Solid waste aeolian sand mixed base material and preparation method thereof

Abstract

The invention relates to the technical field of road engineering materials, and particularly discloses a solid waste aeolian sand mixed base material and a preparation method thereof. The solid waste and aeolian sand mixed base material is composed of industrial solid waste, aeolian sand, cement and water. The mixing amount of the cement accounts for 0.5%-2.5% of the total mass of the aeolian sand and solid waste mixture; the mixing amount of the aeolian sand accounts for 20-80% of the total mass of the aeolian sand and solid waste mixture; the solid waste premix is a mixture of carbide slag, desulfurized gypsum and fly ash. According to the invention, low-quality carbide slag, desulfurized gypsum and fly ash are mainly used as raw materials, and the mechanical properties of the material are optimized by regulating and controlling the dosage ratio of the raw materials and utilizing a composite solid waste activity excitation and low-dosage cement coordinated modification technology, so that the material can meet the basic requirements of desert highway construction; the problems that according to an existing aeolian sand material curing technology, due to the fact that a large amount of additives are added, cost is high, and durability is poor are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of highway materials, and particularly relates to a solid waste aeolian sand mixed base course material and a preparation method thereof. Background Art

[0004] Some studies have shown that directly using cementitious materials with traditional strong hydration characteristics to consolidate aeolian sand results in significant road diseases and poor durability in the extremely arid desert environment. Therefore, the efficient improvement of aeolian sand has become the key to enhancing its application level and road performance.

[0005] Industrial solid waste, originating from production activities in industries such as industry and transportation, covers a large number of solid wastes generated in processes such as the mining, beneficiation, smelting, power generation, and chemical engineering of metals, energy, and non-metallic minerals. These wastes are mainly composed of compounds such as silicates, aluminates, sulfates, and carbonates, and have the characteristics of large output, wide distribution, diverse types, and significant environmental hazards. However, the recyclable substances and potential active components contained therein endow it with significant resource utilization potential.

[0006] In the field of road engineering, with the in-depth study of the road performance of bulk industrial solid waste, the ways of resource utilization of solid waste have been continuously expanded: it can be directly used for subgrade filling, or alkali-activated geopolymer cementitious materials can be prepared through activation technology. However, due to differences in material sources and production processes, some low-quality solid wastes with high impurity content have limited engineering application scenarios due to insufficient activity, high activation cost, and the need to add a large amount of auxiliary agents.

[0007] The aeolian sand subgrade material disclosed in patent application CN117754725A is mainly obtained by mixing 74% - 76% of aeolian sand, 6% - 8% of cement, 1.5% - 2% of nano material, 0.3% - 0.5% of polyvinyl alcohol, 0.4% - 0.8% of polymer emulsion, 0.5% - 1.2% of sodium silicate, and 11.5% - 17.3% of water. Among them, not only additives such as polyvinyl alcohol, polymer emulsion, and nano material are used, and cementitious materials are prepared by adding additives to improve the overall strength. However, a large amount of these gel materials are incorporated to consolidate aeolian sand, which not only significantly increases the initial investment, but also easily leads to an increase in the brittleness of the aeolian sand subgrade material and a decrease in the fatigue resistance in the extremely arid desert environment, ultimately resulting in poor durability. Summary of the Invention

[0008] In order to solve the problems that the existing aeolian sand subgrade material has a high cost and poor durability due to the addition of a large amount of additives, the purpose of the present invention is to provide a solid waste aeolian sand mixed base course material and a preparation method thereof.

[0009] To achieve the above object, the technical solution of the present invention is as follows.

[0010] The present invention provides a solid waste aeolian sand mixed base material, which includes solid waste aeolian sand mixture, cement and water; the dosage of cement accounts for 0.5% - 2.5% of the total mass of the solid waste aeolian sand mixture; the solid waste aeolian sand mixture is obtained by mixing aeolian sand and solid waste premix, and the dosage of aeolian sand accounts for 20% - 80% of the total mass of the solid waste aeolian sand mixture; the solid waste premix is a mixture of carbide slag, desulfurized gypsum and fly ash.

[0011] The present invention mainly uses low-quality carbide slag, desulfurized gypsum and fly ash as raw materials, regulates the dosage ratio of each raw material, and further adds a small amount of cement for modification, so that the obtained material can meet the basic requirements of desert highway construction, and solves the problems of high cost and poor durability caused by the addition of a large amount of additives in the existing aeolian sand materials.

[0012] The present invention uses common industrial solid wastes and aeolian sand to prepare a mixture, without using chemical activators. By increasing the dosage of industrial solid wastes, the active components contained in the solid waste materials can produce a certain degree of hydration reaction to cement and solidify aeolian sand particles. Among them, Ca(OH)2 contained in carbide slag can provide an alkaline environment; in an alkaline environment, fly ash can react with SiO2 and Al2O3 in aeolian sand to generate C-(A)-S-H gel, which can bond and solidify aeolian sand and fill pores to improve mechanical strength, and desulfurized gypsum can generate AFt in an alkaline environment to provide early strength. Fine-grained solid wastes also supplement the particle gradation of aeolian sand, improving cohesion and shear strength.

