Cement pastes in tertiary colours: A digital approach for colouration of cement-based materials

Abstract

A tertiary colour design methodology based on the design of experiments (DoE) is introduced for cement paste in this paper. Different types and dosages of pigments are mixed into white cement to form tertiary colours. The quantitative correlation between the types and dosages of iron oxide pigments and the CIELAB parameters for coloured cement paste is established. The experimental results show that for the given ranges of pigment dosage: 0 ∼ 5% for white, red, yellow, blue, and green pigments and 0 ∼ 3.5% for black pigment, not just the white pigment but the black pigment also plays an important role in affecting the variations in the CIELAB parameters. The additions of red, yellow, green and blue pigments influence the green–red and blue-yellow opponent colours, and an interaction at high levels of addition for a pair of pigments is recognized. With the help of DoE, eight series of quadratic polynomial models were set up to correlate the CIELAB parameters obtained for coloured cement pastes with the pigment attributes. By using this method, tertiary colours can be introduced to cement-based materials that can satisfy the needs of various application scenarios.