Modification of roadbed soil by crushed glass wastes

Abstract

This study aims to use the crushed glass obtained from waste flasks to improve the properties of the weak roadbed soil. The study included crushing and powdering waste flasks. Afterward, the crushed glass was sieved and separated into three classes depending on the particle size: class A contains particles with diameter less than 4.75 mm and more than 1.18 mm, class B contains particles with diameter less than 1.18 mm and more than 0.08 mm, and class C contains particles with diameter less than 0.08 mm. For each of these classes, 6 different crushed glass contents were mixed with a weak roadbed soil to study their influences on its engineering properties. To attain this objective, four laboratory tests were applied: California Bearing Ratio (CBR), which determines the bearing value and the swelling ratio, triaxial compression test under cyclic loading, which determines the resilient modulus (M_R), and the Oedometer test, which determines the compressibility coefficients (C_c and C_r). The results showed that increasing the crushed glass content enhances the tightness of the roadbed soil and reduces its volume changeability. Nevertheless, the use of class C showed the highest enhancement compared to the other two classes. Compared with original roadbed soil, CBR values and resilient modulus (M_R) values ​​of the roadbed soil samples mixed with 18% of class C of the crushed glass were increased to more than 8 times and 4 times respectively. In addition, swelling ratio, C_c, and C_r were reduced to 53%, 50%, and 35% respectively.