Gamma Rays as Modifiers of the Compressive and Flexural Properties of Polyester Polymer Concrete

Abstract

To improve the mechanical and thermal properties of materials, alternative posttreatments have been proposed. One of these posttreatments is based on the use of ionizing radiation. This work studied the effects of gamma rays on the mechanical and thermal properties of polymer concrete (PC) produced with 80% silica sand and 20% polyester resin. High gamma irradiation doses (100–500 kGy) were used. Mechanical properties (compressive and flexural strength), and thermal properties (thermal conductivity, specific heat, and thermal diffusivity) were analyzed. The results show that the highest values of compressive and flexural strength and elasticity modulus occur when polymer concrete is irradiated at 400 kGy. The compressive strength of the reference concrete was 51 MPa; this resistance increased to 62 MPa (23% higher) when polymer concrete was irradiated at 400 kGy. The modulus of elasticity increased 12%, from 2.17 to 2.44 GPa, whereas the flexural strength increased from 16.2 to 17.7 MPa (9%). Changes in the thermal properties (mainly the specific heat) were obtained at 100 and 200 kGy doses. The results were related to the surface modifications produced in the irradiated polyester resin (analyzed by scanning electron microscopy) and its chemical structure (studied by Fourier-transform infrared and Raman spectroscopies).