To the Question of Structure Formation of Dispersed Systems in Cement Technology
Chernyak Lev,
Sviderskyy Valentin,
Tokarchuk Volodymyr,
Dorogan Natalia
Issue:
Volume 5, Issue 3, September 2020
Pages:
41-46
Received:
10 July 2020
Accepted:
24 July 2020
Published:
10 August 2020
Abstract: In the this publication, readers will find the results of the analytical and experimental research into the physical and chemical processes in the consecutive formation of structures at the major technological stages of the present-day production of portland cement. Dispersed systems of raw mixtures, which in different methods of production are formed at the stage of grinding, mixing and homogenization of raw materials, belong to different classification groups. In wet and combined methods is produced cement sludge - aqueous dispersed system, which belongs to the 2nd group: two-phase systems such as solid dispersed phase - liquid dispersion medium. In the dry method dispersed system is formed, which belongs to the 3rd group: three-phase systems such as solid dispersed phase - water-liquid and air-gas dispersion medium. The structural-mechanical and rheological properties of the coagulation structure of cement slurries, wich differ in the main raw material components, are shown. The study of deformation processes of aqueous dispersed systems showed that the nature of the development of deformations - rapid elastic ε0’, slow elastic ε2’ and plastic ε1’τ sludge samples belong to different structural - mechanical types. At the same time differences in quantitative values and a ratio of the specified types of deformation are noted. Readers will also find the particularities of the phase changes in the process of the crystallization structure formation at baking to maximum temperature 1450°С.
Abstract: In the this publication, readers will find the results of the analytical and experimental research into the physical and chemical processes in the consecutive formation of structures at the major technological stages of the present-day production of portland cement. Dispersed systems of raw mixtures, which in different methods of production are for...
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A Classification Approach for Corrosion Rating of Soil to Buried Water Pipelines: A Case Study in Budhanilkantha-Maharajganj Roadway Areas of Nepal
Abiral Poudel,
Kumar Prasad Dahal,
Dinesh K. C.,
Jagadeesh Bhattarai
Issue:
Volume 5, Issue 3, September 2020
Pages:
47-56
Received:
13 August 2020
Accepted:
24 August 2020
Published:
22 October 2020
Abstract: The present study was focused to estimate six characteristics of soil specimens taken from 0.3 to 1.5 m sampling depth of six sampling sites of Budhanilkantha-Maharajganj roadsides using standard methods, and was assessed their corrosive nature to the buried-metallic pipelines using an empirical corrosion rating model. The estimated soil pH, moisture, resistivity, redox potential (ORP), chloride and sulfate ions were 6.4-7.9, 7-45%, 4.5 × 103-45.5 × 103 Ohm. cm, 317-514 mV (SHE), 12-86 ppm, and 40-294 ppm, respectively, in all the soil sample specimens. The experimental results indicated that the soils could be rated as mildly corrosive to less corrosive groups to the buried galvanized-steel and cast iron pipes in the study areas. A good positive or negative correlation coefficient between resistivity, moisture, chloride and sulfate contents implies that these soil parameters have an equal contribution to the rating of soil corrosivity. A polyethylene-sheet wrapping (i.e., encasement) around the galvanized-steel and cast iron water pipelines or the use of non-conducting materials of gravel/sand around the burying ground could be sufficient for the extension of their life up to 50 years or more. The empirical model is successfully applied for the corrosion rating of soil samples and could be progressive in the future for soil corrosion rating of soils to the underground waterworks. Present findings would be insightful and suggestive in making the corrosive land maps of the studied areas which would be helpful for the potable water pipeline works in other urban areas of Nepal.
Abstract: The present study was focused to estimate six characteristics of soil specimens taken from 0.3 to 1.5 m sampling depth of six sampling sites of Budhanilkantha-Maharajganj roadsides using standard methods, and was assessed their corrosive nature to the buried-metallic pipelines using an empirical corrosion rating model. The estimated soil pH, moistu...
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