Using sewage sludge ash and stone powder in soil stabilization and concrete mixtures

In this study, two different types of wastes (Sewage Sludge Ash SSA and Stone Powder SP)wereused as a stabilizer to improve some geotechnical properties of silty soil and as alternatives of cement and sand in concrete mixtures. Five different ratios (in weight percentage: 0%, 5%, 10%, 15%, and 20%) of SSA and SP admixtures are mixed with cohesive soil to make soil samples. Also the materials used with four different ratios (0%, 10%, 20%, and 30% in weight) in 1:2:4 (cement: sand: gravel) concrete mixtures. In order to understand the influences of admixtures on the soil properties, tests of Atterbeg limits, compaction, unconfined compressive strength, fall cone, laboratory vane shear, and primary swell were performed on those samples. Another test of compressive strength was performed to 28-days cured concrete samples. The study shows that the unconfined compressive strength of specimens with the SSA addition was improved and with the SP addition was reduced; furthermore the undrained shear strength obtained from fall cone and laboratory vane shear tests was increased in both SSA and SP addition. The strength of concrete samples contained SSA and SP was adversely affected with increasing the SSA and SP ratios in the mixtures. This suggests that SSA and SP have many potential applications in the field of geotechnical engineering and can used to reduce the cost of non-structural application such as road pavement, walkways, and floor works.