Superfine cementitious material, and preparation method and application thereof

Abstract

The application discloses a superfine cementing material and a preparation method and application thereof, and belongs to the technical field of solid waste recycling. The raw materials of the superfine cementing material include 45-55 parts of slag powder, 13-25 parts of steel slag powder, 26-37 parts of fly ash and 0.05-0.2 parts of a solubilization activator in terms of weight percentage; wherein the solubilization activator contains at least one of plant acid, alcohol polymer compound, sugar-based biological surfactant and silicate compound. The superfine cementing material contains aluminum-oxygen-silicate tetrahedral three-dimensional network polymer, has good and durable cementing activity, and has low porosity, low total pore surface area, high compactness and high compressive strength, and can be used in building materials or roadbed materials. The preparation method is simple and easy to operate.

Description

Technical Field

[0001] This invention relates to the field of solid waste recycling technology, and more specifically, to an ultrafine cementitious material, its preparation method, and its application. Background Technology

[0002] Steel slag powder is the main waste generated during the steelmaking process, but it is mostly left in a state of abandonment and accumulation. Although researchers have carried out a series of studies and applications on the comprehensive utilization of steel slag powder in recent years, they have encountered certain difficulties in the large-scale utilization of steel slag powder in building materials. For example, when steel slag powder is used as a concrete admixture or aggregate in building materials in recent years, some of it will expand and crack after a few years.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide an ultrafine cementitious material, its preparation method, and its application, so as to solve or improve the above-mentioned technical problems.

[0005] This application can be implemented as follows:

[0006] In one aspect, this application provides an ultrafine cementitious material, which, by weight, comprises 45-55 parts slag powder, 13-25 parts steel slag powder, 26-37 parts fly ash, and 0.05-0.2 parts solubilizing and activating agent.

[0007] The solubilizing activator contains at least one of the following: phytic acid, alcohol polymers, glycosyl biosurfactants, and silicate compounds.

[0008] In an optional embodiment, the solubilizing activator contains phytic acid, alcohol polymers, glycosyl biosurfactants, and silicate compounds in a mass ratio of (9-20):(1-5):(1-5):(0.1-1).

[0009] In an optional embodiment, the phytic acid includes at least one of pine acid and caffeic acid;

[0010] And / or, alcohol polymers include at least one of PVA and PVM;

[0011] And / or, glycosyl biosurfactants include at least one of octanol polyether sulfate, dodecyl polyether sulfate, and polysorbate ether sulfate;

[0012] And / or, silicate compounds include at least one of sodium silicate and aluminum silicate.

[0013] In an optional embodiment, the specific surface area of ​​the slag powder is 420-430 m². 2 / kg;

[0014] And / or, the specific surface area of ​​steel slag powder is 460-470 m². 2 / kg;

[0015] And / or, fly ash is classified as Grade 1 ash for power plants.

[0016] In an optional embodiment, the chemical composition of slag powder, steel slag powder, and fly ash each independently includes CaO, SiO2, Al2O3, Fe2O3, and MgO.

[0017] In an optional embodiment, the chemical composition of the slag powder includes 44-48% CaO, 22-26% SiO2, 12-16% Al2O3, 0.6-1% Fe2O3 and 10-14% MgO.

[0018] And / or, the chemical composition of steel slag powder includes 40-44% CaO, 16-20% SiO2, 3-6% Al2O3, 18-22% Fe2O3 and 8-12% MgO;

[0019] And / or, the chemical composition of fly ash includes 9-14% CaO, 50-56% SiO2, 20-26% Al2O3, 3-6% Fe2O3 and 1-4% MgO.

[0020] In an optional embodiment, the density of the slag powder is 2.6-3.2 kg / m³. 3 ; and / or, the density of steel slag powder is 3-3.6 kg / m³. 3 ; and / or, the density of fly ash is 2-2.6 kg / m³ 3 .

[0021] In an optional embodiment, the specific surface area of ​​the ultrafine cementitious material is 720-740 m². 2 / kg;

[0022] The 7-day activity of ultrafine cementitious materials is 78-88%;

[0023] The 28-day activity of ultrafine cementitious materials is 98-115%.

[0024] Secondly, this application provides a method for preparing an ultrafine cementitious material as described in any of the foregoing embodiments, comprising the following steps: mixing and grinding the raw materials in proportion.

[0025] In an optional embodiment, slag powder, steel slag powder and fly ash are mixed, crushed, pretreated and ground, and then a solubilizing and activating agent is added for ultrafine grinding.

