Application of high-free-calcium high-belite calcium sulphoaluminate clinker in preparation of high-strength binder stabilized macadam material

Abstract

The invention belongs to the technical field of building materials, and particularly discloses application of high-free-calcium and high-belite calcium sulphoaluminate clinker in preparation of a high-strength binder stabilized macadam material. According to the low-carbon waste-utilizing high-strength binder, the gypsum and the granulated blast-furnace slag powder are used as main raw materials, the specially designed clinker is doped, so that dihydrate gypsum crystals formed by externally doping the gypsum are doubly and compactly coated by AFt microcrystals and C-(A)-S-H gel, even under the condition that the mixing amount of the gypsum is relatively high, the dihydrate gypsum which is easily dissolved in water can be prevented from being dissolved in water, and the low-carbon waste-utilizing high-strength binder can be used for preparing the high-strength binder. The porosity of the high-strength binder stabilized macadam material is gradually reduced along with gradual densification of the microstructure, so that the problems of poor water resistance, great reduction of strength and poor freeze-thaw resistance of gypsum materials caused by high solubility of dihydrate gypsum are solved, and the unconfined compressive strength and durability of the high-strength binder stabilized macadam material are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, and in particular relates to the application of a high-free-calcium, high-belite calcium sulfoaluminate clinker in the preparation of high-strength binder stabilized crushed stone materials. Background Technology

[0002] Inorganic binder stabilized materials refer to road base or subbase materials with certain strength and stability, formed by mixing inorganic binders (such as cement, lime, and other inorganic cementitious materials) with aggregates and an appropriate amount of water, followed by mixing, compaction, and curing. Inorganic binder stabilized materials are widely used in highway and municipal road engineering. Their main functions are to bear vehicle loads, transfer stress, and provide solid support for the surface layer. Their performance directly affects the strength, stability, and durability of the pavement structure.

[0003] The performance of inorganic binder-stabilized materials is closely related to the inorganic binder, which is typically cement. When cement is mixed with water, a hydration reaction occurs, producing products such as calcium hydroxide, calcium silicate hydrate (CSH), and calcium aluminate hydrate. These hydration products gradually fill the pores between material particles, binding the dispersed aggregate particles together. As the hydration reaction continues, the material hardens, forming a rigid skeleton and ultimately a structurally sound whole with a certain strength. Because cement, commonly used in inorganic binder-stabilized materials, has a high carbon emission rate, this results in high carbon emissions and a significant environmental impact.

[0004] Industrial by-product gypsum is a solid waste mainly composed of calcium sulfate, generated during industrial production. It primarily originates from the chemical, power, and metallurgical industries and is one of the largest sources of industrial waste in my country. Gypsum is also a commonly used cementitious material, possessing advantages such as low carbon emissions, rapid hardening, and low shrinkage. However, its poor water resistance and low strength fail to meet the requirements of highway engineering. Therefore, there is an urgent need to develop a high-strength binder-stabilized crushed stone material with gypsum as the main component. This would not only effectively solve the problem of high carbon emissions in existing inorganic binder-stabilized materials but also enable the effective utilization of gypsum and further improve the water resistance and mechanical strength of existing inorganic binder-stabilized materials. Summary of the Invention

[0005] In view of this, the present invention provides an application of high free calcium belite sulfoaluminate clinker in the preparation of high-strength binder stabilized crushed stone material. Through the rational design of the mineral composition and content of high free calcium belite sulfoaluminate clinker (hereinafter referred to as clinker), a high-strength binder stabilized crushed stone material was successfully prepared. This high-strength binder stabilized crushed stone material not only has excellent compressive strength and water resistance, but also has low carbon emissions.

[0006] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: In a first aspect, the present invention provides the application of high-free-calcium, high-belite calcium sulfoaluminate clinker in the preparation of high-strength binder stabilized crushed stone materials. The high-free-calcium, high-belite calcium sulfoaluminate clinker comprises the following mineral components by mass percentage: anhydrous calcium sulfoaluminate 25.31%~33.27%, free calcium sulfate 6.55%~12.26%, free calcium oxide 14.82%~19.71%, belite 27.27%~33.87%, and iron phase 3.04%~6.08%.

