Experimental Characterization and Numerical Performance Assessment of Treated Cinder Gravel for Base Course Applications

This study investigated the suitability of natural cinder gravel blended with fine‐crushed aggregates as a base course pavement material using laboratory tests and numerical simulations. Laboratory test results for natural cinder gravel indicated that cinder gravel alone failed to meet the Ethiopian Roads Authority (ERA) standard specifications for some tests, and they showed marginal quality values to the standard specifications for GB2 and GB3 base course materials. Thus, mechanical stabilization was performed at different percentages of finely crushed rock (0%, 15%, 20%, 25%, and 30%) by the dry weight of cinder gravel to improve its mechanical and physical properties A blend of 75% cinder gravel with 25% CFA resulted in Los Angeles abrasion (LAA), SG, aggregate crushing value (ACV), aggregate impact value (AIV), plastic index, water absorption, and CBR of 35.7%, 2.7%, 28.1%, 27.98%, nonplastic (NP), 1.16%, and 125%, respectively, fulfilling the required ERA standard specifications of GB2 and GB3 materials. The numerical simulation conducted using PLAXIS 3D demonstrated that the treated cinder gravel base course layer exhibits reduced vertical deformation, higher stiffness response, enhanced ability to dissipate stresses laterally, reducing excessive strain concentrations, and better load‐carrying capacity under standard traffic loading. These findings assure the potential use of treated cinder gravel as a sustainable and cost‐effective base course material alternative to conventional crushed stone aggregates. Therefore, the use of 75% cinder gravel by weight is recommended for the road base course layer as an alternative material in places where the materials are abundantly available.