Methods of analyzing auxiliary cementitious materials (SCMs) and predicting behavior of SCMs in cementitious mixtures

Abstract

A method of analyzing an auxiliary cementitious material (SCM) may include obtaining a sample comprising the SCM; immersing the sample in an alkaline or acidic aqueous solution, thereby subjecting the sample to dissolution; determining the ion concentration in the alkaline or acidic aqueous solution for a predetermined time after the sample is immersed; and predicting reactivity of the SCM in the gelling mixture based on the ion concentration. In another embodiment, a method of analyzing SCM may include obtaining a sample including SCM; placing the sample on a porous substrate in contact with a water source; measuring a change in water level of the water source as the sample absorbs water passing through the porous substrate; and determining the water absorbency of the sample. The hydroscopicity may predict yield stress and / or viscosity of a gelling mixture including the SCM.

Description

[0001] Related applications

[0002] This patent document claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 538,623, filed September 15, 2023, which is incorporated herein by reference in its entirety.

[0003] Federally funded research or development

[0004] This invention was completed with government support under DE-AR0001401 granted by the Advanced Research Projects Agency-Energy (ARPA-E) of the U.S. Department of Energy. The government holds certain rights to this invention. Technical Field

[0005] This invention generally relates to the analysis of auxiliary cementitious materials (SCM), and more specifically to a method for rapidly analyzing SCMs, such as clay, under pristine or activated conditions, and predicting their performance in cementitious mixtures. Background Technology

[0006] Globally, over four billion tons of cement are produced annually, accounting for 6-8% of CO2 emissions. Replacing some of the clinker in cement with supplemental cementitious materials (SCMs) is the most successful strategy for reducing CO2 emissions in the global cement industry. However, the limited supply of conventional SCMs makes further implementation of this strategy difficult unless new types of SCMs become available. One type of material available to meet the required quantity is clay, which can be calcined to produce effective SCMs. For use in building materials, a certain level of reactivity is required to promote the development of material strength. Clay calcined at 700-850°C exhibits optimal reactivity in cementitious mixtures, but transforms into a less reactive crystalline phase when calcined at higher temperatures. In industrial-scale production, clay can be derived from various sources, contains different mineral compositions, undergoes different calcination temperatures, has different particle sizes due to grinding, and / or can be subjected to mechanochemical activation, all of which contribute to variations in reactivity. Evaluation of reactivity is beneficial for quality control of clay activation. However, current reactivity testing is time- and labor-intensive. For example, ASTM C1897 R... 3 The method requires up to 7 days of testing time and well-trained technicians.

[0007] The presence of clay in a cementitious mixture alters its rheology. Furthermore, calcination temperature affects the physical hygroscopicity of clay and directly influences the rheology (or processability) of the cementitious mixture. Using clay as a SCM increases the water requirement for the desired processability, to a degree dependent on its composition, particle size, and calcination temperature. Therefore, it is beneficial to quantitatively determine the rheological properties of clays to ensure their suitability for practical applications. The current ASTM standard C1749 for rheology applies to pure cementitious systems and is extremely sensitive to sample preparation. Implementation of ASTM C1749 requires meticulous training to minimize the variability of results, particularly for SCMs such as reactive clays. Summary of the Invention

[0008] This disclosure describes methods for analyzing auxiliary cementitious materials (SCMs) and predicting the behavior of SCMs in cementitious mixtures.

[0009] According to one embodiment, a method for analyzing SCM includes: obtaining a sample containing SCM; immersing the sample in an alkaline or acidic aqueous solution, thereby causing the sample to dissolve; determining the ion concentration in the alkaline or acidic aqueous solution at a predetermined time after immersion of the sample; and predicting the reactivity of SCM in the gel mixture based on the ion concentration.

[0010] According to another embodiment, a method for analyzing SCM includes: obtaining a sample containing SCM; placing the sample on a porous substrate in contact with a water source; measuring the water level change of the water source as the sample absorbs water through the porous substrate; and determining the water absorbency of the sample, the water absorbency predicting the yield stress and viscosity of the gel mixture containing SCM.

[0011] A method for predicting the behavior of clay in a cementitious mixture includes: after activation, obtaining one or more samples from clay material, each sample containing activated clay, said one or more samples comprising or divided into first and second samples; at predetermined times, determining the concentrations of silicon ions and aluminum ions in corresponding first and second batches of alkaline or acidic aqueous solutions containing the first sample; determining the water absorption of the second sample; predicting the reactivity of the activated clay in the cementitious mixture based on the concentrations of silicon and aluminum ions; predicting the yield stress and / or viscosity of the cementitious mixture containing the activated clay based on the water absorption; and adjusting the activation conditions of the clay if the predicted reactivity, yield stress, and / or viscosity are not optimal. Attached Figure Description

[0012] Figure 1 This is a schematic diagram illustrating an example of a continuous calcination process followed by the collection of calcined clay samples.

[0013] Figure 2Two colorimetric analysis methods are described for determining the ion concentration of calcined clay or other SCM samples after immersion in an alkaline aqueous solution.

[0014] Figure 3 A-3C illustrates the dissolution of an exemplary calcined clay sample, followed by optional filtration and dilution steps.

[0015] Figures 4A-4C Exemplary steps in SCM analysis are shown, including obtaining multiple batches of alkaline aqueous solutions, adding one or more chemicals (or colorants) to each batch, and performing colorimetric analysis using UV-Vis spectroscopy or photographic image analysis.

[0016] Figure 4D and 4E The calibration method for ultraviolet-visible spectroscopy and photographic image analysis is shown.

[0017] Figure 5 Data for numerous clay samples were plotted, showing ion concentration results obtained using the rapid analytical method of this disclosure and R values ​​obtained according to ASTM C1897. 3 Strong correlation between cumulative heat results.

[0018] Figure 6A This describes a method for measuring the water absorption of calcined clay or other SCM samples.

[0019] Figure 6B An exemplary graph showing water absorption as a function of time is displayed.

[0020] Figure 6C and 6D A perspective view of an alternative device for measuring water absorption is shown.

[0021] Figure 7A Data from multiple samples were plotted, demonstrating a strong correlation between the absorption results obtained using the rapid analytical methods of this disclosure and the yield stress of cement, cement / fly ash blends, and cement / clay blends as measured by a rheometer.

[0022] Figure 7B Data from multiple samples were plotted, demonstrating a strong correlation between the absorption results obtained using the rapid analytical methods of this disclosure and the viscosity of cement, cement / fly ash blends, and cement / clay blends as measured by a rheometer.

[0023] Figures 8A-8C The cumulative heat release as a function of R, as measured by isothermal calorimetry, is shown for high-grade kaolinite, Na-montmorillonite, and 70 / 30 illite / montmorillonite mixed layers. 3 The evolution of test duration.

[0024] Figure 8D The cumulative exothermic reaction over seven days is shown for samples calcined at 400–1000 °C; uncalcined samples are plotted at 25 °C.

[0025] Figures 9A-9C The figures show the aluminum (Al) concentration, silicon (Si) concentration, and Si / Al ratio during the dissolution of uncalcined high-grade kaolinite and high-grade kaolinite calcined at different temperatures in 4M NaOH solution at 90°C. The x-axis in all figures represents time (minutes).

[0026] Figures 10A-10C The figures show the Al concentration, Si concentration, and Si / Al ratio during the dissolution of uncalcined Na-montmorillonite and Na-montmorillonite calcined at different temperatures in 4M NaOH solution at 90°C. The x-axis in all figures represents time (minutes).

[0027] Figure 11A-11C The figures show the Al concentration, Si concentration, and Si / Al ratio during the dissolution of 70 / 30 illite / montmorillonite mixed layers (uncalcined at 70 / 30) and 70 / 30 illite / montmorillonite calcined at different temperatures in 4M NaOH solution at 90°C. The x-axis in all figures represents time (minutes).

[0028] Figure 12A and 12B The correlation between Al and Si concentrations, as determined using camera image analysis and a UV-Vis spectrophotometer, is shown.

[0029] Figures 13A-13C The 7-day cumulative Rg of high-grade kaolinite, Na-montmorillonite, and 70 / 30 illite / montmorillonite mixed layers calcined at different temperatures is shown. 3 Correlation between heat and dissolved Al concentration at 1–15 minutes.

