In the present study, the usability of the pumice of the Isparta-Karakaya those categorized in the light aggregate class, have been examined in terms of stabilization material in the subbase considering volumetric unit weight. Initially, the physical properties of lightweight aggregate material have been analyzed. It has also been researched if it is possible to use in a subbase layer or not. For the research, few experiments have been carried out by using experiment samples such as stability to freeze, solidity, strength, Atterberg limits and California Bearing Ratio (CBR). The usability of the stabilization material has been determined in the subbase layer. Pumice of Isparta-Karakaya which is a local material and Capah land material have been mixed in different amount to lessen the percentage of plastic limit. Then, the limit experiment has been done. The CBR experiment has been performed to observe the change of strength by the use of the obtained renascent usable material. At the result of the experimental research, it has been observed and determined that pumice can be used as subbase material of highway and the stabilization material when building highway and every kind of road and it has also been observed and determined that the increased strength of the mixed material. (c) 2007 Elsevier Ltd. All rights reserved.