Mitigating arch expansion with skeleton dense structure in large-size cement-stabilised gravel mixes: experimental and DEM analysis

This study proposed large-size cement-stabilized gravel (LCSG) mixes as a preventive measure against arch expansion in semi-rigid base asphalt pavements. LCSG mixes with weak and strong skeleton dense structures (SDSs) were designed. Their mechanical and expansion properties under different cement contents were compared with conventional cement-stabilized gravel (CCSG) mixes. Thermal expansion of LCSG and CCSG mixes was further analyzed using the discrete element method (DEM). The results indicated that compared to CCSG mixes, LCSG mixes with a strong SDS and fewer fine aggregates reduced cement content by approximately 1.0%, exhibited a 23% lower compressive resilience modulus (CRM), and a 34.5% lower expansion coefficient. Mesoscopic simulations revealed that LCSG mixes had lower temperature gradients, vertical expansion, and reduced temperature stresses than CCSG mixes, demonstrating superior effectiveness in preventing arch expansion. These findings provide theoretical guidance for applying LCSG mixes in arid regions with significant temperature fluctuations.