A Methodology for Aggregate System Optimization Based on a Paste–Aggregate Binary Model

This research develops a mix design method for aggregates based on concrete workability, building upon the binary system model of paste and aggregate. The calculation model for aggregate packing density was refined by excluding particles smaller than 75μm and considering the inter-particle interactions among multiple aggregate size fractions. A method for calculating the specific surface area of the aggregate system, accounting for the particle size distribution within individual fractions and particle morphology based on the Cowley model, was established. This study proposes that the inter-particle spacing of aggregates is a crucial parameter for ensuring concrete workability. Consequently, an optimized aggregate proportioning method is presented, aiming to minimize paste volume while maintaining a fixed paste layer thickness around the aggregates.