Method for stabilizing graded broken stone material by using calcium carbide fly ash and application thereof

Abstract

The invention relates to a method for stabilizing a graded broken stone material by using calcium carbide fly ash and application of the method. The method is suitable for base construction of expressways and heavy traffic roads. The compactness and strength of the material are improved by optimizing the ratio of the calcium carbide fly ash to the graded broken stone, adding an electrochemical exciting agent, treating with a weakly alkaline solution and performing CO2 mineralization reaction; and the vibration compaction technology and the wet curing technology are combined, so that the crack resistance and durability of the material are enhanced. The invention overcomes the problem of insufficient material performance in a complex environment in the prior art, realizes comprehensive improvement of material strength, durability and crack control, adapts to the condition requirements of construction area temperature of-10 DEG C to 40 DEG C and humidity of 50%-95%, and adopts the technical means of low-temperature wet maintenance, antifreezing agent addition and the like to enhance the adaptability of the material in an extreme environment, so that the construction cost is reduced. And therefore, the construction method is widely applicable to base construction of expressways and heavy traffic roads, and meets the long-term use requirements under complex weather conditions.

Description

Technical Field

[0001] The present invention relates to the field of road construction materials, and specifically to a method for stabilizing graded crushed stone materials using carbide slag fly ash and its application. Background Art

[0002] During the process of road construction and maintenance, traditional graded crushed stone materials are prone to deformation and damage under heavy traffic and adverse weather conditions due to lack of sufficient stability, which affects the service life of the road. In recent years, the technology of industrial waste reuse has become a popular research direction, and carbide slag fly ash has been widely concerned as a potential modified additive. At present, the application of carbide slag fly ash in cement concrete has been relatively mature, but its effective utilization rate in graded crushed stone materials still needs to be improved.

[0003] The main problems faced by the existing technology: The main problem of traditional graded crushed stone materials is poor stability, especially prone to water stability and dry shrinkage cracks in hot and humid environments, resulting in accelerated damage to the road structure.

[0004] Existing solutions and their limitations: Currently, in order to enhance the stability of graded crushed stone, cement, lime or other cementitious materials are usually added. However, this method not only increases the construction cost but also may cause environmental problems such as excessive carbon dioxide emissions. In addition, traditional reinforcement methods often ignore the compatibility between materials and the changes in the microstructure, thus reducing the overall performance of the materials. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the present invention provides a method for stabilizing graded crushed stone materials using carbide slag fly ash and its application, which solves the problem that the existing technology ignores the compatibility between materials and the changes in the microstructure, thus reducing the overall performance of the materials.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A method for stabilizing graded crushed stone materials using carbide slag fly ash, comprising the following steps: S1. Mix carbide slag fly ash and graded crushed stone in a mass ratio of 5% - 8% and 85% - 90%; Carbide slag fly ash, as an industrial by-product, is rich in calcium oxide (CaO), silicate and aluminate, and can generate cementitious products (C-S-H gel and ettringite) through hydration reaction in subsequent steps, providing the strength and stability of the materials. Graded crushed stone serves as the skeleton of the material, providing overall mechanical support. Carbide slag fly ash and crushed stone can ensure that the hydration reaction products are evenly distributed on the particle surface, improving the bonding force between particles, thereby enhancing the overall structural strength.

[0007] S2. Add an electrochemical activator to the mixture. The electrochemical activator includes sodium sulfate and potassium chloride, and the total dosage is 1% - 2% of the mass of the mixture. Sodium sulfate and potassium chloride will ionize to generate Na + , K + , SO 4 2- active ions under the action of the subsequent weak alkaline environment and moisture. On the one hand, the active ions can accelerate the dissolution of active calcium oxide, silicate and aluminate in carbide slag fly ash, and enhance the initial hydration reaction rate; on the other hand, the generated calcium sulfoaluminate and other hydration products can significantly improve the early strength of the mixture. In addition, potassium ions and sodium ions can optimize the ion migration rate of the hydration reaction, and improve the distribution uniformity of hydration products and the compactness of the microstructure.

[0008] S3. Add moisture to the mixture. The proportion of the moisture is 8% - 12% of the mass of the mixture. Moisture is the medium for the hydration reaction. Its main function is to activate calcium oxide, silicate and aluminate in carbide slag fly ash, and react with water to generate C-S-H gel, ettringite and calcium hydroxide. The hydration products form a cementing effect between particles, significantly enhancing the strength and stability of the material. At the same time, appropriate moisture helps to maintain the workability of the mixture, preventing insufficient reaction due to too little moisture or reducing the early strength of the material due to too much moisture.

[0009] S4. Apply an electric field to the mixture under a weak alkaline environment. The voltage range is 5 - 15 volts, and the treatment time is 20 - 30 minutes. The application of the electric field accelerates the ion migration rate in the mixture, enhancing the reaction kinetic efficiency between the electrochemical activator and the active components of carbide slag fly ash. The weak alkaline environment further promotes the dissolution of calcium oxide, enabling more active ions to participate in the hydration reaction to generate stable compounds such as C-S-H gel and ettringite. The electric field treatment can also improve the microstructure distribution of the mixture, forming a more compact hydration product network structure, significantly enhancing the early strength of the material.

[0010] S5. Pass gaseous carbon dioxide into the mixture after electric field treatment. The carbon dioxide concentration is 5% - 10%, and the treatment time is 10 - 15 minutes. After passing in carbon dioxide, it undergoes a chemical reaction with calcium hydroxide generated during the hydration process to form calcium carbonate (CaCO 3 ) crystals. The reaction is as follows: Ca(OH) 2 +CO 2 →CaCO 3 +H 2 O The generated calcium carbonate crystals can fill the pore structure of the mixture and improve the compactness of the material. At the same time, the formation of calcium carbonate crystals can optimize the anti-cracking performance of the material and inhibit the expansion of dry shrinkage cracks. In addition, carbon dioxide treatment can further enhance the water stability of the material, making it have better durability in a humid environment.

[0011] S6. Compact and form the treated mixture, and the compaction density reaches more than 95% of the maximum theoretical density; through mechanical vibration compaction, the pores in the mixture can be effectively removed, making it reach a highly dense structural state. During the compaction process, the mutual interlocking and combination between particles further enhance the mechanical properties of the material. In addition, after compaction and forming, the hydration reaction products further fill the pores in the compacted state, significantly improving the overall strength and stability of the material.

[0012] S7. Conduct wet curing on the compacted material for no less than 7 days, and control the humidity at 85% - 95%. Wet curing can provide sufficient water for the subsequent hydration reaction, promote the generation and uniform distribution of hydration products, thereby further improving the strength and durability of the material. Controlling the humidity within the range of 85% - 95% can effectively prevent dry shrinkage cracks caused by excessive water loss on the surface of the material. In addition, wet curing can also maintain the microstructural stability of the material, further enhancing the anti-cracking and water stability.

