Properties of Foamed Concrete Produced with Rice Husk Ash as a Partial Replacement for Cement

Abstract

This study investigated foamed concrete strength characteristics produced with rice husk ash (RHA) as a partial replacement for cement. RHA is used as cement replacement to help reduce the amount of solid waste released into the environment, reduce greenhouse gas release into the atmosphere as a result of cement production, and reduce the amount of cement used in concrete production. The study examined workability, plastic and testing densities, split tensile and compressive strength, and modulus of rupture at an intended design density of 1600 kg/m³. A cube specimen measuring 100 mm was used to measure the density and compressive strength, 100 x 200 mm cylinder specimens were used for splitting strength, and unreinforced beams measuring 100 x 100 x 500 mm were used for the modulus of rupture test. A known-volume container was used to study the plastic's density, and the spread test was used to assess its stability. RHA was added to foamed concrete (FC) at various percentage replacements of 0% (control), 5, 10, 15, 20, 25, and 30% by weight of cement, and cured in a membrane (sealed) curing condition for 7, 14, 28, 56, and 90 days. The findings show that an increase in RHA content reduces the density of foamed concrete in both wet and dry states. The control sample compressive strength value is 15.22 N/mm², the modulus of rupture value was 2.51 N/mm², and the split tensile strength was 1.68 N/mm², at 28 days of curing. The results of this investigation demonstrate that, whereas other percentage levels indicate decreased strength, FC with rice husk ash percentages up to 10% did not significantly differ in strength from the control concrete. The study concluded that FC used for this study has potential for structural applications up to 15% RHA and up to 30% for non-structural purp