[0007] Compared to existing technologies, the application of high-free-calcium, high-belite calcium sulfoaluminate clinker provided by this invention in the preparation of high-strength binder stabilized crushed stone materials involves introducing an appropriate amount of free calcium sulfate into the clinker minerals. This free calcium sulfate can form a liquid phase at high temperatures, and anhydrous calcium sulfoaluminate can dissolve in this liquid phase, generating a mixture of amorphous anhydrous calcium sulfoaluminate and cubic anhydrous calcium sulfoaluminate. In the presence of free calcium sulfate, the activity of cubic anhydrous calcium sulfoaluminate is significantly higher than that of orthorhombic anhydrous calcium sulfoaluminate in conventional sulfoaluminate clinker. Simultaneously, a significant amount of free calcium oxide is introduced into the clinker. Free calcium oxide possesses high hydration activity and reacts rapidly upon contact with water. Sufficient free calcium can react with amorphous anhydrous calcium sulfoaluminate, cubic anhydrous calcium sulfoaluminate, and free calcium sulfate to generate a large number of highly active monosulfide-type hydrated calcium sulfoaluminate (AFm) microcrystals. These AFm microcrystals directly react with the added gypsum to generate ettringite (AFt) microcrystals. After their formation, these AFt microcrystals gradually encapsulate the dihydrate gypsum crystals generated by the hydration of the added gypsum. Specific amounts of free calcium and free calcium sulfate significantly enhance the activity of other minerals in the clinker and the clinker as a whole. The aforementioned reactants exhibit high activity, and the AFm microcrystals are small in size with excellent encapsulation effects. This allows the high-strength binder to rapidly form a skeleton in the stable crushed stone material, generating a dense microstructure and producing high early strength.

[0008] Preferably, the belite comprises dicalcium silicate (C2S).

[0009] Preferably, the iron phase comprises tetracalcium aluminoferrite (C4AF).

[0010] Preferably, the high free calcium belite sulfoaluminate clinker further includes 5.03% to 7.66% mixed mineral components.

[0011] For example, based on a mass content of 100% high free calcium belite sulfoaluminate clinker, the mixed mineral composition includes 2%~4% periclase (MgO), 0.85%~2.55% perovskite (CaTiO3), and 0.5%~1.5% alkali metal sulfates.

[0012] Preferably, the high free calcium berit sulfoaluminate clinker comprises the following oxides in mass percentage: SiO2 9.5%~11.8%, Al2O3 14%~18%, CaO 55%~58%, SO3 8%~11%, and Fe2O3 1%~2%.

[0013] More preferably, the high-free-calcium belite sulfoaluminate clinker further includes 4% to 6.7% mixed oxides.

[0014] For example, the hybrid oxides include at least one of MgO, TiO2, Na2O or K2O.

[0015] Preferably, the specific surface area of ​​the high free calcium belite sulfoaluminate clinker is ≥500 m². 2 / kg.

[0016] More preferably, the specific surface area of ​​the high free calcium belite sulfoaluminate clinker is 510 m². 2 / kg ~550m 2 / kg.

[0017] Preferably, the preparation method of the high free calcium belite sulfoaluminate clinker includes the following steps: Limestone, bauxite and gypsum are mixed and ground to obtain raw material; The raw material is calcined at 1200℃~1300℃ to obtain the high free calcium berite sulfoaluminate clinker.

[0018] More preferably, the chemical components in the raw material satisfy the following: ([CaO]-1.87×[SiO2]-1.05×[Fe2O3]-0.7×[TiO2]-0.55×[Al2O3]-0.7×[SO3]) / (100%-loss on ignition of raw meal)= 14.82%~19.71%; (1.7×[SO3]-0.45×[Al2O3]+0.28×[Fe2O3]) / (100%-loss on ignition of raw meal)=6.55%~12.26%.

[0019] It should be noted that in this invention, [CaO] represents the mass percentage of CaO in the raw material, [SiO2] represents the mass percentage of SiO2 in the raw material, [Fe2O3] represents the mass percentage of Fe2O3 in the raw material, [TiO2] represents the mass percentage of TiO2 in the raw material, [Al2O3] represents the mass percentage of Al2O3 in the raw material, and [SO3] represents the mass percentage of SO3 in the raw material.

[0020] More preferably, the mass ratio of limestone, bauxite and gypsum is (60~71): (17~23): (12~19).

[0021] More preferably, the particle size of the raw material is less than 15% after passing through a 0.08mm square hole sieve.

[0022] For example, calcination is carried out in a rotary kiln, and the time from entering the kiln to exiting the kiln is 30 to 60 minutes. The specific calcination time can be adjusted according to the specific conditions of different rotary kilns.

[0023] For example, after calcination, the process also includes cooling and grinding to obtain powdered high-free-calcium belite sulfoaluminate clinker.

[0024] Secondly, the present invention provides a high-strength binder-stabilized crushed stone material, comprising the following raw materials: a low-carbon, waste-utilizing high-strength binder, aggregates, and water; wherein... The low-carbon, waste-utilizing, high-strength binder comprises the following raw materials in the following mass percentages: 5%~36% of the high-free-calcium belite sulfoaluminate clinker, 12%~40% of gypsum, and 45%~79% of granulated blast furnace slag powder; The aggregate includes at least one of graded crushed stone or graded gravel.

