CONTINUOUS RETARDATION SPECTRUM FOR SOLIDIFICATION THEORY OF CONCRETECREEP

The basic creep of concrete is the time-dependent strain caused by a s ustained stress in absence of moisture movements. It is the strain obs erved on sealed specimens, Similar to other properties of concrete, it is dependent on the age of concrete, as a consequence of long-time ch emical reactions associated with the hydration of cement. This paper f ormulates the solidification theory with a continuous retardation spec trum, and shows how this spectrum can be readily and unambiguously ide ntified from arbitrary measured creep curves and how it then can be ea sily converted to a discrete spectrum for numerical purposes. The iden tification of the continuous spectrum is based on Tschoegl's work on v iscoelasticity of polymers. Attention is limited to basic creep.