A calcium-silicate-based clay-based recycled aggregate concrete for 3D printing and its manufacturing method

Abstract

The present invention discloses a calcium-silicate-based clay-based recycled aggregate concrete for 3D printing and a manufacturing method thereof. The calcium-silicate-based clay-based recycled aggregate concrete for 3D printing comprises the following raw materials in parts by weight: 45-95 parts of 3D printing mortar and 5-55 parts of calcium-silicate-based clay-based recycled aggregate for 3D printing. The 3D printing mortar comprises the following materials in parts by mass: 37.9-48.8 parts of sand, 26.8-40.8 parts of curing agent, 2.2-4.2 parts of additive, 0.41-0.60 parts of chopped fiber, and 15.8-23.8 parts of water. The particle size of the sand is less than 1.18 mm. The curing agent comprises an alkali-activated cementitious material. Since the raw materials of the calcium-silicate-based clay-based recycled aggregate for 3D printing used in the present invention are cheap and easily available, the cost of building 3D printing materials is reduced, and the technical problem of efficient and high-value resource utilization of engineering waste soil solid waste is effectively solved.

Description

Technical Field

[0001] The present invention relates to the field of building 3D printing materials, and particularly to a calcium-silicate-based clay-based recycled aggregate concrete for 3D printing and a manufacturing method thereof. Background Art

[0002] In October 2019, the team of Ma Guowei from Hebei University of Technology adopted the prefabricated concrete 3D printing technology to build a simulated Zhaozhou Bridge (located on the Beichen Campus of Hebei University of Technology, built according to a 1:2 reduced scale of the Zhaozhou Bridge, with a span of 18.04 m and a total length of 28.1 m); in November 2019, the School of Architecture of Tsinghua University and Shanghai Smart Bay Science and Technology Park cooperated to 3D print a concrete bridge (14.1 m long and 4 m wide); in November 2019, the China National Building Technology Center and the South China Company of China State Construction Engineering Corporation Second Bureau jointly printed the world's first in-situ 3D printed double-layer demonstration building (located in the Longchuan Industrial Park, Longchuan County, Heyuan City, Guangdong Province, 7.2 meters high, with an area of 230 m 2 , and the printing completion time was about 60 hours). In addition, 3D printed concrete can also print wind turbine towers, municipal landscapes and small items, and foamed concrete, etc.

[0003] At present, due to the relatively high labor cost in the construction field, and during the construction process, dust, noise, vibration and heavy physical labor seriously affect the physical and mental health of construction workers, and the use of mechanized and intelligent 3D printing construction technology has gradually become the only way for the high-quality development of the construction industry. Due to different 3D printing inkjet materials in building 3D printing, the requirements for 3D printing equipment and processes are also different. At present, the widely used 3D printing equipment mainly uses cement mortar as the inkjet material. When these equipment switch to using cement concrete added with coarse aggregate of stones as the inkjet material, normal printing will be affected due to many mismatching factors such as equipment motors and operating systems. Therefore, the low-cost large-scale production of coarse aggregate suitable for 3D printing cement mortar equipment is a way to reduce the current construction cost of building 3D printing and further promote the large-scale and wide application of building 3D printing construction technology. Summary of the Invention

[0004] The purpose of the present invention is to propose a calcium-silicate-based clay-based recycled aggregate concrete for 3D printing and a manufacturing method thereof in view of the current lack of low-cost and large-scale producible coarse aggregate suitable for 3D printing mortar.

[0005] The present invention provides a calcium-silicate-based clay-based recycled aggregate concrete for 3D printing, and the calcium-silicate-based clay-based recycled aggregate concrete for 3D printing comprises the following raw materials in parts by weight: 45-95 parts of 3D printing mortar, and 5-55 parts of calcium-silicate-based clay-based recycled aggregate for 3D printing;

[0006] The 3D printing mortar comprises the following materials in parts by mass: 37.9 - 48.8 parts of sand, 26.8 - 40.8 parts of curing agent, 2.2 - 4.2 parts of additive, 0.41 - 0.60 parts of chopped fiber, and 15.8 - 23.8 parts of water;