[0030] Figure 13D Showing Figures 13A-13C The R-squared value of the correlation in (R) 2 ).

[0031] Figures 14A-14C The 7-day cumulative Rg from high-grade kaolinite, Na-montmorillonite, and 70 / 30 illite / montmorillonite mixed layers calcined at different temperatures is shown. 3 Correlation between heat and dissolved Si concentration at 1–15 minutes; uncalcined samples plotted at 25 °C.

[0032] Figure 14D Show Figure 12A-1 R of correlation in 2C 2 .

[0033] Figures 15A-15CThe 7-day cumulative Rc values ​​are shown for high-grade kaolinite, Na-montmorillonite, and 70 / 30 illite / montmorillonite mixed layers calcined at different temperatures, and for commercial metakaolinite samples C1-C5. 3 Correlation between heat and the concentrations of Al, Si, and the dissolution mass of Al2O3 and SiO2 within 5 minutes; uncalcined samples plotted at 25°C. Error bars show the standard error between repeated trials.

[0034] Figure 16A The 7-day cumulative Rg from high-grade kaolinite, Na-montmorillonite, and 70 / 30 illite / montmorillonite mixed layers calcined at different temperatures is shown. 3 The correlation between heat and the solubility index (1.54 times the Al concentration plus the Si concentration) was plotted for the uncalcined sample at 25°C. Error bars show the standard error between repeated trials.

[0035] Figure 16B The correlations after adding natural clay N1-N17 are shown.

[0036] Figure 16C Showing 7d cumulative R 3 The correlation between heat and the index (1.54 Al + Si) is calculated by subtracting the dissolved Al and Si from the dissolved Al and Si in the uncalcined sample using the Al and Si concentrations of the calcined sample. For commercial metakaolinite, the dissolved Al and Si in the uncalcined high-grade kaolinite are subtracted.

[0037] Figure 17 The UR described in this disclosure is shown 2 The applicability of the method to another type of SCM, fly ash. For various fly ash samples, the dissolved Al concentration at 15 minutes of dissolution was multiplied by a factor of 0.4 and added to the dissolved Si concentration at 15 minutes of dissolution to form the 15-minute UR. 2 The solubility index was calculated, and its relationship with 7-day R was shown. 3 Relevance of results.

[0038] Detailed Implementation Plan

[0039] As mentioned above, activated clay is an important auxiliary cementitious material (SCM) for meeting the growing demands of the cement industry and reducing its carbon footprint. (Reference) Figure 1This paper explains a real-time method for predicting the behavior of clay and other solid precipitates (SCMs) in cementitious mixtures during industrial production processes. In addition to unactivated and activated (e.g., calcined) clays, this method is applicable to SCMs such as fly ash, silica fume, recycled ash, ground granular blast furnace slag, non-ferrous slag, steel slag, copper slag, natural volcanic ash, ash from agricultural waste, waste-to-energy ash, waste glass, bauxite residue, limestone, zeolite, and / or filler materials. The concentrations of the major elements present in each SCM, measured by the rapid dissolution of the SCM, and their water absorption capacity can be key factors in determining their performance. The term "cementitious mixture" or "cementitious mixture including SCMs" can be understood as referring to a mixture that may include some or all of the following components: one or more SCMs, cement, cement clinker, water, and / or (one or more) other additives. In some instances, the cementitious mixture may contain concrete.

[0040] It should be understood that activated clay can be prepared by thermal activation (e.g., heating or calcination), mechanical activation, and / or mechanochemical activation of clay minerals such as hydrous layered aluminosilicates, which include alumina, silica, and possibly other phases. Calcination is particularly important in... Figure 1 The following is an explanation and discussion. Mechanical or mechanochemical activation can be understood as requiring the use of mechanical energy (e.g., grinding) to induce the activation of clay minerals. During activation (e.g., thermal, mechanochemical), hydroxyl groups (OH) are released from the clay minerals, forming water. After structural changes due to dehydroxylation, Al₂O₃ and SiO₂ in the activated clay may become reactive; the degree of reactivity can depend on, for example, calcination temperature or mechanochemical activation conditions (e.g., grinding time). (Reactive Al₂O₃ and SiO₂ can contribute to the formation of calcium aluminosilicate hydrates during the pozzolanic reaction of activated clay in cementitious mixtures, which can refine the microstructure and improve the mechanical strength of activated clay-blended cementitious materials. Therefore, reactivity is a key aspect in determining the suitability of activated clay for use in cementitious mixtures.) Clay may comprise many mineral phases in varying mass percentages, such as any one of kaolinite, montmorillonite, illite, and / or saponite. Low-grade clays containing, for example, less than 20% kaolinite can be obtained from natural minerals and waste sediments in various locations and may contain several mineral phases and other components. The low homogeneity of such clay sources makes real-time reactivity monitoring advantageous if the separation of non-reactive, moderately reactive, and highly reactive activated clays is not required.

[0041] refer to Figure 1The method includes obtaining a sample 102 comprising SCM for analysis. In some instances, sample 102 may be obtained from clay mass 104 after calcination has occurred, for example, after being continuously conveyed through the heating zone 106a of kiln 106. Figure 1 As shown in the diagram. Typically, the industrial-scale calcination step occurs in a kiln calciner or a flash calciner. In this disclosure, reference to a kiln can be understood to refer to any of these calciners. It is understood that the clay material 104 includes clay minerals. In the kiln 106, the clay material 104 may be exposed to a high temperature (e.g., calcination temperature) for a residence time, which is determined by the rate at which the clay material 104 is conveyed through the heating zone 106a. Figure 1 As shown, clay material 104 can be conveyed through kiln 106 using conveyor belt 108. In other instances, clay material 104 can be exposed to elevated temperatures in a batch process, for example, clay material 104 can be placed in a furnace for calcination. Alternatively, sample 102 can be obtained from clay material 104 after grinding or other mechanochemical activation has occurred. In some examples, sample 102 can be obtained from raw (unactivated) clay material prior to processing, for example, directly from a quarry or clay mine. It is also contemplated that sample 102 can be obtained after co-grinding or mixing with one or more other materials such as cement, limestone, or gypsum. If sample 102 comprises non-clay SCM as described above, the sample can be obtained from a quarry, agricultural, or industrial source. Typically, sample 102 can be in the form of powder, granules, agglomerates, and / or pellets.

[0042] As described above, in some instances, sample 102 can be obtained after calcination (or, more generally, after activation), or in real time during a continuous process, or after a batch process is completed. Figure 1In the example shown, after the clay material 104 leaves the heating zone 106a of the kiln 106, the sample 102 falls into the collection container 112 through the opening 110 in the conveyor belt 108 under gravity. Alternatively, other collection strategies can be used to obtain the sample 102. Multiple samples 102 can be obtained from the clay material 104 and / or a single sample 102 can be separated into multiple samples 102 for analysis. The amount of sample 102 required for the rapid dissolution and water absorption analysis described below is typically less than 500 g, less than 200 g, less than 100 g, less than 50 g, less than 20 g, less than 10 g, less than 5 g, less than 2 g, or less than 1 g, and / or as low as 0.1 g, as low as 0.01 g, or as low as 0.001 g, for example, 0.1 g to 0.5 g or 0.1 g to 0.3 g. The analysis can be performed in a short time so that calcination or activation conditions (e.g., increased temperature, residence time, grinding time, etc.) can be modified online as needed. For example, ion concentration and absorption analysis can each be performed in 15 minutes or less, 5 minutes or less, or even 2 minutes or less.

[0043] First, a rapid dissolution analysis method is described. For example... Figure 1 As shown, once sample 102 is obtained, for example, from clay material 104, it can typically be immersed in an alkaline aqueous solution 114 at a temperature of 25°C–100°C or 60°C–95°C. The alkaline aqueous solution 114 may include an alkali, such as sodium hydroxide (NaOH), potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, and / or lithium carbonate, and water. In one example, the alkaline aqueous solution contains a 4M NaOH solution. In other examples, an acidic aqueous solution containing hydrochloric acid, nitric acid, and / or sulfuric acid may be used instead of the alkaline aqueous solution. Upon immersion, sample 102 begins to dissolve, as... Figure 2 As shown in the leftmost diagram.

