Concrete multi-scale structure regulation and control and abrasion resistance optimization method
Through X-ray tomography and three-dimensional reconstruction technology, combined with a multi-scale enhancement system of cellulose nanofibers and steel fibers, the pore structure of UHPC is optimized, which solves the problem of insufficient impact wear performance of UHPC in high-speed water flow environments and achieves significant improvement in impact wear performance.
Patent Information
- Application Number
- CN202510589882.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-08
- Publication Date
- 2025-08-08
AI Technical Summary
The optimization of impact wear performance of existing ultra-high performance concrete (UHPC) in high-speed sand-bearing water flow environments is insufficient, especially the interface regulation technology of nano-reinforced phases and the theory of multi-scale fiber hybrid reinforcement need to be broken through, and the impact on the structure of C-S-H gels is less studied, resulting in the lack of breakthrough in its application technical barriers in extreme environments.
X-ray tomography technology and three-dimensional reconstruction method were used to observe the pore size characteristics of concrete. A multi-scale reinforcement system was formed by incorporating cellulose nanofibers (CNFs) and steel fibers, and the pore structure was optimized. The impact-resistant grinding performance was tested using a high-speed Gaza jet grinding instrument to determine the optimal amount of CNFs added.
The pore structure of concrete is significantly optimized and the impact wear performance is improved. In particular, the impact wear effect of the mixed-mixed CNFs and steel fiber system is the most significant at a 30° punch-mixing angle. The impact wear depth and mass loss are significantly lower than that of steel fibers alone, achieving the synergistic effect of the multi-scale reinforcement system.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of concrete preparation, and in particular to a method for controlling the multi-scale structure of concrete and optimizing its anti-abrasion performance. Background Art
[0002] Cement-based materials can achieve ultra-high mechanical properties by densifying their microstructure through the addition of fine particles and fine aggregates, such as silica fume and fly ash, leveraging the closest packing effect and the pozzolanic effect. Furthermore, the incorporation of steel fibers and other fiber types creates a three-dimensional network within the concrete, enhancing the toughness of cement-based materials. Recent progress has been made in the design, preparation, and application of ultra-high-performance concrete (UHPC), but its application in environments with high-velocity, sediment-laden water flows remains relatively limited. Furthermore, research on the mechanisms for optimizing the abrasion resistance of UHPC systems remains limited, particularly in the interface control of nano-reinforced phases and the theory of multiscale fiber hybrid reinforcement. The evolution of its macro-meso-micro multiscale structure and its degradation mechanisms under multi-element erosion remain unclear, and there are still technical gaps in material-structure collaborative design methods for extreme environments. Therefore, systematic research on UHPC material performance optimization theory, environmental adaptability design methods, and engineering preparation technologies is urgently needed to overcome the technical barriers to its application in complex environmental conditions.
[0003] Calcium silicate hydrate (CSH) gel is a key component that determines the mechanical properties and durability of cement-based materials. CSH gel is a gel material characterized by a "sandwich" structure formed by the polymerization of silicate ions to form long chains of silicon-oxygen tetrahedra. These tetrahedra coordinate with calcium ions within the layers, forming a gel-like structure with interlaminar water and calcium ions. Studies have shown that changes in the Ca / Si ratio in CSH gels significantly influence the arrangement of calcium ions within and between the layers, leading to changes in structural order. Furthermore, the incorporation of cellulose nanofibers (CNFs) into CSH microstructures can significantly improve the mechanical properties and durability of UHPC by optimizing the gel's lamellar structure and interfacial bonding properties. However, few studies have examined the effects of CNFs on CSH structure. Therefore, it is crucial to further understand the underlying mechanisms of microstructural evolution in UHPC containing CNFs and to clarify the relationships between mechanical strength, hydration, phase composition, and durability, particularly impact and abrasion resistance. Summary of the Invention
[0004] In view of this, the present invention proposes a method for regulating the multi-scale structure of concrete and optimizing its anti-abrasion performance to solve the problems existing in the above-mentioned prior art.