[0013] The present invention does not require complex activation treatment or the addition of extra alkali activators. By simple mixing, the solid waste aeolian sand mixed base material is prepared by mixing with aeolian sand in a way of increasing the dosage of industrial solid wastes. While meeting the strength requirements of the subbase, a low-dose cement is further added for reinforcement, thereby broadening the road application grade and level of the solid waste aeolian sand mixture, and providing key technical support for improving the mechanical properties of aeolian sand used in roads and the large-scale treatment and application of industrial solid wastes.

[0014] The present invention uses a solid waste aeolian sand mixed material with low stiffness and high toughness, which can effectively decompose industrial solid wastes and reduce road diseases, reduce the base stiffness through weak hydration bonding, improve the toughness of the material, and extend the service life, providing key technical support for desert highway construction and ensuring the safety, stability and sustainable development of the project.

[0015] Preferably, the dosage of the solid waste premix accounts for 30% - 80% of the total mass of the solid waste aeolian sand mixture.

[0016] Preferably, the solid waste aeolian sand mixture is obtained by mixing the following raw materials in mass percentages:

[0017] A: Aeolian sand 60%, desulfurized gypsum 5.7% - 20%, fly ash 6.7% - 20% and carbide slag 6.7% - 20%, totaling 100%. B: Aeolian sand 60%, desulfurized gypsum 13.3% - 20%, fly ash 6.7% - 13.3% and carbide slag 6.7% - 20%, totaling 100%.

[0018] Preferably, in the aeolian sand, the particle size less than 0.075mm does not exceed 10%, and 90% - 95% of the particle size is between 0.075mm and 0.25mm; the particle size of the solid waste premix is less than 0.075mm.

[0019] Preferably, in the carbide slag, the calcium oxide content ≥ 77%; in the fly ash, the total oxide content ≥ 56%; in the desulfurized gypsum, the total calcium sulfate content ≥ 76%.

[0020] Preferably, the water content accounts for 15% of the total mass of the solid waste aeolian sand mixture.

[0021] On the other hand, the present invention provides a preparation method of a solid waste aeolian sand mixed base material, including the following steps:

[0022] Mix the carbide slag, fly ash, desulfurized gypsum and aeolian sand evenly to obtain a solid waste aeolian sand mixture; mix the solid waste aeolian sand mixture, cement and water evenly to obtain a solid waste aeolian sand mixed base material.

[0023] In the present invention, before preparing the solid waste aeolian sand mixture, it is necessary to dry and grind the solid waste materials to ensure a certain fineness, so that it can be directly mixed and compacted for use without adding modifiers, and has certain mechanical properties, which can meet the strength requirements of the subbase, so that it can be widely applied to desert highway construction on the basis of low cost and environmental protection.

[0024] The beneficial effects of the present invention:

[0025] 1. The present invention mainly uses carbide slag, desulfurized gypsum and fly ash as raw materials, adjusts the dosage ratio of each raw material, and further adds a low dosage of cement for modification, so that the obtained material can meet the basic requirements of desert highway construction, and has significant economic benefits, solving the problems of high cost and poor durability caused by the addition of a large amount of additives in the existing aeolian sand subgrade materials.

[0026] 2. The present invention mainly uses a large amount of industrial solid waste carbide slag, desulfurized gypsum and fly ash stored around the desert to prepare industrial solid waste aeolian sand mixtures with different ratios. Without using chemical activators, by increasing the content of industrial solid waste, the active components contained in the solid waste materials can produce sufficient hydration reaction to cement and solidify the aeolian sand particles.

[0027] 3. The present invention utilizes a solid waste aeolian sand mixed material with low stiffness and high toughness, which can effectively decompose industrial solid waste, reduce road diseases, and extend the service life, providing key technical support for the construction of desert highways and ensuring the safety, stability, and sustainable development of the project. Description of the Drawings

[0028] Figure 1 It is the particle size distribution and compaction characteristics diagram of aeolian sand. Among them, (a) is the particle size distribution diagram of aeolian sand; (b) is the compaction characteristics diagram of aeolian sand.

[0029] Figure 2 It is the micrograph of aeolian sand, carbide slag, desulfurized gypsum, and fly ash. Among them, (a1) and (a2) are the micrographs of aeolian sand at different magnifications; (b1) and (b2) are the micrographs of carbide slag at different magnifications; (c1) and (c2) are the micrographs of desulfurized gypsum at different magnifications; (d1) and (d2) are the micrographs of fly ash at different magnifications.

[0030] Figure 3 It is the energy dispersive X-ray spectroscopy diagram of fly ash, desulfurized gypsum, and carbide slag.

[0031] Figure 4 It is the Fourier transform infrared spectroscopy diagram of fly ash, desulfurized gypsum, and carbide slag.

[0032] Figure 5 It is the comparison diagram of the 7-day unconfined compressive strength of the cylindrical test block prepared in Example 1 after immersion and without immersion.

[0033] Figure 6 It is the broken line diagram of the 7-day unconfined compressive strength of the cylindrical test block prepared in Example 2 after immersion and without immersion varying with the dosage of the solid waste premix.

[0034] Figure 7 It is the broken line diagram of the 7-day unconfined compressive strength of the cylindrical test block prepared in Example 3 after immersion varying with the dosage of cement.

[0035] Figure 8 It is the broken line diagram of the unconfined compressive strength of the cylindrical test block prepared in Example 4 after immersion varying with the curing age.

