Calculation method for reaction degree of each component in ordinary Portland cement-slag system

Abstract

The invention discloses a method for calculating the reaction degree of each component in an ordinary Portland cement-slag system, and belongs to the field of concrete materials.The method comprises the steps that ordinary Portland cement-slag mixed slurry is prepared; obtaining a characteristic element distribution diagram by utilizing electronic probe micro-area analysis; the method comprises the following steps: sequentially performing image recognition and segmentation on unreacted fly ash particles, unhydrated tetracalcium aluminoferrite clinker, unhydrated alite and belite clinker (through calcium-rich phase screening and theoretical silicon-calcium ratio judgment) and unreacted slag particles on the basis of element characteristics of each phase of an ordinary Portland cement-slag system; by calculating the volume fraction of the unreacted particles and combining the initial mix proportion and the material density of the system, the reaction degrees of the components such as the cement and the slag are finally and accurately quantified. According to the invention, accurate quantification of the reaction degree of each component in the ordinary Portland cement-slag system is realized.

Description

Technical Field

[0001] This invention relates to the field of concrete materials, and in particular to a method for calculating the degree of reaction of each component in a common silicate cement-slag system. Background Technology

[0002] Finely ground blast furnace slag, rich in amorphous alumina and silica, exhibits reactivity similar to natural volcanic ash. Using it as an auxiliary cementitious material to partially replace cement can not only effectively reduce carbon emissions during cement production but also optimize the microstructure of cementitious materials, significantly improving resistance to sulfate attack and carbonation. According to current standards, 6%–20% of slag and fly ash are permitted as active admixtures in ordinary Portland cement, forming a cement-slag-fly ash ternary composite system. However, due to the significant differences in the hydration reaction rates of cement clinker, slag, and fly ash, this system typically forms a heterogeneous microstructure containing unreacted particles after hardening. Furthermore, the interactions between the components during hydration further increase the complexity of the system's reaction behavior. Therefore, there is an urgent need to establish a method that can accurately quantify the degree of reaction of each component to scientifically assess its hydration process.

[0003] Currently, commonly used methods for determining the degree of reaction of slag or fly ash in mixed systems mainly include selective solvent dissolution and backscattered electron imaging (BSE-IA). Selective solvent dissolution uses specific chemical solvents to selectively dissolve hydration products and unhydrated cement, retaining unreacted slag or fly ash particles, thus achieving quantitative analysis. For example, EDTA-NaOH solution is used to determine the degree of slag reaction, or hydrochloric acid treatment is used to assess the reaction state of fly ash. Backscattered electron imaging relies on scanning electron microscopy to identify and statistically analyze different phases based on grayscale differences in the image, thereby calculating the degree of reaction of each component.

[0004] However, the above methods have significant limitations in the application of ternary composite systems. Selective dissolution methods are difficult to effectively distinguish between slag and fly ash because their dissolution process lacks component specificity, making it impossible to independently quantify the degree of reaction of the three components. In addition, the solvent's dissolution of hydration products and unhydrated cement is often incomplete, easily introducing significant errors. Although backscattered electron image analysis has multiphase recognition capabilities, the overlapping grayscale value ranges of slag, fly ash, cement clinker, and some hydration products (such as calcium hydroxide, calcium aluminate silicate, etc.) make image segmentation difficult, severely affecting the accuracy of unreacted particle identification, and thus also failing to achieve precise quantification of the degree of reaction of each component. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for calculating the degree of reaction of each component in a common silicate cement-slag system. By obtaining the volume fraction of unreacted particles and the initial volume fraction of each component in the mixed system, the degree of reaction of each component is finally obtained.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for calculating the degree of reaction of each component in a common silicate cement-slag system includes the following steps:

[0008] Step 1: Preparation of ordinary Portland cement-slag mixed slurry: The raw materials include cementitious materials and water, wherein the cementitious materials include ordinary Portland cement and slag;

[0009] Step 2: Obtaining elemental distribution images: Samples were taken from the ordinary silicate cement-slag mixed slurry and processed to meet the requirements of microscopic testing. The samples were observed using an electron probe microanalysis device to obtain elemental distribution images of aluminum, magnesium, calcium, silicon, titanium, manganese, sulfur, oxygen, iron, chlorine, sodium, and potassium.

[0010] Step 3: Segmentation of unreacted particles:

[0011] Image segmentation of unreacted fly ash particles in slurry was performed using the characteristic element distribution map of fly ash.

