CEMENT & CONCRETE COMPOSITES
·
2024
·
IF 10.8
Aofei Guo,Danying Gao,Zhihui Sun,Hu Feng,Zhenyun Yu,Zeyu Guo,Hong Shang,Fengjuan Liu
Tricalcium silicate (C 3 S) is the primary ingredient in ordinary Portland cement (OPC). Understanding the hydration kinetics of C 3 S with cellulose nanocrystals (CNC) is the key to unveiling the intrinsic mechanism of CNC affecting OPC hydration . This study investigates the hydration interactions between C 3 S and CNC through extensive testing. Findings indicate that CNC incorporation can initially slow the hydration reaction and postpone the early-stage hydration of C 3 S. However, past the initial period (3 days in this study), CNC presence enhances the hydration pace and aids the hydration process , leading to an increase in the formation of calcium silicate hydrate (C–S–H) and calcium hydroxide (CH) without creating new phases. Further, the presence of CNC promotes the homogenous hydration of C 3 S, ensuring a homogenous distribution of hydration products . It also reduces the Ca/Si ratio in the C–S–H, without altering the C–S–H morphology. A correlation is made between heat flow and the thickness of hydration products enveloping C 3 S particles, confirming that CNC can intensify the inward water diffusion rate through C 3 S particles for the same hydration product thickness. Critically, it is found that the effect of CNC on C 3 S hydration is dependent on the water/C 3 S ratio. A low or moderate water/C 3 S ratio can promote C 3 S hydration but a very high water/C 3 S ratio diminishes the beneficial effects of CNC on C 3 S hydration. Finally, the study proposes a explanation for CNC's influence over the hydration of C 3 S with varying water/C 3 S ratios.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2025
·
IF 8
Dandan Yan,Min Li,Chunxiang Qian
Phase change materials are used in cementitious materials to reduce the hydration temperature rise and thus inhibit the temperature cracks generation. However, the influence mechanism of phase change materials on the hydration properties of cementitious materials is still unclear. In this study, ZIF-8-based composite phase change materials (CPCM) were added to the Portland cement (PC) clinker-anhydrite (C$)-calcium sulfoaluminate (CSA) cement ternary system (PCCSA) in the form of admixtures. The effects of controlling the phase change temperatures, dosages of CPCM and hydration temperatures on the hydration exothermic characteristics, hydration products and the compressive strength development in the PCCSA composite system were investigated. CPCM addition reduced the hydration exothermic rate and cumulative heat release of the ternary system, especially when the phase change temperature of CPCM was 25.8 ℃, and the larger the dosage, the more obvious the reduction effect. In addition, CPCM did not participate in the hydration reaction of the system, but promoted the formation of CH and AFm. Simultaneously, the compressive strength of the PCCSA system paste containing CPCM decreased due to increased porosity in the paste. Furthermore, elevated hydration temperature significantly improved the hydration rate of the system, while reduced the hydration degree, and the hydration products types of the system were not affected by the hydration temperatures. This study results are fundamental for predicting the hydration behavior of cement systems containing CPCM and promoting the application of composite phase change materials in cementitious materials.
