Cement Raw Materials Research Articles

Marbles and meta-schists from Bidzar (North Region of Cameroon): characteristics and the use of meta-schists as additives in experimenting blended cements production

Abstract This work presents the petrography and major element composition of marbles and meta-schists found in the Bidzar CIMENCAM marble quarry (North Region, Cameroon). Some of the studied rocks were selected and combined with other characterized raw materials to process schist-blended cements. Marbles are pure (white) or impure (pink, light to dark-grey, or dull yellow…) calcitic, dolomitic, or transitional type, and composed of CaO (32–57 wt%), MgO (0.49–24 wt%), and SiO2 (0.09–8.4 wt%). Meta-schists are bluish-green chlorite meta-schist, chlorite-bearing dark-grey meta-schist, and yellowish-green sericite meta-schist with SiO2 (26–47.3 wt%), Al2O3 (11–16 wt%), Fe2O3 (8–15 wt%), CaO (3–26 wt%), and MgO (4–15 wt%). The used cement raw materials include: clinker, gypsum, marble additive, low CaO bluish-green chlorite meta-schist and low CaO chlorite-bearing dark-grey meta-schist. The two groups of manufactured blended cements mainly composed of CaO (64.2–64.6 wt%), SiO2 (18.0–18.5 wt%), are within the range in ASTM standard, and of some reference cements. The LSF (1.11–1.15), HM (2.6–2.8), SAR (4.6–5.1), SR (2.8–3.1), and AR (1.5–1.7), are within the range of some reference OPC. The proportion of free lime (0.92%–1.25%) is within the range 0.8%–2.25% for reference cement Multi X (CEMIX32.5 R). The proportion of SO3 (1.6%–2.3%,), LOI (8.9%–13.8%), and IR (1.3%–10.6%), are partly close to those of reference cement and other OPC. The BSSA (4794 to 5794 cm2/g) and proportion of retained sieved fractions (4.13 to 11.1%) place the processed cements are within high fineness type. The setting time (130–245 min) seem to satify cement standards. The compressive strength tests show a decrease in strength with the increase in proportion of meta-schist; which could be due to the mineralogical composition of the used cements and their high IR.

Recycling Fly Ash into Lightweight Aggregate: Life Cycle Assessment and Economic Evaluation of Waste Disposal

This study analyzed environmental impacts and economic feasibility to evaluate whether recycling fly ash, which has rarely been addressed in previous studies, as a raw material for lightweight aggregates can be a sustainable waste management alternative. This study presents a comparative analysis of three disposal scenarios: landfill disposal, recycling as cement raw material, and recycling as lightweight aggregate raw material. Nine environmental impacts were assessed through life cycle assessment (LCA): acidification, global warming, eutrophication, photochemical oxidation, stratospheric ozone depletion, human toxicity, freshwater aquatic ecotoxicity, marine aquatic ecotoxicity, and terrestrial ecotoxicity. The results showed that the landfill disposal scenario posed the greatest threat to global warming, eutrophication, and marine aquatic ecotoxicity, while the cement scenario had the greatest impact on stratospheric ozone depletion, human toxicity, and other ecotoxicity items while recycling as lightweight aggregate showed the lowest environmental impacts in most items except acidification and photochemical oxidation. Life cycle costing (LCC) analysis was also performed to compare the economic aspects of each scenario. The lightweight aggregate scenario is more energy-intensive and costly, but it has significant economic benefits due to the significant revenues from the products produced. Therefore, even though the cost is high, this scenario is considered economically advantageous. This study highlights that recycling fly ash into lightweight aggregate reduces environmental impacts, provides economic benefits, and is a better alternative to landfilling and recycling cement raw materials. It will also contribute to promoting sustainable practices of fly ash recycling.

