APPLIED THERMAL ENGINEERING
·
2016
·
IF 3.043
Aihong Du,Huiwen Yuan,Wei Liao,Haobo Zhou,Chunhua Lu,Zhongzi Xu
Cost-effective thermal energy storage materials are vital to the application of solar thermal power plants . One focus of this paper is improving thermal and mechanical properties of the thermal energy storage materials; the second focus lies in reducing the investment cost. On the basis of aluminate cementitious composites with 1 wt% nano-SiO 2 , 1 wt% nano-Cu and 15 wt% Cu powders, we introduced different wt% (0, 5, 10, and 15) of Fe powders to gradually replace 15 wt% Cu powders. The samples were heated at 105, 350, and 900 °C, respectively. As a result, when the content of Fe powders substitution was 10 wt%, volume heat capacity, thermal conductivity and compressive strength of the composites after heat-treatment at 900 °C were up to 2.38 MJ m −3 K −1 , 1.45 W m −1 K −1 , and 73.8 MPa respectively, which were 26.6%, 26.1%, and 24.0% higher than those of the composites with 15 wt% Cu powders. At the same time, the investment of the composites with 10 wt% Fe powders substitution was reduced almost 62.0%, compared with that of the composites with 15 wt% Cu powders. In addition, XRD and MIP were employed to characteristic the mineral phases and the pore structures of the aluminate cementitious composites, respectively.
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
高影响因子
Buildings
·
2022
·Vol. 12
·期 4
·422
·
IF 3.324
Jinqing Jia,Yimu Wang
The interaction effects of four chlorine-free admixtures such as calcium formate (CF), triethanolamine, (TEA), triisopropanolamine (TIPA), and sodium sulfate (SS) on the compressive strength development of Portland cement mortars were investigated based on the design of experiment (DoE). The results showed that both the addition of CF and SS contributed significantly to the strength of cement mortars at early curing age. However, the interaction of CF and SS could hinder their respective positive effect on the strength of cement at 1 d. At later curing ages, CF was still beneficial in improving the late strength of cement, but SS had a negative effect on the strength of cement at 28 d. A negative effect of TIPA on the strength of cement was found at 3 d. However, the positive interactive effect of TIPA and CF was sufficient to offset the negative effect of TIPA on the strength of mortars at 3 d if the dosage of CF exceeded 2%. In addition, TEA had a positive influence on 7 d strength until a turning point was reached and the optimum dosage of TEA was approximately 0.013%.
研究领域:
土木工程
·
材料科学
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2021
·
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
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2021
·
IF 9.297
Zhenhai Xu,Jianming Gao,Yasong Zhao,Shujun Li,Zhaoheng Guo,Xu Luo,Gaofeng Chen
Utilization of high volume ground granulated blast furnace slag (GGBS) to produce cement-based materials (CBMs) meets the requirements of sustainable development. However, high volume GGBS will significantly reduce some properties of CBMs. Incorporation of nanosilica is a potentially feasible approach to solve the problem. In present paper, effects of nanosilica (1 wt%, 2 wt% and 3 wt%) on hydration and microstructure of blended cement incorporating high volume GGBS (80 wt%) have been studied by testing setting time, compressive strength , hydration heat, hydration products and pore structure . Results reveal that nanosilica shortens the initial and final setting time of blended cement by 10.75%–20.56% and 10.45%–23.00%, respectively. Furthermore, nanosilica enhances early hydration heat release rate of cement and GGBS. Meanwhile, nanosilica increases cumulative heat release of blended cement by 23.40%–26.46%. However, nanosilica hinders cement hydration after curing for 7 d. Results of thermal analysis indicate that 80 wt% GGBS significantly reduces the content of chemically bound water, while nanosilica improves the parameter by 1.32%–5.91% at 56 d. Additionally, 80 wt% GGBS increases cumulative porosity by 31.89% at 28 d, but nanosilica decreases cumulative porosity by 3.05% at 28 d. Both high volume GGBS and nanosilica can decrease average pore diameter and enhance microstructure of cement paste . Ultimately, nanosilica increases the 28 d compressive strength by 8.27%–19.23%, which partially compensates for the reduction of compressive strength caused by high volume GGBS. This paper can provide the essential foundation for the theory of nanosilica-modified CBMs with high volume GGBS, help to improve the effective utilization rate of GGBS and realize sustainable development of CBMs.
