Effects of water absorption on the microstructure of plaster with end-of-life tire rubber mortars

This research studies the effect of incorporating rubber from end-of-life tires (ELT) in plaster matrices on the structure of the composite material. Test samples of plaster are prepared adding different volumetric fractions of rubber, obtained from the mechanical shredding of ELT, in three different grades of coarseness. Values are obtained for water absorption by capillarity and by total immersion and for open porosity. The transition zone between paste and rubber has been studied using scanning electron microscope (SEM) techniques. The incorporation of ELT-rubber causes a second porosity, smaller than that associated with the plaster matrix, producing smaller crystals which confirm the reduction in resistance and improving thermal and acoustic insulation tests.