[0036] Figure 9 It is the broken line diagram of the splitting strength of the cylindrical test block prepared in Example 5 after immersion varying with the curing age.

[0037] Figure 10 It is the broken line diagram of the compressive resilience modulus of the cylindrical test block prepared in Example 5 after immersion varying with the curing age.

[0038] Figure 11 It is a line graph showing the change in the flexural tensile strength of the rectangular small beam test block prepared in Example 6 after immersion in water as a function of the curing age. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0040] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0041] At present, aeolian sand is mainly used as roadbed material in highway construction. When used as base material, a high amount of cement is usually used to stabilize the aeolian sand, wherein the cement content is about 10% to 15%. However, the use of a large amount of hydrated gel materials often leads to significant road diseases and poor durability in the extremely dry environment of the desert.

[0042] Therefore, the present invention uses three solid waste materials, namely carbide slag, desulfurized gypsum and fly ash, as the main materials for road construction, which play the role of improving grading and physical filling, and can also provide active ingredients to produce hydration reaction to cement and solidify aeolian sand. By reducing the cement content and adjusting the solid waste ratio, the application of solid waste and aeolian sand in road engineering can be realized.

[0043] The present invention mainly utilizes the synergistic effect of various solid waste materials in an alkaline environment to achieve the solidification of aeolian sand and the improvement of its mechanical properties through chemical reaction and physical filling mechanism. Among them, Ca(OH)2 in carbide slag provides an alkaline environment.

[0044] In an alkaline environment, fly ash reacts with SiO2 and Al2O3 in aeolian sand to form C-(A)-ASH gel. The chemical reaction formula is: SiO2+Al2O3+Ca(OH)2+H2O→C-(A)-SH gel. The generated C-(A)-ASH gel can be used to connect and solidify aeolian sand particles and fill pores, thereby improving the mechanical strength of the resulting material.

[0045] Desulfurized gypsum generates calcium sulfonate in an alkaline environment to provide early strength. The chemical reaction formula is: 3CaO+Al2O3+3CaSO4+32H2O→AFt (calcium sulfonate). The early strength of the obtained material is further enhanced by the generation of AFt.

[0046] The technical solution of the present invention is further described below through specific embodiments.

[0047] In the following embodiments, unless otherwise specified, the methods are all conventional methods; the reagents and materials, unless otherwise specified, can all be obtained commercially.

[0048] In the following embodiments, the cement is 42.5 grade ordinary Portland cement.

[0049] In the following embodiments, the aeolian sand comes from Aksu area around the Taklimakan Desert. The organic impurities in the aeolian sand should be removed. Among them, the particle size less than 0.075mm does not exceed 10%, and 90% - 95% of the particle size is between 0.075mm and 0.25mm. The moisture content of the aeolian sand needs to be tested before use. When adding water for mixing, the contained moisture should be calculated and deducted. The particle gradation and compaction characteristics of the aeolian sand are shown in Figure 1 .

[0050] From Figure 1 (a) figure of can be seen that the main particle size of the aeolian sand is between 0.075mm and 0.25mm, accounting for 72.69%. It contains 7.21% of fine particles less than 0.075mm, and the mass ratio of particles between 0.25mm and 0.5mm is 18.43%.

[0051] The compaction characteristic is the change law of dry density under different water contents and compaction work conditions. From Figure 1 (b) figure of can be seen that the maximum dry density of the aeolian sand is 1.774g / cm 3 , and the corresponding optimum moisture content is 10%.

[0052] In the following embodiments, carbide slag, desulfurized gypsum and fly ash are respectively three kinds of low-quality industrial solid waste materials from Aksu area around the Taklimakan Desert. The micrographs of the solid waste materials are shown in Figure 2 .

[0053] From Figure 2 it can be seen that the aeolian sand particles have irregular shapes, relatively concentrated particle size distribution, and many edges and corners on the surface, indicating that the wind erosion effect is small and spherical particles are not formed; then magnifying to 5000 times, it can be seen that the micro surface is relatively flat and there are small particle debris attached.

[0054] Most of the carbide slag particles are flaky, mainly fine particles, and a small amount of coarser particles are distributed among them; magnifying to 5000 times, it can be seen that the particle surface is rough and the overall morphology is relatively loose, which is formed by the aggregation of fine flaky components.

[0055] The desulfurized gypsum particles are coarser and have irregular shapes. Magnifying to 5000 times, it can be seen that the particle surface is rough and there are pores all over the surface, with relatively large hygroscopicity.

[0056] Fly ash particles are mainly spherical, with fewer large-sized particles and more small-sized particles. After magnifying 5000 times, it can be seen that the surface of fly ash is relatively smooth, and there are fine particles and needle-shaped crystals adsorbed on its surface.

[0057] Energy-dispersive X-ray spectroscopy diagrams of fly ash, desulfurized gypsum, and carbide slag are shown in Figure 3 .

[0058] It can be seen from Figure 3 that the main element component in carbide slag is Ca, and its peak characteristics are the most significant, indicating that its component content is the highest. Secondly, the peaks of O, Si, Al, and C appear, indicating that its main chemical components are CaO, SiO2, and Al2O3.