[0013] Preferably, the particle size of the graded crushed stone is less than 4.75 mm, accounting for 15% - 25% of the total mass of the crushed stone, and the part with a particle size less than 0.075 mm does not exceed 10% of the total mass of the fine particles. In material design, the reasonable particle size distribution of graded crushed stone is a key parameter to ensure the strength, compactness, and water stability of the mixture. Specifically, the fine particles with a particle size less than 4.75 mm can improve the filling effect and compactness of the mixture and optimize the overall skeleton structure. And the very fine particles (i.e., powder) with a particle size less than 0.075 mm play an important role in the hydration reaction and the later strength development of the material, but the content control is very crucial and needs to be limited to less than 10% of the total mass of the fine particles; The coarse particles and fine particles together constitute the skeleton structure of the material. The fine particles (with a particle size less than 4.75 mm) enhance the compactness of the mixture by filling the voids between the coarse particles, reducing the porosity, and thus improving the mechanical properties and water stability of the material. At the same time, a reasonable content of fine particles makes the interlocking effect between particles more obvious, contributing to improving the shear strength and compressive strength; The very fine particles with a particle size less than 0.075 mm belong to extremely fine powder, and their functions are mainly reflected in two aspects: Lubricating effect: The very fine particles are distributed between the coarse and fine particles during the mixing process, playing a role similar to a "lubricant", improving the workability of the material, reducing the mixing resistance, and enhancing the constructability of the mixture; Reaction promotion: Some fine particles (active particles in stone powder or calcium carbide fly ash) can participate in chemical reactions during the hydration reaction to form calcium silicate hydrate (C-S-H) and other cementitious products, further enhancing the bonding and denseness of the material.

[0014] Preferably, the average particle size of the calcium carbide fly ash is 50 - 70 μm, the specific surface area of the powder is 4000 - 6000 cm 2 / g, the free calcium oxide content is 15% - 25%, and the silicate content is 40% - 55%. The design of these characteristic parameters of the calcium carbide fly ash is to achieve the optimized performance of the material, ensure its effective activity in the mixture, improve the early strength and long-term durability of the material, and avoid problems such as cracks or uneven strength during use; The particle size of the calcium carbide fly ash particles is in the range of 50 - 70 μm, which can not only provide a sufficient specific surface area to promote the hydration reaction, but also avoid the premature reaction failure or agglomeration of the material caused by too small particle size; The specific surface area of the calcium carbide fly ash is 4000 - 6000 cm 2 / g. The relatively high specific surface area provides more active reaction sites, enabling active components such as calcium oxide and silicate to quickly react with water to form products such as C-S-H gel, thus significantly improving the early strength and later denseness of the material; If the specific surface area is too high (>6000 cm 2 / g), it may cause the material to adsorb too much water and the hydration reaction is incomplete; while if the specific surface area is too low (<4000 cm 2 / g), its activity will be weakened and the strength growth rate of the material will be reduced. Therefore, a specific surface area of 4000 - 6000 cm 2 / g is the optimal range considering comprehensive activity, strength, and construction performance; The role of calcium oxide in the hydration reaction: Free calcium oxide (CaO) is one of the main active components of calcium carbide fly ash and quickly reacts with water to form calcium hydroxide (Ca(OH) 2 ) during the hydration process: CaO + H 2 O → Ca(OH) 2 The generated calcium hydroxide can further react with the silicate (SiO 2 ) in the fly ash to form the cementitious product C-S-H gel: Ca(OH) 2 + SiO 2 + H 2 O → C-S-H gel C-S-H gel is the key substance determining the strength and compactness of the mixture. By designing the content of free calcium oxide to be 15% - 25%, sufficient Ca(OH) 2 generation rate can be ensured, thus promoting the hydration reaction of silicate; Control of free calcium oxide content: Too low content (<15%): The hydration reaction rate decreases, the early strength is insufficient, which may prolong the curing time of the material and affect the construction progress; Too high content (>25%): It may cause a large amount of Ca(OH) to be generated in the initial stage of hydration 2 , resulting in crystal supersaturation and triggering microcrack problems, thereby reducing the long-term durability; Controlling the free calcium oxide content within the range of 15% - 25% can not only ensure the activity of the material but also avoid the generation of cracks or uneven strength.

[0015] Control of silicate content: Too low content (<40%): Insufficient C-S-H gel is generated, the hydration reaction efficiency decreases, resulting in slow strength growth of the material.

[0016] Too high content (>55%): It may introduce more inert silicate particles, which are difficult to react with Ca(OH) 2 , increasing the porosity of the material, weakening the compactness and affecting the mechanical properties.

[0017] When the silicate content is within the range of 40% - 55%, the balance between the hydration reaction efficiency and the material compactness can be achieved, thus meeting the performance requirements of the road base material.

[0018] Preferably, the weak alkaline environment is prepared by dissolving calcium hydroxide, the solution concentration is 0.5% - 1.5%, the temperature of the solution is controlled at 15°C - 30°C. The weak alkaline environment is prepared by dissolving calcium hydroxide in water, the solution concentration is preferably 0.5% - 1.5%, and the temperature of the solution is controlled at 15°C - 30°C. During the solution preparation process, calcium hydroxide is gradually added in solid form to the stirred deionized water to ensure complete dissolution and reach the designed concentration. The temperature of the solution is controlled at 15°C - 30°C by a constant temperature device to avoid the influence of temperature fluctuation on the reaction efficiency of the material; Calcium hydroxide (Ca(OH) 2 ), as the main component of the weak alkaline environment, dissociates hydroxide ions (OH - ) in the aqueous solution, and its chemical reaction formula is: OH -Ions can increase the pH value of the solution to the weakly alkaline range (pH 8 - 10), and this environmental condition can significantly promote the dissolution reaction of the active components in carbide slag fly ash. The silicate and aluminate components dissociate under the action of OH - and participate in further hydration reactions to form gel products (C-S-H gel and ettringite), thereby improving the mechanical properties of the material.

[0019] Selection of concentration range: When the solution concentration is lower than 0.5%, the supply of OH - is insufficient, and the active components of carbide slag fly ash cannot be fully activated, resulting in a decrease in reaction efficiency and slow strength growth of the material; When the solution concentration is higher than 1.5%, it causes too fast local reaction, generating excessive Ca(OH) 2 crystals, reducing the uniformity of the hydration products, and at the same time may induce microcrack problems. Therefore, controlling the calcium hydroxide concentration between 0.5% and 1.5% can ensure a moderate OH - concentration, effectively promoting the hydration reaction and ensuring the uniformity of the products.

[0020] Synergistic effect of weakly alkaline environment on electrochemical activation: The combination of a weakly alkaline environment and electrochemical activation can significantly improve the reaction activity of the material. Under the action of an external electric field, electrochemical activation enhances the diffusion and reaction efficiency of Ca 2+ and SiO 4 4- in carbide slag fly ash through ion migration, while the weakly alkaline environment further accelerates the reaction rate of these ions by providing OH - .

[0021] In addition, the Ca(OH) - formed by the reaction of OH 2+ with Ca 2 can serve as the basic substance for subsequent CO 2 mineralization reaction to form CaCO 3 crystals to fill the pores, further improving the density and durability of the material.