[0026] In an optional embodiment, the pretreatment grinding time is 8-12 min, and / or the ultrafine grinding time is 18-22 min.

[0027] Thirdly, this application provides an application of an ultrafine cementitious material as described in any of the foregoing embodiments, wherein the ultrafine cementitious material is used in building materials or roadbed materials.

[0028] In optional embodiments, the ultrafine cementitious material is used in coastal defense wave-damping twisted blocks, road concrete, or non-structural concrete.

[0029] The beneficial effects of this application include:

[0030] This application obtains an ultrafine cementitious material by combining slag powder, steel slag powder, fly ash, and a solubilizing activator in a specific ratio. The resulting ultrafine cementitious material has good and long-lasting cementitious activity and high compressive strength. This ultrafine cementitious material can effectively recycle solid waste, which is beneficial for reducing costs and protecting the environment. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 The image shows the SEM image of the cement paste obtained in Comparative Example 1 after hydration for 28 days.

[0033] Figure 2 The image shows the SEM image of the cement paste obtained in Comparative Example 2 after hydration for 28 days.

[0034] Figure 3 for Figure 2 Enlarged view of part of the image;

[0035] Figure 4 The image shows the SEM image of the cement paste obtained in Example 1 of the experimental case after hydration for 28 days. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0037] The following provides a detailed description of the ultrafine cementitious material provided in this application, its preparation method, and its application.

[0038] This application proposes an ultrafine cementitious material, the raw materials of which, by weight, include 45-55 parts slag powder, 13-25 parts steel slag powder, 26-37 parts fly ash, and 0.05-0.2 parts solubilizing and activating agent.

[0039] For reference, the amount of slag powder can be 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts or 55 parts, or any other value within the range of 45-55 parts.

[0040] The amount of steel slag powder can be 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25 parts, or any other value within the range of 13-25 parts.

[0041] The amount of fly ash can be 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36 or 37 parts, or any other value within the range of 26-37 parts.

[0042] The amount of solubilizing activator can be 0.05 parts, 0.08 parts, 0.1 parts, 0.12 parts, 0.15 parts, 0.18 parts or 0.2 parts, or any other value within the range of 0.05-0.2 parts.

[0043] The ternary system composed of slag powder, steel slag powder, and fly ash fully leverages the composite synergistic effect of the raw materials. Slag powder provides high activity, while the spherical glassy particles in fly ash can act as ball bearings to improve the fluidity and water retention of the mixture. Steel slag powder is hard and mainly serves as a grinding medium to grind other powders.

[0044] It should be noted that if the amount of slag powder is less than 45 parts, it is detrimental to the activity of the entire ternary system; the more slag powder used, the higher the activity index of the ternary system, but if the amount of slag powder is more than 55 parts, it will affect the later strength. If the amount of steel slag powder is less than 13 parts, its role as a grinding medium will be reduced; steel slag powder helps to improve the early activity index, but if the amount of steel slag powder is more than 25 parts, it is detrimental to the later activity index. If the amount of fly ash is less than 26 parts, it is detrimental to the fluidity and water retention of the mixture; if the amount of fly ash is more than 37 parts, it is detrimental to the later strength and durability of the cementitious material.

[0045] In some embodiments, the raw materials for the ultrafine cementitious material include 50 parts slag powder, 20 parts steel slag powder, 30 parts fly ash, and 0.1 parts solubilizing activator. Under this ratio, the ultrafine cementitious material can achieve better results.

[0046] In this application, the slag powder, also known as granulated blast furnace slag powder, contains CaO, SiO2, Al2O3, Fe2O3, and MgO in its chemical composition.

[0047] In some embodiments, the chemical composition of the slag powder includes 44-48% CaO, 22-26% SiO2, 12-16% Al2O3, 0.6-1% Fe2O3, and 10-14% MgO. In some specific embodiments, the chemical composition of the slag powder includes 45.56% CaO, 23.69% SiO2, 13.37% Al2O3, 0.86% Fe2O3, 11.52% MgO, and 0.23% loss on ignition.

[0048] In some embodiments, the density of the slag powder is 2.6-3.2 kg / m³. 3 In some specific implementations, the density of the slag powder is 2.95 kg / m³. 3 .

[0049] By controlling the density within the above range, the pores inside the cementitious material can be smaller and fewer, resulting in a denser structure that is beneficial for improving the strength of the cementitious material. The same principle applies to steel slag powder and fly ash.

[0050] In some embodiments, the specific surface area of ​​the slag powder is 420-430 m². 2 / kg. In some specific embodiments, the specific surface area of ​​the slag powder is 425m². 2 / kg.

