MULTI-EXPONENTIAL MODELS AS DESCRIPTIVE TOOLS FOR PLAIN CONCRETE AND FRC

ABSTRACT The paper reports on descriptive tools developed for modelling the response of plain concrete and fibre reinforced concrete (FRC) under various types of loadings. Double and four-exponential models have been developed for use with plain concrete and FRC respectively. The first part of the paper deals with the double-exponential (double-e) model. Three shape parameters are required to fully define the strain-softening response typical of that for plain concrete. Each parameter has a different effect on the ultimate curve shape. An objective method of evaluating the shape parameters, which adds to the attractiveness of the model, is shown. The second part gives details of the four-exponential (four-e) model, which requires six shape parameters. This model was developed specifically to describe the more complex load-deformation response displayed by FRC. Similarly, an objective procedure has been developed for deriving the necessary shape parameters. Comparisons between experimental results and the descriptive models demonstrate the wide applicability of the multi-exponential models.