Roadbed structure based on slag-gypsum-based cementing material and construction process thereof

Abstract

The invention relates to the field of buildings, and particularly discloses a roadbed structure based on a slag-gypsum-based cementing material and a construction process of the roadbed structure. A roadbed structure based on a slag-gypsum-based cementing material is characterized by comprising the following raw materials in parts by weight: 60-70 parts of slag, 85-100 parts of industrial byproduct gypsum, 10-20 parts of cement, 40-50 parts of water, 5-7 parts of a composite alkali activator, 2-3 parts of calcium sulphoaluminate, 7-10 parts of organic silicon resin modified steel fibers, 3-4 parts of a water reducer and 250-300 parts of gravel. The organic silicon resin modified steel fiber comprises the following raw materials: hydrogen-containing organic silicon resin, polyborosiloxane and steel fiber in a mass ratio of 32: 1.6: (40-50). The slag-gypsum-based cementing material disclosed by the invention has the advantages that the crushing resistance is high, and the crack resistance of a cured roadbed structure is good.

Description

Technical Field

[0001] The present application relates to the field of construction, and more particularly, to a roadbed structure based on slag-gypsum-based cementitious materials and a construction process thereof. Background Art

[0002] In recent years, the preparation and application of gypsum-based cementitious materials have developed rapidly in China. Natural gypsum resources have been exhausted. The resource utilization of industrial by-product gypsum is an effective way to meet market demand and reduce environmental pollution. Industrial by-product gypsum refers to by-products or waste residues with CaSO4 as the main component generated by chemical reactions in industrial production, mainly including phosphogypsum, titanium gypsum, desulfurization gypsum, etc. By rationally utilizing the calcium, silicon, aluminum, sulfur and other components in the chemical composition of slag and industrial by-product gypsum, the preparation of solid waste-based cementitious materials can give full play to the performance advantages of solid waste, realize the reconstruction of solid waste performance and value, meet the performance requirements of infrastructure construction, and solve the problem of solid waste dumping occupying land and polluting the environment.

[0003] According to the existing relevant technology, the Chinese invention patent with application number CN202210438168.5 discloses a C70 high-performance concrete, which is characterized by being made of the following components by mass: 144-146 parts of water, 408-412 parts of cement, 19-21 parts of mineral powder, 1710-1730 parts of aggregate, 10.5-11 parts of admixture, 23-24 parts of hydration heat inhibitor, and 7-7.5 parts of lauric acid; the hydration heat inhibitor is coated with lauric acid and then added. This concrete is made by coating the hydration heat inhibitor with lauric acid, which does not have any effect in the initial stage. It will produce an inhibitory effect, accelerate the early hydration reaction, and as the temperature rises, the hydration heat inhibitor is released, thereby reducing the cracks in the concrete. It is suitable for construction in cold environments. However, due to excessive hydration reaction in the early stage of this concrete, the directional arrangement of calcium hydroxide crystals in the interface transition zone increases, the grain size increases, the brittleness of the interface transition zone increases, and the toughness decreases, which reduces the compressive strength of the pavement and causes cracks. In addition, the later hydration reaction is inhibited, which reduces the later strength of the concrete. During vehicle driving, the frequent rolling of the wheels on the road surface will also cause damage to the road surface and cause cracks.

[0004] In view of the above-mentioned related technologies, the inventors found that it is necessary to provide a roadbed structure of slag-gypsum based cementitious material with good crack resistance and a construction process thereof. Summary of the Invention

[0005] In order to improve the crack resistance of the roadbed structure after the cementitious material is cured, the present application provides a roadbed structure based on slag-gypsum based cementitious material and a construction process thereof.

[0006] In a first aspect, the present application provides a roadbed structure based on slag-gypsum-based cementitious materials, which adopts the following technical solutions: A roadbed structure based on a slag-gypsum-based cementitious material, comprising the following raw materials by weight: slag 60-70 parts, industrial by-product gypsum 85-100 parts, cement 10-20 parts, water 40-50 parts, composite alkaline activator 5-7 parts, calcium sulfoaluminate 2-3 parts, organic silicon resin modified steel fiber 7-10 parts, water reducing agent 3-4 parts, and gravel 250-300 parts. The raw materials of the organic silicon resin modified steel fiber include hydrogen-containing organic silicon resin, polysiloxane and steel fiber in a mass ratio of 32:1.6:40-50.

[0007] By using the above technical solution, by using slag and industrial by-product gypsum, the exploitation of natural resources can be reduced, thereby reducing energy consumption and carbon emissions, the composite alkaline activator and the water reducing agent contain high concentration of OH - ions, which can destroy the Si-O bonds and Al-O bonds in the slag glass body, causing the internal network structure to depolymerize, thereby releasing SiO4 4- and AlO4 5- tetrahedrons, and these active ions react with water to generate C-S-H gel and C-A-S-H gel to form a cementitious framework, which can significantly improve the activity of the slag, and the composite alkaline activator also has a significant accelerating effect, which can accelerate the hydration reaction process of the cementitious material, fill the pores with hydration products such as ettringite, and enhance the mechanical properties such as compressive strength of the cementitious material, and the addition of calcium sulfoaluminate can also promote the generation of hydration products such as ettringite to form a continuous and uniform spatial network framework in the cementitious material, further enhancing the strength of the cementitious material and reducing the generation of cracks in the solidified roadbed structure.

