows: setting accelerator: aluminum sulfate octadecahydrate 25%, viscosity modifier: anionic polyacrylamide 0.3%, powdered carrier: quartz powder 45%, mixing water 29.7%.

[0078] Prepare a setting control material based on two-component 3D printing mortar:

[0079] The preparation processes of Component A and Component B are the same as those in Example 1; the prepared Components A and B are pumped into a two-component 3D printer at a volume ratio of A:B = 12:1 respectively, and after being mixed by a spiral stirring extrusion head, a setting control material based on two-component 3D printing mortar is extruded. Thus, the preparation of the setting control material based on two-component 3D printing mortar is completed.

[0080] Example 6

[0081] A setting control material for two-component 3D printing mortar, comprising Component A and Component B; the mass percentages of the raw materials of Component A are as follows: ordinary Portland cement 42.84%, sand 42.84%, mixing water 13%, retarder: sodium gluconate 0.88%, water reducer: polycarboxylic acid high-performance powdered water reducer 0.44%; the particle size range of the sand is 0.18 mm to 4.75 mm, and the fineness modulus is 1.8 to 3.5; the mass percentages of the raw materials of Component B are as follows: setting accelerator: aluminum sulfate octadecahydrate 25%, viscosity modifier: anionic polyacrylamide 0.3%, powdered carrier: quartz powder 45%, mixing water 29.7%.

[0082] Prepare a setting control material based on two-component 3D printing mortar:

[0083] The preparation processes of Component A and Component B are the same as those in Example 1; the prepared Components A and B are pumped into a two-component 3D printer at a volume ratio of A:B = 12:1 respectively, and after being mixed by a spiral stirring extrusion head, a setting control material based on two-component 3D printing mortar is extruded. Thus, the preparation of the setting control material based on two-component 3D printing mortar is completed.

[0084] Example 7

[0085] A setting control material for two-component 3D printing mortar, comprising Component A and Component B; the mass percentages of the raw materials of Component A are as follows: ordinary Portland cement 43.3%, sand 43.3%, mixing water 13%, retarder: sodium gluconate 0.8%, water reducer: polycarboxylic acid high-performance powdered water reducer 0.4%; the particle size range of the sand is 0.18 mm to 4.75 mm, and the fineness modulus is 1.8 to 3.5; the mass percentages of the raw materials of Component B are as follows: setting accelerator: aluminum sulfate octadecahydrate 25%, viscosity modifier: anionic polyacrylamide 0.4%, powdered carrier: quartz powder 45%, mixing water 29.6%.

[0086] Prepare a setting control material based on two-component 3D printing mortar:

[0087] The preparation processes of Components A and B are the same as those in Example 1; the prepared Components A and B are respectively pumped into a two-component 3D printer according to a volume ratio of A:B = 12:1, and after being mixed by a spiral stirring and extrusion head, a setting control material based on two-component 3D printing mortar is extruded. Thus, the preparation of the setting control material based on two-component 3D printing mortar is completed.

[0088] Table 1 Performance of the setting control materials based on two-component 3D printing mortar obtained in Examples 1-5

[0089]

[0090] Comparative Example 1

[0091] Anionic polyacrylamide, calcium nitrate, aluminum sulfate, Beform, AEA type expansive agent, and triethanolamine are respectively mixed with ordinary Portland cement, and the mixing ratios are successively 2‰ - 5‰ for anionic polyacrylamide, 3% - 7% for calcium nitrate, 1% - 5% for aluminum sulfate octadecahydrate, 10% for Beform, 3% - 7% for AEA, and 0.1% - 1% for triethanolamine. Their static yield stresses are immediately tested after mixing, and the numerical magnitudes of the early yield stress growth are observed. It can be found that anionic polyacrylamide, calcium nitrate, and aluminum sulfate have better effects, while the other three have poorer effects, so they are not considered for use.

[0092] Comparative Example 2

[0093] Component A is prepared according to the method in Example 1, wherein the mass percentage of the water reducing agent is adjusted to 0.8‰, 1.0‰, and 1.2‰ of ordinary Portland cement. Its fluidity and setting time are tested.

