An evaluation method for the anti-penetration performance of fiber-reinforced cementitious materials

Abstract

The present invention relates to a method for evaluating the anti-penetration performance of fiber-reinforced cement-based materials, belonging to the technical field of performance testing of new building materials. The method includes the following steps: dividing the components of the fiber-reinforced cement-based material into multiple constituent phases; separately detecting the Rockwell hardness of each phase; calculating the equivalent length of each phase according to the volume ratio of each phase in the fiber-reinforced cement-based material; obtaining the effective hardness of the fiber-reinforced cement-based material by weighting according to the Rockwell hardness of each phase and the equivalent length of each phase; establishing the correlation between the effective hardness and the anti-penetration performance; calculating the effective hardness of the fiber-reinforced cement-based material with unknown anti-penetration performance and matching it with the obtained correlation to evaluate the anti-penetration performance of the fiber-reinforced cement-based material with unknown anti-penetration performance. The present invention can accurately characterize the anti-penetration performance of cement-based materials with different material compositions and complex properties when the corresponding relationship between the compressive strength and the anti-penetration performance fails.

Description

Technical Field

[0001] The present invention belongs to the technical field of physical property testing of new building materials, and relates to an evaluation method for the anti-penetration performance of fiber-reinforced cement-based materials. Background Art

[0002] Disclosing the information of this background art section is only intended to increase the understanding of the overall background of the present invention, and is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Compressive strength is one of the most important index parameters of cement-based materials such as concrete. For a long time, it has been considered that: the higher the compressive strength of the cement-based material, the better its anti-penetration performance, specifically manifested as the penetration depth of a high-speed projectile in the cement-based material gradually decreases with the increase of the compressive strength. In fact, the material composition, microstructure and crack propagation of the cement-based material all have varying degrees of influence on its anti-penetration performance. With the progress of concrete technology, the above-mentioned correlation between the anti-penetration performance and the compressive strength is no longer applicable to advanced cement-based materials such as ultra-high performance concrete (UHPC) and high ductility fiber-reinforced cement-based composites (ECC).

[0004] As Figure 1 shown, after the compressive strength exceeds a certain threshold (120 MPa), continuously increasing the compressive strength of the cement-based material cannot further reduce its penetration depth under the action of a high-speed projectile. For example, under the same penetration conditions, the normalized penetration depths of UHPC with a compressive strength of 160 - 210 MPa and concrete with a compressive strength of 90 - 110 MPa are equivalent. The compressive strength has lost its obvious correlation with the anti-penetration performance, and it is impossible to evaluate the strength of the anti-penetration performance by the numerical value of the compressive strength. Therefore, it is urgent to propose an evaluation method for the anti-penetration performance of cement-based materials that comprehensively considers the influence of material composition. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an evaluation method for the anti-penetration performance of fiber-reinforced cement-based materials, establish the connection between the Rockwell hardness value and the anti-penetration performance, and use the test results of Rockwell hardness to quickly evaluate the anti-penetration performance of cement-based materials.

[0006] To achieve the above purpose, the technical solution of the present invention is as follows:

[0007] An evaluation method for the anti-penetration performance of fiber-reinforced cement-based materials, comprising the following steps:

[0008] S1. Regarding the fiber-reinforced cement-based material as a multi-phase material, dividing each component of the fiber-reinforced cement-based material into multiple constituent phases;

[0009] S2. Obtain samples of all constituent phases and respectively measure the Rockwell hardness of each phase.

[0010] S3. Calculate the equivalent length of each phase according to the volume ratio of each phase in the fiber-reinforced cementitious material.

[0011] S4. Based on the Rockwell hardness of each phase obtained by detection in S2 and the equivalent length of each phase obtained in S3, obtain the effective hardness of the fiber-reinforced cementitious material by weighting.

[0012] S5. Detect the anti-penetration performance of fiber-reinforced cementitious materials with different components, and based on the effective hardness corresponding to the fiber-reinforced cementitious material obtained from S1 to S4, establish the correlation between the effective hardness and the anti-penetration performance.

[0013] S6. According to S1 to S4, calculate the effective hardness of the fiber-reinforced cementitious material with unknown anti-penetration performance, match it with the correlation obtained in S5, and evaluate the anti-penetration performance of the fiber-reinforced cementitious material with unknown anti-penetration performance.

