Influence of mud waste and straw grass addition in fired bricks production: technical properties evaluation

For ages, the building materials industry has made use of mud bricks as the simplest and most ecological class of natural construction material. In the current scenario, the industry has focused on developing new technological engineered building materials to minimize non-renewable resource use and boost building enclosures comfort. In the present study, mud construction and demolition (MCD) rubble and straw grass material (SGM) made from Pennisetum purpureum plant have been combined with clay material to produce modeled fired clay bricks (FCB). The raw materials were characterized for their physical, chemical, mineral and thermal properties, and found suitable for use in FCB formulation. Several experimental tests including linear shrinkage, weight loss on ignition, apparent porosity, compressive strength, fired density and thermal conductivity were carried out to evaluate the influence of these wastes on the technical quality of the bricks. The various tests showed that bricks containing 15 wt% MCD and 7.5 wt% SGM were the most optimized samples as these bricks exhibited compressive strength values of 10 MPa for load-bearing structural construction application, 1.67 g/cm(3) fired density and 0.56 W/mK thermal conductivity that represented 30% improvement in thermal insulation.