[0008] Silicone resin modified steel fiber has excellent weather resistance. When added to cementitious materials, it can significantly enhance the impact resistance and durability of cementitious materials, making them stable in complex environments. The silicon-oxygen bonds contained in silicone resin modified steel fiber can react with silicates in slag and calcium ions in gypsum to form Si-O-Ca bonds. The hydroxyl groups it contains can also form coordination bonds or hydrogen bonds with metal ions and sulfate ions in slag, further enhancing the interfacial bonding strength between the two. It also reacts with active SiO2 and Al2O3 in slag through silanol bonds to accelerate the hydration process and generate a denser CSH gel, which not only enhances the silicone The bonding strength between resin-modified steel fibers and inorganic cementitious materials also improves the compressive strength of cementitious materials, thereby reducing the occurrence of cracks in roadbed structures. In addition, the addition of silicone resin-modified steel fibers can form a three-dimensionally distributed reinforcement network within the material. When there is external pressure, the steel fibers play a bridging role, spanning microcracks and bearing tensile stress, making the cementitious material exhibit good toughness, thereby inhibiting the expansion of microcracks and macrocracks; water reducers can improve the dispersibility of fibers and other components. By using them in combination, they can reduce the agglomeration of components such as silicone resin-modified steel fibers in the cementitious material, thereby further enabling it to play its role.

[0009] Optionally, the preparation method of the organosilicon resin modified steel fiber is: S1: dissolving hydrogenated organosilicon resin in xylene, adding polyborosiloxane and platinum catalyst, charging with nitrogen at 80-90°C, reacting for 1-2 hours, raising the temperature to 150-180°C, reacting for 3-4 hours, and grinding into powder after cooling to obtain modified organosilicon. The platinum catalyst is 2.5-3% by mass of the polyborosiloxane; S2: Plasma treating the steel fiber for 3-5 min, washing, and drying to obtain modified steel fiber; S3: Using the modified steel fiber obtained in S2 as a receiving substrate, the modified silicone obtained in S1 is subjected to electrostatic spraying technology, and then dried at 60-70°C for 12-14h to obtain silicone resin modified steel fiber.

[0010] By adopting the above technical solution, the hydrogen-containing silicone resin is reacted with polyborosiloxane, and the Si-OB bond is generated between the two through the interaction between the BO bond and the Si-O bond, thereby enhancing the intermolecular force. Due to its high loss performance, it can absorb and dissipate energy, so that the steel fiber can effectively reduce the impact of vibration and impact, improve the compressive strength and stability, and the hydrogen-containing silicone resin combined with polyborosiloxane improves the dispersion and fluidity of the steel fiber in the cementitious material, and can make the steel fiber act as a bridge evenly in the matrix. Therefore, after the modified silicone powder is sprayed on the surface of the steel fiber, it can not only enhance the steel fiber, but also improve the mechanical properties of the steel fiber. The steel fiber surface is introduced with plasma technology to form a hydrogen bond network with the hydroxyl group of the modified organic silicon powder, thereby enhancing the bonding strength between the steel fiber and the modified organic silicon powder, making it less likely to fall off. In addition, the hydroxylated steel fiber improves its hydrophilicity, improves the wetting effect between the steel fiber and the cementitious material matrix, enhances the dispersion of the steel fiber in the matrix, and enables it to play a bridging role in the matrix, thereby improving the compressive strength of the material and reducing the occurrence of cracks in the roadbed structure.

[0011] Optionally, the modified silicone is pretreated as follows before electrostatic spraying: The modified organosilicon and 5-aminotetrazole are uniformly mixed in a dimethyl sulfoxide solvent, triruthenium dodecacarbonyl is added, and the mixture is reacted at 120-150° C. for 24-26 hours. After the reaction is completed, the mixture is separated on a chromatography column to obtain a pretreated modified organosilicon. The mass ratio of the modified organosilicon, 5-aminotetrazole, and triruthenium dodecacarbonyl is 32:85-87:0.32.

[0012] By adopting the above technical solution, triruthenium dodecacarbonyl is used as a catalyst to catalyze the dehydrogenation coupling reaction between hydrogen-containing silicone resin and 5-aminotetrazole, so that the modified silicone molecular chain is endowed with nitrogen heterocycles to form nitrogen heterocyclic organosilanes. By introducing the rigid structure of nitrogen heterocycles into its molecular chain, the movement of the silicone molecular chain is restricted. After the addition of the cementitious material, the structural strength of the cementitious material is improved, and the development of cracks in the roadbed structure after curing is slowed down, thereby extending the service life of the road.

[0013] Optionally, the steel fiber undergoes the following pretreatment before plasma treatment: Under argon protection, the film was etched using a fiber laser beam at a wavelength of 1064 nm for 3-5 minutes, washed, and then dried.

[0014] By adopting the above technical solution and etching the steel fiber surface with a fiber laser beam, a microscopic rough structure can be formed on the steel fiber surface, thereby enhancing the mechanical interlocking force and compatibility between the fiber and the cementitious material. This not only improves the interfacial bonding strength and mechanical properties, but also reduces the agglomeration of the steel fibers by increasing the friction and bite force between the steel fibers and the components in the cementitious material, thereby enabling them to play a crack-blocking role and slowing down the development of road cracks. Moreover, the surface of the etched steel fiber is rough. The increased specific surface area can load more modified silicone powder, so that the steel fiber can fully absorb and dissipate energy under the load of the modified silicone powder, reduce agglomeration, further improve the compressive strength of the cementitious material, enhance its bearing capacity, and improve the crack resistance of the roadbed structure after the cementitious material is cured.

[0015] Optionally, the composite alkaline activator comprises calcium hydroxide and sodium silicate in a mass ratio of 1-1.5:1.2-1.3.

