A method for preparing plant fiber toughened mortar

Abstract

The present invention discloses a method for preparing plant fiber toughened mortar, which comprises the following steps: S1. Cement, ordinary sand, fly ash, silica fume, and mineral powder are stirred and mixed to obtain dry materials; S2. The dry materials are mixed with plant fibers, and then water is added and stirred to obtain plant fiber toughened mortar; wherein: the plant fibers need to be pre-sprayed with water before being stirred and mixed with the dry materials and water; the pre-sprayed water amount of the plant fibers is denoted as C, and C = M B (K - T); in the formula: M B is the mass of the plant fibers after being dried to constant weight at 103 ± 2 °C; K represents the water saturation rate of the plant fibers, and T represents the moisture content of the plant fibers in different humidity and temperature environments. When designing the plant fiber toughened cement mortar, the method of the present invention determines the additional water amount required according to the dosage of the plant fibers to ensure that the effective water-cement ratio is not changed and the fluidity of the mortar is not affected.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of plant fiber mortar, and particularly relates to a method for preparing plant fiber toughened mortar. Background Art

[0002] Cement-based materials are the most widely used building materials in the world at present, but they are brittle materials and prone to cracking. Research shows that fibers have a good control effect on the cracking of cement-based materials. Steel fibers and synthetic fibers can improve the toughness of concrete to a certain extent, but at the same time increase the cost of concrete. Plant fibers are widely sourced, inexpensive, environmentally friendly, and have mechanical properties comparable to synthetic fibers. They can be used to replace chemical synthetic fibers and mineral fibers to toughen cement-based composites and inhibit the generation and expansion of cracks in water products.

[0003] However, there are the following problems when directly using plant fibers: (1) When plant fibers are incorporated into cement paste, they will absorb a large amount of mixing water, resulting in a significant reduction in the fluidity of the cement paste, easily introducing defects such as large pores, and reducing the strength of the cured cement matrix; (2) Directly incorporating plant fibers into cement paste will also affect the water-cement ratio, which is a key factor affecting the strength of hardened cement mortar and a key parameter for designing the mix ratio of cement-based composites. After different water-containing states of plant fibers (mainly affected by air humidity, temperature, etc.) are added to the cement matrix, due to the unknown water content and water absorption of plant fibers, the effective water-cement ratio in the composite system will be affected, increasing the difficulty of mix ratio design. The mix ratio design of concrete is a process of continuous adjustment, which needs to be adjusted according to the situation of trial mixing; among them, the water consumption is a key parameter, which determines the fluidity and strength. If the incorporated fibers do not absorb water or the water absorption rate is known, the mix ratio of concrete can be iteratively designed; in fact, there are many factors affecting the water absorption rate of plant fibers, and its water absorption rate is unknown, so the mix ratio of concrete cannot be iteratively designed, increasing the difficulty of mix ratio design.

[0004] At present, most of the methods for preparing "plant fiber cement-based composites" are mainly as follows: (1) Without considering the water absorption of plant fibers, simply add plant fibers to the cement mixture and stir. Due to the water absorption of plant fibers, this will inevitably lead to a significant reduction in the fluidity of the cement paste, affecting the strength of the cement matrix. The water absorption of the fibers reduces the effective water-cement ratio, and the degree of reduction varies depending on the fiber type, dosage, and moisture content, making it impossible to ensure the achievement of the designed strength and durability. (2) First, weigh the plant fibers according to the mix ratio, then soak the fibers in water, simply drain the water after they are saturated, or dry them with a rag, and then stir the plant fibers with other materials such as cement, sand, and gravel. The disadvantage of this method is that only simple drainage is carried out, and a large amount of free water will still adhere to the surface of the plant fibers, bringing extra moisture to the mixture, increasing the water-cement ratio; moreover, the standard for draining water is not unified, it takes a long time, and the impact on the mixture during each mixing is also unknown, which is not conducive to the iterative design of the mix ratio. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing plant fiber toughened mortar in view of the deficiencies of the existing methods, which solves the above problems; when designing the plant fiber toughened cement mortar of the present invention, according to the dosage of plant fibers, the amount of additional water to be added is determined to ensure that the effective water-cement ratio is not changed and the fluidity of the mortar is not affected.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for preparing plant fiber toughened mortar, characterized in that the method comprises the following steps:

[0008] S1. Stir and mix cement, ordinary sand, fly ash, silica fume, and mineral powder to obtain dry materials;

[0009] S2. Mix the dry materials with plant fibers, and then add water and stir to obtain plant fiber toughened mortar;

[0010] Wherein: the plant fibers need to be pre-sprayed with water and then stirred and mixed with the dry materials and water; the pre-sprayed water volume of the plant fibers is denoted as C, and C = M B (K - T);

[0011] In the formula: M B is the mass of the plant fibers after being dried to constant weight at 103 ± 2 °C; K represents the saturation water content rate of the plant fibers, and T represents the moisture content rate of the plant fibers at different humidity and temperature.