[0012] Image segmentation of unhydrated tetracalcium aluminoferrite clinker in slurry was performed using the characteristic element distribution map of tetracalcium aluminoferrite.

[0013] The calcium-rich phase in the slurry was screened using the elemental distribution map of calcium, and the unhydrated alite and alite clinker in the slurry were image segmented using the theoretical silica-calcium ratio of belite.

[0014] Image segmentation of unreacted slag particles in slurry is performed using the characteristic element distribution map of slag.

[0015] Step 4: Quantify the degree of reaction: Use image processing software to count the area of ​​the separated unreacted particles. Based on the total area of ​​the slurry region, obtain the area fraction of unreacted particles in the slurry region. According to the principle of stereochemistry, the area fraction of a certain substance in an isotropic cement-based material is equal to its volume fraction. Based on the mixing ratio of the mixed system and the density of the raw materials, obtain the initial volume fraction of each component in the cement-based material. Finally, the degree of reaction of each component can be calculated.

[0016] A further improvement of the technical solution of the present invention is that: in step 1, the water-cement ratio of the ordinary silicate cement-slag mixed slurry is 0.4, and the slag content is 20%.

[0017] A further improvement to the technical solution of this invention is as follows: In step 2, the sample preparation process is as follows: ordinary silicate cement and slag are added to a mixer and premixed for 2 minutes; then, water is poured into the mixer and stirred for another 2 minutes to obtain a uniformly mixed ordinary silicate cement-slag slurry; after mixing, the fresh slurry is poured into a 40mm×40mm×40mm cubic mold; the mold is wrapped with plastic film to reduce moisture evaporation and cured at room temperature for 24 hours; finally, the slurry is demolded and placed in a constant temperature and humidity curing chamber at a temperature of 22±2℃ and a relative humidity of >98% for 14 days. When the curing period reaches 14 days, a cubic sample with a size of approximately 1cm×1cm×1cm is cut from the center of the cubic sample.

[0018] A further improvement to the technical solution of the present invention is that, in step 2, the sample processing procedure is as follows:

[0019] The sample was immersed in isopropanol to terminate the hydration reaction;

[0020] The residual isopropanol in the test block was removed using a vacuum drying oven;

[0021] After the sample is cooled to room temperature, it is impregnated with low-viscosity epoxy resin to fix the microstructure of the test surface.

[0022] After the resin has fully cured, the sample surface is finely polished with oil-based diamond powder and then ultrasonically cleaned in anhydrous ethanol.

[0023] Finally, carbon spraying is performed on the test surface of the sample to enhance conductivity.

[0024] A further improvement to the technical solution of this invention is as follows: In step 2, the observation of the sample using an electron probe microanalyzer specifically includes: elemental concentration distribution analysis using a JEOL JXA-8230 electron probe microanalyzer, with test conditions set as follows: accelerating voltage 15kV, beam current 50nA; observing the sample test surface using the backscatter mode of the electron probe at 750x magnification, with a field of view of 160μm×120μm; setting the EPMA scan step size to 0.4μm and the single-point scan time to 30ms; quantitatively analyzing the chemical element distribution in the sample by analyzing the wavelength and intensity of characteristic X-rays, and converting the measured X-ray intensity into the mass percentage of each element by establishing a calibration curve using standard samples; the obtained concentration distribution map of each element consists of 400×300 pixels.

[0025] A further improvement of the technical solution of the present invention is that: in step 3, aluminum, silicon and oxygen are selected as feature elements to segment unreacted fly ash particles, and a grayscale image of the normalized concentration sum of the three elements is obtained by using image processing software, and unreacted fly ash particles are segmented by grayscale thresholding.

[0026] Iron, aluminum, and calcium were selected as feature elements to segment unreacted tetracalcium aluminoferrite. Based on the position of the already segmented fly ash particles, fly ash particles were removed from the grayscale image of the normalized total concentration distribution of calcium, aluminum, and iron. Tetracalcium aluminoferrite was then segmented by grayscale thresholding.

[0027] Calcium was selected as the characteristic element, and the positions of fly ash particles and tetracalcium aluminoferrite were removed from the Ca element distribution map. The calcium-rich area was segmented by gray scale threshold, and then the molar ratio of silicon and calcium was calculated in this area. Alite and belite clinker were segmented by using the theoretical silicon-calcium ratio of 0.33 of belite as the threshold. Finally, the segmentation results of cement clinker including tetracalcium aluminoferrite, alite and belite were obtained.

