Investigating the Mechanical Performance of Concrete by Incorporating Poultry Slaughterhouse Wastewater Treatment Plant Sludge as a Partial Cement Replacement

Poultry slaughterhouse wastewater sludge (PSWS) is a by-product of wastewater treatment, increasing with poultry meat consumption. Disposing of this waste has led to its investigation as a supplementary cementitious material in construction, due to its Calcium and Iron content. Mortar specimens were produced with 5%, 10%, and 15% sludge replacements, using both air-dried and oven-dried sludge. Compressive strength tests on 2”x2” mortar cubes determined the optimal sludge-to-cement ratio. This was applied to 4”x8” concrete cylinders, tested for compressive and split tensile strength, and 6”x6”x21” beams, assessed for flexural strength. Results showed that 5% sludge concrete had lower compressive and split tensile strength than the control mix at all ages, significantly so at 28 days. Flexural strength, however, was higher in 5% sludge specimens at 7 days but lower by 28 days. Incorporating 5% sludge in concrete reduced compressive and tensile strength but increased flexural strength, suggesting its use in non-load bearing structural elements.