Preparation method of active biological mortar and 3D printing method

Abstract

The application relates to a preparation method of active biological mortar, and comprises the following steps: S1, urea, a calcium source, corncob powder, L-cysteine, trehalose and nano-hydroxyapatite are added into bacterial liquid of bacillus pasteurii, and stirring culture is carried out; after complete crystallization and precipitation, supernatant is poured out, and the remaining part is centrifuged to obtain active biological slurry with a water content of 42-28%; S2, active magnesium oxide is premixed with 0.5-1% potassium dihydrogen phosphate, and is aged at 50-65 DEG C for 20-30h to obtain an enhancer; after standard sand and wind-sand soil are pre-dried, the two are mixed according to a mass ratio of 1:1-3 to obtain mixed sand; 2-5% of the enhancer and 10-15% of waste ceramic powder are added into the mixed sand to obtain aggregate; S3, the active biological slurry and the aggregate are mixed, and 0.2-0.5% of cellulose nanocrystals are added to obtain active biological mortar, which can replace cement mortar in 3D printing cement mortar technology, and is beneficial to energy saving and emission reduction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of active biological mortar materials, and particularly relates to a preparation method of an active biological mortar and a 3D printing method. BACKGROUND

[0002] In recent years, intelligent construction technology has developed rapidly, and the deep integration of intelligentization and informatization with the traditional construction industry has given rise to the innovation of 3D printing building materials. Although traditional 3D printing cement mortar has advantages in terms of automated construction and complex structure molding (such as reducing the dependence on formwork and reducing labor costs), it still has the following key bottlenecks: (1) single material function: conventional mortar relies on cement-based binder materials, which have high carbon emissions (about 0.6-0.9 tons of CO2 per ton of cement) and lack biological activity, and cannot respond to environmental changes or self-repair damage. (2) Contradiction between printing performance and durability: in order to meet the rheological requirements of 3D printing (such as shear thinning behavior and extrudability), thickeners or fibers are often added, but this will sacrifice the later strength (28-day compressive strength is generally ≤40 MPa) or cause interlayer adhesion defects. (3) Insufficient sustainability: traditional materials are difficult to degrade, and construction waste accounts for more than 30% of global solid waste.

[0003] The research on bio-based alternative materials is still in the laboratory stage. The breakthrough of microbial mineralization technology (such as Bacillus pasteurii induced CaCO3 precipitation) provides a new way to solve the self-repair problem, but the survival rate of microorganisms in alkaline mortar environment (pH>10) is less than 20%. In terms of 3D printing adaptability, existing biological mortar focuses on static performance and lacks systematic optimization of dynamic printing process (such as matching of extrusion rate and setting time), which leads to easy collapse or cracking of the printed body. SUMMARY

[0004] (I) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present application provides a preparation method of an active biological mortar and a 3D printing method, which improves the survival rate of microorganisms in alkaline mortar through bio-material collaborative design, controls the rheological properties of mortar, and improves the matching of extrusion rate and setting time to optimize the 3D printing performance, thereby replacing the cement mortar in the 3D printing cement mortar technology, which is conducive to energy saving and emission reduction, and better embodies the concept of green building.

[0006] (II) Technical solutions

[0007] In a first aspect, the present application provides a preparation method of an active biological mortar, which comprises:

[0008] S1, preparing an active biological paste

[0009] 1x10 7-5x10 8 The bacterial solution of the 5x10 CFU / mL Bacillus pasteurii is added with 0.4M-0.6M urea, a calcium source with a urea concentration of 1-1.2 times, 2-6% corn cob powder, 0.01-0.05% L-cysteine, 0.1-0.3% trehalose, and 0.05-0.1% nano-hydroxyapatite, and then stirred and cultured at a temperature of 30-40℃ for 6-10h;

[0010] After standing for 8-12h, the supernatant is discarded after complete precipitation of the crystals, and the remaining part is centrifuged to obtain an active biological slurry with a water content of 42-28%;