[0059] For desulfurized gypsum, the most significant peaks are for the elements Ca and S, followed by the element O, indicating that its main component is CaSO4. Secondly, the low peaks of Si, Al, Mg, and C also appear, indicating that it contains a small amount of oxides such as SiO2, Al2O3, and MgO.

[0060] For fly ash, the most significant peak is Si, followed by Al and O, indicating that its main chemical components are SiO2 and Al2O3. Secondly, the low peaks of Ca, K, Na, Mg, and C appear, indicating that fly ash contains a small amount of oxides such as CaO, K2O, Na2O, and MgO.

[0061] In summary, it can be seen that the peak of C appears in all three low-quality industrial solid waste materials, indicating that they contain carbon-containing organic matter or unburned elemental carbon. Based on this discovery, the present invention precisely adjusts the ratio of each component to ensure that the prepared specimen can achieve the required appropriate mechanical strength.

[0062] During the preparation of the solid waste aeolian sand mixed base course material, the particle size of the three low-quality industrial solid waste materials should be less than 0.075 mm, that is, ground to less than 200 mesh, without obvious particle feeling. The chemical component contents of the three industrial solid waste materials are shown in Table 1.

[0063] Table 1 Chemical component contents of industrial solid waste materials

[0064] Content / % CaO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[SO3]]> MgO <![CDATA[Fe2O3]]> <![CDATA[Na2O]]> <![CDATA[K2O]]> Cl F Others Total Calcium carbide slag 77.10 3.87 1.62 0.65 0.54 0.39 0.19 0.14 0.14 - 15.36 100 Fly ash 5.05 29.50 12.00 0.51 1.09 5.22 0.57 2.06 - - 44.00 100 Desulfurized gypsum 36.00 2.14 0.86 40.00 0.35 0.34 0.13 0.14 - 0.58 19.46 100

[0065] Note: "-" indicates no data.

[0066] As shown in the results of Table 1, the content of the main active ingredient CaO in carbide slag is relatively high, and the content of 15.36% non-oxides hinders the hydration reaction and its activity is low. The main component of desulfurized gypsum is CaSO4·0.5H2O, and the total component detected in the form of oxides accounts for 76%, and it also contains 19.46% organic matter, with low activity. The total content of the main potentially active components SiO2 and Al2O3 in fly ash is 41.50%, and its impurity content is as high as 44.00%, mainly unburned carbon and C-H organic compounds. These high contents of impurities result in poor activity performance when solidifying aeolian sand. Therefore, when applying in practice, low-dose cement is considered for reinforcement.

[0067] Based on the above analysis, all three low-quality industrial solid waste materials contain a large amount of non-oxide impurities and have low activity. Therefore, to ensure the minimum strength requirement, the calcium oxide content in carbide slag should be ≥77%, the total content of oxides such as Si, Al, Ca, Mg, Fe, K, Na in fly ash should be ≥56%, and the total content of calcium sulfate in desulfurized gypsum should be ≥76%.

[0068] The Fourier transform infrared spectra of fly ash, desulfurized gypsum and carbide slag are shown in Figure 4 .

[0069] It can be seen from Figure 4 that the positions where the main peaks of the three low-quality industrial solid waste materials appear are different. Among them, the peak of fly ash is weak. The three relatively significant peaks represent Al2O3 and SiO2 respectively, and the peaks of the remaining molecular structures are weak, and the overall curve is relatively flat. The peak of desulfurized gypsum is the most significant, among which Al-O, Si-O, S-O and C-H bonds are more significant. The most significant peak in carbide slag is Al-O, while the peak of Ca-O bond is weak and is generally difficult to detect. This shows that the three low-quality industrial solid waste materials contain active chemical bonds, can produce hydration reactions, produce aluminosilicate gels and carbonates, so as to achieve the effect of solidifying and stabilizing aeolian sand.

[0070] Example 1

[0071] A solid waste aeolian sand mixed base material includes a solid waste aeolian sand mixture and water. Among them, the dosage of water accounts for 15% of the total mass of the solid waste aeolian sand mixture; the solid waste aeolian sand mixture is obtained by mixing aeolian sand, carbide slag, desulfurized gypsum and fly ash; among them, the mass ratios of the solid materials in the solid waste aeolian sand mixture are shown in Table 2.

[0072] Table 2 Mass ratios of the solid materials in the solid waste aeolian sand mixture / %

[0073]

[0074]

[0075] Preparation method of solid waste aeolian sand mixed base material, comprising the following steps:

[0076] S1. Weigh each raw material according to the above raw material ratio, add dry powder of carbide slag, fly ash and desulfurization gypsum into a stirrer and stir evenly to obtain a solid waste premix; place it in a dry place for standby.

[0077] S2. Add the solid waste premix and aeolian sand into a stirrer according to the set dosage ratio and stir evenly to obtain a solid waste aeolian sand mixture.

[0078] S3. Add water accounting for 15% of the total mass of the solid waste aeolian sand mixture into the solid waste aeolian sand mixture, mix evenly, and obtain the solid waste aeolian sand mixed base material.

[0079] Add the mixed solid waste aeolian sand mixed base material into a mold and press it statically to form. The pressure is 0.5 MPa, and a cylindrical test block with φ50mm×h50mm is prepared. The compaction degree is 98%. The same batch of wet materials should be used within 30 minutes. After stabilizing for 5 minutes, demold, seal it with a plastic bag after demolding, move it into a curing box for curing, and test the unconfined compressive strength after 7 days of immersion and without immersion for 7 days. The results are shown in Figure 5 .

