Effect of early age loading on concrete

Abstract

Early age loading of concrete is a common occurrence that affects the general integrity of the material in a structure. Such loading, however, should not be solely understood as the physical loading on concrete. Early age loading may be the result of, for example, early removal of formwork that may bring about inadequate curing methods. This loading is particularly important in todays construction practices since most buildings are required to be erected in the shortest time possible. If concrete is loaded within the crucial initial hydration period, secondary effects may be brought about which may be detrimental to concrete mechanical properties. A discussion of the effects of different loading ages is undertaken in this dissertation. It investigates the fact that when concrete is loaded at a later age, mechanical properties are still affected, but to a lesser extent than when loaded at earlier ages. The phenomenon of creep depends on various factors and is greatly affected when stress is induced during the initial phases of strength development. This dissertation presents an investigation of the mechanical properties of concrete at early ages, concrete deformations due to loading, and how concrete is affected both as a material and when forming part of a structure when such loading is applied at the initial stages after casting. An experimental investigation of such effects was also carried out and subsequent results analysed.