OPTIMIZATION CONDITIONS OF RECYCLING WASTE PLASTIC PETON ASPHALT, BY USING APPLICATION OF RESPONSE SURFACE METHODOLOGY

In this study, different conditions of waste plastic PET (Polyethylene Terephthalate) recycling on asphaltwereoptimized. Response Surface Methodology (RSM) using the Doehlert experimental design has been employed in the optimization. The independent variables considered were bitumen(5-8%), PET (0-12%), mixing temperature (150-160°C) and mixing time (20-30min). Four-second order polynomial models were generated. The responses obtained by the models were well described as: specificgravity (Y. SG), penetration (Y. P),softening point(Y. SP), and flash point (Y.FP) of the process with satisfactory fits in terms of absolute average deviation, bias factor and accuracy factor. The optimum responses were 1,05 g/cm³ as specificity gravity (Y. SG), 60*(1/100mm)as penetration at 25°C, 100g and 5sec(Y. P), 50°C as softening point (Y. SP), and 244°C as flash point (Y. FP). The statistical relation between the four independent variables and the process responses was well described.