CONSTRUCTION AND BUILDING MATERIALS
·
2017
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IF 3.169
Jinfeng Sun,Hu Shi,Binbin Qian,Zhiqiang Xu,Weifeng Li,Xiaodong Shen
This work investigates the influence of synthetic C-S-H/polycarboxylate(PCE) nanocomposites (CPNs) on the hydration and properties of hydrated cement pastes. HPEG-PCE copolymers exhibiting side chain length of 45 ethylene oxide (EO) units was utilized to synthesize CPNs by precipitating C-S-H from Na 2 SiO 3 and Ca(NO 3 ) 2 in the PCE solution. A Box-Behnken Design (BBD) for the Response Surface Methodology (RSM) was employed to statistically optimize the sizes of the resultant. The prepared CPNs were characterized by particle size distribution (PSD), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR) and thermo gravimetric/derivative thermo gravimetric (TG/DTG) analyses. The influence of CPNs on the hydration properties of cement were assessed and discussed in terms of hydration kinetics, mechanical properties, phase composition and pore structure analysis. The experimental results showed that the optimum synthetic parameters, an experimental temperature of 30.1 °C, reactant flow velocity of 0.63 ml/min and initial volume of PCE solution of 28.5 ml, produced CPNs with a minimum size of 329.12 nm. It was demonstrated that PCE polymers were either grafted on the surface or partially intercalated in the interlayer regions of C-S-H, and their introduction also increased the distance between C-S-H interlayers. Cement hydration was significantly promoted as a result of an increased heat release, even at low CPNs content. The early compressive strength of the mortar significantly improved with increasing CPNs content due to the accelerated cement hydration of the CPNs: the 0.6 wt.% CPNs content improved the compressive strength by 18.97%. Moreover, the inclusion of CPNs is advantageous for pore modification: the total porosity decreased by 25.77% after 3 days. Finally, phase composition analysis confirmed that no new crystalline phase was produced upon CPNs addition.
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高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2021
·
IF 6.141
Feifei Zhou,Ganghua Pan,Renjie Mi,Mimi Zhan
Enhancing the properties of concrete using C-S-H seed has been a challenging task due to its agglomeration in the cement matrix. Here, for ensuring synthetic C-S-H disperse well in the cement matrix, it was first synthesized in situ on fly ash (FA) by co-precipitation method, and the C-S-H grown in situ on FA (C-S-H@FA) was received. And then, its phase composition, morphology and particle size distribution were studied. After that, its effect on the hydration kinetics of cement, and the workability, strength development, pore structure, durability of concrete was explored. The results showed that the hydration of cement can be stimulated more dramatically by C-S-H@FA when compared with C-S-H, as well as the strength development of concrete. Besides, the addition of C-S-H@FA can refine the pores in concrete, and make concrete more compact than incorporating C-S-H. Furthermore, when C-S-H was replaced by C-S-H@FA, the carbonation resistance and drying shrinkage resistance of concrete was improved. Therefore, it can be concluded that the C-S-H grown in situ on FA has better dispersibility than C-S-H in concrete, improving the comprehensive properties of concrete more effectively.
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高影响因子
Journal of Materials Chemistry A
·
2026
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IF 9.2
Chenchen Xiong,Weihuan Li,Jiarui Xing,Shengjun Chen,Yulin Wang,Yang Zhou
Low toughness remains an enduring constraint to cementitious materials. Manipulating calcium silicate hydrate (C-S-H), the “genetic component” of cement, which determines mechanical properties of cementitious materials, presents an attractive strategy for intrinsic toughening. However, the modulation is constrained by small-length scale and limited enhancement. Herein, this work proposes an approach to fabricate nacre-mimetic C-S-H bulk composite with brick-mortar microstructure. The composite exhibits an excellent combination of high flexural strength, toughness and impact resistance, with toughness surpassing pure C-S-H and cement paste by factors of over 1000 times, and even outperforming that of natural nacre, reinforced cement-based materials and existing reported C-S-H-based materials. The nacre-mimetic C-S-H composite also exhibits a 20- to 30-fold increase in impact resistance and flexural strength compared to pure C-S-H, respectively. Multi-scale simulations reveal strengthening and toughening mechanisms, including molecular-scale coordination, nano-asperities, viscoplastic deformation, and crack deflection across micro-macro scales. The developed C-S-H nacre not only achieves remarkably high toughness and broadens the potential for scalable application, but also paves a way for designing advanced bioinspired cementitious and silicate-based materials in structural applications.
