Help with cement dyes
Help with cement dyes
(OP)
I'm a chemical engineer and don't know much about cement but I have been recruited to help some low income house builders in Tajikistan (rebuilding after a civil war) add dye to roofing tiles they make. Please read this description and and any help or suggestions would be appreciated.
We make what are called MCR tile Micro cement roofing tiles. Right now we are using a ratio of about forty percent cement and the rest sand and water. We mix this and place it on a vibration table. After it has been vibrated we place it on a plastic mold that gives it shape. There it rests for twenty four hours. We then demold it and place it in a water tank for five to eight days depending on the outside temperature. The tile then goes in a shed for a period of twenty four days, away from direct sunlight. It is then ready to be placed on a roof.
We bought some red cement from the factory but after the process and even during mixing of the cement it looked a dirty brown color. We have tried powder dyes that people add to paints but, the cement just eats the color as well.
Does anyone know what the best dyes for cement are? I just need someone to point me in the right direction. Thanks.
We make what are called MCR tile Micro cement roofing tiles. Right now we are using a ratio of about forty percent cement and the rest sand and water. We mix this and place it on a vibration table. After it has been vibrated we place it on a plastic mold that gives it shape. There it rests for twenty four hours. We then demold it and place it in a water tank for five to eight days depending on the outside temperature. The tile then goes in a shed for a period of twenty four days, away from direct sunlight. It is then ready to be placed on a roof.
We bought some red cement from the factory but after the process and even during mixing of the cement it looked a dirty brown color. We have tried powder dyes that people add to paints but, the cement just eats the color as well.
Does anyone know what the best dyes for cement are? I just need someone to point me in the right direction. Thanks.
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RE: Help with cement dyes
The correct pigment (not any dyes) is ironoxides.
In short view:
Ironoxides for red and yellow
cobaltoxides for blue
chromeoxides for green
you can use eihgter natural or synthetic oxides. according to reseaches the best results coming from synthetic ironoxides, becasue of stablity in the concrete alkali environmental.
As you remined that pigments are not reacts with concrete. These are inert and non-reactive, therefore the unique deformation is abration.
Synthetic oxides also not deformed by ultraviolet lights which coming from sun.
The correct percentage for coloured concrete is 2% or 3% of cement weight. you can use up to 6% maximum. But aware that pigments are imprurities for concrete, therefore, if you excess 6%, you will start to use strengh of concrete.
I hope these are usefull for you. If you want to discuss more merbas@garanti.net.tr
RE: Help with cement dyes
The correct pigment (not any dyes) is ironoxides.
In short view:
Ironoxides for red and yellow
cobaltoxides for blue
chromeoxides for green
you can use eihgter natural or synthetic oxides. according to reseaches the best results coming from synthetic ironoxides, becasue of stablity in the concrete alkali environmental.
As you remined that pigments are not reacts with concrete. These are inert and non-reactive, therefore the unique deformation is abration.
Synthetic oxides also not deformed by ultraviolet lights which coming from sun.
The correct percentage for coloured concrete is 2% or 3% of cement weight. you can use up to 6% maximum. But aware that pigments are imprurities for concrete, therefore, if you excess 6%, you will start to use strengh of concrete.
I hope these are usefull for you. If you want to discuss more merbas@garanti.net.tr
RE: Help with cement dyes
It is important to use finely ground oxides.
You can also get shades of grey to black by using carbon powder as a pigment, but be careful to keep the percentage low as it weakens the concrete.