Improved compressive fracture models for self-consolidating concrete (SCC)

• There is a clear size effect for the compressive strength of SCC.
• Regardless of the (w/c) ratio, all cylinders broke by a diagonal fracture plane.
• The crack band zone become more localized with an increase of the (w/c) ratio.
• The transition size increases with an increase of the (w/c) ratio.
• SEL, MSEL, MFSL, and Sim et al.’s model captured the compressive size effect well.

This paper investigates the size effect phenomena in compressive strength of self-consolidating concrete (SCC) with different water to cement ratios, and attempts to model the experimental data coming from a series of laboratory unconfined compression tests. To this aim, several concrete cylinders having a constant slenderness ratio of two and diameters ranging from 50 mm to 200 mm were prepared, and tested under uniaxial compression. In addition, four theoretical models (i.e. size effect law (SEL), modified size effect law (MSEL), Sim et al.’s model, and multifractal scaling law (MFSL)) were investigated on their ability to catch this size effect by regression analysis using the nonlinear least squares method. The experiments indicated a pronounced strength reduction as the specimen size increases. The comparison of the goodness of fit between the models was quantified by using correlation coefficient R which provides that the models can interpret satisfactory the observed size effect.