Cold bonded fly ash lightweight aggregate containing different binders

Abstract

The potential applications of artificial aggregate in light weight concrete construction and prefabricated concrete elements are on the huge demand. This study investigates the production of alkali activated flyash aggregate containing different types of binders such as metakaolin, furnace slag and bentonite. The lightweight aggregate properties are greatly altered with the addition of binder material which can result in good binding properties to the flyash aggregate. The production of activated fly ash aggregate depends on the type and dosage of binders in the pelletizer. Pelletization process depends on the efficiency of production, gradation and crushing strength of aggregates which depends on the type and percentage of binder used, angle of disc, speed of disc and duration of pellet formation. The fly ash aggregates were produced and the effects of various binder materials (furnace slag (GGBS), bentonite and metakaolin) substituted at 10, 20 and 30% respectively of total binder material for various time duration were studied. The effect of alkali activator (sodium hydroxide) at a concentration of 8, 10 and 12 M, respectively were studied in flyash aggregates and the aggregates were cured in the hot air oven at 100°C up to 7 days. Test results also exhibited that water absorption flyash aggregates made using GGBS binder was found to be lower than (12.88%) compared to bentonite (16.39%) and metakaolin (17.86%). The crushing strength test results showed that a maximum strength of 22.81 MPa was obtained in the case of fly ash-furnace slag aggregate, 17.62 MPa for fly ash-metakaolin aggregate and 14.51 MPa for fly ash-Bentonite aggregate. © Maxwell Scientific Organization, 2014.