Evaluation of Cretaceous-Tertiary Limestones and Clay for Portland Cement in Erbil, Kurdistan Region of Iraq

Due to the high demand for construction in the Kurdistan Region of Iraq, it is economically natural resources used to minimize importing from other countries, and to increase working hands. Since, limestone is one of the basic raw materials in the cement industry, for this purpose, in the Harir anticline limestone of the Shiranish Formation was mixed with clay of Fatha Formation, in the Shakrok anticline limestone of the Shiranish Formation mixed with clay of Injana Formation, and in the Binabawi anticline limestone of the Shiranish Formation in mixed with clay of the Mukdadiya Formation, dependent on their suitable nearby site locations for factories from each other. The chemical analysis observed by XRF for specifying the major oxides content of CaO, MgO, SiO2, Al2O3, and Fe2O3. three theoretical mixtures of the cement raw materials showed that they have lower liquid content and higher minimum burning temperature in the burning zone, this problem was solved by adding 0.5% iron ore. The Scanning Electron Microscope and Energy-Dispersive by X-Ray spectroscopy carried out for better observation of clinker phase formation showed that the major phases are alite and belite, which indicates suitable burning conditions. Presence of free lime after burning as shown in SEM is due to high CaO content in the limestone raw material.

Estimasi Cadangan Batugamping Menggunakan Block Model Berdasarkan Metode Interpolasi IDW pada IUP OP 231 Karangkemojing

The increasing development of infrastructure development has an impact on the increase in cement demand. Cement is used as the main raw material in making concrete and other construction materials. Therefore, limestone mining as a raw material for cement is also increasing. One of the areas that has prospects for limestone mining is IUP OP 231 Karangkemojing which is still in the exploration stage. The purpose of this study is to determine the geological and geomorphological conditions of the study area, determine the amount of limestone reserves, and determine the estimated mine life based on production targets. The methods used in this research are field observation and laboratory analysis including petrographic analysis and X-Ray Fluorescence (XRF) analysis. Furthermore, the calculation of limestone reserves was carried out using block modeling and the Inverse Distance Weighting (IDW) interpolation method processed using Surpac software. Based on field geological mapping, the research area is included in the wavy hilly and steep hilly structural landforms, which consist of two lithological units, namely sandstone and claystone intermixture units and limestone units. The results of the calculation of limestone reserves in the study area were obtained at 61,444,362 tons with an estimated mine life of about 24 years and 6 months.

Carbon Accounting for Permeable Pavement Based on the Full Life Cycle Approach and Its Application

Conventional pavement in aging communities requires renovation in alignment with global carbon reduction initiatives. This study, centered on upgrading facilities in Guangdong, Hong Kong, and the Macao Greater Bay Area (GBA), utilized the Energy Expert platform to assess the carbon footprint of permeable pavement using life cycle assessment (LCA). The results revealed that the total carbon emission of the 64,065 m2 permeable pavement was 7066.21 tCO2eq. The carbon emission contribution, from highest to lowest, was the production phase, maintenance phase, end-of-life phase, and construction phase. Notably, transportation alone constituted a substantial portion, amounting to 30.15% of total carbon emissions. Compared to traditional pavements, permeable pavement showcased substantial potential for carbon reduction, primarily during the use phase, by enhancing groundwater recharge and mitigating the urban heat island effect, which is critical in reducing the carbon footprint. The estimated total carbon reduction was 853.10 tCO2eq. Sensitivity analysis highlighted diesel energy use in the maintenance phase (51.20%), transportation of cement raw materials in the production phase (45.80%), and transportation of graded gravel for disposal in the end-of-life phase (3.00%) as key factors. Our findings suggest that adopting specific carbon reduction measures, such as substituting gangue for cement binder, transitioning to manual sweeping, and recycling all discarded materials can achieve notable reductions in the respective phases. These findings contribute to a deeper understanding of the role of permeable pavement in reducing carbon emissions, providing insights for the renovation of aging communities.

