High toughness cement concrete pavement material and anti-cracking construction method

Abstract

This invention relates to the field of building materials and construction technology, and discloses a high-toughness cement concrete pavement material and a crack-resistant construction method. The pavement material includes silicate cement, a multi-stage expansion system, multi-scale fibers, and porous fine aggregates with water release in a multi-gradient humidity zone. The crack-resistant construction method includes pre-preparing a carrier premix to establish a basic rheology, and adding multi-scale fibers in staggered shifts based on feedback from the operating power and energy accumulation of the main mixer. By releasing water as needed when the relative humidity of the porous fine aggregate decreases in the matrix, corresponding fast and slow reaction expansion agents are triggered, achieving shrinkage compensation throughout the material's lifespan. Simultaneously, by combining the physical unbinding effect of the aggregate with rheological timing control of the feeding, the probability of multi-scale fiber entanglement and agglomeration is reduced, avoiding mechanical wear of the fibers due to ineffective mixing, and effectively improving the overall toughness and volume stability of the pavement material.

Description

Technical Field

[0001] This invention relates to the field of building materials and construction technology, specifically to a high-toughness cement concrete pavement material and a crack-resistant construction method. Background Technology

[0002] Cement concrete is widely used in road engineering due to its high mechanical strength and durability. To improve the inherent brittleness and cracking tendency of cement concrete, existing technologies typically incorporate various micro or macro fibers into the mixture to enhance the structural toughness of the material, and add expansion agents to compensate for the volume shrinkage of the matrix. Simultaneously, some technical solutions also introduce pre-wetted porous materials as an internal curing medium to mitigate the self-shrinkage caused by the loss of internal moisture in the concrete.

[0003] While the aforementioned conventional methods have improved the road performance of concrete to some extent, they still face some technical limitations in practical engineering applications. The shrinkage process of cement concrete continues throughout different ages, and existing single expansion systems or conventional internal curing materials are difficult to match with the relative humidity changes at different development stages of the matrix, making it difficult to achieve stable shrinkage compensation throughout the entire cycle. Simultaneously, multi-scale fibers introduced to construct a multi-layered crack-resistant network are prone to entanglement due to differences in physical dimensions under conventional dry-mixing or blending processes, resulting in uneven dispersion and agglomeration in the matrix, thus limiting the effectiveness of the multi-fiber composite crack-resistant effect.

[0004] In the preparation of existing pavement materials, the addition and mixing of fibers are usually controlled by a fixed set time, lacking an objective assessment of the actual rheological state of the materials. This static control mode is difficult to accurately reflect the wetting and physical termination process of multi-scale fibers. If the mixing time is extended simply to pursue dispersion, it can easily cause mechanical wear or even breakage of the organic fiber surface. Insufficient mixing, on the other hand, cannot guarantee the macroscopic homogeneity of the system, making it difficult to maintain the stability of concrete construction quality. Therefore, this invention provides a high-toughness cement concrete pavement material and a crack-resistant construction method to address the shortcomings of the existing technology. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-toughness cement concrete pavement material and a crack-resistant construction method, which solves the problems of shrinkage cracking risk in cement concrete pavement materials at different ages, and the difficulty in fully exerting multiple crack-resistant effects due to uneven dispersion and agglomeration of multi-scale fibers in the matrix.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a high-toughness cement concrete pavement material, employing the following technical solution: A high-toughness cement concrete pavement material is made from the following components in parts by weight: 285-320 parts silicate cement; 45-60 parts slag powder; 25-40 parts fly ash; 15-18 parts silica fume; 12-24 parts calcium sulfoaluminate expansive agent; 4-7 parts fast-reacting magnesium oxide expansive agent; 7-12 parts slow-reacting magnesium oxide expansive agent; 600-660 parts natural fine aggregate; 1000-1080 parts coarse aggregate; 138-150 parts effective mixing water; 2.8-4.0 parts polycarboxylate superplasticizer; 0.3-0.5 parts air-entraining agent; 0.6-0.9 parts polypropylene microfiber; 1.4-3.0 parts short-scale macro-polyolefin fiber; 1.6-3.3 parts long-scale macro-polyolefin fiber; 25-45 parts water-releasing porous fine aggregate in high humidity areas; and 45-70 parts water-releasing porous fine aggregate in low humidity areas.

[0007] By employing the above technical solution, this invention achieves a certain degree of compensation for shrinkage at various ages within the material through the synergistic cooperation of multi-gradient humidity-releasing porous fine aggregates and a multi-stage expansion system. Specifically, calcium sulfoaluminate-based expansion agents react and generate volume expansion in the early stages of matrix hydration, primarily to alleviate plastic shrinkage. As hydration progresses, when the relative humidity of the matrix is ​​high, the high-humidity zone water-releasing porous fine aggregates begin to release internal moisture and work together with the fast-reacting magnesium oxide expansion agent to compensate for mid-term shrinkage. As the relative humidity further decreases, the low-humidity zone water-releasing porous fine aggregates release water, at which point the delayed-reacting magnesium oxide expansion agent is activated, helping to maintain the long-term volume stability of the material. Furthermore, while serving as a carrier of functional components, the multi-scale aggregates, with their physical network of multi-scale fibers spanning cracks of different scales, can, to a certain extent, inhibit the initiation and propagation of cracks.

[0008] Preferably, the 24-hour water absorption rate of the high-humidity zone water-releasing porous fine aggregate is not less than 21%, and the internal capillary pore size is distributed in the range of 50-200nm; the high-humidity zone water-releasing porous fine aggregate includes coarse and fine particles; the 24-hour water absorption rate of the low-humidity zone water-releasing porous fine aggregate is not less than 23%, and the internal capillary pore size is distributed in the range of 10-50nm.

[0009] By employing the above technical solution, this invention utilizes the difference in water binding force of capillaries with different pore sizes to regulate the water release process. Specifically, porous fine aggregates with pore sizes of 50-200 nm in the high humidity zone tend to release water when the relative humidity inside the concrete drops to 90%, while porous fine aggregates with pore sizes of 10-50 nm in the low humidity zone typically release water when the relative humidity drops to 85% or below, thus adapting the water release trajectory to the hydration development stage of the matrix.

[0010] Preferably, the pavement material satisfies the following equivalent coefficient relationship: WIC / (0.035Mb+0.447MB) is between 1.05 and 1.35; where WIC is the total free water carried by all porous fine aggregates; Mb is the total mass of silicate cement, slag powder, fly ash and silica fume in the system; and MB is the total mass of delayed reaction magnesium oxide expansion agent.

[0011] By adopting the above technical solution, this invention establishes a correlation between the total amount of internal curing water and the hydration requirements of the cementitious material and magnesium oxide expanding agent through the aforementioned equivalent coefficient range. This design aims to retain enough moisture within the matrix to sustain hydration and expansion reactions over a longer period, while reducing the risk of increased porosity and strength degradation due to excessive moisture.

[0012] Preferably, the polypropylene microfibers are 3-12 mm in length and 15-40 μm in diameter; the short-scale macroscopic polyolefin fibers are 25-35 mm in length; and the long-scale macroscopic polyolefin fibers are 45-55 mm in length, with continuous indentations or rough textures on the surface.

[0013] By employing the above technical solutions, the fiber combinations of different physical sizes construct a multi-level spatial distribution ranging from micrometers to centimeters. Polypropylene microfibers are mainly used to suppress early plastic microcracks, while short-scale macroscopic polyolefin fibers play a greater role in bridging micro-cracks and improving matrix toughness. Long-scale macroscopic polyolefin fibers, through their rough surface texture, increase mechanical interlocking with the matrix to limit the propagation of macroscopic cracks.

[0014] Preferably, the dry mixture of the road material includes a microfiber carrier mixture and a functional premix; the microfiber carrier mixture is formed by physically mixing water-treated fine-grained high-humidity zone water-releasing porous aggregate with polypropylene microfiber, and the dry mass ratio of the fine-grained high-humidity zone water-releasing porous aggregate to the polypropylene microfiber is 6:1 to 18:1; the functional premix is ​​formed by physically mixing water-treated low-humidity zone water-releasing porous aggregate with a portion of delayed-reaction magnesium oxide expansion agent, and the dry mass ratio of the low-humidity zone water-releasing porous aggregate to the portion of delayed-reaction magnesium oxide expansion agent is 45:4 to 70:8.

[0015] By adopting the above technical solution, the present invention utilizes the water film attached to the surface of porous fine aggregate as a bonding medium and physical isolation layer, and promotes the unbundling of polypropylene microfibers by means of frictional collision of rigid inorganic particles; on this basis, the delayed reaction magnesium oxide expansion agent is more likely to adhere to the water-releasing porous fine aggregate in the lower humidity area, which forms a local water supply microenvironment, which helps to improve the conversion of the later expansion reaction.

[0016] Secondly, this invention provides a crack-resistant construction method for high-toughness cement concrete pavement materials, employing the following technical solution: A crack-resistant construction method for high-toughness cement concrete pavement materials includes the following steps: S1: Weigh each raw material component according to the weight parts of the components; S2: Soak and pre-wet the porous fine aggregates that release water in high humidity areas and the porous fine aggregates that release water in low humidity areas, and control the surface free water content; S3: Microfiber carrier mixture and functional premix are prepared by using partially pre-wetted porous fine aggregate with water release in high humidity zone and porous fine aggregate with water release in low humidity zone, respectively. S4: The minimum mixing energy calibration value per unit mass is obtained by calibrating the main mixer under no-load and with material operation. S5: Add the base materials, excluding the functional premix, microfiber carrier mixture, short-scale macro polyolefin fiber, long-scale macro polyolefin fiber, and the remaining unmixed delayed-reaction magnesium oxide expansion agent, into the main mixer for dry mixing; then add the first part of liquid components for wet mixing, monitor the stirring power to reach the wet mixing peak and then drop, add the functional premix and accumulate the premix dispersion energy; S6: Alternately add the remaining second part of the liquid component and the microfiber carrier mixture. After the addition is complete, stop the accumulation of premix dispersion energy and accumulate fiber dispersion energy. S7: Based on the drop and stabilization characteristics of the main mixer's operating power as the timing trigger threshold, short-scale macroscopic polyolefin fibers and long-scale macroscopic polyolefin fibers are added in staggered shifts until the total actual post-mixing energy meets the unloading control standard before unloading.

