Lightweight expanded clay aggregate as a building material - An overview

LECA is the abbreviation of lightweight expanded clay aggregate. LECA is produced from special plastic clay with no or very little content of lime. The clay is dried, heated and burned in rotary kilns at 1100-1300 °C. LECA is porous ceramic product with a uniform pore structure with almost potato shape or round shape due to the kiln circular movement. The abundant numbers of small, air-filled cavities in LECA give its lightweight, thermal as well as sound isolation characterizes. In this article, the earlier studies which focused on using LECA as a part of building materials in traditional cementitious materials, as well as inorganic polymers (geopolymers), have been briefed. Furthermore, various materials which added to modify some properties of LECA concrete and mortar have been briefed and reported. The main findings of this review are the incorporation of LECA in the matrix increased its workability, decreased density, decreased mechanical strength, decreased freeze/thaw resistance, increased water absorption, decreased chloride penetration resistance, but increased thermal insulation and fire resistance.