研究领域:
建筑材料学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2020
·Vol. 103
·期 11
·6505-6518
·
IF 3.502
Pengkun Hou,Xinming Wang,Piqi Zhao,Kejin Wang,Shiho Kawashima,Qinfei Li,Ning Xie,Xin Cheng,Surendra P. Shah
In this paper, C 3 A-gypsum and C 3 A-C 3 S-gypsum model cement systems with and without nanosilica were studied. The effects of nanosilica on the early stage cement hydration, particularly C 3 A hydration, were assessed through the heat of hydration (isothermal calorimetry), phase assemblage (quantitative X-ray diffraction), zeta potential, ion concentration measurements, and morphology (scanning electron microscopy) examinations. The results indicate that while promoting C 3 S hydration, nanosilica retarded C 3 A hydration in both the systems studied. The retardation was caused by the adsorption and coverage of nanosilica on C 3 A surfaces through the electrostatic interaction, thus decreasing the C 3 A dissolution rate and hindering the precipitation of hydration products. Consequently, the reduced gypsum consumption rate and the seeding effect of nanosilica further promoted C 3 S hydration. These findings suggest that nanosilica and other silica-based nanoparticles can physicochemically influence hydration of cement-based materials, and a better understanding of these influencing mechanisms can help optimize performances of nanoparticle-modified cement-based materials.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Bingrong Li,Yaowu Wei,Conghua Peng,Hui Zhou,Shuai Li,Shizhen Wang
The influence of Fe 2 O 3 on the hydration kinetics of tricalcium aluminate (C 3 A) was studied in order to clarify the mechanism of improving hydration resistance of CaO by in-situ synthesized tricalcium aluminate. The Krstulovic-Dabic model was used to investigate the hydration processes of Fe 2 O 3 -C 3 A solid solution and calculate the corresponding kinetic parameters. The hydration products were analyzed by the X-ray diffraction and scanning electron microscope. The results indicated that the Krstulovic-Dabic model simulated the hydration processes of Fe 2 O 3 -C 3 A solid solution at different stages effectively. The hydraulic activity of Fe 2 O 3 -C 3 A solid solution decreased with the addition of Fe 2 O 3 . Reasonable amount of Fe 2 O 3 addition reduced the hydration rate in the initial stage of Fe 2 O 3 -C 3 A solid solution hydration, while the hydration rate of Fe 2 O 3 -C 3 A solid solution was increased with excessive amount Fe 2 O 3 . The hydration process was controlled by multiple mechanisms due to an incomplete layer of hydration products was formed on the surface.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Shuai Li,Yaowu Wei,Bingrong Li,Xiujuan Wang,Junfeng Chen
The phase composition, microstructure, and hydration process of C 3 A with different MgO content were compared to elucidate the mechanism of hydration resistance of CaO improved by MgO–C 3 A solid solution . The process of hydration heat release was detected by isothermal calorimetry and the hydration products were analyzed by X-ray diffraction and scanning electron microscope. The results showed that the addition of MgO resulted in lattice distortion of C 3 A. In the middle and late stages of the hydration process, Mg(OH) 2 and amorphous gel-like substances covered the surface of the unreacted C 3 A and reduced the hydration reaction rate. The addition of MgO effectively reduced the hydration activity of the MgO–C 3 A solid solution that indicated the addition of MgO can improve the hydration resistance of CaO materials.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2017
·
IF 3.169
Jinfeng Sun,Kai Xu,Chaoqi Shi,Jian Ma,Weifeng Li,Xiaodong Shen
TiO 2 @SiO 2 nanoparticles with a core/shell structure widely used in photocatalytic fields were used in this paper to improve the hydration properties of the Portland cement. To this end, the core/shell TiO 2 @SiO 2 nanoparticles were synthesized first and then characterized by a series of techniques including transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR) and X-ray photoelectron spectra (XPS). Second, the influence of the core/shell TiO 2 @SiO 2 nanoparticles on cement hydration was investigated and compared with nano-TiO 2 through isothermal calorimetry, XRD, thermo gravimetric/derivative thermo-gravimetric (TG/DTG) and mercury intrusion porosimetry (MIP) analyses. The results showed that an amorphous SiO 2 layer can be deposited uniformly on nano-TiO 2 particles by forming new Si O Ti chemical bonds at the interface between the SiO 2 coating layer and nano-TiO 2 particle surface. This uniform layer was conducive to decrease the aggregation of nano-TiO 2 effectively. Compared with nano-TiO 2 , the core/shell TiO 2 @SiO 2 nanoparticles exhibited better hydration properties in terms of accelerated cement hydration, higher degree of hydration and lower porosity, even though both particles modified cement hydration.
