Colouring additive for cement. Iron oxide pigment becomes firmly integrated in the cement and is weather resistant, alkaline resistant, ecologically benign and economical to use. The base mix design for all samples is 3:1 Sand and Cement (by weight). Oxide colour dosage is 5% by weight of Cement only, not total aggregate. Cements used are Blue Circle Builders Cement and Blue Circle Off White Cement. A fine sand was also used. Note, to lighten shown oxide colours, decrease the % of oxide and to darken, increase the % of oxide to a maximum of 10% to weight of cement. Adding more than 10% by weight will not intensify the colour. Colours shown are only to be used as an indicator; we suggest that individual trials are conducted prior to any major work being commenced. These oxide colours are available in Handy pack sizes or larger bags. For more information on oxidecolours, download our colour card.