Numerical finite element simulation of temperature effects on the compressive strength of RPET-modified mortars

This study analyzes the compressive behavior of concrete modified with recycled polyethylene terephthalate (RPET) through finite element modeling using SolidWorks Simulation. Cubic specimens were modeled with 10% and 20% RPET content, then exposed to three different temperatures 20°C, 150°C, and 350°C under two curing conditions: ambient air and curing in water. The purpose was to evaluate how the polymer content, temperature, and curing method impact the compressive strength, load capacity, and failure patterns of the material. Numerical models successfully predicted stress distribution, the effects of thermal degradation and the evolution of deformation. The results revealed that water curing significantly improved compressive strength, with 10% RPET specimens reaching 30.70 MPa at 20°C compared to 14.20 MPa for air-cured specimens, an increase of 116%. The increase in temperature caused severe degradation, with strength losses of 48-71% at 350°C, depending on the RPET content and curing conditions. Specimens with 10% RPET showed superior mechanical performance and thermal stability in all test scenarios. The finite element method validated its effectiveness as a predictive tool for optimizing sustainable cementitious materials incorporating plastic waste, enabling design optimization without extensive experimental testing.