[0094] Comparative Example 3

[0095] Component A is prepared according to the method in Example 1, wherein the mass percentage of the retarder is adjusted to 1‰, 2‰, and 3‰ of ordinary Portland cement. Its fluidity and setting time are tested.

[0096] Comparative Example 4

[0097] Anionic polyacrylamide and calcium nitrate are mixed with ordinary Portland cement, wherein the dosage of anionic polyacrylamide is fixed at 0.047‰ of the cementitious material, and the dosage of calcium nitrate varies between 0% and 7%. Its fluidity and constructability are tested.

[0098] Comparative Example 5

[0099] Anionic polyacrylamide and aluminum sulfate are mixed with ordinary Portland cement, wherein the dosage of anionic polyacrylamide is fixed at 0.047‰ of the cementitious material, and the dosage of aluminum sulfate varies between 0% and 3%. Its fluidity and constructability are tested.

[0100] AsFigure 1 As shown, it is a comparison of the effects of different materials used in the preliminary experiment on the development of early yield stress. Among them, Beform is a sulfoaluminate clinker; AEA is an aluminate-type concrete expansion agent; C6H 15 NO3 is triethanolamine; APAM is anionic polyacrylamide; Figure 1 The last two figures in

[0101] Figure 2 are the time-dependent change diagrams of the fluidity of component A under different superplasticizer dosages in Comparative Example 2. The superplasticizer dosages are 0.8‰, 1.0‰, and 1.2‰ respectively, and the change in its fluidity is observed within 0 - 180 min; Figure 3 are the setting time change diagrams of component A under different superplasticizer dosages in Comparative Example 4, and the setting time conditions with superplasticizer dosages of 0.8‰, 1.0‰, and 1.2‰ respectively.

[0102] Figure 4 are the time-dependent change diagrams of the fluidity of component A under different retarding agent dosages in Comparative Example 3, where the dosage of the superplasticizer remains unchanged at 1‰, and the retarding agent dosages are 1‰, 2‰, and 3‰; Figure 5 are the setting time change diagrams of component A under different retarding agent dosages in Comparative Example 5, and the retarding agent dosages are 1‰, 2‰, and 3‰.

[0103] Figure 6 are the change diagrams of the fluidity and slump of the components obtained by compounding anionic polyacrylamide, calcium nitrate, and aluminum sulfate with cement respectively in Comparative Example 1 with the change in dosage. It can be found that when used alone, anionic polyacrylamide has a greater impact on fluidity and slump (due to its physical effect), while the other two materials have a smaller impact. To achieve better results, compound admixture should be considered;

[0104] Figure 7 are the change diagrams of the fluidity and slump of the components obtained in Comparative Examples 4 and 5 with the change in dosage. It can be seen that the effect is better when the viscosity modifier and the accelerating agent are used in combination;

[0105] Figure 8 are the time-dependent changes of the slump and fluidity of the components obtained by compounding anionic polyacrylamide, calcium nitrate, and aluminum sulfate with cement respectively in Comparative Example 1. It can be seen that when used alone, the initial changes in slump and fluidity of calcium nitrate and aluminum sulfate are not large enough, and anionic polyacrylamide can meet the requirements, but its strength development has been proven insufficient. Therefore, compound admixture should be considered.

[0106] Figure 9 are the change diagrams of the fluidity and slump of the components obtained in Comparative Examples 4 and 5 with the change in dosage. It can be seen that when used in combination, the advantages of the changes in early slump and fluidity are obvious;

[0107] Figure 10 For the change in the yield strength of the single-component group and the compound-component group in the penetration resistance experiment in the first 1 h, it can be found that the components incorporated with aluminum sulfate or calcium nitrate can meet the requirements in terms of the development rate; Figure 11 For the change in the yield strength of the single-component group and the compound-component group in the penetration resistance experiment in the first 10 min, it can be found that in the initial stage of mixing, the yield strength of the single-component group is relatively lower than that of the compound-component group.

[0108] Figure 12 For the change in the yield strength of the aluminum sulfate group under different dosages and the condition of whether the mixing is uniform, it can be found that aluminum sulfate can have a high strength development even when the mixing is not uniform.