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高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2024
·Vol. 149
·期 23
·13759-13771
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IF 3
Li Wenjie,Long Jiangfeng,Liu Sijia,Wang Peng,Xu Linglin,Lai Yong
To assess the feasibility of using C-S–H seeds to boost the anti-mechanical vibration capabilities of concrete, this work evaluated the mechanical properties, hydration kinetics, phase assemblage of hydrates, and pore structure of Portland cement (PC) and slag cement mortars, at varying dosages of C-S–H seeds. Results reveal that the incorporation of C-S–H seeds negatively affects the vibration resistance of neat PC, while it effectively enhances the vibration resistance of slag cement. The addition of these seeds facilitates cement hydration and improves the early mechanical properties, which is evident in the shortened appearance time of the hydration exothermic peak by almost 50%. The remarkable vibration resistance observed in slag cement primarily stems from the synergistic effect between C-S–H seeds and slag. However, the premature formation of the internal microstructure in neat PC due to C-S–H seeds disrupts the stability of mutual construction between hydration products. The findings indicate that C-S–H seeds can be used in engineering to enhance concrete lifespan, reduce road repair expenses, and enhance construction efficiency.
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高影响因子
CEMENT AND CONCRETE RESEARCH
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2026
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IF 14
Zedong Zhou,Hangxi Liu,Juanlong Li,Yiru Yan,George Dan Miron,Barbara Lothenbach,Biwan Xu,Ming Fang,Xiaoli Tan,Bin Ma
Calcium silicate hydrate (C-S-H), the principal binding phase in Portland cement, plays a critical role in the immobilization of heavy metals, yet a quantitative and mechanistic understanding of Cu 2+ uptake by C-S-H remains incomplete. This study investigates the immobilization behavior of Cu 2+ by C-S-H with systematically controlled Ca/Si ratios (0.6–1.6) and develops a thermodynamically consistent sublattice solid-solution model. The C-S-Hs were synthesized under sorption equilibrium conditions and characterized to determine their structural evolution with Ca/Si ratio. Cu 2+ sorption was subsequently examined on pre-synthesized C-S-Hs, combined with spectroscopic analyses to elucidate Cu coordination environments. The results show that Cu 2+ is immobilized predominantly through structural incorporation at low Cu 2+ loadings rather than hydroxide precipitation. With increasing Cu 2+ concentration, Cu 2+ progressively intercalates into the interlayers of C-S-H, partially replacing interlayer Ca 2+ and forming Si-O-Cu linkages associated with Q 2 silicate sites. The Ca/Si ratio strongly controls both uptake capacity and binding mechanism. High Ca/Si ratios promote silicate-chain polymerization through conversion of Q 1 to Q 2 units, whereas extremely low Ca/Si ratios induce redistribution between Q 2 and Q b 2 species. At intermediate Ca/Si ratios, Cu 2+ is mainly stabilized as hydroxyl-associated species. Once the sorption capacity is exceeded, excess Cu 2+ transforms into CuO under alkaline conditions. Based on these observations, a CASH+Cu thermodynamic model incorporating five Cu-bearing endmembers was developed and calibrated using both aqueous and solid-phase data. The model quantitatively reproduces Cu uptake, solution chemistry, and phase assemblages, providing a predictive framework for Cu 2+ retention in cementitious systems.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 35
·16455-16469
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IF 3.553
Zhang Zengqi,Wang Qiang,Zhang Mingzhong,Huang Zongxian,Zhuang Shiyu
The filler effect is the most important physical mechanism of mineral admixtures in the early hydration of cement whose chemical properties greatly affect the precipitation of C–S–H. In this study, calcite, strontianite, magnesite, dolomite, quartz, whewellite and whitlockite were selected as the fillers. The morphology and reaction kinetics of synthetic C–S–H precipitated on the surfaces of different fillers were studied via electron microscopy observations and electrical conductivity and ion concentration measurements. The precipitation rate of C–S–H has a positive correlation with the affinity of Ca 2+ for adsorption on the fillers, which can be explained by the nucleation barrier of C–S–H. Extremely ordered honeycomb-like morphology of the C–S–H is found on calcite and strontianite surfaces, while less regular leaf-like or honeycomb-like C–S–H is found on whewellite and whitlockite. The ordered C–S–H pattern is related to the lattice cleavage of the ionic compound filler. In the case of quartz, C–S–H prefers growth along the tangential direction, which is quite different from the normal-direction growth on ionic compounds. The in-plane growth of C–S–H on quartz is believed to be induced by a layer of loosely physically adsorbed Ca 2+ .
