CEMENT & CONCRETE COMPOSITES
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2020
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IF 6.257
Woo Sung Yum,Jung-Il Suh,Dongho Jeon,Jae Eun Oh
This study investigated the effect of calcium formate (CF) on the strength development and microstructure of the CaO-activated ground granulated blast furnace slag (GGBFS) system. The main activator (i.e., CaO) was fixed at 4 wt%, and the GGBFS was replaced with CF at 0, 1, 3, and 5 wt%. The use of CF significantly increased the strength of the binder system by inducing (1) more dissolution of GGBFS, (2) greater C–S–H formation although when CF was used over a certain limit (i.e., 3 wt%), the formation of C–S–H began to be disturbed, and most importantly, (3) an increase in C2AH8 formation. In this study, although the greater formation of C2AH8 was the main cause of the strength enhancement, the C2AH8 phase also likely increased porosity and reduced strength as it was metastable; thus, strength increasing effect and reducing effect likely offset each other; thus, with increasing CF dosage, when the former was more dominant, the strength was enhanced (e.g., up to 3 wt%), but when the latter was larger, the strength enhancement decreased (e.g., at 5 wt%).
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
CHEMOSPHERE
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2021
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IF 7.086
Yiming Wang,Jiangyu Wu,Hai Pu
Recycling mining wastes to produce cemented tailings backfill (CTB) is the optimal approach to eliminate the environmental pollution caused by their accumulation. However, its low strength limits its application. Using calcium formate (CF) as an accelerator for improving its mechanical properties is of great significance to promote sustainable development. The effects of CF dosage and curing time on dilatancy deformation, compressive strength and microstructure of CTB were investigated through mechanical compression, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) tests. The strengthening and deterioration mechanisms of CF dosage on CTB were revealed, and its engineering practicability was systematically evaluated. The results show that the variation of volumetric strain in the dilatancy deformation stage firstly increase and then decrease with the increases of CF dosage and curing time. The relationship between CF dosage and compressive strength can be characterized by quadratic polynomial, and the optimal CF dosage characterizing the superior mechanical property of CTB is between 1.60 and 1.84. The supplement of CF reduces the size and distribution of microcracks and micropores, thereby optimizing the microstructure of CTB. Nevertheless, the excessive dosages of CF deteriorate the microstructure of CTB and produce serious defects, which cannot be effectively filled by hydration products, thus weakening the strength property of CTB. This study provides an effective accelerator for improving the mechanical properties of CTB, which is of great significance to promote the recycling of tailings.
研究领域:
矿业工程
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CEMENT & CONCRETE COMPOSITES
·
2024
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IF 10.8
Aidarus Yonis,Yanchen Oinam,Prabhat Vashistha,Aron Berhanu Degefa,Geta Bekalu Belayneh,Solmoi Park,Sukhoon Pyo
This study investigates the environmental and mechanical implications of incorporating silica fume into lime-activated thermo-mechanically treated waste concrete powder (TMWCP) to develop a sustainable clinker-free binder. The novel activation method involves thermo-mechanical treatment of WCP, followed by lime and calcium formate chemical activation. The results demonstrated that incorporating silica fume enhanced the pozzolanic reactivity , which led to the formation of C–S–H, pore refinement, and a dramatic increase in compressive strength . For instance, the incorporation of 20 % and 25 % silica fume exhibited compressive strength of 46 MPa and 43 MPa after 28 days of curing. The developed clinker-free binder with the addition of 20 % silica fume demonstrated a reduction in mineral resource consumption of 99.3 % and CO 2 emissions of 13 % and 69.3 % compared to the sample without silica fume and ordinary Portland cement , respectively. This study offers a promising avenue for the widespread utilization of WCP as an environmentally friendly clinker-free binder.