[0016] By adopting the above technical solution, calcium hydroxide and sodium silicate are used as activators to provide a higher liquid phase alkalinity, promote the dissolution and hydration reaction of active silicon oxide and aluminum oxide in the slag, and thus enhance the strength of the cementitious material; under the synergistic activation of calcium hydroxide and sodium silicate, the generated hydration products are intertwined with each other and fill the pores, making the structure of the hardened body more compact, thereby improving the strength and durability of the cementitious material; by adjusting the addition amount of calcium hydroxide and sodium silicate in the composite alkaline activator, the effect of the composite alkaline activator in the cementitious material can be maximized, and the setting time and hardening rate of the cementitious material can be controlled, thereby meeting the needs of different projects.

[0017] Optionally, 2-3 parts of carbon dioxide foam are added to the slag-gypsum based cementitious material.

[0018] By adopting the above technical solution, the carbon dioxide in the foam can react with the Ca in the gelling material. 2+ The reaction generates CaCO3 crystals, which enhance the friction between the matrices and generate cohesive force. Therefore, the yield stress of the cementitious material increases, optimizing its overall performance. Moreover, the formed CaCO3 makes the pore surface of the cementitious material more complex and rough, which is not only conducive to more uniform stress distribution, improving the strength of the cementitious material, and optimizing the macro and micro properties, but also can fill the tiny pores between the silicone resin modified steel fiber and the matrix, enhancing the bonding force between the silicone resin modified steel fiber and the cementitious material. In addition, the addition of carbon dioxide foam consumes Ca(OH)2, promotes the hydration reaction of the group, increases the formation of CHS gel and ettringite, further enhances the compressive strength of the cementitious material, and reduces the occurrence of cracks in the roadbed structure.

[0019] Optionally, the carbon dioxide foam is prepared by: S1: uniformly mixing polyoxyethylene alkyl alcohol amide and sodium lauryl sulfonate to prepare a liquid foaming agent; S2: placing the liquid foaming agent obtained in S1 into a foaming agent, introducing carbon dioxide at 33-35° C., and foaming for 20-30 minutes to obtain carbon dioxide foam, wherein the mass ratio of polyoxyethylene alkyl alcohol amide to sodium lauryl sulfate is 1:0.5-0.7.

[0020] By adopting the above technical solution, carbon dioxide has a high solubility in water and can easily penetrate the liquid film to accelerate the fusion of foam, making it difficult for the foam to remain stable and quickly decay, and unable to be effectively dispersed in the gelling material. Polyoxyethylene alkyl alcohol amide is used as a foaming agent, which not only has a good foaming effect, so that carbon dioxide can effectively generate and stabilize foam during foaming, but also can increase the viscosity of the foam system, which helps to improve the stability and durability of the foam. Sodium dodecyl sulfate is used as a foam stabilizer, and its hydrophobic alkyl chains are oriented at the interface to form a dense molecular film, which enhances the anti-disturbance ability of the liquid film, and significantly reduces the surface tension and interfacial tension of water, reduces foam decay, and thus effectively disperses the carbon dioxide foam in the matrix. When the carbon dioxide foam is fully and evenly dispersed in the matrix, it cracks and releases carbon dioxide, which can react with the Ca in the matrix. 2+ The CaCO3 crystals generated by the reaction are more evenly distributed and the reaction rate is controlled, thus avoiding the accumulation of crystals in the cementitious material and destroying the overall density and bearing capacity of the material, further improving the compressive strength of the cementitious material and slowing down the development of cracks in the roadbed structure after solidification.

[0021] In a second aspect, the present application provides a construction process for a roadbed structure based on slag-gypsum-based cementitious materials, which adopts the following technical solutions: A construction process for a roadbed structure based on slag-gypsum-based cementitious materials comprises the following steps: S1: Roadbed leveling: After removing the road surface rocks, compact the roadbed, upper embankment and lower embankment; S2: Raw material mixing: Mix the raw materials evenly according to the formula to prepare slag-gypsum based cementitious material, and add crushed stone to obtain a mixture; S3: Spreading, shaping, and rolling: Spread and shape the mixture obtained in S2, and roll it when the moisture content of the mixture is 1-2%; S4: Curing: After compaction is completed, watering and curing are carried out for 7-10 days.

[0022] By adopting the above technical solution, this construction method can keep the road surface uniform and flat. Through paving, shaping and rolling, it can not only improve the density and adhesion of the road surface, but also improve the quality of the road surface. The road surface after maintenance can effectively extend its service life and prevent premature damage to the road surface.

[0023] Optionally, the slag-gypsum based cementitious material in step S2 is prepared by the following steps: S1: drying, grinding and uniformly mixing slag and industrial by-product gypsum to prepare a mixture; S2: Cement, calcium sulfoaluminate and the mixture obtained in S1 are uniformly mixed, and after ball milling in a ball mill for 5-10 minutes, silicone resin-modified steel fiber is added, and a water-soluble water-reducing agent and a composite alkaline activator are added and continued to grind for 10-15 minutes to obtain a slag-gypsum-based cementitious material.

[0024] By adopting the above technical solution, slag, industrial by-product gypsum, cement, water, composite alkaline activator, silicone resin modified steel fiber, water reducer and crushed stone are evenly mixed according to the formula, so that the function of each component can be maximized, and ball milling is carried out in a ball mill to refine the particle size, increase the specific surface area and active sites, and thus enhance the reaction activity.

[0025] In summary, this application has the following beneficial effects: 1. Since this application uses slag, industrial by-product gypsum, cement, water, composite alkaline activator, calcium sulfoaluminate, silicone resin modified steel fiber, water reducer and crushed stone as raw materials, the silicone resin modified steel fiber can significantly improve the impact resistance of the cementitious material, and can form a three-dimensionally distributed reinforcement network inside the cementitious material and be evenly dispersed in the matrix, thereby improving the compressive strength of the cementitious material and reducing the development of cracks in the roadbed structure.

