Rice husks are major agricultural by-product obtained from the food crop of paddy. Generally, it is considered a valueless product of rice milling process. Chemical analyses have shown that the ash i.e. rice husk ash (RHA), is a highly reactive pozzolanic material. RHA contains a high amount of silica dioxide suitable for use in lime pozzolana mixes and Portland cement replacement. On this ground the contribution of rice husk ash to the engineering application needs further investigation. This research concerned with the effect of the adding RHA to lime-treated expansive soil on its engineering properties. This includes the study on the swelling behaviour of untreated and treated specimens. Experimental soils are prepared by mixing commercially available clay minerals with sand in different proportions to obtain a wide variety of soil characteristics. The basic clay minerals used are bentonite and kaolinite. A series of laboratory work is conducted to study the change in of physical and geotechnical properties of expansive soils, including durability and serviceability. A mixture design and testing procedure for lime-RHA treated soils are established as outcome of this research.