[0022] Preferably, the mass ratio of sodium sulfate to potassium chloride in the electrochemical activator is 1:1 to 3:2. The electrochemical activator is added in the form of solid powder and dissolves after sufficient contact with the moisture in the mixture to activate the active components of carbide slag fly ash, accelerate the hydration reaction, and improve the early strength and water stability of the material.

[0023] Sodium sulfate and potassium chloride in the electrochemical activator respectively provide SiO 4 2- , Na + and K +Equivalent active ions. The introduction of these ions significantly enhances the activity of carbide slag fly ash: SiO 4 2- Function of ions: SiO 4 2- Ions react with aluminates in carbide slag fly ash to form ettringite. This reaction not only improves the early strength of the material but also optimizes the microstructure of the mixture, fills pores, and reduces the generation of microcracks. The reaction process is as follows: 3Ca 2+ + 3SO 4 2- + 6AlO 2 - + 30H 2 O → 3CaO·Al 2 O 3 ·3CaSO 4 ·32H 2 O The formation of ettringite can rapidly improve the volume stability and crack resistance of the material.

[0024] Na + and K + Function of ions: Na + and K + As electrolyte ions, Na and K ions can reduce the ion migration resistance in the solution, increase the diffusion rate of active ions in the mixture, promote the reaction rate of silicates, accelerate the formation of C-S-H gel, and enhance the cementing performance of the material.

[0025] When the mass ratio is 1:1: SiO 4 2- and Na + 、K + have relatively balanced concentrations, which can effectively stimulate the calcium oxide, silicate, and aluminate components in carbide slag fly ash to form uniformly distributed hydration products. However, due to the relatively low relative concentration of SiO 4 2- , the formation rate of ettringite is relatively slow, and the early strength growth of the material is slightly insufficient.

[0026] When the mass ratio is 3:2: Increasing the proportion of SiO 4 2- can accelerate the formation of ettringite, significantly improve the early strength of the material, and at the same time optimize the pore structure, increase the density and water stability of the material. However, too high a proportion of SiO 4 2-The ratio results in excessive formation of ettringite in the later stage of the material, inducing volume expansion and affecting long-term stability. Therefore, a mass ratio of 3:2 is the balance point for ettringite formation and volume stability.

[0027] Preferably, the compaction speed of the compaction molding is 2 - 4 m / min, the single-layer compaction thickness is 15 - 20 cm, the vibration frequency is 30 - 50 Hz, and the amplitude is controlled at 2 - 5 mm. By reasonably controlling the compaction parameters, the density and overall mechanical properties of the mixture can be effectively improved, its crack resistance and durability can be optimized, and at the same time, the construction efficiency can be ensured to be improved and the construction quality can be consistent.

[0028] Under the control of the above compaction parameters, a dense skeleton structure is formed in the vibration compaction process of the mixture: Formation of the coarse-grained skeleton: The vibration causes the coarse grains to rearrange under the external force, enhancing the filling effect and gradually forming a skeleton structure with the main bearing capacity.

[0029] Filling effect of fine grains: The fine grains are squeezed into the pores of the coarse grains under the combined action of the vibration frequency and amplitude, thereby improving the density and uniformity of the material.

[0030] Interlocking and locking: During the vibration compaction process, the interlocking and locking effect between particles is enhanced, forming an integral structure with high strength and high stability.

[0031] Preferably, in the step of introducing carbon dioxide, the carbon dioxide gas is sprayed through a uniform distribution device arranged at the top of the reaction vessel, and the gas flow rate of carbon dioxide is controlled at 0.5 - 1.5 m 3 / min. The distribution method and flow rate of carbon dioxide ensure that the gas uniformly contacts the surface of the mixture and penetrates into the material interior, thereby realizing an efficient mineralization reaction, optimizing the microstructure of the material, and enhancing its strength, density and durability.

[0032] After the carbon dioxide gas is sprayed onto the surface of the mixture through the uniform distribution device, it undergoes a mineralization reaction with calcium hydroxide (Ca(OH) 2 ) generated during the hydration process to produce calcium carbonate (CaCO 3 ), and its reaction formula is as follows: Ca(OH) 2 +CO 2 →CaCO 3 +H 2 O The generated calcium carbonate can fill the micro pores of the mixture, optimize the microstructure of the material, and improve its density and crack resistance. The formation of calcium carbonate can also further enhance the water resistance stability and compressive strength of the material.

[0033] By uniformly spraying carbon dioxide gas on the surface of the mixture and controlling the gas flow rate at 0.5 - 1.5 m 3 / min, the comprehensive penetration of carbon dioxide and efficient mineralization reaction can be achieved, generating uniformly distributed calcium carbonate crystals, and improving the compactness, crack resistance and durability of the material.

[0034] Preferably, during the wet curing process, water is sprayed no less than 2 times a day, and the amount of water sprayed each time is 0.5% - 1% of the surface quality of the mixture.

[0035] Supporting effect of wet curing on hydration reaction: The active components (calcium oxide, silicate, aluminate) of calcium carbide fly ash in the mixture can continuously react with water to generate hydration products, C-S-H gel and ettringite under wet curing conditions. Spraying water regularly can continuously provide the water required for the hydration reaction, avoiding the reaction from stopping or being insufficient due to lack of water, thus ensuring the normal development of the material strength; Water evaporation and surface water loss risk: In the early stage after compaction and forming, the surface layer of the material undergoes rapid water evaporation due to contact with air, resulting in a surface shrinkage rate much higher than that of the interior, forming dry shrinkage cracks. By spraying water regularly, the surface can be maintained wet, reducing the shrinkage stress difference between the surface layer and the interior, thus effectively inhibiting the generation of cracks.

[0036] Preferably, an antifreeze is added during the wet curing process. The antifreeze is calcium chloride or calcium formate, and its dosage is 0.5% - 1% of the total mass of the mixture. In a cold environment, the temperature of wet curing is controlled at 0°C - 5°C. The main function of the antifreeze is to lower the freezing point of water in the mixture, maintain the liquid state of water in a low-temperature environment, prevent volume expansion caused by water freezing, and promote the continuous progress of the hydration reaction.

[0037] 1. Calcium chloride (CaCl 2 ) dissociates into Ca 2+ and Cl - after dissolving in water, lowering the freezing point of water and at the same time increasing the ion concentration of the solution, improving the kinetic efficiency of the hydration reaction: Ca(OH) 2 +CaCl 2 →CaCl 2 ·Ca(OH) 2 The generated calcium oxychloride can further promote the formation of C-S-H gel and enhance the early strength of the material.

[0038] 2. Calcium formate (Ca(HCOO) 2 ) dissociates in water to produce formate ions (HCOO -) It can not only lower the freezing point, but also act as a catalyst for the hydration reaction, accelerating the reaction rate of silicate and aluminate and generating more cementitious products.

[0039] In a cold environment, freeze-thaw cycles cause serious damage to the strength and durability of materials. The addition of antifreeze and temperature control in wet curing can significantly enhance the freeze-thaw resistance of materials: Pore filling effect: The C-S-H gel and ettringite generated by the promotion of the hydration reaction by the antifreeze gradually fill the pores of the material, reducing the porosity and making the material denser, thus reducing the sensitivity to freeze-thaw damage.

