Volume 4, Issue 8 (September 2007)
Effect of Material Parameters on Color of Cementitious Pastes
When matching in-situ concrete, such as for repairing or rehabilitating a structure, consideration must be given to its color. Matching the color can often be difficult and subjective. The aim of this study was to focus on the cement paste color component of concrete by performing laboratory experiments on hydrated paste samples to determine how various parameters affect the color. The two main categories investigated were: (1) materials and proportions, and (2) curing conditions. The lightness, hue, and saturation color values were measured using a colorimeter that gave L*a*b* numerical values. Cement powder color had the greatest effect on cement paste color. Other parameters that greatly affected the paste color were water-cement ratio, mineral admixtures, and hydration age for young pastes (less than 14 days). Parameters that showed very little effect were chemical admixtures and entrained air.