Roller-Compacted Concrete Volumetric Mix Design Framework for Constructability and Sustainability

Abstract: Current roller-compacted concrete (RCC) pavement mix design procedures do not directly account for aggregate sources and rely on the designer’s experience to iteratively meet fresh and hardened performance targets at a fixed cement content. Standard test methods such as the modified proctor, Vebe apparatus, and vibratory hammer are currently used to determine final mixture proportions, evaluate consistency, and prepare cylindrical specimens for strength but do not replicate the mode and levels of compaction observed in the field. The inability to reliably evaluate RCC constructability in the laboratory forces contractors to resort to costly field test strips. For this study, a laboratory testing protocol was developed using a gyratory compactor and RCC volumetrics to evaluate RCC constructability (paveability, compactability, and stability). A testing plan was designed to evaluate multiple RCC mixtures with distinct aggregate morphologies, paste contents, paste rheology, and binder composition to connect material selection to constructability. Field RCC projects were visited to calibrate laboratory performance with field constructability and establish universal RCC volumetric parameters such as intergranular voids (IGV), total paste volume (TPV), ratio of voids filled by paste (VFP), effective paste film thickness (EPFT), and water-to-cement ratio (W/C). This study combines the advances into a mechanistic-based mix design framework using laboratory and field-calibrated mixture volumetrics that targets RCC constructability and sustainability. The proposed framework selects constituents and aggregate proportions, recommends initial mix proportions using volumetrics, proposes a methodology to quantify constructability with a gyratory compactor, and suggests adjustments for underperforming mixtures or sustainability targets.