[0044] It is of interest to determine the ion concentration in the alkaline or acidic aqueous solution 114 at a predetermined time or number of times after immersion of sample 102, because the dissolution rate is related to reactivity. The determination can be performed rapidly after immersion of sample 102, for example, within 60 minutes, 30 minutes, 15 minutes, 5 minutes, 2 minutes, or 1 minute. Ions of interest may include aluminum, silicon, calcium, sodium, potassium, magnesium, iron, and / or sulfur. Ion concentrations can be determined using suitable analytical techniques, such as colorimetric analysis, atomic adsorption spectroscopy, photoemission spectroscopy, mass spectrometry, titration, selective ion electrodes, precipitation, chromatography, fluorescence spectroscopy, and / or electrophoresis. In some instances, multiple batches of alkaline or acidic aqueous solutions are obtained, each batch containing dissolved sample and used to determine the concentrations of different ions. As described below, the clay dissolution results obtained according to the method described in this disclosure are consistent with those obtained using ASTM C1897 R 3The coagulation reactivity determined by isothermal calorimetry is consistent. Therefore, the concentration of one or more ions determined by rapid analytical methods can be used to predict the reactivity of SCM in gelling mixtures.

[0045] If correct Figure 3 As shown in the exemplary calcined clay sample in A, the method may further include filtration after dissolution and before colorimetric analysis or other analytical techniques. Figure 3 B) Dilution Figure 3 C) and / or acidify alkaline or acidic aqueous solutions or multiple batches of alkaline or acidic aqueous solutions.

[0046] Colorimetric analysis, such as Figure 2 and Figure 4C As shown, this is particularly important for determining ion concentrations. When preparing a colorimetric analysis, one or more chemicals 116, formulated to cause a color change in the presence of a specific ion of interest, can be added to an alkaline or acidic aqueous solution 114 (or to each batch of alkaline or acidic aqueous solution 114), such as... Figure 2 and Figure 4B As shown. One or more chemicals 116 or "coloring agents" may be selected from, for example, molybdates, chrome blue R, chrome azural S, fluorescent gallium reagent, 8-hydroxyquinoline, salicylaldehyde picolinoylhydrazone, morin, catechol violet, quercetin, test iron, aluminum reagent, and o-cresolphthalein complexone. In addition to the addition of one or more chemicals 116 to induce color change, pH buffers, reducing agents, and / or masking agents may be added to the alkaline or acidic aqueous solution 114. These can help control the pH of the alkaline or acidic aqueous solution, remove interference from other ions, and / or enhance color detection, and may be selected from hydrochloric acid, acetate, oxalic acid, amino-naphthol-sulfonic acid, and / or ascorbic acid. Figure 4C As illustrated in the diagram and described below, the intensity of color changes can be correlated with the concentration of a specific ion of interest using methods such as ultraviolet-visible spectroscopy or photographic image analysis.

[0047] In one instance, when two batches of alkaline or acidic aqueous solutions 114 are obtained and the concentrations of aluminum and silicon ions are to be determined, one or more chemicals 116 may include a first group of chemicals configured to cause a color change based on the presence of silicon ions and a second group of chemicals configured to cause a color change based on the presence of aluminum ions. The first group of chemicals (which may include a single chemical or multiple chemicals) may be added to one of the two batches of alkaline or acidic aqueous solutions, and the second group of chemicals (which may include a single chemical or multiple chemicals) may be added to the other of the two batches. To determine the silicon ion concentration, the first group of chemicals may be selected according to ASTM D859: Standard Test Method for Silica in Water. To determine the aluminum ion concentration, the second group of chemicals may be selected according to the 3500-Al B: Eriochrome Cyanine R Method.

[0048] As described above, colorimetric analysis can be performed using ultraviolet-visible spectroscopy. For ultraviolet-visible spectroscopy, the dissolved sample 102 can be irradiated with ultraviolet light and / or visible light, and the absorption spectrum 118 as a function of wavelength can be obtained using a spectrophotometer 120, such as... Figure 2 The lower path is shown. More typically, this method can be performed by measuring absorbance at a predetermined wavelength. For different ions, light absorption occurs at different wavelengths. In some instances, the wavelength corresponding to the maximum absorbance of the specific ion of interest is selected for analysis to ensure maximum sensitivity, but other wavelengths may also be suitable.

[0049] Before performing UV-Vis spectroscopy to determine the ion concentration in an alkaline or acidic aqueous solution 114, absorption spectra of a series of reference solutions with known ion concentrations can be obtained, such as... Figure 4D As shown, these can be used to construct a graph of absorbance versus concentration. A calibration curve can be created using a least-squares linear regression equation, and this equation can be used to determine the concentration of a specific ion of interest in an unknown sample based on the measured absorbance. Therefore, the concentration of a specific ion of interest (e.g., silicon and aluminum ions) can be determined based on the absorption spectrum 118 of sample 102.

[0050] Alternatively, colorimetric analysis can be performed using photographic image analysis. In this case, determining the ion concentration may require obtaining a photographic image of sample 102 using camera 122, such as... Figure 2The upper path is schematically shown, and the photographic image is converted to red-green-blue (RGB) format. Average luminance intensity values ​​for the red, green, and blue channels are obtained, and these average luminance intensity values ​​can be normalized to a range of 0 to 1. Using calibration data obtained from a reference solution with known ion concentrations, the concentration of ions (e.g., silicon and aluminum ions) in the alkaline or acidic aqueous solution 114 can be determined based on the normalized luminance intensity values. Colorimetric analysis is also anticipated to be performed via visual comparison (e.g., using the naked eye) between the alkaline or acidic aqueous solution 114 and the reference solution.

[0051] As discussed in the following examples, the reactivity of a range of uncalcined and calcined pure clays (kaolinite, montmorillonite, illite / montmorillonite mixed layers) and several commercially available calcined clays (a total of 25 different clays) was evaluated using isothermal calorimetry according to the ASTM C1897 standard method, and ion concentration data were obtained using rapid dissolution. Figure 5 The results shown reveal a strong correlation between the 7-day ASTM standard test and the 5-minute (in these examples) dissolution analysis method. A predetermined factor is applied (multiplied) to the Al concentration in μM and added to the Si concentration based on the enthalpy of dissolution of alumina and silica. For some clay samples, the predetermined factor can range from 1.1 to 1.7, or more preferably from 1.2 to 1.6, for example, about 1.5 or more specifically 1.54. For other SCMs, such as fly ash, the predetermined factor can be different, for example, in the range of 0.2 to 0.6, or more preferably 0.4. In some examples, the predetermined factor can be as low as zero. Therefore, the concentration of one or more ions determined as described in this disclosure can be used to predict the reactivity of clay or more generally SCMs in cementitious mixtures.

[0052] Furthermore, or alternatively, the method may also include predicting the processability (rheology) of the gelling mixture containing SCM. For example, as described below, the yield stress and / or viscosity of the gelling mixture (e.g., at room temperature (e.g., 18-22°C)) can be predicted based on the water absorption of the SCM. The sample 102 containing SCM can be obtained as described above, for example, by referring to... Figure 1 Once obtained, sample 102 can be positioned on porous substrate 124 in contact with water source 126, such as... Figure 6AAs shown. The porous substrate 124 may comprise filter paper or another porous material. A dropper 128, comprising a U-shaped curve and positioned horizontally at the same height as the filter paper 124, can be used to maintain the water supply. In one example, the dropper 128 may have a water capacity of 10 ml or more, with a graduation of 0.1 ml. The inner diameter of the dropper 128 defines the resolution of the water absorption capacity measurement. The porous substrate 124 with small pore sizes (e.g., 0.2 micrometers or less) can help avoid filtration of clay particles. A camera 122 may be placed near the dropper 128 to observe changes in water level when the sample 102 is placed on the filter paper 124. The amount of SCM used may vary between 0.1 g and 2 g or more. Smaller amounts may lead to inconsistencies due to mass measurement and sample placement, while larger amounts may increase the time required for water absorption.