[0025] The high-strength binder stabilized crushed stone material provided by this invention integrates low-carbon, waste-utilizing high-strength binder with aggregates. Under the action of highly active components, the low-carbon, waste-utilizing high-strength binder undergoes a hydration reaction, rapidly forming a large number of AFt microcrystals and C-(A)-SH gel, which fully coat the dihydrate gypsum generated during hydration. At the same time, the clinker contains a high amount of free calcium oxide and calcium sulfate. The free calcium oxide also reacts with the ultrafine silica-alumina components in the aggregates to generate AFt microcrystals and C-(A)-SH gel, which bind the aggregate particles together, further improving the density and mechanical properties of the material, thereby forming a high-strength binder stabilized crushed stone material.

[0026] In this invention, the low-carbon, waste-utilizing, high-strength binder uses gypsum and granulated blast furnace slag powder as the main raw materials, and incorporates specially designed clinker. This allows the dihydrate gypsum crystals formed by the external gypsum to be double-densified by AFt microcrystals and C-(A)-SH gel. Even with a high gypsum content, this prevents the easily water-soluble dihydrate gypsum from dissolving in water. As the microstructure gradually becomes denser, the porosity of the high-strength binder-stabilized crushed stone material gradually decreases. This solves the problems of poor water resistance, significant strength reduction, and poor freeze-thaw resistance of gypsum materials caused by the high solubility of dihydrate gypsum, effectively improving the unconfined compressive strength and durability of the high-strength binder-stabilized crushed stone material.

[0027] Preferably, the gypsum includes at least one of the following: dried desulfurized gypsum, dried phosphogypsum, wet desulfurized gypsum, wet phosphogypsum, fluorogypsum, building gypsum, α-type high-strength gypsum, anhydrite, or dihydrate gypsum.

[0028] In the field of gypsum treatment, the difficulty of processing different types of gypsum varies significantly, with the treatment of phosphogypsum being a long-standing technical challenge in China. Consequently, most gypsum treatment technologies currently on the market are limited to single types of gypsum, resulting in a narrow range of applications. This invention achieves a key breakthrough, being adaptable to almost all types of gypsum, especially exhibiting excellent compatibility with industrial by-product gypsum. It eliminates the need for special screening or limitation of gypsum types, providing highly efficient and energy-saving processing throughout the entire process, demonstrating strong versatility.

[0029] It is noteworthy that the fluorogypsum, phosphogypsum, and desulfurization gypsum involved in this invention all belong to industrial solid wastes that are currently stockpiled in large quantities and are still being generated. Resource utilization of these wastes can not only effectively solve the problem of solid waste disposal and alleviate environmental pressure, but also significantly reduce the production cost of the high-strength binder stabilized crushed stone material prepared by this invention, achieving a dual improvement in environmental and economic benefits.

[0030] Preferably, the gypsum contains ≥35% sulfur trioxide.

[0031] In this invention, building gypsum is a material mainly composed of hemihydrate gypsum, produced by heating natural gypsum or industrial by-product gypsum (such as desulfurized gypsum and phosphogypsum) to 150℃~170℃ to remove some of the water of crystallization. Desulfurized gypsum, phosphogypsum, and fluorogypsum meet the requirements of GB / T 21371-2019 "Industrial By-product Gypsum for Cement," and phosphogypsum also meets the requirements of GB / T23456-2018 "Phosphogypsum"; building gypsum meets the requirements of GB / T 9776-2022 "Building Gypsum"; α-type high-strength gypsum meets the requirements of JC / T 2038-2010 "α-type High-strength Gypsum"; and anhydrite and dihydrate gypsum meet the requirements of GB / T 5483-2024 "Natural Gypsum."

[0032] In this invention, the granulated blast furnace slag powder meets the requirements of GB / T 18046-2017 "Granulated blast furnace slag powder for use in cement, mortar and concrete" for granulated blast furnace slag powder of grade not lower than S75, preferably S95 grade.

[0033] Preferably, the low-carbon, waste-utilizing, high-strength binder further includes the following raw materials in weight percentage: 0-25% fly ash, 0-0.55% water-reducing agent, and 0-0.9% retarder.

[0034] More preferably, the water-reducing agent includes at least one of melamine-based high-efficiency water-reducing agents, polycarboxylate water-reducing agents, melamine water-reducing agents, or naphthalene-based water-reducing agents.

[0035] More preferably, the retarder includes at least one of zinc carbonate, tartaric acid, citric acid, sodium citrate, sodium gluconate, or gypsum retarder.