研究领域:
建筑材料学
·
可持续发展工程
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Fengqi Zhang,Dagang Li,Dongxiang Zhang,Jinzheng Hou,Zilei Zhang,Runchao Tan,Haocun Tan,Xiyan Xu
Uranium extraction from seawater faces several challenges, such as extremely low uranium concentration, hydrogel adsorbents’ structural collapse under seawater pressure, and reduced adsorption efficiency in weakly alkaline conditions. To address these issues, a dual-crosslinked hydrogel matrix (CS/PAA) was developed via a one-step cryo-polymerization strategy. By integrating chemically crosslinked polyacrylic acid (PAA) and ionically crosslinked chitosan (CS), the hydrogel achieved a robust 3D interconnected porous structure with a compressive strength of 134.71 kPa. The introduction of amidoxime (AO) groups into CS/PAA further enhanced uranium adsorption, resulting in the CS/P(AA- co -AO) ionic gel. Notably, this hydrogel retained its porous architecture after ambient drying, offering a low-energy alternative to freeze-drying. The presence of chitosan not only imparts antibacterial properties but also stabilizes the gel structure under seawater conditions. The interconnected macroporous network facilitates rapid mass transfer, enabling an adsorption capacity of 11.92 mg·g −1 after 30 days in natural seawater. This innovative ionic gel, combining enhanced structural stability, environmental adaptability, and low-energy preparation, provides a promising strategy for efficient uranium recovery, addressing key limitations of conventional adsorbents.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2020
·Vol. 35
·期 3
·611-619
·
IF 0.64
Zhang Feng,Bai Yin,Cai Yuebo,Chen Bo,Ning Fengwei
Triisopropanolamine (TIPA) was used as an early strength component to study its effects on mortar strength, cement paste setting time and early hydration characteristic of cement. And the early strength mechanism of TIPA at low temperature of 5 °C was also discussed. The results showed that, at 5 °C, the incorporation of TIPA promoted the condensation of cement paste, shortened the initial and final setting time, and accelerated the strength development of specimens at all ages, among which the strength after 3 d increased significantly. The 1, 3, 7, and 28 d compressive strength ratios of the mortars mixed with 1% TIPA could reach 196%, 179%, 160% and 110% respectively, and the mortar strength after 3 d exceeded that of the contrast sample cured at 20 °C. Under low temperature condition, TIPA could promote the hydration reaction of cement, shorten the induction period and advance the acceleration period. Furthermore, the maximum heat release rate and cumulative heat release quantity would be all increased, and the cumulative heat release of the cement mixed with TIPA hydrated for 12 h and 7 d increased 73% and 38% respectively. TIPA could shorten the nucleation and crystal growth (NG) stage and increase its hydration degree significantly, so it promoted cement hydration reaction. Additionally, the hydration reaction rates in phase boundary reaction (I) phase and diffusion reaction (D) phase were increased, and the duration of I process was prolonged, thereby the development of specimen strength would be accelerated. TIPA did not obviously change the types of hydration products, but increased the content of Ca(OH) 2 in the samples and the degree of cement hydration. After hydration to 7 d, large amounts of hydration products, whose surface was smooth, were formed and bonded into sheets, and the structural density of samples improved significantly.
