Study On The Gilsonite/Polymer Asphalt Modifiers

Asphalt has been used as an important material in road construction for more than 100 years. There are abundant resources of gilsonite at Xinjiang Karamay, Sichuan Qingchuan, Gansu and other places of China. To research the proper preparation method and properties of the gilsonite/polymer modiferd asphalts is very important to make good use of gilsonite resources and develop new kind of asphalt modifiers which can be used more convinently.The proper preparation method, properties and influencing factors of the gilsonite/polymer asphalt modifiers and modified asphalts were studied in this paper. It was shown that:1. SBS and PE are most suitable to compound with gilsonite to prepare the asphalt modifiers within the common elastomers and plastic materials.2. Gilsonite/polymer asphalt modifiers could be prepared by different ways which prepared by the Banbury mixer has the best properties. The best technological condition of modified asphalt preparation is to stir about 1 hour at 170-180℃. When preparing the modified asphalts, the phase uniformity of the modified asphalt will be better if the asphalt were feeded to the asphalt modifiders by 4 steps than by one step.3. Star-type SBS with S/B(30/70) is best to compound with the gilsonite to prepare the asphalt modifiers. Gilsonit content in gilsonite/SBS asphalt modifiers should be within 40%. The dispersity of SBS in asphalt could be improved by adding high aromatic oil, naphthenic oil or carbon black. The modified asphalt has better high-temperature behavior when high aromatic oil proportion greater than 10%. The properties of gilsonite/SBS modified asphalts are the best when the proportion of carbon black is around 10%.4. Compared with HDPE and LLDPE, LDPE is more suitable to compound with the gilsonite. The ductility of the modified asphalts has a maximum when the content of gilsonite is between 40% to 60% in gilsonite/LDPE modifiers. The properties of gilsonite/LDPE modified asphalts are the best when the content of DCP and MAH is between 0.04-0.06% and 1.0-1.5%.5. The asphalt modifiers with more than two polymers would have better modifying effects. And some recycled materials could be compounded with gilsonites to make the asphalt modifiers which also show good performences.