Color stability in mortars and concretes. Part 2: Study on architectural concretes

• The color stability in architectural concretes was studied.
• Color was characterized using the CIELAB color space.
• Results from CIEDE1976 and CIEDE2000 color-difference formulas were compared.
• The weathering effect on the concretes color was analyzed.
• Concretes with iron oxides lost the color but retained the hue.

The aim of the present study was determining the color stability levels in architectural concretes. The color was defined using the CIELAB space proposed by the Commission Internationale de l’Eclairage (CIE), while the color stability was evaluated comparing the results coming from the CIEDE1976 and CIEDE2000 color-difference formulas. The color of samples exposed to different environments as well as the color-difference among the different instances of measurement are reported. The studied material was white and grey cement colored with iron oxides or phthalocyanines pigments. Results revealed loss of color in natural environment, important changes when phthalocyanines were used, and better color stability in the Colored Self-Compacting Concrete with iron oxides pigments.