[0053] When sample 102 absorbs water through filter paper or other porous substrate 124, the change in water level in water source 146 can be measured (e.g., using camera 122, as shown). More specifically, as sample 102 absorbs water, the water level in water source 146 decreases, and therefore the amount of water absorbed by sample 102 can be determined based on the measured decrease. Figure 6B An exemplary graph of water absorption as a function of time is shown. The water absorption of an SCM can be an indicator of its rheological properties in use, where a highly absorbent SCM has less water available for the flow of the gelling mixture. Therefore, water absorption can be an indicator of the need for superplasticizers to improve processability. Alternatively, the adsorption setting can be as follows: Figure 6C and 6D The modifications shown include adding a pump 129 to the system to automatically refill water from the reservoir at one end. Additionally, the dropper 128 can be modified to have a serpentine pattern while maintaining the same height, allowing multiple samples to be analyzed by manually or by refilling the dropper 128 with water once via the pump 129.

[0054] like Figures 7A-7B As shown, greater water absorption is associated with higher yield stress (or yield strength) and viscosity of cementitious mixtures that include SCMs (e.g., calcined clay). Rheological properties, such as yield stress and viscosity, can indicate fresh properties of concrete, such as microslump expansion, viscosity, filling capacity, flowability, pumpability, placement, disposal, and surface finishing. Figure 7A and 7BThe results shown were obtained from sixteen calcined clays (14 commercial clays and 2 kaolinite clays calcined at 600°C and 800°C, respectively), four IL-type Portland cements (OPC), and three fly ashes. In the case of calcined clays and fly ash, the rheological properties of the cement / SCM (80:20) blends were measured using a rheometer, while in the case of IL-type cement (water / binder ratio of 0.5), the rheological properties of 100% cement were measured using a rheometer. Figure 6A The device is used to measure water absorbency. In these embodiments, 0.7 μm filter paper is placed on a filter holder, which is connected to the dropper at the same horizontal arrangement as the filter paper, such as... Figure 6A As shown. The dropper can be a Kimex 51, with a capacity (10 ml) sufficient for a 0.3 g sample. Figure 6DAs shown, using longer droppers or improved geometry allows for the analysis of higher clay quantities. In this embodiment, the total measurement time was less than 3 minutes. It can be seen that the water requirement of the clay exhibits a strong correlation with the yield stress and viscosity of both the cement / SCM (fly ash and calcined clay) blend and 100% cement. Therefore, once calibration curves are generated, the rapid water absorption results described in this disclosure can be used to predict the yield stress and viscosity of cementitious mixtures containing unactivated or activated clay with different cement / SCM ratios, such as at least 50:50 or up to 50:50, at least 55:45 or up to 55:45, at least 60:40 or up to 60:40, at least 65:35 or up to 65:35, at least 70:30 or up to 70:30, at least 75:25 or up to 75:25, at least 80:20 or up to 80:20, at least 85:15 or up to 85:15, at least 90:10 or up to 90:10, and / or at least 95:5 or up to 95:5. Furthermore, once calibration curves are established, the rapid water absorption method can be used to measure the demand for water-reducing agents and / or superplasticizers in cement systems. The water absorption of superplasticizers (SCMs) reduces the effective water content in the system, and this absorption is even greater for particles with large surface areas and internal porosity. This reduction in water increases interparticle contact and forces, ultimately reducing the flow properties of the gelled mixture, such as yield stress and / or viscosity. Therefore, water-reducing agents or superplasticizers can be added to counteract the increased interparticle forces induced by SCMs. Superplasticizer requirements are typically determined by adjusting the dosage of water-reducing agents or superplasticizers to achieve a specific flow, a process that can be labor-intensive and requires multiple flow-related tests involving systematic dosage changes. The relationship between water absorption and the demand for water-reducing agents or superplasticizers can be used to quickly predict the water-reducing agent or superplasticizer requirements of SCMs. To this end, calibration curves can be established relating the demand for individual water-reducing agents or superplasticizers and their water absorption for different SCMs. These calibration curves can be used to quickly test the demand for water-reducing agents or superplasticizers for new SCMs. Water-reducing agents and superplasticizers are defined by ASTM C49. Chemically, they may be based on, but are not limited to, lignin sulfonic acid, modified lignin sulfonates, hydroxycarboxylic acids, hydroxylated polymers, sulfonated melamine, sulfonated naphthol condensates and / or polycarboxylic acid ester ethers.

[0055] The determination of ion concentration and water absorption for predicting the reactivity and rheological properties (e.g., yield stress and viscosity) of SCM-containing gel mixtures can be performed in parallel online. An exemplary online method is shown in Figure 1 In this embodiment, after calcination occurs, multiple samples (i.e., at least two samples), each containing calcined clay, can be obtained from the clay material being conveyed through the kiln. For example, Figure 1The conveyor belt 108 shown may include one or more additional openings (not visible) for collecting multiple samples. Samples can be obtained from adjacent areas of the clay material. As described above, one sample can be immersed in an alkaline or acidic aqueous solution. While the sample undergoes dissolution, the concentration of one or more ions in the alkaline or acidic aqueous solution is determined, as described above, to predict reactivity. Simultaneously with this analysis, another sample can be placed on a porous substrate in contact with a water source, and the aforementioned water absorption analysis can be performed to predict yield stress and / or viscosity. Based on the analysis, calcination conditions (e.g., calcination temperature, residence time) or activation conditions (e.g., grinding, blending, homogenization) can be adjusted online as needed.

[0056] More generally, methods for predicting the behavior of activated clay in a cementitious mixture may include obtaining one or more samples from the clay material after activation or calcination, each sample containing activated clay. The one or more samples may be obtained from adjacent regions of the clay material. Multiple batches of alkaline or acidic aqueous solutions containing portions of one or more samples (e.g., a first sample) may be analyzed as described above to determine aluminum and silicon ion concentrations as a function of time or at predetermined times. The water absorption of a second sample may also be determined as described above. This method may include predicting the reactivity of the activated clay in the cementitious mixture based on the determined concentrations of aluminum and silicon ions (e.g., using the predetermined factor described above applied to the aluminum ion concentration in μM and added to the Si concentration in μM; see [link to relevant documentation]). Figure 5 Alternatively, the method may include predicting the yield stress and / or viscosity of a cementitious mixture comprising activated clay based on water absorption measurements (e.g., see Figure 7). Finally, if the predicted reactivity and / or rheological properties (yield stress and / or viscosity) are not optimal, the calcination conditions or mechanochemical activation conditions in the kiln can be adjusted.

[0057] Example

[0058] The dissolution of various uncalcined and calcined clays in NaOH solution at 90℃ was monitored, and the dissolution behavior was compared with that obtained by 7-day R... 3 The reactivity measured by the isothermal calorimeter method is correlated.

[0059] Materials and methods

[0060] Material

[0061] Three pure clays were obtained from the Clay Minerals Society, including low-defect kaolinite from Warren County, Georgia, USA; Na-rich montmorillonite from Victoria, Australia; and an illite-montmorillonite mixture (70 / 30 ordered) from Slovakia. In addition, five calcined clays and seventeen uncalcined clays were obtained from various commercial companies and countries.

[0062] Calcination of clay

[0063] Clay was calcined in an alumina crucible using an MTI furnace. The temperature was increased to the desired temperature at a rate of 10°C / min and held for two hours before cooling to 150°C. The crucible was then transferred to a desiccator for further cooling to room temperature. High-grade kaolinite was calcined at 400–1000°C. A mixture of Na-montmorillonite and 70 / 30 illite / montmorillonite was calcined at 600–1000°C. Seventeen types of natural clay were calcined at 800°C, which is reportedly optimal for certain types of low-grade kaolinite clay.

[0064] ASTM C1897 R 3 test

[0065] Using ASTM C1897 R 3 The hardening reactivity of uncalcined and calcined clays was tested using isothermal calorimetry. Calcium hydroxide (Acros Organics, >98%), calcium carbonate (Acros Organics, >99%), potassium hydroxide (Fisher Scientific, ACS grade), and potassium sulfate (Fisher Scientific, ACS grade) were mixed with the clay at 1600 rpm for two minutes using a manual mixer. The heat of hydration was monitored for seven days at 40°C using an isothermal calorimeter (TAM Air, TA Instruments).

[0066] Dissolution test and spectrophotometric analysis

[0067] Clay dissolution in 4M NaOH solution was tracked at a solid-liquid ratio of 0.5 g / L. The temperature was maintained at 90 ± 0.5 °C using a water bath. Solution samples were collected over 1–15 minutes, filtered through a 0.22 μm PTFE filter, and acidified with HCl.

