High-strength stable solid waste-based composite cementitious material, preparation method and application thereof

Abstract

The application relates to a high-strength stable solid waste-based composite cementing material in the field of building materials and a preparation method and application thereof, which is composed of the following raw materials in parts by weight: composite solid waste micro powder 70-85 parts; silicate cement clinker 10-20 parts; composite activator 3-8 parts; nanoscale functional regulator 0.5-2 parts; wherein the composite solid waste micro powder is prepared by mixing and grinding the following raw materials in parts by weight: blast furnace slag powder 40-60 parts; fly ash 20-30 parts; chemically modified electrolytic manganese slag powder 10-20 parts; steel slag powder 5-15 parts. The electrolytic manganese slag is chemically modified by adopting sodium metasilicate assisted medium-temperature calcination, not only effectively activating the cementing activity of the electrolytic manganese slag, but also fixing free-state manganese, cadmium and other heavy metal ions in the electrolytic manganese slag in situ in newly-formed zeolite-like silicate mineral lattices through thermochemical reconstruction, thus opening a brand-new technical path for safe and high-value utilization of the typical dangerous waste, the electrolytic manganese slag.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a high-strength, stable solid waste-based composite cementitious material, its preparation method, and its application. Background Technology

[0002] Blast furnace slag, fly ash, steel slag, and other bulk industrial solid wastes have been utilized to some extent in the cement and concrete industries as admixtures or additives. However, electrolytic manganese slag, as a hazardous waste generated from the electrolytic manganese industry, has a complex composition, low activity, and contains a high concentration of soluble manganese ions (Mn). 2+ ) and ammonium ions (NH4) + Therefore, achieving safe, efficient, and large-scale resource utilization of hazardous wastes such as electrolytic manganese slag is a key challenge that urgently needs to be addressed in the construction of "zero-waste cities" and the green development of industry.

[0003] Using industrial solid waste to prepare cementitious materials is an important way to achieve large-scale disposal. Currently, the technological development in this field mainly faces the following bottlenecks:

[0004] I. Existing technologies mostly focus on physical grinding or simple alkali activation to enhance the activity of solid waste. For example, CN110467385B discloses an eco-friendly composite cementitious material utilizing solid waste materials, using electrolytic manganese slag, fly ash, and red mud as the matrix, and optimizing performance by controlling the Ca / Si ratio. However, this type of approach has limited activation of the cementitious activity of electrolytic manganese slag, resulting in slow early strength development of the prepared material. The 3-day compressive strength is generally below 15 MPa, which is difficult to meet the requirements of modern engineering construction for rapid hardening and early strength, thus limiting its application in structural engineering or emergency repair projects.

[0005] Second, due to the complexity of various solid waste components and their significant differences in physicochemical properties, the hydration process and products are difficult to control in a coordinated manner, which can easily lead to poor volume stability of the gelation system in the later stages, large drying shrinkage, and consequently, the risk of cracking. Many solid waste-based materials sacrifice the uniformity and stability of the system in pursuit of high admixture levels, affecting the long-term safety and service life of structures.

[0006] Third, existing technologies for treating electrolytic manganese slag mostly rely on physical encapsulation or precipitation in highly alkaline environments, resulting in incomplete and unstable solidification of heavy metals. During long-term service, especially under conditions such as acidic precipitation or carbonization, there is a risk of secondary leaching of heavy metal ions such as manganese and cadmium from the solidified material. For example, while CN110467385B achieves the utilization of electrolytic manganese slag, its solidification effect on manganese ions still has room for improvement, and environmental safety cannot be fully guaranteed.

[0007] Fourth, most current solutions only involve the mechanical mixing of various solid wastes, failing to fundamentally address the issues of matching and synergistic effects in the reactivity and hydration processes of different solid waste components. For example, directly combining slag, fly ash, and unmodified electrolytic manganese slag often results in mutual inhibition among the components, making it difficult to form an optimized and stable hydration product network. This leads to mediocre overall material performance and fails to achieve a synergistic effect of "1+1>2".

[0008] In summary, there is an urgent need in this field for a cementitious material that can simultaneously and synergistically process multiple industrial solid wastes, and possesses high early strength, excellent volume stability, and reliable heavy metal solidification capabilities, in order to solve the technical challenge of balancing performance, environmental protection, and economic benefits in existing technologies. Summary of the Invention

[0009] To overcome the shortcomings of the prior art, this invention discloses a high-strength, stable solid waste-based composite cementitious material, its preparation method, and its application.