[0026] 2. In the present application, it is preferred to combine hydrogen-containing silicone resin with polyborosiloxane to form Si-OB bonds to enhance intermolecular forces. The combined modified silicone has good high loss and dispersibility. When sprayed on the surface of the steel fiber, it can absorb and dissipate energy, thereby improving the compressive strength of the steel fiber in the cementitious material and making it less likely to agglomerate, fully playing the role of a bridge, thereby improving the compressive strength of the cementitious material and reducing the occurrence of cracks in the roadbed structure. The hydroxylated steel fiber forms a hydrogen bond network with the hydroxyl group of the modified silicone powder by introducing hydroxyl groups, thereby enhancing the bonding strength between the two and making it less likely to fall off. It can fully give play to the advantages of compressive performance and dispersibility, so that the steel fiber is evenly distributed in the cementitious material and plays a bridging role, reducing the occurrence of cracks in the roadbed structure after curing.

[0027] 3、The application introduces nitrogen heterocycle on the molecular chain of organic silicon by dehydrogenation coupling reaction between modified organic silicon and 5-amino tetrazole, improves the structural strength of cementitious material, and reduces the crack generation of roadbed structure; the surface of steel fiber is etched by fiber laser beam, which increases the specific surface area and makes it more rough, enhances the mechanical embedding force with the matrix, and also can load more modified organic silicon powder, improves the compressive strength and dispersibility of steel fiber, further improves the mechanical properties of cementitious material, and reduces the crack generation of roadbed structure; carbon dioxide foam can form CaCO3 by consuming Ca(OH)2, which makes the internal structure of cementitious material more rough and complex, and fills the gap between modified steel fiber and matrix, further improves the compressive strength of cementitious material, and reduces the crack generation of roadbed structure. DETAILED DESCRIPTION

[0028] The following examples further illustrate the application.

[0029] Preparation examples 1-9 of modified organic silicon resin Preparation example 1: S1: 1.5 g of hydroxyl-terminated polydimethylsiloxane and 0.01 g of boric acid were uniformly mixed and placed in a vacuum kneader, sealed, and heated to 150℃ for 5 h to obtain polysiloxane. The hydroxyl-terminated polydimethylsiloxane was selected from Shenzhen Jipeng Silicon Fluorine Material, with a product number of 20240520002; S2: 32 g of hydrogen-containing organic silicon resin was dissolved in 100 mL of xylene, 1.6 g of polysiloxane obtained in S1 and 0.048 g of platinum catalyst were added, heated to 90℃, and nitrogen was filled for 1 h. Then the temperature was continuously increased to 180℃ and reacted for 3 h. After cooling to room temperature, the powder with a particle size of 50 μm was ground to obtain modified organic silicon. The hydrogen-containing organic silicon resin was selected from Shandong Moore Chemical Industry, with a product number of 01, and the platinum catalyst was selected from Shanghai Siliconbao High-tech Material, with a product number of Pt-50; S3: 50 g of steel fiber was treated by plasma for 5 min, washed and dried at 60℃ for 12 h to obtain modified steel fiber. The treatment power was 100 W, the oxygen flow rate was 10 sccm, and the pressure was 10 Pa. The steel fiber was selected from Shandong Hongshuo New Material, with a length of 25 mm; S4: The modified steel fiber obtained in S3 was used as a receiving substrate, and the modified organic silicon obtained in S2 was subjected to electrostatic spraying technology, and then dried at 60℃ for 14 h to obtain organic silicon resin modified steel fiber. The push injection speed of electrostatic spraying was 0.03 mm / min, the negative voltage was -2.01 kV, the positive voltage was 6.8 kV, the receiving distance was 15 cm, and the receiving time was 3 min.

[0030] Preparation Example 2: S1: 1.5 g of hydroxyl-terminated polydimethylsiloxane and 0.01 g of boric acid were mixed evenly, placed in a vacuum kneader, sealed, heated to 150° C., and reacted for 5 h to obtain polyborosiloxane. The hydroxyl-terminated polydimethylsiloxane was selected from Shenzhen Jipeng Silicon Fluoride Materials, with a product number of 20240520002. S2: 32 g of hydrogenated organosilicon resin was dissolved in 100 mL of xylene, and 1.6 g of the polyborosiloxane obtained in S1 and 0.04 g of a platinum catalyst were added. The temperature was raised to 80° C., nitrogen was introduced, and the reaction was carried out for 2 h. The temperature was further raised to 150° C. and the reaction was carried out for 4 h. The mixture was cooled at room temperature and ground into a powder with a particle size of 50 μm to obtain a modified organosilicon. The hydrogenated organosilicon resin was selected from Shandong Moore Chemical and has a product number of 01. The platinum catalyst was selected from Shanghai Sibao High-tech Materials and has a product number of Pt-50. S3: 40 g of steel fiber was plasma treated for 3 min, washed, and dried at 60°C for 12 h to obtain modified steel fiber. The power during treatment was 100 W, the oxygen flow rate was 10 sccm, and the pressure was 10 Pa. The steel fiber was selected from Shandong Hongshuo New Materials and had a length of 25 mm. S4: Using the modified steel fiber obtained in S3 as the receiving substrate, the modified silicone obtained in S2 was subjected to electrostatic spraying technology, and then dried at 60°C for 14 hours to obtain silicone resin modified steel fiber. The electrostatic spraying injection speed was 0.03mm / min, the negative voltage was -2.01kV, the positive voltage was 6.8kV, the receiving distance was 15cm, and the receiving time was 3min.

[0031] Preparation Example 3: The difference from Preparation Example 1 is that polyborosiloxane is replaced by an equal amount of hydrogenated silicone resin, ground into a powder with a particle size of 50 μm, and sprayed on 50 g of modified steel fiber. Other operations are the same as Preparation Example 1.