[0051] By controlling the specific surface area within the above range, the contact area between particles and water can be increased during the hydration reaction to accelerate the reaction, thereby improving the gel activity of industrial solid waste. The same applies to steel slag powder and fly ash.

[0052] In some typical implementations, the slag powder is S95 grade ore powder.

[0053] In this application, the chemical composition of steel slag powder mainly contains CaO and SiO2, with the remainder including Al2O3, Fe2O3, and MgO.

[0054] In some embodiments, the chemical composition of the steel slag powder includes 40-44% CaO, 16-20% SiO2, 3-6% Al2O3, 18-22% Fe2O3, and 8-12% MgO. In some specific embodiments, the chemical composition of the steel slag powder includes 41.46% CaO, 17.46% SiO2, 4.67% Al2O3, 20.58% Fe2O3, 10.83% MgO, and 1.35% loss on ignition.

[0055] In some embodiments, the density of steel slag powder is 3-3.6 kg / m³. 3 In some specific implementations, the density of the steel slag powder is 3.36 kg / m³. 3 .

[0056] In some embodiments, the specific surface area of ​​the steel slag powder is 460-470 m². 2 / kg. In some specific embodiments, the specific surface area of ​​the steel slag powder is 465m². 2 / kg.

[0057] In this application, the chemical composition of fly ash mainly includes CaO, SiO2 and Al2O3, and also contains Fe2O3 and MgO, and may further contain alkali metal oxides (such as sodium oxide and potassium oxide).

[0058] In some embodiments, the chemical composition of fly ash includes 9-14% CaO, 50-56% SiO2, 20-26% Al2O3, 3-6% Fe2O3, and 1-4% MgO, further including 1-4 wt% Na2O and 1.02-2.14% K2O. In some specific embodiments, the chemical composition of fly ash includes 10.11% CaO, 52.32% SiO2, 22.41% Al2O3, 4.3% Fe2O3, 1.56% MgO, and 4.23% loss on ignition.

[0059] In some implementations, the density of fly ash is 2-2.6 kg / m³. 3 In some specific implementations, the density of fly ash is 2.36 kg / m³. 3 .

[0060] In some implementations, the fly ash is Class 1 ash from power plants.

[0061] Continuing from the above, by combining slag powder, steel slag powder and fly ash, the chemical components can play an activating role. For example, alkali metal compounds can activate SiO2 and Al2O3, promoting the formation of aluminum-oxygen-silicate tetrahedral three-dimensional network polymers, which in turn helps to improve the activity and mechanical properties of ultrafine cementitious materials.

[0062] In this application, the solubilizing activator contains at least one of phytic acid, alcohol polymers, glycosyl biosurfactants, and silicate compounds.

[0063] By using solubilizing and activating agents, the silicon-oxygen tetrahedra and aluminum-oxygen tetrahedra in the glassy matrix of industrial solid waste can be depolymerized into H3SiO4. - and H3AlO4 2- When Ca is present in the hydrated slurry 2+ OH － It can also accelerate the hydration reaction, generating hydration products such as CSH (calcium silicate hydrate) gel and AFt (ettringite). Among them, CSH gel is the main source of strength of solid waste cementitious materials, while AFt plays an important role in the early setting and hardening of solid waste cementitious materials.

[0064] In some preferred embodiments, the solubilizing activator contains phytic acid, alcohol polymers, glycosyl biosurfactants, and silicate compounds, which can achieve a more prominent solubilizing and activating effect and improve the strength of the ultrafine cementitious material.