[0012] Specifically, the saturation water content rate (K) of the plant fibers is equivalent to the moisture content rate (T) of the plant fibers in the saturated surface dry state.

[0013] Further, a method for preparing plant fiber toughened mortar: The dry materials described in step S1 include the following components in parts by weight:

[0014] 1 part of cement, 0.5 - 3.0 parts of ordinary sand, 0.1 - 0.3 parts of fly ash, 0.05 - 0.1 parts of silica fume, and 0.1 - 0.3 parts of mineral powder.

[0015] Furthermore, a method for preparing plant fiber toughened mortar: The addition amount of the plant fiber described in step S2 is 0.02 - 0.1 part; the addition amount of the water is 40 - 80% of the total amount of cement, fly ash, and mineral powder.

[0016] Further, a method for preparing plant fiber toughened mortar: The plant fiber is selected from any one of sisal fiber, coconut shell fiber, and ramie fiber.

[0017] Further, a method for preparing plant fiber toughened mortar: The test method for the water saturation rate (K) of the plant fiber includes the following steps:

[0018] (1) Cut the plant fiber, and immerse the cut plant fiber in water to absorb water until saturated.

[0019] (2) Take out the water-saturated plant fiber, and centrifuge the plant fiber multiple times to remove free water until it reaches the saturated surface dry state.

[0020] (3) Weigh the mass of the plant fiber when it reaches the saturated surface dry state, denoted as M A ;

[0021] (4) Then dry the above-mentioned plant fiber in the saturated surface dry state at 103 ± 2 °C until the mass is constant, denoted as M B ;

[0022] (5) Calculate the water saturation rate K of the plant fiber; the calculation formula is: K = (M A - M B ) / M B .

[0023] Further, a method for preparing plant fiber toughened mortar: The test method for the water saturation rate (K) of the plant fiber, the test method includes the following steps: In step (1), the length of the cut plant fiber is 15 - 25 mm; the water absorption saturation time of the plant fiber is 2 - 5 hours.

[0024] Further, a method for preparing plant fiber toughened mortar: The test method for the water saturation rate (K) of the plant fiber includes the following steps: The first centrifugation rate in step (2) is 300 - 500 rpm, and each subsequent centrifugation increases the rate by 300 - 500 rpm based on the previous centrifugation rate until no free water is produced.

[0025] The purpose of setting the increasing rotation speeds for multiple centrifugations in the present invention is to save centrifugation energy. After the plant fiber is saturated with water, most of the free water can be removed in a short time at a relatively low rotation speed. By gradually increasing the centrifugation rate, a small amount of free water is separated successively until no new free water is produced in the centrifuge tube.

[0026] The specific centrifugation process is as follows: After the plant fiber is saturated with water, wrap the plant fiber with gauze and fix the gauze-wrapped plant fiber in the centrifuge tube; the fixation is to tighten the edge of the gauze on the centrifuge tube with the lid of the centrifuge tube (as Figure 1 shown); the rotation speeds for multiple centrifugations increase successively until no free water is produced in the centrifuge tube. A schematic diagram of the free water produced after placing the plant fiber in the centrifuge tube and centrifuging is as Figure 1 shown.

[0027] Further, a method for preparing plant fiber toughened mortar: The test method for the water content rate (T) of the plant fiber includes the following steps: Step (4) drying the plant fiber in a forced air drying oven; wherein: the drying temperature is 103 ± 2 °C, measuring the mass of the plant fiber every 2 - 4 hours, and ending the drying when the mass difference between two measurements ≤ 0.1 g.