[0014] Optionally, in S1, the fiber-reinforced cementitious material is regarded as a three-phase material composed of a mortar matrix phase, a coarse aggregate phase, and a fiber phase; the mortar matrix phase includes: cement, silica fume, fly ash, etc.; the coarse aggregate phase includes: rock aggregates with a particle size of 5 - 16 mm, and the fiber phase is: one or more of straight copper-plated steel fibers, hooked copper-plated steel fibers, and organic fibers.

[0015] Optionally, in S2, obtain samples of the fiber-reinforced cementitious material and measure the Rockwell hardness on the surface of the samples; obtain samples of the coarse aggregates in the fiber-reinforced cementitious material and measure the Rockwell hardness on the surface of the coarse aggregate samples; obtain samples of the fibers in the fiber-reinforced cementitious material and measure the Rockwell hardness of the fiber samples.

[0016] Optionally, in S3, based on the volume ratios of the mortar matrix phase, the coarse aggregate phase, and the fiber phase, obtain the equivalent length of the mortar matrix; obtain the equivalent length of the coarse aggregates; obtain the equivalent length of the fibers.

[0017] Optionally, the equivalent length of each phase in S3 is obtained by taking the cube root of the volume fraction of each phase; the equivalent length of the fiber phase is corrected according to the fiber type.

[0018] Optionally, in S4, in the weighted calculation method, the weight of each phase is equal to the ratio of the equivalent length of the phase to the sum of the equivalent lengths of all phases.

[0019] Optionally, in S5, the detected anti-penetration performance includes: normalized penetration depth and crater diameter; the correlation is a linear relationship.

[0020] Hardness refers to the ability of the material surface to resist plastic deformation caused by the indentation of a harder object, and it is an important index to measure the hardness of materials. Rockwell hardness is one of the commonly used hardness testing methods. Its principle is to use indenters with different shapes and sizes to conduct indentation tests on the surface of the specimen under a certain load, and determine the hardness value of the material by measuring the residual indentation depth of the indenter. Due to its simple operation, short test cycle, and little damage to the sample, Rockwell hardness is widely used in the field of material performance evaluation and other fields.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. The present invention proposes an evaluation method for the anti-penetration performance of cement-based materials that can comprehensively consider the influence of each constituent phase of the material, and establishes a new characterization method for the anti-penetration performance of cement-based materials based on Rockwell hardness. It can accurately characterize the anti-penetration performance (penetration depth and crater diameter) of cement-based materials with different material compositions and complex properties when the corresponding relationship between compressive strength and anti-penetration performance fails. Avoiding the previous dependence of cement-based materials on traditional penetration experiments to evaluate their anti-penetration performance, through the evaluation method provided by the present invention, not only can the anti-penetration performance of cement-based materials be quickly evaluated, but also due to its little damage to the specimen, the integrity of the specimen can be maintained, thereby improving the reliability and repeatability of the test.

[0023] 2. The present invention deeply analyzes the relationship between the microstructure and macroscopic properties of cement-based materials, and uses advanced material hardness testing technology to predict its anti-penetration performance. It is not only applicable to laboratory research, but also can be used for on-site rapid detection, providing convenience for material selection and quality control in engineering applications. In addition, through the optimization of the test process, the present invention significantly improves the detection efficiency, reduces the time and cost required for testing, and makes the evaluation of the anti-penetration performance of materials more economical and efficient.

[0024] 3. The present invention is not limited to cement-based materials, but can also be extended to the performance evaluation of other advanced engineering materials, enabling a more comprehensive understanding and utilization of the anti-penetration characteristics of materials, and providing strong technical support for the further research and development of material anti-penetration performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The specification drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0026] Figure 1 It is a schematic diagram showing the relationship between the normalized penetration depth and the compressive strength of cement-based materials in the background technology of the present invention;

[0027] Figure 2Schematic diagram of the effective length of the fiber-reinforced cementitious material in Embodiment 1 of the present invention;

[0028] Figure 3 Schematic diagram of the correlation between the normalized penetration depth and the effective hardness of the fiber-reinforced cementitious material in Embodiment 3 of the present invention;

[0029] Figure 4 Schematic diagram of the correlation between the crater diameter and the indentation depth of the fiber-reinforced cementitious material in Embodiment 3 of the present invention;

[0030] Figure 5 Schematic diagram of the effective length of the fiber-reinforced cementitious material in the comparative example of the present invention.