[0017] By adopting the above technical solution, this invention uses equipment operating power as a rheological reference index to construct a feeding control process based on time sequence and dispersion energy accumulation. Pre-prepared premixed carriers are used instead of direct dry powder addition, reducing the probability of material agglomeration. Subsequently, a basic rheology is established to provide a shear transfer medium for the main slurry. During the mixing operation, the system uses the decline characteristics of equipment power as feedback on the material wetting state, employing energy accumulation instead of single time control. The aim is to allow the fibers to undergo shearing in a slurry with a certain viscosity and thus disperse them, thereby reducing mechanical wear on the fiber surface caused by ineffective excessive stirring.

[0018] Preferably, in step S2, the high-humidity zone water-releasing porous fine aggregate and the low-humidity zone water-releasing porous fine aggregate are pre-wetted in water at 10-30°C for 12-24 hours. After draining, the surface free water content of the coarse particles in the high-humidity zone water-releasing porous fine aggregate is controlled to be no more than 0.3% of the dry weight, the surface free water content of the fine particles in the high-humidity zone water-releasing porous fine aggregate is no more than 0.4% of the dry weight, and the surface free water content of the low-humidity zone water-releasing porous fine aggregate is no more than 0.8% of the dry weight. In step S3, the functional premix is ​​prepared by physically mixing the pre-wetted and drained low-humidity zone water-releasing porous fine aggregate with a portion of the delayed-reaction magnesium oxide expanding agent in a mixer for 30-60 seconds. The microfiber carrier mixture is prepared by first putting the pre-wetted and drained fine particles in the high-humidity zone water-releasing porous fine aggregate into a mixing hopper, uniformly sprinkling all the polypropylene microfibers within 15-30 seconds, and continuing to mix for 20-40 seconds.

[0019] By adopting the above technical solution, the pretreatment process defines the moisture content and premixing parameters of the porous aggregate. Controlling the surface free water content is primarily to prevent excess moisture from adversely affecting the overall water-cement ratio of the matrix; combined with a specific range of physical mixing time, it can promote the initial adhesion and dispersion of functional powders and microfibers on the surface of the rigid aggregate to a certain extent.

[0020] Preferably, in step S5, the first liquid component accounts for 75% of the total mass of the liquid component, and the second liquid component accounts for 25% of the total mass of the liquid component; in step S6, the overlap time of the alternating addition of the second liquid component and the microfiber carrier mixture is controlled between 50% and 100%.

[0021] By adopting the above technical solution, this invention uses a stepwise liquid addition strategy to regulate the rheological behavior of the slurry. The initial 75% liquid component promotes the formation of a basic rheological form with high yield stress; then, the remaining 25% liquid and carrier are added alternately, maintaining the basic fluidity of the slurry while utilizing the shear resistance inherent in the slurry to assist the fiber network in spatial distribution.

[0022] Preferably, in step S7, the control logic for staggered addition is as follows: short-scale macroscopic polyolefin fibers are sprinkled in within 15-25s, and the stable power before addition and the peak power formed after addition are recorded; the operating power of the main mixer is continuously monitored, and when the power drops to the sum of the stable power and 30%-60% of the maximum power increment, and is maintained for 3-8s, long-scale macroscopic polyolefin fibers are added within 20-35s and stirring is continued until discharge.

[0023] By adopting the above technical solution, the staggered feeding mechanism is mainly based on real-time feedback of rheological power. Since the addition of fibers of different scales leads to an increase in the apparent viscosity of the slurry and the generation of power peaks, this method uses a 30%-60% incremental decline threshold and a 3-8s stabilization period as the basis for inferring that the fibers of the previous scale have basically completed wetting and unbundling. Introducing the next scale fiber at this stage can effectively avoid the physical entanglement and agglomeration phenomena caused by the simultaneous addition of multiple scale fibers.

[0024] Preferably, in step S7, the total actual post-mixing energy at the time of unloading is 1.00-1.20 times the minimum unit mass post-mixing energy calibration value, and the system energy distribution satisfies that the premix dispersion energy accounts for 30%-45% of the total actual post-mixing energy, and the fiber dispersion energy accounts for 55%-70% of the total actual post-mixing energy.

[0025] By adopting the above technical solution, this step limits the total input energy and the dispersion energy at each stage. Controlling the total post-mixing energy within 1.00-1.20 times the calibrated value helps maintain the macroscopic homogeneity of the system and reduces unnecessary energy-consuming operations. The corresponding energy distribution ratio takes into account both the early dispersion and coating of inorganic functional premixes and the later spatial networking of organic multi-scale fibers, providing a foundation for obtaining relatively stable material properties.

[0026] This invention provides a high-toughness cement concrete pavement material and a crack-resistant construction method. It has the following beneficial effects: 1. This invention combines calcium sulfoaluminate-based expanding agents, fast-reacting and slow-reacting magnesium oxide expanding agents, with porous fine aggregates of different pore sizes that release water in high and low humidity zones. Utilizing the differences in water-binding force among the porous fine aggregates of different pore sizes, water is released sequentially at different stages of the decrease in relative humidity of the matrix, thereby triggering the hydration and expansion of the corresponding expanding agents and mitigating the volume shrinkage of pavement materials from the early to the long term.

[0027] 2. This invention uses pre-wetted porous fine aggregate as a physical unbinding carrier for fibers, and introduces fibers of different lengths and diameters sequentially and in staggered manner based on real-time feedback from the operating power of the mixing equipment. This feeding method reduces the probability of micro and macro fibers entanglement and agglomeration, helps to improve the dispersion uniformity of multi-scale fibers in the matrix, and has a positive effect on improving the overall toughness of pavement materials.

[0028] 3. This invention introduces the operating power and cumulative energy of the main mixer as control indicators in the construction method, and determines the wetting state of the material by monitoring rheological characteristics such as the drop in power increment. This quantitative time-triggered and energy distribution mechanism can avoid wear or breakage of the organic fiber surface caused by excessive mixing, while maintaining the homogeneity of the system, which is beneficial to ensuring the construction quality of concrete projects. Attached Figure Description

[0029] To more intuitively illustrate the prior art and this application, exemplary drawings are provided below. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing this application; for example, based on the technical concept disclosed in this application and the exemplary drawings, those skilled in the art are able to easily make conventional adjustments or further optimizations to the addition / reduction / classification, specific shapes, positional relationships, connection methods, size ratios, etc. of certain units (components).

[0030] Figure 1 This is a schematic diagram of the power feedback control in the multi-scale fiber cascade addition stage of the present invention. Detailed Implementation

[0031] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] In the description of this application: unless otherwise stated, "a plurality of" means two or more. The terms "first," "second," "third," etc., in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (e.g., they should not be construed as an emphasis on importance or order). Expressions such as "including," "comprising," and "having" also mean "not limited to" (certain units, components, materials, steps, etc.).

[0033] The terms used in this application, such as "upper," "lower," "left," "right," and "middle," are generally used to indicate the general relative positional relationship for the purpose of intuitive understanding by referring to the accompanying drawings, and are not absolute limitations on the positional relationship in the actual product.

[0034] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0035] The silicate cement used is commercially available PO 52.5 grade ordinary silicate cement.

[0036] The slag powder used is commercially available S95 grade granulated blast furnace slag powder.

[0037] The fly ash used is commercially available Class F, Grade I fly ash.

[0038] The silica fume used is commercially available fine silica fume with a silica mass fraction greater than 90%.

[0039] The core active component of calcium sulfoaluminate-based expanding agents is anhydrous calcium sulfoaluminate mineral phase, CAS number 12005-25-3, molecular formula 3CaO·3Al2O3·CaSO4, and specific surface area of ​​300 m². 2 / kg.

[0040] The fast-reaction magnesium oxide expanding agent, hereinafter referred to as MgO-A, has magnesium oxide as its main active ingredient. Its CAS number is 1309-48-4. It is prepared by calcining magnesite at 800℃ to 1000℃, with an effective magnesium oxide mass fraction of 88% and a citric acid color development and neutralization time of 60s.

[0041] The delayed-reaction magnesium oxide expander, hereinafter referred to as MgO-B, has magnesium oxide as its main active ingredient. Its CAS number is 1309-48-4. It is prepared by calcining magnesite at 1000℃ to 1200℃, with an effective magnesium oxide mass fraction of 85% and a citric acid color development and neutralization time of 150s.

[0042] The porous fine aggregates for water release in high humidity zones and low humidity zones were made from commercially available expanded shale sand, and were designated L1 and L2 respectively after screening. Except for differences in 24-hour water absorption rate and water release characteristics, their apparent density was 1400 kg / m³. 3 The bulk density is 850 kg / m³ 3 The compressive strength of the aggregate is 8 MPa, the mud content is 0.5%, and it contains no soluble organic matter. The 24-hour water absorption rate of L1 is 21%, and that of L2 is 23%. L1 releases 60% of its absorbed water when the relative humidity decreases from 98% to 90%, and 20% when the relative humidity decreases from 90% to 80%. L2 releases 25% of its absorbed water when the relative humidity decreases from 98% to 90%, and 55% when the relative humidity decreases from 90% to 80%. The remaining absorbed water is released under even lower relative humidity conditions or is residual water. The porous fine aggregate L1, which releases water in the high humidity zone, is sieved and separated into coarse-grained fine aggregate L1a with a particle size ranging from 1.18 mm to 4.75 mm, and fine-grained fine aggregate L1b with a particle size ranging from 0.60 mm to 1.18 mm.

[0043] The natural fine aggregate is commercially available natural river sand with a fineness modulus of 2.6.

[0044] The coarse aggregate is commercially available continuously graded crushed stone with a particle size range of 5mm to 20mm.

