The role of construction and demolition materials in swelling of a clay

The aim of this study was to assess the swelling of a clay treated with various construction and demolition materials (CD) (i.e., crushed brick, dragged asphalt, and crushed concrete paving slab), which are recycled and used for new engineering applications, thereby reducing their potential impact on environment. A comprehensive laboratory evaluation was carried out to examine the swelling of clay mixed with the CD materials at different mix ratios in both California Bearing Ratio (CBR) and oedometer testing equipments. The study has indicated that plasticity index for all mixtures decreases with an increase in the amount of CD materials. The testing procedure employed has an influence on swelling of the specimens. The swelling values obtained in the oedometer testing machines were higher than those obtained in the CBR apparatus. Furthermore, swelling behavior of the clay with different CD materials tested was found to be different from each other. The clay mixed with dragged asphalt pieces had the highest swelling value for all mix ratios tested in both testing equipments, while the clay with crushed brick grains had the lowest swelling.