[0032] Preparation Example 4: The difference from Preparation Example 1 is that the hydrogen-containing silicone resin is replaced by an equal amount of polyborosiloxane, ground into a powder with a particle size of 50 μm, and sprayed on 50 g of steel fiber. The other operations are the same as those in Preparation Example 1.

[0033] Preparation Example 5: The difference from Preparation Example 1 is that polyborosiloxane and hydrogen-containing silicone resin are not added. The specific steps are: only 50g of steel fiber is plasma treated for 5 minutes, washed and dried at 60°C for 12 hours to obtain modified steel fiber. The power during treatment is 100W, the oxygen flow rate is 10sccm, and the pressure is 10Pa. The steel fiber is selected from Shandong Hongshuo New Materials and has a length of 25mm.

[0034] Preparation Example 6: The difference from Preparation Example 1 is that the modified silicone is pretreated as follows before electrostatic spraying: 32 g of modified organosilicon and 85 g of 5-aminotetrazole were mixed evenly in 1 L of dimethyl sulfoxide solvent, 0.32 g of triruthenium dodecacarbonyl was added, and then reacted at 120° C. for 26 h. The catalyst and unreacted raw materials were removed by separation through a chromatographic column to obtain pretreated modified organosilicon.

[0035] Preparation Example 7: The difference from Preparation Example 6 is that the parameters during the modified silicone treatment are different. The specific steps are as follows: 32 g of modified organosilicon and 87 g of 5-aminotetrazole were mixed evenly in 1 L of dimethyl sulfoxide solvent, 0.32 g of triruthenium dodecacarbonyl was added, and then reacted at 150° C. for 24 h. The catalyst and unreacted raw materials were removed by separation through a chromatographic column to obtain a pretreated modified organosilicon.

[0036] Preparation Example 8: The difference from Preparation Example 6 is that the steel fiber is pretreated as follows before plasma treatment. The specific steps are as follows: Under argon protection, the steel fiber was etched with a fiber laser beam at a wavelength of 1064 nm for 3 min, washed, and dried at 60°C for 12 h.

[0037] Preparation Example 9: The difference from Preparation Example 8 is that the parameters of steel fiber pretreatment are different. The specific steps are as follows: Under argon protection, the steel fiber was etched with a fiber laser beam at a wavelength of 1064 nm for 5 min, washed, and dried at 60°C for 12 h. Example

[0038] Example 1: A roadbed structure based on slag-gypsum-based cementitious materials, the raw material dosage is shown in Table 1, the silicone resin modified steel fiber is made by Preparation Example 1, the cement is selected from P.O42.5 silicate cement, the composite alkaline activator is calcium hydroxide and sodium silicate in a mass ratio of 1:1.2, the sodium silicate is selected from Jinan Jiyang Hongfa Chemical Business Department, the item number is 88, the calcium sulfoaluminate is selected from Zhengzhou Jianwen Special Materials Technology, the item number is 20089, the water reducer is a polycarboxylic acid water reducer, selected from Century Tuoda (Hubei) New Materials, model number 2151256, and the gravel particle size is 10 mm.

[0039] The preparation method of the slag-gypsum based cementitious material comprises the following steps: S1: Drying slag and industrial by-product gypsum at 60° C. for 12 h, grinding and mixing uniformly to prepare a mixture according to weight; S2: Cement, calcium sulfoaluminate and the mixture obtained in S1 are mixed evenly, and ball-milled in a ball mill for 5 minutes. Silicone resin-modified steel fiber is added, and a water reducer and a composite alkaline activator are dissolved in water. After adding, grinding is continued for 10 minutes to obtain a mixture with a particle size of 70 μm, which is a slag-gypsum-based cementitious material.

[0040] A construction process for a pavement structure based on slag-gypsum-based cementitious materials comprises the following steps: S1: Roadbed leveling: After removing the road surface rocks, compact the roadbed, upper embankment and lower embankment. The compaction degree of the roadbed is ≥96%, the compaction degree of the upper embankment is ≥94%, and the compaction degree of the lower embankment is ≥93%; S2: Raw material mixing: crushed stone and slag-gypsum based cementitious material are mixed evenly according to the formula to prepare a mixture; S3: Spreading, shaping, and rolling: Spread and shape the mixture obtained in S2 using a paver, and roll it when the moisture content of the mixture reaches 1%; S4: Curing: After compaction, cover the surface of the pavement base with a layer of geotextile and carry out watering and curing for 7 days.

[0041] Table 1 Amount of raw materials used in Examples 1-5 Example 2: A roadbed structure based on slag-gypsum-based cementitious materials, the raw material dosage of which is shown in Table 1, the silicone resin modified steel fiber is made by Preparation Example 2, the cement is selected from P.O42.5 silicate cement, the composite alkaline activator is calcium hydroxide and sodium silicate in a mass ratio of 1.5:1.3, the sodium silicate is selected from Jinan Jiyang Hongfa Chemical Business Department, item number 88, calcium sulfoaluminate is selected from Zhengzhou Jianwen Special Materials Technology, item number 20089, the water reducer is a polycarboxylic acid water reducer, selected from Century Tuoda (Hubei) New Materials, model number 2151256, and the gravel particle size is 10 mm.

[0042] The method for preparing the slag-gypsum based cementitious material comprises the following steps: S1: Drying slag and industrial by-product gypsum at 60° C. for 12 h, grinding and mixing uniformly to prepare a mixture according to weight; S2: Mix cement and the mixture obtained in S1 evenly, ball-mill for 10 minutes, add silicone resin-modified steel fiber, dissolve the water reducer and composite alkaline activator in water, and continue grinding for 15 minutes to obtain a mixture with a particle size of 70 μm, which is a slag-gypsum-based cementitious material.

