CN110723951B - Modified raw soil material for 3D printing and preparation method thereof - Google Patents

Abstract

The invention discloses a modified raw soil material for 3D printing and a preparation method thereof, wherein the raw soil material for 3D printing comprises polyvinyl butyral, calcium lignosulfonate, a water reducing agent, a waterproof agent, an early strength agent, raw soil, fibers, alum, gypsum, lime, rapid hardening portland cement, aluminate cement, glutinous rice pulp and water. The raw soil material for 3D printing has the advantages of short setting time, good cohesiveness, no slump and capability of meeting the requirements of 3D printing technology; meanwhile, the high-strength waterproof paint has the advantages of high early strength, high late strength, high cold resistance, high impact resistance, high waterproof performance and the like, and the preparation method is simple and is easy to operate and implement.

Description

A kind of modified raw soil material for 3D printing and preparation method thereof

technical field

The invention relates to the field of construction engineering materials, in particular to a modified raw soil material for 3D printing and a preparation method thereof.

Background technique

As a rapid prototyping technology, 3D printing is based on digital model files, using various printing materials such as metal, plastic, cement, etc., to build objects by layer-by-layer printing. Revolution" core technology. Compared with traditional manufacturing techniques, 3D printing does not need to manufacture molds in advance, does not require complex manufacturing processes, and can obtain the final product with a very small amount of labor participation. Therefore, it has a series of advantages such as saving labor and raw materials, simple manufacturing process and good product integration.

3D printing materials are an important material condition for the development of 3D printing technology, and the development of 3D printing materials determines the application prospects of 3D printing. As a natural building material, raw soil material has the advantages of green environmental protection, low cost, simple preparation process, recyclability, and convenience for local materials. It is especially suitable for areas with relatively shortage of resources and relatively backward economy. The strength of raw soil materials mainly comes from the cohesion of clay and the occlusion between irregular particles, so the strength is not high, especially the flexural and shear strengths are generally low. As a new technology without template support, 3D printing raw soil material has great development prospects. In order to meet the requirements of 3D printing, the raw soil material should have high early strength, short setting time, and suitable aggregate particle size. Therefore, it is urgent to develop a 3D printing raw soil material with fast setting speed, high early strength, good bonding performance and strong plasticity.

SUMMARY OF THE INVENTION

In view of the problems existing in the prior art, the purpose of the present invention is to provide a modified raw soil material for 3D printing and a preparation method thereof. The raw soil material for 3D printing has the advantages of short setting time, good cohesion, and no The slump can meet the requirements of 3D printing technology; at the same time, it has the advantages of high early strength, late strength, cold resistance and impact resistance, and good waterproof performance, and the preparation method is simple and easy to operate.

In order to achieve the above objects, the present invention adopts the following technical solutions to achieve.

(1) A modified raw soil material for 3D printing, including the following raw materials: polyvinyl butyral, calcium lignosulfonate, water reducing agent, waterproofing agent, early strength agent, raw soil, fiber, alum, gypsum , lime, fast-hardening Portland cement, aluminate cement, sticky rice slurry and water.

Preferably, the water reducer is a polycarboxylate water reducer, a naphthalene-based superplasticizer or a sulfamate superplasticizer.

Further preferably, the polycarboxylate water reducer is an ester type polycarboxylate water reducer or an ether type polycarboxylate water reducer.

Preferably, the waterproofing agent is silicone.

Preferably, the early strength agent is one or more of calcium oxide, triethanolamine or potassium bicarbonate.

Preferably, the fibers are polyethylene fibers, polypropylene fibers, flax fibers, sugarcane fibers or straw.

Preferably, the dosage of the raw materials is: polyvinyl butyral 0.05-0.125%, calcium lignosulfonate 0.03-0.102%, water reducing agent 0.15-0.20%, waterproofing agent 0.08-0.115%, early strength agent 0.041 -0.06%, raw soil 82-90%, fiber 0.4-0.8%, alum 0.09-0.13%, gypsum 0.41-0.92%, lime 1.13-1.52%, fast-hardening Portland cement 1.035-1.27%, aluminate cement 0.35-0.83%, glutinous rice pulp 0.37-0.44%, and the balance is water.