[0080] From Figure 5 the results, it can be seen that increasing the dosage of fly ash will lead to a decrease in strength, and the increase in non-oxides in fly ash will hinder the hydration reaction; increasing the dosage of desulfurization gypsum will significantly increase the strength, and desulfurization gypsum will generate ettringite to increase the strength; increasing the dosage of carbide slag will increase the strength, but due to the low quality of carbide slag, the provided alkaline ions are limited, so the increase in strength is relatively small.

[0081] Example 2

[0082] A solid waste aeolian sand mixed base material, comprising a solid waste aeolian sand mixture and water. Among them, the dosage of water accounts for 15% of the total mass of the solid waste aeolian sand mixture; the solid waste aeolian sand mixture is obtained by mixing aeolian sand, carbide slag, desulfurization gypsum and fly ash; among them, according to the mass ratio of the three solid waste materials of carbide slag, fly ash and desulfurization gypsum, the solid waste aeolian sand mixture is divided into two groups, and the specific raw material ratios are as follows:

[0083] In group A, the mass ratio of carbide slag, fly ash and desulfurization gypsum is 3:1:2. The dosage of the solid waste premix obtained by mixing the three solid waste materials accounts for 20%, 30%, 40%, 50%, 60%, 70% or 80% of the mass of the solid waste aeolian sand mixture.

[0084] In Group B, the mass ratio of carbide slag, fly ash and desulfurized gypsum is 1:2:3. The mass percentage of the solid waste premix obtained by mixing the three solid waste materials in the solid waste aeolian sand mixture is 20%, 30%, 40%, 50%, 60%, 70% or 80%.

[0085] Table 3 Feeding conditions for different dosages of solid waste premix

[0086] Group number of Group A Dosage of solid waste premix Group number of Group B Dosage of solid waste premix A1 20％ B1 20％ A2 30％ B2 30％ A3 40％ B3 40％ A4 50％ B4 50％ A5 60％ B5 60％ A6 70％ B6 70％ A7 80％ B7 80％

[0087] A preparation method for a solid waste aeolian sand mixed base material, comprising the following steps:

[0088] S1. Weigh each raw material according to the above raw material ratio, add the dry powder of carbide slag, fly ash and desulfurized gypsum into a stirrer and stir evenly to obtain a solid waste premix; place it in a dry place for standby.

[0089] S2. Add the solid waste premix and aeolian sand into a stirrer according to the set dosage ratio and stir evenly to obtain a solid waste aeolian sand mixture.

[0090] S3. Add water accounting for 15% of the total mass of the solid waste aeolian sand mixture to the solid waste aeolian sand mixture, and after mixing evenly, obtain the solid waste aeolian sand mixed base material.

[0091] Add the mixed solid waste aeolian sand mixed base material into a cylindrical mold with φ50mm×h50mm and press it statically. The pressure is 0.5MPa to prepare a cylindrical test block, and the compaction degree is 98%. The same batch of wet materials should be used within 30 minutes. After stabilizing for 5 minutes, demold, seal it with a plastic bag and transfer it to a curing box for curing. Test the unconfined compressive strength after 7 days of immersion and 7 days without immersion. The results are shown in Figure 6 .

[0092] From Figure 6 the results, it can be seen that for the solid waste aeolian sand mixtures with the mixing ratios of Group A and Group B, as the dosage of the solid waste premix increases, the 7-day unconfined compressive strength of the test samples shows a trend of first increasing and then decreasing. Among them, when the dosage of the solid waste premix is greater than 50%, the 7-day unconfined compressive strength of the test samples in Group A and Group B is greater than 3MPa; when the dosage of the solid waste premix is 70%, the 7-day unconfined compressive strength of the test samples in Group A and Group B without immersion reaches the maximum, up to more than 6MPa.

[0093] Based on the above analysis, it can be known that after the dosage of the solid waste premix ≥ 30%, the strength of the solid waste aeolian sand mixture can meet the strength requirements of the road subbase.

[0094] Example 3

[0095] A solid waste aeolian sand mixed base material, comprising a solid waste aeolian sand mixture, cement and water. Among them, the water content accounts for 15% of the total mass of the solid waste aeolian sand mixture; the cement content accounts for 0%, 0.5%, 1.0%, 1.5%, 2.0% or 2.5% of the total mass of the solid waste aeolian sand mixture. The solid waste aeolian sand mixture is obtained by mixing aeolian sand, carbide slag, desulfurized gypsum and fly ash. Among them, according to the mass ratio of the three solid waste materials, the solid waste aeolian sand mixture is divided into two groups. In terms of mass percentage, the specific raw material ratios are as follows:

[0096] In Group A of the solid waste aeolian sand mixture, carbide slag is 20%, fly ash is 6.7%, desulfurized gypsum is 13.3% and aeolian sand is 60%, totaling 100%.

[0097] In Group B of the solid waste aeolian sand mixture, carbide slag is 6.7%, fly ash is 13.3%, desulfurized gypsum is 20% and aeolian sand is 60%, totaling 100%.