[0028] Further, a method for preparing plant fiber toughened mortar: The test method for the water content rate (T) of the plant fiber includes the following steps:

[0029] (1) Add sulfuric acid solutions with different concentrations to multiple drying containers to simulate different relative humidity environments;

[0030] (2) Then place the above-mentioned multiple containers in different temperature environments respectively;

[0031] (3) Let plant fibers with a mass of M B stand in the above-mentioned containers with different relative humidities and different temperatures respectively. After the mass of the plant fiber is stable under the corresponding humidity and temperature environments, measure the mass of the plant fiber under the combined conditions of this humidity and temperature, and record it as M C ;

[0032] Note: When placing the plant fiber in the containers under each combined condition, the plant fiber does not contact the sulfuric acid solution in the container;

[0033] (4) Calculate the moisture content T of the plant fiber; the calculation formula is: T = (M C − M B ) / M B .

[0034] Furthermore, a method for preparing plant fiber toughened mortar: the test method for the moisture content (T) of the plant fiber: repeat the operation, test the mass of the plant fiber under multiple combinations of humidity and temperature conditions, and record the corresponding mass of the plant fiber under each combination condition; thereby calculate the moisture content of the plant fiber under various humidity and temperature conditions, and tabulate and summarize the corresponding data.

[0035] The method provided by the present invention for each type of plant fiber, before use, first take a partial sample, and then test its water saturation rate (K) and moisture content (T) under different temperature and humidity conditions.

[0036] Advantages of the present invention:

[0037] (1) The present invention adopts a quaternary cementitious system of "cement - fly ash - slag - silica fume", which is beneficial to consuming the hydration product calcium hydroxide, reducing the alkalinity of the cement matrix, helping to weaken the erosion of the alkaline cement matrix on the plant fiber, and being beneficial to the early strength.

[0038] (2) The method of the present invention can take a small amount of sample as a representative sample, conduct a centrifugal dehydration experiment on it, measure its water saturation rate (i.e., the moisture content in the saturated surface dry state), and then measure its moisture content under different temperature and humidity conditions, and make a table; then when using this plant fiber subsequently, the moisture content of this plant fiber at different temperatures and humidities can be directly looked up in the table, and then according to its water saturation rate and moisture content, it can be calculated how much additional water (i.e., the pre-sprayed water volume C) this plant fiber will absorb after being added to the cement matrix. Spray this part of the additional absorbed water onto the plant fiber before mixing, so that neither will the mixing water of the cement matrix be absorbed due to the addition of the plant fiber, resulting in a significant reduction in the fluidity of the cement paste, nor will it bring excess water to the cement paste, increasing the water-cement ratio. When designing the mix proportion of the present invention, the additional water volume to be added is determined according to the dosage of the plant fiber to ensure that the effective water-cement ratio is not changed and the fluidity of the mortar is not affected.

[0039] (3) The method of the present invention is convenient, fast and once and for all. After tabulating, each time this plant fiber is used, the moisture content can be obtained by looking up the table, the sprayed water volume is obtained through simple calculation, and the corresponding sprayed water volume is sprayed onto the plant fiber, without the need to go through time-consuming processes such as soaking and draining water; at the same time, the method of the present invention can accurately characterize the water absorption of the plant fiber, minimizing the complexity of the mix proportion design to the greatest extent. Compared with the water draining and wiping methods mentioned in the background technology, the method of the present invention is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] Figure 1 It is an operation diagram for centrifuging plant fibers to reach saturated surface dryness. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, rather than all, of the embodiments of the present invention. The following description of at least one exemplary embodiment is merely illustrative and in no way limits the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0043] Embodiment 1

[0044] A method for preparing plant fiber toughened mortar, characterized in that the method comprises the following steps:

[0045] S1. Stir and mix 1 part of cement, 0.2 part of fly ash, 0.2 part of slag powder, and 0.08 part of silica fume evenly to obtain a "cement - fly ash - slag powder - silica fume" quaternary cementitious material. Then, lay the above quaternary cementitious material and ordinary sand in a layer of cementitious material and a layer of ordinary sand in a stirrer, and after laying, stir and mix to obtain dry materials; wherein: the total amount of ordinary sand is 0.5 part;

[0046] S2. Add the above dry materials and plant fibers (sisal fibers) in a "small amount and multiple times" manner while stirring to mix the plant fibers, and then add water and stir to obtain plant fiber toughened mortar; wherein: the total added amount of sisal fibers is 0.04 part; the added amount of water is 60% of the total weight of cement, fly ash, and slag powder;

[0047] Wherein: the sisal fibers need to be pre-absorbed with water before mixing with the dry materials, and then stirred and mixed with the dry materials and water; the pre-sprayed water amount of the sisal fibers is denoted as C, and C = M B (K - T);

