scholarly journals Effects of blended cements and carbonation on chloride-induced corrosion propagation

2021 ◽  
Vol 145 ◽  
pp. 106458
Author(s):  
Miha Hren ◽  
Violeta Bokan Bosiljkov ◽  
Andraž Legat
Keyword(s):  
Blended Cements ◽  
Corrosion Propagation ◽  
Chloride Induced Corrosion

Scanning Electron Microscopy and x-ray analysis of microparticles and early hydration effects

1995 ◽  
Vol 53 ◽  
pp. 692-693
Author(s):  
Yun Lu ◽  
David C. Joy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Morphological Development ◽  
Early Hydration ◽  
X Ray ◽  
Blended Cements ◽  
Powder Particles ◽  
Chemical Wastes ◽  
Scanning Electron

High resolution scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) were performed to investigate microparticles in blended cements and their hydration products containing sodium-rich chemical wastes. The physical appearance of powder particles and the morphological development at different hydration stages were characterized by using high resolution SEM Hitachi S-900 and by SEM S-800 with a EDX spectrometer. Microparticles were dispersed on the sample holder and glued by 1% palomino solution. Hydrated bulk samples were dehydrated by acetone and mounted on the holder by silver paste. Both fracture surfaces and flat cutting sections of hydrating samples were prepared and examined. Some specimens were coated with an 3 nm thick Au-Pd or Cr layer to provide good conducting surfaces. For high resolution SEM S-900 observations the accelerating voltage of electrons was 1-2 KeV to protect the electron charging. Microchemical analyses were carried out by S800/EDS equipped with a LINK detector of take-off angle =40°.

Utilization of petroleum sludge wastes for increasing productivity of ordinary portland cement

2021 ◽  
Vol 19 (4) ◽  
pp. 315-328
Author(s):  
N.M. Khalil ◽  
Yousif Algamal
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Production Capacity ◽  
Hydration Product ◽  
High Energy ◽  
Cement Industry ◽  
Blended Cements ◽  
Petroleum Waste ◽  
Waste Sludge ◽  
Suitable Amount

This work aims at maximum exploitation of petroleum waste sludge as additive to portland cement to prepare blended cements and hence increasing its production capacity without further firing. This will decrease the main cement industry problems involving environmental pollution such as releasing gases and high-energy consumption during industry and hence maximizes the production economics. Six batches of ordinary portland cement (OPC) mixed with different proportions of petroleum waste sludge (PWS) donated as C1 (control batch contains no PWS), C2 (contains 90 wt.% of OPC+10 wt.% of PWS), C3 (contains 80 wt.% of OPC+20 wt.% of PWS), C4 (contains 70 wt.% of OPC+30 wt.% of PWS), C4 (contains 60 wt.% of OPC+40 wt.% of PWS) and C6 (contains 50 wt.% of OPC+50 wt.% of PWS), were prepared and mixed individually with the suitable amount of mixing water. Cement mixes C2, C3 and C4 showed improved cementing and physicomechanical properties compared with pure cement (C1) with special concern of mix C4. Such improvement is due to the relatively higher surface area as well as the high content of kaolinite and quartz in the added PWS (high pozzalanity) favoring the hydration process evidenced by the increase in the cement hydration product (portlandite mineral (Ca (OH) 2).

scholarly journals Laboratory-scale study and semi-industrial validation of viability of inorganic CDW fine fractions as SCMs in blended cements

2021 ◽  
Vol 271 ◽  
pp. 121823
Author(s):  
J. Moreno-Juez ◽  
Iñigo J. Vegas ◽  
M. Frías Rojas ◽  
R. Vigil de la Villa ◽  
E. Guede-Vázquez
Keyword(s):  
Laboratory Scale ◽  
Blended Cements

Effectiveness of PCE superplasticizers in calcined clay blended cements

2021 ◽  
Vol 141 ◽  
pp. 106334
Author(s):  
Ran Li ◽  
Lei Lei ◽  
Tongbo Sui ◽  
Johann Plank
Keyword(s):  
Calcined Clay ◽  
Blended Cements

scholarly journals Layer-by-Layer Self-Assembly Composite Coatings for Improved Corrosion and Wear Resistance of Mg Alloy for Biomedical Applications

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 515
Author(s):  
Tongfang Liu ◽  
Song Rui ◽  
Sheng Li
Keyword(s):  
Wear Resistance ◽  
Self Assembly ◽  
Biomedical Applications ◽  
Composite Coatings ◽  
Covalent Bond ◽  
Mg Alloys ◽  
Mg Alloy ◽  
Layer By Layer ◽  
Corrosion Propagation ◽  
Chemical Linkage

Mg alloys are promising biomedical metal due to their natural degradability, good processability, and favorable mechanical properties. However, the poor corrosion resistance limits their further clinical applications. In this study, the combined strategies of surface chemical treatment and layer-by-layer self-assembly were used to prepare composite coatings on Mg alloys to improve the biocorrosion resistance. Specially, alkalized AZ91 Mg alloy generated chemical linkage with silane via Si–O–Mg covalent bond at the interface. Subsequently, Si–OH group from silane formed a crosslinked silane layer by Si–O–Si network. Further chemical assembly with graphene oxide (GO), lengthened the diffusion pathway of corrosive medium. The chemically assembled composite coatings could firmly bond to Mg alloy substrate, which persistently and effectively acted as compact barriers against corrosion propagation. Improved biocorrosion resistance of AZ91 Mg alloy with self-assembly composite coatings of silane/GO was subsequently confirmed by immersion tests. Besides, the Mg alloy exhibited good wear resistance due to outside layer of GO with a lubricant effect. Cell viability of higher than 75% had also been found for the alloy with self-assembly composite coatings, which showed good cytocompatibility.

scholarly journals Reinforced Concrete Bridge Deck Model Considering Delayed Exposure to Chlorides

2019 ◽  
Author(s):  
Petr Konečný ◽  
Petr Lehner ◽  
David Pustka
Keyword(s):  
Reinforced Concrete ◽  
Bridge Deck ◽  
Concrete Bridge ◽  
Reinforced Concrete Bridge ◽  
Corrosion Initiation ◽  
Chloride Induced Corrosion ◽  
Concrete Quality ◽  
Concrete Type ◽  
Concrete Bridge Deck ◽  
Delayed Exposure

The paper is focused on the model of the effect of delayed chloride exposure on the chloride induced corrosion initiation on ideal reinforced concrete bridge. The Finite Element-based numerical model is applied. The effect of concrete quality is expressed in the form of time dependent diffusion coefficient in order to evaluate the effect of concrete type as well as the effect of aging. The influence of extended chloride exposure on the corrosion initiation is introduced.

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