Backscattered Electron Image Analysis Research Articles

Nephrite from Xinjiang Qiemo Margou Deposit: Gemological and Geochemical Insights

The nephrite belt in the Altun Mountain–Western Kunlun Mountain region, which extends about 1300 km in Xinjiang, NW China, is the largest nephrite deposit in the world. The Qiemo region in the Altun Mountains is a crucial nephrite-producing area in China, with demonstrated substantial prospects for future exploration. While existing research has extensively investigated secondary nephrite deposits in the Karakash River and native black nephrite deposits in Guangxi Dahua, a comprehensive investigation of black nephrite from original deposits in Xinjiang is lacking. Margou black-toned nephrite was recently found in primary deposits in Qiemo County, Xinjiang; this makes in-depth research on the characteristics of this mine necessary. A number of technical analytical methods such as polarizing microscopy, Ultra-Deep Three-Dimensional Microscope, electron microprobe, back-scattered electron image analysis, X-ray fluorescence, and inductively coupled plasma mass spectrometry were employed for this research. An experimental test was conducted to elucidate the chemical and mineralogical composition, further clarifying the genetic types of the black and black cyan nephrite from the Margou deposit in Qiemo, Xinjiang. The results reveal that the nephrite is mainly composed of tremolite–actinolite, characterized by Mg/(Mg + Fe2+) ratios ranging from 0.86 to 1.0. Minor minerals include diopside, epidote, pargasite, apatite, zircon, pyrite, and magnetite. Bulk-rock rare earth element (REE) patterns exhibit distinctive features, such as negative Eu anomalies (δEu = 0.00–0.17), decreasing light REEs, a relatively flat distribution of heavy REEs, and low total REE concentrations (1.6–38.9 μg/g); furthermore, the Cr (6–21 μg/g) and Ni (2.5–4.5 μg/g) contents are remarkably low. The magmatic influence of granite appears to be a fundamental factor in the genesis of the magnesian skarn hosting Margou nephrite. The distinctive black and black cyan colors are attributed to heightened iron content, mainly associated with FeO (0.08~6.29 wt.%). Analyses of the chemical composition allow Margou nephrite to be classified as typical of magnesian skarn deposits.

Impact of Twin's Landscape on the Magnetic Damping of La2/3Sr1/3MnO3 Thin Films

AbstractUnderstanding the origin and mechanisms of magnetic damping in complex oxide materials is crucial for optimizing spin dynamics and tailoring their properties for specific spintronic applications. Ferromagnetic resonance spectroscopy (FMR) technique has been used to investigate the magnetic damping of multiple La2/3Sr1/3MnO3 (LSMO) epitaxial thin films with similar thickness and identical DC magnetic properties. However, the dynamic magnetic properties exhibit noticeable variations among samples. Microstructural analyses using X‐ray diffraction (XRD) and atomic force microscopy (AFM), confirm that the samples are structurally identical, except for minute differences in the miscut angles of the substrates. Nevertheless, when examining the samples using backscattered electron (BSE) images in scanning electron microscopy (SEM), significant disparities in the twin distribution are observed. These variations in the twin distribution directly correlate with the observed differences in the damping values. A careful image analysis of BSE images allows to demonstrate that the increase of damping is due to the pinning of the magnetization in the twin boundaries.

Effect of low-calcium and high-magnesium ferronickel slag on the microstructure and micromechanical properties of alkali-activated blended ground granulated blast furnace slag

In recent years, low-calcium and high-magnesium ferronickel slag (FNS) has been gradually used in the preparation of alkali-activated cements (AACs). An in-depth exploration of the microstructural characteristics is crucial for a thorough understanding and enhancement of the macroscopic behaviors of AACs. In this study, the microstructural composition and micromechanical properties of the alkali-activated ground granulated blast furnace slag (GGBS)-FNS cements (AASF) prepared with sodium silicate and sodium hydroxide as alkali activators were quantitatively studied. Backscattered electron image analysis (BSE-IA) and nanoindentation were selected to reveal the micromechanical properties of different phases in FNS particles and AASF pastes. The results show that the elastic modulus of sodium aluminosilicate hydrate (N-A-S-H) in alkali-activated FNS cement is about 17 GPa, which is similar to that of the gel phase in alkali-activated fly ash cement (AAFA) and alkali-activated metakaolin cement (AAMK), confirming that the micromechanical property of N-A-S-H gel is independent of the kind of precursor materials. The Ca/Si and Al/Si of the hydration products in AASF gradually decline as FNS is incorporated, whereas the Mg/Al steadily rises, increasing the elastic modulus of the inner hydration product (IP) phase in AASF. The reaction degree of GGBS is higher in the sodium silicate-activated AASF system, while more N-A-S-H gels are formed in the sodium hydroxide-activated AASF system. The incorporation of FNS is conducive to improving the reaction degree of GGBS, resulting in the increase of calcium silicoaluminate hydrate (C-A-S-H) content and a significant decrease in IP content in AASF.