[0068] The Si concentration was determined using ASTM D859. Ammonium molybdate was added to a diluted sample solution acidified with HCl, followed by the addition of oxalic acid and amino-naphthol-sulfonic acid solution. The absorbance at 815 nm was measured using a Cary 5G spectrophotometer. A calibration curve was constructed using a silicon standard solution (Millipore) and used to determine the Si concentration in the sample solution.

[0069] Al concentration was determined using the 3500-Al B standard method. Sodium acetate buffer was used to achieve pH 6.0. Chrome cyanide R solution was added to form a pink complex with Al, and the Al concentration was determined using absorbance at 535 nm.

[0070] Camera measurement

[0071] A camera image analysis method was developed as a low-cost alternative for determining Al and Si. Instead of using a spectrophotometer to measure absorbance, an image of the colored solution is obtained using a camera. Code was developed to extract red (r), green (g), and blue (b) values ​​from the image. The b value was used to replace the absorbance at 815 nm to obtain a linear calibration curve and determine the Si concentration in the solution. The 3r + b value was used to replace the absorbance at 535 nm to determine the Al concentration. (Reference) Figure 4E During each image capture, a reference band with precisely known RGB values ​​is included next to the sample vial to serve as a standard for calibrating the camera's color response to each set of measurements. A camera (not shown) pointing left is located on the right side so that the liquid sample and the band are in the same image, and the band can be used for calibration. Upon image capture, the RGB values ​​of the reference band are extracted and compared to their known values ​​to calculate a correction matrix for each color channel. These factors are then applied to normalize the RGB values ​​obtained from the sample vial, ensuring that color measurements are consistent and reproducible under different lighting conditions and camera settings. By combining these calibration steps, the reliability and interlaboratory reproducibility of camera-based colorimetric analysis can be enhanced, making it a viable alternative to more traditional spectrophotometry.

[0072] Results and discussion

[0073] clay R 3 Cumulative heat release

[0074] R of high-grade kaolinite, Na-montmorillonite and 70 / 30 illite / montmorillonite mixed layers in 0-7 days 3 The evolution of cumulative heat release during the test is shown in Figures 8A-8C High-grade kaolinite reacts rapidly in R 3~80% of the reaction was completed on the first day of testing. The Na-montmorillonite reaction was slow, and most of the reaction gradually slowed down after three days. On the first day, the 800°C sample did not show a higher heat release than other samples, but it increased thereafter, indicating a delayed reaction in the dehydroxylated phase. The 70 / 30 illite / montmorillonite mixture calcined at 600-800°C showed a slow and continuously increasing cumulative heat, and the curve did not flatten even after seven days. This observation is consistent with previous studies finding that calcined illite is a slow-reacting material. The delayed reaction of the 70 / 30 illite / montmorillonite mixture was more pronounced: the sample calcined at 800°C released more heat than the 700°C sample only after two days. The heat release of the 70 / 30 illite / montmorillonite mixture calcined at 900°C was lower than that of the uncalcined sample in the first two days, and only became higher than other samples after five days. The delayed reaction of montmorillonite and illite may be related to their incomplete amorphization during calcination and fine-grain sintering, which could explain their low reactivity.

[0075] 7d R 3 Thermal drawing on Figure 8D High-grade kaolinite is activated within a wide temperature range of 500-900℃. At these temperatures, R... 3 The thermal conductivity is similar to ~1000 J / g SCM, reaching its maximum at 700℃. Optimal temperature range, maximum temperature, and R... 3 The calorific values ​​were consistent with previous reports on high-grade kaolinite. The over-calcined sample at 1000℃, the uncalcined high-grade kaolinite, and the sample calcined at 400℃ were non-reactive (<100 J / g SCM). Conversely, the uncalcined Na-montmorillonite exhibited some degree of hardening reactivity, with a 7d R0. 3 The heat of reactivity is 156 J / g SCM. After calcination at 600-800℃, the reactivity gradually increases, reaching 457 J / g SCM at 800℃. 3 It heats and becomes nonreactive at 900 and 1000 °C. The reactivity of montmorillonite, much lower than that of kaolinite, and its optimal calcination temperature of 800 °C are consistent with findings from previous studies. The uncalcined 70 / 30 illite / montmorillonite mixed layer has a 7d R0 of 84 J / g SCM. 3 The heat was gradually increased to 260 J / g SCM, while the calcination temperature increased to 900 °C. At 1000 °C, the 70 / 30 illite / montmorillonite mixture was over-calcined and became non-reactive. The low reactivity and optimal calcination conditions at 900 °C are consistent with recent observations of illite.

[0076] Clay dissolution

[0077] Besides R3 In addition to the tests, the dissolution behavior of a high-grade kaolinite, Na-montmorillonite, and 70 / 30 illite / montmorillonite mixed layer in 4M NaOH solution at 90°C was also monitored for 15 minutes using the method described in this disclosure. 3 During testing, the release of Al and Si from high-grade kaolinite showed a similar trend to that of thermal generation: samples calcined at 500-900℃ dissolved rapidly, and the concentrations of Al and Si plateaued after 5 minutes. Figure 9A and 9B The uncalcined samples and those calcined at 400℃ and 1000℃ dissolved much more slowly than other samples, and the concentrations of Al and Si increased steadily over 1-15 minutes, with 1000℃ > 400℃ > uncalcined. Regarding the Si / Al ratio, most samples from 500-900℃ showed uniform dissolution, with the Si / Al ratio approaching 1. Figure 9B The uncalcined sample maintained a Si / Al ratio below 0.5, indicating preferential Al dissolution. The 400°C sample showed preferential Al dissolution at 1 minute, gradually transitioning to preferential Si dissolution at 15 minutes. This difference suggests that while the calcination temperature of 400°C does not result in a hardening of the reactive material, some changes in mineral structure occur. The 1000°C sample dissolved uniformly within the first 2 minutes. The Si / Al ratio increased to 1.8 at 5 minutes and gradually decreased over 10–15 minutes. The increase in the Si / Al ratio is likely due to the dissolution of amorphous silica formed after the recrystallization of metakaolin. The subsequent decrease in the Si / Al ratio appears to indicate that Al remains slowly soluble under the conditions used, even after recrystallization at 1000°C. All these differences in dissolution behavior can help distinguish between materials that have been properly and improperly calcined.

[0078] Na-montmorillonite dissolves more slowly than high-grade kaolinite, which is consistent with their reactivity. Figure 10A and 10B The Al and Si concentrations of all samples were increased over 1–15 minutes, in the order of 800℃ > 700℃ > 600℃ > uncalcined > 900℃ ≈ 1000℃. The results were consistent with R. 3 Consistent. The Si / Al ratio of samples from 25-800℃ is close to 3, indicating consistent dissolution. Figure 10C Samples at 900 and 1000 °C showed that Al preferentially dissolved within the first 2 minutes, while Si preferentially dissolved after 5 minutes, indicating the dissolution of the inert phase formed during the over-calcination of montmorillonite.

[0079] The 70 / 30 illite / montmorillonite mixed layer dissolves more slowly than Na-montmorillonite. Figure 11A and 11BThis is consistent with its lower reactivity. At 1 and 2 minutes, the Al and Si concentrations released from the 800°C sample were lower than those released from 700°C, and became higher after 5 minutes. The Si concentration of the 900°C sample was lower than that of the uncalcined sample at 1 and 2 minutes, and became highest after 10 minutes. Their trends are consistent with R... 3 The delayed dehydroxylation phase observed during exothermic reactions is consistent with the evolution of Al and Si concentrations, indicating that the reaction is related to R. 3 The measured reactivity was highly consistent. The Si / Al ratio of the 70 / 30 illite / montmorillonite mixed layer showed consistent solubility in both uncalcined and properly calcined samples. Figure 11C The over-calcined samples showed an increasing Si / Al ratio over time, similar to over-calcined montmorillonite. Figure 10C ).

[0080] Ion concentration was measured using a camera.