[0011] S2, preparation of aggregate

[0012] The active magnesium oxide is premixed with 0.5-1% potassium dihydrogen phosphate, and then aged at 50-65℃ for 20-30h to obtain a reinforcing agent; the aeolian soil and standard sand are pre-dried, mixed in a mass ratio of 1:1-3, and then 2-5% of the reinforcing agent and 10-15% of the waste ceramic powder are added to the mixed sand to obtain the aggregate;

[0013] S3, preparation of active biological mortar

[0014] The active biological slurry prepared in S1 and the aggregate prepared in S2 are mixed and uniformly stirred, 0.2-0.5% cellulose nanocrystals are added, and shear thinning treatment is performed to obtain an active biological mortar with a flow degree of not less than 180mm and a consistency of less than 35mm.

[0015] According to the preferred embodiment of the present application, in S1, the preparation method of the bacterial solution of Bacillus pasteurii is as follows: the bacterial strain of Bacillus pasteurii is domesticated and cultured in a bacterial solution culture medium for 3-4 times, each time with an inoculation amount of 1%~5% into the bacterial solution culture medium, a culture temperature of 30℃-40℃, a rotation speed of 180~200r / min, a pH of 6.0~6.5, and a culture time of 2~4d; the last domesticated and cultured solution is used to prepare the active biological slurry; in the bacterial solution culture medium, the concentration of yeast powder is 18-25g / L, (NH4)2SO4 accounts for 8-15g / L, and the concentration of tris-hydroxymethyl aminomethane buffer is 0.1-0.15M.

[0016] According to the preferred embodiment of the present application, in S1, the calcium source is calcium chloride or wood calcium or a combination of calcium chloride and wood calcium; low-frequency pulse ultrasonic waves are used during the stirring and culture stage.

[0017] According to the preferred embodiment of the present application, in S2, the particle size of the waste ceramic powder is less than 0.15mm.

[0018] According to the preferred embodiment of the present application, in S3, the active biological slurry and the aggregate are mixed in a mass ratio of 1:(3~8).

[0019] In a second aspect, the present application relates to an active biological mortar prepared by any of the above embodiments.

[0020] In a third aspect, the present application provides a 3D printing method based on the active biological mortar, which comprises: using the active biological mortar as the base material, loading into the storage tank of the 3D printing device, keeping the mixture of the material uniform under stirring, 3D printing according to the preset model, after the printing is completed, spraying calcium source nutrient solution on the model for curing, spraying 3-6 times per day, continuously spraying for seven days, and then naturally curing. Preferably, the natural curing time is 5 days.

[0021] Preferably, the calcium source in the calcium source nutrient solution is calcium chloride or wood calcium or a combination of calcium chloride and wood calcium. The wood calcium is reddish brown and has the functions of coloring and adjusting color.

[0022] Preferably, the calcium ion concentration in the calcium source nutrient solution is 0.25M-0.5M.

[0023] Preferably, the calcium source nutrient solution further contains 0.2-0.4M of NH4Cl, 2-4.5% of Nutrient Broth, 0.6-0.8M of CO(NH2)2, 0.1-0.2M of NaHCO3; the pH of the calcium source nutrient solution is 6-7.

[0024] Preferably, during the curing process, the active biological mortar and the calcium source nutrient solution are mixed and sprayed at a mass ratio of 1:1-4.

