Investigation of the impact of polyethylene terephthalate powder and graphite materials on water absorption, mechanical and rheological properties of concrete

Abstract

This study investigated the impact of incorporating Polyethylene Terephthalate (PET) powder and graphite nanomaterials on the concrete’s water absorption, mechanical and rheological properties. The primary objective was to evaluate how these materials, when used as a partial replacement for cement, influence concrete performance. After characterization, the PET-NANO material was found to be highly crystalline (86.6%). A series of concrete mixes were produced based on a Response Surface Methodology (RSM) design, with varying percentages of nano-sized PET and graphite (from 0% to 5%). Results showed that the inclusion of nano-sized PET and graphite materials generally reduced the slump of the concrete mixes. However, an optimal mix containing 3% PET and 1% graphite demonstrated a significant enhancement in mechanical properties compared to the control mix at 28 days, compressive strength increased by 6.04%, flexural strength by 34%, and tensile splitting strength by 2.7%. This optimal mix also exhibited a 9% reduction in water absorption. Conversely, replacement levels above 3% and using larger particle sizes (1.18mm and 2.36mm) caused a significant deterioration in all measured properties. The study concluded that adding a low percentage of nano-sized PET and graphite enhanced concrete’s strength, but the particle size and replacement percentage are critical factors.