研究领域:
建筑材料学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
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2020
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IF 4.419
Woo Sung Yum,Jung-Il Suh,Do Hoon Kim,Jae Eun Oh
Recently, the combined use of calcium oxide (CaO) and calcium formate (Ca(HCOO) 2 ) has been proposed as an alternative activator for ground granulated blast furnace slag (GGBFS) (referred to as CaO-Ca(HCOO) 2 -activated GGBFS system). However, this clinker-free binder system produces calcium aluminate hydrate (C 2 AH 8 ), generally leading to the degradation of cementitious binder systems by its conversion to other phases. Thus, in this study, attempts to remove C 2 AH 8 from this system without losing the strength are suggested by the use of two additives (i.e., calcium sulfate (CaSO 4 ) and calcium nitrate (Ca(NO 3 ) 2 ), respectively). Results revealed that the above-mentioned additives completely remove C 2 AH 8 in the initial curing stage via its conversion to ettringite or NO 3 - and NO 2 -AFm, respectively. In addition, the additives reduced the extent of the total shrinkage and the standard deviation of strength results of triplicate samples. However, CaSO 4 exerted a beneficial effect on the strength, while Ca(NO 3 ) 2 exerted a marginal or detrimental effect on the strength. Therefore, this study suggested a new mixture form of an activator, comprising CaO , Ca(HCOO) 2 , and CaSO 4 , to activate GGBFS for maintaining strength without the conversion issue of C 2 AH 8 .
研究领域:
建筑材料学
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材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2019
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IF 2.298
Zisheng Zhang,Xianyi Wang,Jun Ma,Renzhou Bian,Hong Sui,Lin He,Xingang Li
The solubility of calcium formate (form α) in four different binary solvent mixtures (methanol + water, ethanol + water, n-propanol + water, and acetone + water) from 283.15 to 323.15 K was measured by a static equilibrium method under atmospheric pressure. Results indicated that the solubility increased with the increasing temperature and water content in binary mixed solvents. The modified Apelblat equation, the combined nearly ideal binary solvent/Redlich-Kister equation, and the Jouyban–Acree equation were applied for the correlation of experimental solubility, among which the modified Apelblat equation was found to be the best fitting model for the crystallization of calcium formate (form α). This experimental data can be a fundamental guide to choose a suitable crystallization process for calcium formate in industry.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Building Engineering
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2022
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IF 7.144
Yimu Wang,Jinqing Jia,Qi Cao,Xing Gao
The replacement of Portland cement (PC) by fly ash (FA) or slag will cause low early age strength development of concrete. However, the addition of chemical additives can eliminate the well-known drawbacks above. The effect of calcium formate (CF) on the compressive strength development of ternary cement (containing FA and slag) was studied based on simplex centroid design in this paper. Results show that CF can be safely used to increase the strength of ternary cement composite . In addition, the influence of CF on the hydration process and microstructural features of PC and PC-FA/slag blends was investigated using isothermal calorimetry, X-ray diffraction, thermal analysis, and scanning electron microscopy. These results show that the addition of CF can enhance the strength of PC and PC-FA/slag blends at early curing ages, which is mainly because of a kind of calcium aluminate silicate hydrate called gismondine (CaAl 2 Si 2 O 8 ·4H 2 O) and more formation of ettringite (AFt). Furthermore, at later ages of hydration, CF can promote the silicate reaction of PC and PC-FA/slag blends and accelerate the pozzolanic reaction of FA in order to improve the strength.
研究领域:
土木工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Building Engineering
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2023
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IF 6.4
Mandip Dahal,Yanchen Oinam,Prabhat Vashistha,Jae-Eun Oh,Sukhoon Pyo
This study proposes an innovative approach to develop cementless ultra-high performance concrete (UHPC) by activating ground granulated blast furnace slag (GGBFS) without an alkaline-activating solution. To develop cementless UHPC, calcium oxide (CaO) (5% by weight) was used to activate GGBFS, and calcium formate (CF) was used as an accelerator at concentrations ranging from 0 to 6 wt%. The results showed that CF significantly improved the mechanical properties until 5 wt% and all the samples, including CF, exhibited a compressive strength of over 150 MPa. Uniaxial tensile tests revealed strain-hardening behavior, similar to typical cement-based UHPC. The addition of CF led to an increase in hydration products and pore size refinement, resulting in improved mechanical properties. The life cycle assessment results indicated that the developed UHPC mixture had nearly 70% lower CO 2 emission than cement-based UHPC. The experimental results highlight the potential of this method for sustainable UHPC development.
