JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 105
·期 9
·5929-5943
·
IF 4.186
Jie Ren,Hongfang Sun,Qun Li,Zhenming Li,Xiaogang Zhang,Yanshuai Wang,Linfei Li,Feng Xing
In this research, the effects of natural seawater (SW) on the properties of alkali-activated slag/fly ash (AASF) are studied. AASF prepared with deionized water is set as the reference mixture. The results showed that the use of natural SW resulted in a prolonged setting time and lower heat release, but no obvious impact on the flowability of AASF specimens. The long-term compressive strength became higher when SW was used, whereas the corresponding flexural strength and fractural toughness turned lower. The use of SW induced the formation of new products that were not identified in the reference mixture, such as Cl–hydrocalumite and gypsum. In addition, it is evidenced that the dissolution of fly ash (FA) particles was significantly delayed with the incorporation of SW. All these results were related to the various ions introduced by the natural SW and their interactions with the alkaline activator as well as the precipitation of salts on slag and FA surfaces or in the matrix.
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
CHEMOSPHERE
·
2020
·
IF 5.778
Jie Wu,Jing Li,Feng Rao,Wanzhong Yin
The present work studies consolidation of phosphate mine tailings through alkaline activation process with the addition of slag for adjusting the gel structure. As increasing slag contents in the raw materials, more (Na,K) 2 O–CaO–Al 2 O 3 –SiO 2 –H 2 O (C-A-S-H) and (Na,K) 2 O–Al 2 O 3 –SiO 2 –H 2 O (N-A-S-H) gels were formed in the mine tailings-based mortars. Compressive strength of the mortars increased as increasing the slag contents from 0 to 40%, and then it kept a plateau. Evolution in microstructure of these mortars were characterized through scanning electron microscopy (SEM), X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) measurements. The study provides fundamentals for the co-disposal of phosphate mine tailings with blast furnace slag through alkaline activation process.
研究领域:
建筑材料学
·
环境工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CEMENT & CONCRETE COMPOSITES
·
2022
·
IF 9.93
Ruiquan Jia,Qiang Wang,Ting Luo
Understanding the workability of alkali-activated phosphorus slag (AAPS) pastes is fundamental for their efficient application. This study revealed the novel mutual inhibition mechanism through which the alkali dose and silicate modulus affect the workability of AAPS pastes based on the hydration reaction . The slump loss of NaOH-activated phosphorus slag (NAPS) paste was slow, and that of waterglass-activated phosphorus slag (WAPS) paste was faster because the soluble Si in waterglass accelerated the dissolution of the phosphorus slag (PS). At a moderate waterglass modulus, the slump losses of the WAPS pastes were slow because the moderate [Al]/{[Ca]+[Mg]} ratio in the pore solution minimized the difference in the magnitude of mutual inhibition between Ca, Mg and Al, causing all hydrates to form slowly. However, at higher and lower waterglass moduli, the WAPS pastes exhibited fast slump losses because hydrates with excess elements formed rapidly due to the excessively high or low [Al]/{[Ca]+[Mg]} ratio.
研究领域:
土木工程
·
材料科学
✓ 已验证
DOI
高影响因子
Buildings
·
2024
·Vol. 14
·期 12
·3835
·
IF 3.1
Yang Zheng,Zhi-Yuan Zhang,Yisong Liu,Xiaozhu Zhang,Shaoguo Kang,Leyang Lv,Junbo Zhou
The utilization of silicomanganese slag (SiMnS) as a precursor for alkali-activated materials (AAMs) is considered as an efficient approach for sustainable and eco-friendly large-scale resource utilization. However, sodium silicate solutions account for more than 50% of the production costs and carbon emissions of AAMs. In this study, AAM activators were prepared by silica-containing waste (acid leaching residue of boron mud, BM-AR) and NaOH as raw materials, and were successfully substituted for commercial sodium silicate-NaOH activators. Results indicated that the NaOH dosage had a great effect on the concentration and modulus of the activator. With the appropriate dosage of NaOH (NaOH: BM-AR = 0.4–0.7), suitable moduli of AAM activators can be produced at a wide range of solid/liquid ratios (L/S = 3–4.5) under mild conditions (80–100 °C). The compressive strength of the SiMnS AAM specimens prepared by this activator can reach 68.58 MPa, and its hydration products were mainly hydrated calcium silicate and amorphous silica–alumina gel, indicating the successful preparation of AAM. Calculation showed that the carbon emission of the AAMs prepared in this study was 12.4% and 37.6% of that of OPC and commercial water glass/NaOH-activated AAMs, and the cost was only 67.14% and 60.78% of them. The process achieves the use of waste materials to replace commercial activators, and is expected to be extended to a variety of AAMs raw materials and silica-containing waste. This makes it a highly promising alternative method for the production of AAMs, particularly the ‘just add water’ AAMs.
