The Performances of Rice Husk Ash and Alumina Paste in The Development of Lightweight Composite Bricks

The lightweight brick composite has been produced by rice husk ash waste and alumina paste as a novel material with low density. This study aimed to evaluate the performance of lightweight concrete brick composites incorporated with rice husk ash and alumina and to obtain the dimensions, compressive strength, water absorption, and thermal conductivity values. Four mixtures of lightweight composite concrete bricks were produced by replacing 5%, 10%, 15%, and 20% (by weight) of the fine sand with rice husk waste ash and one mixture without rice ash. In all mixtures, 5% (by weight of all material) of alumina paste was added as a foaming agent. All composites of lightweight bricks were produced using steel molds. The resulting composite bricks show a density value lower than 500 kg/m3 with a 0.094 W/mK of thermal conductivity, thus having properties of lightweight concrete. The highest compressive strength value of the lightweight brick composite was 3.35 Mpa by adding 5% rice husk ash. All of the lightweight brick samples developed showed no significant change in shape when measured dimensionally. All mixes had water absorption values less than 25%. As a result, employing rice husk ash waste as fine aggregate in lightweight concrete bricks is regarded as a viable method of recycling this waste material.