The components of strain in concrete under sustained compressive stress

Abstract

Summary The strain of concrete under sustained compressive stress is examined in terms of three components, instantaneous recoverable, time-dependent recoverable and irrecoverable, defined here as elastic, delayed elastic and flow respectively. Experimental evidence is presented of the influence on each of the length of the period of loading and the age of the concrete when the load is applied. It was found that at a given age the rate of flow is virtually independent of any earlier loading and that the delayed elastic strain tends to a limiting value which varies little with the age of the concrete. The rate of occurrence of delayed elastic strain diminishes with the age of the concrete and it can be linked with the corresponding rate of flow.