Evaluation of Concrete Strength using Maturity Method

Abstract

The maturity method used for the estimation strength gain in concrete based on the measured temperature history during curing. This is a new technique to predict early ages concrete strength without crushing. The combined effects of ages, temperatures and water-cement ratio on strength gain are quantified by means of a maturity function.It is shown that the traditional Nurse-Saul maturity function is inferior compared with the function based on the Arrhenius equation.The concept of equivalent age is the most convenient measure of maturity. The gain of a specific concrete mixture is estimated using the measured maturity and the strength vs.maturity relationship for that mixture. It is shown that the maturity method can only be used reliably to estimate relative strength concrete.The present work is based on ASTM C 1074 which allows to estimate concrete strength at any given time using the structure’s unique temperature history.The purpose of this study was to analyze the effectiveness and accuracy of the maturity method to estimate concrete strengths for a variety of commonly used water-to-cement ratios (0.40 to 0.50). Strength gains only when temperature increases and water cement ratio decreases. Five sets of practical mix design based on IS 10262: 2009 was cured at an average temperature,and the same proportion of mortar was cured at five different constant temperatures of 10°C, 20°C, 30°C, 40°C,and 50°Cbased on ASTM C 1074. For each mix of concrete, cure twenty-one numbers of cylinders having dimension 150 x 300 mm. Fifteen numbers are using for compressive strength testing at 1d, 3d, 7d, 14d, and 28days and three cylinders are using to record the temperature history of the mix. In case of mortar, twenty-one numbers of cubes having dimensions (50 mm3) were used for compressive strength testing at 12 hours, 1d, 2d, 4d, 8d, 16d and 32 days. Compressive strength versus age data was examined. The limiting strength, cement reaction rate, datum temperature and activation energy have different water-cement ratio. The concept of equivalent age is the most convenient measure of maturity.