Help with cement dyes

[Sharon]

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.<br>
<br>
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.<br>
<br>
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. <br>
<br>
Does anyone know what the best dyes for cement are? I just need someone to point me in the right direction. Thanks.

 

[merbas]

Infact, all pigments are not for concrete. There are a lot of pigment existing.<br>
<br>
The correct pigment (not any dyes) is ironoxides.<br>
<br>
In short view:<br>
<br>
Ironoxides for red and yellow<br>
cobaltoxides for blue<br>
chromeoxides for green<br>
<br>
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.<br>
<br>
As you remined that pigments are not reacts with concrete. These are inert and non-reactive, therefore the unique deformation is abration.<br>
<br>
Synthetic oxides also not deformed by ultraviolet lights which coming from sun.<br>
<br>
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.<br>
<br>
I hope these are usefull for you. If you want to discuss more <A HREF="mailto:merbas@garanti.net.tr">merbas@garanti.net.tr</A><br>
<br>

 

[merbas]

Infact, all pigments are not for concrete. There are a lot of pigment existing.<br>
<br>
The correct pigment (not any dyes) is ironoxides.<br>
<br>
In short view:<br>
<br>
Ironoxides for red and yellow<br>
cobaltoxides for blue<br>
chromeoxides for green<br>
<br>
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.<br>
<br>
As you remined that pigments are not reacts with concrete. These are inert and non-reactive, therefore the unique deformation is abration.<br>
<br>
Synthetic oxides also not deformed by ultraviolet lights which coming from sun.<br>
<br>
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.<br>
<br>
I hope these are usefull for you. If you want to discuss more <A HREF="mailto:merbas@garanti.net.tr">merbas@garanti.net.tr</A><br>
<br>

 

[RiBeneke]

You can get ready-to-use pigments from some of the specialist companies that supply concrete additives .. I dont know the names in your area. Also chemical companies like Bayer make them.<br>
It is important to use finely ground oxides.<br>
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.