[0040] Crack inhibition effect: The dense structure and stable hydration reaction of the material effectively inhibit the expansion of microcracks. Even after experiencing freeze-thaw cycles, the risk of crack expansion is significantly reduced.

[0041] Enhanced volume stability: The low freezing point characteristic of the antifreeze reduces the expansion pressure generated by the freezing of internal moisture in the material, thus protecting the volume stability of the material.

[0042] Application of the calcium carbide fly ash stabilized graded crushed stone material prepared based on the above method in road base construction. The material is suitable for the base construction of expressways and heavy traffic roads, and the environmental temperature range of the construction area is from -10°C to 40°C, and the humidity range is from 50% to 95%.

[0043] Low temperature environmental adaptability: Under the low temperature conditions of -10°C to 0°C, the material maintains the liquid state of moisture through the action of the antifreeze, supports the continuous progress of the hydration reaction, and avoids volume expansion and crack expansion caused by water freezing. At the same time, the optimized pore structure (filled with C-S-H gel and ettringite) provides good volume stability, thus enhancing the freeze-thaw resistance of the material.

[0044] High temperature environmental adaptability: Under the high temperature conditions of 30°C to 40°C, the designed microstructure and uniform distribution of hydration products of the material ensure crack resistance and volume stability. The C-S-H gel network structure enhances the bonding force between particles and effectively resists the drying shrinkage and cracking risk caused by high temperature.

[0045] High load adaptability (expressway and heavy traffic conditions): Skeleton support effect: The graded crushed stone in the material provides a strength support skeleton. The coarse particles form the main bearing structure through the interlocking effect, and the fine particles fill the voids between the coarse particles, significantly improving the overall strength of the material.

[0046] Microstructure strengthening: The C-S-H gel and ettringite generated by the hydration reaction of calcium carbide fly ash, together with the calcium carbonate generated by carbon dioxide mineralization, act together to form a dense particle-matrix interface, improving the compressive strength and durability of the material.

[0047] Anti-fatigue performance: Under the dynamic load of long-term heavy traffic, the dense microstructure of the material can effectively disperse stress, reduce the initiation and propagation of microcracks, and improve the fatigue life.

[0048] The present invention provides a method for stabilizing graded crushed stone materials using carbide slag fly ash and its application. It has the following beneficial effects: 1. The present invention adopts a technical scheme combining antifreeze and low-temperature wet curing. In a cold environment (-10°C to 5°C), by adding calcium chloride or calcium formate, the freezing point of the moisture in the mixture is reduced, and the continuity of the hydration reaction is maintained. The products generated by mineralization treatment and hydration effectively fill the pores, enhancing the freeze-thaw resistance of the material. Compared with the prior art in which the reaction rate of wet curing is low at low temperatures and the early strength of the material is insufficient, the problems of crack control and freeze-thaw damage in a low-temperature environment are solved.

[0049] 2. The present invention optimizes the hydration reaction rate and mineralization efficiency by introducing a synergistic treatment method of electrochemical excitation and CO 2 mineralization reaction, generating uniformly distributed C-S-H gels and calcium carbonate crystals. The internal structure of the material is denser, and the crack propagation is effectively inhibited. Compared with the prior art in which the hydration reaction process is highly dependent on the environment, the present invention breaks through the problem of slow strength growth in a complex environment and significantly improves the early strength and long-term durability of the material.

[0050] 3. The present invention uses a graded crushed stone with a reasonable ratio and a fine particle filling technology, combined with precise control of speed, thickness, vibration frequency, and amplitude during the compaction molding process, to form a high-density material skeleton structure. The interlocking effect between particles is significantly enhanced, and the mechanical properties are significantly improved. Compared with the problems of extensive control in traditional compaction processes and uneven density of material layers, the present invention solves the problems of large settlement deformation and insufficient bearing capacity of the material under load, and is particularly suitable for highways and heavy traffic conditions.

[0051] 4. The present invention proposes a synergistic method of wet curing and mineralization based on environmental adaptability design. By adjusting the water spraying amount and gas flow rate, the performance stability of the material in a hot and humid or dry environment is achieved. Under high humidity conditions, calcium carbonate crystals are uniformly generated, effectively enhancing the water erosion resistance; under low humidity conditions, the surface protection effect of the hydration products reduces the drying shrinkage effect. Compared with the prior art in which the strength decreases and cracks increase easily in extreme hot and humid or dry environments, the present invention ensures the comprehensive performance advantages of the material and has stronger applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the preparation process of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0053] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0054] Embodiment 1: Construction application in low-temperature environment: 1. Material preparation: Calcium carbide fly ash and graded crushed stone are mixed in a ratio of 5% - 8% and 85% - 90%. Control the particle size of the crushed stone to be 4.75 mm - 26.5 mm, and the fine particles account for 20% of the total mass of the crushed stone. The particle size of calcium carbide fly ash is 50 - 70 μm, and the specific surface area is 4000 - 6000 cm 2 / g. Add calcium chloride as an antifreeze agent, and its dosage is 1% of the total mass of the mixture.

[0055] 2. Mixing: Evenly sprinkle the electrochemical activator (sodium sulfate and potassium chloride, mass ratio 1:1) in the form of solid powder into the mixture, and the dosage is 1.5% of the total mass of the mixture. Gradually add water in a proportion of 10%, and continuously stir for 5 minutes to ensure uniform distribution.

[0056] 3. Electrochemical activation: Place the mixture in a weakly alkaline environment. The solution is prepared by dissolving calcium hydroxide, and the concentration is 1%. Apply an electric field with a voltage of 10 volts and a treatment time of 25 minutes. Keep the solution temperature at 15°C during the treatment process.

[0057] 4. Compaction and shaping: Lay the mixture layer by layer, with a single-layer thickness of 15 cm. Use a compaction device with a vibration frequency of 40 Hz and an amplitude of 3 mm for compaction, and the compaction speed is 3 m / min to ensure that the compactness reaches more than 95% of the maximum theoretical density.

[0058] 5. Low-temperature wet curing: In an environment with a temperature of -5°C, carry out wet curing for 7 days and cover with a heat-insulating layer. Sprinkle water no less than 2 times a day, and the spraying amount each time is 1% of the surface mass. Prevent cracks from forming on the surface layer due to drying or low-temperature freezing.

[0059] Embodiment 2: Construction application in hot and humid environment: 1. Material preparation: The ratio of calcium carbide fly ash to graded crushed stone is 6% and 88%. The content of fine particles is controlled at 15%, and the particles with a particle size less than 0.075 mm account for 8% of the total mass of the fine particles. The calcium oxide content of calcium carbide fly ash is 22%, and the silicate content is 52%. Calcium formate is added as an auxiliary agent for waterproofing and moisture-proofing, and the dosage is 0.5%.

[0060] 2. Mixing: Sodium sulfate and potassium chloride (mass ratio 2:1) are incorporated as an electrochemical activator, and the dosage is 1% of the total mass. Water is gradually sprayed, and the water content is adjusted to 8%, and continuous stirring is carried out for 7 minutes to ensure that the mixture is moist and uniform.