[0028] Calcium, silicon, aluminum, and magnesium were selected as feature elements to segment unreacted slag particles. Based on the positions of the already segmented fly ash particles and cement clinker, fly ash particles and cement clinker were removed from the grayscale image of the normalized sum of concentrations of calcium, aluminum, silicon, and magnesium. Unreacted slag particles were then segmented through grayscale thresholding.

[0029] A further improvement of the technical solution of the present invention is that the method for normalizing the feature element distribution map is as follows: the element concentration value of each pixel is divided by the element concentration threshold of the image in which it is located, so that the element concentration values ​​of different feature elements are normalized to a similar range, which facilitates the subsequent concentration matrix summation operation.

[0030] A further improvement of the technical solution of the present invention is that, in step 4, according to the principle of stereochemistry, the two-dimensional area fraction in the ordinary silicate cement-slag mixed slurry can be regarded as the true volume fraction in the three-dimensional slurry.

[0031] The technological advancements achieved by this invention due to the adoption of the above technical solutions are as follows:

[0032] This invention addresses the problem of accurately segmenting unreacted particles in ordinary silicate cement-slag systems. By applying the chemical element concentration distribution image of the mixed system, multiple unreacted particles are accurately segmented based on multi-element characteristic elements, ultimately obtaining accurate results of the reaction degree of each component. This achieves particle segmentation of ternary mixed systems, more accurately quantifies the content of unreacted particles in the mixed system, and thus quantifies a more accurate degree of reaction. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a distribution image of Al elements in the slurry region in an embodiment of the present invention;

[0035] Figure 2 This is a distribution image of Mg elements in the slurry region in an embodiment of the present invention;

[0036] Figure 3 This is a distribution image of Ca elements in the slurry region in an embodiment of the present invention;

[0037] Figure 4 This is a distribution image of Si elements in the slurry region in an embodiment of the present invention;

[0038] Figure 5 This is a distribution image of Ti elements in the slurry region in an embodiment of the present invention;

[0039] Figure 6 This is a distribution image of Mn elements in the slurry region in an embodiment of the present invention;

[0040] Figure 7 This is a distribution image of S element in the slurry region in an embodiment of the present invention;

[0041] Figure 8 This is a distribution image of O elements in the slurry region in an embodiment of the present invention;

[0042] Figure 9 This is a distribution image of Fe elements in the slurry region in an embodiment of the present invention;

[0043] Figure 10 This is a distribution image of Cl elements in the slurry region in an embodiment of the present invention;

[0044] Figure 11 This is a distribution image of Na elements in the slurry region in an embodiment of the present invention;

[0045] Figure 12 This is a distribution image of K element in the slurry region in an embodiment of the present invention;

[0046] Figure 13 This is a distribution image of the sum of silicon, aluminum and oxygen content in the slurry region in an embodiment of the present invention;

[0047] Figure 14 This is an image of unreacted fly ash particles after segmentation in an embodiment of the present invention;

[0048] Figure 15 This is a distribution image of the sum of iron, aluminum and calcium content in the slurry region in an embodiment of the present invention;

[0049] Figure 16 This is an image of the unreacted tetracalcium aluminoferrite clinker after segmentation in an embodiment of the present invention;

[0050] Figure 17 This is a segmented image of the calcium-rich phase in the slurry region in an embodiment of the present invention;

[0051] Figure 18 This is a visualization image of the molar ratio of silicon and calcium elements at the calcium-rich phase position in an embodiment of the present invention;

[0052] Figure 19 These are images of Alite and Belite clinker segmented after removing calcium hydroxide and calcium carbonate in this embodiment of the invention.

[0053] Figure 20 These are images of all unreacted cement clinker segmented in this embodiment of the invention;

[0054] Figure 21 This is a distribution image of the sum of calcium, aluminum, silicon and magnesium content in the slurry region in an embodiment of the present invention;

[0055] Figure 22 This is an image of unreacted slag particles after segmentation in an embodiment of the present invention;

[0056] Figure 23 This is an image of all unreacted particles segmented from the slurry region in this embodiment of the invention. Detailed Implementation

[0057] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product or device.

[0058] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0059] Example

[0060] A method for calculating the degree of reaction of each component in a common silicate cement-slag system, specifically including the following:

[0061] 1. Raw materials and test plan

[0062] 1.1 Raw materials

[0063] In this embodiment, the water-cement ratio of the ordinary Portland cement-slag mixed slurry is 0.4, and the slag content is 20%. The raw materials include cementitious materials and water; the cementitious materials include P·O42.5 type ordinary Portland cement and S95 grade slag, both with densities of 3.13 g / cm³. 3 and 3.10 g / cm 3 The chemical composition and loss on ignition of both are shown in Table 1. Ordinary Portland cement contains 12% admixture (7% fly ash and 5% slag). The slag used as admixture is the same as the added slag, and the density of the fly ash is 2.55 g / cm³. 3 .