[0007] The particle size of the sand is less than 1.18 mm;

[0008] The curing agent is an alkali-activated cementitious material;

[0009] The additive is one of rapid hardening sulphoaluminate cement and rapid hardening ferroaluminate cement;

[0010] The chopped fiber is one of polyvinyl alcohol fiber, polyvinyl alcohol nitrile fiber, polypropylene fiber, and polyacrylonitrile fiber, and the length of the chopped fiber is 3 mm;

[0011] The calcium-silicate-based clayey recycled aggregate for 3D printing comprises the following raw materials in parts by weight: 60 parts of construction waste soil, 6.7 - 20 parts of cementitious material, 0 - 13.3 parts of admixture, and 16 - 20 parts of water;

[0012] The construction waste soil is powder obtained by crushing the mud cake after separating the construction waste soil, sand, and mud through natural drying, with a particle size less than 2.36 mm and a moisture content of 7%;

[0013] The cementitious material is one of ordinary Portland cement, white Portland cement, and alkali-activated cementitious material;

[0014] The admixture is one of the waste residue in the ceramic firing process and stone powder. The particle size of the waste residue in the ceramic firing process is less than 1.18 mm, and the stone powder is powder particles with a particle size of 0.074 mm generated during the crushing of waste concrete;

[0015] The water is groundwater, surface water, or seawater.

[0016] Further, the activator used for the alkali-activated cementitious material is one or two of water glass and sulfate activator;

[0017] The sulfate activator comprises the following raw materials in parts by weight: 27 - 80 parts of quicklime powder, 0 - 67 parts of gypsum dihydrate, and 6 - 20 parts of sodium sulfate.

[0018] Another object of the present invention is to provide a manufacturing method for the calcium-silicate-based clayey recycled aggregate for 3D printing. The manufacturing method comprises the following steps:

[0019] S1. Set the required weight parts of the raw materials of the calcium-silicate-based clayey recycled aggregate for 3D printing through the control system of the production equipment for the calcium-silicate-based clayey recycled aggregate for 3D printing;

[0020] S2. Weigh the raw materials of calcium-silicate-based clay recycled aggregates for 3D printing according to the designed ratio. The clay-based materials are weighed in two parts, with the mass percentages of the first part and the second part being 70% and 30% respectively. Add the weighed cementitious materials to the first part of the clay materials and stir, then add the second part of the clay-based materials and the weighed admixtures and water, and stir again.

[0021] S3. Add the stirred mixture to the extrusion molding equipment for calcium-silicate-based clay recycled aggregates for 3D printing, and extrude the calcium-silicate-based clay recycled aggregates for 3D printing.

[0022] S4. Carry out indoor curing, immersion curing or carbonation curing on the calcium-silicate-based clay recycled aggregates for 3D printing.

[0023] S5. According to the mix proportion design of the calcium-silicate-based clay recycled aggregates for 3D printing, weigh the calculated 3D printing mortar and the calcium-silicate-based clay recycled aggregates for 3D printing. First, stir the 3D printing mortar, then add the calcium-silicate-based clay recycled aggregates for 3D printing, and pump the stirred mixture into the hopper of the 3D printing equipment for 3D printing.

[0024] Furthermore, the particle size of the calcium-silicate-based clay recycled aggregates for 3D printing is 10 mm - 30 mm.

[0025] Furthermore, the 28-day cylinder compressive strength of the calcium-silicate-based clay recycled aggregates for 3D printing is greater than 2 MPa, the crushing index is less than 30%, and the 1-hour water absorption rate is less than 20%.

[0026] The present invention adopts the extrusion molding technology to efficiently recycle engineering waste soil. Since the used clay-based materials are cheap and easily available, it not only realizes the large-scale production of coarse aggregates for 3D printing at low cost, but also effectively improves the resource utilization rate and added value of the recycled aggregates, and reduces the cost of construction materials for 3D printing projects. The produced calcium-silicate-based clay recycled aggregates for 3D printing can also be recycled after being discarded, further reducing the engineering application cost of the coarse aggregates for 3D printing. At the same time, it effectively solves the problems of high cost, ecological environment damage and unsustainable engineering, social and ecological governance of engineering waste soil treatment. Brief Description of the Drawings

[0027] Figure 1 It is a schematic diagram of calcium-silicate-based clay recycled aggregates for 3D printing. Detailed Embodiments

[0028] To enable those skilled in the art to better understand the solution of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence.