(2) A method for preparing a modified raw soil material for 3D printing, comprising the following steps:

Step 1, under sealing conditions, polyvinyl butyral, calcium lignosulfonate and water are mixed and stirred to obtain a modified material, which is for subsequent use;

Step 2, mixing the water reducing agent, water repellent, early strength agent and water to obtain a mixture of auxiliary agents, for subsequent use;

Step 3, uniformly mix raw soil, fiber, alum, gypsum, lime, fast-hardening Portland cement, and aluminate cement to obtain a mixture for subsequent use;

Step 4: First, mix the modified material and the auxiliary mixture, stir for one time, then add the mixture, glutinous rice slurry and water, and stir for the second time to obtain a modified raw soil material for 3D printing.

Preferably, in step 1, the stirring temperature is 30-50° C., and the stirring time is 3-4 h.

Preferably, in step 1, the water content of the modified material is 70-90%.

Preferably, the dosage ratio of water in step 1, step 2, and step 4 is: (1-3): (2-4): (5-9).

Preferably, in step 4, the time for one stirring is 20-30 min.

Preferably, in step 4, the secondary stirring is carried out by a cement mortar mixer, and the mixing is first low-speed stirring for 2 minutes, then high-speed stirring for 5 minutes, and finally low-speed stirring for 2 minutes; wherein, the low speed is the cement mortar mixer rotating 140±5r/min , revolution 62±5r/min; high speed is 285±10r/min rotation and 125±10r/min revolution.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The modified material for 3D printing obtained by the present invention has a short setting time, good cohesion, and no slump; at the same time, it has high early strength, late strength, cold resistance and impact resistance, and good water resistance, etc. The advantages are that it can improve soil solidification time and compressive strength to meet the needs of 3D printing. The preparation method is simple, easy to operate and implement, low in material cost and transportation cost, saves resources, protects the environment, and has remarkable economic and social benefits.

(2) In the modified material for 3D printing obtained by the present invention, the polyvinyl butyral molecule has good cold resistance and impact resistance, and at the same time has good binding force, and is easy to stick to various surfaces; wood Calcium sulfonate has a hydrophobic group and a hydrophilic group. The hydrophobic group is directionally adsorbed on the surface of the particles, and the hydrophilic group points to the aqueous solution to form a single-molecule or multi-molecular adsorption film, so that the particles repel each other due to the same charge on the surface. It is dispersed, and excess water is released from the particles to achieve the purpose of reducing the solidification time, thereby shortening the solidification time of the raw soil material. The adhesion and durability of glutinous rice pulp to raw soil materials were improved. The addition of gypsum and aluminate cement effectively improved the early strength and crack resistance of the raw soil material.

Detailed ways

The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

Example 1

A preparation method of a modified raw soil material for 3D printing, comprising the following steps:

Step 1: Mix 0.059% polyvinyl butyral, 0.042% calcium lignosulfonate and water at a temperature of 42° C. and under sealing conditions, and stir for 3.5 hours to obtain a modified material for use. Among them, the moisture content of the modified material is 72%.

Step 2, mixing 0.153% ester polycarboxylate water reducing agent, 0.08% organosilicon, 0.047% calcium oxide and water to obtain an auxiliary agent mixture, which is ready for use.

Step 3, mix 88.182% raw soil, 0.476% rice straw (rice straw), 0.106% alum, 0.532% gypsum, 1.144% lime, 1.039% fast-hardening Portland cement, and 0.464% aluminate cement to obtain a mixture ,spare.

Step 4: First mix the modified material and the auxiliary mixture, stir for 25 minutes at a time, then add the mixture, 0.402% glutinous rice slurry and water, and stir for the second time (the second mixing is carried out with a cement mortar mixer, and the stirring is to first stir at a low speed for 2 minutes. , then high-speed stirring for 5 minutes, and finally low-speed stirring for 2 minutes; among them, the low speed is the rotation of the cement mortar mixer 140±5r/min, the revolution is 62±5r/min; the high speed is the rotation of the cement mortar mixer 285±10r/min, the revolution is 125±10r /min) to obtain a modified raw soil material for 3D printing; wherein, the dosage ratio of water in step 1, step 2 and step 4 is 2:3:7.

Example 2

A preparation method of a modified raw soil material for 3D printing, comprising the following steps:

Step 1: Mix 0.059% polyvinyl butyral, 0.042% calcium lignosulfonate and water at a temperature of 45° C. and under sealing conditions, and stir for 3 hours to obtain a modified material for use. Among them, the moisture content of the modified material is 70%.

In step 2, 0.153% of naphthalene-based superplasticizer, 0.08% of organic silicon, 0.047% of early strength agent and water are mixed to obtain a mixture of auxiliary agents for use. Wherein, the early strength agent contains calcium oxide and potassium bicarbonate in a mass ratio of 1:2.

