Mechanical, durability and fire performance of lightweight foamed concrete incorporating rice husk ash as cement substitute

Abstract

Foamed concrete is a relatively new building material; knowledge of the materials used in the production and the understanding of the reaction of such material will facilitate the design, performance, and behavioural prediction of such concrete products. This study investigated the mechanical, durability, and fire performance of lightweight foamed concrete incorporating rice husk ash as a cement substitute. The 0, 5 and 10% RHA replacement of cement in concrete has a dry density of 1685 kg/m³ , 1680 kg/m³ , and 1680 kg/m³ respectively, at 28 days of curing time and a maximum compressive strength of 14.79 N/mm² , 14.74 N/mm2, 14.69 N/mm² , with maximum tensile strength of 1.59 N/mm² , 1.55 N/mm² , 1.54 N/mm² and maximum flexural strength of 2.46 N/mm² , for 0, 5 and 10% respectively. The 28-day compressive strength result met standard requirements from either the ACI or BS standards. The compressive strength of foamed concrete is reduced when subjected to higher temperatures of 600 °C and 800 °C. The Ultrasonic pulse velocity increases as the percentage of pozzolana is reduced in foamed concrete. The model has been validated up-to 30% replacement of cement with RHA, and it can be concluded that the model is valid for foamed concrete produced with and without RHA. 10% rice husk ash was the optimal percentage for producing foamed concrete with rice husk ash. It was recommended that using foamed concrete with RHA for semi-structural and structural applications shows potential and encouraging results.