[0043] A construction process for a pavement structure based on slag-gypsum-based cementitious materials comprises the following steps: S1: Roadbed leveling: After removing the road surface rocks, compact the roadbed, upper embankment and lower embankment. The compaction degree of the roadbed is ≥96%, the compaction degree of the upper embankment is ≥94%, and the compaction degree of the lower embankment is ≥93%; S2: Raw material mixing: crushed stone and slag-gypsum based cementitious material are mixed evenly according to the formula to prepare a mixture; S3: Spreading, shaping, and rolling: Spread and shape the mixture obtained in S2 using a paver, and roll it when the moisture content of the mixture reaches 2%. S4: Curing: After compaction, cover the surface of the pavement base with a layer of geotextile and carry out watering and curing for 10 days.

[0044] Example 3: A roadbed structure based on slag-gypsum-based cementitious materials. The difference from Example 1 is that the amounts of raw materials used are different. The amounts of raw materials used are shown in Table 1.

[0045] Example 4: A roadbed structure based on slag-gypsum-based cementitious materials. The difference from Example 1 is that the amounts of raw materials used are different. The amounts of raw materials used are shown in Table 1.

[0046] Example 5: A roadbed structure based on slag-gypsum-based cementitious materials. The difference from Example 1 is that the amounts of raw materials used are different. The amounts of raw materials used are shown in Table 1.

[0047] Example 6: A roadbed structure based on slag-gypsum-based cementitious materials, which differs from Example 1 in that the silicone resin-modified steel fiber is made from Preparation Example 6.

[0048] Example 7: A roadbed structure based on slag-gypsum-based cementitious materials, which differs from Example 6 in that the silicone resin-modified steel fiber is made from Preparation Example 7.

[0049] Example 8: A roadbed structure based on slag-gypsum-based cementitious materials, which differs from Example 6 in that the silicone resin-modified steel fiber is made from Preparation Example 8.

[0050] Example 9: A roadbed structure based on slag-gypsum-based cementitious materials, which differs from Example 8 in that the silicone resin-modified steel fiber is made from Preparation Example 9.

[0051] Example 10: A roadbed structure based on slag-gypsum-based cementitious material. The difference from Example 8 is that 3 kg of carbon dioxide foam is added to the slag-gypsum-based cementitious material. The preparation method of the carbon dioxide foam is as follows: S1: Dissolve 1g of polyoxyethylene alkylolamide and 0.5g of sodium lauryl sulfonate in 50mL of water and mix well to prepare a liquid foaming agent; S2: Place the liquid foaming agent obtained in S1 in a foaming machine, introduce carbon dioxide at 35°C, and foam for 20 minutes to obtain carbon dioxide foam with a foam density of 98 kg / m 3 ; The preparation method of the slag-gypsum based cementitious material comprises the following steps: S1: Drying slag and industrial by-product gypsum at 60° C. for 12 h, grinding and mixing uniformly to prepare a mixture according to weight; S2: Cement, calcium sulfoaluminate and the mixture obtained in S1 are mixed evenly, and after ball milling for 5 minutes in a ball mill, silicone resin-modified steel fiber is added, and a water reducer and a composite alkaline activator are dissolved in water. After adding, grinding is continued for 10 minutes, and carbon dioxide foam is added and mixed evenly to obtain a mixture with a particle size of 70 μm, which is a slag-gypsum-based cementitious material.

[0052] Example 11: A roadbed structure based on slag-gypsum-based cementitious material. The difference from Example 8 is that 2 kg of carbon dioxide foam is added to the slag-gypsum-based cementitious material. The preparation method of the carbon dioxide foam is as follows: S1: Dissolve 1g of polyoxyethylene alkylolamide and 0.7g of sodium lauryl sulfonate in 50mL of water and mix well to prepare a liquid foaming agent; S2: Place the liquid foaming agent obtained in S1 in a foaming machine, introduce carbon dioxide at 33°C, and foam for 30 minutes to obtain carbon dioxide foam with a foam density of 98 kg / m 3 ; The preparation method of the slag-gypsum based cementitious material comprises the following steps: S1: Drying slag and industrial by-product gypsum at 60° C. for 12 h, grinding and mixing uniformly to prepare a mixture according to weight; S2: Cement, calcium sulfoaluminate and the mixture obtained in S1 are mixed evenly, and after ball milling for 5 minutes in a ball mill, silicone resin-modified steel fiber is added, and a water reducer and a composite alkaline activator are dissolved in water. After adding, grinding is continued for 10 minutes, and carbon dioxide foam is added and mixed evenly to obtain a mixture with a particle size of 70 μm, which is a slag-gypsum-based cementitious material.

[0053] Comparative Example Comparative Example 1: A roadbed structure based on slag-gypsum-based cementitious materials, which differs from Example 1 in that the silicone resin-modified steel fiber is made from Preparation Example 3.

[0054] Comparative Example 2: A roadbed structure based on slag-gypsum-based cementitious materials, which differs from Example 1 in that the organosilicon resin-modified steel fiber is made from Preparation Example 4.

[0055] Comparative Example 3: A roadbed structure based on slag-gypsum-based cementitious materials, which differs from Example 1 in that the silicone resin-modified steel fiber is made from Preparation Example 5.

[0056] Comparative Example 4: A roadbed structure based on slag-gypsum-based cementitious materials, which differs from Example 1 in that no organosilicon resin-modified steel fiber is added.

[0057] Comparative Example 5: A roadbed structure based on slag-gypsum-based cementitious materials, which differs from Example 1 in that the amount of silicone resin-modified steel fiber added is 15 kg.

