抄録
Concrete hardening process under alternately changing temperature is studied in connection with a modified maturity theory proposed as eqs. (2) and (3). Fitness of this theory to the concrete hardening process under changing temperature depends largely upon the propriety of a hypothesis that maturity factor for concrete may accumulate regardless of the temperature variation in the curing period. This hypothesis is tested here by a large scale experiment designed to obtain much informations for the effects. Test conditions of curing temperature are determined to extract the character of atmospheric temperature variation that would be subjected to the concrete in practice in general. Programmed superposition of temperature variations having different periodic time will characterize this experiment. By applying the method of regression analysis to the test results, many factors concerning to temperature variation are proved to have no distinct effect on the hardening process of concrete defined as the development of mechanical properties of concrete, and accordingly, the modified maturity factor have a good correspondence to the process. The only exception is nothing but freezing and thawing of concrete, whose effect is verified to be significant by the result of variance analysis for the regression coefficients.