[0045] The main component of polypropylene microfibers is isotactic polypropylene, CAS number 9003-07-0. Its repeating unit structure is primarily a carbon-carbon backbone with propylene side groups. The polymerization method is homopolymerization. The weight-average molecular weight ranges from 200,000 to 300,000, the crystallinity is 65%, and the density is 0.91 g / cm³. 3 The fiber has a length of 9 mm, a single filament diameter of 20 μm, a tensile strength of 400 MPa, and an elastic modulus of 4.0 GPa.

[0046] Both short-scale and long-scale macroscopic polyolefin fibers are primarily composed of isotactic polypropylene (CAS number 9003-07-0). The repeating unit structure is mainly a propylene structure with a carbon-carbon backbone and methyl side groups. The polymerization method is homopolymerization. The weight-average molecular weight ranges from 250,000 to 350,000, the crystallinity is 70%, and the density is 0.91 g / cm³. 3 The short-scale fiber has a length of 30 mm, an equivalent diameter of 0.40 mm, an aspect ratio of 75, a tensile strength of 450 MPa, and an elastic modulus of 5.5 GPa. Its surface is textured and mechanically anchored. The long-scale fiber has a length of 45 mm, an equivalent diameter of 0.60 mm, an aspect ratio of 75, a tensile strength of 450 MPa, and an elastic modulus of 5.5 GPa. Its surface is deeply textured and mechanically anchored.

[0047] The active ingredient of polycarboxylate superplasticizer is a polycarboxylate ether comb copolymer, CAS number 27599-56-0. The main chain contains methacrylic acid structural units, and the side chains contain polyethylene glycol monomethyl ether structural units. The polymerization method is copolymerization. The weight-average molecular weight ranges from 30,000 to 50,000. The solid content is 20%, and the water reduction rate is 28%. When using, the polycarboxylate superplasticizer is 0.12% to 0.25% of the total mass of cement, slag powder, fly ash, and silica fume, based on the solid content. The amount of water introduced into the liquid superplasticizer is included in the effective mixing water.

[0048] The main component of the air-entraining agent is a rosin thermal polymer surfactant, with CAS number 61790-51-0 and a solid content of 10%.

[0049] Preparation Example 1: This preparation example provides a method for preparing microfiber carrier mixture F1, including the following steps: (1) The fine-grained, high-humidity, water-releasing porous fine aggregate L1b was pre-wetted in water at 10°C for 12 hours, and then drained for 60 minutes to control the free water on its surface to be 0.10% of its dry weight.

[0050] (2) According to the ratio of L1b dry mass to polypropylene microfiber mass of 6:1, first put the pre-wetted L1b into the mixing hopper, and then evenly sprinkle polypropylene microfiber within 15s.

[0051] (3) Then continue dry mixing for 20s, and use the rigid separation effect of inorganic porous particles to promote fiber unbundling and reduce the probability of fiber bundle aggregation to obtain microfiber carrier mixture F1.

[0052] Preparation Example 2: This preparation example provides a method for preparing microfiber carrier mixture F1, including the following steps: (1) The fine-grained, high-humidity, water-releasing porous fine aggregate L1b was pre-wetted in water at 20°C for 18 hours, and then drained for 30 minutes to control the free water on its surface to be 0.20% of its dry weight.

[0053] (2) According to the ratio of L1b dry mass to polypropylene microfiber mass of 12:1, first put the pre-wetted L1b into the mixing hopper, and then evenly sprinkle polypropylene microfiber within 20s.

[0054] (3) Then continue dry mixing for 30s, and use the rigid separation effect of inorganic porous particles to promote fiber unbundling and reduce the probability of fiber bundle aggregation to obtain microfiber carrier mixture F1.

[0055] Preparation Example 3: This preparation example provides a method for preparing microfiber carrier mixture F1, including the following steps: (1) The fine-grained, high-humidity, water-releasing porous fine aggregate L1b was pre-wetted in water at 30°C for 24 hours, and then drained for 15 minutes to control the surface free water to be 0.35% of the dry weight.

[0056] (2) According to the ratio of L1b dry mass to polypropylene microfiber mass of 18:1, first put the pre-wetted L1b into the mixing hopper, and then evenly sprinkle polypropylene microfiber within 30s.

[0057] (3) Then continue dry mixing for 40s, and use the rigid separation effect of inorganic porous particles to promote fiber unbundling and reduce the probability of fiber bundle aggregation to obtain microfiber carrier mixture F1.

[0058] Preparation Example 4: This preparation example provides a method for preparing a functional premix P, including the following steps: (1) Immerse the porous fine aggregate L2 with water release in the lower humidity area in water at 10°C for 12 hours to pre-wet it. After taking it out, drain it for 60 minutes to control the free water on its surface to be 0.2% of the dry weight.

[0059] (2) Based on dry mass, the pre-wetted and drained L2 and the delayed reaction magnesium oxide expansion agent MgO-B were physically mixed in a low shear mixer for 30s at a mass ratio of 45:4.

[0060] (3) Establish a close physical contact relationship and a neighboring distribution relationship between the two to obtain functional premix P.

[0061] Preparation Example 5: This preparation example provides a method for preparing a functional premix P, including the following steps: (1) Immerse the low humidity zone water-releasing porous fine aggregate L2 in water at 20°C for 18 hours to pre-wet it. After taking it out, drain it for 30 minutes to control the free water on its surface to be 0.4% of the dry weight.

[0062] (2) Based on dry mass, the pre-wetted and drained L2 and the delayed reaction magnesium oxide expansion agent MgO-B were physically mixed in a low shear mixer for 45s at a mass ratio of 55:6.

[0063] (3) Establish a close physical contact relationship and a neighboring distribution relationship between the two to obtain functional premix P.

[0064] Preparation Example 6: This preparation example provides a method for preparing a functional premix P, including the following steps: (1) Immerse the porous fine aggregate L2 with low humidity in water at 30°C for 24 hours, then drain for 15 minutes to control the free water on its surface to be 0.6% of the dry weight.

[0065] (2) Based on dry mass, the pre-wetted and drained L2 and the delayed reaction magnesium oxide expansion agent MgO-B were physically mixed in a low shear mixer for 60s at a mass ratio of 70:8.

[0066] (3) Establish a close physical contact relationship and a neighboring distribution relationship between the two to obtain functional premix P. Example

[0067] This embodiment provides a crack-resistant construction method for high-toughness cement concrete pavement materials, including the following steps: S1: According to the concrete mix proportion per cubic meter, accurately weigh out 300 kg of silicate cement, 50 kg of slag powder, 30 kg of fly ash, 15 kg of silica fume, 18 kg of calcium sulfoaluminate expansive agent, 5 kg of fast-reacting magnesium oxide expansive agent, 9 kg of slow-reacting magnesium oxide expansive agent, 620 kg of natural fine aggregate, 1040 kg of coarse aggregate, 140 kg of effective mixing water, 2.8 kg of polycarboxylate superplasticizer (the solid content of the polycarboxylate superplasticizer is 20%, and its water content is included in the effective mixing water), 0.4 kg of air-entraining agent, 0.7 kg of polypropylene microfiber, 2.2 kg of short-scale macroscopic polyolefin fiber, and 2.5 kg of long-scale macroscopic polyolefin fiber. Weigh out 35 kg of dry, high-humidity zone water-releasing porous fine aggregate, and sieve it into 26 kg of coarse particles and 9 kg of fine particles. Weigh 55 kg of dry, low-humidity porous fine aggregate. Based on the 24-hour water absorption rate of L1 being 21% and L2 being 23%, the total internal curing water carried by L1 and L2 in Example 1 is 20.00 kg. The total mass of cement, slag powder, fly ash, and silica fume is 395 kg. The amount of delayed reaction magnesium oxide expansion agent is 9 kg. WIC / (0.035Mb+0.447MB)=20.00 / (0.035×395+0.447×9)=1.12, which meets the control range of 1.05 to 1.35.

[0068] S2: Soak the coarse-grained, high-humidity zone water-releasing porous fine aggregate, the fine-grained, high-humidity zone water-releasing porous fine aggregate, and the low-humidity zone water-releasing porous fine aggregate separately in water for 18 hours, maintaining the water temperature at 20℃. After draining for 30 minutes, control the surface free water content of the coarse-grained aggregate to be no more than 0.3% of its dry weight, the surface free water content of the fine-grained aggregate to be 0.2% of its dry weight, and the surface free water content of the low-humidity zone to be 0.4% of its dry weight.

[0069] S3: 55 kg of pre-wetted and drained low-humidity zone water-releasing porous fine aggregate and 5 kg of delayed-reaction magnesium oxide expanding agent are physically mixed in a low-shear mixer for 40 s to obtain a functional premix. 9 kg of pre-wetted and drained fine-grained high-humidity zone water-releasing porous fine aggregate is added to a mixing hopper, and all polypropylene microfibers are evenly sprinkled in within 20 s. Dry mixing continues for 30 s to obtain a microfiber carrier mixture.

[0070] S4: The minimum unit mass mixing energy calibration value that meets macroscopic homogeneity and is free of fiber agglomeration is obtained by calibrating the twin-shaft mixer under no-load and with material operation before production.

[0071] S5: Add coarse aggregate, natural fine aggregate, pre-wetted coarse-grained high-humidity porous fine aggregate, and dry powder to the main mixer and dry mix for 30 seconds. The dry powder includes all silicate cement, slag powder, fly ash, silica fume, calcium sulfoaluminate expansive agent, fast-reacting magnesium oxide expansive agent, and the remaining unmixed 4 kg of delayed-reacting magnesium oxide expansive agent. Pre-mix the effective mixing water, polycarboxylate superplasticizer, and air-entraining agent into a liquid component, and divide the liquid component into a first liquid component and a second liquid component. The first liquid component accounts for 75% of the total mass of the liquid component, and the second liquid component accounts for 25%. First, add the first liquid component to the main mixer for wet mixing. After monitoring the mixing power to detect the wet mixing peak and its subsequent decline, confirming the formation of the basic rheology, add the functional premix and begin accumulating the premix dispersion energy.

[0072] S6: Within 20 seconds, alternately add the second liquid component and the microfiber carrier mixture to the main mixer, with an overlap time of 80%. After addition is complete, stop the accumulation of premix dispersion energy and start accumulating fiber dispersion energy, and continue stirring for 30 seconds.