[0061] 3. Electrochemical activation and mineralization treatment: An electric field is applied in a calcium hydroxide solution with a pH value of 9, the voltage is 12 volts, and the treatment time is 20 minutes. After the electrochemical treatment, carbon dioxide is sprayed through a uniform distribution device, the gas flow rate is 1.2 m 3 / min, and the spraying time is 10 minutes to promote the formation of calcium carbonate inside the material.

[0062] 4. Compaction and shaping: The material is laid in layers, and the thickness of each layer is 20 cm. The compaction equipment is set with a vibration frequency of 50 Hz, an amplitude of 4 mm, and a compaction speed of 2.5 m / min to ensure that the compactness of the material reaches 96%.

[0063] 5. Wet curing: Cure for 7 days in an environment with a humidity of 90% and a temperature of 35°C. Sprinkle water 3 times a day, and the spraying amount each time is 0.8% of the surface mass. Ensure that there is no water accumulation in the material but it is always moist in a high-humidity environment.

[0064] Example 3: Construction of the base course for heavy-duty traffic roads: 1. Material preparation: The dosage of calcium carbide fly ash is 7%, and graded crushed stone accounts for 85% of the total mass. The proportion of fine particles is 18%, and the particles with a particle size less than 0.075 mm account for 10%. Calcium chloride is selected as the antifreeze, and the dosage is 0.8%. The electrochemical activator is sodium sulfate and potassium chloride, with a mass ratio of 3:2, and the total dosage is 1% of the mass of the mixture.

[0065] 2. Mixing: Add the antifreeze and electrochemical activator to the mixture, and gradually spray water until the water content reaches 10.5%. Control the stirring time at 8 minutes to ensure uniform particle distribution and avoid local agglomeration.

[0066] 3. Electrochemical activation and compaction and shaping: Apply an electric field in a weakly alkaline solution (0.8% calcium hydroxide solution) with a voltage of 15 volts and a treatment time of 30 minutes. After treatment, layer by layer compaction is carried out, with each layer having a thickness of 18 cm, a vibration frequency of 35 Hz, an amplitude controlled at 3 mm, and a compaction speed of 3.5 m / min.

[0067] 4. Wet curing and crack control: During wet curing, water is sprayed no less than 2 times a day, and the spraying amount each time is 0.7% of the surface mass. The curing period is 7 days, the curing environment temperature is 20 °C, and the humidity is 50%. Detection of the crack distribution of the material after curing shows no obvious early cracks and uniform strength.

[0068] Example 4: Construction in cold environment under heavy traffic: 1. Material preparation: The ratio of carbide fly ash to graded crushed stone is 5.5% and 87%, and the particle size distribution of the crushed stone is controlled within 4.75 mm - 25 mm. The proportion of fine particles is 16%, the antifreeze is calcium formate, and the dosage is 1%.

[0069] 2. Mixing and compaction molding: In the electrochemical activator, the mass ratio of sodium sulfate to potassium chloride is 1:1, and the total dosage is 1.2%. Water is gradually sprayed, and the water content is controlled at 8.5%, with a stirring time of 6 minutes. In the molding stage, layered paving is adopted, with a single layer thickness of 15 cm, a vibration frequency of 40 Hz, an amplitude of 5 mm, and a compaction speed of 3 m / min.

[0070] 3. Electrochemical activation and wet curing: Carry out electrochemical activation at 0 °C, apply a voltage of 10 volts, and treat for 25 minutes. Cover with a waterproof film for wet curing, keep the temperature at 0 °C to 3 °C, and spray water no less than 2 times a day, with each spraying being 0.6%.

[0071] Example 5: Comprehensive application in highway construction: 1. Material preparation and mixing: The dosage of carbide fly ash is 8%, and the crushed stone accounts for 87%. The antifreeze is calcium chloride, and the dosage is 0.7%. Sodium sulfate and potassium chloride are mixed in a ratio of 2:1, and the total dosage is 1.5%. The water in the mixture is controlled at 10%, and stir for 7 minutes.

[0072] 2. Electrochemical activation and mineralization treatment: Apply an electric field in a weakly alkaline solution with a pH value of 9, with a voltage of 12 volts and a treatment time of 20 minutes. Subsequently, spray CO 2 gas, control the flow rate at 1.5 m 3 / min, spray for 12 minutes to generate calcium carbonate crystals and optimize the material structure.

[0073] 3. Compaction and curing: The single-layer thickness is controlled at 20 cm, the vibration frequency is 50 Hz, the amplitude is 4 mm, and the compaction speed is 2.8 m / min. During wet curing, water is sprayed 3 times a day, each time at 0.8%, and the curing period is 7 days.

[0074] Comparative Example 1 (corresponding to Example 1, construction comparison under low-temperature environment): 1. Material preparation: The proportions of calcium carbide fly ash and graded crushed stone are the same, 7% and 87% respectively. However, the dosage of the antifreeze is adjusted to 0.3%, which is lower than 1% in Example 1. The other parameters remain unchanged.

[0075] 2. Mixing: During mixing, no electrochemical activator is added, and the materials are only stirred in the ordinary way, gradually adding water to 10%, and the stirring time is 4 minutes.

[0076] 3. Omission of electrochemical activation: No electric field treatment is applied, and the mixture is only left standing for 10 minutes and then directly enters the forming step.

[0077] 4. Compaction and forming: The single-layer thickness is controlled at 20 cm, the vibration frequency is adjusted to 25 Hz (lower than 40 Hz in Example 1), the amplitude is 3 mm, and the compaction speed is increased to 4.5 m / min.

[0078] 5. Low-temperature wet curing: The temperature control during wet curing is not precise, about -5°C to -10°C, the number of times of spraying water is reduced to 1 time a day, and the spraying amount each time is about 0.3%. The heat preservation film is not covered during the curing period.

[0079] Comparative Example 2 (corresponding to Example 2, construction comparison under hot and humid environment) 1. Material preparation: The proportions of calcium carbide fly ash and crushed stone are the same as in Example 2, but no calcium formate is added as an auxiliary agent. The proportion of fine particles remains unchanged.

[0080] 2. Mixing: The total dosage of the incorporated electrochemical activator is reduced to 0.5%, the proportion of sodium sulfate and potassium chloride is adjusted to 4:1, and the stirring time is reduced to 3 minutes.

[0081] 3. Electrochemical activation and mineralization treatment: During electrochemical activation, the concentration of the weak alkaline solution is reduced to 0.3%, the voltage is 6 volts, and the treatment time is shortened to 10 minutes. During mineralization treatment, the carbon dioxide gas flow rate is increased to 2.5 m 3 / min, and the spraying time is 5 minutes.

[0082] 4. Compaction and forming: The single-layer thickness is adjusted to 25 cm, the vibration frequency of the compaction equipment is reduced to 20 Hz, the amplitude is controlled at 2 mm, and the compaction speed is increased to 5 m / min.

[0083] 5. Wet curing: During wet curing, the number of times of spraying water is reduced to 1 time / day, and the spraying amount is 0.2% of the surface quality. The humidity of the curing environment is controlled below 50%.