Step 3, mix 87.359% raw soil, 0.476% straw, 0.106% alum, 0.913% gypsum, 1.144% lime, 1.039% fast-hardening Portland cement, and 0.824% aluminate cement to obtain a mixture for use.

Step 4: First mix the modified material and the auxiliary mixture, stir for 25 minutes at a time, then add the mixture, 0.402% glutinous rice slurry and water, and stir for the second time (the second mixing is carried out with a cement mortar mixer, and the stirring is to first stir at a low speed for 2 minutes. , then high-speed stirring for 5 minutes, and finally low-speed stirring for 2 minutes; among them, the low speed is the rotation of the cement mortar mixer 140±5r/min, the revolution is 62±5r/min; the high speed is the rotation of the cement mortar mixer 285±10r/min, the revolution is 125±10r /min) to obtain a modified raw soil material for 3D printing; wherein, the dosage ratio of water in step 1, step 2 and step 4 is 2:3:7.

Example 3

A preparation method of a modified raw soil material for 3D printing, comprising the following steps:

Step 1: Mix 0.076% polyvinyl butyral, 0.065% calcium lignosulfonate and water at a temperature of 40° C. and under sealing conditions, and stir for 4 hours to obtain a modified material for use. Among them, the moisture content of the modified material is 75%.

Step 2, mixing 0.186% ether polycarboxylate water reducing agent, 0.104% organosilicon, 0.054% triethanolamine and water to obtain an auxiliary agent mixture, which is ready for use.

Step 3, mix 88.81% raw soil, 0.476% straw, 0.091% alum, 0.429% gypsum, 1.152% lime, 1.22% fast-hardening Portland cement, and 0.625% aluminate cement to obtain a mixture for use.

Step 4, firstly mix the modified material and the adjuvant mixture, stir for 25 minutes at a time, then add the mixture, 0.43% glutinous rice slurry and water, and stir for the second time (the second stirring is carried out by a cement mortar mixer, and the stirring is to first stir at a low speed for 2 minutes. , then high-speed stirring for 5 minutes, and finally low-speed stirring for 2 minutes; among them, the low speed is the rotation of the cement mortar mixer 140±5r/min, the revolution is 62±5r/min; the high speed is the rotation of the cement mortar mixer 285±10r/min, the revolution is 125±10r /min) to obtain a modified raw soil material for 3D printing; wherein, the dosage ratio of water in step 1, step 2 and step 4 is 2:3:7.

Example 4

A preparation method of a modified raw soil material for 3D printing, comprising the following steps:

Step 1: Mix 0.087% polyvinyl butyral, 0.066% calcium lignosulfonate and water at a temperature of 40° C. and under sealing conditions, and stir for 3.5 hours to obtain a modified material for use. Among them, the moisture content of the modified material is 78%.

Step 2, mixing 0.175% ether polycarboxylate water reducing agent, 0.115% organosilicon, 0.041% potassium bicarbonate and water to obtain an auxiliary agent mixture, which is ready for use.

Step 3, mix 86% raw soil, 0.6% polyethylene fiber, 0.11% alum, 0.5% gypsum, 1.325% lime, 1.15% fast-hardening Portland cement, and 0.585% aluminate cement to obtain a mixture for use .

Step 4, first mix the modified material and the auxiliary mixture, stir for 25 minutes at a time, then add the mixture, 0.37% glutinous rice slurry and water, and stir for the second time (the second stirring is carried out with a cement mortar mixer, and the stirring is to first stir at a low speed for 2 minutes. , then high-speed stirring for 5 minutes, and finally low-speed stirring for 2 minutes; among them, the low speed is the rotation of the cement mortar mixer 140±5r/min, the revolution is 62±5r/min; the high speed is the rotation of the cement mortar mixer 285±10r/min, the revolution is 125±10r /min) to obtain a modified raw soil material for 3D printing; wherein, the dosage ratio of water in step 1, step 2 and step 4 is: 2:3:8.

Example 5

A preparation method of a modified raw soil material for 3D printing, comprising the following steps:

Step 1: Mix 0.125% polyvinyl butyral, 0.102% calcium lignosulfonate and water at a temperature of 30° C. and under sealing conditions, and stir for 4 hours to obtain a modified material for use. Among them, the moisture content of the modified material is 77%.

In step 2, 0.20% sulfamate superplasticizer, 0.115% organosilicon, 0.05% triethanolamine and water are mixed to obtain a mixture of auxiliary agents for use.