Early-age shrinkage behavior of cement-fly ash paste under wind speeds: A study using BSE-IA and MIP techniques

While laboratory studies have shown that fly ash (FA) can reduce shrinkage in cement-based materials in the absence of wind, its impact on cement-based materials under wind speed conditions has not been extensively studied. This research investigates the influence of FA on the early-age shrinkage of cement paste under various wind speeds. The corresponding changes in pore structure were tested using mercury intrusion porosimetry (MIP) and backscattered electron image analysis (BSE-IA). The results show that under wind speed conditions, FA is not effective in reducing early-age shrinkage of cement paste. In fact, high levels of FA content can increase shrinkage values under wind speed conditions. Both wind speed and FA increase water evaporation, but they have different impact times. Although both wind speed and FA decrease mesopore content below 50 nm and increase water evaporation, they have opposite effects on early-age shrinkage. This suggests that mesopore content and water evaporation alone cannot fully characterize the change trend of early drying shrinkage. The two-factor parameter rs, which combines water evaporation and MIP-based pore size distribution, can effectively characterize drying shrinkage trends under the combined effects of wind speed and FA. BSE-IA can intuitively characterize pore size distribution above 200 nm, while the results of MIP underestimate the distribution of large capillary pores. Therefore, the current rs obtained based on MIP may be smaller than the actual value. With the advancement of testing technology in the future, rs can be further optimized.

Cementitious phase quantification using deep learning

This study investigates deep learning-based backscattered electron (BSE) image segmentation as a novel approach to automatise phase quantification of cementitious materials and estimate their degree of hydration and porosity. The case study was on Portland cement paste that hydrated from 1 day to 2 years. The initial findings suggest that using arbitrary thresholds for phase segmentation, a strong correlation can be established between the results from BSE image analysis, quantitative XRD, and EDS/BSE, particularly for samples with a hydration age >28 days. The second part demonstrates the success of automated image segmentation that relies on learning the material composition from a meticulously analysed image database, which can then predict the content of numerous other images within seconds. This novel approach can turn the analysis of cementitious materials' phase composition from a tedious process that requires specialised equipment and expertise into a routine test for quality control.

Influence of recycled concrete aggregate enhancement methods on the change of microstructure of ITZs in recycled aggregate concrete

Recycled concrete aggregate (RCA) enhancement is an important method to improve the performance of recycled aggregate concrete (RAC). However, the quantitative studies on the change of microstructure of interfacial transition zones (ITZs) were few and far, especially after enhancement of RCA with different methods. This paper investigated the influence of carbonation enhancement (carbonation time, soaking in CH saturated solution and then carbonation) and chemical enhancement (respectively soaking in Na2SiO3 saturated solution and cement-silica fume (CEM-SF) slurries) of RCA on the change of microstructure of ITZs (including the ITZ between old aggregate-new paste (ITZ1) and ITZ between old paste-new paste (ITZ2)) in RAC. The porosity, the un-hydrated cement particles (UH) content, the volume fraction of hydration products (VFHP) in ITZs and the width of ITZs were obtained by backscattered electron imaging analysis (BSE-IA) and energy dispersive spectrometer (EDS) analysis. Results showed that the carbonation enhancement of RCA could not effectively strengthen ITZ1. However, soaking RCA in Na2SiO3 saturated solution and CEM-SF slurries could decrease the porosity and the UH content, develop the VFHP, and reduce the width of ITZ1, then strengthening ITZ1. Both carbonation and chemical enhancement could take obviously improvement on ITZ2. Additional calcium sources could be added to RCA by soaking in CH saturated solution, improving the effect of carbonation enhancement of RCA. Soaking in CEM-SF slurries had a better improvement effect on ITZs. After RCA was soaked in CEM-SF slurries, the porosity in ITZ1 and ITZ2 decreased by 36.8% and 44.0%, the UH content of ITZ1 and ITZ2 decreased by 22.6% and 53.6%, the VFHP of ITZ1 and ITZ2 increased by 22.6% and 20.9%, and the width of ITZ1 and ITZ2 decreased by 42.9% and 50%. EDS analysis showed that the Ca/Si atomic ratio of ITZs was reduced after RCA enhancement, which generated more hydration products and then decreased the porosity and the width of ITZs.

