Modification of Asphalt Pavement with Polysulfide Polymer
In petrochemical industry, the production of polyvinyl chloride (PVC) is accompanied by formation of heavy end wastes which consist of a mixture of di and multichloro compounds as kind of materials which are generated in ethylene dichloride (EDC) purifcation. A high quantity of chloro compounds found in the heavy end waste allows it to be polymerized with alkaline polysulfdes to form polysulfde polymers. Thus, according to this, the environmentally hazardous heavy ends waste can now be converted into useful polysulfde polymers without any environmental problem. There are some methods for synthesizing a polysulfde polymer (PSP) from this waste. PSP with a rubbery property can be used for modifcation of bitumen. In this research the effects of polysulfde polymer (PSP) and the polysulfde polymer prepared by heavy end waste (wPSP) on bitumen and asphalt have been studied. Samples of 1, 3, 5% of PSP and wPSP as modifers in bitumen have been prepared and their physical and mechanical properties are compared. Using this new modifer causes a fall in softening point (PSP=39.5%, wPSP=27.6%) and increase in enetration point (PSP=17.8% , wPSP=15.5%) and in asphalt mixture it causes decreases in rutting but has a small effect on Marshall strength of asphalt samples (PSP=4% , wPSP=11.6%).