[0030] Control Example 1

[0031] The clay-based recycled aggregate concrete for 3D printing in this control example includes the following raw materials by weight: 45 parts of 3D printing mortar and 55 parts of clay-based recycled aggregate for 3D printing. The 3D printing mortar includes the following materials by mass: 40.8 parts of sand, 40.8 parts of curing agent, 2.2 parts of additive, 0.41 parts of chopped fiber, and 15.8 parts of water. The particle size of the sand is less than 1.18 mm. The curing agent is 42.5-grade ordinary Portland cement. The additive is rapid-hardening sulphoaluminate cement. The chopped fiber is 3-mm polyvinyl alcohol fiber. The particle size of the clay-based recycled aggregate is 10 mm.

[0032] The clay-based recycled aggregate for 3D printing includes the following raw materials by weight: 60 parts of construction waste soil with a moisture content of 7%, 20 parts of 42.5-grade ordinary Portland cement, and 20 parts of tap water. The construction waste soil is powder obtained by crushing the mud cake after the separation of construction waste soil and sand through natural drying, and the particle size is less than 2.36 mm. Weigh the raw materials of the clay-based recycled aggregate for 3D printing according to the designed ratio. The clay-based material is weighed in two portions, and the mass percentages of the first portion and the second portion are 70% and 30% respectively. Add the weighed cementitious materials to the first portion of the clay material and stir, then add the second portion of the clay-based material and add the weighed admixtures and water and stir; add the stirred mixture to the extrusion molding equipment for the clay-based recycled aggregate for 3D printing to extrude the clay-based recycled aggregate for 3D printing; carry out indoor curing on the clay-based recycled aggregate for 3D printing. The aggregate produced by the extrusion molding equipment is as Figure 1 shown. The cylinder compressive strength of the clay-based recycled aggregate for 3D printing after 28 days of indoor curing is 2.9 MPa, the crushing index is 16.5%, and the 1-hour water absorption rate is 11%; the cylinder compressive strength of the clay-based recycled aggregate for 3D printing after 28 days of immersion curing is 4.1 MPa, the crushing index is 14.3%, and the 1-hour water absorption rate is 9%.

[0033] Control Example 2

[0034] This comparative example's clay-based recycled aggregate concrete for 3D printing comprises the following raw materials in parts by weight: 65 parts of 3D printing mortar and 35 parts of clay-based recycled aggregate for 3D printing. The 3D printing mortar comprises the following materials in parts by mass: 37.9 parts of sand, 37.9 parts of curing agent, 3.5 parts of additive, 0.51 part of chopped fiber, and 20.2 parts of water. The sand has a particle size less than 1.18 mm. The curing agent is ordinary Portland cement. The additive is rapid hardening ferroaluminate cement. The chopped fiber is 3 mm polyvinyl alcohol nitrile fiber. The particle size of the clay-based recycled aggregate is 10 mm.