Effects of Infantile Hypophosphatasia on Human Dental Tissue

Hypophosphatasia (HPP) is an inherited, systemic disorder, caused by loss-of-function variants of the ALPL gene encoding the enzyme tissue non-specific alkaline phosphatase (TNSALP). HPP is characterized by low serum TNSALP concentrations associated with defective bone mineralization and increased fracture risk. Dental manifestations have been reported as the exclusive feature (odontohypophosphatasia) and in combination with skeletal complications. Enzyme replacement therapy (asfotase alfa) has been shown to improve respiratory insufficiency and skeletal complications in HPP patients, while its effects on dental status have been understudied to date. In this study, quantitative backscattered electron imaging (qBEI) and histological analysis were performed on teeth from two patients with infantile HPP before and during asfotase alfa treatment and compared to matched healthy control teeth. qBEI and histological methods revealed varying mineralization patterns in cementum and dentin with lower mineralization in HPP. Furthermore, a significantly higher repair cementum thickness was observed in HPP compared to control teeth. Comparison before and during treatment showed minor improvements in mineralization and histological parameters in the patient when normalized to matched control teeth. HPP induces heterogeneous effects on mineralization and morphology of the dental status. Short treatment with asfotase alfa slightly affects mineralization in cementum and dentin. Despite HPP being a rare disease, its mild form occurs at higher prevalence. This study is of high clinical relevance as it expands our knowledge of HPP and dental involvement. Furthermore, it contributes to the understanding of dental tissue treatment, which has hardly been studied so far.

Measuring the hydration product proportion in composite cement paste by using quantitative BSE-EDS image analysis: A comparative study

Composite cement has attracted increasing interest in the construction material field from the view of environmental and economic benefits. However, the measurement of hydration product proportion in the composite cementitious system remains challenging due to the heterogeneity of components and the existence of amorphous phases. In this study, three grey value histogram-based Backscattered Electron (BSE) image analysis approaches were compared mutually at first. Then, two color clustering-based Energy Dispersive X-ray Spectroscopy (EDS) image analysis approaches are comparatively developed for intuitively quantifying the hydration product proportion. In the BSE image analysis, results indicate that Overflow Method and Gaussian Mixture Model (GMM) show more reliable and accurate results than Frequency Histogram Method. In the EDS image analysis, GMM is better than K-means in terms of accuracy and reproducibility, and the cluster number of three sufficiently meets the requirement of grain extraction. Finally, the BSE-EDS image analysis, which integrates the merits of above approaches was proposed, achieving the best measurement performance. The hydration product proportions determined by BSE, EDS, and BSE-EDS image analysis approaches in the current research are 73.5%, 74.7%, and 68.1%, respectively. The proposed BSE-EDS image analysis offers a way to identify the hydration products practically, reliably, and visually in the cementitious system.

Investigating the effect of polycarboxylate-ether based superplasticizer on the microstructure of cement paste during the setting process

There is limited measure available to quantify the effect of polycarboxylate-ether based superplasticizer (PCE) on the microstructure of cement-based systems during the first 24 h. To fill this gap, the backscattered electron image analysis (BSE-IA) alongside the ternary technique is used in this study to separate composed phases quantitively and then calculate the average spacing between cement particles. Besides, together with an examination of hydration heat, the skeleton development of reaction products is investigated. The results show that cement hydration is not a constant process, and the developing mode for hydration products region varies with the particle size of cement. In this regard, numerous hydration products may gather around small cement particles and then adsorb other unhydrated particles, forming the continuous region. By contrast, the particles possessing relatively large size are surrounded by noticeable pores, which interrupt the continuity of the hydration products region. When introducing PCE, the agglomeration of cement particles and the average spacing between cement particles reduced, manifesting as an enlarged hydration products region alongside a decreased porosity at the area surrounding large particles. However, this leads to a decreased hydration degree for cement and extends the setting time of cement paste.