Step 3, mix 82% raw soil, 0.476% polypropylene fiber, 0.09% alum, 0.59% gypsum, 1.52% lime, 1.27% fast-hardening Portland cement, and 0.82% aluminate cement to obtain a mixture for use .

Step 4, firstly mix the modified material and the auxiliary mixture, stir for 25 minutes at a time, then add the mixture, 0.44% glutinous rice slurry and water, and stir for the second time (the second stirring uses a cement mortar mixer, and the stirring is to first stir at a low speed for 2 minutes. , then high-speed stirring for 5 minutes, and finally low-speed stirring for 2 minutes; among them, the low speed is the rotation of the cement mortar mixer 140±5r/min, the revolution is 62±5r/min; the high speed is the rotation of the cement mortar mixer 285±10r/min, the revolution is 125±10r /min) to obtain a modified raw soil material for 3D printing; wherein, the dosage ratio of water in step 1, step 2 and step 4 is: 3:2:5.

Example 6

A preparation method of a modified raw soil material for 3D printing, comprising the following steps:

Step 1: Mix 0.05% polyvinyl butyral, 0.066% calcium lignosulfonate and water at a temperature of 50° C. and under sealing conditions, and stir for 3 hours to obtain a modified material for use. Among them, the moisture content of the modified material is 76%.

Step 2, mixing 0.15% naphthalene-based superplasticizer, 0.097% organic silicon, 0.06% calcium oxide and water to obtain an adjuvant mixture for use.

Step 3, mix 90% raw soil, 0.476% sugarcane fiber, 0.13% alum, 0.41% gypsum, 1.13% lime, 1.035% fast-hardening Portland cement, and 0.35% aluminate cement to obtain a mixture for use.

Step 4: First mix the modified material and the auxiliary agent mixture, stir for 25 minutes at a time, then add the mixture, 0.405% glutinous rice slurry and water, and stir for the second time (the second mixing is carried out with a cement mortar mixer, and the stirring is to first stir at a low speed for 2 minutes. , then high-speed stirring for 5 minutes, and finally low-speed stirring for 2 minutes; among them, the low speed is the rotation of the cement mortar mixer 140±5r/min, the revolution is 62±5r/min; the high speed is the rotation of the cement mortar mixer 285±10r/min, the revolution is 125±10r /min) to obtain a modified raw soil material for 3D printing; wherein, the dosage ratio of water in step 1, step 2 and step 4 is: 1:4:9.

Comparative Example 1

A preparation method of a modified raw soil material for 3D printing without polyvinyl butyral and calcium lignosulfonate, the specific preparation method is the same as that in Example 2, the difference is that step 1 is not included, and no preparation modification is required. sexual material.

Comparative Example 2

A preparation method of a modified raw soil material for 3D printing without polyvinyl butyral, the specific preparation method is the same as that of embodiment 2, the difference is that polyvinyl butyral is not added in step 1.

Comparative Example 3

A preparation method of a modified raw soil material for 3D printing without calcium lignosulfonate, the specific preparation method is the same as that of Example 2, the difference is that calcium lignosulfonate is not added in step 1.

Comparative Example 4

A preparation method of a modified raw soil material for 3D printing without gypsum and aluminate cement. The specific preparation method is the same as that of Example 2, except that gypsum and aluminate cement are not added in step 3.

test

The setting time, fluidity, compressive strength and flexural strength of the modified raw soil materials for 3D printing obtained in Examples 1-3 and the modified raw soil materials for 3D printing obtained in Comparative Examples 1-4 were tested respectively. as follows:

1) Test method:

Preparation of test piece: The size of the test piece is 40*40*160mm, and the specific production method refers to GB/T17671─1999 "Inspection Method of Cement Mortar Strength (ISO Method)", the temperature of the test piece is 20±2℃, and the relative humidity is 95% Conditioned to test age.

Setting time: refer to GB/T50080-2002 "Standards for Test Methods of Performance of Ordinary Concrete Mixtures".

Fluidity: measure with reference to the experimental method specified in Appendix A.0.2 of GB/T5044-2008 "Technical Specifications for Application of Cement-based Grouting Materials".

Flexural strength and compressive strength: refer to the provisions in GB/T17671─1999 "Inspection Method for Cement Mortar Strength (ISO Method)".

2) Test results: The measurement results of setting time, fluidity, flexural strength and compressive strength are shown in Table 1.

Table 1 Performance test results

It can be seen from Table 1 that the data of Examples 1-3 shows that Example 2 is the best example, the modified raw soil material has the shortest setting time, and the difference between the compressive and flexural strength of Example 3 is small.