[0109] Figure 13 For the compressive property diagrams of the components obtained from Comparative Examples 4 and 5 at 3 days, 7 days, 28 days, and 56 days, it can be found that the group of anionic polyacrylamide + aluminum sulfate actually used has a high strength development rate and less shrinkage of the later strength.

[0110] Figure 14 For the compressive property diagrams of the components obtained from Comparative Example 5 in the two cases of printing and casting at 3 days, 7 days, 28 days, and 56 days, it can be found that the difference in the compressive strength between the cast and printed components is relatively small, and the compressive strength in the X direction of the printed parts is the highest.

[0111] Figure 15 For the flexural property diagrams of the components obtained from Comparative Examples 4 and 5 at 3 days, 7 days, 28 days, and 56 days, it can be found that the group of anionic polyacrylamide + aluminum sulfate actually used has a high strength development rate and less shrinkage of the later strength.

[0112] Figure 16 For the compressive property diagrams of the components obtained from Comparative Example 5 in the two cases of printing and casting at 3 days, 7 days, 28 days, and 56 days, it can be found that in terms of the flexural strength, the printed parts have a certain advantage over the cast parts, and the flexural strength in the Z direction is the highest.

[0113] In summary, the setting control material for the two-component 3D printing mortar of the present invention has a relatively short setting time, the initial setting time is greater than 10 min and less than 20 min, the final setting time is about 30 min, and it has the characteristics of early strength and high strength. The 3-day compressive strength generally reaches more than 30 Mpa, the workability before mixing is good, the pumping is simple, the initial setting time of Component A is about 4 h, and the stability is good, which can meet the requirements of a long window period. It hardens rapidly after mixing and can meet the requirements of the continuity and rapidity of the 3D printing process. The 7-day compressive strength is generally greater than 50 Mpa, the 28-day strength is generally greater than 60 Mpa, and there is no obvious shrinkage phenomenon in the 56-day strength, which can meet the requirements for the strength of 3D printed buildings. The material selection and preparation technology involved are of great significance for promoting the development and popularization of 3D printing building technology.

Claims

1. A setting control material for a two-component 3D printing mortar, characterized in that, It includes component A and component B; The mass percentages of the raw materials in component A are as follows: The mass percentages of the raw materials in component B are as follows:

2. The setting control material for the two-component 3D printing mortar according to claim 1, characterized in that The coagulant is aluminum sulfate octadecahydrate.

3. The setting control material for the two-component 3D printing mortar according to claim 1, characterized in that The viscosity modifier is anionic polyacrylamide; its molecular weight is 18 million to 30 million.

4. The setting control material for the two-component 3D printing mortar according to claim 1, wherein The powdery carrier is quartz powder, and the particle size of the quartz powder is 300 to 400 mesh.

5. The setting control material for the two-component 3D printing mortar according to claim 1, characterized in that, The retarder is sodium gluconate.

6. The setting control material for the two-component 3D printing mortar according to claim 1, characterized in that, The water reducer is a polycarboxylate high-performance powdery water reducer, and its water reduction rate is greater than 40%.

7. The setting control material for the two-component 3D printing mortar according to claim 1, characterized in that, The particle size range of the sand is 0.18 mm to 4.75 mm, and the fineness modulus is 1.8 to 3.

5.

8. A preparation method of a setting control material for a two-component 3D printing mortar according to claim 1, characterized in that, It includes the following steps: (1) Weigh the cementitious material, sand, mixing water, retarder, and water reducer in proportion, mix them, and then add mixing water. After mixing, component A is obtained; (2) Weigh the coagulant, viscosity modifier, powdery carrier, and mixing water in proportion, and obtain component B after mixing; (3) Pump component A and component B into a two-component 3D printing head respectively, mix them and then extrude to obtain the setting control material of the two-component 3D printing mortar.

9. The preparation method of the setting control material for the two-component 3D printing mortar according to claim 8, characterized in that, In step (2), first mix the coagulant, viscosity modifier and powdery carrier, and then add mixing water when in use.

10. The preparation method of the setting control material for the two-component 3D printing mortar according to claim 8, wherein, In step (3), the pumping flow rate of component A is 6 to 8 L / min; the pumping flow rate of component B is 0.6 to 0.8 L / min.

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