To elucidate the mechanistic influence of alkanolamines with distinct molecular structures on steel slag hydration, this study deconstructs the hydration process into discrete dissolution and precipitation stages. A combination of conductivity measurements, ICP-AES elemental analysis, and coprecipitation experiments was employed to investigate how structurally varied alkanolamines affect the dissolution–precipitation behavior of steel slag. Results show that the isopropanol groups and the number of amino groups collectively govern the selective complexation ability of alkanolamines toward different metal ions. Specifically, diamine-structured N,N,N′,N'-tetrakis (2-hydroxyethyl)ethylenediamine (THEED) exhibits the strongest complexation capacity, while triethanolamine (TEA) shows the weakest. Alkanolamines containing isopropanol groups display competitive complexation characteristics in multi-ion systems. Diethanol-isopropanolamine (DEIPA) preferentially complexes Fe3+, whereas ethanol-diisopropanolamine (EDIPA) shows a preference for Al3+. All four alkanolamines inhibit the precipitation of portlandite (CH) and ettringite (AFt). In contrast, while they have little effect on the participation of Ca2+ in C-S-H formation, they actively promote the incorporation of silicate ions, which consequently lowers its Ca/Si ratio. Owing to its strong affinity for Fe3+, THEED markedly suppresses the precipitation of ferric hydroxide (FH). The enhancement in 3-day compressive strength of steel-slag pastes by alkanolamines is primarily attributed to their ability to promote the dissolution of Ca2+ and Al3+ via complexation, without substantially inhibiting the precipitation of hydration products. Among the four alkanolamines, DEIPA and EDIPA addition results in higher early strength. These findings provide mechanistic insight into the structure-dependent complexation activation of steel slag and clarify how alkanolamine molecular structure regulates its early hydration behavior.

Inorganic nanoparticles have shown significant potential in overcoming the inherent limitations of conventional epoxy resins, particularly their inadequate stiffness and strength during service. This enhancement has considerably broadened their applicability in various fields of advanced composites. However, a serious challenge remains in enabling them to also exert a toughening effect on the epoxy matrix. In this study, the epoxy resin was toughened by polyethylene glycol (PEG)-modified nano SiO2, and the mechanism and curing kinetics were investigated. The mechanical properties, thermal stability, and dynamic thermo-mechanical properties of the composites were evaluated. Furthermore, the dispersion mechanism of the modified SiO2 in the epoxy resin was probed, and the curing kinetic model of the epoxy composites was established. The results showed that the dispersion of the modified SiO2 in the epoxy resin was improved, and the tensile strength, impact toughness and fracture toughness (KIC) of the epoxy composites were optimized when adding 3 wt

Steel slag (SS), as a major industrial solid waste, has limited application in cementitious materials due to the low hydration activity of its potential reactive minerals (aluminate, ferrite and silicate phases). N, N-Bis(2-hydroxyethyl)-2-aminoethanesulfonic acid sodium (BES-Na), as an alkanolamine-like chelating agent, shows great potential in activating these minerals and accelerateing their hydration. This work investigated the activation mechanism of BES-Na on SS by integrating hydration and chelation analysis. The results showed that 0.5% BESNa (optimal dose) significantly promoted hydration of aluminates, ferrites and silicates, increasing the compressive strengths of hardened SS pastes by 2.40-6.07 MPa (3-56 d) and refining the pore structures of hardened SS pastes. The improvement relied on the chelation of BES-Na: BES-Na formed binary five-ring metal chelates with Al3+ and Fe3+ via the O on -OH and the N on -N(R1)2R2 (strongest chelation for Fe3+, key to ferrites hydration). BES-Na accelerated mineral dissolution via chelating solubilization, transforming the precipitation of hemicarboaluminate (Hc) from a slow solid-solid reaction into an efficient solid-liquid reaction. Chelated metal ions can still form Hc and calcium silicate hydrate (C-S-H) gels, and the formation of massive Hc and C-S-H gels drove strength improvement. However, 1% BES-Na altered the crystal structure of Hc, reducing microporous fractal dimension and thereby weakening its strength contribution. This work provided a feasible approach for activating the hydration activity of SS, laying the foundation for the high-value utilization of SS in sustainable cementitious materials and promoting cleaner application of SS waste.

