Some types of clay are capable of being expanded. These 1100-1300 degrees C when heated in (shock method), they turn into a mass full of bubbles. The volume of gas output and aggregate increases about 5-6 times during expansion process. Expanded clay aggregates are preferred for lightweight construction materials because of both light and hard outer surface sintered. Such a choice because the reduction of dead load, but also has the advantage that the desired level of compressive strength.