摘要：
The rheokinetics of geopolymer slurry and its fluidity modification methods, as well as modification mechanism were investigated by performing viscosity time dependence experiments and a cement comparative experiment. The results show that the viscosity curve of geopolymer slurry fits well with power law equations. The viscosity time dependence can be employed to characterize the geopolymerization process, and to describe the variations of fluidity with time. K+ activated geopolymer has lower initial viscosity and better fluidity retention than Na+ does. Among superplasticizers, naphthalene-based superplasticizer performs best, but superplasticizers simultaneously promote the deformation of viscosity. Viscosity curve of cement changed unevenly. (C) 2020 Elsevier Ltd. All rights reserved.
摘要：
The effects of calcium content on the molecular structure and mechanical properties of sodium aluminosilicate hydrate (NASH) gels were studied by molecular dynamics simulations. NASH gels with different calcium content were constructed, followed by optimization, equilibration, and production runs of molecular dynamics simulation. Properties such as energy profile, radial distribution function (RDF), distribution of bond length and bond angle, mean square displacement (MSD), elastic modulus and density were obtained. The results indicated that with the increase of Ca/Al, average bond lengths and total energy decreased monotonically, and the distributions of bond lengths and bond angles became narrower. Results from the MSD analysis showed that diffusion degree of both Si and Al in the gels decreased with the increase of the Ca/Al ratio. Furthermore, the elastic modulus, compressive strength and density of the gel systems increased monotonically with the increase of calcium content, and the trend is consistent with experimental findings.
摘要：
The aim of this work is to study the impacts of Na+ and H2O on structural and mechanical properties of coal gangue-based geopolymer by experiment and molecular dynamics. Geopolymers were prepared by coal gangue and mixed solution of NaOH and water glass. Then X-ray fluorescence (XRF) and X-ray diffraction (XRD) were utilized to characterize the main chemical composition and crystalline phase of geopolymer after 28d curing. Moreover, Na2Si2O5 glass was firstly proposed to establish the molecular structure of geopolymers with different Na/Al and H2O/Al. Structural optimization and molecular dynamics simulation were implemented under the specific force field. Simulated XRD pattern, energy and temperature curves, radial distribution function (RDF), hydrogen bond, bond angle distribution, mean square displacement (MSD) and elastic modulus of geopolymer were calculated and analyzed. Results indicated that with the increase of Na+ and H2O content, structure of geopolymer became more stable and mechanical properties were improved significantly. (C) 2020 Elsevier Ltd. All rights reserved.
会议名称：
18th Annual World Environmental and Water Resources Congress of the Environmental-and-Water-Resources-Institute (EWRI)
会议时间：
JUN 03-07, 2018
会议地点：
Minneapolis, MN
会议主办单位：
[Duan, Zhiyong;Xie, Shuibo;Chen, Zhenfu;Wang, Jingsong;Li, Zhi] Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.
会议论文集名称：
World Environmental and Water Resources Congress 2018: Water, Wastewater, and Stormwater; Urban Watershed Management; Municipal Water Infrastructure; and Desalination and Water Reuse
摘要：
Constructed wetlands technology is an important type of wastewater treatment technologies. Compared with other wastewater treatment technologies, the aquatic plants are special components in constructed wetlands for water pollutants removal. However, the comprehensive functions of aquatic plants in constructed wetlands were little emphasized before. In this study, the comprehensive functions and effects of aquatic plants in constructed wetlands to the water pollutants removal are investigated. Multiple common used aquatic plants are compared with their biomass, nitrogen and phosphorus absorption capacity, and oxygen secretion by root systems. These are used to investigate the mechanisms of the functions of aquatic plants in water pollutants removal in constructed wetlands. In this study it is found different types of aquatic plants have different comparable advantages in biomass, nitrogen and phosphorus absorption capacity, and oxygen secretion by root systems. The aquatic plants in constructed wetlands provide dissolved oxygen to the environment around their roots. The aquatic plants themselves have absorption for the nitrogen and phosphorus to directly removal them from the wastewater. Their roots together with the fillers in the constructed wetlands establish the habitat environment for the microorganisms which degrade the water pollutants. The aquatic plants play important and special roles in constructed wetlands for wastewater treatment. These findings can be used for the improvement of the water pollutants removal efficiency in constructed wetlands. The improved constructed wetlands can be used for eutrophication control with higher efficiency.
作者机构：
[王劲松; 林艳; 卢恺; 李霞] Key Laboratory of Pollution Control and Resource Reuse of Hunan Province, University of South China, Hengyang, 421001, China;[周洁] Hunan Heng Kai Environmental Protection Science and Technology Envestment Co., LTD, Changsha, 410000, China;[莫辉艳] School of Construction Engineering Department, Tianhe College of Guangdong Polytechnic Normal University, Guangzhou, 510655, China
通讯机构：
[Wang, J.] K;Key Laboratory of Pollution Control and Resource Reuse of Hunan Province, University of South China, Hengyang, China