[0025] (Three) beneficial effects

[0026] In the preparation of the active biological mortar of the present application, 0.1-0.3% trehalose is added to the bacterial solution as a biological protective agent, 0.05-0.1% nano-hydroxyapatite (pH buffer carrier) and 0.01-0.05% L-cysteine (reducing agent), which greatly improves the survival rate of Bacillus pasteurii in harsh environments (high pH), maintains microbial activity, and maintains high activity of urease activity (Bacillus pasteurii at pH≥12 can be more than 70%) at pH≥12. Adding corn cob powder to the bacterial solution can accelerate the reaction rate and improve the Ca 2+conversion rate (shorten the preparation time of active biological slurry, the culture time needs 12-24h without corn cob powder); after the hardening of the slurry, the residual corn cob powder can induce secondary mineralization at the crack. In the stirring culture stage, the CaCO3 crystal particle size in the active biological slurry can be optimized from random distribution to uniform size of 1-3um with low-frequency pulse ultrasonic waves (such as 20kHz, interval 10min / time, 10min each time), which can improve the self-repairing efficiency of the slurry model. The aeolian soil and standard sand in the aggregate are mixed in a mass ratio of 1:1-3, which helps to balance the extrusion flowability retention rate of the slurry and the unconfined compressive strength of the model; the active magnesium oxide can form MgCO3 precipitate in combination with CO3 2- The combination of MgCO3 and the formation of Mg-K-PO4 gel network in the aging process of potassium dihydrogen phosphate can increase the strength of the model, and on the other hand, the phosphate can react with free SiO2 in the aeolian soil to form silicate cement, filling the pores between the sand particles. The aggregate mixed with waste ceramic powder can mainly improve the bulk density of the mixed sand, play a filling effect, and reduce the risk of delamination between the printing layers. Compared with silica sand aggregate, the aggregate in the application can obtain higher interlayer bonding strength, extrusion flowability retention rate, and reduce the drying shrinkage. A small amount of cellulose nanocrystals is added to the slurry, which is a shear thinning modifier to improve the viscosity of the active biological slurry.

[0027] The initial setting time of the active biological slurry of the application is 35-60min, the final setting time is 4-6h, and the viscosity of the slurry is >500Pa·s (anti-collapse) under low shear rate (1s -1 ) and <10Pa·s (easy extrusion) under high shear rate (100s -1 ), which is very suitable for the demand of the dynamic process of 3D printing for the matrix material. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The flow chart of the preparation method of the active biological slurry provided by the application.

[0029] Figure 2 The actual photo of the active biological slurry prepared in Example 1 of the application.

[0030] Figure 3 The flow chart of the 3D printing method based on the active biological slurry.

[0031] Figure 4 The photo of the calcium source nutrient solution used for curing after 3D printing.

[0032] Figure 5 The photo of the model obtained by 3D printing using the active biological slurry of the application. DETAILED DESCRIPTION

[0033] In order to better explain the present application, so as to be understood, the present application is described in detail below by specific embodiments, combined with the drawings. In the present application, unless otherwise specified, all are mass percent. The present application is described by taking the commercially available Bacillus pasteurii strain ATCC 11859 as an example.

[0034] As shown in the flow chart of the preparation method of the active biological mortar provided by the present application, the details are as follows: Figure 1

[0035] Step 1: Preparation of Bacillus pasteurii bacterial liquid

[0036] The strain of Bacillus pasteurii is domesticated and cultured in a bacterial liquid medium for 3-4 times, with an inoculation amount of 1%-5% each time, a culture temperature of 30-40℃, a rotation speed of 180-200r / min, a pH of 6.0-6.5, and a culture duration of 2-4d; the bacterial liquid medium is composed of yeast powder, (NH4)2SO4, tris-hydroxymethyl aminomethane buffer, and deionized water, wherein the concentration of yeast powder in each liter of bacterial liquid medium is 18-25g / L, the concentration of (NH4)2SO4 is 8-15g / L, and the concentration of tris-hydroxymethyl aminomethane buffer is 12-18g / L (buffer concentration 0.1-0.15M). The last domesticated and cultured liquid is used for preparing the active biological slurry.

