Please advice on any reliable and preferably a simple technique for the synthesis of solution representing the pore solution of ordinary cement system.
The pore solution contains also other important ions besides Ca++, OH- and alkali, for example sulfate ions. A classic work on pore solution composition is Page, C. L., & Vennesland, Ø. (1983). Pore solution composition and chloride binding capacity of silica-fume cement pastes. Matériaux et Construction, 16(1), 19-25. Here you can find some typical compositions.
Other pore solution compositions can be found in work by Lothenbach and co-workers, for example: Lothenbach, B., & Winnefeld, F. (2006). Thermodynamic modelling of the hydration of Portland cement. Cement and Concrete Research, 36(2), 209-226.
The pore solution changes both with age, as cement hydrates, and with w/c, especially the alkali concentration. At early age, you can filter out the pore solution from a relatively high w/c paste, while at later ages you will need a special setup to press out the pore solution under a press. For low w/c, it is anyway difficult to obtain enough pore solution after a couple of days of hydration. I have some data on low w/c pastes that I can send to you if you wish.
Pay attention also that you need to protect the pore solution from CO2.
Hope this is of help.
Saturated Ca(OH)2 solution, with KOH and NaOH as required for your alkalinity
or
cement extract: add water to cement, mix, and take the liquid filtrate
An easy way to obtain a solution with similar properties and pH than concrete is to mix the paste you want to simulate and try to filter the water from that fresh paste.
Thank you Prof.X. Ramón Nóvoa & Ms.Susana for your inputs.
It would be very helpful, if you could you pls. elaborate on say, if I want to simulate the pore solution of a 0.4 water to cement ratio paste (cement+water), how do I go about it. Adding the cement and water would give me a paste from which it would be difficult to extract/filter out the water.
The pore solution is Ca(OH)2 saturated so no much importance what the w/c ratio is. You can take 1:1 ratio, overnight mix, and filter through a glass filter, for example.
The pore solution contains also other important ions besides Ca++, OH- and alkali, for example sulfate ions. A classic work on pore solution composition is Page, C. L., & Vennesland, Ø. (1983). Pore solution composition and chloride binding capacity of silica-fume cement pastes. Matériaux et Construction, 16(1), 19-25. Here you can find some typical compositions.
Other pore solution compositions can be found in work by Lothenbach and co-workers, for example: Lothenbach, B., & Winnefeld, F. (2006). Thermodynamic modelling of the hydration of Portland cement. Cement and Concrete Research, 36(2), 209-226.
The pore solution changes both with age, as cement hydrates, and with w/c, especially the alkali concentration. At early age, you can filter out the pore solution from a relatively high w/c paste, while at later ages you will need a special setup to press out the pore solution under a press. For low w/c, it is anyway difficult to obtain enough pore solution after a couple of days of hydration. I have some data on low w/c pastes that I can send to you if you wish.
Pay attention also that you need to protect the pore solution from CO2.
Hope this is of help.
Thank you Mr. Lura for your valuable advice. Yes I will like to have the data and it will be of immense help. I am messaging you mu email id. Thank you again for sharing your ideas.
Thanks a lot Pietro Lura, X. Ramón Nóvoa and Susana G. Sanfélix.
Thanks to Kaustav Sarkar for asking this question.
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