[0010] To achieve the above objectives, this invention employs sodium metasilicate-assisted medium-temperature calcination to chemically modify electrolytic manganese slag, achieving the dual goals of activation and heavy metal lattice solidification; it enhances the synergistic stabilization effect of multiple pollutants by introducing a red mud pretreatment system; it optimizes the hydration process through the temporal synergistic effect of composite activators and nucleation inducers; and it comprehensively improves material performance by constructing a multi-scale reinforcing framework through surface-modified nanomaterials and micron-scale reinforcing phases.

[0011] A high-strength, stable solid waste-based composite cementitious material is composed of the following raw materials in parts by weight:

[0012] 70-85 parts of composite solid waste powder;

[0013] 10-20 parts of silicate cement clinker;

[0014] 3-8 parts of composite activator;

[0015] 0.5–2 parts of nanoscale functional modifier;

[0016] The composite solid waste powder is made from the following raw materials by weight through mixing and grinding:

[0017] 40-60 parts of blast furnace slag powder;

[0018] 20-30 parts fly ash;

[0019] 10-20 parts of chemically modified electrolytic manganese slag powder;

[0020] 5-15 parts of steel slag powder;

[0021] The chemically modified electrolytic manganese slag powder is prepared by calcining undisturbed electrolytic manganese slag with sodium metasilicate at medium temperature.

[0022] Furthermore, the raw materials for the composite solid waste micro powder also include 5 to 15 parts by weight of red mud, which is premixed and aged with the chemically modified electrolytic manganese slag powder at a mass ratio of (0.5 to 1.5):1 before the preparation of the composite solid waste micro powder.

[0023] Furthermore, the chemically modified electrolytic manganese slag powder is prepared by the following method: the original electrolytic manganese slag is uniformly mixed with sodium metasilicate accounting for 5% to 12% of its mass, calcined at 680℃ to 720℃ for 0.8 to 1.2 hours, then subjected to rapid cooling treatment, and finally ground to a specific surface area ≥ 500 m² / kg.

[0024] Furthermore, the composite activator is a mixture of sodium sulfate, calcium hydroxide, and silica fume, wherein the mass ratio of sodium sulfate, calcium hydroxide, and silica fume is (2.5-3.5):(1.2-1.8):1;

[0025] The composite activator includes a crystal nucleation inducing agent, which is composed of calcium nitrate and sodium silicate, and the sum of the masses of calcium nitrate and sodium silicate accounts for 1%-5% of the total mass of the composite activator.

[0026] Furthermore, the nanoscale functional regulator is a mixture of nano-silica and nano-aluminum hydroxide obtained by surface modification with a silane coupling agent;

[0027] The mass ratio of nano-silica to nano-aluminum hydroxide is 1.5:1 to 2.5:1.

[0028] Furthermore, the composite solid waste micro powder contains 0.5% to 2% of its total mass of ultrafine steel fibers, which together with the nanoscale functional regulator form a multi-scale reinforcing skeleton.

[0029] This invention also provides a method for preparing a high-strength, stable solid waste-based composite cementitious material, comprising the following steps:

[0030] Step 1: Prepare the chemically modified electrolytic manganese slag powder and composite solid waste micro powder according to the specified proportions;

[0031] Step 2: The composite solid waste powder, silicate cement clinker, composite activator, and nano-scale functional regulator are weighed and mixed according to the specified weight proportions.

[0032] Step 3: Add the materials from Step 2 into the mixing equipment and mix thoroughly to obtain the high-strength stable solid waste-based composite cementitious material.

[0033] This invention also provides the application of a high-strength, stable solid waste-based composite cementitious material in the preparation of marine engineering concrete or solidification and stabilization materials for heavy metal contaminated soil.

[0034] Furthermore, when the cementitious material is used to prepare marine engineering concrete, the resulting concrete meets the requirement that the chloride ion diffusion coefficient is less than 2.0 × 10⁻⁶ after 56 days. -12 m 2 / s requirement.

