Mechanical, electrical properties and impedance spectroscopy characterization of rammed earth

Reducing energy consumption in building sector is one of the most important issues of this century. Indeed, the building sector is the most energy-consuming among the economic sectors, accounting for nearly 40% of global energy consumption. In order to reduce energy consumption in this sector, improving the performance of the building envelope seems to be the most cost-effective solution. The current trend is the valorization of local bio-based materials for building construction and thermal insulation. The use of these materials is one of the potential ways to support sustainable development in both urban and rural areas. In the present article, we propose an experimental investigation on the use of a light-weight construction material, composed of rammed earth. The influence of the grinding on the mechanical and electrical properties is studied. It increases the compressive strength hand gives the material a greater ductility compared to the non-grinded one. The analysis of the electrical behavior of rammed earth is a highly important feature for the renewed interest of its use in the building construction. In this context, electrical impedance spectroscopy technique with frequency varying between 20 Hz and 1 MHz is considered, for the first time, to measure electrical complex impedance. The analysis of the temperature and frequency dependence of the electrical conductivity of any semiconducting material permits the estimation of the activation and relaxation energies for the dominant electrical conduction mechanisms. The experimental curves are compared to the theoretical models of hopping and tunneling processes.