[0098] Table 4 Feeding conditions for different cement contents

[0099] Group number of Group A Dosage of cement Group number of Group B Dosage of cement A8 0％ B8 0％ A9 0.5％ B9 0.5％ A10 1.0％ B10 1.0％ A11 1.5％ B11 1.5％ A12 2.0％ B12 2.0％ A13 2.5％ B13 2.5％

[0100] The preparation method of the solid waste aeolian sand mixed base material includes the following steps:

[0101] S1. Weigh each raw material according to the above raw material ratio, add the dry powder of carbide slag, fly ash and desulfurized gypsum into a stirrer and stir evenly to obtain a solid waste premix; place it in a dry place for standby.

[0102] S2. Add the solid waste premix and aeolian sand into a stirrer according to the set dosage ratio and stir evenly to obtain a solid waste aeolian sand mixture.

[0103] S3. Add different dosages of cement to the solid waste aeolian sand mixture prepared according to the ratio of Group A for reinforcement, and then add water accounting for 15% of the total mass of the solid waste aeolian sand mixture, and mix evenly to obtain the solid waste aeolian sand mixed base materials of Group A8 - Group A13.

[0104] Add different dosages of cement to the solid waste aeolian sand mixture prepared according to the ratio of Group B for reinforcement, and then add water accounting for 15% of the total mass of the solid waste aeolian sand mixture, and mix evenly to obtain the solid waste aeolian sand mixed base materials of Group B8 - Group B13.

[0105] The solid waste aeolian sand mixture base course materials after mixing each group are added into a cylindrical mold and statically pressed into shape under a pressure of 0.5 MPa to prepare cylindrical test blocks with a diameter of φ50 mm and a height of h50 mm, and the compaction degree is 98%. The wet materials of the same batch should be used within 30 min, demolded after a stable pressure of 5 min, sealed with a plastic bag and then transferred to a standard curing box for curing. Soak in water on the last day and test the unconfined compressive strength after 7 days of soaking. The results are shown in Figure 7 .

[0106] From Figure 7 the results, it can be seen that after the solid waste aeolian sand mixtures with two different ratios are reinforced with different dosages of cement, the 7-day unconfined compressive strength increases to varying degrees. The 7-day unconfined compressive strength of Group A shows a trend of first increasing and then decreasing with the increase of the cement dosage. When the cement dosage is greater than 1.5%, the 7-day unconfined compressive strength exceeds 3 MPa. The 7-day unconfined compressive strength of Group B continuously increases with the increase of the cement dosage, and when the cement dosage is greater than 1.0%, the 7-day unconfined compressive strength exceeds 3 MPa.

[0107] Thus, it can be seen that when the dosage of the solid waste premix accounts for 40% of the mass of the solid waste aeolian sand mixture and the cement dosage is greater than 1.5%, the 7-day unconfined compressive strength of the cylindrical test blocks prepared from the two groups of solid waste aeolian sand mixture base course materials can meet the strength requirements of the road base.

[0108] Example 4

[0109] A kind of solid waste aeolian sand mixture base course material, comprising a solid waste aeolian sand mixture, cement and water. Among them, the dosage of water accounts for 15% of the total mass of the solid waste aeolian sand mixture; the solid waste aeolian sand mixture is obtained by mixing aeolian sand, carbide slag, desulfurized gypsum and fly ash; among them, according to the mass ratio of the three solid waste materials of carbide slag, fly ash and desulfurized gypsum, the solid waste aeolian sand mixture is divided into two groups. In terms of mass percentage, the specific raw material ratios are as follows:

[0110] In the solid waste aeolian sand mixture of Group A, carbide slag is 20%, fly ash is 6.7%, desulfurized gypsum is 13.3% and aeolian sand is 60%, totaling 100%.

[0111] In the solid waste aeolian sand mixture of Group B, carbide slag is 6.7%, fly ash is 13.3%, desulfurized gypsum is 20% and aeolian sand is 60%, totaling 100%.

[0112] In addition, to reinforce the solid waste aeolian sand mixture of Group A by adding cement accounting for 2.5% of the total mass of the solid waste aeolian sand mixture, it is used as Group AC; to reinforce the solid waste aeolian sand mixture of Group B by adding cement accounting for 2.5% of the total mass of the solid waste aeolian sand mixture, it is used as Group BC.

[0113] Table 5 Feeding conditions of different groups

[0114] Group A Group B Group AC Group BC Dosage of cement 0 0 2.5％ 2.5％

[0115] Preparation method of solid waste aeolian sand mixed base material, comprising the following steps:

[0116] S1. Weigh each raw material according to the above raw material ratio, add dry powder carbide slag, fly ash and desulfurization gypsum into a stirrer and stir evenly to obtain a solid waste premix; place it in a dry place for standby.

[0117] S2. Add the solid waste premix and aeolian sand into a stirrer according to the set dosage ratio and stir evenly to obtain a solid waste aeolian sand mixture.

[0118] S3. Add water accounting for 15% of the total mass of the solid waste aeolian sand mixture to the solid waste aeolian sand mixture, mix evenly to obtain the solid waste aeolian sand mixed base material.

[0119] Add cement to groups A and B for reinforcement, then add water accounting for 15% of the total mass of the solid waste aeolian sand mixture, mix evenly to obtain groups AC and BC.