[0035] The clay-based recycled aggregate for 3D printing comprises the following raw materials in parts by weight: 60 parts of construction waste soil with a moisture content of 7%, 13.3 parts of 42.5-grade ordinary Portland cement, 6.7 parts of waste residue during ceramic firing, and 20 parts of tap water. The construction waste soil is powder obtained by natural drying and crushing of the mud cake after separation of engineering muck and sand, with a particle size less than 2.36 mm. The particle size of the waste residue during ceramic firing is 1.18 mm. Weigh the raw materials of the clay-based recycled aggregate for 3D printing according to the designed ratio. The clay-based material is weighed in two portions, and the mass percentages of the first portion and the second portion are 70% and 30% respectively. Add the weighed cementitious material to the first portion of the clay material and stir, then add the second portion of the clay-based material and add the weighed admixture and water and stir. Add the stirred mixture to the extrusion molding equipment for the clay-based recycled aggregate for 3D printing to extrude the clay-based recycled aggregate for 3D printing. Carry out indoor curing on the clay-based recycled aggregate for 3D printing. The aggregate produced by the extrusion molding equipment is as Figure 1 shown. After 28 days of indoor curing, the cylinder compressive strength of the clay-based recycled aggregate for 3D printing is 2.4 MPa, the crushing index is 17.6%, and the 1-hour water absorption rate is 10%. After 28 days of immersion curing, the cylinder compressive strength of the clay-based recycled aggregate for 3D printing is 3.9 MPa, the crushing index is 14.8%, and the 1-hour water absorption rate is 9%.

[0036] Comparative Example 3

[0037] This comparative example's clay-based recycled aggregate concrete for 3D printing, the clay-based recycled aggregate for 3D printing comprises the following raw materials in parts by weight: 75 parts of 3D printing mortar and 25 parts of clay-based recycled aggregate for 3D printing. The 3D printing mortar comprises the following materials in parts by mass: 48.8 parts of sand, 29.3 parts of curing agent, 2.6 parts of additive, 0.49 part of chopped fiber, and 18.9 parts of water. The sand has a particle size less than 1.18 mm. The curing agent is 42.5-grade white Portland cement. The additive is rapid hardening sulphoaluminate cement. The chopped fiber is 3 mm polypropylene fiber. The particle size of the clay-based recycled aggregate is 10 mm.

[0038] The clay-based recycled aggregate for 3D printing includes the following raw materials in parts by weight: 60 parts of engineering waste soil with a moisture content of 7%, 17.3 parts of 42.5-grade ordinary Portland cement, 6.7 parts of waste residues in the ceramic firing process, and 16 parts of tap water. The engineering waste soil is a powder obtained by crushing the mud cake after the separation of mud and sand from the engineering slag soil and naturally drying it, and the particle size is less than 2.36 mm. The particle size of the waste residues in the ceramic firing process is 1.18 mm. The raw materials of clay-based recycled aggregate for 3D printing are weighed according to the designed ratio. The clay-based material is weighed in two portions, and the mass percentages of the first portion and the second portion are 70% and 30% respectively. The weighed cementitious material is added to the first portion of the clay material and stirred. Then the second portion of the clay-based material is added and the weighed admixture and water are added and stirred. The stirred mixture is added to the clay-based recycled aggregate extrusion molding equipment for 3D printing to extrude the clay-based recycled aggregate for 3D printing. The clay-based recycled aggregate for 3D printing is cured indoors. The aggregate produced by the extrusion molding equipment is as follows: Figure 1 As shown, the cylinder compressive strength of the clay-based recycled aggregate for 3D printing after indoor curing for 28 days is 3.0 MPa, the crushing index is 29%, and the water absorption rate is 9% in 1 hour; the cylinder compressive strength of the clay-based recycled aggregate for 3D printing after immersion curing for 28 days is 4.2 MPa, the crushing index is 26%, and the water absorption rate is 8% in 1 hour.

[0039] Example 1

[0040] The calcium-silicon clay-based recycled aggregate concrete for 3D printing in this embodiment includes the following raw materials in parts by weight: 85 parts of 3D printing mortar, 15 parts of calcium-silicon clay-based recycled aggregate for 3D printing, the 3D printing mortar includes the following materials in parts by weight: 44.6 parts of sand, 26.8 parts of curing agent, 4.2 parts of additives, 0.60 parts of chopped fibers, and 23.8 parts of water, the sand particle size is less than 1.18 mm, the curing agent is an alkali-activated cementitious material, the activator is water glass, the additive is fast-hardening ferroaluminate cement, the chopped fibers are 3 mm polypropylene fibers, and the clay-based recycled aggregate particle size is 20 mm.

