Dynamic load effects on mechanical properties of recycled base pavement

The repeated and sustainable use of reclaimed road materials can greatly reduce environmental impact and resource waste, especially in rapidly developing infrastructure contexts. In this study, we tested the raw materials of a recycled base mixture – water, cement, reclaimed asphalt pavement (RAP), and reclaimed inorganic binder aggregate (RAI) – and optimised their proportions by way of screening and compaction experiments. We measured the compressive resilient modulus to parameterise a finite-element model in ABAQUS, which simulated how driving speed, axle load, and base-layer thickness influence crack propagation and stress behaviour under dynamic loading. Results show that higher RAI content raises the optimal moisture content, maximum dry density, and resilient modulus. Vehicle axle load strongly affects crack-tip stress intensity and vertical stress. Under high speeds, RAP:RAI ratios of 1:1 and 1:2 provide better performance, whereas a 1:4 ratio is preferable for lower-speed roads. With a 30 cm base layer, mixtures with 1:2 and 1:4 ratios demonstrate the greatest crack resistance. These findings support tailoring the mix ratio to practical road engineering conditions, offering quantitative guidance for design choices in recycled base layers.