Steel corrosion is a critical issue impacting the durability and sustainability of concrete structures. To address this challenge, eco-friendly chitosan derivative inhibitors, ferulic acid modified chitosan (CTS-FA) and ferulic acid and cysteine modified chitosan (CTS-FA-Cys), were designed and synthesized using a dual-functionalization strategy to enhance both spontaneous surface film formation and Fe2+ adsorption for effective corrosion inhibition. Based on experiments and theoretical calculations, their corrosion inhibition performance and mechanisms were systematically evaluated. Electrochemical measurements demonstrated that both CTS-FA and CTS-FA-Cys significantly improved the corrosion resistance of steel in simulated concrete pore solution containing 3.5 % NaCl (SCPS-NaCl, pH approximate to 12.5), especially for CTS-FA-Cys, achieving a maximum inhibition efficiency of 95.97 % at 500 mg/L. During immersion for 168-1176 h, the inhibition efficiency of CTS-FA-Cys remained at 83.63-92.35 %, demonstrating superior durability and stability compared to unmodified chitosan (91.28-92.65 % within 12-168 h). Theoretical calculations revealed that both inhibitors formed an adsorption film on the Fe (110) surface by donating electrons to the empty d-orbitals of Fe and forming covalent bonds. Adsorption experiments revealed that both inhibitors effectively adsorbed Fe2+, with a maximum adsorption capacity of 60.12 mg/g (CTS-FA-Cys), and their adsorption behaviors followed the pseudo-second-order (PSO) kinetics and Langmuir isothermal adsorption model. This study aims to provide novel strategies for prolonging the durability of reinforced concrete through innovative design and synthesis of inhibitors with a dual inhibition mechanism.

Despite the growing interest in self-healing technologies, the trigger efficiency of microcapsules containing solid particles has not been systematically investigated. Microcapsules incorporating calcium sulphoaluminate cement (SAC) particles were synthesized via a melt-cooling method. The resulting microcapsules exhibit a well-defined core-shell structure with an average diameter of 996.8 f 28.7 & micro;m, a shell thickness of 60.7 f 28.4 mu m, a core content of 57.4 wt%, and sustained a compressive load of 7.2 f 0.9 N before failure. Trigger efficiency was significantly enhanced from 23.2 f 2.5 % to 80.9 f 5.2 % by optimizing key parameters, including surface modification, matrix strength, hydration duration, and microcapsule shell strength. Environmental durability tests indicated that carbonation, sulfate attack, and freeze-thaw cycles had a negligible impact on trigger efficiency. However, exposure to wet-dry cycles for 28 days reduced the trigger efficiency to 61.1 f 3.1 %. The underlying trigger mechanism was also investigated through Extended Finite Element (XFEM) analysis, which quantified the correlation between the matrix-to-capsule stiffness ratio and the critical rupture stress. Finally, the self-healing performance of mortars incorporating the SAC microcapsules was evaluated. Cracks below 200 mu m were effectively sealed within 24 h. The healing products-primarily CaCO3, ettringite, (AFt), and calcium silicate hydrate (C-S-H) gel, possess good impermeability and mechanical strength recovery, confirming the potential of capsules for rapid and efficient self-healing in cementitious systems.

The ultra-low emission transformation of China's cement industry necessitates effective SCR denitration technology, yet complex flue gas conditions cause rapid catalyst deactivation. This study investigates deactivation mechanisms and regeneration of industrial V2O5-WO3/TiO2 catalysts from a 2500 t/d cement production line using combined experimental and computational approaches. Characterization reveals distinct pollutant distributions: top CaCO3 blockage, upper Fe2O3 deposition, and severe lower-layer Tl accumulation (Tl/V > 1). DFT calculations elucidate five differentiated poisoning pathways with quantified energy barriers. CaCO3 forms V4+ polarons; Fe2O3 induces metallization with collapsed band gap; CaSO4 elevates barriers through sulfate spatial hindrance; Fe2(SO4)3 creates competitive dual-site effects; Tl2O achieves maximum poisoning with 3.28 eV NH3 decomposition barrier. An 18-parameter correlation network identifies key descriptors for activity prediction. Regeneration evaluation demonstrates that alkali-acid sequential washing outperforms thermal (Ea: 65.9 kJ/mol) and acid-only (Ea: 56.6 kJ/mol) treatments, achieving near-fresh catalyst performance (Ea: 49.2 kJ/mol). These findings provide engineering guidance for catalyst lifetime management and cost-effective regeneration in cement industry SCR systems.