[0065] For example, the mass ratio of phytic acid, alcohol polymers, glycosyl biosurfactants, and silicate compounds can be (9-20):(1-5):(1-5):(0.1-1), such as 9:1:1:0.1, 9:1:1:0.5, 9:1:1:1, 9:1:2:0.1, 9:1:2:0.5, 9:1:2:1, 9:1:3:0.1, 9:1:3:0.5, 9:1:3:1, 9:1:4:0.1, 9:1:4:0.5, 9:1:4:1, 9:1:5:0.1, 9:1:5:0.5, 9:1:5:1, 9:2:1:0.1, 9:2:1:0.5, 9:2:1:1, 9:2:2:0.1. 9:2:2:0.5, 9:2:2:1, 9:2:3:0.1, 9:2:3:0.5, 9:2:3:1, 9:2:4:0.1, 9:2:4:0.5, 9:2:4:1, 9:2:5:0.1, 9:2:5:0.5, 9:2:5:1, 9:3:1:0.1, 9:3:1:0.5, 9: 3:1:1, 9:3:2:0.1, 9:3:2:0.5, 9:3:2:1, 9:3:3:0.1, 9:3:3:0.5, 9:3:3:1, 9:3:4:0.1, 9:3:4:0.5, 9:3:4:1, 9:3:5:0.1, 9:3:5:0.5, 9:3:5:1, 9:4:1:0 1, 9:4:1:0.5, 9:4:1:1, 9:4:2:0.1, 9:4:2:0.5, 9:4:2:1, 9:4:3:0.1, 9:4:3:0.5, 9:4:3:1, 9:4:4:0.1, 9:4:4:0.5, 9:4:4:1, 9:4:5:0.1, 9:4:5:0.5 9:4:5:1, 9:5:1:0.1, 9:5:1:0.5, 9:5:1:1, 9:5:2:0.1, 9:5:2:0.5, 9:5:2:1, 9:5:3:0.1, 9:5:3:0.5, 9:5:3:1, 9:5:4:0.1, 9:5:4:0.5, 9:5:4:1, 9:5: 5:0.1, 9:5:5:0.5, 9:5:5:1, 15:1:1:0.1, 15:1:1:0.5, 15:1:1:1, 15:1:2:0.1, 15:1:2:0.5, 15:1:2:1, 15:1:3:0.1, 15:1:3:0.5, 15:1:3:1, 15:1:4:0 1, 15:1:4:0.5, 15:1:4:1, 15:1:5:0.1, 15:1:5:0.5, 15:1:5:1, 15:2:1:0.1, 15:2:1:0.5, 15:2:1:1, 15:2:2:0.1, 15:2:2:0.5, 15:2:2:1, 15:2:3:0.1、15:2:3:0.5、15:2:3:1、15:2:4:0.1、15:2:4:0.5、15:2:4:1、15:2:5:0.1、15:2:5:0.5、15:2:5:1、15:3:1:0.1、15:3:1:0.5、15:3:1:1、15:3:2:0.1、15:3:2:0.5、15:3:2:1、15:3:3:0.1、15:3:3:0.5、15:3:3:1、15:3:4:0.1、15:3:4:0.5、15:3:4:1、15:3:5:0.1、15:3:5:0.5、15:3:5:1、15:4:1:0.1、15:4:1:0.5、15:4:1:1、15:4:2:0.1、15:4:2:0.5、15:4:2:1、15:4:3:0.1、15:4:3:0.5、15:4:3:1、15:4:4:0.1、15:4:4:0.5、15:4:4:1、15:4:5:0.1、15:4:5:0.5、15:4:5:1、15:5:1:0.1、15:5:1:0.5、15:5:1:1、15:5:2:0.1、15:5:2:0.5、15:5:2:1、15:5:3:0.1、15:5:3:0.5、15:5:3:1、15:5:4:0.1、15:5:4:0.5、15:5:4:1、15:5:5:0.1、15:5:5:0.5、15:5:5:1；20:1:1:0.1、20:1:1:0.5、20:1:1:1、20:1:2:0.1、20:1:2:0.5、20:1:2:1、20:1:3:0.1、20:1:3:0.5、20:1:3:1、20:1:4:0.1、20:1:4:0.5、20:1:4:1、20:1:5:0.1、20:1:5:0.5、20:1:5:1、20:2:1:0.1、20:2:1:0.5、20:2:1:1、20:2:2:0.1、20:2:2:0.5、20:2:2:1、20:2:3:0.1、20:2:3:0.5、20:2:3:1、20:2:4:0.1、20:2:4:0.5、20:2:4:1、20:2:5:0.1、20:2:5:0.5、20:2:5:1、20:3:1:0.1、20:3:1:0.5、20:3:1:1、20:3:2:0.1、20:3:2:0.5、20:3:2:1、20:3:3:0.1、20:3:3:0.5、20:3:3:1、20:3:4:0.1、20:3:4:0.5、20:3:4:1、20:3:5:0.1, 20:3:5:0.5, 20:3:5:1, 20:4:1:0.1, 20:4:1:0.5, 20:4:1:1, 20:4:2:0.1, 20:4:2:0.5, 20:4:2:1, 20:4:3:0.1, 20:4:3:0.5, 20:4:3:1, 20:4:4:0.1, 20:4:4:0.5, 20:4:4:1, 20:4:5:0.1, 20:4:5:0.5, 20:4:5:1, 20:5:1:0. 1. The possible values ​​are 20:5:1:0.5, 20:5:1:1, 20:5:2:0.1, 20:5:2:0.5, 20:5:2:1, 20:5:3:0.1, 20:5:3:0.5, 20:5:3:1, 20:5:4:0.1, 20:5:4:0.5, 20:5:4:1, 20:5:5:0.1, 20:5:5:0.5, or 20:5:5:1, etc., or any other value within the range (9-20):(1-5):(1-5):(0.1-1).

