ESTIMATION THE 7 AND 28- DAY NORMAL COMPRESSIVE STRENGTH BY ACCELERATED TEST METHODS IN CONCRETE

Abstract

Curing of concrete is the maintenance of a satisfactory moisture content and temperature for aperiod of time immediately following placing so the desired properties are developed. Acceleratedcuring is advantages where early strength gain in concrete is important. The expose of concretespecimens to the accelerated curing conditions which permit the specimens to develop a significantportion of their ultimate strength within a period of time (1-2 days), depends on the method of thecuring cycle.Three accelerated curing test methods are adopted in this study. These are warm water,autogenous and proposed test methods. The results of this study has shown good correlationbetween the accelerated strength especially for the proposal curing test method and normal strengthusing normal curing method at ages 7 and 28 day for the five different chemical composition ofcement with different water to cement ratios equal to 0.45, 0.55, 0.65 and 0.75. Linear andnonlinear regression analysis show high correlation for the different types of the accelerated curingmethods with coefficient of correlation (R2) more than 0.9.