[0035] Furthermore, when the cementitious material solidifies soil contaminated with heavy metals, the solidification rate of manganese is not less than 99.5%, and the unconfined compressive strength of the solidified body after 28 days is not less than 5 MPa.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] 1. The use of sodium metasilicate-assisted medium-temperature calcination to chemically modify electrolytic manganese slag not only effectively stimulates the cementitious activity of electrolytic manganese slag, but also fixes the free manganese, cadmium and other heavy metal ions in situ into the newly formed zeolite-like silicate mineral lattice through thermochemical reconstruction. This achieves a solidification rate of over 99.5% for heavy metal manganese, with a leaching concentration far below the national standard, opening up a new technical path for the safe and high-value utilization of electrolytic manganese slag, a typical hazardous waste.

[0038] 2. By introducing red mud pretreatment, the inherent strong alkalinity and rich iron and aluminum oxide components of red mud are utilized to produce a synergistic effect with the modified electrolytic manganese slag system. It can not only efficiently solidify manganese ions, but also simultaneously and deeply stabilize ammonium ions through adsorption, co-precipitation and other effects, thus solving the problem of poor ammonium solidification effect of traditional cementing materials.

[0039] 3. The designed composite activator and nucleation inducer can preferentially form CSH gel nucleation sites in the early stage of hydration, guiding the orderly and rapid growth of hydration products. Compared with the traditional single activator, this design significantly optimizes the hydration process. Combined with the pozzolanic effect and nano-filling effect of the surface-modified nanoscale functional regulator, the material exhibits ultra-high early strength (3-day compressive strength ≥25MPa) and excellent long-term strength (28-day compressive strength ≥60MPa), meeting the requirements of modern construction for rapid hardening, early strength, and structural load-bearing capacity.

[0040] 4. By combining surface-modified nanomaterials with micron-sized ultrafine steel fibers, a multi-scale reinforcing skeleton was successfully constructed in the cementitious material matrix. This structure simultaneously improves strength and toughness by filling gel pores with nanoparticles and bridging microcracks with microfibers, effectively constraining the shrinkage deformation of the matrix.

[0041] 5. The main components of the solid waste include slag, fly ash, steel slag, electrolytic manganese slag, and red mud, with a total admixture content of up to 85% or more. This achieves large-scale collaborative disposal of solid waste. Furthermore, the modification, grinding, and mixing processes used are all mature and low-cost industrial technologies, avoiding energy-intensive processes such as melting and sintering. Detailed Implementation

[0042] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited to the following embodiments. Those skilled in the art can make various modifications, substitutions and improvements without departing from the spirit and essence of the present invention.

[0043] The following is some information about the raw materials used:

[0044] Blast furnace slag powder: S95 grade blast furnace slag powder conforming to GB / T18046-2017, with a specific surface area ≥420m². 2 / kg.

[0045] Fly ash: Class F, Grade II fly ash conforming to GB / T1596-2017.

[0046] Steel slag powder: Grade I steel slag powder conforming to GB / T20491-2017, with a specific surface area ≥400m². 2 / kg.

[0047] Electrolytic manganese slag: taken from a domestic electrolytic manganese plant, the main chemical components are shown in Table 1 below.

[0048] Red mud: Bayer process red mud, the main chemical components are shown in Table 1 below.

[0049] Silicate cement clinker: Ordinary silicate cement clinker sold on the market.

[0050] Sodium metasilicate, sodium sulfate, calcium hydroxide, and silica fume: all are commercially available pure industrial products.

[0051] Nano-silica: average particle size 30nm, specific surface area ≥200m² 2 / g refers to industrial products sold on the market.

[0052] Nano aluminum hydroxide: with an average particle size of 50nm, it is an industrial product sold on the market.

[0053] Silane coupling agent: KH-550.

[0054] Ultrafine steel fibers: 3-6 mm in length and 0.1-0.2 mm in diameter.

[0055] Table 1 Chemical composition of main raw materials

[0056]

[0057] The preparation of chemically modified electrolytic manganese slag powder is as follows:

[0058] In Example 1, 1000g of dried undisturbed electrolytic manganese slag and 80g of sodium metasilicate were mixed in a mixer for 30 minutes until homogeneous. The mixture was placed in a muffle furnace and heated to 700°C at a rate of 10°C / min, and calcined at this temperature for 1 hour. After calcination, the material was quickly removed and air-cooled to room temperature (cooling rate approximately 50°C / min). The calcined lumpy material was then ground in a ball mill to a specific surface area of ​​approximately 520 m² / kg to obtain chemically modified electrolytic manganese slag powder A1, which was then sealed and stored for later use.

