Effect of Lime Sludge and Fly Ash on Unconfined Compression and Linear Shrinkage Behavior of Kaolinite Clay

The paper investigates the use of lime sludge (LS), fly ash (FA) on unconfined compressive strength, and shrinkage behavior of commercially available kaolinite clay (EPK). The stabilization process was done using lime sludge alone with varying percentages i.e., 2, 4, 6, and 8% by dry weight, as well as a combination with fly ash in varied percentages i.e., 5, 10, 15, and 20% by dry weight. In order to evaluate the strength properties, standard Proctor tests, and unconfined compressive strength (UCS) tests were performed. For estimating the shrinkage, linear shrinkage test was carried out. The UCS samples were prepared based on the optimum moisture content and dry unit weight from standard Proctor tests. The samples were tested after a curing period of 0, 7, and 14 days. In addition, Scanning Electron Microscopy (SEM) tests were performed on UCS samples after shearing. The test results indicated an increase in UCS value with an increase in lime sludge content. Also, the UCS value increased with curing period following a slight decrease. The combination of LS and FA in varied percentages, also had an increase in UCS strength. Also, the UCS value showed an increment in values with the curing period. The reduction in shrinkage behavior of EPK clay was observed with LS and FA. The SEM analysis was conducted to evaluate the reason for strength increase, which was due to the chemical reaction developed between EPK clay, lime sludge, and fly ash.