The most common aggregate available for an upcoming job is a rather dark brown. Will this work against us in making white concrete? We could substitute another aggregate in whole or in part. Does the coarse aggregate affect the color more than the fine aggregate?
Dark aggregates are likely to show through the surface at those places where there is only a thin layer of cement paste over them. Sometimes these will mar the appearance of the concrete. Unwashed and contaminated aggregates should be particularly avoided. Fine aggregate has a stronger influence on the color of white concrete than does the coarse aggregate and, where desired, the color may be modified to some extent by the choice of the color of fine aggregate.