[0031] Among them, 1, bullet trajectory; 2, bullet; 3, mortar matrix phase; 4, coarse aggregate phase; 5, fiber phase. Detailed implementation manners

[0032] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further descriptions of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0033] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary implementation manners according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] An evaluation method for the anti-penetration performance of a fiber-reinforced cementitious material, comprising the following steps:

[0035] S1. Regarding the fiber-reinforced cementitious material as a multiphase material, dividing the components of the fiber-reinforced cementitious material into multiple constituent phases;

[0036] S2. Obtaining specimens of all constituent phases and respectively detecting the Rockwell hardness of each phase;

[0037] S3. Calculating the equivalent length of each phase according to the volume ratio of each phase in the fiber-reinforced cementitious material;

[0038] S4. Weighting to obtain the effective hardness of the fiber-reinforced cementitious material according to the Rockwell hardness of each phase detected in S2 and the equivalent length of each phase obtained in S3;

[0039] S5. Detect the anti-penetration performance of fiber-reinforced cementitious materials with different components, and obtain the corresponding effective hardness of the fiber-reinforced cementitious materials according to S1-S4, and establish the correlation between the effective hardness and the anti-penetration performance;

[0040] S6. According to S1-S4, calculate the effective hardness of fiber-reinforced cementitious materials with unknown anti-penetration performance, match it with the correlation obtained in S5, and evaluate the anti-penetration performance of fiber-reinforced cementitious materials with unknown anti-penetration performance.

[0041] Optionally, in S1, the fiber-reinforced cementitious material is regarded as a three-phase material composed of a mortar matrix phase, a coarse aggregate phase, and a fiber phase; the mortar matrix phase includes: cement, silica fume, fly ash, etc.; the coarse aggregate phase includes: rock aggregates with a particle size of 5-16 mm, and the fiber phase is one or more of straight copper-plated steel fibers, hooked copper-plated steel fibers, and organic fibers.

[0042] Optionally, in S2, obtain specimens of the fiber-reinforced cementitious material, and detect the Rockwell hardness of the specimen surface; obtain specimens of the coarse aggregate in the fiber-reinforced cementitious material, and detect the Rockwell hardness of the coarse aggregate specimen surface; obtain specimens of the fiber in the fiber-reinforced cementitious material, and detect the Rockwell hardness of the fiber specimen.

[0043] Optionally, in S3, obtain the volume ratios of the mortar matrix phase, the coarse aggregate phase, and the fiber phase, and obtain the equivalent length of the mortar matrix; obtain the equivalent length of the coarse aggregate; obtain the equivalent length of the fiber;

[0044] Optionally, the equivalent length of each phase in S3 is obtained by taking the cube root of the volume fraction of each phase; the equivalent length of the fiber phase is corrected according to the fiber type.

[0045] Optionally, the calculation method of the equivalent length of each phase in S3 is as follows:

[0046]

[0047] V_coarse aggregate + V_matrix + V_fiber = 100%;

[0048] Among them, V 粗骨料 is the volume ratio of the coarse aggregate phase in the fiber-reinforced cementitious material;

[0049] V 基体 is the volume ratio of the mortar matrix phase in the fiber-reinforced cementitious material;

[0050] V 纤维 is the volume ratio of the fiber phase in the fiber-reinforced cementitious material;

[0051] The value of k is selected according to the type of fiber. When the straight copper-plated steel fiber is used, k is taken as 1.0; when the hooked copper-plated steel fiber is used, k is taken as 1.2; when the organic fiber is used, k is taken as 0.9.

[0052] Optionally, in S4, in the weighted calculation method, the weight of each phase is equal to the ratio of the equivalent length of the phase to the sum of the equivalent lengths of all phases.

[0053] Optionally, in S4, the calculation method of the effective hardness H of the cement-based material is:

[0054]

[0055] where H 粗骨料 is the Rockwell hardness value of the coarse aggregate in the fiber-reinforced cement-based material;

[0056] H 基体 is the Rockwell hardness value of the mortar matrix in the fiber-reinforced cement-based material;

[0057] H 纤维 is the Rockwell hardness value of the fiber in the fiber-reinforced cement-based material.

