The relation between particle density and static elastic moduli of lightweight expanded clay aggregates

Lightweight expanded clay aggregates are one type of artificial lightweight aggregates (LWAs) which have widespread application. They are produced in a rotary kiln. Output aggregates of kiln often contain a wide grading curve. The micromechanics method with some simplifications has been used for determining the elastic modulus 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 elastic moduli are investigated in this research. Two groups of quaternary lightweight expanded clay aggregates are used, with each group produced under the following identical conditions: particle density within the range of 480 to 1100 kg/m3 and the domain sizes from 4 to 14 mm. The elastic modulus of expanded clay aggregates were determined by the micromechanics method and using the Mori–Tanaka model based on the elastic properties of mortar matrix and lightweight concrete which were determined experimentally. Based on results the elastic modulus of aggregates ranged from 0.6 to 6.3 GPa 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.