Vegetation cement soil material for 3D printing and proportioning method thereof

Abstract

The invention discloses a plant-growing cement soil material for 3D printing and a proportioning method of plant-growing cement soil, and is characterized in that the plant-growing cement soil material comprises raw soil, cement, ferrous sulfate, purified water and plant seeds, the mass ratio of the raw soil to the cement to the ferrous sulfate to the purified water to the plant seeds is 1: 0.3: 0.08: 0.441: 0.091, and the ratio of the raw soil to the cement to the ferrous sulfate to the purified water to the plant seeds is 1: 0.3: 0.087: 0.441: 0.091. According to the pH value of the raw soil material, a proper modified material ratio is adopted for coordination treatment. According to the vegetation cement soil proportioning method for 3D printing, raw materials are deeply screened for multiple times, and the strength and the vegetation performance of the modified vegetation cement soil are inspected through an axial compression test and a pH value and vegetation performance test, so that the defect of poor mechanical property of a raw soil material is overcome, the coordination of the strength and the vegetation performance of the vegetation cement soil is ensured, and the quality of the vegetation cement soil is improved. Therefore, the safety and carbon sequestration capacity of the vegetation type immature soil building after construction are guaranteed, transformation and upgrading of the building material industry and green and sustainable development of the building industry are facilitated, and wide market prospects are achieved.

Description

Technical Field

[0001] The present invention relates to the field of civil engineering, and in particular to a vegetation cement soil material for 3D printing and a proportioning method thereof. Background Art

[0002] In order to achieve the dual carbon goals and promote the transformation and upgrading of the building materials industry, with the introduction of green buildings and sustainable development concepts, the application of 3D printed vegetation-based earth building technology in the construction field has gradually attracted attention. 3D printed vegetation-based earth buildings have good environmental protection, representing the positive response of the construction field to environmental protection, sustainability and intelligence, and are an ideal building form that meets the development trends and needs of the future construction industry.

[0003] However, raw soil, which is the main building material, has relatively weak mechanical properties and seismic resistance. Existing 3D printed vegetation-based raw soil buildings simply use raw soil as the basic printing material, focusing only on its vegetation performance while ignoring the strength and durability requirements of the building.

[0004] The present invention aims to study the coordinated modification method of soil material strength and vegetation performance, to solve the shortcomings of soil building materials such as poor mechanical properties and insufficient seismic resistance, and proposes a new type of low-carbon vegetation cement soil building material, which is modified with multiple materials to improve the comprehensive performance of 3D printed vegetation-type soil buildings. Summary of the invention

[0005] The present invention aims to solve the key problem of the coordinated modification method of raw soil material strength and vegetation performance. Under the premise of meeting the corresponding mechanical performance requirements, the raw soil material is modified for strength; at the same time, its vegetation performance is studied. After modification, the raw soil material still needs to meet the plant growth conditions and be suitable for vegetation operations.

[0006] To achieve the above object, the present invention proposes a method for mixing cement soil for vegetation using cement and ferrous sulfate for modification. Compared with raw soil, the strength of the cement soil material prepared by the ratio is significantly improved and good vegetation properties are maintained. The present invention achieves the above object through the following technical solutions:

[0007] According to an embodiment of the present invention, a plant-growing cement soil material for 3D printing includes: raw soil, which comes from the original ecological soil of the mountains in Sichuan, has a moisture content of 18%, a pH value of 5.13, and is slightly acidic black soil; cement, which is ordinary Portland cement, with a pH value of 12.44; ferrous sulfate, which is ferrous sulfate heptahydrate crystals, with a pH value of 2.36; pure water, which is deionized ultrapure water, with a pH value of 7; and plant seeds, which can be selected from forage grass seeds such as Elymus salsa, ryegrass, bluegrass, tall fescue, and alfalfa. The mass ratio of each component is raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.087: 0.441: 0.091.

[0008] According to an embodiment of the present invention, a vegetation cement soil material for 3D printing needs to meet the requirements of strength and vegetation performance, and its performance measurements include compressive strength, pH value and vegetation performance.

