Effects of the aggregate size and specimen dimensions on the brittle fracture of concrete

There is a large argument about the reported findings in literature with respect the effect of the concrete-specimen size and maximum aggregate size on the fracture properties of concrete. This argument was the direct motivation for the National Science Foundation (NSF) to initiate a research program objecting at providing a reasonable understanding of the effects of the specimen size and aggregate size on the fracture properties of concrete. The authors have conducted an extensive experimental program over the past 15 years and published a series of novel papers that discussed their results and compared them with results of other reliable studies. Herein, the authors summarize major findings and clarify critical factors, with a dominant goal of making valuable information available for interested researchers. The relationships between the size effects and main fracture parameters such as crack length and trajectories, critical energy release rate, and fracture roughness and toughness were explored.