[0037] Step 2: Preparation of active biological slurry

[0038] The domesticated and cultured liquid prepared in Step 1 is adjusted in concentration to obtain a bacterial liquid containing 1×10 7 -5×10 8 CFU / mL of Bacillus pasteurii. 0.4M-0.6M urea, calcium source with a urea concentration of 1-1.2 times, 2-6% corn cob powder, 0.01-0.05% L-cysteine, 0.1-0.3% trehalose, and 0.05-0.1% nano-hydroxyapatite are added to the bacterial liquid, followed by stirring and culturing, at a temperature of 30-40℃ for 6-10h; after standing for 8-12h until complete crystallization and precipitation (the main component of the crystalline substance is active calcium carbonate), the supernatant is discarded, and the remaining part is centrifuged to obtain an active biological slurry with a water content of 42-28%.

[0039] During the stirring and culturing process, low-frequency pulse ultrasonic treatment can be accompanied, such as 20kHz for 10min, for 10min. This measure is mainly to optimize the CaCO3 crystal particle size in the active biological slurry from random distribution to a uniform size of 1-3μm.

[0040] Step 3: Preparation of aggregate

[0041] ​The active magnesium oxide is premixed with 0.5-1% potassium dihydrogen phosphate, and is aged at 50-65℃ for 20-30h to obtain an enhancer; the aeolian soil and the standard sand are pre-dried, and are mixed in a mass ratio of 1:1-3 to obtain mixed sand, 2-5% of the enhancer and 10-15% of the waste ceramic micro-powder (particle size less than 0.15mm) are added to the mixed sand to obtain the aggregate.

[0042] Step 4: Preparation of active biological mortar

[0043] The active biological mortar and the aggregate are mixed in a mass ratio of 1:3-8, and 0.2-0.5% of cellulose nanocrystals are added and are sheared and thinned to obtain the active biological mortar with a fluidity of not less than 180mm and a consistency of less than 35mm.

[0044] The following is described in combination with specific embodiments of the application.

[0045] Example 1

[0046] The present embodiment provides a preparation method of an active biological mortar, and the whole preparation process is as follows:

[0047] Step 1: Preparation of bacterial solution of Bacillus pasteurii

[0048] The strain of Bacillus pasteurii is domesticated and cultured in a bacterial solution culture medium for 3 times, and is inoculated into the bacterial solution culture medium in a inoculation amount of 5% each time, and is cultured at a temperature of 37℃, a rotation speed of 200r / min and a pH of 6.0-6.5 for 3d. In each liter of the bacterial solution culture medium, the concentration of yeast powder is 20g / L, the concentration of (NH4)2SO4 is 10g / L, and the concentration of tris-hydroxymethyl aminomethane buffer solution is 15.748g / L. The last domesticated and cultured solution is used for preparing the active biological mortar.

[0049] Step 2: Preparation of active biological mortar

[0050] The domesticated and cultured solution prepared in step 1 is adjusted in concentration to obtain a bacterial solution containing 2×10 8 CFU / mL of Bacillus pasteurii. 0.5M urea, 0.55M calcium chloride, 4% corn cob powder, 0.02% L-cysteine, 0.2% trehalose and 0.05% nanometer hydroxyapatite are added to the bacterial solution, and then stirring culture is performed, and the stirring culture is performed at 37℃ for 8h; after the crystallization is analyzed and developed, the solution is left to stand for 10h, and after the crystallization is completely precipitated, the supernatant is poured out, and the remaining part is centrifuged to obtain the active biological mortar with a water content of 44% (as shown in Figure 2 During the stirring culture, low-frequency pulse ultrasonic treatment can be performed, for example, 20kHz, 10min interval, 10min treatment.

[0051] Step 3: Preparation of aggregate

[0052] The active magnesium oxide is premixed with 1% potassium dihydrogen phosphate (1% of the total mass of the mixture), aged at 60°C for 24h, and an enhancer is obtained. During the aging process, the ambient humidity (or trace amount of added water) causes it to gradually dissolve and ionize, releasing PO4 3- with H + , into nanoscale Mg3(PO4)2 gel. The aeolian soil and standard sand are pre-dried, mixed in a mass ratio of 1:3 to obtain mixed sand, 3% of the enhancer and 15% of the waste ceramic micro-powder (particle size less than 0.15mm) are added to the mixed sand to obtain the aggregate.