[0064] Table 1 Chemical composition (wt%) of ordinary Portland cement and slag

[0065]

[0066]

[0067] 1.2 Sample Preparation

[0068] This embodiment uses ordinary Portland cement-slag mixed cement paste. The specific preparation process is as follows: Ordinary Portland cement and slag are added to a mixer and premixed for 2 minutes; then, water is poured into the mixer and mixed for another 2 minutes to obtain a uniformly mixed ordinary Portland cement-slag mixed paste. After mixing, the fresh paste is poured into a 40mm×40mm×40mm cubic mold. The mold is wrapped with plastic film to reduce moisture evaporation and cured at room temperature for 24 hours. Finally, the paste is demolded and placed in a constant temperature and humidity curing chamber (temperature 22±2℃, relative humidity >98%) for 14 days. After 14 days of curing, a cubic sample with a size of approximately 1cm×1cm×1cm is cut from the center of the cubic sample.

[0069] 1.3 Test Methods

[0070] The sample was immersed in isopropanol to terminate the hydration reaction. Residual isopropanol was removed from the sample using a vacuum drying oven. After cooling to room temperature, the sample was impregnated with low-viscosity epoxy resin to fix the microstructure of the test surface. After the resin had completely cured, the sample surface was finely polished with oil-based diamond powder and ultrasonically cleaned in anhydrous ethanol. Finally, carbon spraying was performed on the test surface of the sample to enhance conductivity.

[0071] Elemental concentration distribution analysis was performed using a JEOL JXA-8230 electron probe microanalyzer. Test conditions were set as follows: accelerating voltage 15 kV, beam current 50 nA. The sample surface was observed at 750x magnification using the electron probe microanalyzer's backscatter mode, with a field of view of 160 μm × 120 μm. The EPMA scan step size was set to 0.4 μm, and the single-point scan time to 30 ms. The chemical element distribution in the sample was quantitatively analyzed by analyzing the wavelength and intensity of characteristic X-rays. A calibration curve was established using standard samples to convert the measured X-ray intensity into the mass percentage of each element. Each elemental concentration distribution map consisted of 400 × 300 pixels. Considering the elemental composition of each phase in the mixed slurry, 12 elements were analyzed in the sample, including Al, Mg, Ca, Si, Ti, Mn, S, O, Fe, Cl, Na, and K, in the following order: Figures 1-12 As shown.

[0072] 2. Test Results

[0073] 2.1 Segmentation of Unreacted Particles

[0074] Figures 1-12 The figure shows the distribution of 12 elements in the same area of ​​ordinary silicate cement-slag mixed paste. The numbers next to the color scale in the figure correspond to the X-ray count for each color, and the count reflects the relative content of the element.

[0075] from Figures 1-12 As can be seen, the content of aluminum (Al), silicon (Si), and oxygen (O) elements is the highest in fly ash particles. Image processing software was used to process the distribution map of silicon (Si), aluminum (Al), and oxygen (O) elements in the slurry region of the mixed system, obtaining a grayscale image of the normalized total concentration distribution of silicon (Si), aluminum (Al), and oxygen (O) elements in this region, as shown in the image. Figure 13 . Figure 13 The higher the grayscale value (the brighter the image), the higher the relative abundance of these three elements. Figure 13 As can be seen, unreacted fly ash particles appear distinctly bright white. By using grayscale thresholding, unreacted fly ash particles can be separated. Figure 14 This displays the unreacted fly ash particles segmented after grayscale thresholding. To avoid affecting subsequent particle segmentation, the positions of the segmented unreacted fly ash particles in the corresponding elemental distribution map are removed.

[0076] Given that cement clinker contains multiple mineral phases, such as allit, belite, tricalcium aluminate, and tetracalcium aluminoferrite, the tricalcium aluminate is essentially consumed after 1-3 days of curing, leaving mainly the other three clinker phases. Figures 1-12The data shows that tetracalcium aluminoferrite in cement clinker is rich in calcium (Ca), aluminum (Al), and iron (Fe). These three elements can be used as characteristic elements to segment tetracalcium aluminoferrite. Based on the location of the segmented fly ash particles, fly ash particles are removed from the grayscale image of the normalized sum of the concentrations of calcium (Ca), aluminum (Al), and iron (Fe). (See...) Figure 15 Tetracalcium aluminoferrite was segmented using a grayscale thresholding method, see [link / reference]. Figure 16 After the cement clinker is segmented, its position on the corresponding elemental distribution map is removed to avoid affecting the subsequent slag particle segmentation.

