Effect of the nature of clayey soils (Eastern Morocco) on the thermophysical properties of bricks

Abstract

Local building materials are gradually replacing expensive and energy-intensive manufactured products. The present paper compares the mineralogical and thermophysical properties of two different soils from eastern Morocco (soil A, Ouled Setout, Nador city; soil B, Touissite, Jerada city), which are extensively employed in the brick-making industry at the national level. Firstly, the geotechnical and mineralogical analyses were carried out for soil identification. The influence of the physical and mineralogical composition of soil on the thermal transport properties of clay bricks was examined using the hot disk method. Except for the calcite content, X-ray diffraction and thermal gravimetric analyses showed almost the same mineralogical composition of soils. Furthermore, plasticity testing showed high plasticity for both soils. Thermal results found that soil B has a lower thermal conductivity than soil A, which may be ascribed to the high sand content that provides more porosity responsible for better thermal insulation. In order to analyze the building energy savings, the thermodynamic behaviour of a residential building constructed with unfired and fired clay bricks manufactured from the soil B were simulated using TRNSYS. Numerical results showed that unfired clay bricks are more thermally efficient than fired bricks, resulting in energy savings per constructed square meter of 4% for heating and 1.65% for cooling in buildings located in semi-arid climates.