High-Temperature Degradation of Mortar Containing Rubber Aggregates and EVA Binder Evaluated by Impact-Echo Method

The application of Impact-echo acoustic method to evaluate the degradation and the composition of mortar composites modified with rubber aggregates and EVA polymer binder degraded at high temperatures was studied. Specimens were prepared by using a type CEM I Portland cement and siliceous sand, as well as by substituting 25% of sand with shredded automobile tires and by adding of EVA polymer binder (10% w/w to cement mass). The samples were subjected to high-temperature treatment in the temperature range of 200-400 °C. The results of non-destructive testing of such samples by acoustic methods confirmed the differences in the structure of mortar specimens. Addition of rubber aggregates in samples caused absorption of lower frequency as compared to reference specimens. A significant decrease of the absorbed frequencies was observed depending on the temperature. The largest decrease happened after exposure of samples at 200-300 °C. It indicates that the effect of heat treatment was reduced when the EVA binder was added.