Optimizing Cement Mortar Performance with Black Sand: A Study of Mechanical and Durability Properties
Volume Title: ICASGE2025
Paper ID : 1160-ICASGE (R1)
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Abstract
This study explores the use of black sand (BS) as a fine aggregate in mortar mixtures, examining its effects on mechanical and durability properties. Two groups were prepared: Group M (Portland cement as binder) and Group F (25% fly ash replacement). BS replacement ratios ranged from 0% to 100%, and mixtures were tested for compressive strength, fire resistance, and sulfate resistance. Results show that the optimal BS replacement ratio is 20% to 40%, with higher ratios reducing strength. Fly ash (FA) improved compressive strength, especially at later ages, due to its pozzolanic and filler effects. BS-based mortars exhibited enhanced fire resistance at 200°C, attributed to BS minerals (e.g., Fe2O3, Ti, Si), but failed at 400°C due to internal vapor pressure. FA also improved sulfate resistance by blocking capillary pores, reducing sulfate penetration. The study concludes that BS, combined with FA, enhances mortar properties, but ratios above 60% should be avoided. These findings support sustainable construction using locally available resources.
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