Multivariable adaptive decoupling control based on stochastic configuration networks with serial-parallel switching distribution

A multivariable adaptive decoupling control scheme is proposed based on stochastic configuration networks with serial-parallel switching distribution (SPSCN). Firstly, a linear controller is designed by combining a PID controller, feedback decoupling, and one-step optimal control. Secondly, a nonlinear controller is presented to deal with higher-order nonlinear terms and unknown external perturbations. SPSCN is used to improve the prediction accuracy of unmodeled dynamics. It combines uniform and normal search strategies in a serial-parallel fashion, aiming at improving the node quality and reducing the model complexity. The approximation performance of the SPSCN algorithm is demonstrated by performing approximation experiments with two functions and four benchmark datasets. Compared with the generalized minimum variance control (GMVC) algorithm in controlling the process of cement raw material decomposition, our proposed control scheme outperforms.

Preparation of Reduced Iron Powder and Cement Raw Material from Red Mud Using Reduction Roasting with CaO

Preparation of Reduced Iron Powder and Cement Raw Material from Red Mud Using Reduction Roasting with CaO

Thermochemical behavior of several common salts blended with cement raw material

Experiments have been conducted to study the thermochemical behavior of common chlorides, sulfates, and alkali salts (CaCl2, CaSO4, K2CO3, Na2CO3, KCl, NaCl, K2SO4, Na2SO4) when blended with cement raw materials at high temperatures, as well as the phenomena of element migration and transformation of Cl, S, K, and Na in the process. The results indicate that little effect was observed on the formation of clinker with the addition of 20% KCl&NaCl and 10% CaSO4. KCl&NaCl were observed to melt at 800°C but completely volatilize at 1100°C, while CaSO4 was not completely decomposed until 1450°C. The addition of 10% CaCl2, 20% K2CO3&Na2CO3, and 20% K2SO4&Na2SO4 resulted in the appearance of the liquid phase of raw materials at 800°C. K2CO3&Na2CO3 predominantly formed complex and stable potassium salts and sodium salts through reactions with raw materials, significantly affecting the formation of C2S and C3S. CaCl2 and K2SO4&Na2SO4 mainly produced liquid phases through melting. CaCl2 completely volatilized after reaching 1250°C, and the molten CaCl2 inhibited the decomposition of CaCO3, thereby inhibiting the formation of C2S and C3S. Although K2SO4&Na2SO4 melted, they only formed stable sulfate salts, without affecting the formation of C2S and C3S.

Evaluation and Analysis of Cement Raw Meal Homogenization Characteristics Based on Simulated Equipment Models.

In recent years, the variability in the composition of cement raw materials has increasingly impacted the quality of cement products. However, there has been relatively little research on the homogenization effects of equipment in the cement production process. Existing studies mainly focus on the primary functions of equipment, such as the grinding efficiency of ball mills, the thermal decomposition in cyclone preheaters, and the thermal decomposition in rotary kilns. This study selected four typical pieces of equipment with significant homogenization functions for an in-depth investigation: ball mills, pneumatic homogenizing silos, cyclone preheaters, and rotary kilns. To assess the homogenization efficacy of each apparatus, scaled-down models of these devices were constructed and subjected to simulated experiments. To improve experimental efficiency and realistically simulate actual production conditions in a laboratory setting, this study used the uniformity of the electrical capacitance of mixed powders instead of compositional uniformity to analyze homogenization effects. The test material in the experiment consisted of a mixture of raw meal from a cement factory with a high dielectric constant and Fe3O4 powder. The parallel plate capacitance method was employed to ascertain the capacitance value of the mixed powder prior to and subsequent to treatment by each equipment model. The fluctuation of the input and output curves was analyzed, and the standard deviation (S), coefficient of variation (R), and homogenization multiplier (H) were calculated in order to evaluate the homogenization effect of each equipment model on the raw meal. The findings of the study indicated that the pneumatic homogenizer exhibited an exemplary homogenization effect, followed by the ball mill. For the ball mill, a higher proportion of small balls in the gradation can significantly enhance the homogenization effect without considering the grinding efficiency. The five-stage cyclone preheater also has a better homogenization effect, while the rotary kiln has a less significant homogenization effect on raw meal. Finally, the raw meal processed by each equipment model was used for clinker calcination and the preparation of cement mortar samples. After curing for three days, the compressive and flexural strengths of the samples were tested, thereby indirectly verifying the homogenization effect of each equipment model on the raw meal. This study helps to understand the homogenization process of raw materials by equipment in cement production and provides certain reference and data support for equipment selection, operation optimization, and quality control in the cement production process.

