The Effect of Different Natural Porous Aggregates on Thermal Characteristic Feature in Cementitious Lightweight Mortars for Sustainable Buildings

In recent years, thermal insulation and thermal comfort have gained great importance in buildings. Natural porous lightweight aggregates have a potential of greatly improvement on thermal insulation properties of cementitious products. However, its thermal insulation properties should not be evaluated solely with the thermal conductivity coefficient. This experimental study is devoted to determining the thermal comfort properties, namely thermal conductivity, thermal diffusivity, specific heat value, heat storage capability and heat storage efficiency of tested mortars for building applications. Within this scope, four different porous natural aggregate types were tested as lightweight aggregates for thermal insulation properties. These lightweight aggregates are pumice, volcanic slag, tuff and diatomite. The results show that the apparent porosities of the test specimens were quite high. As a result of this property, thermal conductivity values decreased considerably compared to the control specimen (up to 79.39%). Also, it is concluded that density and porosity ratio of the aggregate used in the preparation of the mortar specimens is an effective parameter on the specific heat of the material. The mortars produced by the volcanic slag, pumice, tuff and diatomite aggregates appear to be effective in heat storage. Additionally, it has been determined that the thermal characteristics of the materials change depending on the aggregate chemical structure. For this reason, the major chemical components of all mortar specimens were examined chemically, and the findings were tried to be associated with the thermal characteristics.