[0053] Step 4: Preparation of active biological mortar

[0054] The active biological slurry and the aggregate are mixed in a mass ratio of 1:4, uniformly mixed, 0.2% of cellulose nanocrystals are added, and shear-thinning treatment is performed to obtain the active biological mortar. It is measured that the flow degree of the active biological mortar is not less than 180mm and the consistency is less than 35mm.

[0055] Example 2

[0056] The preparation method of the active biological mortar provided in this example is the same as that in Example 1, except that the conditions in Step 2 are changed to:

[0057] A bacterial solution with a bacterial amount of 3×10 8 CFU / mL of Bacillus pasteurii is used. 0.6M urea, 0.66M calcium lignosulfonate, 4% corn cob powder, 0.03% L-cysteine, 0.2% trehalose, and 0.1% nanometer hydroxyapatite are added to the bacterial solution, and then stirring culture is performed. The stirring culture is performed at 37°C for 10h. After the crystallization is complete, the solution is allowed to stand for 10h. After the crystallization is completely precipitated, the supernatant is discarded, and the remaining part is centrifuged to obtain the active biological slurry with a water content of 45%. During the stirring culture, low-frequency pulse ultrasonic treatment can be performed, such as 20kHz for 5min, for 5min.

[0058] The methods and conditions in Steps 1, 3 and 4 in this example are the same as those in Example 1.

[0059] Example 3

[0060] The preparation method of the active biological mortar provided in this example is the same as that in Example 1, except that Step 3 is changed to:

[0061] The active magnesium oxide is premixed with 1% potassium dihydrogen phosphate (1% of the total mass of the mixture), aged at 60°C for 24h, and an enhancer is obtained. The aeolian soil and standard sand are pre-dried, mixed in a mass ratio of 2:3 to obtain mixed sand, 3% of the enhancer and 15% of the waste ceramic micro-powder (particle size less than 0.15mm) are added to the mixed sand to obtain the aggregate.

[0062] The method and conditions of the first to second steps and the fourth step of this example are the same as those of Example 1.

[0063] Example 4

[0064] This example provides a preparation method of active biological mortar, and the preparation process thereof is referred to Example 1, except that the third step is changed to:

[0065] The active magnesium oxide is premixed with 1% potassium dihydrogen phosphate (the potassium dihydrogen phosphate accounts for 1% of the total mass of the mixture), and is aged at 60°C for 24h to obtain a reinforcing agent. The aeolian soil and the standard sand are pre-dried, and are mixed in a mass ratio of 1:1 to obtain mixed sand. The mixed sand is added with 2% of the reinforcing agent and 15% of the waste ceramic micro powder (particle size less than 0.15mm) to obtain the aggregate.

[0066] The method and conditions of the first to second steps and the fourth step of this example are the same as those of Example 1.

[0067] Example 5

[0068] This example provides a preparation method of active biological mortar, and the preparation process thereof is referred to Example 1, except that the fourth step is changed to: the active biological mortar and the aggregate are mixed in a mass ratio of 1:8, and 0.5% of the cellulose nanocrystal is added for shear thinning treatment to obtain the active biological mortar. It is measured that the flow degree of the active biological mortar is not less than 180mm, and the consistency is less than 35mm.

[0069] The method and conditions of the first to second steps and the third step of this example are the same as those of Example 1.

[0070] Example 6

[0071] This example provides a preparation method of active biological mortar, and the preparation process thereof is referred to Example 1, except that the second step is not accompanied by low-frequency pulse ultrasonic treatment.

[0072] The method and conditions of the first step and the third to fourth steps of this example are the same as those of Example 1.

[0073] In order to further illustrate the technical effects brought by some technical features in the present application, the following are some comparative examples.

[0074] Comparative Example 1

[0075] The aggregate of this comparative example does not contain the reinforcing agent prepared from the active magnesium oxide and the potassium dihydrogen phosphate.

