Production of lightweight aggregates by sintering minerals and industrial wastes

In this thesis, pellets in the form of sphere were produced by mixing the expanded clay with water. Light weight aggregates were produced by rapid sintering the dried pellets in a laboratory oven at 1100 °C for 4 minutes. While forming the sample groups, four main variables were determined. These were the different sizes of the expanded clay (<63µ, 63-125µ, 125-250µ, 250-500µ, >500 µ and 0-1 mm), 20% by mass zeolite (Z) or fly ash (FA) replacement, 24, 27 and 30% water/binder ratio and pellet size (4, 8 and 12 mm). Effect of the mentioned variables on the physical, mechanical, mineralogical and microstructural properties of the light weight aggregates were investigated. When the grain size of the aggregate was reduced; water requirement and the expansion rate increased and the compressive strength decreased. With the UK substitution, the amount of glassy phase, the strength and the unit weight increased. For Z substitution, the amount of voids decreased and the compressive strength increased. The use of UK and Z reduced the amount of expansion. As the amount of water increased, the amount of expansion generally increased. When the pellet size decreases the thickness of the aggregate shell and the compressive strength of the aggregate increased. The increase in clay content increased the glassy phase content and the expansion amount of the aggregate. Keywords: Expanded clay, Fly ash, Light weight aggregate, Micro structure, Zeolite