scholarly journals Experiment Analysis of Concrete’s Mechanical Property Deterioration Suffered Sulfate Attack and Drying-Wetting Cycles

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Wei Tian ◽  
Nv Han
Keyword(s):  
Inductively Coupled Plasma ◽  
Ct Scanning ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Salt Crystallization ◽  
Ct Number ◽  
Inductively Coupled ◽  
Concrete Deterioration ◽  
Deterioration Process ◽  
Expansion Force

The mechanism of concrete deterioration in sodium sulfate solution is investigated. The macroperformance was characterized via its apparent properties, mass loss, and compressive strength. Changes in ions in the solution at different sulfate attack periods were tested by inductively coupled plasma (ICP). The damage evolution law, as well as analysis of the concrete’s meso- and microstructure, was revealed by scanning electron microscope (SEM) and computed tomography (CT) scanning equipment. The results show that the characteristics of concrete differed at each sulfate attack period; the drying-wetting cycles generally accelerated the deterioration process of concrete. In the early sulfate attack period, the pore structure of the concrete was filled with sulfate attack products (e.g., ettringite and gypsum), and its mass and strength increased. The pore size and porosity decreased while the CT number increased. As deterioration progressed, the swelling/expansion force of products and the salt crystallization pressure of sulfate crystals acted on the inner wall of the concrete to accumulate damage and accelerate deterioration. The mass and strength of concrete sharply decreased. The number and volume of pores increased, and the pore grew more quickly resulting in initiation and expansion of microcracks while the CT number decreased.

scholarly journals Concrete Deterioration and Floor Heave Due to Biogeochemical Weathering of Underlying Shale

1975 ◽  
Vol 12 (3) ◽  
pp. 372-378 ◽  
Author(s):  
P. E. Grattan-Bellew ◽  
W. J. Eden
Keyword(s):  
Porous Material ◽  
Main Product ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Oxidation Reactions ◽  
Concrete Deterioration ◽  
Weathered Zone ◽  
Sulfur Bacteria ◽  
Basement Floor ◽  
Floor Heave

When the basement floor of a church in the New Edinburgh area of Ottawa heaved, it was discovered that the concrete under the floor had been reduced to a mushy consistency due to attack by sulfate solution formed by the oxidation of pyrite in the underlying shale. Gypsum was the main product in the weathered zone of the shale. It is shown that heaving resulted from the growth of gypsum crystals between the lamellae in the shale. Jarosite, which is formed by a series of oxidation reactions from pyrite, was also found in the weathered shale. Some oxidation reactions occur only in the presence of sulfur bacteria. The cementitious portion of the concrete was leached out by acid, leaving a weak porous material. The importance of safeguarding concrete in contact with potentially expansive shales from sulfate attack is emphasized.

Recovery of Nickel from Waste Lithium Ion Secondary Battery and Fabrication of Nickel Nanopowder

2017 ◽  
Vol 733 ◽  
pp. 22-26 ◽  
Author(s):  
Sung Ok Hwang ◽  
Byung Man Chae ◽  
Deuk Hyeon Kim ◽  
Ki Sang Park ◽  
A Ra Go ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Nickel Sulfate ◽  
Lithium Ion ◽  
Optical Emission ◽  
Sulfate Solution ◽  
Precipitation Method ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Solvent Extraction Method ◽  
Nickel Nanopowder

A study on the refining of nickel sulfate solution from sulfuric acid leached solution of spent lithium ion battery and fabrication of nickel nanopowders from the nickel sulfate solution was investigated. the nickel sulfate solution with high purity (>99.9%) was refined by precipitation method and solvent extraction method. the nickel nanopowders were synthesized by liquid phase reduction method with hydrazine and sodium hydroxide. the purity of nickel sulfate solution and nickel nanopowders were measured by EDTA(ethylenediaminetetraacetic) titration method with ICP-OES(inductively coupled plasma optical emission spectrometer). morphology, particle size and crystal structure of the nickel nanopowder was observed using transmission electron microscopy and x-ray diffraction spectroscopy.

The Changes of the Micro Structure by Deterioration Factors for LILW Waste Disposal Facility Concrete

2012 ◽  
Vol 482-484 ◽  
pp. 1664-1667
Author(s):  
Ki Beom Kim ◽  
Hae Ryong Jung ◽  
Ki Jung Kwon ◽  
Jang Hwa Lee ◽  
Do Gyeum Kim
Keyword(s):  
Physical Properties ◽  
Waste Disposal ◽  
Physicochemical Process ◽  
Sulfate Attack ◽  
Cement Matrix ◽  
Micro Structure ◽  
Freezing And Thawing ◽  
Concrete Deterioration ◽  
Disposal Facility ◽  
Deterioration Process

One of the most important deterioration mechanisms of concrete is that caused by the changes of the cement matrix. For this reason, the Freezing and Thawing and Sulfate attack of concrete has been considered for years a subject of interest in researches of cement chemistry. The concrete deterioration process is a complex physicochemical process that slowly modifies the structures of the concrete in the course of time and induces changes into its chemical and physical properties

scholarly journals Microscopic analyses of weathered granite in ion-adsorption rare earth deposit of Jianxi Province, China

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroki Mukai ◽  
Yoshiaki Kon ◽  
Kenzo Sanematsu ◽  
Yoshio Takahashi ◽  
Motoo Ito
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Inductively Coupled Plasma ◽  
Sulfate Solution ◽  
Jiangxi Province ◽  
Ion Adsorption ◽  
Inductively Coupled ◽  
Weathered Granite ◽  
Inner Sphere ◽  
Scanning Transmission

AbstractWeathered granite of ion-adsorption rare earth elements (REEs) ore collected at Jiangxi Province, China was investigated to identify the minerals abundant in REEs. The analyses of scanning electron microscopy (SEM)-energy dispersive spectrometry (EDS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for individual mineral particles of the weathered granite showed that kaolinitic particles formed by K-feldspar weathering contained large amounts of REEs. Scanning transmission electron microscopy (STEM)-EDS analyses revealed that the kaolinitic particles were mainly composed of kaolinite, illite and hematite. The elemental maps by Nano-SIMS for the kaolinitic particle clarified that La and Y are particularly concentrated in illite. The presence of illite presumably contributes to the formation of the REE accumulation zone in weathered granite. Furthermore, in the in-situ desorption experiment, nearly half the REEs (45.5%) remained in the kaolinitic particle after the treatment with 0.5 M ammonium sulfate solution. The desorption ratio of heavy REEs (HREEs: Gd–Lu) (60.4%) was lower than that of light REEs (LREEs: La–Eu) apart from Ce (69.0%). These results suggest that REEs form inner-sphere complexes on the kaolinitic particle. It can be assumed that the inner-sphere complexation suppresses the extraction ratio of REEs from the ores by ion-exchange treatment.

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