Lightweight expanded clay aggregates are one type of artificial lightweight aggregates (LWAs)whichhavewide-spread application. They are produced in a rotary kiln. Output aggregates of kiln often contain a wide grading
curve. The micromechanicsmethodwith some simplifications has beenused for determining theelasticmodulus
of the different sizes of these aggregates. In general, the smaller the LWA particle size, the higher is the density.
The effect of the density and size of aggregates on elasticmoduli are investigated in this research. Two groups of
quaternary lightweight expanded clay aggregates are used, with each group produced under the following iden-tical conditions: particle density within the range of 480 to 1100 kg/m
3
and the domain sizes from 4 to 14 mm.
The elasticmodulus of expanded clay aggregateswere determinedby the micromechanicsmethod andusing the
Mori–Tanaka model basedon the elasticproperties ofmortarmatrix and lightweight concretewhich were deter-mined experimentally. Basedon results the elasticmodulus of aggregates ranged from 0.6 to 6.3GPa and there is
a linear relation between the elastic modulus and the particle density of lightweight expanded clay aggregates.
Their elastic modulus exponentially decreases with the increase in particle size.