Polyethylene Terephthalate (PET) plastic particles, having been functionalized using a simple, cost-effective, and scalable treatment technique, presented in patented application 17484834, were used as a cement replacement ingredient in plain cement beams. The functionalization increases the affinity of PET to water, and thus their hydrophilicity, enabling the particles to form bonds with Ordinary Portland Cement (OPC) hydration products. The particles were randomly distributed into cement powder during the mixing process. Size effect beams of 4 different geometrically similar sizes were cast in three different percentages (families) of cement replacement with functionalized PET in notched beams to be tested in three-point bending. Bažant’s Type 2 Size Effect Law was used to elucidate the size effects and initial fracture energies (Gf) of all families. The Hillerborg Work-of-fracture method was used to find the total fracture energy (GF). Preliminary results indicate that beams with adequately bonded PET demonstrated improved ductility, caused by crack bridging, as well as increased i) fracture process zone (FPZ) size, ii) Gf and iii) GF, compared to reference OPC beams, while closely preserving the bending strength for larger sizes.
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