研究领域:
材料科学
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土木工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Building Engineering
·
2021
·
IF 5.318
Ting Zhang,Baoguo Ma,Hongbo Tan,Huahui Qi,Tao Shi
Both sodium carbonate (NC) and sodium phosphate (NP) could immediately precipitate in the presence of calcium ions (Ca 2+ ), and these precipitates would deposit on the surface of cement as one layer in cement paste . However, these precipitates have different effects on the hydration of cement. In this study, effect of NC and NP on cement hydration was discussed, and the different effect between these two was investigated. Setting time, hydration heat, conductivity of cement suspension , and compressive strength of cement paste were examined, and the hydrates were analyzed with XRD and TG-DTG. The precipitates synthesized in saturated calcium hydroxide solution were characterized with XRD, TEM, and SEM. Then one model was proposed to illustrate the mechanism of the effect of NC and NP on cement hydration. The results indicated that NC accelerated cement hydration, but NP retarded it. And the results of TEM and SEM showed that calcium carbonate (the precipitate formed by NC and Ca 2+ )) could well crystalize with directional growth, there is a large amount of interspace in the calcium carbonate-based layer, which would benefit the transports of water molecules and dissolved ions. However, the calcium phosphate precipitate (the precipitate formed by NP and Ca 2+ )) seemed to have a large amount of amorphous structure with a much more compact layer structure than calcium carbonate. The difference in composition and structure of the layer was responsible for the effect of NC and NP on cement hydration. The mechanism behind accelerating effect of NC was due to the interspace in the calcium carbonate based layer which facilitated the ion dissolution of system, while that for retarding effect of NP was because the calcium phosphate-based layer formed on the surface of cement grains seemed compact enough to restrict the transports of water molecules and dissolved ions. Such consequences were expected to give deeper insight into the effect of the surficial structure of cement grains on early hydration of cement paste.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 83
·44018-44025
·
IF 3.708
Qinyu Ren,Huawei Zou,Mei Liang,Yongmei Wang,Jinchun Wang
A series of comb-like polymer, amphoteric polycarboxylic (APC), was designed as a dispersant for portland cement. APC was synthesized in aqueous solution by macromonomer of butenyl alkylene polyoxyethylene-polyoxypropylene ether (BAPP), sodium methacrylate (SMA), acrylic acid (AA) and [2-(methacryloyloxy)ethyl]trimethylammonium chloride solution (MAEAC). The molecule structure of amphoteric polycarboxylic dispersant was characterized by Fourier transformer infrared (FTIR), and the molecular weight of the APC was determined by gel permeation chromatography (GPC). The dispersion capacity of the APC in cement was also measured. The result shows that the amphoteric polycarboxylic dispersion agent is suitable for portland cement. The APC dispersant with both anionic group and cationic group will provide the better anchoring action with the cement via the adsorption of ions. The hydration mechanism of cement with a certain amount of APC is discussed. We found that the APC could affect the hydration process, which was performed through retarding the generation of ettringite and affecting the crystal enthalpy and its thermal stability in the hydrated product.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2023
·
IF 7.4
Leyang Lv,Shitao Luo,Branko Šavija,Hongzhi Zhang,Lin Li,Tamon Ueda,Feng Xing
The particle size distribution (PSD) has a significant influence on the fresh and final properties of cement and its derived products. In this paper, CSA cements with three different mean diameters (D 50 ), ranging from 6.04 to 26.62 μm were prepared by milling. The pre-hydration behavior was quantitatively analyzed, including the degree of pre-hydration, the dynamic change of mineral assemblage and the morphology of the prepared CSA cement exposed to 57%, 75% and 97% relative humidities (RHs) for up to 90 days. Hydration kinetics, porosity, and compressive strength of the cement paste made with fresh and pre-hydrated CSA cement with different PSD were also characterized. The results show that pre-hydration of CSA cement at RH higher than 75% has detrimental effects on the hydraulic activity and strength gain of CSA cement. However, coarser CSA cement (D 50 = 26.62 μm) does not only show better resistance to pre-hydration, but also higher compressive strength and lower porosity.