[0005] To achieve the above objectives, the present invention proposes a method for controlling the multi-scale structure of concrete and optimizing its anti-abrasion performance, which is characterized by comprising:
[0006] Using X-ray tomography technology to obtain a two-dimensional slice image of the concrete sample, and observing the internal pore characteristics of the concrete sample through the two-dimensional slice image;
[0007] Performing three-dimensional reconstruction on the concrete sample, detecting pores and calculating layered porosity;
[0008] Mercury intrusion porosimetry and nitrogen adsorption testing were used to analyze the pore distribution and porosity of concrete samples.
[0009] Adding cellulose nanofibers into concrete and optimizing the pore structure of the concrete by adjusting the amount of the cellulose nanofibers CNFs added;
[0010] The concrete mixed with the cellulose nanofibers CNFs is subjected to an anti-abrasion performance test, including an abrasion depth and mass loss test, and the optimal addition amount of the cellulose nanofibers CNFs is determined according to the test results.
[0011] Furthermore, the addition range of the cellulose nanofibers CNFs is 0.05 wt. % to 0.15 wt. %.
[0012] Furthermore, the abrasion resistance test uses a high-speed sand-added jet abrasion instrument to evaluate the abrasion resistance of the concrete added with the cellulose nanofiber by setting different abrasion angles, abrasion speeds and sand contents.
[0013] Furthermore, the setting range of the grinding angle is 30° to 90°, the setting range of the grinding speed is 20m / s to 40m / s, and the setting range of the sand content is 30kg / m 3 Up to 100kg / m 3 .
[0014] Furthermore, the concrete also includes steel fibers and PVA fibers, and a multi-scale reinforcement system is formed by the steel fibers and PVA fibers and the cellulose nanofibers.
[0015] Furthermore, the volume content of the steel fiber is 2 vol.%, and the volume content of the PVA fiber is 2 vol.%.
[0016] Furthermore, the water-cement ratio of the concrete is 0.17, and the cement dosage is 720 kg / m 3 , silica fume dosage is 144kg / m 3 , the sand dosage is 864kg / m 3 , the dosage of water reducer is 1.0wt.%.
[0017] Furthermore, the concrete samples were pretreated before the abrasion resistance test, including drying until the surface was dry and weighing to record the initial mass, and drying again to a constant weight after the test and calculating the mass loss.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] The present invention significantly optimizes the pore structure of concrete by incorporating carbon nanofibers (CNFs) into concrete. Experimental results show that with the addition of CNFs, the number of macropores with a pore size greater than 0.1 mm in concrete is significantly reduced, the porosity is reduced, and the pore structure becomes denser, laying the foundation for improving the mechanical properties of concrete. In addition, the present invention uses a high-speed sand-added jet abrasion instrument to test the abrasion resistance of concrete incorporated with CNFs. The test results show that under different abrasion angles, abrasion speeds and sand contents, concrete incorporated with CNFs exhibits excellent abrasion resistance. In particular, at an abrasion angle of 30°, the anti-abrasion effect of CNFs is most significant, and the abrasion depth is reduced by about 20.92% compared with concrete without CNFs. Under the impact and abrasion conditions of 30° and 90°, the mass loss of the CNFs and steel fiber mixed system was significantly lower than that of the single steel fiber group, fully demonstrating the synergistic effect of the multi-scale reinforcement system; finally, by rationally controlling the addition amount of CNFs, the present invention can prepare ultra-high performance concrete with different pore structures and impact and abrasion resistance according to different needs to meet different building structure requirements. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Various other advantages and benefits will become apparent to those skilled in the art by reading the detailed description of the preferred embodiment below. The accompanying drawings are only for the purpose of illustrating the preferred embodiment and are not to be considered as limiting the present invention. In the accompanying drawings:
[0021] Figure 1 : slice images of concrete samples at different positions in an embodiment of the present invention, wherein group (a) is a slice image of the sample numbered REF, group (b) is a slice image of the sample numbered C05, group (c) is a slice image of the sample numbered C10, group (d) is a slice image of the sample numbered C15, group (e) is a slice image of the sample numbered CSF, and group (f) is a slice image of the sample numbered CPVA;
[0022] Figure 2 2D pore distribution of different samples in the embodiment of the present invention;
[0023] Figure 3 The hierarchical porosity curves of different samples in the examples of the present invention, where (a) is the REF group, (b) is the C05 group, (c) is the C10 group, (d) is the C15 group, (e) is the CSF group, and (f) is the CPVA group;
[0024] Figure 4 Pore characterization of mixtures of different samples doped with different CNFs, where (a) and (b) are the pore distribution results after mercury intrusion porosimetry (MIP) testing, and (c) and (d) are the pore distribution results after nitrogen adsorption (BET) testing;
[0025] Figure 5 The abrasion depth diagram of UHPC caused by sand-laden water flow at different angles;
[0026] Figure 6 The mass loss diagram of UHPC caused by sand-laden water flow at different angles;
[0027] Figure 7 The figure is an overall flow chart of the method of the present invention. DETAILED DESCRIPTION
[0028] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, unless there is a conflict, the embodiments of the present disclosure and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0029] This embodiment proposes a method for controlling the multi-scale structure of concrete and optimizing its anti-abrasion performance, including:
[0030] Using X-ray tomography technology to obtain a two-dimensional slice image of the concrete sample, and observing the internal pore characteristics of the concrete sample through the two-dimensional slice image;
[0031] Perform 3D reconstruction of concrete samples, detect pores and calculate layered porosity;
[0032] Mercury intrusion porosimetry and nitrogen adsorption testing were used to analyze the pore distribution and porosity of concrete samples.
[0033] Adding cellulose nanofibers into concrete and optimizing the pore structure of concrete by adjusting the amount of cellulose nanofibers CNFs added;
[0034] The abrasion resistance of concrete incorporated with cellulose nanofibers CNFs was tested, including abrasion depth and mass loss tests. Finally, the optimal amount of cellulose nanofibers CNFs added was determined based on the test results.
[0035] The detailed implementation process of this embodiment is as follows:
[0036] First, X-ray computed tomography (X-CT) technology is used to obtain two-dimensional slice images of concrete samples, so that the characteristics of the internal pore size of the concrete samples can be directly observed. By comparing the slice data of different samples, it is possible to understand how nanomaterials improve the internal pore structure of mortar. The sample slice image after X-CT processing is as follows: Figure 1 As shown. From the images of the REF group, it can be clearly observed that there are a large number of large pores inside the sample. At the same time, there are many small pores evenly distributed in the entire field of view. From the slice images of the C05, C10 and C15 groups, it can be seen that after adding CNFs, the number of large and small pores is significantly reduced. Obvious large pores appear in the field of view of the slice image of the mixed sample of CNFs and PVA fibers. From the results of 2D pore distribution ( Figure 2 ), with the addition of CNFs, the proportion of pores with a diameter greater than 0.1 mm in the sample becomes smaller. This indicates that the presence of CNFs optimizes the pore structure of the sample. From the side, it shows that the addition of CNFs promotes the production of more hydration products and fills the pore structure, making it denser. However, the proportion of pores with a diameter less than 0.1 mm increases, indicating that the addition of CNFS refines the pore structure. After adding steel fibers and PVA fibers to the sample, the pore size in the field of view becomes significantly larger, but the number of pores decreases compared with the REF group. This is because PVA fibers with hydroxyl functional groups on the surface form intermolecular hydrogen bonds with the cement matrix and are tightly bound to the cement matrix. The increase in the viscosity of the cement slurry causes many small pores to aggregate together to form large pores. The large pores in the mixed samples of CNFs and steel fibers may be caused by the mixing of air into the cement slurry during the mixing process.