[0081] The standard method described above uses colorimetric analysis with a spectrophotometer to determine the concentrations of Al and Si, rather than more expensive methods such as inductively coupled plasma optical emission spectroscopy (ICP-OES) or mass spectrometry (ICP-MS). To further reduce instrument costs, a colorimetric analysis method based on camera images has been developed. Figure 12A and 12B The results show that the Al and Si concentrations determined using this camera image analysis method are comparable to those obtained using a spectrophotometer. This indicates that color analysis based on camera imaging of colored solutions can be used as an alternative to absorbance at certain wavelengths for quantitative analysis.

[0082] Dissolution and R 3 Correlation between heat

[0083] To provide a more quantitative comparison between reactivity and solubility, Figures 13A-13D And 14A-14D showed 7d R 3 Correlation between Al and Si concentrations during heat and dissolution (1-15 minutes). For high-grade kaolinite, because the reactivity is ~1000 J / g SCM or less than 50 J / g SCM, R... 2 It was high before 5 minutes and decreased after 10 minutes due to the dissolution of the over-calcined sample. Figure 13A and 14A For Na-montmorillonite, the concentrations of Al and Si after 5 minutes were compared with those after 7 days. 3 The optimal heat matching is primarily due to the fact that the most reactive sample calcined at 800°C exhibits lower dissolved Al and Si concentrations within 1–2 minutes compared to the sample calcined at 700°C, consistent with the lower cumulative heat over 1 day. Figure 13B and14B For illite-based clays, optimal correlation was achieved using Al and Si concentrations dissolved at 15 minutes, due to the slow reaction of illite calcined at 900°C. Figure 13C and 14C If the composition of the target clay is known, it may be better to select a specific dissolution duration that best suits the target clay phase. For general analysis of different types of clay, a duration of 5 minutes was used in the following analyses in this study because illite has low and negligible reactivity compared to kaolinite and montmorillonite.

[0084] Figures 15A-15C The 7-day cumulative R values ​​for all three pure clays and five commercial metakaolinites C1-C5 are shown. 3 The correlation between the results and dissolution was established. Both Al and Si concentrations were matched with the 7-day cumulative heat, R. 2 The values ​​were 0.97 and 0.95, respectively. However, high R... 2 This is primarily because pure metakaolinite samples exhibit significantly higher reactivity than other samples. Closer examination of other samples revealed that Al concentration underestimated the reactivity of montmorillonite, while Si concentration overestimated it. This is because the Al:Si ratio in montmorillonite is approximately 1:3, contrasting with the approximately 1:1 ratio in kaolinite. Therefore, methods using reactive alumina or silica content may have limitations. For indices applicable to different types of clay, a combination of Al and Si concentrations is preferable. This study has demonstrated that using the total dissolved mass of alumina and silica yields a better correlation (R0). 2 =0.98) ( Figure 15C The problem with this method is that it does not account for the different contributions of Al and Si to the heat generation. Based on the enthalpy of dissolution of alumina and silica, a factor of 1.54 can be applied to the Al concentration in μM and added to the Si concentration in μM. Figure 16A This new solubility index gives a value similar to R. 2 =0.98 of clay's 7d R 3 The best correlation was found between the cumulative heat and the exponents. These results indicate that the R values ​​of these clays can be accurately predicted based on the indices of dissolved Al and Si. 3 Cumulative heat (reactivity).

[0085] To further investigate the applicability of the developed method to impure clays, five commercial samples and seventeen natural impure samples were tested, along with their solubility indices and R0 values. 3 The results are shown in Figure 16B Although linearly correlated R 2 It's still good up to 0.900, but some natural samples have higher R values ​​than their R values. 3The high concentrations of dissolved Al and Si indicate the dissolution of other phases in these samples.

[0086] To address this issue, a method was developed to mitigate the influence of dissolved impurities by subtracting the dissolved Al and Si from the uncalcined original sample. For industrial production, uncalcined samples are readily available. Taking advantage of this, it is assumed that the reactivity of the clay is provided by calcination, and that the dissolution of at least some impurities is unaffected by calcination. Therefore, subtracting the concentration of dissolved Al and Si from the uncalcined sample may eliminate the influence of these impurity phases. Figure 16C The UR that can be described as an adjustment is shown. 2 The results of deducting the solubility index. The bias of the natural sample is reduced, and the R-squared of the linear fit is improved. 2 It increased to approximately 0.92.

[0087] In addition to the aforementioned clays, UR has been developed 2 The applicability of the method to another type of SCM, namely fly ash, was also verified. Note that UR 2 The method refers to the "ultra-fast responsiveness" method. R 3 Alternatively, the "fast" method takes 7 days, so UR is used here. 2 Method. Thirty-seven types of fly ash (C and F categories) were dissolved in 50 mM KOH solution at 90 °C. The Al concentration dissolved after 15 minutes was multiplied by a factor of 0.4 and added to the Si concentration dissolved after 15 minutes to form a 15-minute UR. 2 Solubility index. Its relationship with 7d R 3 The correlation of the results is shown in Figure 17 And R 2 Up to 0.91. These results show that UR 2 The method can also accurately predict the R of fly ash. 3 Cumulative heat (reactivity).

[0088] This disclosure includes the following aspects:

[0089] The first aspect relates to a method for analyzing auxiliary cementitious materials (SCM), the method comprising: obtaining a sample containing SCM; immersing the sample in an alkaline or acidic aqueous solution, thereby causing the sample to dissolve; determining the ion concentration in the alkaline or acidic aqueous solution at a predetermined time after immersion of the sample; and predicting the reactivity of the SCM in the cementitious mixture based on the ion concentration.

[0090] The second aspect relates to the method of the first aspect, wherein the SCM is selected from unactivated clay, calcined clay, fly ash, silica fume, recycled ash, ground granular blast furnace slag, non-ferrous slag, steel slag, copper slag, natural volcanic ash, ash from agricultural waste, ash from waste-to-energy conversion, waste glass, bauxite residue, limestone, zeolite and / or filler materials.

[0091] The third aspect relates to any of the methods described above, wherein the concentration of one or more ions selected from aluminum, silicon, calcium, sodium, potassium, magnesium, iron, and sulfur is determined.

[0092] The fourth aspect relates to the methods of the foregoing aspects, wherein the ions are selected from aluminum and silicon.

[0093] The fifth aspect of the method relating to any of the foregoing aspects further includes: activating the clay material prior to obtaining the sample, said sample being obtained from the activated clay material.

[0094] The sixth aspect relates to the methods of the foregoing aspects, wherein the activation includes calcination, thermal activation, mechanical activation and / or mechanochemical activation.

[0095] The seventh aspect relates to any of the methods described above, wherein clay material is conveyed through a kiln for activation.

[0096] The eighth aspect relates to the method of the foregoing aspects, wherein after the clay material leaves the heating zone of the kiln, the sample falls by gravity through an opening in the conveyor belt into a collection container.

[0097] The ninth aspect relates to the method according to any of the foregoing aspects, wherein the sample is obtained after co-grinding or mixing with one or more other materials.

[0098] The tenth aspect relates to any of the foregoing methods, and further includes obtaining multiple samples for analysis; or further includes separating the samples into multiple samples for analysis.

[0099] The eleventh aspect relates to any of the methods described above, wherein the amount of sample obtained is less than 500 g, less than 200 g, less than 100 g, less than 50 g, less than 20 g, less than 10 g, less than 5 g, less than 2 g, less than 1 g and / or as low as 0.1 g, as low as 0.01 g or as low as 0.001 g.

[0100] The twelfth aspect relates to any of the methods described in the foregoing aspects, wherein the sample is immersed in an alkaline or acidic aqueous solution at a temperature ranging from 25°C to 100°C and / or from 60°C to 95°C.

[0101] The thirteenth aspect relates to any of the methods described in the foregoing aspects, wherein the concentration of the sample in the alkaline or acidic aqueous solution is at least 1 ng / L and up to 1 kg / L.

[0102] The fourteenth aspect relates to any of the methods described above, wherein the predetermined time is 60 minutes or less, 30 minutes or less, 15 minutes or less, 5 minutes or less and / or at least 2 minutes or at least 1 minute.

[0103] The fifteenth aspect relates to the method according to any of the preceding aspects, wherein the acidic aqueous solution comprises an acid selected from hydrochloric acid, nitric acid and sulfuric acid, and / or wherein the alkaline aqueous solution comprises a base selected from sodium hydroxide, potassium hydroxide and lithium hydroxide.