[0059] In Example 2, 1000g of dried undisturbed electrolytic manganese slag and 100g of sodium metasilicate were mixed in a mixer for 30 minutes until homogeneous. The mixture was placed in a muffle furnace and heated to 720°C at a rate of 10°C / min, and calcined at this temperature for 0.8 hours. After calcination, the material was quickly removed and air-cooled to room temperature. Finally, the calcined lumpy material was ground in a ball mill to a specific surface area of ​​approximately 520 m². 2 / kg, to obtain chemically modified electrolytic manganese slag powder A2, which is sealed and stored for later use.

[0060] In Example 3, 1000g of dried undisturbed electrolytic manganese slag and 60g of sodium metasilicate were mixed in a mixer for 30 minutes until homogeneous. The mixture was placed in a muffle furnace and heated to 680℃ at a rate of 10℃ / min, and calcined at this temperature for 1.2 hours. After calcination, the material was quickly removed and air-cooled to room temperature. Finally, the calcined lumpy material was ground in a ball mill to a specific surface area of ​​approximately 520 m². 2 / kg, to obtain chemically modified electrolytic manganese slag powder A3, which is sealed and stored for later use.

[0061] Red mud pretreatment is as follows:

[0062] Chemically modified electrolytic manganese slag powder A1 was mixed with red mud at a mass ratio of 1:1, and an appropriate amount of water was added to form a slurry (water-to-solid ratio 0.4). The mixture was aged at room temperature for 48 hours, then dried at 105℃ and crushed to obtain pretreated red mud-electrolytic manganese slag composite powder B1.

[0063] The preparation of nanoscale functional modifiers is as follows:

[0064] Nano-silica and nano-aluminum hydroxide were mixed at a mass ratio of 2:1, and KH-550 silane coupling agent (diluted to 5% concentration with ethanol) accounting for 1.5% of the total mass of the nanoparticles was added. The mixture was then treated in a high-speed shear emulsifier at a speed of 3000 r / min for 30 minutes, and then dried at 80℃ to obtain the surface-modified nano-scale functional regulator C1.

[0065] The preparation method of high-strength, stable solid waste-based composite cementitious material is as follows:

[0066] Example 1: Prepare raw materials according to the following ratio:

[0067] 80 parts of composite solid waste micro powder, 15 parts of silicate cement clinker, 4.5 parts of composite activator and 1.5 parts of nano-level functional regulator C1;

[0068] The composite solid waste powder is prepared according to the following proportions:

[0069] 50 parts blast furnace slag powder, 25 parts fly ash, 15 parts chemically modified electrolytic manganese slag powder A1, and 10 parts steel slag powder;

[0070] The composite activator is prepared according to the following proportions:

[0071] 2.25 parts sodium sulfate, 1.13 parts calcium hydroxide, 0.75 parts silica fume, and 0.15 parts crystal nucleation inducing agent; wherein the crystal nucleation inducing agent is composed of calcium nitrate and sodium silicate mixed in a mass ratio of 1:1.5.

[0072] First, blast furnace slag powder, fly ash, chemically modified electrolytic manganese slag powder A1, and steel slag powder are premixed and then ground together in a ball mill for 2 minutes to obtain composite solid waste micro powder.

[0073] Then, the composite solid waste powder, silicate cement clinker, composite activator, and nano-level functional regulator C1 are added into the V-type mixer;

[0074] Finally, mix for 45 minutes until homogeneous to obtain composite cementitious material S1.

[0075] Example 2, based on Example 1, uses pretreated red mud-electrolytic manganese slag composite powder B1 to replace chemically modified electrolytic manganese slag powder A1, wherein the composition of the composite solid waste micro powder is adjusted as follows:

[0076] 45 parts blast furnace slag powder, 25 parts fly ash, 20 parts red mud-electrolytic manganese slag composite powder B1, and 10 parts steel slag powder:

[0077] Among them, 20 parts of red mud-electrolytic manganese slag composite powder B1 were prepared by pretreatment of 10 parts of electrolytic manganese slag powder and 10 parts of red mud.

[0078] Under the same conditions as in Example 1, composite cementitious material S2 was obtained.

[0079] Example 3: Based on Example 1, 1% of the total mass of the composite solid waste powder was added to the composite cementitious material S3, i.e., 0.8 parts of ultrafine steel fiber. Other conditions remained unchanged.