研究领域:
土木工程
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
BIORESOURCE TECHNOLOGY
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2020
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IF 7.539
Kai Li,Guan Zhang,Ze-xiang Wang,Bin Hu,Qiang Lu
An efficient process was developed to selectively produce monocyclic aromatic hydrocarbons (MAHs) from ex-situ catalytic fast pyrolysis (CFP) of pine assisted with calcium formate (CF) over bimetal-modified HZSM-5. Mo and another metal (Mg, Ga or Zn) were used to modify the HZSM-5, and the as-synthesized bimetal-modified HZSM-5 catalysts were utilized for both pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and lab-scale CFP tests with CF as a hydrogen donor to selectively obtain MAHs. The results revealed that the presence of CF and Mg-Mo modified HZSM-5 (0.5Mg1Mo/HZ) exhibited excellent capability for MAHs production with tiny generation of polycyclic aromatic hydrocarbons (PAHs). The maximum MAHs yield attained 12.79 wt% at 650 °C from Py-GC/MS with the CF-to-pine (CF-to-PN) ratio of 3 and catalyst-to-pine (CA-to-PN) ratio of 11, and became 9.67 wt% from lab-scale device with CF-to-PN and CA-to-PN ratios of 0.5 and 4, respectively. In addition, compared with HZSM-5, 0.5Mg1Mo/HZ possessed better anti-deactivation ability.
研究领域:
化学工程
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能源科学
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生物质转化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Sustainable Cement-Based Materials
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2025
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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
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水泥化学
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无机非金属材料
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建筑材料
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水化动力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF DRUG DELIVERY SCIENCE AND TECHNOLOGY
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2022
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IF 5.062
Yusheng Sun,Peng Zhang,Feng Zhang,Mengyang Pu,Wentao Zhong,Yu Zhang,Yingchao Shen,Baoqi Zuo
Silk fibroin nanofiber hydrogels mimicking the extracellular matrix structure have gained increased attention in the field of tissue engineering. In this study, an amorphous silk fibroin nanofiber solution was prepared using a new dissolving technique. The keys to the dissolving method include the preparation of nanofibrous silk film by dissolving silk in a CaCl 2 -Formic Acid (Ca-FA) solution with subsequent dissolution in a CaCl 2 -Ethanol-H 2 O ternary solution at room temperature. The resulting solution was primarily composed of native silk nano/microfibers, which primarily form amorphous structures. The amorphous silk fibroin nanofiber solution was further processed into an injectable hydrogel through a simple physical blend with polyethylene glycol (PEG). The nanofiber structure and PEG accelerated silk gelation, and the fastest gelation time was 150 s at concentrations of 5% silk and 85% PEG. The morphology, secondary structure, and rheological properties of injectable silk fibroin nanofiber hydrogels were subsequently characterized. Silk gelation was accompanied by a structural transition from random coil to β-sheet, and the resulting injectable hydrogel had an irregular lamellar structure. The antibiotic vancomycin (VANCO) was loaded in the injectable hydrogel, and the release of VANCO from the injectable hydrogel was assessed at pH values of 4.5 and 7.4. The VANCO-loaded injectable silk fibroin nanofiber hydrogel exhibited superior antibacterial properties against bacteria. A cytotoxicity test preliminarily demonstrated that the VANCO-loaded injectable silk fibroin nanofiber hydrogel had good biocompatibility for applications in tissue engineering.
研究领域:
组织工程
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生物材料
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药物递送系统
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生物医学工程
✓ 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）