[0041] The calcium-silicate clay-based recycled aggregate for 3D printing comprises the following raw materials in parts by weight: 60 parts of construction waste soil with a water content of 7%, 6.7 parts of 42.5-grade ordinary Portland cement, 13.3 parts of waste residue during ceramic firing, and 20 parts of tap water. The construction waste soil is powder obtained by naturally drying and then crushing the mud cake after separating the mud and sand from construction waste soil, with a particle size less than 2.36 mm. The particle size of the waste residue during ceramic firing is 1.18 mm. Weigh the raw materials of the calcium-silicate clay-based recycled aggregate for 3D printing according to the designed ratio. The clay-based material is weighed in two portions, and the mass percentages of the first portion and the second portion are 70% and 30% respectively. Add the weighed cementitious material to the first portion of the clay material and stir, then add the second portion of the clay-based material and add the weighed admixture and water and stir; Add the stirred mixture to the extrusion molding equipment for the calcium-silicate clay-based recycled aggregate for 3D printing to extrude the calcium-silicate clay-based recycled aggregate for 3D printing; Carry out indoor curing on the calcium-silicate clay-based recycled aggregate for 3D printing. The aggregate produced by the extrusion molding equipment is as Figure 1 shown. The cylinder compressive strength of the calcium-silicate clay-based recycled aggregate for 3D printing after 28 days of indoor curing is 2.4 MPa, the crushing index is 17.5%, and the 1-hour water absorption rate is 12%; The cylinder compressive strength of the calcium-silicate clay-based recycled aggregate for 3D printing after 28 days of immersion curing is 3.5 MPa, the crushing index is 15.3%, and the 1-hour water absorption rate is 10%.

[0042] Example 2

[0043] The calcium-silicate clay-based recycled aggregate concrete for 3D printing in this example comprises the following raw materials in parts by weight: 90 parts of 3D printing mortar and 10 parts of the calcium-silicate clay-based recycled aggregate for 3D printing. The 3D printing mortar comprises the following materials in parts by mass: 40.8 parts of sand, 40.8 parts of curing agent, 2.2 parts of additive, 0.41 part of chopped fiber, and 15.8 parts of water. The particle size of the sand is less than 1.18 mm. The curing agent is an alkali-activated cementitious material, and the activator is a sulfate activator. The sulfate activator comprises the following raw materials in parts by weight: 27 parts of quicklime powder, 67 parts of gypsum dihydrate, and 6 parts of sodium sulfate. The additive is a rapid hardening sulphoaluminate cement. The chopped fiber is 3-mm polypropylene fiber. The particle size of the clay-based recycled aggregate is 20 mm.

[0044] The calcium-silicate clay-based recycled aggregate for 3D printing comprises the following raw materials in parts by weight: 60 parts of construction waste soil with a water content of 7%, 13.3 parts of 42.5-grade ordinary Portland cement, 6.7 parts of stone powder, and 20 parts of tap water. The construction waste soil is powder obtained by naturally drying and then crushing the mud cake after separating the mud and sand from the construction waste soil, with a particle size less than 2.36 mm. The stone powder is powder particles with a particle size of 0.074 mm generated during the crushing of concrete. Weigh the raw materials of the calcium-silicate clay-based recycled aggregate for 3D printing according to the designed ratio. The clay-based material is weighed in two parts, and the mass percentages of the first part and the second part are 70% and 30% respectively. Add the weighed cementitious material to the first part of the clay material and stir, then add the second part of the clay-based material and add the weighed admixture and water and stir; Add the stirred mixture to the extrusion molding equipment for the calcium-silicate clay-based recycled aggregate for 3D printing to extrude the calcium-silicate clay-based recycled aggregate for 3D printing; Carry out indoor curing on the calcium-silicate clay-based recycled aggregate for 3D printing. The aggregate produced by the extrusion molding equipment is as Figure 1 shown. The cylinder compressive strength of the calcium-silicate clay-based recycled aggregate for 3D printing after 28 days of indoor curing is 3.0 MPa, the crushing index is 28.7%, and the 1-hour water absorption rate is 11%; The cylinder compressive strength of the calcium-silicate clay-based recycled aggregate for 3D printing after 28 days of immersion curing is 4.9 MPa, the crushing index is 26.4%, and the 1-hour water absorption rate is 9%.