[0048] In the formula: M Bis the mass of the sisal fiber after drying to a constant weight at 105°C; K represents the saturated water content rate of the sisal fiber, and T represents the moisture content of the sisal fiber in different humidity and temperature environments;

[0049] Specifically, the test method for the saturated water content rate (K) of the above sisal fiber includes the following steps:

[0050] (1) Take a sample of the sisal fiber, then cut it, cut it into a length of 20 mm, and then immerse the cut sisal fiber in water for water absorption saturation for 3 hours;

[0051] (2) Take out the water-saturated sisal fiber, and then centrifuge the sisal fiber multiple times to remove free water to reach the saturated surface dry state; where: the first centrifugation rate is 500 rpm, the centrifugation time is 10 minutes, and then centrifuge for the second time at a rate of 1000 rpm for 10 minutes; thereafter, each centrifugation increases by 500 rpm based on the previous centrifugation rate until no more free water is produced and the sisal fiber reaches the saturated surface dry state;

[0052] (3) Weigh the mass of the sisal fiber when it reaches the saturated surface dry state, and record it as M A ;

[0053] (4) Then place the above sisal fiber in the saturated surface dry state in a blast drying oven and dry it to a constant mass at 105°C, and record it as M B ; Specifically, test the mass of the sisal fiber every 3 hours, and end the drying when the mass difference measured twice ≤ 0.1 g;

[0054] (5) Calculate the saturated water content rate K of the plant fiber; the calculation formula is: K = (M A - M B ) / M B ;

[0055] Specifically, the test method for the moisture content (T) of the above sisal fiber includes the following steps:

[0056] (1) Add sulfuric acid solutions with different concentrations to multiple drying containers to simulate different relative humidity environments;

[0057] (2) Then place the above multiple containers in different temperature environments respectively;

[0058] (3) Place sisal fibers with a mass of M B in the above containers with different relative humidities and different temperatures respectively and let them stand still. After the mass of the sisal fiber becomes stable in the corresponding "humidity and temperature" environment, test the mass of the sisal fiber under the combined conditions of this "humidity and temperature", and record it as M C;Repeat the operation, test the quality of sisal fiber under multiple "humidity and temperature" combination conditions, and record the corresponding quality of sisal fiber under each combination condition; calculate the moisture content of sisal fiber under various humidity and temperature conditions based on this, and tabulate and summarize the corresponding data; in the future, when using this sisal fiber, you can directly look up the table to know the moisture content of the fiber under specific "humidity and temperature" conditions;

[0059] Note: Place the sisal fiber in a container under various "humidity and temperature" combination conditions, but do not contact the sulfuric acid solution in the container to simulate the actual placement environment of the sisal fiber;

[0060] (4) Calculate the moisture content T of the plant fiber; the calculation formula is: T = (M C - M B ) / M B ; From this, it can be obtained that M C = M B (1 + T), that is, M B = M C / (1 + T); Therefore, according to the calculation formula of the pre-absorbed water volume C (i.e., the additional water volume required): C = M B (K - T); it can be deduced that C = M C (K - T) / (1 + T).

[0061] It can be seen from the above-mentioned Example 1 that the method of the present invention only needs to rely on the moisture content (T) data table of sisal fiber under various "humidity and temperature" conditions to obtain the moisture content result of the sisal fiber, and then the additional water volume (C) required for adding sisal fiber with a mass of M C can be calculated according to the formula; the method of the present invention is simple and direct, fast and convenient, and can ensure that when the plant fiber is added to the cement slurry for mixing, it will neither bring extra moisture to the matrix nor absorb the moisture in the original cement slurry, ensuring that the effective water-cement ratio is not changed and the fluidity of the mortar is not affected.

[0062] Specifically, these additional water volumes required (pre-sprayed water volume C) can be sprayed on the sisal fiber in advance with the corresponding amount of water before mixing the sisal fiber with the dry material, and then mix and stir with the dry material after it is all absorbed; or mix and stir the corresponding amount of water with the original amount of water to be added together with the sisal fiber and the dry material.