[0037] In order to avoid the randomness of the finite layer error of the two-dimensional slice, the pores detected after the three-dimensional reconstruction of the sample are divided into two categories: large pores ([0.1,1]mm 3 ) and small pores ([0.01,0.1]mm 3 ). Figure 3The stratified porosity curve was statistically analyzed. The average stratified porosity of the REF group was higher and fluctuated significantly. The addition of CNFs reduced the number of pores and lowered the porosity. When the addition amount of CNFs was 0.05wt.%, the average stratified porosity decreased, with smaller fluctuations at the bottom of the curve and larger fluctuations at the top. The reason for this phenomenon is that the bubbles generated during the vibration of the concrete move upward, resulting in larger fluctuations in the pores at the top. As the addition amount of CNFs increased to 0.1wt.% and 0.15wt.%, the average stratified porosity was smaller than that of the REF group, but increased compared to the C05 group. In particular, when the addition amount was 0.15wt.%, the porosity curve increased again, showing a "more at the bottom, less at the top" distribution. This is because the fluidity of the mixture is poor and the pores cannot be effectively eliminated by vibration. The same reason also explains the change pattern of the stratified porosity of the samples incorporating PVA fibers.
[0038] The porosity of the 3D model was characterized by calculating the percentage of pore volume to total volume within the 3D model. The data are shown in Table 1. The 3D porosity of groups C05, C10, and C15 was 2.64%, 3.24%, and 3.51%, respectively. Compared to the porosity of 3.83% in the REF group, the porosity of the samples incorporating CNFs decreased. This indicates that the incorporation of CNFs promoted hydration reactions and produced more CSH. The incorporation of steel fibers reduced the 3D porosity of the samples, as the steel fibers dispersed the cement paste more evenly and optimized the pore structure. The nanometer size and high specific surface area of CNFs also contributed to the reduction in 3D porosity. The number and average volume of pores of varying sizes within the 3D model were statistically analyzed and are shown in Table 3-1. The average volume of the samples in each group remained largely unchanged, but the number of open pores decreased in the samples incorporating CNFs. Open pores create stress concentration points within concrete. When subjected to external forces, cracks easily form and expand around these pores, affecting mechanical properties. With the increase of CNFs, the average volume of open pores decreases, which also accounts for the improved mechanical properties. Furthermore, excessive numbers and volumes of open pores can easily cause concrete to shrink, deform, and even crack, affecting its volume stability. Although the addition of CNFs does not improve the distribution of closed pores, closed pores within a reasonable range can alleviate stress concentration to a certain extent. Therefore, the addition of CNFs has a positive effect on the mechanical properties of UHPC.
[0039] Table 1
[0040]
[0041] Pore structure distribution
[0042] The pore distribution of UHPC was tested by mercury intrusion porosimetry (MIP). Figure 4As shown in (a) and (b). Compared with ordinary concrete, the cumulative porosity of UHPC is very low, which is because the optimized mix ratio and low water-binder ratio improve the density of the microstructure. When 0.1wt.% CNFs are added, the cumulative pore volume of the sample is reduced by 36.2% compared with the REF group. When CNFs are added alone, the total porosity of the sample decreases slightly. The reduction in porosity is caused by the filling effect of CNFs. This phenomenon shows that the addition of CNFs effectively optimizes the pore structure. The changes in the microstructure can be intuitively observed from the changes in the pore size distribution, and this evolution of the microstructure explains the enhancement of the mechanical properties of UHPC. Therefore, the reasonable addition of CNFs can significantly improve the mechanical properties of UHPC materials.