[0073] S7: Within 20 seconds, add short-scale macroscopic polyolefin fibers, recording the stable power before addition and the peak power after addition due to slurry thickening. Continuously monitor the decrease in the main mixer's operating power. When the power decreases to the sum of the stable power and 45% of the maximum power increment, and remains stable for 5 seconds, confirm that the short-scale fibers have been completely wetted and unbundled. Then, within 25 seconds, add long-scale macroscopic polyolefin fibers and continue stirring for 35 seconds before discharging. At discharge, control the total actual post-mixing energy to be 1.10 times the minimum calibrated value, with the premix dispersion energy accounting for 35% of the total post-mixing energy and the fiber dispersion energy accounting for 65%. Example

[0074] This embodiment provides a crack-resistant construction method for high-toughness cement concrete pavement materials, including the following steps: S1: According to the concrete mix proportions per cubic meter, accurately weigh out 320 kg of silicate cement, 45 kg of slag powder, 25 kg of fly ash, 15 kg of silica fume, 24 kg of calcium sulfoaluminate expansive agent, 7 kg of fast-reacting magnesium oxide expansive agent, 7 kg of slow-reacting magnesium oxide expansive agent, 600 kg of natural fine aggregate, 1080 kg of coarse aggregate, 150 kg of effective mixing water, 3.0 kg of polycarboxylate superplasticizer (the solid content of the polycarboxylate superplasticizer is 20%, and its water content is included in the effective mixing water), 0.5 kg of air-entraining agent, 0.9 kg of polypropylene microfiber, 3.0 kg of short-scale macroscopic polyolefin fiber, and 1.6 kg of long-scale macroscopic polyolefin fiber. Weigh out 45 kg of dry, high-humidity zone water-releasing porous fine aggregate, and sieve it into 35 kg of coarse particles and 10 kg of fine particles. Weigh 45 kg of dry, low-humidity porous fine aggregate. Based on the 24-hour water absorption rate of L1 being 21% and L2 being 23%, the total internal curing water carried by L1 and L2 in Example 2 is 19.80 kg. The total mass of cement, slag powder, fly ash, and silica fume is 405 kg. The amount of delayed reaction magnesium oxide expansion agent is 7 kg. WIC / (0.035Mb+0.447MB)=19.80 / (0.035×405+0.447×7)=1.14, which meets the control range of 1.05 to 1.35.

[0075] S2: Using the pre-wetting method of Example 1, control the surface free water content of coarse particles to 0.1%, the surface free water content of fine particles to 0.1%, and the surface free water content of the lower humidity area to 0.2%.

[0076] S3: 45 kg of low-humidity zone water-releasing porous fine aggregate and 4 kg of delayed-reaction magnesium oxide expansion agent are mixed for 30 s to obtain a functional premix. 10 kg of fine-grained high-humidity zone water-releasing porous fine aggregate is added to the mixing hopper and 0.9 kg of microfiber is sprinkled in within 15 s and mixed for 20 s to obtain a microfiber carrier mixture.

[0077] S4: Perform minimum unit mass mixing energy calibration as in Example 1.

[0078] S5: In the same way as in Example 1, add the basic materials other than the premix and carrier mixture and dry mix for 20 seconds. Then, according to the method in Example 1, divide the liquid component into a first liquid component and a second liquid component. After the dry mixing is completed, add the first liquid component and wet mix. After confirming the formation of the basic rheology, add the functional premix and start accumulating the premix dispersion energy. The dry powder contains the remaining 3 kg of delayed reaction magnesium oxide expansion agent.

[0079] S6: Within 15 seconds, alternately add the second liquid component and the microfiber carrier mixture to the main mixer, with an overlap time of 50%. After the addition is complete, stop the accumulation of premix dispersion energy and start accumulating fiber dispersion energy, and continue stirring for 20 seconds.

[0080] S7: Sprinkle short-scale macroscopic polyolefin fibers within 15 seconds and record the stable power and peak power before addition. When the power drops to the sum of the stable power and 30% of the maximum power increment and stabilizes for 3 seconds, add long-scale macroscopic polyolefin fibers within 20 seconds and continue stirring for 25 seconds. At discharge, control the total post-mixing energy to be equal to 1.00 times the minimum calibration value, with the premix dispersion energy accounting for 45% of the total post-mixing energy and the fiber dispersion energy accounting for 55% of the total post-mixing energy. Example

[0081] This embodiment provides a crack-resistant construction method for high-toughness cement concrete pavement materials, including the following steps: S1: According to the concrete mix proportions per cubic meter, accurately weigh 285 kg of silicate cement, 60 kg of slag powder, 40 kg of fly ash, 18 kg of silica fume, 12 kg of calcium sulfoaluminate expansive agent, 4 kg of fast-reacting magnesium oxide expansive agent, 12 kg of slow-reacting magnesium oxide expansive agent, 660 kg of natural fine aggregate, 1000 kg of coarse aggregate, 138 kg of effective mixing water, 4.0 kg of polycarboxylate superplasticizer (the solid content of the polycarboxylate superplasticizer is 20%, and its water content is included in the effective mixing water), 0.3 kg of air-entraining agent, 0.6 kg of polypropylene microfiber, 1.4 kg of short-scale macroscopic polyolefin fiber, and 3.3 kg of long-scale macroscopic polyolefin fiber. Weigh 25 kg of dry, high-humidity zone water-releasing porous fine aggregate, and sieve it into 17.5 kg of coarse particles and 7.5 kg of fine particles. Weigh 70 kg of dry, low-humidity porous fine aggregate. Based on the 24-hour water absorption rate of L1 being 21% and L2 being 23%, the total internal curing water carried by L1 and L2 in Example 3 is 21.35 kg. The total mass of cement, slag powder, fly ash, and silica fume is 403 kg. The amount of delayed reaction magnesium oxide expansion agent is 12 kg. WIC / (0.035Mb+0.447MB)=21.35 / (0.035×403+0.447×12)=1.10, which meets the control range of 1.05 to 1.35.

[0082] S2: According to the pre-wetting method of Example 1, the surface free water content of coarse particles is controlled at 0.3%, the surface free water content of fine particles is controlled at 0.35%, and the surface free water content of the lower humidity area is controlled at 0.6%.

[0083] S3: A functional premix is ​​prepared by mixing 70 kg of low-humidity zone water-releasing porous fine aggregate with 8 kg of delayed-reaction magnesium oxide expansion agent for 60 s. A microfiber carrier mixture is prepared by adding 7.5 kg of fine-grained high-humidity zone water-releasing porous fine aggregate into a mixing hopper and sprinkling 0.6 kg of microfiber into it within 30 s and mixing for 40 s.

[0084] S4: Perform minimum unit mass mixing energy calibration as in Example 1.

[0085] S5: In the same way as in Example 1, the basic materials are added and dry-mixed for 35 seconds, and the liquid components are divided into the first liquid component and the second liquid component according to the method of Example 1. After the dry mixing is completed, the first liquid component is added for wet mixing. After confirming the formation of rheology, the functional premix is ​​added late and the dispersion energy of the premix is ​​accumulated. The remaining dry powder contains 4 kg of delayed-reaction magnesium oxide expansion agent.

[0086] S6: The second liquid component and the microfiber carrier are added alternately within 30s, with an overlap time of 100%. Then, the accumulation of premixed dispersion energy is terminated, and the accumulation of fiber dispersion energy is started and stirred for 35s.

[0087] S7: Sprinkle in short-scale fibers within 25 seconds. When the power drops to the sum of the stable power and 60% of the maximum power increment and stabilizes for 8 seconds, add long-scale fibers within 35 seconds and continue stirring for 50 seconds. When unloading, control the total post-mixing energy to be equal to 1.20 times the minimum calibration value, with the premix dispersion energy accounting for 30% of the total energy and the fiber dispersion energy accounting for 70%. Example

[0088] This embodiment provides a crack-resistant construction method for high-toughness cement concrete pavement materials, including the following steps: S1 to S6 are the same as in Example 1. The raw material addition ratio and the pre-process are exactly the same in this example. The only difference is the power control condition for the addition of multi-scale fibers.

[0089] S7: Sprinkle short-scale macroscopic polyolefin fibers within 20 seconds, and record the stable power and peak power before addition. Continuously monitor the main mixer power. When the power drops to the sum of the stable power and 60% of the maximum power increment and remains stable for only 3 seconds, quickly add long-scale macroscopic polyolefin fibers within 25 seconds. Continue mixing until the discharge energy control conditions are met, then discharge the material. The total actual post-mixing energy is still controlled at 1.10 times the minimum calibrated value, with the premix dispersion energy accounting for 35% of the total post-mixing energy and the fiber dispersion energy accounting for 65% of the total post-mixing energy. Example

[0090] This embodiment provides a crack-resistant construction method for high-toughness cement concrete pavement materials, including the following steps: S1: Adjust the ratio of microfibers to fine-grained, high-humidity zone water-releasing porous aggregate to the design upper limit. Specifically, take 0.6 kg of polypropylene microfibers and sieve to prepare 10.8 kg of fine-grained, high-humidity zone water-releasing porous aggregate. The dry mass ratio of the two is set to 18:1. The total amount of high-humidity zone water-releasing porous aggregate remains 35 kg, of which the coarse-grained high-humidity zone water-releasing porous aggregate is adjusted to 24.2 kg and the fine-grained high-humidity zone water-releasing porous aggregate is adjusted to 10.8 kg. Except for the above adjustments to the amount of polypropylene microfibers and the coarse-fine particle size distribution of the high-humidity zone water-releasing porous aggregate, the amounts of other cementing materials, expanding agents, natural fine aggregates, coarse aggregates, effective mixing water, admixtures, short-scale macroscopic polyolefin fibers, and long-scale macroscopic polyolefin fibers are the same as in Example 1.

[0091] S2: Perform aggregate pre-wetting and free water control in the same manner as in Example 1.

