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Silicate hydration is prevalent in natural and technological processes, such as, mineral weathering, glass alteration, zeolite syntheses and cement hydration. Tricalcium silicate (Ca3SiO5), the main constituent of Portland cement, is amongst the most reactive silicates in water. Despite its widespread industrial use, the reaction of Ca3SiO5 with water to form calcium-silicate-hydrates (C-S-H) still hosts many open questions. Here, we show that solid-state nuclear magnetic resonance measurements of (29)Si-enriched triclinic Ca3SiO5 enable the quantitative monitoring of the hydration process in terms of transient local molecular composition, extent of silicate hydration and polymerization. This provides insights on the relative influence of surface hydroxylation and hydrate precipitation on the hydration rate. When the rate drops, the amount of hydroxylated Ca3SiO5 decreases, thus demonstrating the partial passivation of the surface during the deceleration stage. Moreover, the relative quantities of monomers, dimers, pentamers and octamers in the C-S-H structure are measured.
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http://dx.doi.org/10.1038/ncomms10952 | DOI Listing |
Environ Res
September 2025
School of Resources and Safety Engineering, University of Science and Technology Beijing, Beijing 100083, China; Key Laboratory of Safe and Green Mining of Metal Mines with Cemented Paste Backfill, National Mine Safety Administration, University of Science and Technology Beijing, Beijing 100083, Chi
Cemented paste backfill has made outstanding contributions to the large-scale consumption of phosphogypsum (PG), but poor water resistance significantly weakens the mechanical strength, promotes the leaching of total soluble phosphate (TP) and fluoride ions (F), and reduces its attractiveness in mine engineering. This research synthesized a curing agent (CA) using sodium methylsilicate, sodium silicate, and polyaluminum chloride (PAC). PG produced from Deyang Haohua Qingping Phosphate Mine Co.
View Article and Find Full Text PDFEnviron Res
September 2025
Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan, Hubei 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, Hubei 430070, China. Electronic address: yubiao
In order to promote the development and application of low-carbon cement varieties and the recycling of industrial solid waste, this study used iron tailings and fluorogypsum to prepare iron-rich belite-sulfoaluminate cement (I-BCSA). The suitable conditions for the preparation of I-BCSA in this system were with an excessive addition of 6 wt% of SO in the raw meal, at a calcination temperature of 1250 °C for 1.5 h, and an added-gypsum content of 15 wt%.
View Article and Find Full Text PDFPLoS One
September 2025
School of Civil Engineering, Guizhou University, Guiyang, Guizhou Province, China.
Phosphogypsum is an acidic solid waste mainly composed of CaSO₄-2H₂O by-products of the wet process phosphoric acid industry, which has the characteristics of high impurity content, poor stability of stockpiling, but can be utilized in a resourceful way. Phosphogypsum waste utilization can reduce environmental pollution, save resources and create economic value. In order to investigate the fatigue characteristics and the mechanism of dynamic strength change of cement-phosphogypsum-red clay under wet and dry cycles, the cumulative deformation characteristics and the rule of change of critical dynamic stress of the mixed materials were investigated by dynamic triaxial fatigue test, SEM and XRD test, and the mechanism of dynamic strength change was analyzed according to the microstructure and the chemical mineral composition of the mixed materials.
View Article and Find Full Text PDFJ Comput Chem
September 2025
Laboratoire Lorrain de Chimie Moléculaire L2CM, Université de Lorraine CNRS, Nancy, France.
Significant amounts of effluents containing pharmaceuticals residues are released each year in the environment. These residues are responsible for the disruption of the metabolism of organisms. In this study, vermiculite, a low-cost and high specific area clay material, is a best and effective way to remove the micro-pollutants by adsorption.
View Article and Find Full Text PDFJ Colloid Interface Sci
August 2025
School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China. Electronic address:
The greenhouse effect, which affects ecosystems, weather patterns, and global temperatures, has been exacerbated by the increase in air concentrations resulting from the expansion. Direct air capture is a critical component of the strategy to combat climate change and is also essential for carbon capture, utilization, and storage, however, they are currently prohibitively expensive for practical applications, which underscores the necessity of selecting a low-cost material that has exceptional carbon capture efficacy. Considering their straightforward and economical production processes, cementitious materials are recognized as potential candidates.
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