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
CONSTRUCTION AND BUILDING MATERIALS
·
2021
·
IF 6.141
Jie Ren,Hongfang Sun,Kun Cao,Zhili Ren,Bo Zhou,Wenshen Wu,Feng Xing
A series of experiments were conducted to investigate the effect of seawater on the properties of alkali-activated slag (AAS) binders to seek further potentiality of these binders in marine environments. The experimental results show that on the one hand, seawater may lead to increased setting time, reduced compressive strength after 3 days and a less compact microstructure. On the other hand, however, it could also slightly improve the early age strength, flexural bending strength (after 28 and 56 days) and fractural toughness, and shows almost no impact on the fluidity of AAS binders. Moreover, with the formation of some new hydration products due to seawater mixing, the water absorption and volume of permeable voids had small decreases while the capillary sorptivity obtained a small increase. The concomitant of the acceleration effect due to the presence of salts and hindrance caused by the interaction between the seawater-based alkaline activator and slag make the AAS binding system more complex compared to the distilled water mixed counterparts. The findings of this study reveal the possibility of seawater used as the mixing water for AAS binders in marine or coastal areas.
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
ENVIRONMENTAL POLLUTION
·
2023
·
IF 8.9
Tao Huang,Lulu Zhou,Chun-Hai Yang,Shu-wen Zhang
The alkalinity of CaO is commonly insufficient in alkali-activating raw soils or minerals for the formation of cementation or geopolymerization. In this study, nonthermal plasma (NTP) irradiation was employed to activate traditional CaO to enhance its efficacy in alkali activation and further intensify the self-cementation of gold tailings. The solidification/stabilization (S/S) of the gold tailings-based matrix activated by NTP-CaO was better than that of CaO. The NTP irradiation enhanced the surface hydroxyl groups and oxygen atoms, decreased the binding energy, formed nanoparticles , and significantly changed the morphologies of the calcium activator. The dosage of the NTP-irradiated CaO (NTP-CaO) directly affected the self-cemented solidification/stabilization of gold tailings. The Johnson-Mehl-Avrami–Kolmogorov model was appropriate for analysing the NTP-CaO-activated geopolymerization kinetics of gold tailings. Three-dimensional (3D) structural minerals covered with small pores were determined in the NTP-CaO-activated cemented samples. The employment of NTP-CaO facilitated the formation of aluminosilicate geopolymers during the self-cementation of gold tailings according to comprehensive characterization strategies. The study achieves the efficient self-remediation of gold tailings by activating calcium precursors, which further solves the contradiction between salinization and alkali activation in the field of noncalcined cementitious materials.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2023
·
IF 11.1
Rongrong Zhang,Feng Li,Siqi Zhou,Yue Hou
Volcanic ash has several negative impacts on the environment and can be used in massive to synthesize geopolymers , which are considered quasi-brittle. Carbon nanofibers (CNFs) can reinforce the geopolymers, and the dispersion of CNFs directly determines the reinforcement effect. However, the dispersion of CNFs in alkali solutions is challenging. In this paper, the effect of surfactant type, dosage, and ultrasonic time on CNFs dispersion in aqueous and alkali solutions was investigated by the quantitive method of microscopic image processing to determine the preferred dispersion scheme. Zeta potential tests and visual observation were used to analyze the mechanism and stability. Based on this, volcanic ash-based geopolymer nanocomposites with 0.1 wt% contents of CNFs were synthesized. The mechanical properties were tested, and the microstructure was characterized using Scanning Electron Microscope coupled with Energy Dispersive Spectroscopy and Mercury Intrusion Porosimetry . The results showed that methylcellulose (MC), polycarboxylate superplasticizer (PC), and polyvinylpyrrolidone (PVP) could disperse CNFs in aqueous, but evident aggregations can be observed in the alkali solution. PC performed better than MC and PVP in alkali solutions, with 4.83% aggregation area of the whole image, 86% of 0–100 μm 2 aggregations, and an average aggregation area of 87 μm 2 , beneficial from the comb-like structures. Dispersed CNFs can improve the 28-d flexural and compressive strength of the resulting geopolymer nanocomposite by 23% and 16%, respectively, and refine the pore structure through filling, bridging, and nucleation effects, decreasing the average pore size and porosity by 33% and 15%. This paper will contribute to the resourceful use of volcanic ash to reduce pollution and the higher reinforcement of CNFs in alkali-activated geopolymers.
