CONCRETE STRENGTH ESTIMATION AT EARLY AGES: MODIFICATION OF THE METHOD OF EQUIVALENT AGE

This paper discusses the estimation, at early ages, of the compressive strength of a concrete mix subjected to a temperature history. The method of "equivalent age" based on the Arrhenius law is used. It involves a new definition of the rate of hydration linked to the concrete strength. This rate of hydration includes a model of a linear decrease of the long-term strength of concrete with increasing temperature. Tests at constant and variable temperatures were carried out. They enable, first, the proposed method applicable to the problem to be verified, and second, the accuracy of the new approach to be compared with that of the one currently used on construction sites.