Hydration characteristics and microstructure evolution of concrete with blended binders from LCD and OLED wastes

The use of pozzolanic waste materials as partial cement replacement is customary in contemporary concretes from the sustainability perspective. In this study, glass wastes from organic light-emitting diode (OLED) and liquid crystal display (LCD) were used waste as supplementary cementing material (SCM) in concrete. For the first time, detailed microstructural and hydration attributes have been studied for such blended concretes. Concretes with 10%, 20%, and 30% substitution of ordinary Portland cement (OPC) by OLED and LCD glass powders were developed. The resulting mechanical properties, hydration attributes, and microstructural features were studied at various ages, up to one year. Superior mechanical properties were shown after 28-day age for blended concretes; however, much profound improvement in compressive and flexural strength was observed at 1-year age. The enhanced mechanical properties of modified concretes are attributed to greater pozzolanic activity and secondary hydrates formation of OLED and LCD glass powders in alkaline cementitious matrix. Greater C-S-H gel formation, lower permeability, and more refined microstructure of the blended concrete were corroborated by thermogravimetric analysis (TGA), Rietveld quantitative phase analysis (RQPA), backscattered electron image analysis (BSE), and mercury intrusion porosimetry (MIP). 20 wt% has been found as the optimal value of cement replacement by either LCD or OLED powder. The results clearly indicate LCD and OLED can be successfully used as SCM for developing concrete with improved properties.

Ore mineralogy of podiform-type chromite deposit in Tedubara area and its vicinity, Kabaena Island, Indonesia

Kabaena Island is one of the areas in Southeast Sulawesi that has the potential for chromite deposits. This paper is aimed to provide information on the mineralogical aspects of chromitite from the research area. Back-scattered electron (BSE) imaging and chemical analysis of chromite were performed using an electron microprobe. Chromite deposits in the study area are of podiform-type. Chromite is massive and brecciated. Based on the content of Cr # = Cr/(Cr + Fe3+) of the chromite, comprised between 0.61 and 0.74, the studied chromitite can be classified as Cr-rich. The only PGM (Platinum Group Minerals) found in several chromitite samples is laurite (RuS2). PGM occurs enclosed in chromite crystals and in the contact with microfractures of chromite crystals.

Influence of interfacial microstructure on pullout behavior and failure mechanism of steel fibers embedded in cement-based materials

In this study, the failure mechanism of the fiber–matrix interface during pullout and the effective improvement of the pullout resistance were investigated. The interfacial bond properties of fibers from cement-based materials were systematically analyzed and compared using various modification methods, and the corresponding fiber–matrix interfacial microstructure was examined through quantitative characterization. Fiber pullout tests were performed to determine the bond properties, and backscattered electron (BSE) image analysis and microhardness tests were conducted for quantitative microstructure characterization. The surface morphology of the fibers after pulling out was assessed by scanning electron microscopy. The results showed that the different modification methods had different improvement effects on different microzones and pullout curve sections. The failure surface moved and tended to the weakest zone in the fiber–matrix interfacial microstructure. The modification methods should be applied carefully to ensure that the improvements to different microzones match, instead of simply increasing the degree of a modification method. A functional relationship between the porosity determined using BSE image analysis (BSE-IA) and the interfacial bond properties was established to correlate the fiber–matrix interfacial microstructure and fiber pullout behavior.

Combination usage of nano-SiO2-coated steel fiber and silica fume and its improvement effect on SFRCC

To further improve the fiber-matrix interfacial properties and enhance the macro-mechanical performances of steel fiber reinforced cement-based composite (SFRCC), two effective modification methods, nano-SiO2-coated steel fiber (NSF) targeted at the fiber-matrix interface and silica fume targeted at cement matrix, were tried to use together. The modification effects of NSF, silica fume and their combination usage were characterized and analyzed at multi-levels. Backscattered electron image analysis (BSE-IA) was used for micro microstructure characterization and the micro-hardness test was employed to evaluate the micro-mechanical property. A fiber pull-out test was drawn up and the interfacial bond properties, including the pull-out load-displacement curve, average bond strength and pull-out energy, were obtained. Flexural and compressive tests were conducted and the bending performance, flexural and compressive strength were focused on. The results show that the modification mechanisms of NSF and silica fume on SFRCC are quite different in that the one-way modification of NSF is from interface to bulk paste whereas that of silica fume is from bulk paste to interface. Both two methods improve the microstructure and performance of SFRCC effectively. Combination usage takes full advantage of the two modification methods, matches the improvement of different micro zones by two-way modifications, improves the interfacial bond properties and thereby achieves the further enhancement effect on macro performance.