[0092] S3: 10.8 kg of pre-wetted fine-grained aggregate is added to the mixing hopper, and 0.6 kg of microfiber is evenly and slowly sprinkled in within 30 seconds and then dry-mixed at high intensity for 40 seconds. The rigid particles improve the spatial separation between fiber bundles and reduce the probability of microfiber agglomeration, thus obtaining a microfiber carrier mixture. The preparation of the remaining functional premixes is the same as in Example 1.

[0093] S4 to S7: The subsequent feeding sequence, energy monitoring and discharge steps of the main mixer are exactly the same as in Example 1.

[0094] Comparative Example 1: Compared to Example 1, the difference lies in the absence of a microfiber carrier mixture. Specifically, fine-grained, high-humidity, water-releasing porous aggregate was added according to the conventional process, while polypropylene microfibers were directly added to the main mixer along with silicate cement during the dry mixing stage of the base materials. The rigid insertion of inorganic porous particles was not used for dry-state mechanical forced unbundling. All other aspects were the same.

[0095] Comparative Example 2: Compared to Example 1, the difference lies in the absence of a functional premix. Specifically, the porous fine aggregate with low humidity release and the corresponding delayed-reaction magnesium oxide expander were directly added to the main mixer during the dry mixing stage. No close physical contact or proximity distribution relationship was established between the internal curing water supply and the delayed-reaction expansion reaction sites. All other aspects remained the same.

[0096] Comparative Example 3: Compared to Example 1, the difference lies in the absence of a cascade feeding strategy based on rheological power feedback. Specifically, during the cumulative fiber dispersion energy stage, short-scale macroscopic polyolefin fibers and long-scale macroscopic polyolefin fibers were simultaneously added to the main mixer and continuously stirred. The wet mixing and entanglement process of long and short fibers and the mechanical trapping chain were not interrupted by observing the drop in power peak. All other aspects remained the same.

[0097] Comparative Example 4: Compared to Example 1, the difference lies in the change of the timing of the addition of the functional premix and the control of energy distribution cutting. Specifically, the prepared functional premix is ​​first added to the main mixer, so that it undergoes intense dry and wet mixing throughout the entire cycle together with the coarse and fine aggregates. The total post-mixing energy is not forcibly divided into two stages: premix dispersion energy and fiber dispersion energy, resulting in the premix structure being subjected to excessive redispersion shear. Everything else is the same.

[0098] Comparative Example 5: Compared to Example 1, the difference lies in the change of the multi-stage internal curing and expansion agent compound system. Specifically, the fast-reacting magnesium oxide expansion agent and the slow-reacting magnesium oxide expansion agent were removed and replaced with calcium sulfoaluminate expansion agents in equal mass fractions. This caused the original early, middle and late-stage full-age shrinkage compensation deformation source to degenerate into a single early compensation mechanism. Everything else remained the same.

[0099] Test Example 1: Experimental Description: This test case is used to verify the effectiveness and feasibility of the segmented cascade feeding process based on rheological power feedback in monitoring changes in the rheological properties of the slurry and controlling the timing of fiber addition.

[0100] Experimental steps: A high-precision digital power meter is connected in series at the input end of the main shaft motor of the twin-shaft mixer. The data acquisition frequency is set to 10Hz and synchronously connected to the host computer data recording system to continuously extract the instantaneous active power of the mixing cycle.

[0101] According to the proportions of Examples 1 and 4 and the previous process, the mixer was run. After the basic powder was aggregated into a slurry and the premixed material dispersion energy was accumulated, the reference power of the mixing equipment for stable operation with the material was recorded.

[0102] Short-scale macroscopic polyolefin fibers were added to the main mixer, and the initial addition point was marked in the system. The macroscopic viscosity increase caused by the fiber incorporation into the base rheology was monitored, and the peak operating power at this stage was extracted.

[0103] Track the power drop curve after the peak power. For Example 1, record the time span during which the power drops to the sum of the stable reference power and 45% of the maximum power increment, and is maintained in this state for 5 seconds. For Example 4, record the time span during which the power drops to the sum of the stable reference power and 60% of the maximum power increment, and is maintained in this state for 3 seconds.

[0104] When the corresponding set power drop condition is triggered, long-scale macroscopic polyolefin fibers are introduced, and subsequent stirring power changes are recorded until the total actual post-mixing energy control requirements are met, at which point unloading is performed and power data acquisition stops.

[0105] The experimental data are shown in Table 1: Table 1: Test results of stirring kinetic characteristic parameters in Examples 1 and 4 Test object Stable reference power (kW) Peak power (kW) after short fiber addition Target trigger power threshold (kW) Peak time (s) Time (s) for the value to fall back to the threshold and stabilize Final stable power (kW) before unloading Example 1 31.84 46.21 38.31 11.3 24.6 39.52 Example 4 32.15 47.08 41.11 10.7 14.2 41.37 According to Table 1 and Figure 1 According to the data, in Examples 1 and 4, the operating power of the mixer increased after the addition of short-scale macroscopic polyolefin fibers, reaching peak power at 11.3s and 10.7s, respectively. This phenomenon indicates that after the short-scale macroscopic polyolefin fibers enter the basic rheological system, they occupy part of the slurry flow space, increase the slurry-fiber interface friction, and form an initial spatial network, thereby increasing the macroscopic stirring shear resistance of the mixture. The above-mentioned power peak change can serve as a reference signal for judging the mixing state of short-scale macroscopic polyolefin fibers and the change in rheological resistance, demonstrating the operability of using stirring power feedback to monitor rheological changes during the fiber addition stage.

[0106] In Example 1, the power drop-off trigger threshold was set as the sum of the stable reference power and 45% of the maximum power increment, requiring continuous stability for 5 seconds. The time taken for the power to drop back to the threshold and stabilize was 24.6 seconds. In Example 4, the trigger threshold was set as the sum of the stable reference power and 60% of the maximum power increment, requiring only continuous stability for 3 seconds. The time taken for the power to drop back to the threshold and stabilize was 14.2 seconds. It is evident that the triggering conditions in Example 1 are more stringent than those in Example 4, and the addition time of the long-scale macroscopic polyolefin fibers is relatively delayed. This difference reflects that different power drop-off thresholds and stabilization times affect the timing of the addition of long-scale macroscopic polyolefin fibers, thereby affecting the wetting, dispersion, and rheological adaptation of short-scale macroscopic polyolefin fibers before entering the next stage of mixing.

[0107] Comparing the final stable power before unloading, Example 1 had a power of 39.52 kW, lower than Example 4's 41.37 kW. Under the condition that the amount of long-scale macroscopic polyolefin fiber added remained consistent with the main formulation ratio, the lower final stable power of Example 1 indicates that its mixture exhibited relatively low sustained shear resistance before unloading. Combined with its lower trigger threshold and longer stable maintenance time, it can be concluded that the short-scale macroscopic polyolefin fibers in Example 1 underwent a relatively sufficient dispersion and rheological adaptation process before the addition of long-scale macroscopic polyolefin fibers, which helps reduce the probability of local entanglement and mechanical trapping between fibers of different scales.

[0108] In Example 4, due to the use of a higher power drop-off trigger threshold and a shorter stabilization time, long-scale macroscopic polyolefin fibers entered the mixing system earlier. Based on the relatively high final stable power before unloading, it can be inferred that under these process conditions, there is still a high fiber-slurry frictional resistance within the mixture, and the possibility of local entanglement between fibers of different scales is relatively increased. These results indicate that using the power peak drop-off degree and stabilization time as cascade feeding control parameters helps to adjust the addition sequence of multi-scale fibers and reduce the risk of fiber agglomeration.

[0109] Test Example 2: Experimental Description: This test case is used to verify the relative humidity evolution law and corresponding shrinkage compensation physical deformation behavior of the low water-cement ratio system in each stage of hardening under the synergistic effect of the internal water supply system constructed by porous aggregate with high and low humidity zones and multi-stage expansion agent.

[0110] Experimental steps: The mixtures prepared in Examples 1, 2, and 3 were used to cast prism specimens with dimensions of 100mm × 100mm × 400mm. During the molding process, a calibrated miniature capacitive temperature and humidity composite sensor and a frameless resistive strain gauge were fixed to the geometric center of the mold using a special bracket, ensuring that the sensor probes were fully encased in the surrounding concrete slurry.

[0111] The molded specimens were placed in a constant temperature and humidity test chamber with a temperature set at 20±2℃ and a relative humidity of 60±5%. Immediately after molding, the exposed surfaces of the specimens were covered with plastic film, and the specimens were allowed to stand for 24 hours before demolding. After demolding, an epoxy resin sealing coating was immediately applied to the surface of each specimen to isolate the exchange of moisture between the interior and exterior environments, thus establishing test conditions that simulate the self-drying environment inside the actual structure.

[0112] Connect the lead wires of the pre-embedded sensor to the multi-channel static resistance strain gauge and the multi-point temperature and humidity monitoring and recording system. Set the sampling interval of the data acquisition software to 2 hours, and continuously collect the raw data of internal relative humidity and micro-strain from the time of adding water and mixing to 90 days of age.

[0113] During the test run, ambient temperature baseline parameters were monitored simultaneously for sensor temperature compensation correction. The collected raw micro-strain data were converted into self-drying shrinkage and compensated expansion strain values. Data processing defined positive values ​​as expansion strain and negative values ​​as shrinkage strain. Data at specified age points were periodically exported for summarization and comparison.

