Cement concrete requires strength, durability, and workability. Furthermore, the appearance of concrete must be good. Recently, the concrete industry has a tendency to actively utilize byproducts, all over the world. But, consumers dislike the color of concrete using byproducts. This is an obstacle to the active use of byproducts. However, it is not clearly understood how consumers make the impression to color of concrete using byproducts. Therefore, we conducted a questionnaire survey using concrete using byproducts, and analyzed the answers with factor analysis and covariance analysis. As a result, the following was clarified: (1) three factors, such as beauty, massiveness and familiarity, were extracted as a factor of exposed concrete appearance, (2) the beauty of concrete was enhanced by the whiteness of the surface and was worsened by pits and surface yellowing, (3) the massiveness of concrete was worsened by the beauty and surface whiteness, and (4) even though the subjects knew that recycled byproducts were used in concrete, the evaluation of beauty did not change.
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