Identifying Practical Screening Indicators for Quarry Pond Fines in Cement Mortar

Quarry pond fines vary considerably among production sources, making it difficult to determine which materials are suitable for use in cementitious mixtures. This study examines whether commonly measured physical, chemical, and mineralogical properties can serve as practical screening indicators for evaluating the suitability of quarry pond fines as partial replacements for Portland cement.

Quarry pond screening materials obtained from eight granite- and limestone-derived quarries in Georgia were evaluated. The testing program included specific gravity, particle imaging-based angularity, X-ray fluorescence, X-ray diffraction, mortar flow, compressive strength, and scanning electron microscopy. Mortar mixtures were prepared at cement replacement levels of 5%, 10%, and 15%. A control mixture and Class F fly ash mixtures served as reference materials for comparison.

Specific gravity, imaging-based angularity, and mortar flow varied within relatively narrow ranges and did not consistently correspond to the observed strength differences. Bulk oxide composition distinguished the limestone- and granite-derived materials but did not, by itself, explain their mortar performance. Mineralogical composition provided a clearer basis for differentiating the materials. The compressive strength results showed that granite-derived screenings generally maintained higher strengths at 5% and 10% cement replacement, whereas carbonate-rich limestone-derived screenings produced lower 28-day compressive strengths. SEM observations also showed more continuous and compact matrices in selected granite-derived mixtures at moderate replacement levels.

The findings show that routine physical properties and fresh-state workability are insufficient for screening quarry pond fines for cement replacement applications. Mineralogical characterization, combined with limited mortar performance testing, offers a more reliable approach for selecting promising materials and identifying unsuitable sources. Where testing capabilities permit, pozzolanic reactivity testing might further enhance the screening process by directly evaluating the supplementary cementitious potential of quarry pond fines. This integrated approach can support more efficient material qualification and promote the beneficial reuse of quarry by-products in sustainable cementitious construction.