Effect of Specimen Size on the Compressive Behavior of Self-Consolidating Concrete Containing Polypropylene Fibers

In this study, the effect of specimen size on compressive strength of self-consolidating concrete (SCC) containing polypropylene (PP) fibers is experimentally examined. Six concrete mixtures with two strength levels (low and high strength) are proportioned. The specimens are geometrically similar, having circular cross sections of diameter 50, 100, 150, and 200 mm with a constant slenderness ratio of 2. Polypropylene fibers of two different lengths (6 and 12 mm) are added to SCC mixtures. As expected, an increase in specimen size leads to a reduction in strength for all specimens. However, the slope of reduction in strength decreases with the addition of PP fibers to concrete. Therefore the slope shows that the effect of increasing the specimen size diminishes after PP fibers are added to both low-strength and high-strength mixtures. In addition, three theoretical size effect models are assessed and new parameter values in the prediction models are proposed for SCC containing fibers. (C) 2017 American Society of Civil Engineers.