Tiny amounts are used. Latex additive is sometimes used in concrete, adding it to the water first. Pigments or dyes can be added to the mix, or applied to the surface of set concrete. Special dyes are made for this purpose as common pigments can be broken down by the alkalinity of the cement. Blues and greens are available but costly for large projects.
Pigments are available as liquids, or as powders.
Concrete can also be surface coloured with acid stains or opaque stains made for outdoor use. The latter has a wide range of colours, but some may not be long-lasting. In some circumstances it is advisable to seal the concrete surface to reduce water penetration, which aids frost resistance and resists acid rain. Most of the readily available sealers are acrylic-based. Some may affect the surface finish leaving it glossy and they may yellow slightly over time, and need renewing if used outside.