[0036] Preferably, the preparation method of the low-carbon waste-utilizing high-strength binder includes the following steps: weigh each raw material according to the designed ratio, mix them evenly, and obtain the low-carbon waste-utilizing high-strength binder.

[0037] In this invention, the aggregate can be a mixture of crushed stone and gravel, that is, the oversized particles in the gravel are crushed and then mixed with the gravel to form graded crushed gravel.

[0038] For example, graded crushed stone includes 20mm-30mm coarse crushed stone, 10mm-20mm medium crushed stone, 5mm-10mm fine crushed stone and stone chips in a mass ratio of (20-40): (20-30): (20-30): (30-40), and graded gravel includes 20mm-40mm coarse gravel, 10mm-20mm medium gravel, 5mm-10mm fine gravel and sand in a mass ratio of (30-50): (20-30): (20-30): (30-40).

[0039] Preferably, the mass ratio of the low-carbon, waste-utilizing, high-strength binder to the aggregate is (0.03~0.20):1.

[0040] More preferably, the mass ratio of the low-carbon, waste-utilizing, high-strength binder to the aggregate is (0.05~0.20):1.

[0041] The present invention does not have a special limitation on the amount of water used, which can be determined according to the relevant methods in JTG 3441-2024 "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering", that is, the optimal moisture content is first determined, and then the relevant strength test is carried out with the optimal moisture content.

[0042] Preferably, the high-strength binder stabilized crushed stone material has a 7-day unconfined compressive strength ≥3.6MPa and a 28-day unconfined compressive strength ≥9.2MPa.

[0043] Through extensive testing, this invention has revealed that the high-strength binder stabilized crushed stone material provided by this invention has a maximum 7-day unconfined compressive strength of 25.6 MPa and a maximum 28-day unconfined compressive strength of 36.1 MPa, which is far superior to existing technologies.

[0044] Thirdly, the present invention provides a method for preparing the high-strength binder stabilized crushed stone material, comprising the following steps: Low-carbon, waste-utilizing, high-strength binder, aggregates, and water are mixed, and then mixed, compacted, and cured to obtain high-strength binder stabilized crushed stone material.

[0045] This invention mixes low-carbon, waste-utilizing, high-strength binder with aggregates in a certain proportion, and shapes and cures them according to JTG 3441-2024 "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering". After testing, the high-strength binder stabilized crushed stone material made from low-carbon, waste-utilizing, high-strength binder has a greater strength when cured in standard water than when cured in standard dry air.

[0046] The present invention has the following beneficial effects: In the low-carbon, waste-utilizing, high-strength binder of this invention, clinker and granulated blast furnace slag powder have a synergistic effect, which can improve the types, composition, and microstructure of gypsum hydration products, and directionally grow water-resistant hydration products around dihydrate gypsum, avoiding external moisture from dissolving dihydrate gypsum, thereby significantly improving the water resistance and mechanical strength of the high-strength binder stabilized crushed stone material.

[0047] In this invention, gypsum and granulated blast furnace slag powder are inexpensive, significantly reducing production costs and providing a new technical approach for the development of high-strength binder stabilized crushed stone materials. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0049] In this invention, the granulated blast furnace slag powder is grade S95 and was purchased from Qian'an Shengjiu Building Materials Co., Ltd.; desulfurized gypsum and desulfurized gypsum-based building gypsum were purchased from Luanxian Fuyou Renewable Resources Co., Ltd.; α-type high-strength gypsum was purchased from Pingyi Yuantong Gypsum Products Co., Ltd.; anhydrite was purchased from Anhui Huantai New Materials Co., Ltd.; wet phosphogypsum and phosphogypsum-based building gypsum were purchased from Tangshan Polar Bear Building Materials Co., Ltd.; polycarboxylate superplasticizer was purchased from Suzhou Fuke Technology Co., Ltd.; AG-46 gypsum retarder was selected and purchased from Hubei Zhaojia Materials Co., Ltd.; sodium gluconate was purchased from Xiwang Group Co., Ltd. Other products not specified by manufacturer are all conventional products that can be obtained commercially.

[0050] The aggregate used in the embodiments and comparative examples of this invention is graded crushed stone, including 20mm~30mm crushed stone, 10mm~20mm crushed stone, 5mm~10mm crushed stone and stone chips in a mass ratio of 20:22:22:36.

[0051] To better illustrate the present invention, further examples are provided below.

[0052] Examples 1-14 Examples 1-14 provide a high-strength binder stabilized crushed stone material, composed of low-carbon, waste-utilized high-strength binder, aggregate, and water, with specific proportions shown in Table 1. The high-free-calcium belite sulfoaluminate clinker comprises the following mineral components by mass percentage: anhydrous calcium sulfoaluminate 32.08%, free calcium sulfate 9.57%, free calcium oxide 16.92%, belite 29.27%, iron phase 6.08%, and mixed mineral components 6.08%. Further, the high-free-calcium, high-belite calcium sulfoaluminate clinker comprises the following oxides by mass percentage: SiO2 10.20%, Al2O3 17.40%, CaO 55.20%, SO3 9.80%, Fe2O3 2.00%, and mixed oxides 5.40%.

