A Distributed Simulation Framework Using HLA for Circular Economy Modeling in Road Construction

Road construction consumes large quantities of virgin aggregates and asphalt, while circular-economy (CE) strategies, such as using reclaimed asphalt pavement (RAP) and recycled aggregates, remain underutilized due to quality uncertainties, logistical constraints, and limited digital integration.Existing simulation tools are predominantly linear and single-site, which prevents the realistic evaluation of CE strategies across demolition (DEM), mixing (MIX), and construction (CON) operations.This paper introduces a distributed simulation framework based on the High-Level Architecture (HLA) that links DEM, MIX, and CON federates to model dynamic, multi-site and closed-loop material flows.A conceptual CE framework, a set of simulation requirements, and a literature-based gap analysis are developed.A proofof-concept implementation demonstrates federate connectivity and quantifies CE effects: recycled flows supply 544 t of RAP and 7,500 t of mineral recyclates, reducing virgin-material demand by roughly 25 %.The results demonstrate that distributed simulation offers a feasible and extensible framework for analyzing CE strategies under realistic operational constraints, thereby supporting sustainable, smart, and lean road-construction planning through network-level logistics, environmental indicators, and scenario-based optimization.