Discrete element simulation of layered permeable structure design and anti‐blocking performance

Abstract This study investigates the clogging behavior of single‐ and double‐layer permeable concrete through laboratory experiments combined with computational fluid dynamics (CFD)–discrete element method (DEM) numerical simulations. Orthogonal experiments optimized the mix design, yielding a water–cement ratio of 0.31, silica fume content of 9%, and superplasticizer dosage of 1.05%. Two aggregate sizes were selected: 2.36–4.75 mm for the upper layer and 4.75–9.5 mm for the lower layer, forming a dual‐layer structure that satisfies road performance requirements. Clogging tests using six particle sizes and seven thickness ratios revealed distinct clogging patterns. Coarse particles (≥1.18 mm) accumulated mainly at the surface, medium particles (0.3–1.18 mm) blocked the 0–30 mm depth causing the greatest permeability loss, while fine particles (≤0.3 mm) penetrated the entire specimen. The 2:8 thickness ratio provided the best anti‐clogging performance: after five cycles, permeability decay rates for the three dominant particle sizes were only 11.83%, 34.56%, and 22.83%. CFD–DEM simulations closely matched experimental results (errors <10%) and revealed internal clogging mechanisms, with coarse particles retained within the upper 20 mm and fine particles more evenly distributed or flushed out. Overall, dual‐layer permeable concrete, particularly with a 2:8 ratio, effectively mitigates clogging, balances mechanical durability with sustainable permeability, and demonstrates strong potential for road engineering applications.