A performance characteristic models of properties of dissolved plastic bottle modified bitumen for hot mix asphalt production

This paper investigated the effect of recycling Polyethylene Terephthalate (PET) waste bottles in dissolved (liquid) miscible forms (1, 3, 5, 7, 9, 11, 13, 15 and 17% by the weight) on the properties of standard straight-run grade bitumen. Classification, strength & safety compliance properties were carried out, according to provisions of standard testing procedures, at different percentages of (0-17) dissolved PET. Quantitative explanation of models for the trend of the variation of these properties were developed for each property with respect to % PET. Models were later compared with the corresponding statistic. The developed models for ductility, penetration, softening point, viscosity, flash and fire points, and specific gravity of the modified bitumen were -2.185(%PET) + 79.399, 2.456(%PET)  + 47.401, -3.149(%PET)  + 92.909, 1.244(%PET) + 75.622, 2.6801(%PET)  + 254.69, 2.2036(%PET) + 307.65 and 0.0042(%PET) + 0.9589 with R2 values of 0.976, 0.969, 0.992, 0.976, 0.9917, 0.9774 and 0.9881 respectively. Results revealed that addition of PET (0 – 17 %) increased the softening, viscosity, specific gravity, flash and fire points of bitumen but decreased the penetration and ductility. It is concluded that PET can be used to improve the classification properties only but less for the mechanical properties of asphalt binder. However, satisfactory values which are in conformity with Nigerian, American and British standard specifications can be met at % PET of  ≥2.01, ≥3.52, 11.09 – 14.58, 4.92 – 9.20, ≥1.98, ≥5.60, and ≥9.79 for ductility, viscosity, softening point, penetration, flash point, fire point and specific gravity respectively.