β-hemihydrate phosphogypsum (β-HPG), as a sustainable and environmentally friendly low-carbon binder, suffers from insufficient long-term strength and durability, which limits its large-scale application. In this study, calcined metakaolin (CMK) with different fineness is used to enhance the key properties of β-HPG. The effects of CMK fineness on workability, mechanical property and durability are systematically evaluated. The results indicate that the incorporation and fineness increase of CMK improve the workability, long-term mechanical strength and durability of β-HPG. In contrast to the reference, the initial (IS) and final setting (FS) times of M6000 are extended by 206.77% and 37.42%, respectively. Meanwhile, the 28 d dry compressive strength, softening coefficient (Kwr), dry-wet strength coefficient (Kdw) and freeze-thaw strength coefficient (Kft) increase 123.51%, 187.50%, 31.38% and 62.17%, respectively. Specifically, the increase in CMK fineness enhances the electrical conductivity and pH of the paste, leading to a higher amorphous phase content (up to 13.90%) and delayed hydration, which promotes the formation of more ettringite (AFt) and gel products that encapsulate the fragile dihydrate gypsum (DH) crystals. Furthermore, CMK addition reduces the T2 relaxation distribution, porosity and pore volume of the hardened matrix. At 28 d, the T2 values of gel and capillary pores in M6000 are 0.86 ms and 0.18 ms, respectively, while the porosity and pore volume decrease by 14.38% and 18.92% compared with the reference. This study proposes an effective design strategy for β-HPG composite binders with improved workability, long-term strength and durability.

Based on the separate grinding process for raw meals in the cement industry, raw meal samples with different particle size characteristics were prepared by controlling the fineness of calcareous components. The results show that the fineness of the calcareous components has a significant influence on the burnability of the clinker and that a critical threshold exists (80 μm sieve residue (R80μm) = 15%). When the particle size exceeds this critical value, the particle size effect becomes dominant, leading to a nonlinear and sharp increase in f-CaO content. As the proportion of coarse particles larger than 200 μm increases, the f-CaO content rises markedly, with a greater impact than that of 80 μm particles. Microscopic analysis of the clinker reveals that with coarsening of the calcareous components (increase in R80μm), alite (C3S) content decreases, whereas belite (C2S) and f-CaO contents gradually increase and exhibit enrichment. Based on diffusion-controlled kinetics, a semi-empirical reaction kinetics model, f-CaO = A·exp(Ea,0+k·R80 μm)RT·(R80μm)n, was developed by introducing the apparent activation energy parameter Ea(R80μm) as a function of particle size. The model exhibited excellent goodness of fit (R2 > 0.95), with an intrinsic activation energy Ea,0 = 18.7 kJ·mol-1 and an incremental coefficient k = 0.28 kJ·mol-1·%-1. Validation experiments yielded a relative error of 4.3%. This model quantifies the coupled effects of temperature and particle size, providing quantitative guidance for balancing grinding energy consumption and sintering energy consumption.

Ferroaluminate cement (FAC) has excellent corrosion resistance, but the influence mechanism of its internal microstructure on water transport is still unclear. In this paper, low field nuclear magnetic resonance ( LF NMR) was used to in-situ quantify the influence mechanism of FAC microstructure evolution on water transport by correcting the interference of FAC on the total distribution of transverse relaxation signals. The results indicate that by adjusting the number of iterations, it is possible to effectively mitigate the interference caused by paramagnetic substances in FAC on the overall distribution of relaxation signals, thereby enabling in situ quantification of FAC microstructure and water transport processes. The total water transport amount and transport time of FAC satisfy the increasing double exponential model, and the surface larger pores and capillary pores dominate the overall water transport process as the fast transport term. When water enters the large pores, the internal transport channel of water is hindered and quickly approaches saturation. In this paper, the interference of FAC on the total NMR signal is corrected, and the influence of FAC microstructure on the water transport process is quantified in situ. It provides new insights for low-field nuclear magnetic resonance technology in the study of water transport in cement-based materials.

The effects of topological structure of polymers on structure, morphology, and seeding effect of polymer/C-S-H nanocomposites were studied by using polyacrylic acid (PAA), comb-like polycarboxylate superplasticizer (CPCE), and star-like polycarboxylate superplasticizer (SPCE). The results showed that intercalation into C-S-H only occurred at high content of the linear polymer. CPCE/C-S-H, in which CPCE only adsorbed on surfaces, showed a foil-like morphology. Differently, SPCE with compact conformation not only adsorbed on the surfaces but also intercalated into the interlayer of C-S-H. SPCE/C-S-H with net-like morphology accelerated cement hydration and exhibited a significant seeding effect, enhancing the compressive strength of mortar by 156.5% (12 h) and 70.6% (1d) respectively. The novelty of this study consists in understanding of the effects of topological structure of polymers on the composition and nano/micro structure of polymer/C-S-H nanocomposites and the interaction between polymers and C-S-H.