研究领域:
材料科学
·
土木工程
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES B-BIOINTERFACES
·
2022
·
IF 5.999
Zidan Luo,Mengfei Tian,Naveed Ahmad,Wu Qiu,Yu Zhang,Chunying Li,Chunjian Zhao
In this study, a switchable temperature-responsive ionic liquid-based surfactant-free microemulsion (TRIL-SFME) for extraction and in-situ separation of hydrophilic and lipophilic compounds from Camptotheca acuminata was firstly developed and systematically characterized. This TRIL-SFME was obtained using 1-hexyl-3-methylimidazolium tetrafluoroborate ([HMIM][BF 4 ]), 1,2-propanediol and H 2 O. The prepared TRIL-SFME presented low viscosity and rapid response to temperature. Firstly, the effect of temperatures on TRIL-SFME phase behavior was studied followed by determination of effect of liquid/solid ratio and extraction time on the extraction yields of the targeted compounds. The TRIL-SFME demulsified rapidly by thermal stimulus, resulting in in-situ separation and enrichment of compounds with varying polarity. The results of present study revealed that TRIL-SFME had higher extraction yields (1.50–5.79 folds) compared to traditional solvents and individual components of TRIL-SFME. Besides, in-situ separation and enrichment of hydrophilic compounds (phenolic acids) and lipophilic compounds (alkaloids) was accomplished in short time (within 3 min) by cooling the system to 4 ℃. Furthermore, the mesoscopic behavior between TRIL-SFME and targeted compounds was simulated by dissipative particle dynamics (DPD) to explore the extraction mechanism for the first time. The results illustrated the formation of W/IL structure of TRIL-SFME and clarified solubilization mechanism of TRIL-SFME system for targeted compounds, which is related to its special "water pool" structure. This novel and switchable TRIL-SFME is an environmentally friendly and promising alternative to simultaneously extract, in-situ separate and enrich the natural active compounds with different polarity from plant matrices.
研究领域:
植物化学
·
分离科学
·
药物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Sustainable Cement-Based Materials
·
2025
·
IF 4.2
Yimu Wang,Jinqing Jia,Dingming Zhang
The effect of low concentration (not exceeding 2%) calcium formate (CF) on the hydration process of tricalcium aluminate (C3A, Ca3Al2O6, the fastest hydrating component in cement)-gypsum systems was investigated in this study using methods such as isothermal calorimetry, XRD, TGA-DSC and SEM. Results demonstrate that a higher dosage of CF corresponds to a more pronounced enhancement in C3A hydration. Furthermore, CF inhibits the initial formation of hydrogarnet (C3AH6, Ca3Al2(OH)12) and promotes the formation of ettringite (AFt) in C3A-gypsum system at 2 h hydration. However, after 1 d hydration, CF facilitates the conversion of excess C3A to C3AH6, which delays the transformation of AFt to AFm. SEM observations reveal that the CF-induced reduction in the size of AFt crystals, formed during C3A hydration, facilitates their more effective filling of interstitial voids within the hydration products, thereby contributing to the formation of a more resilient interlocking structure.
研究领域:
材料科学
·
水泥化学
·
无机非金属材料
·
建筑材料
·
水化动力学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 6
·1023
·
IF 3.164
Lili Guo,Shuang Chao,Pei Huang,Xiukai Lv,Quanquan Song,Chunli Wu,Yuxin Pei,Zhichao Pei
A universal photochemical method to prepare carbohydrate sensors based on perfluorophenylazide (PFPA) modified polydopamine (PDA) for the study of carbohydrate–lectin interactions by a quartz crystal microbalance (QCM) biosensor was developed. The PFPA was immobilized on PDA-coated gold sensors via Schiff base reactions. Upon light irradiation, the underivatized carbohydrates were inserted into the sensor surface, including mannose, galactose, fucose and N-acetylglucosamine (GlcNAc). Carbohydrate sensors were evaluated for the binding to a series of plant lectins. A kinetic study of the interactions between mannose and concanavalin A (Con A), fucose and Ulex europaeus agglutinin I (UEA-I) were performed. This method can eliminate the tedious modification of carbohydrates, improve the experimental efficiency, and reduce the experimental cost, which is of great significance for the development of QCM biosensors and the study of biomolecular interactions.Keywords:perfluorophenylazide;polydopamine;underivatized carbohydrates;QCM biosensor;carbohydrate-lectin interactions
研究领域:
分析化学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）