[0104] The sixteenth aspect relates to any of the foregoing methods, further comprising: obtaining a plurality of said samples; and preparing multiple batches of alkaline or acidic aqueous solutions, each batch containing one sample.

[0105] The seventeenth aspect relates to the methods of the foregoing aspects, wherein each batch of alkaline or acidic aqueous solution is used to determine the ion concentration of different ions.

[0106] The eighteenth aspect relates to any of the foregoing methods, further comprising: separating and / or diluting the alkaline or acidic aqueous solution containing the sample to form multiple batches of the alkaline or acidic aqueous solution.

[0107] The nineteenth aspect relates to any of the methods described above, wherein each batch of alkaline or acidic aqueous solution is used to determine the ion concentration of different ions.

[0108] The twentieth aspect relates to the method according to any of the foregoing aspects, wherein determining the concentration of the ion includes performing colorimetric analysis, atomic adsorption spectroscopy, photoemission spectroscopy, mass spectrometry, titration, selective ion electrode, precipitation, chromatography, fluorescence spectroscopy, and / or electrophoresis.

[0109] The twenty-first aspect relates to the method according to any of the foregoing aspects, wherein determining the ion concentration includes performing colorimetric analysis, and further includes adding one or more chemicals to the alkaline or acidic aqueous solution, the chemicals being configured to cause a color change in the presence of a specific ion.

[0110] The twenty-second aspect relates to the methods of the foregoing aspects, wherein one or more chemicals are selected from molybdates, chrome blue R, chrome azurite S, fluorescent gallium reagent, 8-hydroxyquinoline, salicylaldehyde pyridine carboxyhydrazone, morin, catechol violet, quercetin, test iron, aluminum reagent, and o-cresolphthalein complex ketone.

[0111] The twenty-third aspect relates to any of the methods described above, and further includes adding a pH buffer, a reducing agent, and / or a masking agent to the alkaline or acidic aqueous solution.

[0112] The twenty-fourth aspect relates to the method according to any of the foregoing aspects, wherein the one or more chemicals comprise a first group of chemicals and a second group of chemicals, wherein the first group of chemicals is configured to cause a color change in the presence of silicon ions and is added to a first batch of the alkaline or acidic aqueous solution, and wherein the second group of chemicals is configured to cause a color change in the presence of aluminum ions and is added to a second batch of the alkaline or acidic aqueous solution.

[0113] The twenty-fifth aspect relates to the methods of the foregoing aspects, wherein the first group of chemicals is selected in accordance with ASTM D859.

[0114] The twenty-sixth aspect relates to any of the methods described in the foregoing aspects, wherein a second group of chemicals is selected based on 3500-Al B.

[0115] The twenty-seventh aspect relates to the method according to any of the foregoing aspects, wherein performing colorimetric analysis includes using ultraviolet-visible spectroscopy, camera image analysis, or visual comparison.

[0116] The twenty-eighth aspect relates to the method of the foregoing aspect, wherein the use of ultraviolet-visible spectroscopy includes: irradiating the sample with ultraviolet and / or visible light; measuring absorbance at a predetermined wavelength; and determining the ion concentration based on the absorbance.

[0117] The twenty-ninth aspect relates to the method according to any of the foregoing aspects, wherein the camera image analysis includes: obtaining a photographic image of the sample; converting the photographic image into an RGB format including red, green, and blue channels; measuring the average luminance intensity values ​​of the red, green, and blue channels; normalizing the average luminance intensity values ​​to a range of 0 to 1; and determining the ion concentration based on the normalized luminance intensity values.

[0118] The thirtieth aspect relates to any of the methods described above, wherein predicting the reactivity of the SCM comprises: multiplying an aluminum ion concentration in μM by a predetermined factor to obtain a product; adding the product to a silicon ion concentration in μM; and determining R. 2 R value is at least 0.98 3 Cumulative heat.

[0119] The thirty-first aspect relates to the method according to any of the foregoing aspects, wherein the predetermined factor is in the range of about 1.1 to 1.7.

[0120] The thirty-second aspect relates to any of the methods in the foregoing aspects, and also includes adjusting the activation conditions of the clay if the predicted reactivity of the SCM is not optimal.

[0121] The thirty-third aspect relates to the aforementioned aspects, wherein adjusting the activation conditions includes adjusting the grinding time of the clay material.

[0122] The thirty-fourth aspect relates to any of the methods in the foregoing aspects, wherein adjusting the activation conditions includes adjusting the calcination temperature and / or residence time of the clay material.

[0123] The thirty-fifth aspect relates to the method according to any of the foregoing aspects, further comprising: obtaining a plurality of samples of the SCM, the plurality of samples including a first sample and a second sample, the first sample being immersed in the alkaline or acidic aqueous solution for determining ion concentration; and determining the water absorbency of the second sample, the water absorbency indicating the processability of the SCM.

[0124] The thirty-sixth aspect relates to the method according to any of the foregoing aspects, wherein determining the water absorbency of the second sample comprises: placing the second sample on a material in contact with a water source; and measuring the change in water level of the water source as the second sample absorbs water through the porous material.

[0125] The thirty-seventh aspect relates to a method for analyzing SCM, the method comprising: obtaining a sample containing SCM; placing the sample on a porous substrate in contact with a water source; measuring the water level change of the water source as the sample absorbs water through the porous substrate; and determining the water absorbency of the sample, the water absorbency predicting the rheological properties (yield stress and / or viscosity) of the gel mixture containing SCM.

[0126] The thirty-eighth aspect relates to the method according to any of the foregoing aspects, further comprising: predicting the yield stress and / or viscosity of the gel mixture comprising the SCM based on the water absorption.

[0127] The thirty-ninth aspect relates to the method according to any of the foregoing aspects, and further includes quantifying the amount of (one or more) water-reducing agents and / or (one or more) superplasticizers to be added to the gelling mixture based on water absorption.

[0128] The fortieth aspect relates to any of the methods described above, and also includes adjusting the activation conditions of the clay material if the predicted yield stress and / or viscosity are not optimal.

[0129] The forty-first aspect relates to any of the foregoing methods, the method further comprising using a dropper to maintain a water supply, the dropper comprising a U-shaped curve and positioned in a horizontal configuration at a height equal to the height of the porous substrate.

[0130] The forty-second aspect relates to any of the methods described above, wherein the water absorption is determined within 10 minutes or 2 minutes of positioning the sample on the porous substrate.

[0131] The forty-third aspect relates to any of the methods in the foregoing aspects, wherein the amount of sample obtained is less than 5 g, 2 g, less than 1 g and / or as low as 0.1 g or as low as 0.01 g.

[0132] The forty-fourth aspect relates to any of the methods in the foregoing aspects, wherein the SCM is selected from unactivated clay, activated clay, calcined clay, fly ash, silica fume, recycled ash, ground granular blast furnace slag, natural volcanic ash, ash from agricultural waste, zeolite and / or filler materials.

[0133] The forty-fifth aspect relates to any of the foregoing aspects of the method, a method for predicting the behavior of clay in a cementitious mixture, the method comprising: after activation, obtaining one or more samples from clay material, each sample containing activated clay, the one or more samples comprising or being divided into first and second samples; at a predetermined time, determining the concentrations of silicon ions and aluminum ions in corresponding first and second batches of alkaline or acidic aqueous solutions containing the first sample; determining the water absorption of the second sample; predicting the reactivity of the activated clay in the cementitious mixture based on the concentrations of silicon and aluminum ions; predicting the rheological properties (yield stress and viscosity) of the cementitious mixture including the activated clay based on the water absorption; and adjusting the activation conditions of the clay if the predicted reactivity and / or yield stress are not optimal.

[0134] Although the invention has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible without departing from the invention. Therefore, the spirit and scope of the appended claims should not be limited to the preferred embodiments described herein. All embodiments within the meaning of the claims, whether literal or equivalent, are considered to be included herein.

[0135] Furthermore, the advantages described above are not necessarily the only advantages of the present invention, and it is not necessarily expected that all of the described advantages will be achieved through each embodiment of the present invention.