[0084] Comparative Example 3 (corresponding to Example 3, comparison of heavy-duty traffic road construction) 1. Material preparation: The dosage of carbide slag fly ash is adjusted to 10%, higher than 7% in Example 3. The proportion of graded crushed stone is reduced to 82%. The total dosage of the electrochemical activator is increased to 2%.

[0085] 2. Mixing: The mixing water ratio is increased to 12%, the stirring time is shortened to 3 minutes, and the uniform distribution is not concerned.

[0086] 3. Electrochemical activation: The electrochemical activation solution uses pure water instead of the weak alkaline calcium hydroxide solution, no external electric field treatment is applied, and the reaction only relies on natural diffusion.

[0087] 4. Compaction and forming: The compaction frequency is reduced to 15 Hz, the amplitude is controlled at 1 mm, and the compaction speed is increased to 6 m / min. Instead of forming in layers, the paving thickness is 30 cm at one time.

[0088] 5. Wet curing: The wet curing period is shortened to 3 days, the number of times of spraying water is 1 time / day, and the spraying amount is 0.5% of the surface quality. The influence of environmental temperature and humidity is not considered.

[0089] Comparative Example 4 (corresponding to Example 4, comparison of construction in cold environment) 1. Material preparation: The dosage of the antifreeze is adjusted to 0.2%, much lower than 1% in Example 4. Only sodium sulfate is used in the electrochemical activator, and the dosage is 0.5% of the total mass.

[0090] 2. Mixing: The water ratio is maintained at 8.5%, but the stirring time is reduced to 2 minutes, and the mixing is not sufficient. The uniformity of the particle size distribution of the materials is not considered.

[0091] 3. Electrochemical activation: The electric field treatment step is omitted, and only soaking in a weak alkaline solution (concentration 0.2%) for 5 minutes is used as the activation means.

[0092] 4. Compaction and forming: The single-layer thickness is adjusted to 10 cm, the vibration frequency is increased to 60 Hz (much higher than 40 Hz in Example 4), the amplitude is reduced to 1 mm, and the compaction speed is 5 m / min.

[0093] 5. Wet curing: The wet curing does not cover the thermal insulation material, and the temperature drops below -10 °C. The number of times of spraying water is 2 times per day, but the amount of each spraying is reduced to 0.2%.

[0094] Comparative Example 5 (corresponding to Example 5, for highway construction comparison) 1. Material preparation: The dosage of carbide fly ash is increased to 12%, and the proportion of graded gravel is reduced to 80%. The dosage of the antifreeze is 0.2%, much lower than 0.7% in Example 5.

[0095] 2. Mixing and mineralization treatment: No electrochemical activator is used, and only 10% of water is added for direct mixing. In the mineralization treatment, the carbon dioxide flow rate is increased to 3 m 3 / min, and the spraying time is reduced to 3 minutes.

[0096] 3. Compaction and molding: The single-layer paving thickness is 25 cm, the vibration frequency is adjusted to 10 Hz, the amplitude is maintained at 4 mm, and the compaction speed is increased to 5 m / min.

[0097] 4. Wet curing: The wet curing period is shortened to 5 days, the number of times of spraying water per day is 1 time, and the spraying amount is reduced to 0.1%.

[0098] Experiment 1: Compressive strength test: The experiment aims to test the difference in compressive strength between Example 1 of the present invention and Comparative Example 1 under different temperature conditions, and verify the technical effects of the optimized electrochemical activation treatment, mineralization technology and low-temperature wet curing.

[0099] Experimental steps: 1. Sample preparation: Specimens are prepared according to Example 1 and Comparative Example 1 respectively, with the specification of 100 mm×100 mm×100 mm cube.

[0100] Electrochemical activation treatment, compaction and molding are carried out according to their respective process parameters, and wet curing is completed (curing for 7 days).

[0101] 2. Test environment setting: Three temperature environments are set: low temperature (-5 °C), normal temperature (20 °C), high temperature (40 °C). The cured specimens are placed in the corresponding environments for 2 hours to balance the temperature.

[0102] 3. Compressive strength test: Use a compression testing machine to conduct compressive strength tests at a loading rate of 1 MPa / s and record the maximum failure load.

[0103] Each group of samples was tested 5 times, and the average value was taken as the final data.

[0104] 4. Data recording and analysis: After the tests, record the compressive strength data of each group and compare the performance differences between Example 1 and Comparative Example 1 under different temperature conditions.

[0105] Experimental data: Comparison of compressive strength between Example 1 and Comparative Example 1 under different temperature conditions In Example 1, the electrochemical activation treatment significantly improved the hydration efficiency of the material. Especially in a low-temperature environment, the continuously generated C-S-H gel and ettringite effectively filled the pore structure inside the material. In contrast, in Comparative Example 1, no electrochemical treatment was carried out, resulting in almost stagnant hydration reaction at low temperature, a relatively high internal porosity, and a significant decrease in compressive strength. The performance difference under low-temperature conditions illustrates the important role of the mineralization process in optimizing the densification of the material.

[0106] Under normal temperature conditions, the compressive strength of Example 1 remained at a relatively high level. Because the uniformly distributed C-S-H gel and calcium carbonate crystals formed a stable network structure, which could evenly disperse the applied load. In contrast, in Comparative Example 1, due to the lack of electrochemical activation and heat and moisture curing, the generated hydration products were unevenly distributed, resulting in insufficient local strength and relatively fast crack initiation. The experimental data clearly show that the optimization treatment not only improves the overall strength but also enhances the crack inhibition ability.

[0107] Under high-temperature conditions, the optimized heat and moisture curing measures and mineralization treatment in Example 1 enabled the material to exhibit stronger crack resistance. Although slight cracks appeared on the surface, they did not have a significant impact on the overall strength. In contrast, in Comparative Example 1, due to the lack of effective heat and moisture curing and heat preservation control, the surface dry shrinkage cracks expanded significantly, and the compressive strength decreased significantly. This difference further proves that the comprehensive performance optimization of the material in different environments is closely related to the generation of mineralization and hydration products.

[0108] Experiment 2: Evaluation of crack control ability: This experiment aims to evaluate the crack control ability of Example 2 and Comparative Example 2 in a humid and hot environment (35 °C, 90% humidity), and focus on analyzing the effect of the optimized mineralization treatment on inhibiting crack formation.

[0109] 1. Experimental procedures: Sample preparation: Prepare specimens of 100mm×100mm×50mm according to Example 2 and Comparative Example 2 respectively, and prepare 5 samples for each group.

[0110] After molding, cure them in a wet environment for 7 days to ensure the initial strength is reached.

[0111] 2. Curing in a humid and hot environment: Put the samples into a humid and hot test chamber, set the temperature at 35°C, and control the humidity at 90%. Extend the curing time to 14 days, and record the changes on the surface of the specimens every day.

[0112] 3. Crack detection: Use a crack microscopic imaging device for crack detection, and record the number, length, and width of surface cracks.

[0113] Take three images of each sample and take the average value.

[0114] Define cracks with a width greater than 0.1mm as effective cracks, and record their total length and area.

[0115] 4. Data recording and analysis: Compare the total area, total length, and incidence of crack distribution of the samples in Example 2 and Comparative Example 2, and analyze the contribution of the optimized mineralization treatment to crack control.