[0066] The main function of phytic acid is to enhance the activity of materials such as slag and steel slag, promoting their gelation and hardening processes. Insufficient dosage will not fully activate these materials, leading to incomplete gelation and affecting the strength and hardening speed of the cementitious material. Excessive dosage may result in an overly acidic environment, potentially causing excessive dissolution of some components in the slag and steel slag, disrupting the material's stability and gelation reaction, and ultimately leading to a decline in the performance of the ultrafine cementitious material.

[0067] Alcohols are primarily used to maintain the dispersion of cementitious materials. Insufficient dosage may lead to particle aggregation, reducing the performance of ultrafine cementitious materials. Excessive dosage may result in over-dispersion of the material, weakening the interaction between particles and making it difficult to form a solid cementitious material.

[0068] Insufficient amounts of glycosyl biosurfactants may lead to the aggregation of ultrafine particles, reducing the homogeneity of the gelling material. Excessive amounts can easily cause over-dispersion of the material, weakening the interaction between particles, potentially increasing viscosity and making it difficult to form a solid gelling material.

[0069] Silicate compounds primarily act as coagulants during the gelation process, helping to improve the gel strength of the material. Insufficient dosage can lead to incomplete hardening, affecting the material's strength and durability. Excessive dosage may cause over-gelation, preventing the sufficient formation of hydration products, resulting in reduced material strength and performance.

[0070] Optionally, the aforementioned plant acids may include, for example, at least one of pine acid and caffeic acid. Alcoholic polymers may include, for example, at least one of PVA and PVM. Glycosyl biosurfactants may include, for example, at least one of octyl ether sulfate, dodecyl ether sulfate, and polysorbate ether sulfate. Silicate compounds may include, for example, at least one of sodium silicate and aluminum silicate.

[0071] The density of the above-mentioned solubilizing activator can be 1.05-1.26 g / cm³. 3 .

[0072] In some embodiments, the specific surface area of ​​the ultrafine cementitious material provided in this application is 720-740 m². 2 / kg. In some embodiments, the 7-day activity of the ultrafine cementitious material provided in this application is 78-88%, and the 28-day activity is 98-115%.

[0073] In other words, the ultrafine cementitious material provided in this application has good and long-lasting cementitious activity, and the ultrafine cementitious material has low porosity, low total pore surface area, high density, and high compressive strength.

[0074] Accordingly, this application also provides a method for preparing an ultrafine cementitious material as described in any of the foregoing embodiments, comprising the following steps: mixing and grinding the raw materials in proportion.

[0075] In some implementations, all raw materials can be mixed and ground in one go.

[0076] In some preferred embodiments, slag powder, steel slag powder and fly ash are first mixed, crushed, pretreated and ground, and then a solubilizing and activating agent is added for ultrafine grinding.

[0077] The pretreatment grinding time can be 8-12 minutes, such as 8 minutes, 9 minutes, 10 minutes, 11 minutes, or 12 minutes. The ultrafine grinding time can be 48-52 minutes, such as 48 minutes, 49 minutes, 50 minutes, 51 minutes, or 52 minutes.

[0078] The above-mentioned pre-treatment grinding not only allows for the pre-treatment grinding of difficult-to-grind raw materials, but also enables the synergistic grinding of various raw materials together. Subsequently, the materials are placed in an ultrafine mill for ultrafine grinding under the action of a solubilizing and activating agent, which can achieve better grinding results with lower power consumption.

[0079] It should be noted that this application utilizes physical grinding to improve the activity of cementitious materials from solid wastes such as slag, steel slag, and fly ash. Specifically, combining pre-treatment grinding with ultrafine grinding achieves physical activation (mechanical activation). Mechanical force disrupts the material surface, reduces particle size, alters crystal structure and surface physicochemical properties, and distorts the mineral's crystal structure, decreasing crystallinity and gradually leading to lattice dislocations, defects, and recrystallization. The SiO2 and Al2O3 contained in the raw materials become soluble, forming an amorphous form coated on the particle surface that is easily soluble in water, allowing water molecules to more easily penetrate and accelerate hydration reactions. This, in turn, improves the cementitious activity of industrial solid waste.