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
Journal of Building Engineering
·
2024
·
IF 6.7
Jiaqi Zhu,Chang Chen,Xufu Wang,Shaowu Jiu,Yanxin Chen,Yan Liu
Rock wool, as an external wall insulation material, is crucial in improving the energy efficiency of structures. However, a large amount of rock wool furnace slag (RWFS) generated during the production of rock wool panels manufacturing causes environmental problems. To address these issues, this study focuses on the use of waste RWFS as a precursor in alkali-activated cementitious materials. In addition, the effect of anatase nano-TiO 2 (ANT) and rutile nano-TiO 2 (RNT) as an additive to the alkali-activated rock wool furnace slag cementitious materials (AARWFSCMs) was evaluated and quantified. Scanning Electronic Microscope (SEM), Isothermal Conduction Calorimetry (ICC), Fourier-Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD) analysis were used to identify the effects of modulus 1.0–1.8 water glass modulus (Ms; SiO 2 /Na 2 O), 3%–7% Na 2 O content on AARWFSCMs. Experimental tests was conducted to quantify the properties such as the setting time, the fluidity, the compressive strength of AARWFSCMs after hardening. Results found that the optimal content of Ms, Na 2 O content in preparing AARWFSCM were 1.4, 5 % for obtaining 28-d compressive strength of 96.36 MPa. The atomic percentage of Ca/Si of the hydration products in the AARWFSCMs fluctuated within 0.94–1.50. The hydration products were a mixture of C–S–H and C–A–S–H. Moreover, the experimental results illustrated that the nano-TiO 2 , which highly beneficial in improving the compressive strength of AARWFSCMs. The additions of 0.50 % ANT and 0.75 % RNT resulted in increments of 5.9 % and 12.8 % in the 28-d compressive strength of AARWFSCMs, respectively. The obtained results provide a new method of utilization of RWFS and improving the sustainability of the construction industry.
研究领域:
建筑材料学
·
环境科学
✓ 已验证
DOI
高影响因子
CEMENT & CONCRETE COMPOSITES
·
2024
·
IF 10.8
Peiqi Zheng,Kaixuan Zhang,Weize Wang,Jing Wang,Xiuzhi Zhang
To attain a balance between compressive strength and electromagnetic wave absorption performance, this paper combined two electromagnetic wave loss mechanisms (magnetic loss and electrical loss), and prepared an environmentally friendly alkali-activated slag/fly cementitious material (ASFC) using micron graphite (MG) as the absorber and ground granulated blast furnace slag (GGBS) and fly ash (FA) as the precursors. The conductivity, electromagnetic wave absorption characteristics and compressive strength of ASFC with different ratios of GGBS and FA, MG size (800 mesh, 320 mesh, and 100 mesh), and content were investigated. The results indicated that when the ratio of GGBS and FA was 7:3, natural resonance and eddy current loss contributed to electromagnetic waves absorption at 8.2–11.0 GHz and 11.0–15.5 GHz range respectively. Additionally, the conductivity of MG/ASFC showed typical percolation characteristics, with the percolation threshold reached at a dosage of 3 wt.%. In the 8.2–18.0 GHz, the incorporation of MG significantly augmented the conductive loss and polarization loss of ASFC. Furthermore, smaller-size MG was more beneficial for facilitating conductive loss and polarization loss of MG/ASFC among three different sizes. By adding 2 wt.% of MG with 800 mesh, MG/ASFC can achieve a minimum reflectivity of −27.8 dB with a bandwidth of 3.0 GHz (Reflectivity ˂-7 dB). However, when compared to other cement-based absorbing materials reported, the MG/ASFC prepared in this experiment demonstrated better compressive strength and wave absorption properties. This finding contributing to a better understanding of green building materials with electromagnetic radiation protection capabilities.