[0077] from Figures 1-12 The graph shows that allite and belite in cement clinker are rich in calcium. First, the calcium-rich areas are segmented based on Ca content. Then, the locations of fly ash particles and tetracalcium aluminoferrite are removed from the Ca distribution map. Figure 17 The calcium-rich region is segmented using a grayscale threshold, and then the molar ratio of silicon to calcium is calculated within this region. Figure 18 Alite and Alite clinker were separated using the theoretical silicon-to-calcium ratio of 0.33 as the threshold. Figure 19 The final fractionation results of the cement clinker (including tetracalcium aluminoferrite, allit, and belite) are shown in [reference needed]. Figure 20 .

[0078] from Figures 1-12 The data shows that calcium (Ca), aluminum (Al), silicon (Si), and magnesium (Mg) are the most abundant elements in the slag, and these four elements are characteristic elements of unreacted slag particles. Based on the positions of the separated fly ash particles and cement clinker, fly ash particles and cement clinker were removed from the grayscale image of the normalized sum of concentrations of calcium, aluminum, silicon, and magnesium. (See attached image.) Figure 21 Unreacted slag particles were segmented using a grayscale threshold, see... Figure 22 The distribution of unreacted fly ash particles, cement clinker, and slag particles is combined, see [the diagram]. Figure 23 .

[0079] 2.2 Degree of Reaction

[0080] according to Figure 14 , Figure 20 and Figure 22The area fraction of each unreacted particle within the observation area can be calculated using the image processing software ImageJ. At a magnification of 750×, a sufficient number of slurry regions were selected for microstructural observation and image processing to meet statistical requirements. The area fractions of unhydrated cement, unreacted slag particles, and unreacted fly ash particles were found to be 13.57%, 4.34%, and 2.63%, respectively. Based on stereochemical principles, the two-dimensional area fraction in the ordinary Portland cement-slag mixture slurry can be considered as the true volume fraction in the three-dimensional slurry. The initial volume fraction of each component can be obtained based on the mix proportion and raw material density of the ordinary Portland cement-slag mixture slurry. Finally, the degree of reaction of each component is obtained, as shown in Table 2 below.

[0081] Table 2. Reactivity degree (%) of each component in ordinary Portland cement-slag mixed paste

[0082]

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the degree of reaction of each component in a common silicate cement-slag system, characterized in that, Includes the following steps: Step 1: Preparation of ordinary Portland cement-slag mixed slurry: The raw materials include cementitious materials and water, wherein the cementitious materials include ordinary Portland cement and slag; Step 2: Obtaining elemental distribution images: Samples were taken from the ordinary silicate cement-slag mixed slurry and processed to meet the requirements of microscopic testing. The samples were observed using an electron probe microanalysis device to obtain elemental distribution images of aluminum, magnesium, calcium, silicon, titanium, manganese, sulfur, oxygen, iron, chlorine, sodium, and potassium. Step 3: Segmentation of unreacted particles: Image segmentation of unreacted fly ash particles in slurry was performed using the characteristic element distribution map of fly ash. Image segmentation of unhydrated tetracalcium aluminoferrite clinker in slurry was performed using the characteristic element distribution map of tetracalcium aluminoferrite. The calcium-rich phase in the slurry was screened using the elemental distribution map of calcium, and the unhydrated alite and alite clinker in the slurry were image segmented using the theoretical silica-calcium ratio of belite. Image segmentation of unreacted slag particles in slurry is performed using the characteristic element distribution map of slag. Step 4: Quantify the degree of reaction: Use image processing software to count the area of ​​the separated unreacted particles. Based on the total area of ​​the slurry region, obtain the area fraction of unreacted particles in the slurry region. According to the principle of stereochemistry, the area fraction of a certain substance in an isotropic cement-based material is equal to its volume fraction. Based on the mix proportion of the mixed system and the density of the raw materials, obtain the initial volume fraction of each component in the cement-based material. Finally, the degree of reaction of each component can be calculated.

2. The method for calculating the degree of reaction of each component in a common silicate cement-slag system according to claim 1, characterized in that, In step 1, the water-cement ratio of the ordinary silicate cement-slag mixture is 0.4, and the slag content is 20%.