[0080] The ultrafine grinding process described in this application mainly aims to grind the material to a fineness of 720-740 μm. 2 While the grinding efficiency is high, ultrafine grinding consumes a significant amount of energy. Therefore, this application addresses this issue by pre-grinding the materials to reduce their specific surface area to a certain fineness, ensuring thorough mixing, and then adding them to the ultrafine mill, thereby improving grinding efficiency and effect. Furthermore, since different materials have varying grindability, directly ultrafine grinding all materials would not yield optimal grinding results.

[0081] In addition, this application also provides an application of the ultrafine cementitious material as described in any of the foregoing embodiments, for example, it can be used in building materials or roadbed materials.

[0082] For reference, this ultrafine cementitious material can be used as a concrete admixture or aggregate in building materials. For example, it can be used in coastal defense wave-damping slabs, road concrete, or non-structural concrete.

[0083] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0084] Example 1

[0085] This embodiment provides an ultrafine cementitious material, which is obtained by first mixing and crushing 50 parts of slag powder, 20 parts of steel slag powder and 30 parts of fly ash, pre-treating and grinding for 10 minutes, then adding 0.1 parts of solubilizing and activating agent, and ultra-fine grinding for 50 minutes.

[0086] The slag powder is S95 slag powder (compliant with GB / T18046-2000). The chemical composition of the slag powder includes 45.56% CaO, 23.69% SiO2, 13.37% Al2O3, 0.86% Fe2O3, 11.52% MgO, and 0.23% loss on ignition. The density of the slag powder is 2.95 kg / m³. 3 Specific surface area is 425 m² 2 / kg, with 78% activity after 7 days and 98% activity after 28 days.

[0087] The steel slag powder is Grade I steel slag powder (compliant with GB / T20491-2017). The chemical composition of the steel slag powder includes 41.46% CaO, 17.46% SiO2, 4.67% Al2O3, 20.58% Fe2O3, 10.83% MgO, and 1.35% loss on ignition. The density of the steel slag powder is 3.36 kg / m³. 3 Specific surface area is 465m² 2 / kg, with 70% activity after 7 days and 81% activity after 28 days.

[0088] Fly ash is classified as Grade 1 power plant ash (compliant with GB / T1596-2017). The chemical composition of fly ash includes 10.11% CaO, 52.32% SiO2, 22.41% Al2O3, 4.3% Fe2O3, 1.56% MgO, and 4.23% loss on ignition. The density of fly ash is 2.36 kg / m³. 3 The activity was 56% after 7 days and 72% after 28 days.

[0089] The solubilizing activator contains red pinnatifida acid, PVA, dodecyl alcohol polyether sulfate, and sodium silicate in a mass ratio of 10:3:3:0.5. The density of the solubilizing activator is 1.26 g / cm³. 3 .

[0090] The grinding mill used for pretreatment grinding was a 305×350 dry intermittent experimental ball mill, and the grinding mill used for ultrafine grinding was a model SM-500×500.

[0091] Example 2

[0092] The difference between this embodiment and Embodiment 1 is that the ultrafine cementitious material is composed of 45 parts slag powder, 25 parts steel slag powder, 30 parts fly ash and 0.05 parts solubilizing and activating agent.

[0093] Example 3

[0094] The difference between this embodiment and Embodiment 1 is that the ultrafine cementitious material is composed of 55 parts slag powder, 13 parts steel slag powder, 32 parts fly ash, and 0.2 parts solubilizing and activating agent.

[0095] Example 4

[0096] The difference between this embodiment and Embodiment 1 is that the ultrafine cementitious material is composed of 49 parts slag powder, 25 parts steel slag powder, 26 parts fly ash, and 0.2 parts solubilizing and activating agent.

[0097] Example 5

[0098] The difference between this embodiment and Embodiment 1 is that the ultrafine cementitious material is composed of 53 parts slag powder, 10 parts steel slag powder, 37 parts fly ash, and 0.2 parts solubilizing and activating agent.

[0099] Example 6

[0100] The difference between this embodiment and Embodiment 1 is that the mass ratio of red pinnatifida acid, PVA, dodecyl alcohol polyether sulfate, and sodium silicate is 9:1:1:0.1.

[0101] Example 7

[0102] The difference between this embodiment and Embodiment 1 is that the mass ratio of red pinnatifida acid, PVA, dodecyl alcohol polyether sulfate, and sodium silicate is 20:5:5:1.