[0076] Comparative Example 2

[0077] The aggregate of this comparative example does not contain the waste ceramic micro powder.

[0078] The initial setting time, final setting time, low shear viscosity (1s -1 ) and high shear viscosity (100s -1 ) of the active bio-mortar of Examples 1-6 and Comparative Examples 1-2 were tested, and the active bio-mortar was injected into a mold, vibrated and compacted, and then cured for 12h to obtain a test piece, and the unconfined compressive strength (MPa) of the test piece was tested. The test results are shown in Table 1.

[0079] Table 1:

[0080]

[0081] From the above data, it can be seen that the initial setting time of the active bio-mortar of the present application is 35-60min, the final setting time is 4-6h, the viscosity of the mortar is >500Pa·s (anti-collapse) under low shear rate (1s -1 ), and the viscosity is <10Pa·s (easy to extrude) under high shear rate (100s -1 ), which is very suitable for the requirements of the matrix material in the dynamic process of 3D printing.

[0082] In addition, from Examples 1, 3 and 4, it can be seen that when the aeolian soil and standard sand in the aggregate are mixed at a ratio of 1:3, the compressive strength of the test piece is optimal. From Example 5, it can be seen that when the active bio-mortar and the aggregate are mixed at a mass ratio of 1:8, the initial setting and final setting times of the active bio-mortar are both fast, but the high shear viscosity is still less than 10, still having the performance of easy extrusion, and the test piece has very high compressive strength. From Examples 1 and Comparative Examples 1-2, it can be seen that the addition of the reinforcing agent and the ceramic micro-powder has a significant effect on the compressive strength of the test piece formed by the active bio-mortar; when the reinforcing agent prepared from active magnesium oxide and potassium dihydrogen phosphate is not contained in the aggregate of the mortar under the same conditions, the compressive strength of the test piece decreases significantly; similarly, when the ceramic micro-powder is not contained in the aggregate, the compressive strength of the test piece also decreases significantly.

[0083] Example 7

[0084] The present embodiment provides a 3D printing method of the active bio-mortar obtained in Example 1, and the method flow is shown in Figure 3 , which comprises the following steps:

[0085] (1) designing a model by using software

[0086] The initially designed model is a yurt model, with an inner diameter of about 5cm, an outer diameter of about 20cm, and a model height of about 25cm.

[0087] (2) introducing the active bio-mortar obtained in Example 1 through a feeding port, and then uniformly mixing the material under the stirring of a paddle, and printing the model by using a 3D printer.

[0088] (3) Spraying the active bio-sand mortar and calcium source nutrient solution on the model, 4 times per day, continuously for 7 days, and then natural curing.

[0089] The composition of the calcium source nutrient solution: 0.2M calcium chloride, 0.3M wood calcium, 0.4M NH4Cl, 3% Nutrient Broth, 0.7M CO(NH2)2, 0.15M NaHCO3, with a pH value of 6-7. During the curing process, the active bio-sand mortar and the calcium source nutrient solution are mixed and sprayed at a mass ratio of 1:3; 4 times per day, continuously for 7 days, and then natural curing for 5 days. The calcium source in the calcium source nutrient solution can also be wood calcium (reddish brown), which can be used to prepare the calcium source nutrient solution when the model needs to be colored.

[0090] As shown in Figure 4 , the photos of the calcium source nutrient solution prepared with different calcium sources (calcium chloride, wood calcium, or different combinations of the two), with transparent or varying shades of brown, can be selected for use as needed. As shown in Figure 5 , the picture of the yurt model prepared by 3D printing in this embodiment. After curing, the compressive strength of the model reaches 40.4MPa, which is more than 20 times greater than that of the test piece cured for 12h; the strength growth multiple before and after curing is greater than that of ordinary Portland cement, and during the later maintenance process, repair can be achieved by spraying the active bio-sand mortar and calcium source nutrient solution, which has good environmental protection and energy saving effects, can be integrated into complex structures, and is suitable for the repair of ancient buildings, sculptures, etc.