[0120] Add the mixed solid waste aeolian sand mixed base material of each group into a cylindrical mold and press it statically. The pressure is 0.5 MPa to prepare a cylindrical test block with φ50mm×h50mm, and the compactness is 98%. The same batch of wet materials should be used within 30 minutes, demold after stabilizing for 5 minutes, seal it with a plastic bag and transfer it to a standard curing box for curing. Immerse it in water on the last day of the test age, and respectively test the unconfined compressive strength after 3d, 7d, 14d, 28d, 60d and 90d. The results are shown in Figure 8 .

[0121] From Figure 8 the results, it can be seen that the unconfined compressive strength of the cylindrical test blocks prepared under the 4 ratios all increases with the increase of the curing age, and after being reinforced with cement, the unconfined compressive strength increases significantly. Among them, the unconfined compressive strength of groups A and AC within the curing age of 3d to 90d is 2MPa to 5MPa, and the unconfined compressive strength of groups B and BC within the curing age of 3d to 90d is 2MPa to 9MPa. The results show that the ability of the solid waste aeolian sand mixture provided by the embodiments of the present invention to continuously increase the unconfined compressive strength with the curing age can meet the long-term use requirements of the road base.

[0122] Example 5

[0123] A solid waste aeolian sand mixed base material, comprising a solid waste aeolian sand mixture, cement and water. Among them, the dosage of water accounts for 15% of the total mass of the solid waste aeolian sand mixture; the solid waste aeolian sand mixture is obtained by mixing aeolian sand, carbide slag, desulfurized gypsum and fly ash. Among them, according to the mass ratio of the three solid waste materials of carbide slag, fly ash and desulfurized gypsum, the solid waste aeolian sand mixture is divided into two groups. In terms of mass percentage, the specific raw material ratios are as follows:

[0124] In the Group A solid waste aeolian sand mixture, carbide slag is 20%, fly ash is 6.7%, desulfurized gypsum is 13.3% and aeolian sand is 60%, with a total of 100%.

[0125] In the Group B solid waste aeolian sand mixture, carbide slag is 6.7%, fly ash is 13.3%, desulfurized gypsum is 20% and aeolian sand is 60%, with a total of 100%.

[0126] In addition, 2.5% of the total mass of the solid waste aeolian sand mixture is added with cement to reinforce the Group A solid waste aeolian sand mixture, which is used as the AC group; 2.5% of the total mass of the solid waste aeolian sand mixture is added with cement to reinforce the Group B solid waste aeolian sand mixture, which is used as the BC group. The feeding conditions of different groups are specifically shown in Table 5.

[0127] The preparation method of the solid waste aeolian sand mixed base material includes the following steps:

[0128] S1. Weigh each raw material according to the above raw material ratio, add the dry powder of carbide slag, fly ash and desulfurized gypsum into a stirrer and stir evenly to obtain a solid waste premix; place it in a dry place for standby.

[0129] S2. Add the solid waste premix and aeolian sand into a stirrer according to the set dosage ratio and stir evenly to obtain a solid waste aeolian sand mixture.

[0130] S3. Add 15% of the total mass of the solid waste aeolian sand mixture of water, mix evenly to obtain a solid waste aeolian sand mixed base material.

[0131] Add the solid waste aeolian sand mixed base material after mixing each group into a cylindrical mold with φ100mm×h100mm and press it statically to form. The pressure is 0.5MPa to prepare a cylindrical test block, and the compactness is 98%. The same batch of wet materials should be used within 30 minutes, demould after stabilizing for 5 minutes, seal with a plastic bag, move it into a standard curing box for curing, soak it in water on the last day of the test age, and respectively test the splitting strength after 7d, 28d, 60d and 90d and the compressive resilience modulus after 7d, 28d and 90d. The results are shown in Figure 9 and Figure 10 .

[0132] From Figure 9It can be seen from the results that the splitting strengths of the cylindrical specimens prepared under the four ratios all increase with the increase of the curing age, and after being reinforced with cement, the splitting strength increases significantly. Among them, the splitting strengths of Group A and Group AC within the curing age of 7d - 90d are 0.14MPa - 0.47MPa, and the splitting strengths of Group B and Group BC within the curing age of 7d - 90d are 0.17MPa - 0.93MPa. The results show that the splitting tensile strength of the cylindrical specimens prepared with the solid waste aeolian sand mixed base material provided by the embodiments of the present invention can continuously increase with the increase of the curing age, and has a certain crack and disease resistance ability.

[0133] It can be seen from Figure 10 the results that the compressive resilience moduli of the four ratios all increase with the increase of the curing age, and after being reinforced with cement, the compressive resilience modulus increases significantly. Among them, the compressive resilience moduli of Group A and Group AC within the curing age of 7d - 90d are 454MPa - 1808MPa, and the compressive resilience moduli of Group B and Group BC within the curing age of 7d - 90d are 1113MPa - 3375MPa. The results show that the compressive resilience modulus of the solid waste aeolian sand mixed base material provided by the embodiments of the present invention can continuously increase with the increase of the curing age, and has a certain stability and durability when bearing traffic loads.