[0058] Performance testing A roadbed structure based on slag-gypsum-based cementitious materials was prepared according to the methods in the examples and comparative examples, and performance tests were performed according to the following methods: 1. Mechanical properties test: The prepared roadbed structure based on slag-gypsum-based cementitious materials was used as a specimen. According to GB / T50081-2002 "Standard for Test Methods for Mechanical Properties of Ordinary Concrete", it was placed in a 20 mm × 20 mm × 20 mm steel mold and formed. After being placed in a room for 24 hours, the mold was removed and then placed in a curing room with a temperature of (20 ± 2) ° C and a humidity of ≥ 90% for 28 days. The flexural strength and compressive strength tests were carried out using a YAW-300C fully automatic constant stress cement concrete flexural and compressive strength testing machine. The specific results are shown in Table 2.

[0059] 2. Crack resistance test: The prepared roadbed structure based on slag-gypsum-based cementitious material was used as a specimen. Referring to GB / T 50081-2002 "Standard for Test Methods for Mechanical Properties of Ordinary Concrete", its crack resistance was tested using a WAW-(1000) universal testing machine. Referring to T0573-2020 Test Method for Early Cracking Sensitivity of Cement Concrete (Plate Method), the total crack area per unit area was tested. The specific results are shown in Table 2.

[0060] Table 2 Compressive strength, flexural strength, cracking strength and total cracking area test According to the data in Table 2 and the raw material dosage in Table 1, the flexural strength, compressive strength and crack resistance of Examples 1-5 decrease with the decrease in the dosage of silicone resin modified steel fiber, and the total crack area increases. Therefore, it can be seen from the data that the addition of silicone resin modified steel fiber can enhance the flexural strength and compressive strength of the roadbed structure after the cementitious material is cured and maintained, and has a certain improvement effect on the crack resistance of the roadbed structure, reducing the occurrence of cracks.

[0061] The difference between Example 6-7 and Example 1 is that the silicone resin modified steel fiber is made from Preparation Example 6 and Preparation Example 7, respectively, and the modified silicone is pretreated before electrostatic spraying. Compared with Example 1, the flexural strength and compressive strength of Examples 6-7 are increased, the crack resistance is improved, and the total crack area is reduced. Therefore, it can be seen from the data that the introduction of a nitrogen heterocyclic rigid structure on the modified silicone molecular chain can improve the compressive strength and flexural strength of the roadbed structure after the cementitious material is cured, and has a significant improvement on the crack resistance of the roadbed structure, effectively reducing the development of cracks.

[0062] The difference between Example 8-9 and Example 6 is that the silicone resin modified steel fibers are made from Preparation Example 8 and Preparation Example 9, respectively, and the steel fibers are etched. Compared with Example 6, the flexural strength and compressive strength of Examples 8-9 are significantly increased, the crack resistance also increases accordingly, and the total crack area decreases. Therefore, from the data we can know that fiber laser beam etching treatment on the surface of the steel fibers can not only greatly improve the flexural strength and compressive strength of the roadbed structure after the cementitious material is cured, but also enhance the crack resistance of the roadbed structure after curing and reduce the development of cracks.

[0063] The difference between Example 10-11 and Example 8 is that carbon dioxide foam is further added to the cementitious material. Compared with Example 8, the flexural strength, compressive strength and crack resistance of Examples 10-11 are significantly increased, and the total crack area is reduced. It can be seen from the data that the fiber laser beam etching treatment on the surface of the steel fiber not only enhances the flexural strength and compressive strength of the roadbed structure, but also improves the crack resistance of the roadbed structure after curing, and can effectively reduce the development of cracks.

[0064] The difference between Comparative Example 1 and Example 1 is that the silicone resin modified steel fiber is made from Preparation Example 3, and an equal amount of hydrogen-containing silicone resin is used to replace polyborosiloxane. It can be seen from the data that compared with Example 1, the flexural strength and compressive strength of the roadbed structure sample decrease, the crack resistance decreases, and the total crack area increases. Therefore, the addition of polyborosiloxane can greatly improve the flexural and compressive strength of the material, and also has a corresponding improvement on the crack resistance of the roadbed structure, thereby reducing the occurrence of cracks in the roadbed structure.

[0065] The difference between Comparative Example 2 and Example 1 is that the silicone resin-modified steel fiber is made from Preparation Example 4, and the hydrogen-containing silicone resin is replaced by an equal amount of polyborosiloxane. It can be seen from the data that compared with Example 1, the flexural strength and compressive strength of Comparative Example 2 are reduced, the crack resistance is also reduced, and the total crack area is increased. Therefore, from the data we can know that by adding the hydrogen-containing silicone resin, the compressive strength of the roadbed structure after the cementitious material is cured is enhanced, and its crack resistance is improved, thereby reducing the development of cracks in the roadbed structure.

[0066] The difference between Comparative Example 3 and Example 1 is that the silicone resin modified steel fiber is made from Preparation Example 5, and no hydrogen-containing silicone resin and polyborosiloxane are added. It can be seen from the data that compared with Example 1, the flexural strength and compressive strength of Comparative Example 3 are greatly reduced, the crack resistance is greatly reduced, and the total crack area is increased. Therefore, loading hydrogen-containing silicone resin and polyborosiloxane can significantly improve the compressive strength and crack resistance of the roadbed structure after the cementitious material is cured, and has a significant effect on reducing the occurrence of cracks.