[0009] In some embodiments of the present invention, the compressive strength test method of the vegetation cement soil material is to perform an unconfined compressive strength test, comprising the following steps:

[0010] S11. Prepare test samples: Prepare standard-sized cement-soil specimens, usually 70.7 mm × 70.7 mm × 70.7 mm standard cubic cement-soil specimens. The prepared specimens need to be placed under standard curing conditions at room temperature of 20°C ± 2°C for 14 days;

[0011] S12. Determine the performance of the test sample: Place the test piece on a universal test press, ensure that the pressure-bearing surface of the test piece is perpendicular to the top surface during molding, align the center of the test piece with the center of the lower pressure plate of the test machine, and continuously load at a loading rate of 4 mm / min until the test piece is destroyed;

[0012] S13. Data processing: During the test, record the maximum pressure value when the specimen is destroyed. Calculate the compressive strength of the vegetation cement soil based on the recorded pressure value and the cross-sectional area of ​​the specimen. Usually, the arithmetic mean of the measured values ​​of the three specimens is used as the strength value of the group of specimens to obtain the performance index of the vegetation cement soil and judge whether the quality of the vegetation cement soil meets the standards.

[0013] In some embodiments of the present invention, cement is first used to modify the raw soil material. Three types of cement, ordinary Portland cement, magnesium phosphate cement, and sulphoaluminate cement, are selected, and the dosage is 10%, 20%, 30%, and 40% of the soil content. Standard cubic cement soil specimens of 70.7mm×70.7mm×70.7mm are made, and unconfined compressive strength tests are carried out to study the improvement effect and modification law of different types of cement with different dosages on the strength of raw soil. Ordinary Portland cement has the most significant improvement effect, and the compressive strength of the specimen increases with the increase of cement dosage; sulphoaluminate cement has the second best improvement effect, and the compressive strength of the specimen also increases with the increase of cement dosage; magnesium phosphate cement has the worst improvement effect, and there is no obvious modification law. According to the unconfined compressive strength test data, the mass ratio of raw soil, cement, and pure water is selected as raw soil: cement: pure water = 1:0.3:0.441.

[0014] In some embodiments of the present invention, the pH value test method of the vegetation cement soil material is to determine the soil pH value by potentiometric method, comprising the following steps:

[0015] S21. Prepare the test sample: weigh 10.0 g of the vegetation cement soil sample and place it in a beaker, add 25 mL of water, stir vigorously for 2 min, let stand for 30 min, and complete the measurement within 1 h;

[0016] S22. Calibrate the pH meter: first calibrate with pH 6.86 (25°C) standard buffer solution, then calibrate with pH 9.18 (25°C) standard buffer solution, and adjust the instrument reading to be consistent with the pH value of the standard buffer solution;

[0017] S23. Determine the pH value of the test sample: control the sample temperature to 25℃±1℃, insert the electrode into the sample suspension, gently shake the sample, and record the pH value after the reading stabilizes. After the measurement, rinse the electrode immediately with water and absorb the water outside the electrode with filter paper before measuring the next sample.

[0018] In some embodiments of the present invention, ferrous sulfate is applied to the cement soil modified by cement alone, and the pH value of the cement soil is continuously adjusted to be suitable for plant growth until the pH is adjusted to about 7. First, the improvement effect of ferrous sulfate on the pH value of cement is explored, and 8 groups of control variable experiments are set up. The variables are the ratio of cement mass to ferrous sulfate mass, which are 1:2, 1:1.5, 1:1, 1:0.7, 1:0.5, 1:0.3, 1:0.1, and 1:0, respectively. When the ratio of cement mass to ferrous sulfate mass is 1:0.5, the pH value of cement is close to 7, which proves that ferrous sulfate can significantly improve the pH value of alkaline soil, and the pH value of cement decreases with the increase of ferrous sulfate dosage. Then, the effect of ferrous sulfate on the improvement of the pH value of cement soil for vegetation was explored. Five groups of controlled variable experiments were set up. The variables were the mass ratios of raw soil, cement and ferrous sulfate, which were 1:0.3:0.06, 1:0.3:0.075, 1:0.3:0.087, 1:0.3:0.09 and 1:0.3:0.15 respectively. When the mass ratio of raw soil, cement and ferrous sulfate was 1:0.3:0.087, the pH value of cement soil for vegetation was closest to 7. Therefore, the cement soil for vegetation ratio when the pH value of raw soil was 5 could be selected. The mass ratio of each component was raw soil: cement: ferrous sulfate: pure water = 1:0.3:0.087:0.441.

[0019] In some embodiments of the present invention, the method for testing the vegetation performance of the vegetation cement soil material is a vegetation test, which observes the growth conditions of plant seeds in the vegetation cement soil and judges the vegetation performance of the vegetation cement soil based on two performance indicators: germination rate and plant height.