[0053] The preparation method of the above-mentioned high-strength binder stabilized crushed stone material includes the following steps: S100. According to the chemical composition ratio, weigh the raw materials limestone, bauxite and gypsum. The mass ratio of limestone, bauxite and gypsum is 61.9 : 20.6 : 17.5. After mixing and grinding, the residue after passing through a 0.08mm square hole sieve is 13.4%, and the raw material is obtained.

[0054] The chemical components in the raw material satisfy the following: ([CaO]-1.87×[SiO2]-1.05×[Fe2O3]-0.7×[TiO2]-0.55×[Al2O3]-0.7×[SO3]) / (100%-loss on ignition of raw meal)=16.92%; (1.7×[SO3]-0.45×[Al2O3]+0.28×[Fe2O3]) / (100%-loss on ignition of raw meal)=9.57%.

[0055] S200: The raw material is calcined in a rotary kiln at 1250℃ and then ground to obtain a specific surface area of ​​533 m². 2 / kg of high free calcium belite sulfoaluminate clinker.

[0056] S300. Weigh each raw material (clinker, building gypsum, granulated blast furnace slag powder, water-reducing agent, and retarder) according to the design ratio, mix them evenly, and obtain a low-carbon, waste-utilizing, high-strength binder. Specifically, the water-reducing agent in Examples 1-6 and Examples 10-14 is a polycarboxylate water-reducing agent; the water-reducing agents in Examples 7, 8, and 9 are a melamine-based high-efficiency water-reducing agent, a melamine-based water-reducing agent, and a naphthalene-based water-reducing agent, respectively. The retarder in Examples 1-5 is a gypsum retarder; the retarder in Examples 10-14 is sodium gluconate; and the retarder in Examples 6, 7, 8, and 9 is zinc carbonate, tartaric acid, citric acid, and sodium citrate, respectively.

[0057] Examples 1-14 do not specify the order of S100-S200 and S300.

[0058] S400: Mix low-carbon, waste-utilizing, high-strength binder, aggregates, and water, and then mix, compact, and cure (in accordance with JTG 3441-2024 "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering") to obtain high-strength binder stabilized crushed stone material.

[0059] Unconfined compressive strength tests were conducted on the high-strength binder stabilized crushed stone materials obtained in Examples 1-14, and the test results are shown in Table 1.

[0060] Table 1. Raw material ratios and properties of high-strength binder stabilized crushed stone materials in Examples 1-14

[0061] As can be seen from the table above, the low-carbon, waste-utilizing, high-strength binder in the embodiments of the present invention contains 5%~35% high-free-calcium belite sulfoaluminate clinker, 12%~40% desulfurized gypsum, and 45%~79% granulated blast furnace slag powder. After mixing with aggregates at a mass ratio of (0.03~0.20):1 and an appropriate amount of water, a high-strength binder-stabilized crushed stone material with excellent performance can be prepared. The 7-day unconfined compressive strength of the obtained high-strength binder-stabilized crushed stone material is 3.6MPa~25.6MPa, and the 28-day unconfined compressive strength is 9.2MPa~36.1MPa.

[0062] Examples 15-22 Examples 15-22 each provide a high-strength binder stabilized crushed stone material, composed of a low-carbon, waste-utilizing high-strength binder, aggregates, and water; the mass ratio of the low-carbon, waste-utilizing high-strength binder to the aggregates is 0.05:1. The raw materials for the low-carbon, waste-utilizing high-strength binder are all 9% high-free-calcium belite sulfoaluminate clinker, 18% gypsum, and 73% granulated blast furnace slag powder, but the type of gypsum is different, as shown in Table 2. The mineral composition and corresponding oxides of the high-free-calcium belite sulfoaluminate clinker are the same as in Examples 1-14, and will not be repeated here.

[0063] The preparation method of the above-mentioned high-strength binder stabilized crushed stone material includes the following steps: S100~S200 are the same as S100~S200 in Examples 1~14, and will not be described again.

[0064] S300. Weigh each raw material (clinker, gypsum and granulated blast furnace slag powder) according to the design ratio, mix them evenly, and obtain a low-carbon, waste-utilizing, high-strength binder.

[0065] Examples 15-22 do not specify the order of S100-S200 and S300.