[0058] Optionally, in S5, the detected anti-penetration performance includes: normalized penetration depth and crater diameter; the correlation is a linear relationship;

[0059] where the calculation method of the normalized penetration depth is: normalized penetration depth = penetration depth / impact velocity.

[0060] Optionally, the evaluation method of the normalized penetration depth Y 侵彻深度 is:

[0061] Y 侵彻深度 =-0.41H 有效 +45.004; R 2 =0.91;

[0062] The evaluation method of the crater diameter Y 开坑直径 is:

[0063] Y 开坑直径 =-0.513H 有效 +92.016; R 2 =0.80.

[0064] Example 1

[0065] The measurement method of the Rockwell hardness of each phase in the fiber-reinforced cement-based material includes the steps of:

[0066] Step 1. Pour the cement-based material to prepare a 100×100×100mm 3The cubic blocks are cured, polished and cleaned, and then straight lines perpendicular to the edges are drawn at equal intervals on their non-casting surfaces, dividing the non-casting surfaces into 25 square test areas of 20×20mm 2 ;

[0067] Each test block has four non-casting surfaces for inspection, and at least nine measuring points are selected for inspection on each casting surface; to avoid the influence of edge effects, the 16 outermost square test areas in contact with the edges are discarded, and the midpoints of the nine middle square areas are selected as the pressure measuring point areas,

[0068] Step 2: Use a Rockwell hardness tester to measure the Rockwell hardness of the test block. Select a steel ball with a diameter of 1.5875mm as the indenter, and select an initial test force of 29.42N and a total test force of 147.1N; when the initial test force is reached, hold for 15s and record it as the baseline indentation depth h0. Subsequently, load to the total test force and maintain for 15s, and measure the final indentation depth h1; by calculating the residual indentation depth h (the calculation method is: h = h1 - h0), the Rockwell hardness H of the mortar matrix in the concrete can be further calculated:

[0069]

[0070] Similarly, for the sample of the coarse aggregate phase, a rock sample of the same material as the coarse aggregate is selected and measured according to the methods of Step 1 and Step 2 above.

[0071] Similarly, in the test method for the Rockwell hardness of fibers, considering that the fiber diameter is relatively small (generally 0.2mm), the Rockwell hardness of all fibers is measured from the fiber parent material test blocks, and the fiber parent material test blocks refer to: test blocks of the same material as the fiber phase, which can be obtained by cutting fiber raw materials.

[0072] The method for obtaining the equivalent length of each phase in the fiber-reinforced cement-based material includes the steps:

[0073] Each component phase in the fiber-reinforced cement-based material is respectively equivalent to a cube, and the volume of the cube is determined by the volume ratio of each phase; take the cube root of the volume of the cube to obtain the side length of the cube, which is used as the equivalent length of the phase;

[0074] Among them, the calculation method of the equivalent length of the fiber phase is as follows: Multiply the volume ratio of the equivalent cube of the fiber phase by the correction coefficient k, and then take the cube root of the volume corrected by the correction coefficient k to obtain the equivalent length of the fiber phase. This is because in fiber-reinforced cement-based materials, different materials, shapes, and structures of fibers will have different degrees of influence on the hardness and anti-penetration performance of fiber-reinforced cement-based materials, and it is difficult to measure these influences solely by volume ratio. Specifically, when the fiber is a straight copper-plated steel fiber, k is taken as 1.0; when the fiber is a hooked copper-plated steel fiber, k is taken as 1.2; when the fiber is an organic fiber, k is taken as 0.9.

[0075] For the calculation of the effective hardness of fiber-reinforced cement-based materials, the effective hardness of fiber-reinforced cement-based materials is denoted as H effective, and the weighted calculation method is as follows:

[0076]

[0077] Among them,

[0078] is the equivalent length of the coarse aggregate in the fiber-reinforced cement-based material; is the equivalent length of the mortar matrix in the fiber-reinforced cement-based material;

[0079] is the equivalent length of the fiber in the fiber-reinforced cement-based material. The value of k is selected according to the type of fiber. When the fiber is a straight copper-plated steel fiber, k is taken as 1.0; when the fiber is a hooked copper-plated steel fiber, k is taken as 1.2; when the fiber is an organic fiber, k is taken as 0.9;

[0080] H 粗骨料 is the Rockwell hardness value of the coarse aggregate in the fiber-reinforced cement-based material;

[0081] H 基体 is the Rockwell hardness value of the mortar matrix in the fiber-reinforced cement-based material;

[0082] H 纤维 is the Rockwell hardness value of the fiber in the fiber-reinforced cement-based material.