Quantitative evaluation of interfacial transition zone of sustainable concrete with recycled and steel slag as aggregate

AbstractUtilizing steel slag and recycled concrete as fine aggregate could save the consumption of natural resource and reduce the environmental pollution. In this work, the effect of steel slag aggregate and recycled aggregate on the compressive strength and chloride migration coefficient of three types of concretes were investigated and compared with natural aggregate. The interfacial transition zone (ITZ) microstructure and the connection between aggregate and bulk cement matrix was determined by using a quantitative backscattered electron (BSE) image analysis, N2 adsorption–desorption and X‐ray diffraction analysis. Results showed that the compressive strength and chloride resistance ability of natural aggregate concrete (NAC) and steel slag aggregate concrete (SAC) was highly dependent on aggregate volume content. The performance of recycled aggregate concrete (RAC) were much poorer than that of SAC and NAC. Pore structure and phase analysis confirmed that the improved properties of SAC can be partially attributed to the densified ITZ. Regarding RAC, a porous ITZ was observed in BSE image and pore structure analysis, which caused a poor compressive strength and a large chloride migration coefficient. It was found that the improvement of chloride resistance ability by using supplementary cementitious materials in NAC was more remarkable than that in SAC.

Investigation on the properties of aggregate-mastic interfacial transition zones (ITZs) in asphalt mixture containing recycled concrete aggregate

Understanding and characterizing the properties of recycled concrete aggregate asphalt mixture (RCAM) is a challenge because there are more complicated aggregate-asphalt mastic interfacial transition zones (ITZs) in RCAM than that in conventional asphalt mixture. In this study, the nanoindentation test, backscattered electron image-analysis (BSE), and energy dispersive spectroscopy (EDS) were selected to identify and investigate the various ITZs in RCAM. According to the nanoindentation analysis, the thickness and elastic modulus of the ITZs change with the different components in recycled concrete aggregate (RCA), and ITZs adjacent to the porous components (i.e., cement mortar and brick) have a greater thickness and a lower elastic modulus. Based on the analysis of BSE images, ITZs of recycled granite and natural limestone are found to have a denser structure and more aggregate particles when compared with cement mortar and brick. The count variations along the EDS scanning line reveals that the element amount of interfacial transition zone is between the coarse aggregate and asphalt mastic. In addition, the increase in the elastic modulus of ITZ indicates a reduced exfoliation degree of asphalt. The aggregate compositions and aggregate morphology can have effects on the ITZ and adhesion between RCA and asphalt. The test results obtained in this study could support a better understanding of ITZs in RCAM and further mechanical modeling research.

Interfacial characteristics of cement mortars containing aggregate derived from industrial slag waste

ABSTRACT In this study, porosity assessment of cement mortars containing Precious Slag (PS) Ball – an industrial waste produced by rapid cooling of slag generated from steel making process by Slag Atomizing Technology – is done by Back-Scattered Electron (BSE) image analysis. PS incorporated mortars were fabricated and subsequently evaluated for compressive strength. BSE images were analyzed by pore segmentation method. Binarization on the images using Otsu’s thresholding method was done followed by the porosity determination. As the interfacial attributes were the primary concern, the porosity was determined from the aggregate surface to the 100 μm width. A total of 24 sections were analyzed and the mean values were plotted. Although the PS Ball incorporated mortar exhibited 10% lower strength at 28-day age, it showed stronger and less porous aggregate- matrix interface between (from particle surface up to 35 μm width) as compared to that of normal mortar containing sand, which is justifiable by the chemical composition of PS Ball attributed to the potential chemical binding. Further, the porosity decreased as the distance from aggregate surface increased. While the use of PS Ball is environmentally friendly, its enhanced interfacial properties with some strength loss of resulting cement mortars encourages its use in sustainable construction materials.

Quantification of silicon carbide grain structure in TRISO fuel by BSE image analysis

The grain structure of the silicon carbide (SiC) layer in tristructural-isotropic (TRISO) fuels has commonly been qualified in fuel specifications based on a qualitative comparison to visual standards to ensure undesirable microstructure are not produced. This approach is inherently dependent on subjective judgement and provides limited data for analysis or comparison. An alternative method to rapidly quantify (i.e., provide a numeric measure of) the grain structure of the SiC layer in TRISO fuels has been developed. This method relies on the identification of silicon carbide grain boundaries based on brightness variation in backscattered electron (BSE) images through the application of automated image processing algorithms. The speed with which the requisite BSE imaging and analysis may be completed enables the practical use of this method on an industrial scale as a part of qualifying TRISO fuel to meet a given specification on silicon carbide grain structure, which is an important parameter for TRISO fuel performance. The method is benchmarked by comparison to prior Electron-Backscattered Diffraction (EBSD) results for TRISO particles from the Advanced Gas Reactor (AGR) program.

