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.
研究领域:
材料科学
·
土木工程
✓ 已验证
DOI
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.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
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.
研究领域:
土木工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2017
·
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.
研究领域:
建筑材料科学
·
化学工程
✓ 已验证
产品关联
DOI
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.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2024
·
IF 7.4
Xuan Hou,Shuhua Ma,Xiaohui Wang,Yanjun Ou,Ruiping Liu
Industrial waste fly ash was transformed into a fluffy C-S-H (hydrated calcium silicate) material with thermal activation process . The textural property of the material makes it easily integrated and well dispersed in cement using 2% addition. Characterization techniques such as hydration heat, XRD , thermogravimetric analysis , were carried out to elucidate the effect of this C-S-H on cement hydration : the compressive strength of cement mortar was improved beyond 25%; and the viscosity of cement paste was reduced by 22%; the volume of solidified cement expand by 10%. This advances the overall utilization of cement and improve the properties as well.
研究领域:
材料科学
·
水泥化学
✓ 已验证
产品关联
DOI
高影响因子
MRS Communications
·
2023
·Vol. 13
·期 2
·268-275
·
IF 1.9
Qiao Xinfeng,Hu Chuanlin,Yao Shun,Wang Fazhou
This study is to explore the micro-mechanical properties of C–S–H modified by various carbon nanotubes and the correlation with the nano/micro-structures. The results show that carboxyl-functionalized single-walled carbon nanotubes provide the great template for the growth of C–S–H and reduce the porosity and surface defects of C–S–H particles. The highly ordered and dense layered structure of C–S–H greatly improves its micro-mechanical properties. In addition, the functional groups (–COOH) of functionalized carbon nanotubes can combine with the Ca–O bond of C–S–H to change the interlayer spacing of C–S–H, and the effects are particularly significant at low Ca/Si. Graphical abstract
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 35
·16455-16469
·
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+ .
研究领域:
材料科学
·
水泥化学
✓ 已验证
产品关联
DOI
高影响因子
CEMENT & CONCRETE COMPOSITES
·
2023
·
IF 10.5
Zhongtao Luo,Tianyi Zhi,Xiaohai Liu,Kunpeng Yin,Han Pan,Hu Feng,Yatao Song,Yanfeng Su
The early hydration of UHPC can be retarded by the low water/binder ratio, the high polycarboxylate superplasticizers dosage, and the large supplementary cementitious materials (SCM) content. In this study, the effects of the prepared nanoscale C–S–H seeds and nano-silica (NS) on the early performance of UHPC were compared. The mechanism of nanomaterials influencing the early hydration of UHPC was further characterized by calorimetry , thermal analysis, nuclear magnetic resonance (NMR), and mercury intrusion porosimetry . The results showed that the 1-day compressive strength of UHPC samples with 0.3 wt% C–S–H seeds and NS increased by 457% and 25% respectively compared to the control sample. Compared to NS, C–S–H seeds were more effective in accelerating the early (before 3 d) hydration to produce hydrates and refine the pore structure of UHPC. The NMR results further implied that compared with the NS, the C–S–H seeds was 12% and 343% more efficient in accelerating the early hydration of cement and SCMs, respectively. However, the performance enhancement of nanomaterials was effective at 1 d and had little effect thereafter.