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高影响因子
CEMENT AND CONCRETE RESEARCH
·
2025
·
IF 13.1
Minghui Jiang,Xiao Liu,Shiyu Li,Yurui Xu,Simai Wang,Lei Lu,Xinxin Li,Xinru Sun,Chunlei Xia,Ziming Wang,Suping Cui
The internal water migration within calcium silicate hydrate (C-S-H) in dry environments is considered to be the primary factor affecting the volume stability of cementitious materials. In this research, the in-situ polymerization product of plant polyphenol tannic acid (TA) was applied to modify C-S-H based on an organic-inorganic composite modification method. The chemical structure, microstructure, composition, dimensional changes and water migration characteristics of modified C-S-H were analyzed. Experimental results showed that TA improved the polymerization degree of siloxane chains in the C-S-H nanostructure, with a maximum improvement of 80.70%, and increased the interlayer spacing in the C-S-H structure, confirming the modification of C-S-H at the nanoscale, exhibited by 29 Si Nuclear Magnetic Resonance (NMR), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). This modification by TA optimized the C-S-H nanostructure and microscopic pores, and increased the interlayer and gel pore water content, especially gel pore water increased by 56.53% compared to that of the unmodified C-S-H, revealed by nitrogen adsorption and 1 H LF-NMR. In the dry environment, the blocking and cladding effects of TA on C-S-H effectively inhibited the gel water loss and reduced the drying shrinkage, especially at low TA concentration. This research aims to improve the volume stability of C-S-H by in-situ polymerization product of plant polyphenol, which provides new insights into improving the volume stability of cementitious materials.
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高影响因子
Journal of Building Engineering
·
2024
·
IF 6.7
Baomin Wang,Weigao Ding,Chengcheng Fan,Fei Liu,Wenxin Lu,Haoxiang Yang
C-S-H gel is a complex cementitious system, and the properties present significant difference with various Ca/Si ratios. The immobilization mechanism of three heavy metals in C-S-H gel at various Ca/Si ratios was investigated in this work from the prospect of the physical adsorption and chemical immobilization. Results showed that higher Ca/Si ratios can result in an increase in silicon chain polymerization, and lower BET specific area, and C-S-H gel with various Ca/Si ratios showed the excellent immobilization for heavy metals. Pb(II) and Zn(II) can form hydroxyl complex polyhedra in C-S-H under strongly alkaline environments, and increase the silicon chain polymerization degree similar to the doping of C-S-H gel by Al. However, Cd(II) was immobilized in the C-S-H gel with the formation of a solid solution under the action of ion exchange with Ca(II), rather than in the form of hydroxyl complex polyhedral and cadmium hydroxide coprecipitates. The highest adsorption capacity of Pb(II) was realized in C-S-H gel with a Ca/Si molar ratio of 0.9, reaching 95.6006 mg/g. Pb(II) was mainly immobilized in C-S-H gel via physical and chemical adsorption, and the effect of chemical adsorption tended to be significant as the Ca/Si molar ratio increased. And the formation of Pb 8 Ca(Si 2 O 7 ) 3 can be detected in C-S-H gel with a higher Ca/Si molar ratio.
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高影响因子
CEMENT AND CONCRETE RESEARCH
·
2020
·
IF 8.328
Xin Liu,Pan Feng,Wei Li,Guoqing Geng,Jiale Huang,Yun Gao,Song Mu,Jinxiang Hong
Calcium silicate hydrate (C-S-H), the most important Portland cement hydration product , determines the mechanical properties and durability of cementitious materials . In marine environment, C-S-H often suffers from sulfate attack – one of the most common and severe degradations for concrete. pH is considered as a critical factor in determining the deterioration behavior of C-S-H during sulfate attack, of which the significance may be overlooked. This study focused on the role of pH on the deterioration of C-S-H in terms of the composition and nano/micro structure under sulfate attack. The results show that lowering pH aggravates the decalcification of C-S-H, whereas a strong alkaline condition is beneficial to increase the resistance to deterioration. An increase in the mean chain length together with the proportion of large pores (>10 nm) is observed when C-S-H is subjected to low-pH sulfate attack (pH = 10–12), resulting in a relatively loose structure. The deep analysis on defective tobermorite model reveals that calcium at the interlayer of C-S-H nanostructure is readily removed under sulfate attack, thereby improving the potential of Si-O-Si groups formation and increases the mean chain length of C-S-H.