[0103] Example 8

[0104] The difference between this embodiment and Example 1 is that: the plant acid is caffeic acid, the alcohol polymer is PVM, the glycosyl biosurfactant is octanol polyether sulfate, and the silicate compound is aluminum silicate.

[0105] The settings of Comparative Examples 1-7 and their differences from Example 1 are shown in Table 1.

[0106] Table 1. Formula (per serving)

[0107]

[0108] Comparative Example 8

[0109] The difference between this comparative example and Example 1 is that the solubilizing activator is composed of red pinoxadenic acid and PVA in a mass ratio of 1:1.

[0110] Comparative Example 9

[0111] The difference between this comparative example and Example 1 is that the solubilizing agent is composed of dodecyl alcohol polyether sulfate and sodium silicate in a mass ratio of 1:1.

[0112] Comparative Example 10

[0113] The difference between this comparative example and Example 1 is that the amount of solubilizing activator used is 0.02 parts.

[0114] Comparative Example 11

[0115] The difference between this comparative example and Example 1 is that the amount of solubilizing activator used is 0.5 parts.

[0116] Comparative Example 12

[0117] The difference between this comparative example and Example 1 is that the mass ratio of red pinnatifida acid, PVA, dodecyl alcohol polyether sulfate, and sodium silicate is 5:10:10:2.

[0118] Comparative Example 13

[0119] The difference between this comparative example and Example 1 is that all raw materials were not pre-treated and ground, but were directly subjected to ball ultrafine grinding.

[0120] Comparative Example 14

[0121] The difference between this comparative example and Example 1 is that the slag powder, steel slag powder, and fly ash are mixed, crushed, pre-treated, and ground, and then a solubilizing and activating agent is added for ordinary ball milling. The specific surface area of ​​the material after ball milling does not exceed 700 m². 2 / kg.

[0122] Test case

[0123] The ultrafine cementitious materials of each embodiment and comparative example were added to the cement matrix at a weight of 50 wt%. The cement matrix was composed of standard sand and cement in a mass ratio of 1:3.

[0124] The standard sand used was produced in Xiamen. The cement was Conch P·O 42.5 ordinary Portland cement. The specific surface area of ​​the cement was 362 m². 2 / kg, density is 3.18kg / m³ 3 The loss on ignition was 3.7%, the 3-day compressive strength was 25.6 MPa, the 7-day compressive strength was 40.2 MPa, and the 28-day compressive strength was 54.7 MPa.

[0125] ① The activity, specific surface area, and density of the ultrafine cementitious materials obtained in Comparative Examples 1-8 and Comparative Examples 1-14 are shown in Table 2.

[0126] Table 2 Comparison Results

[0127]

[0128]

[0129] ② Compare the particle size distribution of the ultrafine cementitious materials obtained in Comparative Examples 1-4. The results are shown in Table 3.

[0130] Table 3 Comparison Results

[0131]

[0132] ③ The particle size distribution of the ultrafine cementitious materials obtained in Comparative Example 1 and Comparative Example 2 is shown in Table 4.

[0133] Table 4 Comparison Results

[0134]

[0135]

[0136] ④ The cement pastes obtained from Comparative Example 1 and Comparative Example 2 were subjected to structural tests after 28 days of hydration. The results are as follows: Figure 1 and Figure 2 As shown.

[0137] The microstructure of the cement paste hardened over 28 days revealed that the hydration products of the blank mineral powder sample (Comparative Example 1) were mainly flocculent CSH, with a relatively loose structure and only partial cross-linking to form a network structure. In contrast, the hydration products of Comparative Example 2 exhibited more CSH gel phase, which was evenly distributed and cross-linked, resulting in a denser overall structure. This indicates a higher degree of hydration, and the overall density of the hydration products was higher than that of Comparative Example 1.

[0138] ⑤ The cement pastes obtained in Comparative Example 2 and Example 1 were subjected to structural tests after 28 days of hydration. The results are as follows: Figure 3 and Figure 4 As shown, where, Figure 3 for Figure 2 A magnified view of a portion of the image.

[0139] Depend on Figure 3 It can be seen that the particles in Comparative Example 2 exhibit dissolution on their surface and agglomeration due to uneven distribution. However, they can effectively fill the gaps between hydration products. Utilizing their adsorption properties and small specific surface area, a secondary hydration reaction occurs in the gaps, which increases the density of the matrix structure and effectively fills the pores.

