Concrete Carbonation is usually measured as discoloration, as it has one of strengths to be economical, and simple and immediately confirm the given results in the spot. And, when Carbonation is measured as Phenolphthalein Solution, it is possible to confirm the scope of alkali through acid and basic reaction. Then, Concrete Basic Reaction is decided according to alkali concentration depending on Potassium Hydroxide Now that Carbonation is gradually produced toward inner side from outer side, with time going by, it doesn’t work, to some adequate depth, in as fast time as compulsory facilitating test. Thus, this research thesis made a comparative analysis on concrete phenomenal discoloration borderline following Phenolphthalein Solution, as part of a bid to measure Carbonation. Also, the thesis measured 'Concrete Alkali Concentration. The result showed that concrete coloring is classified into red and scarlet according to alkali concentration, and into borderline breakpoint of the speckle of scarlet and carbonation reaction. The higher chroma becomes with concrete decolorizing, the higher alkali concentration becomes. Also, it was demonstrated that for long-term concrete discoloration borderline, discoloration degree can be determined by amounts of Potassium Hydroxide. Such result proved that limiting the extent of only red color as alkali, in the process of deciding on the scope of concrete alkali, can be served as an error in measuring service life of Concrete Carbonation.

To evaluate color change of concrete subjected to high temperature, we manufactured concrete samples and heated them to target temperatures of 100, 200, 300, 400, 500, 600, 700 and 800℃ in an electric oven and performed photo image analysis using photoshop computer software. The result of the study shows that color change using photo image analysis can be evaluated according to the different color coordinate.

Red mud is a waste generated by the aluminium industry, and its disposal is a major problem for this industry. Red mud has a reddish-brown color and superfine particle characteristics. So, it can be a promising pigment admixture for concrete industry. An experimental study was conducted to investigate the potential use of red mud in color concrete. The micro structures of red mud and iron oxide pigment such as porosity, pore size distribution, diameter of particle were analyzed with the aid of SEM, X-ray diffraction(XRD), and the infrared absorbance. Tests on physical properties of color concrete, such as strength, slump, early shrinkage crack patterns, and color characteristics were carried out and the results were reported in this paper.