Microstructure of Composite Material from High-Lime Fly Ash and RPET

Tests on composite material from high-lime (ASTM class C) fly ash and recycled polyethylene terephthalate (RPET) were conducted to investigate the physiomechanical properties and microstructure features. Composite specimens with varying fly ash concentrations were tested in compression and tension, immersed in water to measure water absorption, and observed for shrinkage during manufacturing. Theoretical equations from modulus of elasticity and tensile strength were derived with values compared to portland cement concrete. Microstructural features associated with crack propagation during compression loading and the RPET binding mechanism were studied utilizing scanning electron and polarized reflective light microscopy and differential scanning calorimetry. The results of this investigation showed that the fly ash concentration contributed significantly to both the strength of composite material and the crystallinity of the RPET binder. Based on the evidence, it was concluded that the composite material is a value-added material with a variety of potential construction applications.