[0063] Example 2

[0064] Example 2 is different from Example 1 in that: the dry materials in Example 2 include the following components in parts by weight: 1 part of cement, 3.0 parts of ordinary sand, 0.3 part of fly ash, 0.1 part of silica fume, and 0.3 part of slag powder; the plant fiber in Example 2 is coconut shell fiber, and the addition amount of coconut shell fiber is 0.1 part; the addition amount of water in Example 2 is 80% of the total amount of cement, fly ash, and slag powder. The water absorption saturation time in Example 2 is 2 hours; the first centrifugation rate is 300 rpm, and the centrifugation rate increases by 400 rpm each time thereafter; the drying temperature in Example 2 is 101 °C, and the remaining conditions in Example 2 are the same as those in Example 1.

[0065] Example 3

[0066] Example 3 is different from Example 1 in that: the dry materials in Example 3 include the following components in parts by weight: 1 part of cement, 1.5 parts of ordinary sand, 0.1 part of fly ash, 0.05 part of silica fume, and 0.1 part of slag powder; the plant fiber in Example 3 is ramie fiber, and the addition amount of ramie fiber is 0.02 part; the addition amount of water in Example 3 is 40% of the total amount of cement, fly ash, and slag powder. The water absorption saturation time in Example 3 is 5 hours; the first centrifugation rate is 400 rpm, and the centrifugation rate increases by 300 rpm each time thereafter; the drying temperature in Example 3 is 103 °C, and the remaining conditions in Example 3 are the same as those in Example 1.

[0067] Comparative Example 1

[0068] A method for preparing plant fiber toughened mortar is provided, which is characterized in that the method includes the following steps:

[0069] S1. Cut the sisal fiber into a length of 20 mm, and then immerse the cut sisal fiber in water for water absorption saturation. The water absorption saturation time is 3 hours;

[0070] S2. Take out the water absorption saturated sisal fiber, and then centrifuge the sisal fiber multiple times to remove free water to reach the saturated surface dry state; wherein: the first centrifugation rate is 500 rpm, the centrifugation time is 10 minutes, and then centrifuge for the second time at a rate of 1000 rpm for 10 minutes; each subsequent centrifugation increases the centrifugation rate by 500 rpm on the basis of the previous centrifugation rate until no free water is produced, so that the sisal fiber reaches the saturated surface dry state;

[0071] S3. Mix 1 part of cement, 0.2 part of fly ash, 0.2 part of slag powder, and 0.08 part of silica fume evenly to obtain a "cement - fly ash - slag powder - silica fume" quaternary cementitious material. Then, lay the above quaternary cementitious material and 0.5 part of ordinary sand in layers in a mixer in the way of one layer of gel material and one layer of ordinary sand. After laying, stir and mix to obtain dry materials;

[0072] S4. Add 0.04 part of sisal fiber in saturated surface dry state to the above dry materials and mix the plant fiber in the way of "a little at a time" while stirring, and then add water and stir to obtain plant fiber toughened mortar.

[0073] Analysis shows that: before adding sisal fiber into the cement slurry in Comparative Example 1 above, it was centrifugally dehydrated to reach the saturated surface dry state, so that the addition of sisal fiber would neither bring extra water to the cement slurry nor absorb water, without affecting the "effective water - cement ratio" and the fluidity of the mortar, making the proportioning more accurate and easy to adjust the proportioning iteration design according to the performance; however, it is not difficult to find that although this method in Comparative Example 1 can ensure an effective water - cement ratio, it requires procedures such as saturating the sisal fiber with water, centrifuging, and obtaining saturated surface dry fiber before each use. On the one hand, it consumes a large amount of energy required for centrifugation, and on the other hand, it seriously affects the efficiency. In the method of the present invention, during the subsequent actual use of plant fiber, only by referring to the water content data table of plant fiber under specific humidity and temperature conditions, the additional required water volume C can be accurately calculated, without the need to repeat procedures such as saturated water absorption and centrifugation, which is convenient, fast, simple and accurate, and can achieve the excellent effect of ensuring an effective water - cement ratio after adding plant fiber.

[0074] The method of the present invention is to first take some plant fiber samples, centrifuge - dry - and then balance at multiple humidities and temperatures to obtain the water contents under different humidity and temperature combinations. That is: knowing the saturation water content and water content; according to the humidity and temperature environment where the plant fiber is located during actual use, referring to the water content data in the table, the additional required water volume (i.e., the pre - spraying water volume C) for using this plant fiber can be directly and accurately calculated. When making the material proportioning, supplement these water volumes, which is more convenient and fast, and does not affect the mix ratio, ensuring that the effective water - cement ratio of the cement paste material will not be changed due to the addition of plant fiber, without affecting the fluidity of the mortar, and ensuring the mechanical properties of the cement matrix material after curing.

