Fire resistance and ultrasonic testing of rice husk ash modified foamed concrete

Abstract

Foamed concrete (FC) is a relatively new construction material that has recently gained attention due to its unique properties, such as density and strength-to-weight ratio. This lightweight material makes it easy to form into different shapes and sizes. Its excellent thermal insulation makes it popular for building walls, roofs, and floors. This study investigates the fire resistance and ultrasonic testing of rice husk ash modified foamed concrete. The study adopted a design density of 1600 kg/m³ and a 0.5% water-cement ratio. The concrete was cured in ambient conditions at 7,14, 28, 56, and 90 days. A cube specimen of 100 mm size was used to determine compressive strength, density, fire resistance, and ultrasonic pulse velocity (UPV). The control achieved the maximum compressive strength at 28 days, which achieved 15.85 N/mm². The fire resistance of FC is reduced as temperature increases. The strength of FC at an elevated temperature of 400⁰C is minimally reduced. The results proved that the UPV was efficient in proving that the various samples of FC come from the same material (uniform and homogeneous structure) and are classified as good-quality concrete. The findings of this study show that FC with rice husk ash percentage up to 10% did not have a significant difference from the control concrete, while a higher percentage replacement level shows reduced strength. FC is recommended for application in structural lightweight insulating material. RHA is a good pozzolana and can reduce overburden on cement by reducing the quantity of cement used for FC production.