[0066] S400: Mix low-carbon, waste-utilizing, high-strength binder, aggregates, and water, and then mix, compact, and cure (in accordance with JTG 3441-2024 "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering") to obtain high-strength binder stabilized crushed stone material.

[0067] Unconfined compressive strength tests were conducted on the high-strength binder stabilized crushed stone materials obtained in Examples 15-22, and the test results are shown in Table 2.

[0068] Table 2. Gypsum Selection and Properties of High-Strength Binder Stabilized Crushed Stone Materials in Examples 15-22

[0069] Analysis of the raw material composition (mainly gypsum type) and properties of the high-strength binder stabilized crushed stone materials in Examples 15-22 above shows that the high-strength binder stabilized crushed stone materials provided by the present invention are applicable to various types of gypsum, with an unconfined compressive strength of 3.8MPa~5.6MPa at 7 days and 11.3MPa~14.1MPa at 28 days.

[0070] Examples 23-25 Examples 23-25 ​​each provide a high-strength binder-stabilized crushed stone material, composed of low-carbon, waste-utilizing high-strength binder, aggregates, and water, with specific dosage ratios shown in Table 3. The mineral composition and corresponding oxides of the high-free-calcium belite sulfoaluminate clinker are the same as in Examples 1-14 and will not be repeated here.

[0071] The preparation method of the above-mentioned high-strength binder stabilized crushed stone material includes the following steps: S100~S200 are the same as S100~S200 in Examples 1~14, and will not be described again.

[0072] S300. Weigh each raw material (clinker, anhydrite, granulated blast furnace slag powder and fly ash) according to the design ratio, mix them evenly, and obtain a low-carbon, waste-utilizing, high-strength binder.

[0073] Examples 23-25 ​​do not specify the order of S100-S200 and S300.

[0074] S400: Mix low-carbon, waste-utilizing, high-strength binder, aggregates, and water, and then mix, compact, and cure (in accordance with JTG 3441-2024 "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering") to obtain high-strength binder stabilized crushed stone material.

[0075] Unconfined compressive strength tests were conducted on the high-strength binder stabilized crushed stone materials obtained in Examples 23-25, and the test results are shown in Table 3.

[0076] Table 3. Raw material ratios and properties of high-strength binder stabilized crushed stone materials in Examples 23-25

[0077] As can be seen from the table above, as the amount of fly ash added to the low-carbon waste-utilizing high-strength binder increases from 5% to 25%, the 7-day and 28-day unconfined compressive strengths of the high-strength binder stabilized crushed stone material decrease slightly. The 7-day unconfined compressive strength is 3.8MPa~4.8MPa, and the 28-day unconfined compressive strength is 12.6MPa~13.9MPa.

[0078] Example 26 This embodiment provides a high-strength binder stabilized crushed stone material, composed of low-carbon waste-utilizing high-strength binder, aggregate, and water; the mass ratio of low-carbon waste-utilizing high-strength binder to aggregate is 0.05:1. The raw materials for the low-carbon waste-utilizing high-strength binder are 9% high-free calcium belite sulfoaluminate clinker, 18% anhydrite, and 73% granulated blast furnace slag powder.

[0079] The high-free-calcium belite sulfoaluminate clinker comprises the following mineral components by mass percentage: anhydrous calcium sulfoaluminate 32.87%, free calcium sulfate 11.09%, free calcium oxide 17.12%, belite 27.84%, iron phase 6.08%, and mixed mineral components 5.00%. Further, the high-free-calcium, high-belite calcium sulfoaluminate clinker comprises the following oxides by mass percentage: SiO2 9.70%, Al2O3 17.80%, CaO 55.60%, SO3 10.80%, Fe2O3 2.00%, and mixed oxides 4.82%.

[0080] The preparation method of the above-mentioned high-strength binder stabilized crushed stone material includes the following steps: S100. According to the chemical composition ratio, weigh the raw materials limestone, bauxite and gypsum. The mass ratio of limestone, bauxite and gypsum is 62.5:19.5:18. After mixing and grinding, the residue after passing through a 0.08mm square hole sieve is 13.2%, and the raw material is obtained.

[0081] The chemical components in the raw material satisfy the following: ([CaO]-1.87×[SiO2]-1.05×[Fe2O3]-0.7×[TiO2]-0.55×[Al2O3]-0.7×[SO3]) / (100%-loss on ignition of raw meal)= 17.12%; (1.7×[SO3]-0.45×[Al2O3]+0.28×[Fe2O3]) / (100%-loss on ignition of raw meal)=11.09%.

[0082] S200: The raw material is calcined in a rotary kiln at 1250℃ and then ground to obtain a specific surface area of ​​535m². 2 / kg of high free calcium belite sulfoaluminate clinker.

