Waste polymers and gamma radiation on the mechanical improvement of polymer mortars: Experimental and calculated results

Abstract

In this work, the effects of waste polymer particles and gamma radiation on the mechanical properties of polyester mortars were studied. Control mortar was elaborated with polyester resin (20%), and silica sand (80%). This last was partially substituted by each waste polymer (1, 2 and 3 wt. %), namely, i) PET from beverage water bottles, ii) Polycarbonate from computer monitors and displays, and iii) Waste tire rubber from automotive tires. A post-curing process was applied to polyester mortars by using gamma rays (at doses of 100 and 200 kGy). Analysis of the results were made according to irradiation dose and the particles concentration. We reminded that such polymer mortars are used in applications where high mechanical and chemical attacks resistance are required, moreover they are friendly to the environment. The results show, that the effect of the ionizing radiation was predominant, because higher percentages of improvement on the mechanical properties were obtained, up to 46% for irradiated mortars with PET particles, and up to 37% for those with polycarbonate particles, respect to that for control mortar. Respect to the waste particles concentration, a general behavior was obtained: mechanical properties decrease gradually with increase of particles concentration. Nevertheless, it was remarkable to use only 1% of waste particles concentration, for to obtain the highest values for both kind of mortars, non-irradiated and irradiated. The experimental results were simulated by Finite Element Method (FEM), both were in good accordance, having minimal difference between them. In addition, morphological modifications of each waste polymer after irradiating, were analyzed by scanning electron microscopy (SEM) and related to mechanical behavior of polyester mortars.The improvements in the mechanical properties of the composites, as well as the use of waste polymers, make these polymer mortar environmentally friendly construction materials that can be used in applications that require high mechanical resistance. Keywords: Waste polymer, PET, Polycarbonate, Tire rubber, gamma radiation, Polymer mortar, Mechanical properties, FEA method, ANSYS program