Determination of correlation of compressive strength with maturity of concrete mixed with accelerator

Abstract

The compressive strength of concrete mixtures with accelerator additives designed for structural elements with strength of 5000 psi was correlated with the maturity index of concrete at an early age. The design of the mixture was made by adding the quantity of additives according to the specifications of the supplier. The maturity index was calculated using the thermal profile of the concrete dependent of the setting time, which was obtained through an automated adiabatic system. The number of thermal sensors required for temperature measurement dependent of setting time (1, 3, 7, 14 and 28 days) was determined by a factorial experimental design of two factors. The correlation coefficient was 0.96, so the logarithmic model adequately explains the variability of the compressive strength. The equation obtained was validated by means of the values of resistance to compression measured by the standard method for each age of the concrete; all values are within the calibration range of the resistances estimated by the maturity method.