[0083] S300. Weigh each raw material (clinker, anhydrite and granulated blast furnace slag powder) according to the design ratio, mix them evenly, and obtain a low-carbon, waste-utilizing, high-strength binder.

[0084] This embodiment does not limit the order of S100~S200 and S300.

[0085] S400: Mix low-carbon, waste-utilizing, high-strength binder, aggregates, and water, and then mix, compact, and cure (in accordance with JTG 3441-2024 "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering") to obtain high-strength binder stabilized crushed stone material.

[0086] The high-strength binder stabilized crushed stone material obtained in this embodiment was subjected to unconfined compressive strength test, and the test results are shown in Table 4.

[0087] Example 27 This embodiment provides a high-strength binder stabilized crushed stone material, composed of low-carbon waste-utilizing high-strength binder, aggregate, and water; the mass ratio of low-carbon waste-utilizing high-strength binder to aggregate is 0.05:1. The raw materials for the low-carbon waste-utilizing high-strength binder are 9% high-free calcium belite sulfoaluminate clinker, 18% anhydrite, and 73% granulated blast furnace slag powder.

[0088] The high-free-calcium belite sulfoaluminate clinker comprises the following mineral components by mass percentage: anhydrous calcium sulfoaluminate 31.92%, free calcium sulfate 6.55%, free calcium oxide 19.71%, belite 32.14%, iron phase 4.56%, and mixed mineral components 5.12%. Further, the high-free-calcium, high-belite calcium sulfoaluminate clinker comprises the following oxides by mass percentage: SiO2 11.20%, Al2O3 17.00%, CaO 58.00%, SO3 8.00%, Fe2O3 1.50%, and mixed oxides 4.30%.

[0089] The preparation method of the above-mentioned high-strength binder stabilized crushed stone material includes the following steps: S100. According to the chemical composition ratio, weigh the raw materials limestone, bauxite and gypsum. The mass ratio of limestone, bauxite and gypsum is 66.4:19.3:14.3. After mixing and grinding, the residue after passing through a 0.08mm square hole sieve is 13.5%, and the raw material is obtained.

[0090] The chemical components in the raw material satisfy the following: ([CaO]-1.87×[SiO2]-1.05×[Fe2O3]-0.7×[TiO2]-0.55×[Al2O3]-0.7×[SO3]) / (100%-loss on ignition of raw meal)= 19.71%; (1.7×[SO3]-0.45×[Al2O3]+0.28×[Fe2O3]) / (100%-loss on ignition of raw meal)=6.55%.

[0091] S200: The raw material is calcined in a rotary kiln at 1250℃ and then ground to obtain a specific surface area of ​​531 m². 2 / kg of high free calcium belite sulfoaluminate clinker.

[0092] S300. Weigh each raw material (clinker, anhydrite and granulated blast furnace slag powder) according to the design ratio, mix them evenly, and obtain a low-carbon, waste-utilizing, high-strength binder.

[0093] This embodiment does not limit the order of S100~S200 and S300.

[0094] S400: Mix low-carbon, waste-utilizing, high-strength binder, aggregates, and water, and then mix, compact, and cure (in accordance with JTG 3441-2024 "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering") to obtain high-strength binder stabilized crushed stone material.

[0095] The high-strength binder stabilized crushed stone material obtained in this embodiment was subjected to unconfined compressive strength test, and the test results are shown in Table 4.

[0096] Table 4 Performance of high-strength binder stabilized crushed stone materials from Examples 26-27

[0097] As can be seen from the table above, the low-carbon, high-strength binders produced from different clinker materials provided in the embodiments of the present invention can all be used to consolidate aggregates. The 7-day unconfined compressive strength of the high-strength binder stabilized crushed stone material is 5.5 MPa to 6.0 MPa, and the 28-day unconfined compressive strength is 12.1 MPa to 11.7 MPa.

[0098] Comparative Example 1 This comparative example provides an inorganic binder stabilized material composed of Jidong silicate cement PO42.5, aggregates, and water; the mass ratio of Jidong silicate cement PO42.5 to aggregates is 0.05:1.

[0099] The preparation method of the above-mentioned inorganic binder stabilized material includes the following steps: Jidong silicate cement PO42.5, aggregates and water are mixed, and then mixed, compacted and cured (in accordance with JTG 3441-2024 "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering") to obtain inorganic binder stabilized material.

[0100] The inorganic binder stabilized material obtained in this comparative example was subjected to unconfined compressive strength test, and the test results are shown in Table 5.