[0091] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements, or in the case of technical features in the above embodiments do not conflict with each other, can be combined in the manner recorded in the embodiments, and these modifications, replacements or combinations do not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for the preparation of an active bio-mortar for 3D printing, characterized by, It comprises: S1, preparing active biological slurry To the bacterial solution containing 1 x 10 7 -5 x 10 8 The bacterial solution containing 1 x 10 Urea 0.4M-0.6M, calcium source with 1-1.2 times of urea concentration, 2-6% corn cob powder, 0.01-0.05% L-cysteine, 0.1-0.3% trehalose, 0.05-0.1% nano-hydroxyapatite are added, and then stirred and cultured. The stirring and culture is carried out at a temperature of 30-40°C for 6-10h, and low-frequency pulse ultrasonic wave is used during the stirring and culture. After standing for 8-12h, the supernatant is poured out after complete crystallization and precipitation, and the remaining part is centrifuged to obtain active biological slurry with a water content of 42-28%. S2, preparing aggregate The active magnesium oxide is premixed with 0.5-1% potassium dihydrogen phosphate, aged at 50-65℃ for 20-30h to obtain the reinforcing agent; the aeolian soil and the standard sand are pre-dried, mixed in a mass ratio of 1:1-3, and 2-5% of the reinforcing agent and 10-15% of the waste ceramic micro-powder are added to the mixed sand, wherein the particle size of the waste ceramic micro-powder is less than 0.15mm; S3, preparing active biological mortar The active biological slurry prepared in S1 and the aggregate prepared in S2 are mixed in a mass ratio of 1:(3-8), uniformly stirred, and 0.2-0.5% cellulose nanocrystals are added for shear thinning treatment to obtain an active biological mortar with a fluidity of not less than 180mm and a consistency of less than 35mm.

2. The production method according to claim 1, characterized by, In S1, the preparation method of the bacterial solution of Bacillus pasteurii is as follows: the strain of Bacillus pasteurii is domesticated and cultured in a bacterial solution culture medium for 3-4 times, each time with an inoculation amount of 1%-5% into the bacterial solution culture medium, a culture temperature of 30-40℃, a rotation speed of 180-200r / min, a pH of 6.0-6.5, and a culture duration of 2-4d; the last domesticated and cultured solution is used to prepare the active biological slurry; in the bacterial solution culture medium, the concentration of yeast powder is 18-25g / L, (NH4)2SO4 accounts for 8-15g / L, and the concentration of tris-hydroxymethyl aminomethane buffer solution is 0.1-0.15M.

3. The production method according to claim 1, characterized by, In S1, the calcium source is calcium chloride, wood calcium, or a combination of calcium chloride and wood calcium.

4. An active bio-mortar, characterized in that, The preparation method is prepared by any one of claims 1-3.

5. A method of 3D printing based on active biological mortar, characterized in that, It comprises: using the active biological mortar of claim 4 as the base material, loading it into the storage tank of the 3D printing device, keeping the mixture of the material uniform under stirring, 3D printing according to the preset model, after printing, spraying calcium source nutrient solution on the model for curing, spraying 3-6 times a day, continuously spraying for seven days, and then naturally curing.

6. The 3D printing method according to claim 5, characterized in that, The calcium source in the calcium source nutrient solution is calcium chloride, wood calcium, or a combination of calcium chloride and wood calcium; the concentration of calcium ions in the calcium source nutrient solution is 0.25M-0.5M.

7. The 3D printing method according to claim 6, characterized in that, The calcium source nutrient solution also contains 0.2-0.4M NH4Cl, 2-4.5% NutrientBroth, 0.6-0.8M CO(NH2)2, and 0.1-0.2M NaHCO3; the pH of the calcium source nutrient solution is 6-7.

8. The 3D printing method of claim 5, wherein, During the curing process, the active biological mortar and the calcium source nutrient solution are mixed and sprayed in a mass ratio of 1:1-4.

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