Enhanced prediction of cement raw meal oxides by near-infrared spectroscopy using machine learning combined with chemometric techniques.

The component analysis of raw meal is critical to the quality of cement. In recent years, near-infrared (NIR) has been emerged as an innovative and efficient analytical method to determine the oxide content of cement raw meal. This study aims to utilize NIR spectroscopy combined with machine learning and chemometrics to improve the prediction of oxide content in cement raw meal. The Savitzky-Golay convolution smoothing method is applied to eliminate noise interference for the analysis of calcium carbonate ( ), silicon dioxide ( ), aluminum oxide ( ), and ferric oxide ( ) in cement raw materials. Different wavelength selection techniques are used to perform a comprehensive analysis of the model, comparing the performance of several wavelength selection techniques. The back-propagation neural network regression model based on particle swarm optimization algorithm was also applied to optimize the extracted and screened feature wavelengths, and the model prediction performance was checked and evaluated using and RMSE. In conclusion, the results indicate that NIR spectroscopy in combination with ML and chemometrics has great potential to effectively improve the prediction performance of oxide content in raw materials and highlight the importance of modeling and wavelength selection techniques. By enabling more accurate and efficient determination of oxide content in raw materials, NIR spectroscopy coupled with meta-modeling has the potential to revolutionize quality assurance practices in cement manufacturing.

Utilization of steelmaking slag in cement clinker production: A review

The cement industry significantly contributes to global CO2 emissions, with a notable portion attributed to limestone calcination during cement clinker production. To promote carbon-neutral building practices, alternative approaches are being explored to replace raw materials in cement manufacturing and mitigate CO2 emissions. Steelmaking slag, enriched with noncarbonated CaO from limestone decarbonization during steel production, shows potential as a promising raw material for cement manufacture to reduce CO2. Despite their environmental benefits, most steelmaking slags are underutilized, with limited recognition of their CO2 mitigation potential. Moreover, challenges to using steelmaking slag as a raw material to manufacture cement clinker exist due to the mineral and chemical compositions of each slag type. This study explored potential pretreatment methods to enhance slag's performance as a cement raw material and the research on utilizing steelmaking slag, including blast furnace slag (BFS), Kanbara reactor (KR) slag, basic oxygen furnace (BOF) slag, electric arc furnace (EAF) slag, ladle furnace (LF) slag, and stainless slag, in cement clinker manufacture. Consequently, steelmaking slag could be used as a raw material to manufacture cement clinker to reduce CO2 emissions. However, additional research is needed, including slag pretreatment methods and cement clinker manufacturing process optimization.

The effect of the combined addition of copper, lithium and sulphur on the formation of Portland cement clinker.

Both copper and lithium act as strong fluxes and lower the temperature of the clinker melt formation. Sulphur promotes the stabilisation of more hydraulically active modification of alite M1. It is expected that this combination could produce an alite clinker at significantly lower temperatures with high quality technological parameters. In this paper, the effect of combined oxides of copper, lithium and sulphur addition on the phase composition and clinker structure of Portland cement was investigated. The reference raw meal was prepared from common cement raw materials. Each of the mentioned oxides was added to the reference raw meal in two different concentrations, and 8 combinations were prepared. Chemically pure compounds (NH4)2SO4, CuO and Li2CO3 were used as a source of these oxides. The raw meals were burned to equilibrium at 1450°C. Their phase composition was determined by X-ray diffraction analysis, the microstructure was monitored by optical microscopy, and the microchemistry of the clinker phases was observed by electron microscopy with EDS analysis. It was found that in samples with high lithium or copper content, there is an increase in belite and free lime at the expense of alite. The combination of Cu + Li has the most negative effect, followed by Li alone and Cu alone. The higher SO3 content slightly offsets this negative effect.

