Mechanical and thermal analysis of coating mortars with partial replacement of aggregate by expanded clay

Abstract In the construction industry context, the performance of constructive elements is a relevant topic for scientific research. Hence, the aim of this study was to analyse the mechanical and thermal behaviour of lining mortars, using different contents - 10%, 20%, 30%, 40% and 50% - of a fine fraction of expanded clay as a partial substitute for the conventional aggregate, in order to compare them with a reference mortar without expanded clay. With that purpose, important mechanical properties of the mortars were identified, both in the fresh state and in the hardened state. In addition, the thermal conductivity of the mortars was determined and laboratory tests were carried out on the samples with the aid of incidence and heat transfer simulators. The results show that the mortars incorporating expanded clay did not present negative impacts on their mechanical properties. On the other hand, the increase in the expanded clay content in the composition of the mixes reduced the thermal conductivity and increased the thermal insulation of the samples. Thus, the influence of light aggregate on the thermal behaviour of the mortars under study is evident, without compromising their mechanical behaviour.