Effects of brass coating and nano-SiO2 coating on steel fiber–matrix interfacial properties of cement-based composite

This study focused on the effects of steel fiber coatings on the interfacial properties of a fiber-reinforced cement-based composite. The impact of a brass coating on the interface between the steel fibers and cement matrix was examined, and the improvement effects of a nano-SiO2 coating and nano-SiO2 powder on both the microstructure and interfacial bond properties were compared. A chemical simulation experiment was designed to analyze the brass coating state in a cement hydration environment. The backscattered electron image analysis (BSE-IA) method was used to conduct quantitative analyses of the calcium hydroxide (CH), porosity, and unhydrated cement (UHC) to investigate the microstructure of the fiber–matrix interfacial transition zone (ITZ). Pull-out tests were conducted to determine the interfacial bond performance, and scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used for micro-observation and element analyses. The results indicated that because of the destruction of the coating structure and the aggregation of CH caused by the dezincification of the brass in a cement hydration environment, the brass coating did not improve (but weakened) the interfacial microstructure and bond performance. Adding the nano-SiO2 powder directly was a useful method for achieving microstructure densification and defect reduction in both the ITZ and bulk paste, while the nano-SiO2 coating provided a more targeted improvement in the fiber–matrix ITZ, particularly near the fibers, leading to a more effective enhancement of the bond performance.

BSE‐IA reveals retardation mechanisms of polymer powders on cement hydration

AbstractThe retardation effects of two polymer powders, styrene butadiene rubber and ethylene‐vinyl acetate, on cement hydration and the mechanisms in terms of hydration degree and microstructure characteristics were investigated by the combination of backscattered electron image analysis, scanning electron microscopy, energy dispersive spectrometer, and X‐ray diffraction. Results show that the cement hydration can be significantly retarded by both polymers with the reductions in cement hydration degrees and hydration products thickness. Polymers retard cement hydration by agglomerating the polymer particles on the surfaces of cement grains, forming films in different thickness and bonding the calcium ions in the pore solutions. Consequentially, the formation of C‐S‐H and CH is depressed and the Ca/Si ratios in the hydration product layer are raised. The retardation is enhanced with the increase in polymer content. This work helps understand the retardation effect of polymers on cement hydration in depth, which enables rational development of polymer‐modified cement‐based materials for further applications.

Hydration of Binary Portland Cement Blends Containing Silica Fume: A Decoupling Method to Estimate Degrees of Hydration and Pozzolanic Reaction

Determination of degrees of hydration/reaction of components of blended cementitious systems (i.e., cement and SCMs: supplementary cementitious materials) is essential to estimate the systems’ properties. Although the best methods for determining degrees of reaction of different SCMs have been recommended by RILEM TC238, they rely on either expensive equipment (e.g., nuclear magnetic resonance) or time-consuming sample preparation and data processing (e.g., backscattered electron image analysis). Furthermore, these methods cannot simultaneously characterize degree of hydration of cement and degree of reaction of SCMs. A novel decoupling method, which can simultaneously estimate the degree of hydration of cement and the degree of reaction of silica fume in binary cementitious materials, is proposed in this study. Based on experimentally determined and theoretically validated stoichiometric parameters of cement hydration and pozzolanic reaction, the contents of calcium hydroxide and hydrate water in pastes are expressed as functions of degree of hydration of cement and degree of reaction of silica fume. With the two contents determined by thermogravimetric analysis, the two degrees can be solved mathematically. It is found that in binary binders the incorporation of silica fume affects hydration kinetics of cement, leading to lower ultimate degree of hydration, shorter dormant stage, and faster hydration in the acceleration stage. As a result, the degree of hydration of cement in blended paste is higher at early ages (e.g., 3 days) but lower at later ages (e.g., 120 days) than that in plain cement paste. In a given blended paste, the degree of reaction of silica fume can be tied to the degree of hydration of cement. The decoupling method is promising for rapid estimations of degrees of hydration/reaction of cementitious materials in a blended system, since it does not require expensive characterization tools or complex data processing methods.