Compressive Strength of Rock‐Filled and Conventional Concretes Across Curing Conditions and Aggregate Scales

ABSTRACT

Rock‐filled concrete (RFC) reduces cement consumption by incorporating preplaced large rocks within a self‐compacting cementitious matrix. However, limited evidence is available on how its compressive‐strength development responds to curing deficiencies across different matrix‐strength levels, particularly compared with conventional concrete systems. This study investigated RFC, conventional vibrated concrete (CVC), and self‐compacting concrete (SCC) with C15 and C30 strength grades. Specimens were subjected to standard water curing or outdoor exposure without additional moisture curing and tested after 1, 7, and 28 days. RFC achieved the highest 28‐day compressive strengths, reaching 28.66 MPa for C15 and 36.85 MPa for C30 under standard curing. RFC‐C15 exhibited only a 14.2% strength reduction at 1 day under inadequate curing, whereas its reduction increased to 31.6% at 28 days, demonstrating the increasing dependence of rock‐skeleton contribution on matrix hydration. Five machine‐learning models were evaluated for strength prediction. Within the investigated dataset, XGBoost produced the lowest prediction errors, with R ²  = 0.9633, RMSE = 1.99 MPa, and MAE = 1.36 MPa. Because aggregate scale was inherent to each concrete system, the observed differences represent combined system‐level effects rather than an independently isolated aggregate‐size effect. These findings clarify the curing‐dependent strength development of RFC and establish a basis for data‐assisted strength assessment within the investigated material domain.