研究领域:
建筑材料学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2021
·Vol. 14
·期 6
·1347
·
IF 3.623
Moses Karakouzian,Visar Farhangi,Marzieh Ramezani Farani,Alireza Joshaghani,Mehdi Zadehmohamad,Mohammad Ahmadzadeh
Considering the remarkable characteristics of nanomaterials, previous research studies investigated the effects of incorporating different types of these materials on improving the concrete properties. However, further studies are required to evaluate the complementary hybridization and synergistic influence of nanomaterials. In this research, the combined effect of adding nano silica particles (NS) and multi-walled carbon nanotubes (MWCNT) on enhancing both the compressive and flexural strengths of the cement paste was investigated. Moreover, the morphology of the interface between cement paste and aggregates was studied by scanning electron microscopy (SEM). The mixtures were prepared using three different portions of MWCNT and NS. Electron microscopy images indicated a uniform distribution of nanoparticles in the cement matrix, enhanced hydration reactions, and increased density. Based on the experiments’ outcomes, the combined utilization of silica and carbon nanomaterials in the cement paste did not necessarily result in the maximum compressive and flexural strengths. Furthermore, it was observed that the use of higher percentages of pristine NS in the absence of MWCNT can lead to further enhancement of strength properties of the cement paste.Keywords:silica nanoparticles;carbon nanotube;compressive strength;flexural strength
研究领域:
土木工程
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
Materials
·
2023
·Vol. 16
·期 6
·2495
·
IF 3.4
Qian Yang,Cuiyan Li,Haibo Ouyang,Ruinan Gao,Tianzhan Shen,Jianfeng Huang
Porous (Ta0.2Nb0.2Ti0.2Zr0.2Hf0.2)C high-entropy ceramics (HEC) with a dual-porosity structure were fabricated by pressureless sintering using a mixture powder of ceramic precursor and SiO2microspheres. The carbothermal reduction in the ceramic precursor led to the formation of pores with sizes of 0.4–3 μm, while the addition of SiO2microspheres caused the appearance of pores with sizes of 20–50 μm. The porous HECs exhibit competitive thermal insulation (4.12–1.11 W·m−1k−1) and extraordinary compressive strength (133.1–41.9 MPa), which can be tailored by the porosity of the ceramics. The excellent properties are ascribed to the high-entropy effects and dual-porosity structures. The severe lattice distortions in the HECs lead to low intrinsic thermal conductivity and high compressive strength. The dual-porosity structure is efficient at phonon scattering and inhabiting crack propagations, which can further improve the thermal insulation and mechanical properties of the porous HECs.Keywords:high-entropy carbides;pressureless sintering;porous ceramics;thermal conductivity;compressive strength
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POWDER TECHNOLOGY
·
2019
·
IF 3.413
Junqiang Zhang,Xuzhong Gong,Zhi Wang,Junhao Liu,Yanguang Chen,Dong Wang,Guoyu Qian,Chuan Wang
Various factors affecting the high temperature compressive strength (TCS) for the carbide slag-based CaO pellets were systematically examined both experimentally and theoretically. It showed that the spherical CaO particles with microstructure can enhance the TCS of the pellets, and the higher the spheroidization of the particles, the higher the TCS. Inducing H 3 BO 3 can lead to a low-temperature nucleation of CaO particle, inhibit the growth of CaO grain, and thus form spherical CaO particles. The TCS of CaO pellet from Ca(OH) 2 was optimized with the response surface methodology with a highest value of 37.4 MPa. For the CaO pellet from the carbide slag, the TCS under optimal conditions was 39.67 MPa. However, it was found out that an excess of H 3 BO 3 inducer in the CaO pellets from the carbide slag could produce eutectic calcium borate with a low melting point, resulting in a decreased TCS.