3. The method for calculating the degree of reaction of each component in a common silicate cement-slag system according to claim 1, characterized in that, In step 2, the sample preparation process is as follows: ordinary silicate cement and slag are added to a mixer and premixed for 2 minutes; then, water is poured into the mixer and stirred for another 2 minutes to obtain a uniformly mixed ordinary silicate cement-slag slurry; after mixing, the fresh slurry is poured into a 40mm×40mm×40mm cubic mold. Wrap the mold with plastic film to reduce moisture evaporation and cure at room temperature for 24 hours. Finally, demold the slurry and place it in a constant temperature and humidity curing chamber at 22±2℃ and relative humidity >98% for 14 days. When the curing period reaches 14 days, cut a cube sample with a size of about 1cm×1cm×1cm from the center of the cube sample.

4. The method for calculating the degree of reaction of each component in a common silicate cement-slag system according to claim 3, characterized in that, In step 2, the sample processing procedure is as follows: The sample was immersed in isopropanol to terminate the hydration reaction; The residual isopropanol in the test block was removed using a vacuum drying oven; After the sample is cooled to room temperature, it is impregnated with low-viscosity epoxy resin to fix the microstructure of the test surface. After the resin has fully cured, the sample surface is finely polished with oil-based diamond powder and then ultrasonically cleaned in anhydrous ethanol. Finally, carbon spraying is performed on the test surface of the sample to enhance conductivity.

5. The method for calculating the degree of reaction of each component in a common silicate cement-slag system according to claim 1, characterized in that, In step 2, the observation of the sample using an electron probe microanalysis specifically includes: elemental concentration distribution analysis using a JEOL JXA-8230 electron probe microanalysis instrument, with test conditions set as follows: accelerating voltage 15kV, beam current 50nA; observing the sample test surface using the backscatter mode of the electron probe at 750x magnification, with a field of view of 160μm×120μm; setting the EPMA scan step size to 0.4μm and the single-point scan time to 30ms; quantitatively analyzing the chemical element distribution in the sample by analyzing the wavelength and intensity of characteristic X-rays, and converting the measured X-ray intensity into the mass percentage of each element by establishing a calibration curve using standard samples; the resulting concentration distribution map of each element consists of 400×300 pixels.

6. The method for calculating the degree of reaction of each component in a common silicate cement-slag system according to claim 1, characterized in that, In step 3, aluminum, silicon and oxygen are selected as feature elements to segment unreacted fly ash particles. Image processing software is used to obtain a grayscale image of the normalized sum of the concentrations of the three elements, and unreacted fly ash particles are segmented by grayscale thresholding. Iron, aluminum, and calcium were selected as feature elements to segment unreacted tetracalcium aluminoferrite. Based on the position of the already segmented fly ash particles, fly ash particles were removed from the grayscale image of the normalized total concentration distribution of calcium, aluminum, and iron. Tetracalcium aluminoferrite was then segmented by grayscale thresholding. Calcium was selected as the characteristic element, and the positions of fly ash particles and tetracalcium aluminoferrite were removed from the Ca element distribution map. The calcium-rich area was segmented by gray scale threshold, and then the molar ratio of silicon and calcium was calculated in this area. Alite and belite clinker were segmented by using the theoretical silicon-calcium ratio of 0.33 of belite as the threshold. Finally, the segmentation results of cement clinker including tetracalcium aluminoferrite, alite and belite were obtained. Calcium, silicon, aluminum, and magnesium were selected as feature elements to segment unreacted slag particles. Based on the positions of the already segmented fly ash particles and cement clinker, fly ash particles and cement clinker were removed from the grayscale image of the normalized sum of concentrations of calcium, aluminum, silicon, and magnesium. Unreacted slag particles were then segmented through grayscale thresholding.

7. The method for calculating the degree of reaction of each component in a common silicate cement-slag system according to claim 6, characterized in that, The method for normalizing the feature element distribution map is as follows: divide the element concentration value of each pixel by the element concentration threshold of its image, so that the element concentration values ​​of different feature elements are normalized to a similar range, which facilitates the subsequent concentration matrix summation operation.

8. The method for calculating the degree of reaction of each component in a common silicate cement-slag system according to claim 1, characterized in that, In step 4, based on the principle of stereochemistry, the two-dimensional area fraction in the ordinary silicate cement-slag mixture can be regarded as the true volume fraction in the three-dimensional mixture.

Images