[0083] As Figure 2 shown, this method re-concentrates the dispersed constituent phases of the fiber-reinforced cement-based material into cubes respectively, and arranges the cubes in sequence on the bullet trajectory 1. When the bullet 2 contacts the mortar matrix phase 3 at the front end, the coarse aggregate phase 4 and the fiber phase 5 arranged at the back are simultaneously subjected to the force applied by the bullet 2, and multiple constituent phases resist the impact of the bullet 2 as a whole. In terms of the calculation of the effective hardness, the effective hardness is obtained by weighting the effective hardness of each constituent phase.

[0084] The test method for the anti-penetration performance of fiber-reinforced cement-based materials includes the steps:

[0085] (1) Prepare a fiber-reinforced cement-based material target with dimensions of 300×170×150 mm 3 (where 150 mm is the thickness along the ballistic direction); Prepare the test projectile. The projectile is a conical warhead with a diameter of 8 mm, made of ASSAB XW-42 high-strength alloy steel. The yield strength of the projectile material is 2150 - 2200 MPa, the peak strength is 2950 - 3100 MPa, and the Rockwell hardness is 60 - 62 HRC.

[0086] (2) Set up a high-speed projectile penetration device. Use a ballistic smoothbore gun to launch the projectile. The launch direction is parallel to the thickness direction of the target along the ballistic path, and make the penetration pit located at the center of the target plane; During the process, use a laser velocity measurement system to measure the projectile velocity before and after launch, and use a high-speed camera to monitor whether the ballistic direction is perpendicular to the target to exclude non-typical test results caused by launch angle deviation.

[0087] (3) Conduct an anti-penetration test. Measure the damage degree of the cement-based material target under the action of a high-speed projectile with a set projectile velocity through the penetration depth (i.e., the distance from the projectile penetrating the target to the deepest point) and the crater diameter (the diameter of the equivalent circle with the same area as the crater);

[0088] And calculate the normalized penetration depth Y through the penetration depth 侵彻深度 , and the calculation method is: Normalized penetration depth = Penetration depth / Impact velocity, where the impact velocity is obtained by measuring the projectile velocity after launch using a laser velocity measurement system.

[0089] Example 2

[0090] Use 5 different mix ratios of neat cement paste (numbered CP-1 to 5) to obtain the values of effective hardness and anti-penetration performance according to the method of Example 1, and test their compressive strength; Among them, since there is no coarse aggregate phase and fiber phase, the effective lengths of both the coarse aggregate phase and the fiber phase are 0.

[0091] Use 7 different mix ratios of cement mortar (numbered CM-1 to 7) to obtain the values of effective hardness and anti-penetration performance according to the method of Example 1, and test their compressive strength; Among them, since there is no coarse aggregate phase and fiber phase, the effective lengths of both the coarse aggregate phase and the fiber phase are 0.

[0092] Use 7 different mix ratios of concrete materials (numbered CC-1 to 7) to obtain the values of effective hardness and anti-penetration performance according to the method of Example 1, and test their compressive strength; Among them, the components of the concrete include cement mortar and coarse aggregate, without fibers, so the effective length of the fiber phase is 0.

[0093] Two types of engineered cementitious composites with different mix ratios (designated as ECC-1 to 7) were used to obtain the values of effective hardness and anti-penetration performance according to the method of Example 1, and their compressive strengths were tested. Among them, the components of the engineered cementitious composites include water, silica fume, fly ash, fibers, water reducer, and river sand. Among them, the river sand is fine aggregate and is part of the composition of the cement mortar. Coarse aggregate is not included, so the effective length of the coarse aggregate phase is 0.

[0094] Four types of ultra-high performance concretes with different mix ratios (designated as UHPC-1 to 4) were used to obtain the values of effective hardness and anti-penetration performance according to the method of Example 1, and their compressive strengths were tested. Among them, the components of the ultra-high performance concrete include: cement mortar matrix, coarse aggregate, and fibers.