[0140] Depend on Figure 4 As can be seen, in Example 1, the addition of 0.1% solubilizing and activating agent caused the particles and hydration products to connect with each other and form a layered stack. The agglomerated ultrafine solid waste cementitious material was dispersed and embedded in the matrix structure, refining the cement pores and resulting in a higher density and lower porosity of the pore structure.

[0141] ⑥ The pore structure of the products obtained in Comparative Example 2 and Example 1 was tested using the mercury intrusion porosimetry method, and the results are shown in Table 5.

[0142] Table 5 Test Results

[0143] Porosity (%) <![CDATA[Total pore surface area (m 2 / g)]]> Comparative Example 2 12.3 25.23 Example 1 10.4 22.79

[0144] As can be seen from Table 5, after adding the solubilizing and activating agent, the porosity and total pore surface area of ​​the product showed a decreasing trend, indicating that the density of the cement-based material improved, resulting in better mechanical properties. The role of ultrafine cementitious materials in the overall system during the later stage of hydration is not only physical filling, but also secondary chemical hydration reaction. The fineness decreases, the filling effect improves, and it is more conducive to the development of compressive strength and volume stability.

[0145] In summary, the ultrafine cementitious material provided in this application has good and long-lasting cementitious activity. Furthermore, the ultrafine cementitious material has low porosity, low total pore surface area, high density, and high compressive strength. It can replace the method of using only S95 grade mineral powder in building materials or roadbed materials, which is conducive to reducing costs and provides a new way to dispose of solid waste such as steel slag.

[0146] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ultrafine cementitious material, characterized in that, By weight, the raw materials of the ultrafine cementitious material include 45-55 parts slag powder, 13-25 parts steel slag powder, 26-37 parts fly ash, and 0.05-0.2 parts solubilizing and activating agent; The solubilizing activator contains phytic acid, a polymer, a surfactant, and a silicate compound in a mass ratio of (9-20):(1-5):(1-5):(0.1-1); the phytic acid is selected from at least one of pine acid and caffeic acid; the polymer is selected from at least one of PVA and PVM; the surfactant is selected from at least one of octanol polyether sulfate, dodecyl polyether sulfate, and polysorbate ether sulfate; and the silicate compound is selected from at least one of sodium silicate and aluminum silicate. The preparation of the ultrafine cementitious material includes the following steps: mixing and crushing the slag powder, steel slag powder and fly ash in proportion, pre-treating and grinding, then adding the solubilizing and activating agent, and ultra-fine grinding; the pre-treatment grinding time is 8-12 min, and the ultra-fine grinding time is 48-52 min; The specific surface area of ​​the ultrafine cementitious material is 720-740 m². 2 / kg.

2. The ultrafine cementitious material according to claim 1, characterized in that, The specific surface area of ​​the slag powder is 420-430 m². 2 / kg; And / or, the specific surface area of ​​the steel slag powder is 460-470 m². 2 / kg; And / or, the fly ash is Class 1 fly ash from a power plant.

3. The ultrafine cementitious material according to claim 1, characterized in that, The chemical composition of the slag powder, the steel slag powder, and the fly ash all independently includes CaO, SiO2, Al2O3, Fe2O3, and MgO.

4. The ultrafine cementitious material according to claim 3, characterized in that, The chemical composition of the slag powder includes 44-48% CaO, 22-26% SiO2, 12-16% Al2O3, 0.6-1% Fe2O3 and 10-14% MgO. And / or, the chemical composition of the steel slag powder includes 40-44% CaO, 16-20% SiO2, 3-6% Al2O3, 18-22% Fe2O3 and 8-12% MgO; And / or, the chemical composition of the fly ash includes 9-14% CaO, 50-56% SiO2, 20-26% Al2O3, 3-6% Fe2O3 and 1-4% MgO.

5. The ultrafine cementitious material according to claim 1, characterized in that, The 7-day activity of the ultrafine cementitious material is 78-88%; The 28-day activity of the ultrafine cementitious material is 98-115%.

6. A method for preparing an ultrafine cementitious material as described in any one of claims 1-5, characterized in that, Includes the following steps: The slag powder, steel slag powder and fly ash are mixed and crushed in proportion, pretreated and ground, and then the solubilizing and activating agent is added for ultrafine grinding; the pretreatment grinding time is 8-12 minutes and the ultrafine grinding time is 48-52 minutes.

7. An application of the ultrafine cementitious material as described in any one of claims 1-5, characterized in that, The ultrafine cementitious material is used in building materials or roadbed materials.

8. The application according to claim 7, characterized in that, The ultrafine cementitious material is used in coastal defense wave-damping twisted blocks, road concrete, or non-structural concrete.

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