The effect of SBS based polymer modified bitumen and bituminous mixtures on the performance of pavements

In our country in which ninety percent of transportation is carried out by highways, nowadays axle loads are becoming heavier and traffic is rapidly increasing, hence the traditional pavements have been losing their efficiency day by day. This efficiency loss of traditional pavements forced the pavement engineers to search new methods to improve the properties of pavements. This thesis is emphasized on, one of those methods which have the most use in our country, modification. In the modification of the bitumen an SBS based polymer, one of the frequently used modifiers in our country, is chosen as the additive. The main purpose of this thesis is to determine the optimum usage percentages of this SBS based additive. In the consequence of adding 2%, 3%, 4%, 5% and 6% SBS based polymer by weight to pure bitumen, five different types of modified bitumen samples has been produced. Penetration, softening point, thin film oven, penetration after thin film oven, softening point after thin film oven and storage stability tests were performed with these modified bitumen samples and pure bitumen. 54 HMA (hot mix asphalt) samples were produced with pure and modified bitumens. One third of these briquettes were exposed to short term ageing process, one third were exposed to long term ageing process. Afterwards all of the samples were subjected to the indirect tensile strength test. With results examined, affects of the additive on bitumen has been researched and depending on the laboratory test results, performance analysis of the obtained modified bitumen has been performed at the chosen mixing percentages of the additive. Keywords: Polymer Modified Bitumen, SBS, Rheology