Part B Micro Color pigments must be treated and added to the mixer at a different point than regular pigments because pigment particle stacking (PPS) must be avoided. Just like sand, pigment can have many different gradations. Iron Oxides are quite coarse with a typical particle size of about one micron and a surface area of between five and ten square meters per gram. Or between 20,000 and 40,000 square feet per pound of pigment. This sounds like a lot until Part B Micro Colors are added to the mix.
Because Part B Micro Color pigments are smaller particles and have surface areas between 50 and 80 square meters per gram or over 200,000 square feet per pound, they must be added at a different point versus other pigments or PPS will occur. A smaller pigment particle cannot bond to a larger pigment particle. The reason for adding Part B Micro Color pigments to cement and concrete is to achieve darker, more saturated shades of cement and concrete.
These pigments should be added to the mixer ONLY after the cement has been fully wetted with all water and admixtures. In other words, towards the end of batching. In addition, as Part B Micro Color pigments are defined as high performance pigments, only Ultra High performance mix designs should be used; with water to cement ratio's below 0.34. If not, the surface tension of the water will not be reduced and the pigment will not disperse completely.
Clarke Part B pigments are extremely specialized and must be used according to procedure. The automotive industry including Rolls Royce, Mercedes, BMW, Ferrari and Cadillac all use Part B type pigments for their coating and paint systems.
See this example of a Part B pigment properly dispersed on the right and added incorrectly on the left. Note the dramatic differences in color.
Both these samples use exactly the same pigment - Micro Blue RS, and are made at exactly the same loading level of 0.30%. Same cement and sand with weights at identical ratios. Exactly the same curing times under identical temperature conditions. Exactly the same total mix times. But the pigments are added at different points during sequencing.
Both batches use the same water, however not at the same water to cement ratio: 0.45 vs 0.32. Part B pigments must be added towards the end of sequencing after the cement is fully wetted. Mix designs with excess water at cement ratios above 0.36 cannot use Part B pigments due to the surface tension of the excess water. High Performance Concrete HPC and Ultra High Performance Concrete UHPC that use proper admixture technology are required for Part B pigments.
Part B Micro Color Pigments:
Micro Blue RS: An extreme Red Shade high performance Blue particle. Can be added to all Macro and Custom pigments but used specifically to enhance high loading Cobalt Blue 11L636, 11L747 and Cinder. Loadings from 0.01-0.50%. For maximized high chroma colors, can be taken up to a 1.00% loading in specific formulas.
Micro Blue GS: An extreme Green Shade high performance Blue particle. Can be added to all Macro and Custom pigments but used specifically to enhance high loading Cobalt Teal 535, Cobalt Aqua 11L848 and Spruce. Loadings from 0.01-0.50%. For maximized high chroma colors, can be taken up to a 1.00% loading in specific formulas.
Micro Red: A high performance Bright Red particle. For Stop sign and Fire Engine/Ferrari red, combine with a high loading of BRICK. Loadings from 0.01-1.00%.
Micro Green: A high performance Copper Phthalocyanine Green particle. Can be added to Cobalt Teal 535, Aqua 11L848 and Spruce, as well as Cinder Black. Can also be added to Green 334 and various yellows at extremely low loading rates (below 0.05%) for specific NCS formula codes. Loadings from 0.01-1.00%.
Micro Yellow: A pigment to be used in white cement only. Extreme bright yellow shades can be achieved in combination with various other yellow pigments such as Yellow Oxide, Golden and Yellow 225. Must be Admixture Certified. Loadings from 0.01-0.50% Max.
Micro Magenta: A high performance Magenta/Burgundy particle. Can be used with all Macro and Custom pigments, but specifically designed to be used in combination with high loadings of Wine, Purple, Cobalt 11L747, Cinder, Brown and Micro Red. Loadings from 0.01-0.50%.