Improvement of the methods for determining ore losses when designing cement raw material deposit mining by surface miner combines

Relevance. The need to optimize production of cement raw materials and reduce the cost of processing raw materials. A surface miner combine allow high selective mining of a deposit, which helps to reduce moisture content of cement raw materials and reduce energy costs in a cement plant. In open-cast mining of cement raw materials deposits with the use of the surface miner combines, the increase in economic efficiency of mining operations can be achieved by determining the rational values of ore losses and dilution. Aim. To determine rational level of cement raw material losses during field development by surface miners. Objects. Cement industry quarries excavated with of the surface miner combines. Methods. Technical and economic analysis of the cement plant Beočin (Serbia), summation and synthesis of materials, sources and data available in the public domain, as well as calculations to determine the amount of loss and dilution of mineral resources at ore–rock contact for mining conditions of the quarry for extracting cement raw materials. Results. The main problems that arise during mining quarries for extracting cement raw materials have been identified. It concerns the determination of the volume of losses and dilution of mineral resources at the ore–rock contact for mining conditions of the quarry for extraction of cement raw materials. The authors present and substantiate conclusions about further effective application of optimal mining technology, with the use of the surface miner combines, which allows reducing the cost of production of minerals and specific operating costs of transporting carbonate rocks compared to the traditional technology of mining works at 50–60%.

The Use of Remote Sensing in the Study of Open-pit Mining and the Ecology of Disturbed Lands in Deposits of Cement Raw Materials in the Regions of Russia

Based on the results of remote monitoring, the state of mining operations in quarries for the extraction of mineral raw materials consumed by cement plants in Russia was investigated. The fleet of mining and transport vehicles in operation in cement quarries was studied. The production capacity of each quarry in terms of rock mass and the total production potential of quarries in Russia, estimated at 210 million tons per year, have been determined. The environmental indicators of disturbed lands during the development of mineral deposits for use in the cement industry as a whole are presented.

ОПРЕДЕЛЕНИЕ ПРОИЗВОДИТЕЛЬНОСТИ КАРЬЕРОВ ЦЕМЕНТНОЙ ПРОМЫШЛЕННОСТИ, РАЗРАБАТЫВАЮЩИХ МИНЕРАЛЬНОЕ СЫРЬЕ С ИСПОЛЬЗОВАНИЕМ КОМБАЙНОВ ПОСЛОЙНОГО ФРЕЗЕРОВАНИЯ SM

Introduction. The relevance of the study is due to the need to optimize technological processes in quarries for cement raw materials and increase the reliability and economic efficiency of deposit development. Surface Miner (SM) layer milling machines, allow carrying out thin-layer mining of deposits, to conduct rational use of subsoil, to increase industrial safety. During open-cast mining of cement raw materials deposits using layer milling machines (SM), the increase of economic efficiency of mining works may be achieved by determining rational values of parameters and indicators of the open cast mine. The main aim. To determinate the optimum productivity of cement industry quarries developed with layer milling machines (SM) ensuring increased reliability and economic efficiency of deposit development. Methodology. As the basic methods of research, we used monitoring of technological processes of the quarry, systematic analysis of the structure, characteristics, properties of technological complexes and links of quarries of cement plant Beocin (Serbia) developing complex structure carbonate deposits with the use of layer-milling machines. Dependence of duration of dump truck rides, number of rides per shift and number of dump trucks for 1 milling machine on the distance of rock mass transportation for mining-technical conditions of the quarries at the cement plant Beocin (Serbia) has been determined. Conclusions. Application of (SM) surface miners at cement industry open-pit mines ensures thin-layer mining of rock mass, reduction of ore losses and emissions of pollutants, rational use of subsoil, increase of industrial safety. Number of factors influences Surface Miner productivity: speed of the machine moving in the process of milling, width of the milling band, thickness of the mined layer, physical and mechanical characteristics of the mined rock and applied technological scheme. It is shown that the increase of Surface Miner productivity is achieved when the length of the front is increased, when the cyclic-continuous and continuous technology of deposit mining is used, and the auxiliary technological processes are minimized.