From the data of Example 2 and Comparative Examples 1-3, it can be seen that the simultaneous addition of polyvinyl butyral and calcium lignosulfonate in the raw soil material has played a synergistic effect, making the setting time short and the compressive strength improved. This may be: the polyvinyl butyral molecule has good cold resistance and impact resistance, and at the same time has good bonding force, easy to stick to various surfaces, and can form stable and sticky with calcium lignosulfonate. The structure of the joint force can improve the compressive strength of the roadbed; calcium lignosulfonate has hydrophobic groups and hydrophilic groups, the hydrophobic groups are oriented and adsorbed on the surface of the particles, and the hydrophilic groups point to the aqueous solution, forming a single molecule Or multi-molecular adsorption film, so that the particles are dispersed due to the mutual repulsion of the same charge on the surface, and excess water is released from the particles to achieve the purpose of reducing the solidification time, thereby shortening the solidification time of the raw soil material.

From the initial setting time and final setting time of Examples 1-3 and Comparative Example 4, it is shown that the gypsum powder and aluminate cement added to the modified raw soil material for 3D printing of the present invention can significantly improve the setting characteristics of the raw soil material. , which greatly shortens the setting time of modified raw soil materials for 3D printing, and can meet the requirements of 3D printing for rapid solidification.

Although the present invention has been described in detail with general description and specific embodiments in this specification, some modifications or improvements can be made on the basis of the present invention, which will be obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention fall within the scope of the claimed protection of the present invention.

Claims (9)

1. The modified raw soil material for 3D printing is characterized by comprising the following raw materials: polyvinyl butyral, calcium lignosulfonate, a water reducing agent, a waterproof agent, an early strength agent, raw soil, fiber, alum, gypsum, lime, quick-hardening portland cement, aluminate cement, glutinous rice pulp and water;

wherein the dosage of the raw materials is as follows: 0.05 to 0.125 percent of polyvinyl butyral, 0.03 to 0.102 percent of calcium lignosulfonate, 0.15 to 0.20 percent of water reducing agent, 0.08 to 0.115 percent of waterproof agent, 0.041 to 0.06 percent of early strength agent, 82 to 90 percent of raw soil, 0.4 to 0.8 percent of fiber, 0.09 to 0.13 percent of alum, 0.41 to 0.92 percent of gypsum, 1.13 to 1.52 percent of lime, 1.035 to 1.27 percent of rapid hardening silicate cement, 0.35 to 0.83 percent of aluminate cement, 0.37 to 0.44 percent of glutinous rice pulp and the balance of water.

2. The modified raw soil material for 3D printing according to claim 1, wherein the water reducing agent is a polycarboxylic acid water reducing agent, a naphthalene-based high-efficiency water reducing agent or a sulfamate high-efficiency water reducing agent.

3. The modified raw soil material for 3D printing according to claim 2, wherein the polycarboxylate water reducer is an ester polycarboxylate water reducer or an ether polycarboxylate water reducer.

4. The modified immature soil material for 3D printing as claimed in claim 1, wherein said water repellent agent is silicone.

5. The modified immature soil material for 3D printing as claimed in claim 1, wherein the early strength agent is calcium oxide, triethanolamine or potassium bicarbonate.

6. The modified immature soil material for 3D printing as claimed in claim 1, wherein said fibers are polyethylene fibers, polypropylene fibers, flax fibers, sugar cane fibers or straw.

7. The method for preparing the modified raw soil material for 3D printing according to claim 1, comprising the steps of:

step 1, mixing polyvinyl butyral, calcium lignosulfonate and water under a sealed condition, and stirring to obtain a modified material for later use;

step 2, mixing a water reducing agent, a waterproof agent, an early strength agent and water to obtain an auxiliary agent mixture for later use;

step 3, mixing the raw soil, the fibers, the alum, the gypsum, the lime, the quick-hardening portland cement and the aluminate cement uniformly to obtain a mixture for later use;

and 4, mixing the modified material and the auxiliary agent mixture, stirring for the first time, adding the mixture, the glutinous rice pulp and the water, and stirring for the second time to obtain the modified raw soil material for 3D printing.

8. The method for preparing the modified raw soil material for 3D printing according to claim 7, wherein in the step 1, the stirring temperature is 30-50 ℃, and the stirring time is 3-4 h; the water content of the modified material is 70-90%.

9. The method for preparing a modified raw soil material for 3D printing according to claim 7, wherein in the step 4, the time for one stirring is 20-30 min.