Severe thallium (Tl) contamination released from cement kiln flue gas profoundly deactivates commercial selective catalytic reduction (SCR) catalysts, restricting their long-term service stability. Highly volatile Tl species preferentially bind to essential V=O redox active sites to form inert V-O-Tl structures, aggressively disrupting surface acidity and redox synergy. Herein, we report a targeted modification strategy where surface sulfate groups on a Ce(SO4)2-modified vanadium-based catalyst act as sacrificial sites. Even under conditions of severe Tl poisoning, this modified catalyst maintains the NOx conversion rate exceeding 95% within the 350~450 °C, in contrast to the catalytic failure of the unmodified. Tl species preferentially bind and immobilize onto surface sulfate sites of the catalyst, and this targeted capture mechanism spatially and electronically isolates toxic Tl from V active centers. The DFT calculations indicate that the formation of thallium sulfate is thermodynamically more favorable, and this sacrificial trapping mechanism restores surface acid and redox sites, maintaining intact NOₓ adsorption intermediates and unobstructed SCR reaction pathways. This study provides new mechanism regarding the Tl tolerance of SCR catalysts, and these insights for the rational design of highly stable catalysts for industrial NOx removal under complex flue gas conditions.

Thallium (Tl), an extremely toxic and highly volatile heavy metal, has become the primary cause of rapid deactivation of V2O5/TiO2 (VTi) SCR catalysts used in cement kilns. Industrial post-operation analyses consistently show exceptional Tl enrichment on catalyst surfaces—often 2–3 orders of magnitude higher than other heavy metals—resulting in a sharp decline in NOx removal efficiency and raising significant environmental and operational hazards. Motivated by real industrial observations that appropriate amounts of WO3 substantially enhance the Tl tolerance of VTi catalysts, this study provides a mechanistic explanation for both the poisoning pathway and the mitigation effect. We demonstrate that Tl deactivation originates from its strong affinity for VO active sites, where it forms stable V-O-Tl bonds that collapse Lewis acidity, suppress oxygen-vacancy regeneration, and disrupt the V5+/V4+ redox cycle essential for SCR activity. Through multi-scale characterization and DFT analysis, we reveal that WO₃ alleviates Tl toxicity through a dual synergistic mechanism: steric shielding that limits Tl access to vanadium centers, and oxidation of mobile Tl+ to less reactive Tl3+, thereby weakening its ability to bind and deactivate V sites. This cooperative electronic-structural modulation preserves both acidity and redox functionality under realistic high-Tl exposure. The mechanistic insights presented here offer a rational foundation for developing durable, Tl-resistant SCR catalysts tailored for hazardous flue gas environments in cement and waste-incineration industries.

In this study, the retardation mechanism of polycarboxylate (PCE) superplasticisers on cement hydration from the viewpoint of the dissolution-precipitation process was investigated. Effects of PCE superplasticisers on hydration of Portland cement (OPC), C3A (tricalcium aluminate, Ca3Al2O6)-gypsum and pure C3S (tricalcium silicate, Ca3SiO5) and on precipitation of synthetic calcium silicate hydrates (C-S-H) were studied by means of calorimetry and solution analysis. Results show that PCE with a higher charge density and shorter side chain exhibits a stronger retardation effect on cement hydration. The PCE additions inhibit C3S hydration in a similar manner as in the cement pastes, while promoting the depletion of gypsum and secondary hydration of C3A in the C3A-gypsum paste. Furthermore, in OPC systems, the PCE delays C-S-H precipitation without inhibiting dissolution of C3A and C3S, which is responsible for the retardation. Based on the experimental results, a complete view on the retardation mechanism of PCE is proposed: the extension of the dormant period originates from the heightened saturation index required for C-S-H nucleation and growth because of the enhanced stabilisation of C-S-H nuclei by the adsorbed PCE.

The global cement production is approximately 4 billion tons, serving as a fundamental material in socio-economic development. Clinker, a crucial component of cement, is significantly influenced in performance by siliceous materials. Traditional blended grinding results in the enrichment of siliceous materials in coarse particles, thereby affecting burnability. Based on the investigation of the existing raw meal particle size distribution characteristics, a separate grinding technology for siliceous materials is proposed to optimize the raw meal particle size, enhance burnability, and reduce clinker calcination energy consumption. Through laboratory research and industrial trial applications, the effects of separate grinding on burnability and energy consumption are analyzed, and a correlation model of particle size–composition–energy consumption is established. The results show that when the fineness of siliceous materials is controlled to an R80µm of 5–10