[0080] Comparative Example 1: The composite solid waste micro powder was made from unmodified electrolytic manganese slag powder with the same proportions as in Example 1, but without the addition of nanoscale functional regulators, and the amount of composite activator was increased to 6 parts, resulting in comparative material D1.

[0081] Comparative Example 2: The ratio of composite solid waste micro powder was the same as in Example 1, but only 1.5 parts of unmodified nano silica were used in the nano-level functional regulator, and no nano aluminum hydroxide was added, resulting in comparative material D2.

[0082] Comparative Example 3: The composite solid waste powder ratio was the same as in Example 1, but calcium nitrate and sodium silicate were not added to the composite activator, resulting in comparative material D3.

[0083] The materials prepared above were molded and cured according to GB / T17671-2021 "Test Method for Strength of Cement Mortar". The test results are shown in Table 2 below.

[0084] Table 2: Comparison of Performance Test Results

[0085]

[0086] From the data in Table 2 above, we can see that:

[0087] The 3-day compressive strength of S1 in Example 1 reached 28.5 MPa, and the 28-day compressive strength reached 65.2 MPa. Its strength development rate and final strength were significantly better than the comparative example. Compared with D1 in Comparative Example 1, which used unmodified electrolytic manganese slag and lacked nanoscale functional regulators, this demonstrates the decisive role of chemically modified electrolytic manganese slag powder and nanoscale functional regulators in improving the mechanical properties of the cementitious system. The 56-day drying shrinkage rate of Example S1 was only 0.025%, far lower than the 0.055% of D1 in Comparative Example 1. This indicates that the structure of the hydration products formed by chemical modification is more compact, and the micropore filling by the nanoscale functional regulators and the improved hydration degree of the system jointly reduced the macroscopic shrinkage caused by water evaporation and chemical shrinkage. The manganese leaching concentration of S1 in Example 1 was 0.08 mg / L, far lower than the 3.45 mg / L of D1 in Comparative Example 1, and the solidification rate was as high as 97.7%, indicating that in-situ chemical solidification of manganese ions into the stable mineral lattice was achieved through sodium metasilicate-assisted medium-temperature calcination.

[0088] Example 2, S2, employed red mud pretreatment, and its 28-day compressive strength was comparable to that of Example 1, S1, indicating that the pretreatment method, when introducing red mud, did not negatively impact mechanical properties, providing a foundation for subsequent synergistic solidification. The manganese leaching concentration in Example 2, S2, was further reduced to 0.05 mg / L. Simultaneously, its solidification effect on ammonium ions was particularly outstanding, with the leaching concentration significantly decreasing from 25.6 mg / L in Comparative Example D1 to 0.8 mg / L. This demonstrates that the alkaline environment of the red mud and its contained iron and aluminum oxides and other active components produced a synergistic effect with the modified electrolytic manganese slag system, achieving simultaneous and efficient solidification of multiple pollutants such as manganese and ammonium through adsorption, co-precipitation, and other pathways.

[0089] Example 3, S3, by introducing ultrafine steel fibers and forming a multi-scale reinforcement system with nanoscale functional modifiers, further improved its 28-day compressive strength to 68.9 MPa, and its 3-day early strength reached the highest in the series at 30.2 MPa, demonstrating the further enhancement effect of introducing ultrafine steel fibers on the macroscopic mechanical properties of the material. The drying shrinkage rate of Example 3, S3, was further reduced to 0.022%, proving that the addition of ultrafine steel fibers not only transfers loads but also effectively constrains the shrinkage deformation of the matrix, physically improving the dimensional stability of the material.

[0090] Application Example 1: C40 marine concrete was prepared using cementitious material S1 prepared in Example 1. The 56-day chloride ion diffusion coefficient of this concrete was tested to be 1.8 × 10⁻⁶. -12 m 2 / s, meeting the requirements for durable concrete in the "Technical Specification for Corrosion Protection of Concrete Structures in Harbor Engineering" (JTJ275-2000).