Quality Analysis of Limestone for the Raw Material of Cement Making Industry in Tangofa Village, Bungku Pesisir Sub-district, Morowali Regency

Morowali Regency, Central Sulawesi Province is one of the largest nickel laterite producing areas in the world, on the other hand this area also has abundant limestone potential, one of the areas that has limestone potential is the Tangofa Area, Morowali Regency. The absence of information related to the chemical composition of limestone in the area is the basis for this research. The purpose of this study was to determine the elemental and mineral content of limestone and to determine the quality of limestone as cement raw material based on CaO and MgO content. The research method was carried out with several stages, namely: literature study, field data collection, and laboratory analysis (Petrography, XRD, and XRF). From the results of petrographic analysis, it can be seen that the constituent minerals of limestone in the research area are calcite and quartz minerals, as well as the results of XRD analysis, which show the presence of calcite minerals that dominate the entire sample with a percentage reaching 100%. The results of analysis with the XRF method can be known oxide compounds constituent limestone in the study area are: CaO, MgO, K2O, PbO, Nb2O5, CuO, Sb2O3, RuO4, SnO2, and In2O3. Rh2O3, TiO2, PdO, and Ag2O. The CaO content of the three samples has a percentage of >48%, while the average MgO content does not exceed 6%, so it can be concluded that the limestone in the study area has good quality for cement raw materials.

Evaluating Thermal Performance and Environmental Impact of Compressed Earth Blocks with Cocos and Canarium Aggregates: A Study in Douala, Cameroon

A novel low-cost earthen construction system integrating biosourced aggregates is proposed for houses’ erection of low-income households. This study is based on in-situ measurements on two representative test cells constructed in Douala, with a typical hot and humid climate. One of these buildings is made with a hollow cement block as a reference, and the other with biosourced earth bricks modified with Cocos nucifera and Canarium schweinfurthii aggregates. Dynamic thermal simulations of the two test cells were performed using the EnergyPlus building performance simulation program. The results are based on measuring air temperature and humidity, and the simulation leads to defining the discomfort hours and the annual energy consumption. The adaptive ASHRAE 55 thermal comfort model was used to evaluate the comfort conditions. The results show that air conditioning systems provide the best comfort systems with minimums of about 95% for plastered and unplastered wall construction systems. Biosourced compressed earth brick constructions offered the best thermal performance with comfort ranges of around 96% and 44% for air conditioning and natural ventilation, respectively. In terms of energy consumed, there was a gain of about 100 kWh over the year. Energy consumption is lower in the biosourced compressed earth brick building than in the hollowed cement block building: this one offered the lowest comfort range of about 40% in natural ventilation. The construction provisions were considered for the life cycle assessment, and two scenarios describing the origin of the cement raw materials were considered. It can be seen that cement accounts for more than 95% of the impacts for both construction systems, as well as for the scenarios of its origin. In all situations, the hollowed cement block construction presented the highest impact on the global warming potential: 66 KgCO2eq and 89 KgCO2eq, respectively, without plaster and with plaster. It can also be seen that the plastered layer had a carbon footprint (in terms of Green House Gas Emissions (GHG emissions)) of almost 40% on the overall functional unit. Canarium Schweinfurthii and Cocos Nucifera materials accounted for only 1% of the overall impact.