Based on the problem of slow early strength development of low-heat Portland cement (LHPC), the effects of various dosages (especially ultra-low dose) of diethanol-isopropanolamine (DEIPA) on the hydration and mechanical properties of LHPC were investigated in this study. Results showed that the effect of DEIPA dosage on strength exhibited a nonlinear relationship, specifically manifested as: trace DEIPA (0.0075

The hydration process of cement is closely related to the quantity and storage capacity of pore water. Quantitative measurement of the spatial distribution of pore water is very important for the study of hydration process. This study improves the low-field nuclear magnetic resonance (NMR) method and proposes a calculation model based on the NMR signal and volume to quantitatively characterize the effects of the spatial evolution of the pore water volume on hydration. The results show that the volume of pore water maintains a non-linear decreasing state during the hydration process. This nonlinear relationship can quantitatively prove the influence of pore water on the hydration process: the initial stage of the hydration process is controlled by the quantity of pore water, and with the extension of hydration time, it gradually changes to the control of pore water storage capacity.

China dominates global NdFeB magnet production (90

Cement products derived from co-disposal in cement kilns have a high content of heavy metal ions (HMs). Long-term environmental exposure risks the leaching of HMs, causing secondary pollution. In this study, aminothiourea combined with tetraethylenepentamine modified chitosan material (ATC) was synthesized and incorporated into cement to immobilize HMs (Zn2+, Cu2+, and Pb2+). The effects of ATC on HMs-containing cement and the stability of HMs within the matrix were systematically examined. Adsorption experiments confirmed the superior capacity and stability of ATC for Zn2+, Cu2+, and Pb2+ uptake under acidic conditions. XPS analysis further indicated that the adsorption mainly involved complexation between HMs and the functional groups (hydroxyl, amino, and thiourea) on the modified chitosan. Furthermore, measurements after 28 days of curing showed more than a 20% reduction in the leaching concentrations of Zn2+, Cu2+, and Pb2+. Adding ATC reduces the proportion of HMs in exchangeable (Q1), carbonate-bound (Q2), and iron/manganese oxide-bound (Q3) states, increases the organically-bound (Q4) proportion, and thus stabilizes HMs in the cement. Mechanical tests showed that ATC increased the compressive strength of HMs-containing mortar by 29.0% and 20.2% at 3d and 7d, respectively. This improvement stems from ATC adsorbing HMs, thereby mitigating their retardation of early cement hydration. XRD patterns and hydration heat results demonstrated that ATC alleviates the early hydration delay and promotes the formation of early hydration products.

Cracks are inevitable during the service of cement-based facilities. The application of microcapsule technology to cementitious materials has realized the self-healing of cracks. In this research, tetraethylenepentamine (TEPA) was successfully encapsulated with polyethylene glycol (PEG)/polyurea shell by integrating melting-dispersion-condensation and interfacial polymerization method. The average diameter of final microcapsules prepared at 300 RPM was 666.9 ± 345.8 μm and the shell thickness was 45.5 ± 1.6 μm. The final microcapsules demonstrated good dispersibility and thermal stability. The normalized strength of the final microcapsules ranged from 0.6 MPa to 1.0 MPa. Moreover, the final microcapsules could remain stable completely both in ambient water and saturated calcium hydroxide (Ca(OH)2) solution for 12 h. Additionally, the final microcapsules remained integral structure during mixing with fresh cement paste and were uniformly dispersed in the hardened cement paste. When microcapsules dosage was 3.0 wt%, the compressive strength of 28 days exceeded 50 MPa and the self-healing rate of compressive strength reached the highest, up to 27.5%. After self-healing, specimens containing microcapsules exhibited excellent resistance to water penetration. The single microcrack of self-healing cement paste with hydration ages of 7 days, 28 days, or even 56 days could be repaired to varying extent and the maximum repairable microcrack width was 145.6 ± 21.6 μm.

Chemical admixtures offer a simple and effective approach to controlling cement hydration. However, achieving both cement paste dispersion and regulation of hydration temperature rise remains a challenge for existing admixtures. A crosslinked polymer (FCMC) was synthesized via copolymerization of acrylic acid and unsaturated carboxymethyl chitosan, and its structure was verified to match the intended design. The effects of FCMC on cement paste performance and its mechanism for regulating temperature rise were investigated. Results show that FCMC (0.2% dosage) significantly enhances cement paste fluidity (increased by 200%) and reduces the peak temperature (decreased by 42.15%) without notably affecting compressive strength. The adsorption and chelation effects of FCMC markedly inhibit crystal nucleation and growth, delay phase boundary reactions, and result in a denser structure with fewer defects. These findings contribute to the innovation and development of admixture structures and provide a theoretical basis for controlling temperature-induced cracking in concrete.