[0075] The above are the preferred embodiments of the present invention, which are only used to explain the present invention and are not used to limit the present invention. Any obvious changes or variations derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for preparing plant fiber toughened mortar, characterized in that, The method includes the following steps: S1. Mix cement, ordinary sand, fly ash, silica fume, and slag powder to obtain dry materials. S2. Mix the dry materials with plant fibers, and then add water and stir to obtain plant fiber toughened mortar. Wherein: the plant fiber needs to be pre-sprayed with water and then stirred and mixed with the dry material and water; the pre-sprayed water amount of the plant fiber is denoted as C, and C = M B (K - T); Where: M B is the mass of the plant fiber after being dried to a constant weight at 103 ± 2°C; K represents the water saturation rate of the plant fiber, and T represents the moisture content of the plant fiber at different humidity and temperature conditions.

2. The method for preparing plant fiber toughened mortar according to claim 1, characterized in that, The dry materials in step S1 include the following components in parts by weight: 1 part of cement, 0.5 - 3.0 parts of ordinary sand, 0.1 - 0.3 parts of fly ash, 0.05 - 0.1 parts of silica fume, and 0.1 - 0.3 parts of slag powder.

3. The method for preparing plant fiber toughened mortar according to claim 2, characterized in that, In step S2, the addition amount of the plant fiber is 0.02 - 0.1 part; the addition amount of the water is 40 - 80% of the total amount of cement, fly ash, and slag powder.

4. A method for preparing plant fiber toughened mortar according to claim 1, characterized in that, The plant fiber is selected from any one of sisal fiber, coconut shell fiber, and ramie fiber.

5. A method for preparing plant fiber toughened mortar according to claim 1, characterized in that, The test method for the water saturation rate (K) of the plant fiber includes the following steps: (1) Cut the plant fiber, and immerse the cut plant fiber in water to absorb water until saturated. (2) Take out the water-saturated plant fiber, and centrifuge the plant fiber multiple times to remove free water until it reaches the saturated surface dry state. (3) Weigh the mass of the plant fiber when it reaches the saturated surface dry state, and record it as M A ; (4) Then dry the above plant fibers in the saturated surface dry state at 103 ± 2 °C until the mass is constant, weigh its mass, and record it as M B ; (5) Calculate the water saturation rate K of the plant fiber. The calculation formula is: K = (M A - M B ) / M B .

6. A method for preparing plant fiber toughened mortar according to claim 5, characterized in that, In step (1), the length of the cut plant fiber is 15 - 25 mm; the water absorption saturation time of the plant fiber is 2 - 5 hours.

7. A method for preparing plant fiber toughened mortar according to claim 5, characterized in that, In step (2), the first centrifugation rate is 300 - 500 rpm, and each subsequent centrifugation increases by 300 - 500 rpm based on the previous centrifugation rate until no free water is produced.

8. A method for preparing plant fiber toughened mortar according to claim 5, characterized in that, In step (4), dry the plant fiber in a blast drying oven; where: the drying temperature is 103 ± 2 °C, measure the mass of the plant fiber every 2 - 4 hours, and end the drying when the mass difference measured twice ≤ 0.1 g.

9. A method for preparing plant fiber toughened mortar according to claim 1, characterized in that, The test method for the water content (T) of the plant fiber includes the following steps: (1) Add sulfuric acid solutions with different concentrations to multiple drying containers to simulate different relative humidity environments. (2) Then place the above multiple containers in different temperature environments respectively. (3) Leave the plant fiber with a mass of M B to stand still in the containers with the above different relative humidities and different temperatures. After the mass of the plant fiber is stable in the corresponding humidity and temperature environment, test the mass of the plant fiber under the combined conditions of this humidity and temperature, and record it as M C ; Note: When placing the plant fiber in the containers under various combined conditions, the plant fiber does not contact the sulfuric acid solution in the container. (4) Calculate the moisture content T of the plant fiber; the calculation formula is: T = (M C - M B ) / M B .

10. A method for preparing plant fiber toughened mortar according to claim 9, characterized in that, Repeat the operation, test the mass of the plant fiber under multiple combined conditions of humidity and temperature, and record the corresponding mass of the plant fiber under each combined condition; thereby calculate the water content of the plant fiber under various humidity and temperature conditions, and tabulate and summarize the corresponding data.

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