[0043] In order to further understand the effect of CNFs on the pore structure of UHPC, and to fully understand the number and distribution of gel nanopores (10nm), mesopores (10-50nm) and capillary pores (50-100nm), nitrogen adsorption (BET) tests were performed on the samples. The results are as follows: Figure 4 (c) and (d) show the average pore sizes of the REF group and the CNFs-only group were 9.33 nm, 10.48 nm, 8.02 nm, and 11.75 nm, respectively. Nitrogen adsorption tests showed that the porosity in the 10–50 nm range decreased significantly with the addition of CNFs. The results further demonstrated that the UHPC internal microstructure became denser after the addition of CNFs. After the steel fiber and CNFs were mixed, the cumulative pore volume was minimized in the pore size range of 1–100 nm. This trend is consistent with the X-CT results mentioned above, indicating that the synergistic effect of CNFs and steel fibers improves the pore structure at the microscopic level. Furthermore, CNFs act as internal curing agents, providing water for cement hydration. This internal curing effect is associated with the formation of pores with a diameter of 50 nm. Most importantly, the reduction of shrinkage cracks in ultra-high-performance cement-based materials is achieved through the "bridging" effect of CNFs, which tightens the microstructure and inhibits pore expansion.
[0044] It is noteworthy that the addition of CNFs reduced the volume of mesopores and capillary pores (pore diameters greater than 10 nm), while the volume of gel pores (pore diameters less than 10 nm) showed the opposite trend. The C10 group had more gel pores than the REF group, and the formation of gel pores is generally associated with the formation of CSH. Furthermore, the water-cement ratio plays a decisive role in the formation of pore structure, and increasing the water-cement ratio significantly alters the pore structure characteristics. The internal curing effect of CNFs only reduced the number of pores with larger diameters, but led to an increase in the number of small pores that were internally hydrated. This phenomenon is related to the water storage capacity of CNFs. During hydration, the water stored within CNFs is released, promoting the production of more hydration products to fill the pores. Therefore, the reduction in cumulative pore volume may also be a result of the internal curing of CNFs. Based on these phenomena, the internal curing effect of CNFs is related to the formation of pore structure. The effect of internal curing becomes more significant with increasing curing age. Therefore, the porosity of samples containing CNFs is lower than that of the REF group.
[0045] Concrete abrasion resistance test
[0046] The instrument used in this test is a high-speed sand-adding jet abrasion instrument, which consists of a control center and an instrument body. The control center dynamically adjusts the speed of the multi-stage centrifugal pump (0-500rpm) through variable frequency speed regulation technology, and combines the real-time feedback data of the electromagnetic flowmeter to achieve precise control of the water pressure from 0 to 15MPa (±0.1MPa). At the same time, the gear speed (0-50rpm) is controlled by the double screw conveyor and the weighing sensor to achieve a sand content of 0.1-0.8kg / m 3 Precise mixing ratio. The instrument consists of a high-pressure water system driven by a multi-stage centrifugal pump, a 50L sand storage tank with a vibrating anti-clogging device, a plastic nozzle, and an angular sample holder. The working principle is that the water is pressurized to a set value by the water pump, mixed with the sand in the sand storage tank, and then sprayed onto the sample surface through the nozzle according to the set parameters.
[0047] The specific process is as follows: First, a multi-stage centrifugal pump pressurizes water to 0-15MPa and delivers it to the contraction section, where the water pressure is dynamically adjusted using variable frequency speed regulation technology. Subsequently, the machine-made sand (particle size 0.1-0.16mm) in the sand storage tank is pneumatically vibrated to break the arch bridge effect and quantitatively delivered to the mixing chamber via a double-screw conveyor. The negative pressure effect of the high-speed water flow forms a solid-liquid two-phase flow, and the sand content in the water flow can be controlled to 100kg / m 3 The mixed sand-laden water flow passes through a plastic nozzle (d = 2 mm) and impacts the surface of the sample fixed on the metal stage. The spray angle can be adjusted from 0 to 90 degrees.
[0048] Test methods
[0049] Different impact angles (α), impact velocities (v), and sediment concentrations (C) were set to comprehensively evaluate the impact resistance of ultra-high performance concrete (UHPC) subjected to sediment-laden flow. The control variable method was used, and the operating conditions are shown in Table 2.
