DefinePK

Abstract

Crushing strength of lightweight aggregates depends on the efficiency of production, type of binder used and size of the aggregate formed. Fly ash based slag pellets were produced in the present study by pelletization process. The pellets consist of fly ash and furnace slag as binder substituted at 10%, 20% and 30% by the weight of fly ash. A disc pelletizer was set to an angle of 36º with a speed of 55 rpm and pelletization duration of 10 minutes and 15 minutes was adopted. Hardening of cold bonded fly ash aggregate was carried out in hot air oven at 100ºC. The crushing strength of different size ranges of cold bonded aggregate was tested at different ages. Test results showed that the strength gain of pellet depends on the percentage of binder added and pelletization duration. A significant strength improvement is noticed at higher duration (15 minutes) (mix combination of 80% fly ash and 30% furnace slag added with concentration of 10M of NaOH) compared to 10 minutes pelletization duration. Also, the strength reduction was noticed with the increase in the size of pellets; due to size effects. The crushing strength of smaller size pellets (6 mm diameter, 30G2) exhibited higher strength (43.88%) than the larger size aggregate (16 mm diameter, 30G2) and a significant reduction in strength was noted for bigger sized aggregates due to size effect.