[0095] Granite as the coarse aggregate was obtained, and the values of effective hardness and anti-penetration performance were obtained according to the method of Example 1, and its compressive strength was tested. Among them, the granite does not include cement mortar and fibers, so the effective lengths of the matrix phase and the fiber phase are 0. An example of the calculation of effective hardness is shown in Table 1.

[0096] Table 1

[0097]

[0098] Substituting the data in Table 1 into the weighted calculation method in Example 1, the calculation result of the effective hardness is:

[0099]

[0100] Through actual tests, the compressive strengths, normalized penetration depths, and crater diameters of each material obtained were summarized with the effective hardness obtained in Table 1, as shown in Table 2.

[0101] Table 2

[0102]

[0103]

[0104] According to the data in Table 1 for data statistical processing, a relationship diagram of effective hardness and normalized penetration depth as shown in Figure 3 was obtained, and a relationship diagram of effective hardness and crater diameter as shown in Figure 4 was obtained. It can be seen that there is an obvious linear relationship between the effective hardness and the anti-penetration performance, and it can be evaluated according to the effective hardness.

[0105] After sorting out: The linear relationship between the effective hardness and the normalized penetration depth is as shown by the dotted line in Figure 3 The evaluation method of the normalized penetration depth Y 侵彻深度 is:

[0106] Y 侵彻深度 = -0.411H 有效 + 45.004; R 2 = 0.91;

[0107] The linear relationship between the effective hardness and the crater diameter is as shown by the dashed line in Figure 4 The evaluation method of the crater diameter Y 开坑直径 is as follows:

[0108] Y 开坑直径 = -0.513H 有效 + 92.016; R 2 = 0.80;

[0109] where Y 侵彻深度 is the normalized penetration depth; the normalized penetration depth = penetration depth / impact velocity, where the impact velocity is obtained by measuring the projectile velocity with a laser velocimeter after launch.

[0110] Y 开坑直径 is the diameter of the equivalent circle with the same area as the crater.

[0111] As can be seen from Table 2, the compressive strength of the cement and materials participating in the fitting is 30 - 240 MPa.

[0112] Example 3

[0113] This example corresponds to step S6. The numerical value of the effective hardness of the fiber - reinforced cement - based material with unknown anti - penetration performance is obtained according to the method of Example 1; for the effective hardness of each material obtained, substitute the effective hardness into the calculation methods of the penetration depth and the crater diameter in Example 2 to obtain the evaluated penetration depth Y 侵彻深度 and the crater diameter Y 开坑直径 .

[0114] According to the anti - penetration performance of the specimen in this example actually measured by the method of Example 1, the evaluated penetration depth Y 侵彻深度 and the crater diameter Y 开坑直径 are in good agreement with the actually measured data, indicating that the anti - penetration performance evaluation method obtained in this example can be applied to fiber - reinforced cement - based composites with unknown performance.

[0115] Comparative Example

[0116] This comparative example provides another calculation method for the effective hardness. The difference from Example 1 is that the method for obtaining the effective length is:

[0117] As Figure 5As shown, each constituent phase in the fiber-reinforced cementitious material is equivalently regarded as a cuboid with the same cross-sectional area but different thicknesses. The volume of the cuboid is determined by the volume ratio of each phase, including the mortar matrix phase 3, the coarse aggregate phase 4, and the fiber phase 5 arranged in sequence, and the cuboids are arranged in sequence on the bullet trajectory 1. The multiple constituent phases act as a whole to resist the impact of the bullet 2; the volume of each cuboid is divided by the same cross-sectional area, and the obtained thickness is used as the equivalent length of the phase, that is, the equivalent length is in a direct proportional relationship with the volume of each phase, rather than the cube root relationship; the obtained effective hardness is denoted as H 对比 .

[0118] Data processing shows that: H 对比 There is no obvious linear relationship between the numerical relationship of the anti-penetration performance, and the anti-penetration performance of the fiber-reinforced cementitious material cannot be evaluated by using the effective length acquisition method in the comparative example.

[0119] The present invention uses the effective hardness as a new index to measure the anti-penetration performance of the fiber-reinforced cementitious material. The applications in Examples 2 to 3 show that as the effective hardness increases, the anti-penetration performance of the material is correspondingly enhanced. It shows that the evaluation method of the anti-penetration performance of the fiber-reinforced cementitious material provided by the present invention can provide important theoretical support and practical guidance for the further research and development of cementitious materials.

