Effect of Liquid Waste Polysulfide and Nanoclay on Engineering Properties of Bitumen

Bitumen as a really important material road construction shows very attractive properties. Modification of bitumen by polymers increases the service life of the asphalt pavement. In order to improve the engineering properties of bitumen, both chemical and physical methods have been used which the physical methods, because of their simplicity, are more commonly employed. In physical modification, some materials such as polymers, are usually used. Polysulfide is one of the polymers that has recently attracted the interest of industries. It is interesting that this polymer which is made of heavy chlorinated petrochemical was tested to reduce the costs which are associated with bitumen modification as well as helping to alleviate the problem of waste accumulation. In this investigation, a polysulfide polymer derived from waste (waste liquid polysulfide polymer, WLPSP), in pure form and in combination with nanoclay was used to modify bitumen. The amounts of polymer added to the bitumen were 1, 3 and 5 weight percents. In the samples modified with both polymer and nanoclay, the amount of nanoclay was fixed at 2 wt%. The WLPSP polymer not only increased the softening point but also reduced the penetration of bitumen, resulting in improvement of the properties of bitumen at high temperatures. These effects could be observed for all samples of bitumen-polymer-clay and bitumen-nanoclay blends. The bitumen modified with nanoclay-polymer and nanoclay alone showed a further reduction in penetration upon WLPSP modification. The penetration index (PI) of bitumen increased, indicating a lower thermal sensitivity of modified bitumen.