Analysis and modeling of the clean creep of concrete

Abstract

Basic creep of concrete is the part of the delayed deformationthat occurs when concrete is loaded without drying. In this workresults from the literature are analysed: the derivative of thecompliance function J of basic creep tests with different loadingages t0 are compared. It has been observed that consideringdJ/dt as a function of time t the long term behaviour is alogarithmic one with the same slope. Here it is shown that if weconsider dJ/dt as a function of the age since loading (t-t0) aunique behaviour is observed. This indicates that basic creepcould be expressed as a logarithmic function in which the age ofloading affects only the term (t-t0). In the recent Model Code2010 basic creep is exactly expressed like that. Using theexperimental data the parameters of the model are calculated foreach test and compared with the values proposed by MC2010. Itis shown that MC2010 gives a rather good set of values for thetwo parameters but it could be improved by adjusting someparameters on experimental results.