[0134] Example 6

[0135] A solid waste aeolian sand mixed base material, comprising a solid waste aeolian sand mixture, cement and water. Among them, the dosage of water accounts for 15% of the total mass of the solid waste aeolian sand mixture; the solid waste aeolian sand mixture is obtained by mixing aeolian sand, carbide slag, desulfurized gypsum and fly ash; among them, according to the mass ratio of the three solid waste materials of carbide slag, fly ash and desulfurized gypsum, the solid waste aeolian sand mixture is divided into two groups. In terms of mass percentage, the specific raw material ratios are as follows:

[0136] In the solid waste aeolian sand mixture of Group A, carbide slag is 20%, fly ash is 6.7%, desulfurized gypsum is 13.3% and aeolian sand is 60%, totaling 100%.

[0137] In the solid waste aeolian sand mixture of Group B, carbide slag is 6.7%, fly ash is 13.3%, desulfurized gypsum is 20% and aeolian sand is 60%, totaling 100%.

[0138] In addition, 2.5% of the total mass of the solid waste aeolian sand mixture in Group A is added with cement for reinforcement to form Group AC; 2.5% of the total mass of the solid waste aeolian sand mixture in Group B is added with cement for reinforcement to form Group BC.

[0139] The preparation method of the solid waste aeolian sand mixed base material includes the following steps:

[0140] S1. Weigh each raw material according to the above raw material ratio. Add dry powdered carbide slag, fly ash, and desulfurized gypsum into a stirrer and stir evenly to obtain a solid waste premix. Place it in a dry place for standby.

[0141] S2. Add the solid waste premix and aeolian sand into a stirrer according to the set dosage ratio and stir evenly to obtain a solid waste - aeolian sand mixture.

[0142] S3. Add 15% water to the solid waste - aeolian sand mixture and mix evenly to obtain a solid waste - aeolian sand mixed base material.

[0143] Add each group of materials into a 100mm×50mm×50mm cuboid mold and press - mold statically at a pressure of 0.5MPa to prepare 100mm×50mm×50mm cuboid beam specimens with a compactness of 98%. The same - batch wet materials should be used within 30 minutes. After stabilizing for 5 minutes, demold. After demolding, seal with a plastic bag and transfer it to a standard curing box for curing. Immerse it in water for one day before the test age, and test the flexural tensile strength at 7d, 28d, and 90d respectively. The results are shown in Figure 11 .

[0144] From Figure 11 the results, it can be seen that the flexural tensile strengths of the four ratios all increase with the increase of the curing age, and after cement reinforcement, the flexural tensile strength increases significantly. Among them, the flexural tensile strengths of Group A and Group AC within the curing age of 7d - 90d are 0.13MPa - 0.61MPa, and the flexural tensile strengths of Group B and Group BC within the curing age of 7d - 90d are 0.50MPa - 2.58MPa. The results show that the flexural tensile strength of the solid waste - aeolian sand mixed base material provided by the embodiments of the present invention can continuously increase with the increase of the curing age and has the ability to resist damage under the action of bending load.

[0145] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A solid waste and aeolian sand mixed base material, characterized in that, It includes solid waste aeolian sand mixture, cement and water; The dosage of cement accounts for 0.5% - 2.5% of the total mass of the solid waste aeolian sand mixture; The solid waste aeolian sand mixture is obtained by mixing aeolian sand and solid waste premix. The dosage of aeolian sand accounts for 20% - 80% of the total mass of the solid waste aeolian sand mixture; The solid waste premix is a mixture of carbide slag, desulfurized gypsum and fly ash.

2. The solid waste aeolian sand mixed base course material according to claim 1, wherein The dosage of the solid waste premix accounts for 30% - 80% of the total mass of the solid waste aeolian sand mixture.

3. The solid waste aeolian sand mixed base material according to claim 1, characterized in that, The solid waste aeolian sand mixture is obtained by mixing the following raw materials in mass percentages: Aeolian sand 60%, desulfurized gypsum 5.7% - 20%, fly ash 6.7% - 20% and carbide slag 6.7% - 20%, totaling 100%.

4. The solid waste aeolian sand mixed base material according to claim 3, characterized in that, The solid waste aeolian sand mixture is obtained by mixing the following raw materials in mass percentages: Aeolian sand 60%, desulfurized gypsum 13.3% - 20%, fly ash 6.7% - 13.3% and carbide slag 6.7% - 20%, totaling 100%.

5. The solid waste and aeolian sand mixed base course material according to claim 1, wherein In the aeolian sand, the particle size less than 0.075mm does not exceed 10%, and 90% - 95% of the particle size is between 0.075mm and 0.25mm; The particle size of the solid waste premix is less than 0.075mm.

6. The solid waste aeolian sand mixed base course material according to claim 1, characterized in that, In the carbide slag, the calcium oxide content ≥ 77%; In the fly ash, the total oxide content ≥ 56%; In the desulfurized gypsum, the total calcium sulfate content ≥ 76%.

7. The solid waste aeolian sand mixed base material according to claim 1, characterized in that The dosage of water accounts for 15% of the total mass of the solid waste aeolian sand mixture.

8. A preparation method of the solid waste aeolian sand mixed base course material according to any one of claims 1 to 7, characterized in that, It includes the following steps: Mix carbide slag, fly ash, desulfurized gypsum and aeolian sand evenly to obtain a solid waste aeolian sand mixture; mix the solid waste aeolian sand mixture, cement and water evenly to obtain a solid waste aeolian sand mixed base material.

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