[0114] The experimental data are shown in Table 2. Each group had at least three parallel specimens. The internal relative humidity and internal micro-strain of the specimens in Table 2 are the average values ​​of the test results from the parallel specimens. Table 2: Test results of internal relative humidity and shrinkage compensation strain in Examples 1 to 3 Test object Age (days) Internal relative humidity (%) Micro-strain (με) inside the specimen Example 1 3 96.4 +42.1 Example 1 7 94.2 +68.5 Example 1 28 89.7 +51.3 Example 1 60 85.1 +34.8 Example 1 90 82.6 +27.2 Example 2 3 97.8 +56.3 Example 2 7 95.5 +84.1 Example 2 28 91.3 +63.4 Example 2 60 87.2 +45.9 Example 2 90 85.4 +36.5 Example 3 3 95.1 +33.8 Example 3 7 92.6 +52.4 Example 3 28 86.8 +76.1 Example 3 60 81.4 +82.5 Example 3 90 78.9 +75.3 According to the data in Table 2, the relative humidity inside the specimens of Examples 1, 2, and 3 remained above 92% during the 3-7 day period, and the internal micro-strain of the specimens was positive and increased. This result indicates that under the sealed test conditions, the internal humidity of each example remained at a high level in the early stage, and a certain degree of positive compensation deformation was formed. This phenomenon may be related to the release of moisture from the porous fine aggregate in the high humidity zone during the high relative humidity stage, and the participation of calcium sulfoaluminate-based expansion agents and fast-reacting magnesium oxide expansion agents in early hydration expansion. Among them, the internal micro-strain of Example 2 at 7 days was +84.1 με, higher than that of Examples 1 and 3, indicating that its proportioning design biased towards early crack prevention showed a more significant effect in early compensation deformation.

[0115] During the 28-90 day age period, the internal relative humidity of Examples 1, 2, and 3 all decreased with increasing age, indicating that continuous moisture consumption and self-drying processes still exist within the low water-cement ratio system. The internal micro-strain of Examples 1 and 2 gradually decreased after 7 days, but remained at +27.2 με and +36.5 με, respectively, at 90 days. This result suggests that under conventional or early-stage crack-prevention formulations, the early-formed compensating deformation can still retain some positive strain reserves in the middle and later stages, and to some extent offset subsequent self-shrinkage deformation.

[0116] The test results of Example 3 show that its internal relative humidity at 28 days, 60 days, and 90 days was 86.8%, 81.4%, and 78.9%, respectively, which was lower than the internal relative humidity at the corresponding ages in Examples 1 and 2. Meanwhile, its internal micro-strain did not continue to decrease after 28 days, but increased from +76.1 με at 28 days to +82.5 με at 60 days, and remained at +75.3 με at 90 days. These results indicate that Example 3 still has a significant positive compensation deformation contribution in the middle and later stages. Considering the high proportion of water-releasing porous fine aggregate and delayed-reaction magnesium oxide expanding agent in the lower humidity zone of Example 3, it can be considered that this phenomenon may be related to the release of moisture by the water-releasing porous fine aggregate in the lower humidity zone during the lower internal relative humidity stage, and the continued hydration and expansion of the delayed-reaction magnesium oxide expanding agent in the middle and later stages.

[0117] Further combining the preparation method of functional premixes, the close physical contact and adjacent distribution relationship between the water-releasing porous fine aggregate in the lower humidity zone and the delayed-reaction magnesium oxide expansive agent facilitates the preferential supply of moisture released in the lower humidity zone to the adjacent delayed-reaction magnesium oxide expansive agent, thereby improving the effectiveness of deformation compensation in the middle and later stages. Therefore, the results shown in Table 2 support the existence of a staged synergistic effect among the water-releasing porous fine aggregate in the high humidity zone, the water-releasing porous fine aggregate in the lower humidity zone, the calcium sulfoaluminate expansive agent, the fast-reaction magnesium oxide expansive agent, and the delayed-reaction magnesium oxide expansive agent, which can regulate the internal humidity evolution and shrinkage compensation deformation of low water-cement ratio concrete at different ages.

[0118] Test Example 3: Experimental Description: This test example is used to verify the technical effects of using porous aggregates as microfiber carriers for dry forced unbundling, and controlling the mixing energy distribution through cascade feeding sequence, in improving the dispersion uniformity of low-density polypropylene microfibers, eliminating macroscopic agglomeration defects, and maintaining the stable rheological properties of the mixture.

[0119] Experimental steps: For the concrete mixtures prepared in Examples 1, 5, Comparative Example 1 and Comparative Example 3, when the main mixer enters the unloading process, 10 liters of the mixture samples are taken at three time points: the initial, middle and final unloading points. These samples are numbered as the initial subsample, the middle subsample and the final subsample, respectively. Each subsample is used for fiber recovery rate testing. A portion of the mixture from each subsample is then mixed evenly and used for slump, spread and the number of visible fiber agglomerates on the surface testing.

[0120] The mixed sample used for slump and spread tests was placed in three layers into a standard slump cone. The cone was tamped down according to specifications and then lifted steadily and vertically. The difference between the highest point of the slump and the height of the cone was measured to obtain the initial slump value of the mixture. Subsequently, the two mutually perpendicular diameters of the slump's bottom surface after spread were measured, and their arithmetic mean was taken as the spread value.

[0121] After the slump test is completed, the surface of the slump body and its surrounding extended area are carefully inspected and the number of visible polypropylene microfiber aggregates is counted by visual inspection.

[0122] Five kilograms of the mixture sample were weighed from the initial, intermediate, and final samples, respectively. The mixture was first placed on a standard test sieve with a 5-millimeter aperture for low-pressure water washing and separation to retain coarse aggregate and macroscopic polyolefin fibers. The slurry-sand mixture under the sieve was then further washed and separated by a combination of 0.30 mm and 0.075 mm sieves to retain polypropylene microfibers and a small amount of fine particle residue.

[0123] Polypropylene microfibers in the retained material were collected by manual sorting and flotation-assisted separation. The collected polypropylene microfibers were dried in a 60°C drying oven to constant weight, and their dry mass was measured using a precision balance. The microfiber recovery rate was calculated based on the theoretical microfiber mass corresponding to a 5 kg sample. Simultaneously, the microfiber dispersion coefficient was calculated by considering the dispersion of the recovery rates at three sampling points: the initial, middle, and final stages of unloading. The closer the recovery rate at each sampling point is to the theoretical dosage ratio, and the smaller the dispersion among the three points, the higher the microfiber dispersion coefficient.

[0124] The experimental data are shown in Table 3. Each group had at least three parallel mixing batches. The slump, spread, microfiber dispersion coefficient, and visible fiber agglomerate count in Table 3 are the average values ​​of the parallel batch test results. This slump test is used to evaluate the relative differences in the rheological properties of the mixture under different mixing processes, and does not limit the actual slump for slipform paving construction; the actual slump can be adjusted to the construction requirements by adjusting the water-reducing agent dosage, sand ratio, and paving equipment parameters. Table 3: Test results of material denaturation and microfiber dispersion uniformity of the mixtures in the examples and comparative examples Test object Initial slump (mm) Expansion (mm) Microfiber dispersion coefficient (%) Number of visible fiber aggregates on the surface (individuals) Example 1 165 415 92.4 0 Example 5 170 430 94.7 0 Comparative Example 1 115 295 65.8 16 Comparative Example 3 130 340 78.3 7 According to the data in Table 3, the microfiber dispersion coefficients of Examples 1 and 5 were 92.4% and 94.7%, respectively, and no visible fiber agglomerates were observed on the surface of the mixture; their initial slump was 165 mm and 170 mm, respectively, and their spread was 415 mm and 430 mm, respectively. These results indicate that under the conditions of using fine-grained, high-humidity, water-releasing porous aggregate as the microfiber carrier and pre-dry mixing, the polypropylene microfibers are relatively uniformly dispersed in the mixture, while the mixture maintains relatively good flowability.

[0125] In both Examples 1 and 5, a microfiber carrier mixture was prepared before main stirring, allowing the polypropylene microfibers to first contact and mix with porous fine aggregates of a specific particle size and high moisture content. This treatment method may reduce the probability of polypropylene microfibers forming bundles and agglomerates in the early stages of feeding by mechanically separating and frictionally disturbing the porous fine aggregate particles. In Example 5, the mass ratio of porous carrier to polypropylene microfibers was relatively high, and its microfiber dispersion coefficient was slightly higher than that in Example 1, indicating that under the test conditions, increasing the separation effect of the carrier particles on the microfibers is beneficial to improving the dispersion uniformity of the microfibers.

[0126] Comparative Example 1 did not prepare a microfiber carrier mixture; instead, polypropylene microfibers were directly added to the main mixer along with cement and other base powders. Its microfiber dispersion coefficient was 65.8%, the number of visible fiber agglomerates on the surface was 16, and the initial slump and spread were reduced to 115 mm and 295 mm, respectively. These results indicate that without carrier pre-dispersion, polypropylene microfibers are more prone to forming localized agglomerations during feeding and wet mixing, thus affecting the uniformity and flowability of the mixture. The voids within the insufficiently dispersed fiber bundles may trap some slurry or free liquid phase, reducing the effective liquid phase involved in particle lubrication and slurry flow, thereby causing the mixture to exhibit higher flow resistance.

[0127] Comparative Example 3 retained the microfiber carrier mixture F1, but simultaneously added short-scale macro-polyolefin fibers and long-scale macro-polyolefin fibers to the main mixer during the cumulative fiber dispersion energy stage. Its microfiber dispersion coefficient was 78.3%, the number of visible fiber agglomerates on the surface was 7, and the initial slump and spread were 130 mm and 340 mm, respectively. Compared with Example 1, the above indicators of Comparative Example 3 were all reduced, indicating that pre-dispersion of the microfiber carrier alone is insufficient to completely avoid the risk of secondary entanglement or local agglomeration caused by the subsequent simultaneous addition of multi-scale fibers.

[0128] In Comparative Example 3, the short-scale and long-scale macro-polyolefin fibers were not added in a staggered manner according to the power fallback condition. This resulted in secondary trapping, overlapping, or local entanglement between the polypropylene microfibers already in the slurry and subsequent macro-fibers, reducing the spatial uniformity of fiber distribution at different scales and increasing the frictional resistance within the mixture. These results indicate that the combined use of microfiber carrier pre-dispersion and power feedback-based cascade feeding timing control helps improve the dispersion state of multi-scale fibers in low water-to-binder ratio mixtures and helps maintain the stability of the mixture's rheological properties.

[0129] Test Example 4: Experimental Description: This test case is used to verify the comprehensive crack resistance performance of the relay crack-resistant network composed of microfibers and macroscopic dual-scale fibers combined with a multi-stage expansion agent shrinkage compensation system when facing plastic shrinkage and drying shrinkage stress.

