PERFORMANCE EVALUATION OF PLASTIC MODIFIED BITUMEN WITH HYDRATED LIME

The persistent challenge of plastic waste management in Nigeria, coupled with the need for moredurableroadconstructionmaterials,motivatesthisresearch.Thisstudyinvestigatesthe potential of using hydrated lime as an adhesion promoter to enhance the performance of bitumen modified with polyethylene terephthalate (PET) plastic waste. The research evaluates the physical properties of a 60/70 penetration grade bitumen modified with shreddedPETatconcentrationsof6%,8%,and10%byweightofthebitumen.Eachofthese blends was subsequently modified with hydrated lime at dosages of 0.5%, 1.0%, 1.5%, and 2.0%.Standardlaboratorytests,includingpenetration,softeningpoint,specificgravity,and flashpoint,wereconductedtocharacterizethebinders.Theresultsindicatedthattheaddition ofplasticwastesignificantlystiffenedthebitumen,withpenetrationdecreasingfrom69mm to 40.1 mm and the softening point increasing from 52°C to 60°C at 10%PET content. The subsequent addition of hydrated lime further amplified this effect, consistently reducing penetration and increasing the softening point across all plastic concentrations. The combinationof10%PETand2.0%limeproducedthestiffestbinder,withapenetrationvalue ofapproximately30mm.ItwasconcludedthatbothPETandhydratedlimeactaseffective stiffening agents, improving the binder's resistance to deformation at high temperatures. However,thestudyalsonotedthathighconcentrationsofbothadditivescancausethebinder to become brittle. This research demonstrates a promising and sustainable approach to improvingpavementmaterialswhilerepurposingplasticwaste,thoughithighlightstheneed for careful optimisation of additive content.