[0091] Application Example 2: Soil from a manganese-contaminated site (manganese leaching concentration 15.6 mg / L, ammonium concentration 32.5 mg / L) was taken. The cementitious material S2 prepared in Example 2 was added at a ratio of 10% of the soil dry weight, and an appropriate amount of water was added and mixed thoroughly. The mixture was then cured for 28 days. Test results showed that the manganese leaching concentration of the solidified body decreased to 0.05 mg / L, and the ammonium concentration decreased to 1.2 mg / L. The solidification rates reached 99.7% and 96.3%, respectively, and its 28-day unconfined compressive strength reached 6.2 MPa.

[0092] The parts of this invention not described in detail are prior art. It will be apparent to those skilled in the art that this invention is not limited to the details of the above exemplary embodiments, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the above embodiments should be regarded as exemplary and non-limiting in all respects. The scope of this invention is defined by the appended claims rather than the foregoing description, and therefore all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within this invention.

Claims

1. A high-strength stable solid waste-based composite cementitious material, characterized in that, It is composed of the following raw materials by weight: Composite solid waste micro powder 70-85 parts; Silicate cement clinker 10-20 parts; Composite activator 3-8 parts; Nanoscale functional regulator 0.5-2 parts; The composite solid waste micro powder is made by mixing and grinding the following raw materials by weight: Blast furnace slag powder 40-60 parts; Fly ash 20-30 parts; Chemically modified electrolytic manganese slag powder 10-20 parts; Steel slag powder 5-15 parts; Red mud 5-15 parts; The red mud is pre-mixed with the chemically modified electrolytic manganese slag powder in a mass ratio of (0.5-1.5):1 before preparing the composite solid waste micro powder and is subjected to aging treatment; The chemically modified electrolytic manganese slag powder is prepared by uniformly mixing raw electrolytic manganese slag with 5%-12% sodium metasilicate based on the mass of the raw electrolytic manganese slag, calcining at 680°C-720°C for 0.8-1.2 hours, then subjecting to quenching treatment, and finally grinding to a specific surface area of ≥500 m² / kg; the composite activator is sodium sulfate, calcium hydroxide, silica fume, and a crystal nucleus inducer, wherein the mass ratio of sodium sulfate, calcium hydroxide, and silica fume is (2.5-3.5):(1.2-1.8):1; The crystal nucleus inducer is composed of calcium nitrate and sodium silicate, and the sum of the mass of calcium nitrate and sodium silicate accounts for 1%-5% of the total mass of the composite activator; The mass ratio of calcium nitrate to sodium silicate is 1:(1-3); The nanoscale functional regulator is a mixture obtained by surface modification of nanosilica and nano-aluminum hydroxide with a silane coupling agent; The mass ratio of nanosilica to nano-aluminum hydroxide is 1.5:1-2.5:

1.

2. The high-strength stable solid-waste-based composite cementitious material according to claim 1, characterized in that: The composite solid waste micro powder contains 0.5%-2% ultra-fine steel fibers based on the total mass of the composite solid waste micro powder, and together with the nanoscale functional regulator, forms a multi-scale reinforced framework.

3. A method of making the high-strength, stabilized solid-waste-based composite cementitious material of claim 1 or 2, characterized by: It comprises the following steps: Step one: prepare the chemically modified electrolytic manganese slag powder and the composite solid waste micro powder according to the proportions; Step two: measure and proportion the composite solid waste micro powder, silicate cement clinker, composite activator, and nanoscale functional regulator according to the weight parts; Step three: put the materials in step two into a mixing device, mix thoroughly, and obtain the high-strength and stable solid waste-based composite cementitious material.

4. The use of the high-strength and stable solid waste-based composite cementitious material according to claim 1 or 2 in the preparation of marine engineering concrete or heavy metal contaminated soil solidification and stabilization material.

5. The use of the high-strength stable solid waste-based composite cementitious material according to claim 4 in the preparation of marine engineering concrete or heavy metal contaminated soil solidification and stabilization material, characterized in that, The cementitious material, when used in preparing marine engineering concrete, the prepared concrete satisfies the requirement that the chloride ion diffusion coefficient is less than 2.0 x 10 -12 m 2 / s at 56 days.

6. The use of the high-strength stable solid waste-based composite cementitious material according to claim 4 in the preparation of marine engineering concrete or heavy metal contaminated soil solidification and stabilization material, characterized in that, When the cementitious material is used to solidify heavy metal contaminated soil, the solidification rate of heavy metal manganese is not less than 99.5%, and the unconfined compressive strength of the solidified body after 28 days is not less than 5 MPa.

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