[0116] Experimental data: Comparison of crack distribution between Example 2 and Comparative Example 2 in a humid and hot environment Experimental summary: The differences in the number and distribution of cracks are very obvious. The number of cracks in Example 2 is significantly reduced, and both the length and width are controlled within a lower range. Under humid and hot conditions, the calcium carbonate crystals generated by the mineralization treatment have a very direct inhibitory effect on cracks. These crystals fill the fine pores and micro-cracks, making it difficult for cracks to expand. Especially when the surface of the material is affected by humidity and temperature, the surface hydration products also play an important protective role. In Comparative Example 2, due to insufficient mineralization treatment, cracks are generated and expanded rapidly, and the internal tension of the material is not relieved.

[0117] The difference in crack area further reveals the synergistic effect of mineralization and wet curing. In Example 2, the optimization of the CO 2 flow rate and spraying time promotes the uniform deposition of calcium carbonate, which not only significantly enhances the surface densification but also provides support for the crack resistance of the material inside. In Comparative Example 2, due to low mineralization efficiency, after the surface cracks are exposed, the humid and hot environment further accelerates the crack expansion. At the same time, the fewer wet curing times cannot provide enough moisture support, and the cracks expand significantly in width and depth.

[0118] The influence of humid heat conditions on the crack distribution of materials is very complex, but the crack control ability shown in Example 2 illustrates the importance of optimizing the mineralization technology. Obviously, the number and distribution of cracks are not only related to the material composition, but also closely related to the efficiency of hydration and mineralization treatments after molding. Experiments show that the calcium carbonate crystals formed by mineralization in Example 2 play a very crucial role, building a strong microscopic structure barrier and making the material more adaptable to complex humid heat environments.

[0119] Experiment 3: Frost and thaw cycle resistance performance test: This experiment aims to evaluate the frost and thaw cycle resistance of Example 3 and Comparative Example 3 under heavy traffic conditions, and analyze the improvement effects of the optimized antifreeze, electrochemical activation treatment, and compaction molding on the frost and thaw resistance performance.

[0120] 1. Experimental procedure: Sample preparation: Prepare specimens according to Example 3 and Comparative Example 3 respectively, with the size of 100mm×100mm×100mm cubes, and prepare 5 pieces for each group.

[0121] After curing for 7 days, place them at room temperature to balance the humidity for 12 hours.

[0122] 2. Frost and thaw cycle test: Use a frost and thaw cycle device, set the temperature range from -10°C to 10°C, and each cycle is 12 hours (6 hours of freezing and 6 hours of thawing).

[0123] Conduct 50 frost and thaw cycles, and record the mass change and volume change of the samples during the frost and thaw process.

[0124] 3. Compressive strength test: After the frost and thaw cycles, take out the specimens and conduct a compressive strength test with a loading rate of 1MPa / s, and record the maximum failure load.

[0125] 4. Volume change test: Use the water displacement method to measure the volume change of the specimens before and after frost and thaw, and record the expansion rate.

[0126] Each specimen is tested 3 times, and the average value is taken.

[0127] 5. Data recording and analysis: Compare the differences in the strength retention rate and volume change rate of the samples of Example 3 and Comparative Example 3 after frost and thaw.

[0128] Experimental data: Comparison of strength and volume changes of Example 3 and Comparative Example 3 after frost and thaw cycles The compressive strength after freeze-thaw cycles in Example 3 is excellent, and the strength retention rate is always above 80%. The addition of the antifreeze effectively reduces the freezing point of water under low-temperature conditions and decreases the volume expansion during freezing. Meanwhile, the optimized electrochemical activation treatment enables a more complete hydration reaction, and the generated C-S-H gel and ettringite are evenly distributed, further enhancing the stability of the internal structure of the material. In contrast, the strength retention rate in Comparative Example 3 is generally lower than 65% because the lack of antifreeze results in rapid crack propagation during freeze-thaw cycles, a fragile structure, and fast failure.

[0129] The results of the volume expansion rate further illustrate that the microstructure of Example 3 is more stable during freeze-thaw cycles. The calcium carbonate crystals generated by carbon dioxide mineralization fill the fine pores of the material, effectively inhibiting the excessive infiltration of moisture and the expansion after freezing. In Comparative Example 3, due to the lack of electrochemical activation, the mineralization effect is insufficient, moisture easily accumulates in the pores, and the expansion rate after freeze-thaw cycles exceeds 5%, showing obvious volume damage. This difference clearly demonstrates the freeze-thaw resistance of the optimized process.

[0130] The damage to the material by freeze-thaw cycles is multi-dimensional, but the optimized compaction and forming parameters in Example 3 provide a higher density, which significantly reduces the initiation and propagation of cracks. In Comparative Example 3, due to poor control of the vibration frequency and thickness, the compaction effect is uneven, and cracks accelerate to propagate during freeze-thaw cycles. Generally speaking, the overall performance advantages of Example 3 are fully verified in terms of compressive strength and volume stability.

[0131] Experiment 4: Durability test (resistance to water erosion): Evaluate the water erosion resistance of Example 4 and Comparative Example 4 in a water immersion environment, and focus on testing the effects of mineralization treatment and optimized wet curing on the densification and strength retention of the material.

[0132] 1. Experimental steps: Sample preparation: Prepare specimens according to Example 4 and Comparative Example 4 respectively, in the form of rectangular test blocks with dimensions of 100 mm × 100 mm × 50 mm, and prepare 5 samples for each group.

[0133] After forming, conduct wet curing for 7 days to ensure that the samples reach the initial strength.

[0134] 2. Water immersion treatment: Put the cured test blocks into a constant-temperature water bath, set the water temperature at 20°C, and soak for 72 hours.

[0135] Record the mass change of the test blocks before and after soaking, and calculate the mass change rate.

[0136] 3. Compressive strength test: After the water immersion test is completed, take out the test specimens, dry the surface moisture, and use a compression testing machine to measure the compressive strength at a loading rate of 1 MPa / s. Record the failure load.

[0137] Compare with the strength data of the non-water immersed specimens and calculate the strength retention rate.

[0138] 4. Data recording and analysis: Statistically analyze the mass change rate and strength retention rate of the samples, and analyze the difference in water erosion resistance between Example 4 and Comparative Example 4.

[0139] Experimental data: Test data on water erosion resistance of Example 4 and Comparative Example 4 From the mass change rate, it can be seen that the material of Example 4 shows extremely low water absorption under water erosion conditions. The mineralized calcium carbonate crystals tightly fill the pores between particles, and this microstructure greatly limits the infiltration of water. In Comparative Example 4, electrochemical activation was not used, resulting in insufficient mineralization efficiency, and there are still many open pores inside the material, leading to a significant increase in the mass change after water infiltration. This difference clearly reflects the direct effect of mineralization technology on water erosion resistance.

[0140] The samples of Example 4 retained about 90% of their strength after water immersion, which is much higher than about 60% of Comparative Example 4. The synergistic effect of electrochemical activation and wet curing significantly improves the uniformity of the hydration products, forming a dense and stable network structure. In Comparative Example 4, due to the insufficient amount of mineralized products, the microstructure is loose, and the strength decreases rapidly after being eroded by water. This shows that the durability of the material is closely related to the mineralization efficiency and pore closure degree.