[0130] Experimental steps: The mixtures of Example 1, Example 2, Comparative Example 3 and Comparative Example 5 were poured into standard flat steel molds with stress inducers, each measuring 800 mm x 800 mm x 100 mm, to complete the vibration compaction and surface smoothing operations.

[0131] The molded specimens, along with the mold, were moved into an environmental control room. The room temperature was set to 30 degrees Celsius and the relative humidity to 40%. A parallel directional airflow with a wind speed of 5 meters per second was applied 300 mm above the surface of the specimens to accelerate the evaporation of moisture from the specimen surface and induce shrinkage cracking.

[0132] From the moment the air source is applied, the surface condition of each specimen is continuously observed using a combination of a high-definition industrial camera system and manual inspection. The time it takes for the first visible crack to appear on the surface of the specimen is recorded and counted as the initial cracking time.

[0133] The experiment was stopped after the crack-inducing environmental conditions had been maintained for 24 hours. Using a graduated reading microscope with 40x magnification, the cracks on the surface of each specimen were fully scanned and measured, and the maximum width of a single crack was recorded.

[0134] The straight-line length of each crack was measured, and the crack width was determined at intervals not exceeding 50 mm along the crack length direction. The arithmetic mean of these measurements was taken as the average width of the crack. The crack area of ​​each crack was calculated based on the average crack width. The total crack area per unit area was calculated by summing the crack areas of all cracks and dividing by the surface area of ​​the specimen. In this test example, the crack resistance level was evaluated based on the total crack area per unit area: not exceeding 20 mm. 2 ·m -2 Classified as Level I, greater than 20mm 2 ·m -2 and no more than 100mm 2 ·m -2 Classified as Level II, greater than 100mm 2 ·m -2 It is classified as Level III.

[0135] The experimental data are shown in Table 4. Each group consisted of at least three parallel plate specimens. The initial cracking time, maximum crack width, and total crack area per unit area in Table 4 are the average values ​​of the test results for the parallel specimens. Table 4: Crack resistance test results of flat plates in the examples and comparative examples Test object Initial cracking time (h) Maximum crack width (mm) <![CDATA[Total crack area per unit area (mm 2 ·m -2 )]]> Crack resistance level evaluation Example 1 12.4 0.08 15.2 Level I Example 2 14.1 0.05 9.7 Level I Comparative Example 3 8.3 0.32 184.6 Level III Comparative Example 5 11.2 0.21 87.3 Level II According to the data in Table 4, under the temperature, humidity, and directional wind speed conditions set in this test example, the initial cracking times for Example 1 and Example 2 were 12.4 h and 14.1 h, respectively; the maximum crack widths were 0.08 mm and 0.05 mm, respectively; and the total cracked area per unit area was 15.2 mm, respectively. 2 ·m -2 and 9.7mm 2 ·m -2The crack resistance level of both samples was determined to be Grade I. The above results indicate that, under the test conditions, Examples 1 and 2 exhibited lower crack widths and crack area per unit area compared to the comparative example, demonstrating that the combination of the multi-scale fiber system and the multi-stage expansion compensation system helps improve the crack resistance of the plate specimens under accelerated water loss conditions.

[0136] The initial cracking time in Example 2 was longer than that in Example 1, and its maximum crack width and total crack area per unit area were both lower than those in Example 1. Considering the relatively high proportion of porous fine aggregate with early expansion sources and water release in the high humidity zone in Example 2, it can be concluded that Example 2 has a more significant early compensation deformation and crack limiting effect in the early water loss and plastic shrinkage stages. This result indicates that a mix design biased towards early crack prevention is beneficial in reducing the degree of early crack development in flat plate specimens.

[0137] Comparative Example 3 had an initial cracking time of 8.3 hours, a maximum crack width of 0.32 mm, and a total cracked area of ​​184.6 mm². 2 ·m -2 The crack resistance level was determined to be Grade III. Compared with Example 1, Comparative Example 3 retained the preparation and addition steps of the microfiber carrier mixture, but in the cumulative fiber dispersion energy stage, short-scale macroscopic polyolefin fibers and long-scale macroscopic polyolefin fibers were simultaneously added to the main mixer, without adopting cascade feeding control based on power feedback. The above results indicate that when multi-scale fibers are mixed in simultaneously, the possibility of local entanglement or secondary trapping between fibers of different scales increases, which may reduce the uniformity of fiber distribution and bridging efficiency in the slurry. Therefore, Comparative Example 3 showed a shortened initial cracking time, increased crack width, and increased total crack area per unit area in the plate initiation cracking test.

[0138] Comparative Example 5 had an initial cracking time of 11.2 hours, a maximum crack width of 0.21 mm, and a total cracked area per unit area of ​​87.3 mm². 2 ·m -2 The crack resistance level was determined to be Grade II. This result indicates that the single calcium sulfoaluminate-based expansion agent system can still provide some volume compensation in the early stages, but its control effect on crack width and crack area per unit area is lower than that of Examples 1 and 2. Because Comparative Example 5 removed the fast-reacting magnesium oxide expansion agent and the slow-reacting magnesium oxide expansion agent, its expansion compensation source is relatively singular, and the compensation effect time window is relatively concentrated. Under the combined effect of continuous surface evaporation and internal self-drying, its limiting effect on crack propagation is relatively insufficient.

[0139] In summary, the results shown in Table 4 indicate that combining multi-scale fiber graded dispersion, cascaded feeding control, and a multi-stage expansion compensation system helps delay the initial cracking time of flat plate specimens and reduces crack width and total crack area per unit area. Specifically, the dispersion state of microfibers and macroscopic polyolefin fibers mainly affects crack bridging and stress dispersion, while the multi-stage expansion compensation system primarily affects volumetric deformation compensation during early and subsequent water loss processes. The combination of these two methods can synergistically improve the cracking performance of flat plates.

[0140] Test Example 5: Experimental Description: This test case is used to evaluate the effect of the phased dynamic distribution of mechanical mixing energy in the mixing process on the flexural strength and bending toughness of hardened concrete specimens. It focuses on verifying the technical feasibility of the synergistic control mechanism of limiting the excessive redispersion of premix and promoting the full unbundling of multi-scale fibers in improving the bending force transmission efficiency and physical toughening of pavement materials.

[0141] Experimental steps: The concrete mixtures prepared in Examples 1, 4, 2, and 4 were used to cast standard small beam specimens with dimensions of 150 mm x 150 mm x 600 mm. Standard vibration was applied during the molding process, and the surfaces were smoothed and then covered with a film for settling.

[0142] After the specimens were left to stand in the mold for 24 hours, they were demolded and then transferred to a standard curing room with a temperature set at 20 degrees Celsius with a fluctuation of 2 degrees Celsius and a relative humidity of not less than 95% for curing, reaching test ages of 28 days and 90 days respectively.

[0143] Extract specimens that have reached the specified age and wipe off surface moisture. Install a three-point bending test loading device on a universal testing machine and adjust the support span to 450 mm. Place the specimen on the support with its side as the tension surface and install a high-precision linear variable displacement sensor at the bottom mid-span of the specimen to record the mid-span deflection during the test.

[0144] Start the testing machine and apply continuous loading in displacement control mode at a rate of 0.1 mm per minute. Record the applied load and mid-span displacement / deflection data in real time via a host computer data acquisition system until macroscopic failure of the specimen occurs or the mid-span deflection reaches the set limit, at which point loading stops.

[0145] Export the raw data of the entire load and displacement test. Calculate the flexural strength at 28 days and 90 days based on the material mechanics calculation formulas, combined with the specimen dimensions and peak load. Calculate the fracture energy of the specimen based on the area integral covered by the load-deflection curve, extract the bearing capacity data corresponding to characteristic deflection nodes, and calculate the flexural toughness index and post-cracking residual tensile strength.

[0146] The experimental data are shown in Table 5. Each group contained no fewer than three parallel beam specimens. The flexural strength, fracture energy, flexural toughness index, and residual tensile strength after cracking in Table 5 are the average values ​​of the test results for the parallel specimens. Table 5: Test results of flexural strength and mechanical toughness of hardened concrete in the examples and comparative examples Test object 28-day flexural strength / MPa 90-day flexural strength / MPa <![CDATA[Fracture energy / N·m -1 > Flexural toughness index Residual tensile strength after cracking / MPa Example 1 6.84 7.61 4652.8 19.4 3.52 Example 4 6.27 6.95 3815.4 14.6 2.81 Comparative Example 2 5.14 5.68 1625.3 6.1 0.94 Comparative Example 4 5.53 6.17 2514.7 9.3 1.58 According to the data in Table 5, the 28-day flexural strength of Example 1 is 6.84 MPa, the 90-day flexural strength is 7.61 MPa, and the fracture energy is 4652.8 N·m. -1 The flexural toughness index was 19.4, and the residual tensile strength after cracking was 3.52 MPa. Compared with Example 4, Comparative Example 2, and Comparative Example 4, Example 1 showed higher levels in all of the above indicators. These results indicate that, under the test conditions, the combined process of late addition of functional premix, segmented control of post-mixing energy, and multi-scale fiber cascade feeding helps improve the flexural performance and post-cracking bearing capacity of the hardened concrete beam specimen.

[0147] Example 1 employs a cascaded feeding method based on power feedback, allowing short-scale and long-scale macroscopic polyolefin fibers to enter the mixing system sequentially at different mixing stages. This process helps reduce the probability of local entanglement or agglomeration during simultaneous mixing of fibers of different scales, thereby enabling the fibers to form a relatively continuous bridging effect in the tension zone. During three-point bending loading, the polypropylene microfibers mainly restrict the propagation of early microcracks, while the macroscopic polyolefin fibers mainly undertake the role of bridging across cracks and dissipating pull-out energy after crack formation. Therefore, Example 1 exhibits higher fracture energy, flexural toughness index, and residual tensile strength after cracking.