[0045] Example 3

[0046] The calcium-silicate clay-based recycled aggregate concrete for 3D printing in this example comprises the following raw materials in parts by weight: 95 parts of 3D printing mortar and 5 parts of the calcium-silicate clay-based recycled aggregate for 3D printing. The 3D printing mortar comprises the following materials in parts by mass: 40.8 parts of sand, 40.8 parts of curing agent, 2.2 parts of additive, 0.41 part of chopped fiber, and 15.8 parts of water. The particle size of the sand is less than 1.18 mm. The curing agent is an alkali-activated cementitious material, and the activator is a sulfate activator. The sulfate activator comprises the following raw materials in parts by weight: 53.5 parts of quicklime powder, 33.5 parts of gypsum dihydrate, and 13 parts of sodium sulfate. The additive is rapid hardening sulphoaluminate cement. The chopped fiber is 3-mm polyacrylonitrile fiber. The particle size of the clay-based recycled aggregate is 30 mm.

[0047] The calcium-silicate clay-based recycled aggregate for 3D printing comprises the following raw materials in parts by weight: 60 parts of construction waste soil with a moisture content of 7%, 6.7 parts of 42.5-grade ordinary Portland cement, 13.3 parts of stone powder, and 20 parts of tap water. The construction waste soil is a powder obtained by naturally drying and then crushing the mud cake after separating the construction waste soil, sand, and mud, with a particle size less than 2.36 mm. The stone powder is a powder particle with a particle size of 0.074 mm generated during the crushing of concrete. Weigh the raw materials of the calcium-silicate clay-based recycled aggregate for 3D printing according to the designed ratio. Weigh the clay-based material in two portions, and the mass percentages of the first portion and the second portion are 70% and 30% respectively. Add the weighed cementitious material to the first portion of the clay material and stir, then add the second portion of the clay-based material and add the weighed admixture and water and stir; add the stirred mixture to the extrusion molding equipment for the calcium-silicate clay-based recycled aggregate for 3D printing to extrude the calcium-silicate clay-based recycled aggregate for 3D printing; conduct indoor curing on the calcium-silicate clay-based recycled aggregate for 3D printing. The aggregate produced by the extrusion molding equipment is as Figure 1 shown. The cylinder compressive strength of the calcium-silicate clay-based recycled aggregate for 3D printing after 28 days of indoor curing is 2.5 MPa, the crushing index is 25.9%, and the 1-hour water absorption rate is 13%; the cylinder compressive strength of the calcium-silicate clay-based recycled aggregate for 3D printing after 28 days of immersion curing is 3.6 MPa, the crushing index is 23.5%, and the 1-hour water absorption rate is 11%.

[0048] By using an arc, the calcium-silicate clay-based recycled aggregate for 3D printing is designed into a structure with an arch shape as shown in Figure 1 shown, especially a near-spindle shape with arches on both sides, effectively exerting the advantage of the arch structure having a high compressive strength.

[0049] The calcium-silicate clay-based recycled aggregate for 3D printing is integrally formed by adding a cementitious material, an admixture, and water and using extrusion technology, having the advantages of fast molding, low manufacturing cost, and no waste of raw materials during the molding process, effectively reducing the cost of 3D printing inkjet materials. At the same time, the construction waste soil is fully made into recycled aggregate that can meet the engineering needs, realizing the efficient resource utilization of construction waste soil. In addition, in the embodiment of the present invention, by using an alkali-activated cementitious material as a curing agent, the strength of the aggregate can be effectively improved under the condition of the same water absorption rate of the aggregate.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that after reading the specification of this application, they can still modify or equivalently replace the specific implementation manners of the present invention, but these modifications or changes do not depart from the protection scope of the pending claims of the present invention application.

