Characterising impact resistance of latex–cement mortars for external insulation systems

The effect of various redispersible powders on the impact resistance of latex–cement composite mortars for external insulation and finishing systems (EIFS) was investigated. A set of eight polymer mortars, using different polymer technologies and exhibiting different glass transition temperatures, were tested for impact resistance. It was observed, on mortars prepared with 5·8% latex redispersible powders, that the intrinsic properties of the polymer used in the EIFS latex mortars have no effect on the material resistance to impact loading. The impact resistance of the mortars mainly depends on their capacity to absorb and dissipate energy from dynamic loading. A methodology to analyse the capacity of the mortars to absorb impact energy is proposed using the evaluation of the consumption energy ratio (E_f/E_t) between the energy dissipated at the down point under the load in the bending test and the energy dissipated in the tensile test.