[0101] Comparative Example 2 This comparative example provides an inorganic binder stabilizing material composed of gypsum-based binder, aggregate, and water; the mass ratio of gypsum-based binder to aggregate is 0.05:1. The raw materials for the gypsum-based binder are 9% clinker, 18% anhydrite, and 73% granulated blast furnace slag powder, consistent with the proportions in Examples 15 and 26-27. The difference lies in that the clinker is the clinker provided in Example 6 of patent ZL201711219814.4, which includes the following mineral components by mass percentage: 28% anhydrous calcium sulfoaluminate, 16% free calcium sulfate, 3% free calcium oxide, 45% belite, 6% iron phase, and 2% mixed mineral components.

[0102] The preparation method of the above-mentioned inorganic binder stabilized material includes the following steps: S100. Weigh each raw material (clinker, anhydrite and granulated blast furnace slag powder) according to the design ratio, mix them evenly, and obtain gypsum-based binder.

[0103] S200. Gypsum-based binder, aggregate and water are mixed, and then mixed, compacted and cured (in accordance with JTG 3441-2024 "Test Procedure for Inorganic Binder Stabilized Materials for Highway Engineering") to obtain inorganic binder stabilized material.

[0104] The inorganic binder stabilized material obtained in this comparative example was subjected to unconfined compressive strength test, and the test results are shown in Table 5.

[0105] Table 5. Performance of inorganic binder stabilized crushed stone materials from Comparative Examples 1-2

[0106] As can be seen from the table above, the 7-day and 28-day unconfined compressive strengths of the high-strength binder stabilized crushed stone material provided in the embodiments of the present invention are much higher than the strengths of the inorganic binder stabilized crushed stone material provided in the comparative embodiment under the same conditions.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The application of a high-free-calcium, high-belite calcium sulfoaluminate clinker in the preparation of high-strength binder stabilized crushed stone materials, characterized in that, The high-free-calcium, high-belite calcium sulfoaluminate clinker comprises the following mineral components by mass percentage: anhydrous calcium sulfoaluminate 25.31%~33.27%, free calcium sulfate 6.55%~12.26%, free calcium oxide 14.82%~19.71%, belite 27.27%~33.87%, and iron phase 3.04%~6.08%.

2. The application of the high-free-calcium, high-belite calcium sulfoaluminate clinker as described in claim 1 in the preparation of high-strength binder stabilized crushed stone materials, characterized in that, The high free calcium berite sulfoaluminate clinker comprises the following oxides in mass percentage: SiO2 9.5%~11.8%, Al2O3 14%~18%, CaO 55%~58%, SO3 8%~11% and Fe2O3 1%~2%.

3. A high-strength binder-stabilized crushed stone material, characterized in that, It includes the following raw materials: low-carbon, waste-utilizing, high-strength binder, aggregates, and water; among which, The low-carbon, waste-utilizing, high-strength binder comprises the following raw materials in the following mass percentages: 5%~36% of the high free calcium belite sulfoaluminate clinker as described in claim 1 or 2, 12%~40% of gypsum, and 45%~79% of granulated blast furnace slag powder; The aggregate includes at least one of graded crushed stone or graded gravel.

4. The high-strength binder stabilized crushed stone material as described in claim 3, characterized in that, The gypsum includes at least one of the following: dried desulfurized gypsum, dried phosphogypsum, wet desulfurized gypsum, wet phosphogypsum, fluorogypsum, building gypsum, α-type high-strength gypsum, anhydrite, or dihydrate gypsum.

5. The high-strength binder stabilized crushed stone material as described in claim 3 or 4, characterized in that, The gypsum contains ≥35% sulfur trioxide.

6. The high-strength binder stabilized crushed stone material as described in claim 3, characterized in that, The low-carbon, waste-utilizing, high-strength binder also includes the following raw materials in the following mass percentages: 0-25% fly ash, 0-0.55% water-reducing agent, and 0-0.9% retarder.

7. The high-strength binder stabilized crushed stone material as described in claim 3, characterized in that, The preparation method of the low-carbon, waste-utilizing, high-strength binder includes the following steps: Weigh each raw material according to the design ratio, mix them evenly, and obtain the low-carbon, waste-utilizing, high-strength binder.

8. The high-strength binder stabilized crushed stone material as described in claim 3, characterized in that, The mass ratio of the low-carbon, waste-utilizing, high-strength binder to the aggregate is (0.03~0.20):

1.

9. The high-strength binder stabilized crushed stone material as described in claim 3, characterized in that, The high-strength binder stabilized crushed stone material has a 7-day unconfined compressive strength ≥3.6MPa and a 28-day unconfined compressive strength ≥9.2MPa.

10. A method for preparing a high-strength binder-stabilized crushed stone material as described in any one of claims 3 to 9, characterized in that, Includes the following steps: Low-carbon, waste-utilizing, high-strength binder, aggregates, and water are mixed, and then mixed, compacted, and cured to obtain high-strength binder stabilized crushed stone material.

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