[0050] Table 2
[0051]
[0052] The abrasive used in the experiment was machine-made sand with a particle size of 0.1 to 0.16 mm, and the sample was a concrete specimen with a size of 50 × 50 × 10 mm. In order to compare the anti-abrasion effect of nanofibers, a group of samples with 2 vol% steel fiber added alone was used as a control group, numbered SF. Its mix ratio and mechanical properties are shown in Tables 3 and 4. The test process is as follows: ① Sample pretreatment: After completing the preparation and curing of the concrete sample, place it in a 60°C oven to dry for 2 hours to ensure that the surface is dry; ② Weighing before the test: The dried concrete sample is accurately weighed and the initial mass is recorded; ③ Post-test processing: After the test, the sample is dried again to a constant weight (the mass error is controlled within ±0.001g), and the mass loss during the abrasion process is calculated based on the mass data before and after.
[0053] Table 3
[0054]
[0055] Table 4
[0056]
[0057] Abrasion resistance of concrete under different working conditions
[0058] The influence of grinding angle:
[0059] The maximum depth of the sample at different grinding angles is as follows Figure 5 As shown in the figure. Data analysis shows that the impact of the grinding angle on the sample shows the following pattern: in the range of 30-45°, the grinding depth gradually decreases with the increase of the angle, and in the range of 45-90°, the grinding depth increases with the increase of the angle. When the grinding angle is 30° and the sand content is 100kg / m 3At a speed of 40 m / s, samples incorporating cellulose nanofibers (CNFs) exhibited excellent abrasion resistance. In particular, compared to steel fibers, the abrasion depth decreased from 2.82 mm to 2.23 mm, a decrease of approximately 20.92%. However, as the abrasion angle increased, the abrasion resistance of CNFs declined compared to that of samples incorporating steel fibers. This may be because as the abrasion angle increased, especially at a 90° angle, the kinetic energy conversion loss of the sediment-laden water flow decreased, weakening the nanoscale toughening mechanism. The abrasion resistance advantages of steel fibers are primarily manifested in two aspects: First, steel fibers construct a local three-dimensional network structure within the concrete. Under impact loads, this structure, through the spatial support system formed by the interwoven fibers, effectively resists the transfer of impact energy and reduces the degree of damage to the matrix material. Second, steel fibers possess high tensile strength and, during impact, dissipate impact energy through tensile deformation and fracture, reducing the transfer of energy to the concrete matrix. The synergistic effect of the two ultimately reduced the abrasion depth of steel fiber reinforced concrete under 90° impact by approximately 13.6% and 6.7% compared to the REF group and the sample with only nanofibers, respectively. It is worth noting that when CNFs are mixed with steel fibers, the two significantly improve the abrasion resistance of UHPC through a synergistic effect. Among them, CNFs effectively inhibit the propagation of microcracks through a nanoscale toughening mechanism, while steel fibers constrain macro cracking through a three-dimensional network structure. Under 30° abrasion conditions, the toughening effect of nanofibers is particularly prominent, which improves the abrasion resistance of UHPC by approximately 29.33% compared to the single-steel fiber group. This shows that in small-angle impact scenarios, nanofibers and steel fibers form a multi-scale reinforcement system, which can achieve gradient dissipation of impact energy, thereby significantly delaying the abrasion damage of UHPC.