Claims

1. A calcium-silicon clay-based recycled aggregate concrete for 3D printing, characterized in that: The calcium-silicon clay-based recycled aggregate concrete for 3D printing comprises the following raw materials in parts by weight: 45-95 parts of 3D printing mortar, 5-55 parts of calcium-silicon clay-based recycled aggregate for 3D printing; The 3D printing mortar includes the following materials by weight: 37.9-48.8 parts of sand, 26.8-40.8 parts of curing agent, 2.2-4.2 parts of additives, 0.41-0.60 parts of chopped fibers, and 15.8-23.8 parts of water; the particle size of the sand is less than 1.18 mm; The additive is one of fast-hardening sulphoaluminate cement and fast-hardening ferroaluminate cement; The chopped fibers are one of polyvinyl alcohol fibers, polypropylene fibers, and polyacrylonitrile fibers, and the length of the chopped fibers is 3 mm; The curing agent includes an alkali-activated gelling material; The activator used in the alkali-activated gelling material is a sulfate activator; The sulfate activator comprises the following raw materials in parts by weight: 27 to 53.5 parts of quicklime powder, 33.5 to 67 parts of dihydrate gypsum, and 6 to 13 parts of sodium sulfate; The calcium-silicon clay-based recycled aggregate for 3D printing includes the following raw materials in parts by weight: 60 parts of engineering waste soil, 6.7-20 parts of cementitious materials, 0-13.3 parts of admixtures, and 16-20 parts of water; The engineering waste soil is a powder obtained by crushing the mud cake after the separation of engineering slag and sand into powder after natural drying, with a particle size of less than 2.36 mm and a moisture content of 7%; The cementitious material is one of ordinary silicate cement, white silicate cement and alkali-activated cementitious material; The admixture is one of waste residue and stone powder in the ceramic firing process, the particle size of the waste residue in the ceramic firing process is less than 1.18 mm, and the stone powder is powder particles with a particle size of 0.074 mm generated in the process of crushing waste concrete; The calcium-silicon clay-based recycled aggregate for 3D printing is a shuttle-shaped structure with arches on both sides; The preparation method of calcium-silicon clay-based recycled aggregate for 3D printing: S1. Setting the required weight of calcium-silicon clay-based recycled aggregate raw materials for 3D printing through the control system of the calcium-silicon clay-based recycled aggregate production equipment for 3D printing; S2. Weigh the raw materials of calcium-silicon clay-based recycled aggregate for 3D printing according to the designed ratio. Weigh the clay base material in two portions, with the mass percentages of the first portion and the second portion being 70% and 30% respectively. Add the weighed cementitious material to the first portion of the clay material and stir, then add the second portion of the clay base material and add the weighed admixture and water and stir; S3, adding the stirred mixture to the calcium-silicon clay-based recycled aggregate extrusion molding equipment for 3D printing, and extruding the calcium-silicon clay-based recycled aggregate for 3D printing; S4. Carry out indoor curing, water immersion curing or carbonization curing on calcium-silicon clay-based recycled aggregates for 3D printing.

2. The calcium-silicon clay-based recycled aggregate concrete for 3D printing according to claim 1, characterized in that: The water is groundwater, surface water or seawater.

3. The calcium-silicon clay-based recycled aggregate concrete for 3D printing according to claim 1, characterized in that: The method for manufacturing calcium-silicon clay-based recycled aggregate concrete for 3D printing comprises the following steps: According to the mix ratio design of calcium-silicon clay-based recycled aggregate concrete for 3D printing, weigh and calculate the 3D printing mortar and calcium-silicon clay-based recycled aggregate for 3D printing, stir the 3D printing mortar first, then add the calcium-silicon clay-based recycled aggregate for 3D printing, stir and pump it into the hopper of the 3D printing equipment for 3D printing.

4. The calcium-silicon clay-based recycled aggregate concrete for 3D printing according to claim 1, characterized in that: The particle size of the calcium-silicon clay-based recycled aggregate for 3D printing is 10mm-30mm.

5. The calcium-silicon clay-based recycled aggregate concrete for 3D printing according to claim 1, characterized in that: The calcium-silicon clay-based recycled aggregate for 3D printing has a 28d cylinder compressive strength greater than 2MPa, a crushing index less than 30%, and a 1h water absorption rate less than 20%.

Images