In this paper, equivalent age method and maturity method based on the temperature history of concrete were examined as strength estimation method for removal of sheathing. In strength development of two methods, it is relatively consistent in ordinary Portland cement, high-early-strength Portland cement. But there was a tendency that the difference was large in Portland blast-furnace slag cement (BB), Portland fly-ash cement (FB). Under the conditions of this report, the applicability of maturity method for FB was confirmed, but in application to estimating strength, it is necessary to consider the influence of kind of admixture and substitution rate.