Novel waste bone recovery system for CO2 and SOx utilization in cement plants using microbubble carbonation reactor

Cement has been widely used as a primary building material to construct various types of infrastructure. However, cement plants emit excessive carbon dioxide (CO2) and sulfur oxide (SOx) during calcination of limestone. Animal bone residues can reduce air pollutants as they contain calcium hydroxyapatite (Ca10(PO4)6(OH)2), which can capture and utilize CO2 and SOx. Therefore, brushite cement (CaHPO4∙2 H2O) and raw materials of cement, such as calcium carbonate (CaCO3) and calcium sulfate (CaSO4), can be recovered. In this study, a novel waste bone recovery system for CO2 and SOx utilization using cement plant flue gas was developed using a microbubble carbonation reactor (MCR). The system was designed using a process simulation model with the experimental results of the proposed MCR. Using an MCR with a high carbonation rate increases economic feasibility by decreasing the capacity of the conventional cost-intensive carbonation process. The proposed model involves the following steps: (1) waste bone dissolution and synthesis of CaHPO4∙2 H2O; (2) SOx capture and utilization; (3) CO2 capture and utilization using MCR. The total annualized cost (TAC) was determined to validate the economic feasibility of the system. Consequently, 99% of SOx and 94% of CO2 were captured using the production of CaSO4 and CaCO3 at the MCR, respectively. Additionally, the TAC of the proposed system can be decreased by 44% and 27% compared to the base cases 1 and 2 corresponding to the conventional SOx and CO2 capture processes.

Uniaxial tensile study of calcium aluminosilicate hydrate (C-A-S-H): Structure, dynamics and mechanical properties

Calcium aluminosilicate hydrate (C-A-S-H) is the main hydration product of environmentally friendly concrete, which uses aluminum-rich industrial waste residue to partially replace cement raw materials. In order to understand the structure and properties of C-A-S-H gel at the molecular level. The structure, dynamics and mechanical properties of C-A-S-H gel at different Al/Si ratios were studied by reactive molecular dynamics simulation. The results showed that the doping of aluminates substances caused changes in the silicate-aluminate skeleton and inter-layer water molecules in C-A-S-H gels. As the Al/Si ratio increased, more water molecules dissociated and associated with Al atoms to produce Al-O(H)-Si and Al-OH. In addition, the presence of Al-O-Si chains not only imposed geometrical constraints on the inter-layer water molecules, but also increased the attraction of the substrate for water molecules. Furthermore, the mechanical behavior and deformation mechanism of C-A-S-H gels were investigated based on uniaxial tensile tests. The inter-layer bond strength and stiffness of C-A-S-H gels increased significantly with increasing tensile load and aluminate branching structure.

Improved Prediction of Oxide Content in Cement Raw Meal by Near-Infrared Spectroscopy Using Sequential Preprocessing through Orthogonalization (SPORT)

Near-infrared (NIR) spectroscopy is a nondestructive technique extensively employed in various fields. Despite its advantages, near-infrared spectroscopy still faces significant challenges due to the intricate physical and chemical phenomena that arise from the interaction between light and matter. This interaction typically results in light absorption and scattering, leading to the NIR signal containing comprehensive information about these phenomena’s interactions. Accurate determination of CaCO 3 , SiO 2 , Fe 2 O 3 and Al 2 O 3 in cement raw meal requires minimizing scattering effects from the spectrum, but selecting an appropriate pretreatment technique is often challenging. In this paper, we enhance the predictive ability of NIRS for determining the four oxides in cement raw meal by implementing sequential preprocessing through orthogonalization (SPORT). The SPORT method uses sequential orthogonal partial least squares (SO-PLS) to integrate data blocks obtained from different preprocessing techniques. We compare our method with conventional pretreatment methods for determining the content of four oxides in raw materials of cement using near-infrared spectroscopy. The results suggest that the SPORT method exhibits commendable calibration performance and distinctive characteristics. Moreover, SPORT demonstrates significant preprocessing selectivity, making it effective in addressing the challenges associated with complex interactions in near-infrared spectral analysis. In conclusion, the utilization of SPORT sequential pretreatment in near-infrared spectroscopy shows promising results for enhancing the accuracy and efficiency of determining oxide content in raw materials of cement. The findings of this study help promote the application of near-infrared spectroscopy in the cement industry, especially quality control. Further exploration of the SPORT method’s potential in other materials analysis fields may open new avenues for nondestructive techniques in various scientific disciplines.