[0067] The difference between Comparative Example 4 and Example 1 is that no silicone resin modified steel fiber is added. It can be seen from the data that compared with Example 1, the flexural strength and compressive strength of Comparative Example 4 are greatly reduced, the crack resistance is significantly reduced, and the total crack area is significantly increased. Therefore, we can know that the addition of modified silicone resin can significantly improve the mechanical properties and crack resistance of the roadbed structure after the cementitious material is cured, and reduce the occurrence of cracks in the roadbed structure. Compared with Comparative Example 3, the flexural strength and compressive strength are significantly reduced, the crack resistance is reduced, and the total crack area is increased. Therefore, the addition of modified steel fiber also has a certain enhancement on the mechanical properties and crack resistance of the roadbed structure after the cementitious material is cured, thereby reducing the development of cracks in the roadbed structure.

[0068] The difference between Comparative Example 5 and Example 1 is that the addition amount of silicone resin modified steel fiber is 15 kg. It can be seen from the data that compared with Example 1, the flexural strength, compressive strength, crack resistance and total crack area of ​​Comparative Example 5 are not much different. Therefore, we can know that increasing the addition amount of modified silicone resin has little effect on improving the mechanical properties and crack resistance of the roadbed structure after the cementitious material is cured.

[0069] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A roadbed structure based on slag-gypsum based cementitious materials, characterized in that: The invention comprises the following raw materials in parts by weight: 60-70 parts of slag, 85-100 parts of industrial by-product gypsum, 10-20 parts of cement, 40-50 parts of water, 5-7 parts of composite alkaline activator, 2-3 parts of calcium sulfoaluminate, 7-10 parts of organosilicon resin modified steel fiber, 3-4 parts of water reducing agent, and 250-300 parts of crushed stone; The raw materials of the organosilicon resin modified steel fiber include hydrogen-containing organosilicon resin, polyborosiloxane and steel fiber in a mass ratio of 32:1.6:40-50.

2. The roadbed structure based on slag-gypsum-based cementitious materials according to claim 1, characterized in that: The preparation method of the organosilicon resin modified steel fiber is: S1: Dissolve hydrogenated silicone resin in xylene, add polyborosiloxane and platinum catalyst, charge with nitrogen at 80-90°C, react for 1-2 hours, raise the temperature to 150-180°C and react for 3-4 hours, then grind into powder after cooling to obtain modified silicone. The platinum catalyst content is 2.5-3% of the mass of polyborosiloxane. S2: Plasma treating the steel fiber for 3-5 min, washing, and drying to obtain modified steel fiber; S3: Using the modified steel fiber obtained in S2 as a receiving substrate, the modified silicone obtained in S1 is subjected to electrostatic spraying technology, and then dried at 60-70°C for 12-14h to obtain silicone resin modified steel fiber.

3. The roadbed structure based on slag-gypsum-based cementitious materials according to claim 2, characterized in that: The modified silicone is subjected to the following pretreatment before electrostatic spraying: The modified organosilicon and 5-aminotetrazole are uniformly mixed in a dimethyl sulfoxide solvent, triruthenium dodecacarbonyl is added, and the mixture is reacted at 120-150° C. for 24-26 hours. After the reaction is completed, the mixture is separated on a chromatography column to obtain a pretreated modified organosilicon. The mass ratio of the modified organosilicon, 5-aminotetrazole, and triruthenium dodecacarbonyl is 32:85-87:0.

32.

4. The roadbed structure based on slag-gypsum based cementitious materials according to claim 2, characterized in that: The steel fibers were pretreated as follows before plasma treatment: Under argon protection, the film was etched using a fiber laser beam at a wavelength of 1064 nm for 3-5 minutes, washed, and then dried.

5. The roadbed structure based on slag-gypsum based cementitious materials according to claim 1, characterized in that: The composite alkaline activator comprises calcium hydroxide and sodium silicate in a mass ratio of 1-1.5:1.2-1.

3.

6. The roadbed structure based on slag-gypsum based cementitious materials according to claim 1, characterized in that: 2-3 parts of carbon dioxide foam are also added to the slag-gypsum based gelling material.

7. The roadbed structure based on slag-gypsum based cementitious materials according to claim 6, characterized in that: The preparation method of the carbon dioxide foam is: S1: uniformly mixing polyoxyethylene alkyl alcohol amide and sodium lauryl sulfonate to prepare a liquid foaming agent; S2: placing the liquid foaming agent obtained in S1 into a foaming machine, introducing carbon dioxide at 33-35° C., and foaming for 20-30 minutes to obtain carbon dioxide foam, wherein the mass ratio of polyoxyethylene alkyl alcohol amide to sodium lauryl sulfate is 1:0.5-0.

7.

8. The construction process of the roadbed structure based on slag-gypsum-based cementitious materials according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Roadbed leveling: After removing the road surface rocks, compact the roadbed, upper embankment and lower embankment; S2: Raw material mixing: Mix the raw materials evenly according to the formula to prepare slag-gypsum based cementitious material, and add crushed stone to obtain a mixture; S3: Spreading, shaping, and rolling: Spread and shape the mixture obtained in S2, and roll it when the moisture content of the mixture is 1-2%; S4: Curing: After compaction is completed, watering and curing are carried out for 7-10 days.

9. The construction process of the roadbed structure based on slag-gypsum-based cementitious materials according to claim 8, characterized in that: In step S2, the slag-gypsum based cementitious material is prepared by the following steps: S1: drying, grinding and uniformly mixing slag and industrial by-product gypsum to prepare a mixture; S2: Cement, calcium sulfoaluminate and the mixture obtained in S1 are uniformly mixed, and after ball milling in a ball mill for 5-10 minutes, silicone resin-modified steel fiber is added, and a water-soluble water-reducing agent and a composite alkaline activator are added and continued to grind for 10-15 minutes to obtain a slag-gypsum-based cementitious material.

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