Preparation and evaluation of waste PET derived polyurethane polymer modified bitumen through in situ polymerization reaction

Polymer modified bitumen (PMB) pavement have gained significant importance in the twentieth century and they now play a very crucial role in the field of road construction in every part of world. However, due to well-known difficulties related to the poor solubility of polymers, high temperature stability, sever manufacturing condition and high polymer cost restricts the use of polymer for bitumen modification. To overcome all these difficulties the present study has attempted to demonstrate a new approach where in situ polymerization of monomers bis(2-hydroxyethyl) terephthalamide (BHETA) (which is synthesized from aminolysis reaction of waste Poly Ethylene Terephthalate (PET)) with diphenylmethane-diisocyanate (MDI) in the body of bitumen for the development of polyurethane based Polymer modified bitumen (BHETA-PU). The resulting BHETA-PU product is comparable performance under laboratory condition with conventional styrene butadiene styrene (SBS) based PMB. To investigate the modified bitumen properties and mixture properties, conventional binder tests (Penetration, Softening Point, Marshall Stability, Hot water Stripping & short-term aging test) and Superpave binder tests (Rotational Viscosity, Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR) were carried out. The result reveals that BHETA-PU show significant improvement of antistripping as well as other physico-chemical properties and Marshall Stabilities. This research studies, therefore, suggests not only a new method for making PMB based on PET but also opens a new chapter for the recycling of waste PET in bitumen concrete roads which may help in easy disposal of waste PET polymer. (C) 2017 Elsevier Ltd. All rights reserved.