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高影响因子
CEMENT AND CONCRETE RESEARCH
·
2024
·
IF 10.9
Binmeng Chen,Xu Fang,Yuyang Zhao,Zongjin Li
In recycling and reusing construction waste, carbonation of recycled concrete fine (RCF) has been successfully applied to produce value-added products, such as silica nanoparticles, via the breaking of calcium silicate hydrate (C-S-H) structure and condensation of silicate chains. However, the intricacies of carbonation of RCF with varying calcium to silicon (C/S) ratios and their implications on the size of generated silica nanoparticles remain unknown. In this work, we developed an optimized carbonation method at high water to solid ratio to fabricate silica nanoparticles from C-S-H with different C/S ratios. The particle size of silica nanoparticles was found to gradually decrease with the increased C/S ratio of C-S-H. Since as C/S ratio increased, silicate in Q 3 state shifted to Q 1 state and the silicate chain became shorter, shifting from long-range, disordered to short-range, ordered. As the disordered self-seeding growth of long silicate chains derived from C-S-H continued, the Si-O-Si network of silica nanoparticles became chaotic, leaving more unreacted Si-OH on its surface. On the contrary, the short silicate chains displayed higher possibility of condensation, making nanoparticles with a smaller diameter.
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高影响因子
Materials Today Communications
·
2025
·
IF 4.5
Chengzhen Fu,Hailu Wang,Hongxing Zhan,Yuanbing Li,Shujing Li,Bo Yin
Reducing the Ca/Si molar ratio is critical for optimizing calcium silicate hydrate (C–S–H) materials and enabling the recycling of silicon-rich waste. However, achieving high-performance crystalline C–S–H at Ca/Si < 0.83 remains challenging. This study proposes and systematically investigates a dual-silicon-source strategy, employing both active and inert silicon sources to regulate hydrothermal synthesis. At Ca/Si = 0.6, experimental results demonstrate that increasing the active silicon source content from 0 % to 60 % enhances tobermorite crystallinity by 275 %, decreases thermal conductivity by 26 %, and improves compressive strength by 7.30 MPa. The optimal performance was obtained at a reactive silicon-to-calcium molar ratio of 1.0. These findings confirm that this strategy significantly enhances C–S–H crystallinity and material performance. Mechanistically, the higher reactivity of the active silicon source drives competitive calcium consumption, facilitating the formation of long-chain crystalline C–S–H. This approach demonstrates a scalable pathway for synthesizing high-performance C–S–H under low Ca/Si conditions, offering promising applications in optimizing C–S–H-based materials and the recycling of silicon-rich waste.
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高影响因子
CEMENT AND CONCRETE RESEARCH
·
2025
·
IF 13.1
Haochuan Wang,Xin Liu,Chong Wang,Wei Wang,Jinxiang Hong,Pan Feng
Ultra-early mechanical properties are critical for shotcrete performance, significantly influenced by ettringite and calcium silicate hydrate (C-S-H) formed during the initial hydration stage and free water. This study investigates the individual and synergistic effects of these phases on mechanical behavior using equivalent cement pastes. In this system, cement was entirely replaced with dolomite particles of matching size distribution, with the controlled introduction of free water, ettringite, and C-S-H. The validity of these equivalent systems was confirmed through comprehensive characterization. Mechanical performance was subsequently evaluated using compression, shear, Vickers hardness and nanoindentation tests. Results revealed that free water remarkably weakened the mechanical properties, whereas both ettringite and C-S-H enhanced strength by reducing voids and reinforcing weak particle interfaces. Ettringite primarily contributed to interparticle friction, while C-S-H enhanced cohesion at interfaces including dolomite-dolomite, dolomite-ettringite and ettringite-ettringite contacts. When co-existing, C-S-H formed within the porous ettringite network, not only establishing a multi-scale filling structure but also stabilizing the dolomite-ettringite skeleton. These findings advance our understanding of the early-age mechanical development of shotcrete and highlight the potential of equivalent cement systems as robust tools for research into cementitious materials.
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高影响因子
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