Effect of pore forming agent on the properties of lightweight expanded clay aggregate

Abstract

Lightweight expanded clay aggregates (LECA) were produced by using clay, coal, perlite, and bottom ash. Aggregates were shaped by means of pelletizing. After preparation, the rounded aggregates were treated for various firing temperatures ranging from 900 to 1200 °C in an electrically heated furnace. The specific gravity, water absorption properties and microstructures of the granules were determined. Test results revealed that specific gravity (SG) values decreased as the coal addition increased. Slight rises were observed in SG values with the increase in heat treatment temperature up to 1180 °C for coal used recipes. However, there was a sharp increase in SG beyond 1180 °C. The effects of amount of perlite and the heat treatment temperature on SG values of LECA granules could not be generalized. The effect of bottom ash addition on SG could not also be generalized.