Parameter modification and extension of the compressible packing model (CPM) for steel fiber-aggregate mixtures

With the popularization of steel fiber reinforced concrete (SFRC), research on the packing of steel fiber-aggregate (F-A) mixtures has become a significant prerequisite for the mix design of SFRC. Although the compressible packing model (CPM) can be used to predict the packing density (PD) of F-A mixtures, its interaction coefficients are determined from the elementary particle classes without fibers (narrow particle size distribution), which limits the applicability of the CPM. In this study, after adding steel fibers to binary aggregate with wide particle size distribution, the PDs of steel fiber-binary aggregate (F-BA) mixtures were measured. The method of estab-lishing interaction coefficients for F-A mixtures was modified, and the general formulas of interaction coefficients were proposed. The novel CPM model after comprehensive corrections of fiber disturbance parameter and interaction coefficients for F-A mixture was established. Compared with the conventional CPM, the prediction accuracy of novel CPM was greater.