Recently used white cement for marking out an excavation, and am wondering what the stuff is. Does anyone know what the chemical composition is? I did a google search but what comes up does not seem to be the same stuff you see in Thailand.
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Recently used white cement for marking out an excavation, and am wondering what the stuff is. Does anyone know what the chemical composition is? I did a google search but what comes up does not seem to be the same stuff you see in Thailand.
Maybe kaolin or chalk in it.
Is it a light cement (as in not heavy)?
White cement is a wet surfacing compound similar to plaster.
The characteristic greenish-gray to brown color of ordinary Portland cement derives from a number of transitional elements in its chemical composition. These are, in descending order of coloring effect, chromium, manganese, iron, copper, vanadium, nickel and titanium. The amount of these in white cement is minimized as far as possible. Cr2O3 is kept below 0.003%, Mn2O3 is kept below 0.03%, and Fe2O3 is kept below 0.35% in the clinker. The other elements are usually not a significant problem. Portland cement is usually made from cheap, quarried raw materials, and these usually contain substantial amounts of Cr, Mn and Fe. For example, limestones used in cement manufacture usually contain 0.3-1% Fe2O3, whereas levels below 0.1% are sought in limestones for white manufacture. Typical clays used in gray cement rawmix may contain 5-15% Fe2O3. Levels below 0.5% are desirable, and conventional clays are usually replaced with kaolin. Kaolin is fairly low in SiO2, and so a large amount of sand is usually also included in the mix. Iron and manganese usually occur together in nature, so that selection of low-iron materials usually ensures that manganese content is also low, but chromium can arise from other sources, notably from the wear of chrome steel grinding equipment during the production of rawmix. See rawmill. This wear is exacerbated by the high sand-content of the mix, which makes it extremely abrasive. Furthermore, to make a combinable rawmix, the sand must be ground to below 45 μm particle diameter. Often this is achieved by grinding the sand separately, using ceramic grinding media to reduce contamination.
White Portland cement - Wikipedia, the free encyclopedia
you can use white for a repair on existing concrete,Quote:
Originally Posted by thailazer
for some reason ,perhaps the heat created while it sets , concrete comes out light grey , if you try to repair a small area with grey cement/ sand mortar mix it looks too dark , hence adding some white cement to the mix to lighten it , so it blends in
for marking out ?
you could use it in the initial mix if you want a lighter face concrete , but its a lot 5 x ? more expensive and the mix would have to be measured correctly ,every time .
guess you could use anything highly visible ,especially if you're not the one paying for it