Shear Behavior of SCC Beams with Different Coarse-to-Fine Aggregate Ratios and Coarse Aggregate Types

The effect of mixture composition and coarse aggregate density on the shear strength and cracking behavior of self-consolidating concrete (SCC) beams are presented in this study. The experimental test parameters included coarse/fine (C/F) aggregate ratio (ranging from 0.7 to 1.2), coarse aggregate size (10 and 20 mm), coarse aggregate type/density (slag, expanded slate, and crushed stone), and varying compressive strengths (26-72 MPa). The density of the tested mixtures varied from 1,848 to 2,286 kg/m(3). The study investigates the fresh properties of all tested mixtures and the shear strength and cracking behavior of 16 full-scale concrete beams. Based on some selected design codes, the ultimate shear strength of the tested beams is also predicted. The results showed that SCC mixtures with a higher C/F ratio or bigger normal-weight aggregate had better flowability and less high range water reducer admixtures (HRWRA) demand. Although all tested beams showed comparable normalized shear strength, beams with a high C/F ratio or bigger normal-weight aggregate had higher postdiagonal cracking resistance. The results also showed that the expanded slate and slag lightweight aggregates were found to be relatively strong (compared to most common lightweight aggregates) as they did not entirely break along the diagonal crack. Increasing the volume of these lightweight aggregates in SCC mixtures not only reduced the mixture density but also enhanced the postdiagonal cracking resistance. (C) 2015 American Society of Civil Engineers.