[0060] In order to evaluate the improvement effect of nanofiber on the impact and wear resistance of UHPC, this example uses mass loss as a quantitative indicator to conduct comparative analysis from the perspective of material quality damage. Figure 6 As shown. By analyzing the effect of different CNF dosages on the mass loss of UHPC after abrasion and grinding, it can be seen that under the 30% abrasion and grinding condition, the mass loss of UHPC is significantly correlated with the nanofiber dosage. Specifically, when the CNF dosage is 0.05wt.% and 0.15wt.%, the mass loss of the sample is 0.3132g and 0.3432g, respectively, which is significantly lower than that of the single steel fiber group (0.3846g), and the mass loss decreases by about 18.56%. This is consistent with the law of the abrasion depth test results. The multi-scale synergistic toughening mechanism shows significant advantages in the optimization of UHPC abrasion resistance: under 30-90% abrasion and grinding conditions, the mass loss of the CNFs and steel fiber mixed system is significantly lower than that of the single steel fiber group. This phenomenon fully confirms the synergistic effect of the "macro-micro" multi-scale reinforcement system.
[0061] The overall flow chart of the method of the present invention is as follows Figure 7 As shown, in summary, the present invention achieves the optimization of microstructure and the improvement of macroscopic performance by regulating the multi-scale structure of concrete, providing strong technical support for the high performance and durability improvement of concrete materials. It can be widely used in water conservancy and hydropower engineering, marine engineering, bridge engineering and other fields with high requirements on the impact and abrasion resistance of concrete, and has significant economic benefits.
[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.
Claims
1. A method for controlling the multi-scale structure of concrete and optimizing its anti-abrasion performance, characterized in that: include: Using X-ray tomography technology to obtain a two-dimensional slice image of the concrete sample, and observing the internal pore characteristics of the concrete sample through the two-dimensional slice image; Performing three-dimensional reconstruction on the concrete sample, detecting pores and calculating layered porosity; Mercury intrusion porosimetry and nitrogen adsorption testing were used to analyze the pore distribution and porosity of concrete samples. Adding cellulose nanofibers into concrete and optimizing the pore structure of the concrete by adjusting the amount of the cellulose nanofibers CNFs added; The concrete mixed with the cellulose nanofibers CNFs is subjected to an anti-abrasion performance test, including an abrasion depth and mass loss test, and the optimal addition amount of the cellulose nanofibers CNFs is determined according to the test results.
2. The method for controlling the multi-scale structure of concrete and optimizing its anti-abrasion performance according to claim 1, characterized in that: The addition range of the cellulose nanofibers CNFs is 0.05 wt. % to 0.15 wt. %.
3. The method for controlling the multi-scale structure of concrete and optimizing its anti-abrasion performance according to claim 1, wherein: The abrasion resistance test uses a high-speed sand-added jet abrasion instrument to evaluate the abrasion resistance of the concrete to which the cellulose nanofibers are added by setting different abrasion angles, abrasion speeds and sand contents.
4. The method for controlling the multi-scale structure of concrete and optimizing its anti-abrasion performance according to claim 3, characterized in that: The setting range of the grinding angle is 30° to 90°, the setting range of the grinding speed is 20m / s to 40m / s, and the setting range of the sand content is 30kg / m 3 Up to 100kg / m 3 .
5. The method for controlling the multi-scale structure of concrete and optimizing its anti-abrasion performance according to claim 1, wherein: The concrete also includes steel fibers and PVA fibers, and a multi-scale reinforcement system is formed by the steel fibers and PVA fibers and the cellulose nanofibers.
6. The method for controlling the multi-scale structure of concrete and optimizing its anti-abrasion performance according to claim 5, characterized in that: The volume content of the steel fiber is 2 vol.%, and the volume content of the PVA fiber is 2 vol.%.
7. The method for controlling the multi-scale structure of concrete and optimizing its anti-abrasion performance according to claim 1, characterized in that: The water-cement ratio of the concrete is 0.17, and the cement dosage is 720 kg / m 3 , silica fume dosage is 144kg / m 3 , the sand dosage is 864kg / m 3 , the dosage of water reducer is 1.0wt.%.
8. The method for controlling the multi-scale structure of concrete and optimizing its anti-abrasion performance according to claim 1, wherein: The concrete samples were pretreated before the abrasion resistance test, including drying until the surface was dry and weighing to record the initial mass. After the test, the concrete samples were dried again to a constant weight and the mass loss was calculated.