研究领域:
建筑材料
·
环境科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yan Xia,Zhenye Liu,Zhenhao Song,Ruolin Zhao,Jinpeng Wu,Lei Wang,Jianhua Yan
Municipal solid waste incineration fly ash (MSWIFA) is a hazardous waste with high alkalinity and is rich in heavy metals (HMs) and chlorine. To facilitate resource disposal, this paper proposes recycle MSWIFA as an alkali activator to develop low-carbon and cement-free alkali-activated materials. The designed MSWIFA-activated slag exhibited impressive compressive strength (>70 MPa). The microstructure of the MSWIFA-activated slags was tightly filled with various reaction products, including ettringite, calcium aluminosilicate hydrate (C-A-S-H), and Friedel’s salt. The leaching behaviors of the HMs and chlorine were significantly restricted owing to the chemical fixation of the reaction products and the dense microstructure of the MSWIFA-activated slags. The immobilization of chlorine primarily depended on the formation of Friedel’s salt, and the remaining chlorine could be captured by the positively charged sites of C-A-S-H. The reaction mechanism of the designed MSWIFA-activated slags could be divided into three stages: ettringite precipitation, C-A-S-H formation, and Friedel’s salt generation. This paper provides constructive insights into the resource utilization of hazardous waste and contributes to the development of low-carbon alkali-activated materials.
研究领域:
环境科学
·
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
Keke Sun,Xiaoqin Peng,Shuping Wang,Lu Zeng,Peng Ran,Guangxiang Ji
To inhibit the efflorescence of geopolymers, nano-SiO 2 particles were used as an additive to modify an alkali-activated metakaolin mortar. In this work, the effect of the nano-SiO 2 on the compressive strength, pore structure and ion leaching of geopolymers was investigated. Based on these results, the inhibitory mechanism of the nano-SiO 2 on the efflorescence of the geopolymer mortar was analyzed. The results showed that the nano-SiO 2 improved the compressive strength and inhibited the efflorescence of the geopolymer mortar. The nano-SiO 2 decreased the efflorescence by consuming excessive alkali ions in the pore solution to form an amorphous gel phase, and the negative effect of the efflorescence on the compressive strength was also verified. Moreover, the pore structure and transport properties of the geopolymer were also improved by the addition of the nano-SiO 2 , which reduced the diffusion rate and leaching of the ions.
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
Developments in the Built Environment
·
2025
·
IF 8.2
Jian Zhang,Zhenming Li,Wentao Wang,Yaxin Tao,Yubo Sun,Xiangsheng Chen
Alkali-activated materials (AAMs) emerge as a sustainable alternative to Portland cement binders. Despite their potential, the rheological properties of alkali-activated concrete, particularly their non-linear behaviors, remain underexplored. To bridge this gap, a comparative study was conducted to examine the flow characteristics and shear thinning/thickening tendencies of alkali-activated slag (AAS) concrete. The research began with a detailed evaluation of the setting times of AAS mixtures, optimizing activator compositions to identify formulations suitable for concrete productions. Employing the Bingham and Herschel-Bulkley models, it was observed that AAS concrete with a lower silicate modulus (Ms) predominantly exhibited shear-thinning behavior. As the Ms increased, a shift toward shear-thickening behavior occurred, becoming more pronounced with higher concentrations of alkaline compounds in the activators. Furthermore, the fresh properties of AAS concrete significantly improved with increased alkali dosages in the activators, resulting in reduced dynamic yield stress and plastic viscosity, along with enhanced workability retention over time.
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
危险品化学品经营许可证（带存储）