UTILIZATION OF SPENT ANTHRACITE FILTER MEDIA IN CEMENT MORTAR: STRENGTH AND DURABILITY ASSESSMENT

This study investigates the utilization of spent anthracite filter media (SAFM) as a sustainable fine aggregate to partially replace natural sand in cement mortar.The experimental program evaluated the effects of SAFM replacement at 10%, 20%, and 30% by volume on the flowability, density, mechanical properties, and chemical durability under aggressive environments (NaCl, MgSO₄, and H₂SO₄).Mortar mixtures were prepared following ASTM standards with a constant water-to-cement ratio of 0.43.The results revealed that increasing SAFM content reduced the flow value from 115% (control) to 100% (30SAFM) and slightly decreased the density from 2136.0 to 2028.0 kg/m³ due to the lower specific gravity of SAFM.In contrast, the compressive and flexural strengths increased significantly by approximately 46% and 21%, respectively, at 30% replacement, indicating improved interfacial bonding and pore refinement.Durability tests demonstrated that SAFM enhanced resistance to chloride and sulfate attack, particularly under MgSO₄ exposure, where compressive strength after 90 days increased by 48% compared with the control.Although all specimens deteriorated under acidic conditions (H₂SO₄), SAFM delayed surface damage and mass loss.The findings confirm that SAFM can serve as an effective and ecofriendly alternative to natural sand, offering enhanced strength and durability while promoting the circular economy through waste reuse in sustainable construction materials.