Effects of Strength and Age on Stress-Strain Curves of Concrete Specimens

Abstract

Many researchers have rigorously studied the nonlinear behavior of the stress–strain relationship of concrete using mathematical curves.Currently, most empirical expressions for the stress–strain relationship, however, have been focused on hardened concrete and are unable tocompletely represent the behavior of concrete at an early age. A broad understanding of the behavior of concrete from early age to old age isimportant in evaluating the durability and service life of concrete structures.In this paper, the effect of five different strength levels and various ages from 12 h to 28 days on the compressive stress–strain curve wasobserved experimentally and analytically. Tests were carried out on ; 100200 mm cylindrical specimens cured in a standard moist room ata temperature of 20 ± 3 C. An analytical expression of the stress–strain curve with strength and age was developed using regression analyseson experimental results. For verification of the proposed model equation, the equation was compared to the experimental data and existingmodel equations.The result shows that the proposed model equation is not only compatible with the experimental data but also describes satisfactorily theeffect of strength and age on the stress–strain curve.