[0141] Experiment 5: On-site road base construction simulation experiment: Through on-site construction simulation, evaluate the comprehensive performance of Example 5 and Comparative Example 5 under the construction conditions of highway base, and focus on testing the performance of the materials in terms of bearing capacity, crack control and compressive strength.

[0142] 1. Experimental steps: Sample preparation and paving: Prepare the mixtures according to the process parameters of Example 5 and Comparative Example 5 respectively, and lay them in layers with a standard construction equipment, with each layer having a thickness of 20 cm.

[0143] Use a vibrating roller for compaction, with the vibration frequencies of 50 Hz for Example 5 and 10 Hz for Comparative Example 5. The construction area of each group is 5 m × 5 m.

[0144] 2. Wet curing: Example 5: The wet curing period is 7 days, with water sprayed 3 times a day, and the spraying amount each time is 0.8%.

[0145] Comparative Example 5: The wet curing period is shortened to 5 days, with water sprayed 1 time a day, and the spraying amount is 0.1%.

[0146] 3. Performance testing: Bearing capacity test: Use a bearing modulus test device (such as an FWD device) to measure the resilient modulus of the base course. Test 10 points in each group and record the average value.

[0147] Crack detection: Record the crack distribution after construction through a crack scanner, including the number, width, and length of the cracks.

[0148] Compressive strength test: Take samples from the paved base course, cut them into standard cubes (100mm×100mm×100mm), and test the compressive strength.

[0149] 4. Environmental conditions: Simulate the construction environment temperature of 30°C and humidity of 70%. Keep the environmental conditions for 24 hours after testing before conducting performance detection.

[0150] Experimental data: Comparison of on-site construction simulation performance between Example 5 and Comparative Example 5 The bearing modulus of Example 5 is significantly higher than that of Comparative Example 5. This improvement stems from the dual optimization of mineralization and hydration reactions. The calcium carbonate crystals generated by the mineralization treatment significantly enhance the density of the material, and the optimized vibration compaction process further ensures uniform densification of each layer. In Comparative Example 5, due to insufficient vibration frequency and wet curing, there are more unclosed pores inside the material.

[0151] The data of crack distribution also clearly shows the differences between the two schemes. The number of cracks in Example 5 is much less than that in Comparative Example 5, and the width is always controlled below 0.15mm. This is inseparable from the optimized wet curing. Especially in a construction environment with high humidity, the uniformly sprayed water provides additional protection for crack control. In Comparative Example 5, due to the short wet curing time and insufficient water replenishment, the surface dry shrinkage cracks rapidly expand, resulting in the crack width generally exceeding 0.3mm.

[0152] The compressive strength data further verifies the technical advantages of Example 5. The uniformly distributed C-S-H gel and calcium carbonate crystals form a stable microscopic network when bearing the load, ensuring high strength. In Comparative Example 5, due to insufficient mineralization and compaction, the strength distribution on the surface and inside of the material is uneven, and the overall strength is significantly lower than that of Example 5. This difference not only stems from the material preparation stage but also reflects the importance of construction parameters in the optimization process.

[0153] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for stabilizing graded crushed stone materials using calcium carbide fly ash, characterized in that: The following steps are involved: S1. Mix carbide fly ash and graded crushed stone in a mass ratio of 5% to 8% and 85% to 90%; S2. Adding an electrochemical activator to the mixture, wherein the electrochemical activator includes sodium sulfate and potassium chloride, and the total amount thereof is 1% to 2% of the mass of the mixture; S3, adding water to the mixture, wherein the proportion of the water is 8% to 12% of the mass of the mixture; S4, applying an electric field to the mixture in a weakly alkaline environment, with a voltage ranging from 5 to 15 volts and a treatment time of 20 to 30 minutes; S5, introducing gaseous carbon dioxide into the mixture after the electric field treatment, the carbon dioxide concentration is 5% to 10%, and the treatment time is 10 to 15 minutes; S6, compacting the treated mixture to a compacted density of more than 95% of the maximum theoretical density; S7. Carry out wet curing on the compacted materials for no less than 7 days, and control the humidity at 85% to 95%.

2. A method for stabilizing graded crushed stone materials using calcium carbide fly ash according to claim 1, characterized in that: The particle size of the graded crushed stone is less than 4.75 mm, accounting for 15% to 25% of the total mass of the crushed stone, wherein the portion of particles smaller than 0.075 mm does not exceed 10% of the total mass of fine particles.

3. The method for stabilizing graded crushed stone materials using calcium carbide fly ash according to claim 1, characterized in that: The average particle size of the calcium carbide fly ash is 50-70 μm, and the specific surface area of ​​the powder is 4000-6000 cm 2 / g, the free calcium oxide content of the calcium carbide fly ash is 15% to 25%, and the silicate content is 40% to 55%.

4. The method for stabilizing graded crushed stone materials using calcium carbide fly ash according to claim 1, characterized in that: The weak alkaline environment is prepared by dissolving calcium hydroxide, the solution concentration is 0.5% to 1.5%, and the temperature of the solution is controlled at 15° C. to 30° C.

5. The method for stabilizing graded crushed stone materials using carbide fly ash according to claim 1, characterized in that: The mass ratio of sodium sulfate to potassium chloride in the electrochemical activator is 1:1 to 3:

2. The electrochemical activator is added in the form of solid powder, and dissolves after being fully contacted with water in the mixture to activate the active components of calcium carbide fly ash.

6. The method for stabilizing graded crushed stone materials using carbide fly ash according to claim 1, characterized in that: The compaction speed of the compaction molding is 2-4 m / min, the compaction thickness of a single layer is 15-20 cm, the vibration frequency is 30-50 Hz, and the amplitude is controlled at 2-5 mm.

7. The method for stabilizing graded crushed stone materials using carbide fly ash according to claim 1, characterized in that: In the step of introducing carbon dioxide, the carbon dioxide gas is sprayed through a uniform distribution device arranged on the top of the reaction container, and the gas flow rate of the carbon dioxide is controlled at 0.5 to 1.5 m / s. 3 / min.

8. The method for stabilizing graded crushed stone materials using carbide fly ash according to claim 1, characterized in that: During the wet curing process, water is sprayed at least twice a day, and the amount of water sprayed each time is 0.5% to 1% of the surface mass of the mixture.

9. The method for stabilizing graded crushed stone materials using carbide fly ash according to claim 1, characterized in that: During the wet curing process, an antifreeze agent is added. The antifreeze agent is calcium chloride or calcium formate, and the amount thereof is 0.5% to 1% of the total mass of the mixture. In a cold environment, the temperature of the wet curing is controlled at 0°C to 5°C.

10. An application of the calcium carbide fly ash stabilized graded crushed stone material prepared by the method according to claim 1 in road base construction, characterized in that: The material is suitable for base construction of expressways and heavy-load traffic roads. The ambient temperature range of the construction area is ~10°C to 40°C, and the humidity range is 50% to 95%.

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