[0120] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for evaluating the anti-penetration performance of fiber-reinforced cement-based materials, characterized in that: The following steps are involved: S1. The fiber-reinforced cement-based material is taken as a three-phase material consisting of a mortar matrix phase, a coarse aggregate phase and a fiber phase, and each component of the fiber-reinforced cement-based material is divided into three component phases; S2. Obtain samples of all constituent phases and test the Rockwell hardness of each phase respectively; S3. Calculate the equivalent length of each phase according to the volume ratio of each phase in the fiber-reinforced cement-based material; obtain the equivalent length of the mortar matrix through the volume ratio of the mortar matrix phase, the coarse aggregate phase and the fiber phase; obtain the equivalent length of the coarse aggregate; obtain the equivalent length of the fiber; the equivalent length of each phase is obtained by the cube root of the volume fraction of each phase; the equivalent length of the fiber phase is corrected according to the fiber type; the calculation method of the equivalent length of the fiber phase is: multiply the volume ratio of the equivalent cube of the fiber phase by the correction coefficient k, and then take the cube root of the volume corrected by the correction coefficient k to obtain the equivalent length of the fiber phase; S4. According to the Rockwell hardness of each phase obtained in S2 and the equivalent length of each phase obtained in S3, the effective hardness of the fiber reinforced cement-based material is obtained by weighting. In the weighted calculation method, the weight of each phase is equal to the ratio of the equivalent length of the phase to the sum of the equivalent lengths of all phases; S5. Detect the anti-penetration performance of fiber-reinforced cement-based materials of different components, and obtain the effective hardness corresponding to the fiber-reinforced cement-based materials according to S1 to S4, and establish a correlation between the effective hardness and the anti-penetration performance; The anti-penetration performance tested includes: normalized penetration depth and pit diameter; the correlation is a linear relationship; S6. According to S1 to S4, the effective hardness of the fiber-reinforced cement-based material with unknown anti-penetration performance is calculated, and matched with the correlation obtained in S5 to evaluate the anti-penetration performance of the fiber-reinforced cement-based material with unknown anti-penetration performance; Normalized penetration depth Y 侵彻深度 The evaluation method is: AND 侵彻深度 -0.41H 有效 +45.004; Pit diameter Y 开坑直径 The evaluation method is: Y 开坑直径 =-0.513H 有效 +92.016; Among them, H 有效 is the effective hardness of cement-based materials, calculated as: Among them, H 粗骨料 is the Rockwell hardness value of coarse aggregate in fiber-reinforced cement-based materials; H 基体 It is the Rockwell hardness value of the mortar matrix in the fiber-reinforced cement-based material; H 纤维 is the Rockwell hardness value of the fiber in the fiber-reinforced cement-based material; V 粗骨料 +V 基体 +V 纤维 =100%%; Among them, V 粗骨料 is the volume proportion of coarse aggregate phase in fiber-reinforced cement-based materials; V 基体 is the volume proportion of the mortar matrix phase in the fiber-reinforced cement-based material; V 纤维 is the volume proportion of the fiber phase in the fiber-reinforced cement-based material; The k value is selected according to the fiber type.

2. The method for evaluating the anti-penetration performance of fiber-reinforced cement-based materials according to claim 1, characterized in that: The mortar matrix phase includes: cement, silica fume and fly ash; The coarse aggregate phase includes: rock aggregate with a particle size of 5-16 mm; The fiber phase is one or more of straight copper-plated steel fiber, hook-shaped copper-plated steel fiber and organic fiber.

3. The method for evaluating the anti-penetration performance of the fiber-reinforced cement-based material according to claim 1, The method is characterized in that, in S2, a sample of the fiber-reinforced cement-based material is obtained, and the Rockwell hardness of the surface of the sample is tested; Obtain a coarse aggregate sample from a fiber-reinforced cement-based material and test the Rockwell hardness of the surface of the coarse aggregate sample; Obtain fiber samples from fiber-reinforced cement-based materials and test the Rockwell hardness of the fiber samples.

4. The method for evaluating the anti-penetration performance of fiber-reinforced cement-based materials according to claim 1, characterized in that: When the fiber is straight copper-plated steel fiber, k is 1.0; when the fiber is hook-shaped copper-plated steel fiber, k is 1.2; when the fiber is organic fiber, k is 0.9.

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