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
·
2024
·
IF 7.4
Mingwei Feng,Juan Wang,Shu Liu,Dariusz Wanatowski,Yong Ren
Xanthan gum, as an environment-friendly biopolymer, holds great promise to replace conventional binders for engineering construction. Yet, the impact of curing temperature and relative humidity (RH) on the strength of xanthan gum-treated sand remains uncertain. In this study, xanthan gum-treated sand specimens were cured under different temperatures (20°C-70°C) and RH (10 %-80 %), respectively, until an equilibrium moisture content was reached. Through a series of Unconfined Compressive Strength (UCS) tests, an optimal curing humidity of 40 % was identified for all the testing temperatures. It was also found the UCS at 10 % RH is always slightly higher than that at 70 % RH, and the UCS increases linearly with the curing temperature under the same RH. The mechanisms of the findings were further studied by X-ray Computed Tomography (CT) scan tests and Scanning Electron Microscopy (SEM) tests. The strengthening of xanthan gum-treated sand was attributed to an internal hydrogel effect and an external hydrogel-particle network effect. In particular, the hydrogel breakage at low RH and the small hydrogel volume at high RH contribute negatively to the network effect and thus relatively small UCS at low/high RH. Meanwhile, elevating the curing temperature could trigger the conformation transformation of xanthan gum hydrogels and thicken the shells of hydrogels, both of which contribute positively to the hydrogel and network effects and thus provide a higher UCS.
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
·
2020
·
IF 4.419
Jinfeng Sun,Liang Tian,Zhuqing Yu,Yu Zhang,Chengdong Li,Guihua Hou,Xiaodong Shen
The effects of using different sizes of nano-TiO 2 (NT) on the hydration characteristics of Portland cement with different water to solid ratios (w/s, solid: cement + NT) were investigated in this study. Cement was partially replaced by NT with two sizes, 5 nm and 25 nm, at weight fractions of 0, 0.5%, 1.0%, 1.5% and 2.0%. The compressive strength, hydration products, hydration degree, pore structures and morphologies of the modified cement pastes were systematically evaluated. The experimental results showed that a suitable NT content effectively enhanced the compressive strength of the cement paste, and this enhancement directly depended on the NT particle size. Cement paste mixed with 5-nm NT resulted in a higher compressive strength than 25-nm NT, irrespective of the w/s ratio. The cement paste with a maximum compressive strength at all the curing ages was obtained using a 0.3 w/s ratio and 0.5 wt% of 5-nm NT (which were therefore identified as the optimal NT parameters). The compressive strength of this cement paste increased by 41.4%, 15.9%, 18.7% and 24.35% at 1, 3, 7 and 28 days, respectively, compared to a control sample. For both NT sizes, the w/s ratio and the NT content controlled the compressive strength development of the paste during the early and late ages, respectively. Compared with 25-nm NT, replacing cement by 5-nm NT within the optimum content range was more effective in accelerating cement hydration, increasing the hydration degree, decreasing the crystal size of Ca(OH) 2 , refining the pore structure and densifying the cement paste at the microscale, all of which increased the compressive strength at the macroscale.
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
JOURNAL OF APPLIED POLYMER SCIENCE
·
2023
·Vol. 141
·期 9
·e55028
·
IF 3
Haowei Huang,Liangliang Wu,Gang Wang,Xianjun Wang,Yunchuan Xie
Safe building structures cannot be achieved without reliable waterproofing engineering. To address the susceptibility of concrete materials to water leakage, a low-viscosity stearic acid emulsion has been developed as a waterproofing agent for mortar. By introducing lauric acid, the formation of stearic acid crystals in water could be effectively prevented, resulting in a stearic acid emulsion with a viscosity of only 24 mPa·s. It is found that the best overall performance was achieved when the ratio (R) of lauric acid to stearic acid was 2/3. This emulsion has the least effect on mortar fluidity and setting time. The as-prepared modified mortar possessed the highest compressive strength (127% of the blank) and the lowest water absorption at 48 h (37% of the blank). X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive x-ray spectroscopy (EDS), scanning electron microscopy (SEM), dynamic light scattering (DLS) particle size analysis, and water contact angle measurements were used to investigate the mechanism of stearic acid emulsion's modification. It is determined that the stearic acid emulsions successfully modified the internal and external hydrophobicity of the mortar by chemical action with calcium hydroxide.
研究领域:
建筑材料学
·
化学工程
·
土木工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）