Effect of fly ash, construction demolition waste and lime on geotechnical characteristics of a clayey soil: a comparative study

Improvement of strength and subgrade characteristics of soil by stabilization is one of the popular techniques nowadays. The use of construction demolition (C&D) waste in soil stabilization is still under research as much work has not been done in this area. This paper presents a comparative study of utilization of fly ash, C&D waste and lime in soil stabilization. A number of tests such as differential free swell, pH, compaction, unconfined compressive strength (UCS) and California bearing ratio (CBR) were conducted to study the effect of addition of fly ash, C&D waste and lime on geotechnical characteristics of soil. Based on results, it is concluded that differential free swell and maximum dry density decrease, whereas pH, UCS and soaked CBR value increase with addition of fly ash, C&D waste and lime. The increase in UCS is almost the same for lime and C&D waste at 7 days which indicates that the usage of C&D waste compared with that of lime is economical, whereas if used in pavement subgrade lime is better material because of higher CBR value. The UCS at 28 days is more for fly ash compared with that for lime and C&D waste.