[0020] According to an embodiment of the present invention, a method for mixing cement soil for planting achieves optimization of its strength and planting performance by adjusting the ratio of each component in the raw material of cement soil for planting. The modified ratio calculation formula of raw soil raw materials with different pH values ​​is: the molecular weight of raw soil is 80, the molecular weight of cement is 515, and the molecular weight of ferrous sulfate is 152. Assuming the pH value of raw soil is a, the mass of raw soil is m1, the mass of cement is 0.3m1, the mass of ferrous sulfate is m2, and the mass of pure water is 0.441m1, then [H + ] 生土 =10 -a mol / L, [H + ] 水泥 =10 -2 mol / L, [OH - ]=10 -2 mol / L, according to Available It can be solved The mass of each component required to configure the vegetation cement soil material is, m 生土 =m1,m 水泥=0.3m1,m 硫酸亚铁 =nm1,m 纯净水 =0.441m1. The present invention suggests that when the pH value of the raw soil is 4, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.0687: 0.441: 0.091; when the pH value of the raw soil is 5, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.0855: 0.441: 0.091; when the pH value of the raw soil is 6, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.0872: 0.441: 0.091; when the pH value of the raw soil is 7, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.0874: 0.441: 0.09 1; when the pH value of the raw soil is 8, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.0876: 0.441: 0.091; when the pH value of the raw soil is 9, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.0893: 0.441: 0.091; when the pH value of the raw soil is 10, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.1061: 0.441: 0.091; when the pH value of the raw soil is 11, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.2748: 0.441: 0.091.

[0021] According to an embodiment of the present invention, a method for mixing cement soil for planting comprises the following steps:

[0022] S1, selecting raw soil for preparing cement soil for vegetation and measuring the pH value of the raw soil raw material;

[0023] S2. Determine the mass ratio of each raw material component, namely, raw soil, cement, ferrous sulfate, purified water, and plant seeds according to the modified ratio calculation formula;

[0024] S3. Add corresponding amounts of cement, ferrous sulfate, purified water and plant seeds into the raw soil and mix well.

[0025] The present invention, a vegetated cement-soil material for 3D printing and a proportioning method thereof, studies a coordinated modification method of raw soil material strength and vegetative performance, solves the shortcomings of raw soil building materials such as poor mechanical properties and insufficient seismic resistance, and can make more full use of raw soil, a material with abundant resource reserves and environmental friendliness, thereby reducing the construction industry's dependence on limited resources and emission-intensive materials such as cement, promoting the transformation and upgrading of the traditional construction industry, and better promoting the realization of dual carbon goals. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Please refer to the attached drawings for detailed implementation of the present invention, in which: Figure 1 The present invention is a flow chart of the steps of the cement-soil mixing method for vegetation. DETAILED DESCRIPTION

[0027] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0028] See also Figure 1 A method for mixing cement soil for planting comprises the following steps:

[0029] S1, selecting raw soil for preparing cement soil for vegetation and measuring the pH value of the raw soil raw material;

[0030] S2. Determine the components of the raw materials according to the modified ratio calculation formula. Assume that the pH value of the raw soil is a, the mass of the raw soil is m1, the mass of the cement is 0.3m1, the mass of ferrous sulfate is m2, and the mass of pure water is 0.441m1, then [H + ] 生土 =10 -a mol / L, [H + ] 水泥 =10 -2 mol / L, [OH - ]=10 -2 mol / L, according to Available It can be solved The mass of each component required to configure the vegetation cement soil material is, m 生土 =m1,m 水泥 =0.3m1,n 硫酸亚铁 =nm1,m 纯净水=0.441m1; the present invention suggests that when the pH value of the raw soil is 4, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.0687: 0.441: 0.091; when the pH value of the raw soil is 5, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.0855: 0.441: 0.091; when the pH value of the raw soil is 6, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.0872: 0.441: 0.091; when the pH value of the raw soil is 7, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.0874: 0.441 : 0.091; when the pH value of the raw soil is 8, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.0876: 0.441: 0.091; when the pH value of the raw soil is 9, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.0893: 0.441: 0.091; when the pH value of the raw soil is 10, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.1061: 0.441: 0.091; when the pH value of the raw soil is 11, the mass ratio of each component is, raw soil: cement: ferrous sulfate: pure water: plant seeds = 1: 0.3: 0.2748: 0.441: 0.091;

[0031] S3. Add corresponding amounts of cement, ferrous sulfate, purified water and plant seeds into the raw soil and mix well.