[0148] The 28-day flexural strength of Example 4 was 6.27 MPa, the 90-day flexural strength was 6.95 MPa, and the fracture energy was 3815.4 N·m. -1 The flexural toughness index was 14.6, and the residual tensile strength after cracking was 2.81 MPa, both lower than those of Example 1. The main difference between Example 4 and Example 1 lies in the different triggering conditions for adding long-scale macroscopic polyolefin fibers. Example 4 used a higher power fallback trigger threshold and a shorter stabilization time, allowing the long-scale macroscopic polyolefin fibers to enter the mixing system earlier. This result indicates that when long-scale macroscopic polyolefin fibers are added too early, the possibility of local overlap, entanglement, or secondary trapping between fibers of different sizes increases, which may reduce the fiber bridging force transmission efficiency and the energy dissipation capacity after cracking.

[0149] Comparative Example 2 did not prepare a functional premix P; instead, porous fine aggregate L2 with low humidity release and delayed-reaction magnesium oxide expansion agent MgO-B were directly added to the main mixer. Its fracture energy was 1625.3 N·m. -1The flexural toughness index was 6.1, and the residual tensile strength after cracking was 0.94 MPa, which were lower than those in Examples 1 and 4. This result indicates that without establishing a close physical contact relationship and proximity distribution relationship between L2 and MgO-B, the coordination between the mid-to-late stage internal curing water supply and the delayed reaction expansion compensation may be reduced, thus hindering the limitation of shrinkage damage and fiber interface damage in the hardened matrix, ultimately leading to a decrease in flexural toughness-related indices.

[0150] Although Comparative Example 4 prepared a functional premix P, it was the first premix added to the main mixer and subjected to a full cycle of dry and wet mixing with coarse and fine aggregates and cementitious powders. Furthermore, the total post-mixing energy was not divided into premix dispersion energy and fiber dispersion energy. Its fracture energy was 2514.7 N·m. -1 The flexural toughness index was 9.3, and the residual tensile strength after cracking was 1.58 MPa. These results indicate that the pre-preparation of the functional premix itself can provide some improvement; however, if it undergoes prolonged shearing and redispersion during subsequent mixing, it may weaken the pre-formed proximity distribution relationship between L2 and MgO-B. Therefore, the mechanical properties of Comparative Example 4 are better than those of Comparative Example 2 without functional premix, but still lower than those of Example 1, which uses late addition and energy segmentation control.

[0151] In summary, the results shown in Table 5 indicate that the pre-preparation of functional premix P, the delayed addition after the formation of the basic rheology, the staged distribution of post-mixing energy, and the cascade addition control of multi-scale fibers all improve the flexural strength, fracture energy, flexural toughness index, and residual tensile strength after cracking of hardened concrete. Among these, the functional premix mainly affects the mid-to-late stage volume stability and damage control in the fiber-adjacent slurry region, while the cascade addition of multi-scale fibers mainly affects the fiber dispersion state and post-cracking bridging efficiency. The combination of both can improve the flexural toughness of pavement concrete materials.

[0152] The technical features of the above embodiments can be combined in any way (as long as there is no contradiction in the combination of these technical features). For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; these embodiments not explicitly written should also be considered to be within the scope of this specification.

Claims

1. A high-toughness cement concrete pavement material, characterized in that, The road surface material is made of components comprising the following parts by weight: 285-320 parts of silicate cement; 45-60 parts of slag powder; 25-40 parts fly ash; 15-18 parts silica fume; 12-24 parts of calcium sulfoaluminate-based expanding agent; 4-7 parts of fast-reacting magnesium oxide expanding agent; 7-12 parts of delayed-reaction magnesium oxide expanding agent; 600-660 parts of natural fine aggregate; 1000-1080 parts of coarse aggregate; Effective mixing water: 138-150 parts; 2.8-4.0 parts of polycarboxylate superplasticizer; 0.3-0.5 parts of air-entraining agent; 0.6-0.9 parts of polypropylene microfibers; Short-scale macroscopic polyolefin fibers: 1.4-3.0 parts; Long-scale macroscopic polyolefin fibers: 1.6-3.3 parts; 25-45 parts of porous fine aggregate for water release in high humidity areas; 45-70 parts of porous fine aggregate for water release in areas with lower humidity.

2. The high-toughness cement concrete pavement material according to claim 1, characterized in that, The high-humidity zone water-releasing porous fine aggregate has a 24-hour water absorption rate of no less than 21%, and its internal capillary pore size is distributed in the range of 50-200 nm; the high-humidity zone water-releasing porous fine aggregate has a 24-hour water absorption rate of no less than 21%, and its internal capillary pore size is distributed in the range of 50-200 nm; Fine aggregates include both coarse and fine particles; The water absorption rate of the porous fine aggregate in the lower humidity zone is not less than 23% in 24 hours, and its internal capillary pore size is distributed in the range of 10-50 nm.

3. The high-toughness cement concrete pavement material according to claim 1, characterized in that, The pavement material satisfies the following equivalent coefficient relationship: WIC / (0.035Mb+0.447MB) is between 1.05 and 1.35; Wherein, WIC is the total amount of free water carried by all porous fine aggregates; Mb is the total mass of silicate cement, slag powder, fly ash and silica fume in the system; and MB is the total mass of the delayed-reaction magnesium oxide expanding agent.

4. The high-toughness cement concrete pavement material according to claim 1, characterized in that, The polypropylene microfibers are 3-12 mm long and 15-40 μm in diameter; the short-scale macroscopic polyolefin fibers are 25-35 mm long; and the long-scale macroscopic polyolefin fibers are 45-55 mm long, with continuous indentations or rough textures on their surfaces.

5. The high-toughness cement concrete pavement material according to claim 1, characterized in that, The dry mixture of the road surface material includes microfiber carrier mixture and functional premix; The microfiber carrier mixture is formed by physically mixing fine-grained, high-humidity zone water-releasing porous aggregate after water treatment with polypropylene microfibers, and the dry mass ratio of the fine-grained, high-humidity zone water-releasing porous aggregate to polypropylene microfibers is 6:1 to 18:

1. The functional premix is ​​prepared by physically mixing water-treated porous fine aggregate with a portion of the delayed-reaction magnesium oxide expansive agent in a low humidity zone. The dry mass ratio of the water-treated porous fine aggregate with a low humidity zone to the delayed-reaction magnesium oxide expansive agent is 45:4 to 70:

8.

6. A crack-resistant construction method for high-toughness cement concrete pavement material as described in any one of claims 1-5, characterized in that, Includes the following steps: S1: Weigh each raw material component according to the mixing ratio; S2: Soak and pre-wet the porous fine aggregates that release water in high humidity areas and the porous fine aggregates that release water in low humidity areas, and control the surface free water content; S3: Microfiber carrier mixture and functional premix are prepared by using the partially pre-wetted high humidity zone water-releasing porous fine aggregate and the low humidity zone water-releasing porous fine aggregate, respectively; S4: The minimum unit mass mixing energy calibration value is obtained by calibrating the main mixer under no-load and with material operation. S5: Add the base materials, excluding the functional premix, the microfiber carrier mixture, the short-scale macroscopic polyolefin fiber, the long-scale macroscopic polyolefin fiber, and the remaining unmixed delayed-reaction magnesium oxide expanding agent, into the main mixer for dry mixing; then add the first part of the liquid component for wet mixing, monitor the stirring power to show a wet mixing peak and then drop, add the functional premix and accumulate the premix dispersion energy; S6: Alternately add the remaining second part of the liquid component to the microfiber carrier mixture. After the addition is complete, stop the accumulation of premix dispersion energy and accumulate fiber dispersion energy. S7: Based on the drop and stabilization characteristics of the main mixer's operating power as the timing trigger threshold, the short-scale macroscopic polyolefin fiber and the long-scale macroscopic polyolefin fiber are added sequentially in staggered shifts until the total actual post-mixing energy meets the unloading control standard before unloading.

7. The crack-resistant construction method for high-toughness cement concrete pavement material according to claim 6, characterized in that, In step S2, the porous fine aggregate is pre-wetted in water at 10-30℃ for 12-24 hours. After draining, the free water content on the surface of the coarse-grained porous fine aggregate in the high-humidity zone is controlled to be no more than 0.3% of the dry weight, the free water content on the surface of the fine-grained porous fine aggregate in the high-humidity zone is no more than 0.4% of the dry weight, and the free water content on the surface of the porous fine aggregate in the low-humidity zone is no more than 0.8% of the dry weight. In step S3, the preparation method of the functional premix is ​​as follows: the pre-wetted and drained low-humidity zone water-releasing porous fine aggregate and part of the delayed-reaction magnesium oxide expansion agent are physically mixed in a mixer for 30-60s; the preparation method of the microfiber carrier mixture is as follows: the pre-wetted and drained fine-grained high-humidity zone water-releasing porous fine aggregate is first put into the mixing hopper, and all the polypropylene microfibers are evenly sprinkled in within 15-30s, and the mixture is continued for 20-40s.

8. The crack-resistant construction method for high-toughness cement concrete pavement material according to claim 6, characterized in that, In step S5, the first liquid component accounts for 75% of the total mass of the liquid component, and the second liquid component accounts for 25% of the total mass of the liquid component; in step S6, the overlap time of the alternating addition of the second liquid component and the microfiber carrier mixture is controlled between 50% and 100%.

9. The crack-resistant construction method for high-toughness cement concrete pavement material according to claim 6, characterized in that, In step S7, the control logic for staggered peak feeding is as follows: Short-scale macroscopic polyolefin fibers were sprinkled in within 15-25 seconds, and the stable power before addition and the power peak formed after addition were recorded. Continuously monitor the operating power of the main mixer. When the power drops to the sum of the stable power and 30%-60% of the maximum power increment, and remains so for 3-8 seconds, add long-scale macroscopic polyolefin fibers within 20-35 seconds and continue mixing until discharge.

10. The crack-resistant construction method for high-toughness cement concrete pavement material according to claim 6, characterized in that, In step S7, the total actual post-mixing energy during unloading is 1.00-1.20 times the minimum unit mass post-mixing energy calibration value, and the system energy distribution satisfies that the premix dispersion energy accounts for 30%-45% of the total actual post-mixing energy, and the fiber dispersion energy accounts for 55%-70% of the total actual post-mixing energy.

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