Color stability in mortars and concretes. Part 1: Study on architectural mortars

• The color stability in architectural mortars was studied.
• Color was characterized using the CIELAB color space.
• Results from CIEDE1976 and CIEDE2000 color-difference formulas were compared.
• The weathering effect was analyzed on the colored mortars.
• Loss of initial color was a function of the exposure conditions.

Architectural mortars are mixtures used in the building industry when aesthetic surface value is required. Cementitious mixtures with colorant agent, meet this requirement but color stability is not easy to ensure. This study determines the levels of color stability in architectural mortars. The main materials studied were grey cement and yellow iron oxide pigment. The CIELAB color space was adopted to define color and the CIEDE1976 color-difference formula was compared to CIEDE2000 to asses color stability. Results revealed loss of color in natural environments in a short time and excellent color stability in a chamber operating under controlled humidity and temperature conditions.