Strength Characteristics of Concrete Elements Having Aluminum Dross and Styrofoam Food Pack Waste as Partial Replacement of Sand

This paper investigates the feasibility of using aluminum dross and Styrofoam food-pack waste (SFPW) as partial replacements for sand in concrete. An M20-grade concrete (1:2:4 mix, w/c = 0.55) was produced with aluminum dross (5% and 7.5% by weight of fine aggregate) and SFPW (0.5-2.0%). Compressive strength (on 150 mm cubes) was tested at 7, 21, 28, 45, and 60 days, and splitting tensile strength (on 0150x300 mm cylinders) at 7, 21, and 28 days, following British Standard methods. Results show that increasing waste content reduces strength: at 60 days the control mix reached 21.8 N/mm2, whereas the mix with 7.5% dross + 2% SFPW achieved 11.6 N/mm2 (≈47% lower). The optimal waste mix (5% dross + 0.5% SFPW) had 18.2 N/rmrf at 60 days (≈17% below control). All mixes exhibited strength gain over time, but mixes with aluminum dross showed early-age setting delays and slight expansion due to hydrogen gas release. While strength and density decrease with these waste additions, the modified concrete meets non-structural strength requirements and offers environmental benefits by diverting waste. Limitations include lack of durability testing and use of relatively low replacement levels. Implications: such concrete could be used in non-load-bearing applications (e.g. masonry blocks, paving, insulation panels), contributing to sustainability by conserving sand and reusing industrial and plastic wastes.