研究领域:
土木工程
·
材料科学
✓ 已验证
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2024
·
IF 7.4
Kaifeng Wang,Yuxun Kan,Yunsheng Zhu,Kaihong Zhong,Jiabing Hu
Calcium silicate hydrate (C-S-H) is considered a novel early strength agent, showing immense potential in enhancing the early strength of cement-based materials. Polycarboxylate (PCE) is widely used as a dispersant in the synthesis of nano-C-S-H to prevent agglomeration during synthesis. However, a comprehensive investigation is still required to establish a stable method for preparing stable C-S-H/PCE nanocomposites using chemical co-precipitation. This study employed orthogonal experiments, range analysis, variance analysis, and multi-index matrix analysis to explore the effect of the chemical co-precipitation synthesis process on the stability of C-S-H/PCE nanocomposites. It conclusively identified the calcium-to-silicon (C/S) ratio as the sole significant influencing factor, establishing optimal synthesis parameters: a C/S ratio of 1.6, stirring at 8000 r/min, a 2-hour reaction time, and a reaction temperature of 30 °C. Additionally, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were utilized to investigate the impact of the C/S ratio on the structure and morphology of C-S-H/PCE nanocomposites. Results indicated that under the optimal synthesis parameters, the average particle size and precipitation rate of the synthesized C-S-H/PCE nanocomposites were 0.122 µm and 0.44%, respectively, exhibiting a 4.7% and 47.6% improvement over the best samples in the orthogonal test. Increasing the C/S ratio decreased the crystallinity of the C-S-H/PCE nanocomposites, resulting in the emergence of multiple crystal structures, compact and ordered morphology, and reduced sedimentation. These findings collectively underscore that C-S-H/PCE nanocomposites with higher C/S ratios exhibit enhanced dispersion and stability, validating the rationality of the optimal synthesis parameters identified in this study.
研究领域:
建筑材料学
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2022
·Vol. 32
·期 51
·2208676
·
IF 19.924
Bo Pang,Zuquan Jin,Yunsheng Zhang,Zhiyong Liu,Wei She,Penggang Wang,Yong Yu,Xiaoying Zhang,Chuansheng Xiong,Ning Li,Guowen Sun,Peng Zhao,Guojian Liu,Xiaoyun Song,Song Gao
Cement-based sensors (CBSs) have demonstrated potential in structural health monitoring (SHM) despite rare applications due to their poor flexibility and sensing accuracy/protection with robustness. Herein, a promising strategy is reported to design a waterborne epoxy resin (WEP)-modified cement-based composite coating sensorcapable of simultaneous stable SHM and durable protection. The interpenetrating network (IPN) formed by WEP within cement paste is bionic to the toughness and crack resistance of biological muscle tissue and balances the ion permeation performance and polarization of hydration products. The polymerization-redispersion progress and mechanism of calcium silicate hydrate (C-S-H) gel modified with [3-(2-aminoethylamino)-propyl]trimethoxysilane silsesquioxane (C-POSS) are characterized and revealed. The results show that the muscle-like IPN increases the cement-based coatings’ maximum deflection angle to 30° and improves the monitoring accuracy of compressive, tensile, and fatigue microchanges of concrete structures to more than 95%. The POSS···Ca 2+ ···C-S-H interaction in C-POSS partially transferred the intra-adhesive hydrogen bonds surrounding the nanoconducer into electrostatic bridging ones to maintain an excellent electromechanical conductive dispersion.
研究领域:
土木工程
·
材料科学
·
传感器技术
✓ 已验证
DOI
高影响因子
Journal of Building Engineering
·
2025
·
IF 7.4
Hong Zhou,Shuzhen Zheng,Huina Li,Qianping Ran,Jianfeng Ma
Calcium silicate hydrates (C–S–H) is the primary product of cement hydration, and its structure and properties substantially influence the mechanical performance of cement-based materials. However, in practical applications, pure C–S–H has some shortcomings, such as susceptibility to microcracking and high porosity, which can reduce the durability and overall mechanical performance. To solve these problems, two different sizes of cellulose (microcrystalline cellulose nanoparticles and carboxylated cellulose nanofibers) were used to modify C–S–H nanocomposites, which were synthesized by hydrothermal synthesis. The characterization of the composites was analyzed in detail using methods such as TEM, FT-IR, and TGA. The results of these methods showed that cellulose was uniformly dispersed in the C–S–H matrix on the nanoscale, which formed an interwoven mesh structure. The mechanical properties of the cement paste were tested, including flexural strength and compressive strength. In addition, the cement paste containing the nanocomposites was analyzed by SEM, XRD and hydration heat tests. The results of these tests showed that the seed effect of C–S–H and the effective bridging effect of needle-like cellulose crystals on crack extension significantly improved their mechanical properties.
研究领域:
材料科学
·
土木工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）