The most aggressive ions in sea water for cement concrete
Dear Dr. Saleh
You may refer to this useful paper
Article Strength and microstructure analysis of concrete containing ...
Dear Saleh, you may need to read the article:
"Effects of Sea Water on Concrete" By Bryant Mather.
Best wishes.
The chemical attack of seawater on cement constituents is the reactions between sulphates, as well as chlorides, which are the most aggressive ions with cement constituents, because certain constituents of cement can enter into deleterious reactions with SO42- and Cl-, leading to the dissolution of Ca(OH)2 and the formation of sulphoaluminate and chloroaluminate hydrates, which cause expansion and softening of concrete, respectively. The CaCl2 that is formed from the reaction of MgCl2 with liberated lime increases the solubility of Ca(OH)2 that permits leaching. Thus, Mg(OH)2 dissociates C-S-H and
produces Ca(OH)2 and silica gel
Dear Dr. Mohannad Husain Al-Sherrawi
Yes, the article entitled "Effects of Sea Water on Concrete" By Bryant Mather. is very useful
All the best Regards Sincerely Yours, Prof. Dr. Saleh Abd El-Aleem Mohammed (Applied and Engineering Inorganic Chemistry) Vice-Dean Faculty of Science, Fayoum University, Fayoum, Egypt [email protected]
A lot of concrete degradation is reported in marine environments due to detrimental ion diffusion in seawater. Marine environments have significant concentrations of chloride and sulfate ions that count as a detrimental factor for the long-term durability of concrete. Chloride and sulfate ions affect the durability of the steel reinforcement and concrete, respectively. Moreover, subjecting reinforced concrete to the tidal zone may intensify this deterioration due to frequent drying–wetting cycles.
Chloride ions are the most important factor in the corrosion of reinforced concrete. The chloride concentration around the steel bars determines the possibility of corrosion and penetration. One of the products of chloride attack is chemical binding between chlorides and C3A that yields Friedel’s salt (3CaO·Al2O3·CaCl2·10H2O)
Another threat in marine environments is the penetration of sulfate ions through diffusion and capillary suction. Some common forms of sulfate ions found in seawater, such as Na2SO4 and MgSO4, result in the expansion of the concrete samples and reduction of compressive strength.
Calcium sulfate is the main product of the sulfate ions’ reaction with the lime in the hydration process, which is followed by the formation of thaumasite (CaSiO3⋅CaCO3⋅CaSO4⋅15H2O) at low temperatures. Ettringite (3CaO·Al2O3·3CaSO4·32H2O) and gypsum (CaSO4⋅2H2O) are produced by calcium sulfate reactions with C3A and these lower concrete performance by causing the concrete to expand and crack.
Dear Dr. Saleh
You may refer to this useful paper
Article Strength and microstructure analysis of concrete containing ...
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