Claims

1. A method for analyzing auxiliary cementitious materials (SCM), the method comprising: Obtain a sample containing SCM; The sample is immersed in an alkaline or acidic aqueous solution, thereby causing the sample to dissolve. The ion concentration in the aqueous solution was determined at a predetermined time after immersion of the sample; and Predicting the reactivity of SCM in gelling mixtures based on ion concentration.

2. The method according to claim 1, wherein the SCM is selected from unactivated clay, calcined clay, fly ash, silica fume, recycled ash, ground granular blast furnace slag, non-ferrous slag, steel slag, copper slag, natural volcanic ash, ash from agricultural waste, ash from waste-to-energy conversion, waste glass, bauxite residue, limestone, zeolite and / or filler materials.

3. The method of claim 1, wherein the concentration of one or more ions selected from aluminum, silicon, calcium, sodium, potassium, magnesium, iron and sulfur is determined.

4. The method of claim 3, wherein the ions are selected from aluminum and silicon.

5. The method according to claim 1, further comprising: Before obtaining the sample, the clay material is activated, and the sample is obtained from the activated clay material.

6. The method of claim 5, wherein the activation comprises calcination, thermal activation, mechanical activation, and / or mechanochemical activation.

7. The method of claim 5, wherein the clay material is conveyed through a kiln for activation.

8. The method of claim 7, wherein after the clay material leaves the heating zone of the kiln, the sample falls by gravity through an opening in the conveyor belt into a collection container.

9. The method of claim 1, wherein the sample is obtained after co-grinding or mixing with one or more other materials.

10. The method of claim 1, further comprising obtaining a plurality of samples for analysis; or Further, it includes separating the sample into multiple samples for analysis.

11. The method of claim 1, wherein the amount of sample obtained is less than 500 grams and / or as low as 0.001 grams.

12. The method of claim 1, wherein the sample is immersed in an alkaline or acidic aqueous solution at a temperature ranging from 25°C to 100°C.

13. The method of claim 1, wherein the concentration of the sample in the alkaline or acidic aqueous solution is at least 1 ng / L and up to 1 kg / L.

14. The method of claim 1, wherein the predetermined time is 60 minutes or less.

15. The method of claim 1, wherein the acidic aqueous solution comprises an acid selected from hydrochloric acid, nitric acid, and sulfuric acid, and / or The alkaline aqueous solution contains an alkali selected from sodium hydroxide, potassium hydroxide, and lithium hydroxide.

16. The method of claim 1, further comprising: Multiple samples were obtained; and Prepare multiple batches of alkaline or acidic aqueous solutions, each batch containing one sample.

17. The method of claim 16, wherein each batch of alkaline or acidic aqueous solution is used to determine the ion concentration of different ions.

18. The method of claim 1, further comprising: Separate and / or dilute the alkaline or acidic aqueous solution containing the sample to form multiple batches of the alkaline or acidic aqueous solution.

19. The method of claim 18, wherein each batch of alkaline or acidic aqueous solution is used to determine the ion concentration of different ions.

20. The method of claim 1, wherein determining the ion concentration comprises performing colorimetric analysis, atomic adsorption spectroscopy, photoemission spectroscopy, mass spectrometry, titration, selective ion electrode, precipitation, chromatography, fluorescence spectroscopy, and / or electrophoresis.

21. The method of claim 1, wherein determining the ion concentration includes performing colorimetric analysis, and further includes: One or more chemicals are added to the alkaline or acidic aqueous solution, the chemicals being configured to cause a color change in the presence of specific ions.

22. The method of claim 21, wherein the one or more chemicals are selected from molybdate, chrome blue R, chrome azurite S, fluorescent gallium reagent, 8-hydroxyquinoline, salicylaldehyde pyridine carboxyhydrazone, morin, catechol violet, quercetin, ferrite, aluminum reagent, and o-cresolphthalein complex ketone.

23. The method of claim 21 further comprises adding a pH buffer, a reducing agent, and / or a masking agent to the alkaline or acidic aqueous solution.

24. The method of claim 21, wherein the one or more chemicals comprise a first group of chemicals and a second group of chemicals. The first group of chemicals is formulated to cause a color change based on the presence of silicon ions and added to the first batch of alkaline or acidic aqueous solutions. The second group of chemicals is formulated to cause a color change in the presence of aluminum ions and added to the second batch of the alkaline or acidic aqueous solution.

25. The method of claim 24, wherein the first group of chemicals is selected according to ASTM D859.

26. The method of claim 24, wherein the second group of chemicals is selected according to 3500-Al B.

27. The method of claim 21, wherein performing colorimetric analysis includes using ultraviolet-visible spectroscopy, camera image analysis, or visual comparison.

28. The method of claim 27, wherein utilizing ultraviolet-visible spectroscopy comprises: The sample was irradiated with ultraviolet and / or visible light; Measure absorbance at a predetermined wavelength; The ion concentration is determined based on the absorbance.

29. The method of claim 27, wherein the analysis using camera images comprises: Obtain photographic images of the sample; The photographic image is converted into RGB format, which includes red, green, and blue channels; Measure the average luminance intensity values ​​of the red, green, and blue channels; The average luminance intensity value is normalized to the range of 0 to 1; and Ion concentration was determined based on normalized luminance intensity values.

30. The method of claim 1, wherein predicting the reactivity of the SCM comprises: The aluminum ion concentration in μM is multiplied by a predetermined factor to obtain the product; Add the silicon ion concentration in μM to the product; as well as Determine R 2 R value is at least 0.98 3 Cumulative heat.

31. The method of claim 30, wherein the predetermined factor is in the range of about 1.1 to 1.

7.

32. The method of claim 30 further includes adjusting the activation conditions of the clay material if the predicted reactivity of the SCM is not optimal.

33. The method of claim 32, wherein adjusting the activation conditions includes adjusting the grinding time of the clay material.

34. The method of claim 32, wherein adjusting the activation conditions includes adjusting the calcination temperature and / or residence time of the clay material.

35. The method of claim 1, further comprising: Multiple samples of the SCM are obtained, including a first sample and a second sample, wherein the first sample is immersed in the alkaline or acidic aqueous solution for determining the ion concentration; and The water absorption of the second sample was measured, which indicates the processability of the SCM.

36. The method of claim 35, wherein determining the water absorbency of the second sample comprises: The second sample was placed on a material that came into contact with the water source; and The water level change of the water source is measured when the second sample absorbs water passing through the porous material.

37. A method for analyzing SCM, the method comprising: Obtain a sample containing SCM; The sample was placed on a porous substrate that was in contact with a water source. The water level change of the water source was measured when the sample absorbed water passing through the porous substrate; and The water absorption of the sample was measured.

38. The method of claim 37, further comprising: The yield stress and / or viscosity of the gel mixture, including the SCM, are predicted based on the water absorption.

39. The method of claim 37, further comprising: The amount of (one or more) water-reducing agents and / or (one or more) superplasticizers to be added to the gelling mixture including SCM is quantified based on water absorption.

40. The method of claim 38 further includes adjusting the activation conditions of the clay material if the predicted yield stress and / or viscosity are not optimal.

41. The method of claim 37, further comprising using a dropper to maintain a water supply, the dropper comprising a U-shaped curve and positioned in a horizontal configuration at a height equal to the height of the porous substrate.

42. The method of claim 37, wherein the water absorption is determined within 10 minutes of positioning the sample on the porous substrate.

43. The method of claim 37, wherein the amount of sample obtained is less than 5 grams and / or as low as 0.01 grams.

44. The method of claim 37, wherein the SCM is selected from unactivated clay, activated clay, calcined clay, fly ash, silica fume, recycled ash, ground granular blast furnace slag, natural volcanic ash, ash from agricultural waste, zeolite, and filler materials.

45. A method for predicting the behavior of clay in a cementitious mixture, the method comprising: After activation, one or more samples are obtained from the clay material, each sample containing activated clay, the one or more samples comprising or being divided into first and second samples; At a predetermined time, the silicon ion concentration and aluminum ion concentration of the corresponding first and second batches of alkaline or acidic aqueous solutions containing the first sample are determined. The water absorption of the second sample was determined; Predicting the reactivity of activated clay in cementitious mixtures based on the concentration of silicon and aluminum ions. Based on water absorption, the prediction includes yield stress and viscosity; and If the predicted reactivity, yield stress, and / or viscosity are not optimal, adjust the activation conditions of the clay.

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