Claims

1. A planted cement soil material for 3D printing, characterized in that: include: Raw soil, cement, ferrous sulfate, purified water, plant seeds, the mass ratio of each component is: Raw soil: Cement: ferrous sulfate: pure water: plant seeds = 1:0.3:0.087:0.441:0.

091.

2. The vegetation cement soil material for 3D printing according to claim 1, characterized in that: The raw soil used is black soil with a moisture content of 18% and a slightly acidic pH of 4.5-5.

5. The cement uses 42.5 ordinary Portland cement. The ferrous sulfate uses 29% concentration solution of ferrous sulfate heptahydrate with a pH of 2-3. The purified water uses deionized ultrapure water. The plant seeds can be seeds of forage grasses such as Elymus salsa, ryegrass, Poa annua, tall fescue, and alfalfa.

3. The vegetation cement soil material for 3D printing according to claim 1, characterized in that: Performance tests to be carried out include compressive strength, pH value and vegetation performance.

4. The vegetation cement soil material for 3D printing according to claim 3, characterized in that: The compressive strength test method is to conduct an unconfined compressive strength test, including the following steps: S11. Prepare test samples: Prepare standard-sized cement-soil specimens, usually 70.7 mm × 70.7 mm × 70.7 mm standard cubic cement-soil specimens. The prepared specimens need to be placed under standard curing conditions at room temperature of 20°C ± 2°C for 14 days; S12. Determine the performance of the test sample: Place the test piece on a universal test press, ensure that the pressure-bearing surface of the test piece is perpendicular to the top surface during molding, align the center of the test piece with the center of the lower pressure plate of the test machine, and continuously load at a loading rate of 4 mm / min until the test piece is destroyed; S13. Data processing: During the test, record the maximum pressure value when the specimen is destroyed. Calculate the compressive strength of the vegetation cement soil based on the recorded pressure value and the cross-sectional area of ​​the specimen. Usually, the arithmetic mean of the measured values ​​of the three specimens is used as the strength value of the group of specimens to obtain the performance index of the vegetation cement soil and judge whether the quality of the vegetation cement soil meets the standards.

5. The vegetation cement soil material for 3D printing according to claim 3, characterized in that: The pH test method is to determine the soil pH value by potentiometric method, which includes the following steps: S21. Prepare the test sample: weigh 10.0 g of the vegetation cement soil sample and place it in a beaker, add 25 mL of water, stir thoroughly for 2 min, let stand for 30 min, and complete the measurement within 1 h; S22. Calibrate the pH meter: first calibrate with pH 6.86 (25°C) standard buffer solution, then calibrate with pH 9.18 (25°C) standard buffer solution, and adjust the instrument reading to be consistent with the pH value of the standard buffer solution; S23. Determine the pH value of the test sample: control the sample temperature to 25℃±1℃, insert the electrode into the sample suspension, gently shake the sample, and record the pH value after the reading stabilizes. After the measurement, rinse the electrode immediately with water and absorb the water outside the electrode with filter paper before measuring the next sample.

6. The vegetation cement soil material for 3D printing according to claim 3, characterized in that: The vegetation performance test method is a vegetation test, which observes the growth of plant seeds and judges the vegetation performance of cement soil based on two performance indicators: germination rate and plant height.

7. A method for mixing cement soil for planting, characterized in that: Optimize the raw material ratio and optimize its strength and vegetation performance by adjusting the proportion of each component in the vegetation cement soil raw materials.

8. The method for mixing cement soil for vegetation according to claim 7, characterized in that: The calculation formula for the modified ratio of raw soil with different pH values ​​is given: Assuming the pH value of the raw soil is a, the mass of the raw soil is m1, the mass of cement is 0.3m1, the mass of ferrous sulfate is m2, and the mass of pure water is 0.441m1, then [H + ] Raw soil = 10 -a mol / L, [H + ] Cement = 10 -2 mol / L, [OH - ]=10 -2 mol / L, according to Available It can be solved The mass of each component required to configure the vegetation cement soil material is, m 生土 =m1,m 水泥 =0.3m1,m 硫酸亚铁 =nm1,m 纯净水 =0.441m1.

9. The method for mixing cement soil for vegetation according to claim 7, comprising the following steps: S1, selecting raw soil for preparing cement soil for vegetation and measuring the pH value of the raw soil raw material; S2. Determine the mass ratio of each raw material component, namely, raw soil, cement, ferrous sulfate, purified water, and plant seeds according to the modified ratio calculation formula; S3. Add corresponding amounts of cement, ferrous sulfate, purified water and plant seeds into the raw soil and mix well.

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