بررسي خواص ويسكو‌الاستيك قير اصلاح شده با نانو لوله كربني

Viscoelastic Analysis of the Bitumen Modified by Carbon Nanotubes

قير در دماهاي بالا يك سيال نيوتني است، اما در دماهاي پايين، يك سيال ويسكو الاستيك است كه ناحيه ويسكوالاستيك خطي آن، مقاومت قير نسبت به بار ترافيكي را نشان مي دهد. در اين تحقيق از نانو لوله‌ كربن به عنوان يكي از اصلاح كننده هاي خواص ويسكو الاستيك قيراستفاده شده است. بر روي نمونه هاي خالص و اصلاح شده با نانو لوله هاي كربني، آزمايشهاي اوليه قيرها (مانند: نقطه نرمي، درجه نفوذ و....)،آزمايش پرتو ايكس1 (XRD) و همچنين آزمون‌هاي ريولوژيكي با بكارگيري دستگاه ريومتر برشي ديناميكي2 (DSR) انجام شد. استفاده از نانو لوله كربن به عنوان افزودني باعث افزايش نقطه نرمي، كاهش درجه نفوذ، كاهش حساسيت رطوبتي و همچنين بهبود مشخصات عملكردي قير نسبت به قير پايه شده است. در پايان، با تحليل منحنيهاي مرجع مدول الاستيك، مدول مختلط، مدول اتلاف و زاويه تاخير فاز، مشاهده مي شود كه ويژگيهاي ويسكو‌ الاستيك قير اصلاح شده، بهبود يافته است.

Bitumen is a Newtonian fluid at high temperatures but a viscoelastic fluid at other temperature ranges, that its linear viscoelastic area shows bitumen resistance toward traffic load. In this study, carbon nano-tube, as bitumen viscoelastic characteristics modifier, is employed. Then classical experiments of bitumen (such as:softening point, penetration and etc..), X- ray diffraction and rheological tests using dynamic shear rheometer (DSR), also were done on modified samples. Using carbon nano tubes as bitumen modifier cause the significant improvement on classical properties of bitumen and also on performance characteristics of bitumen according to the base bitumen. Finally, by analysis the Master curves of complex modulus, loss modulus, storage modulus and phase angle, it is observed that viscoelastic characteristics of modified bitumen has improved significantly. With the increase of traffic and consequently, the loads applied on the roads, the need for a more durable pavement has gained special significance. Therefore, the researchers have been seeking to improve the functional properties of bitumen and asphalt. Nanotechnology deals with the creation and use of functional materials, devices, and systems with novel properties and functions that are achieved through the control of matter at the atomic and molecular level. Among various nano-size materials, carbon Nanotubes (CNTs) may represent the most promising modifier for the improvement of performance characteristics of structural and construction materials. CNTs have been extensively used as the reinforcing agents for high performance polymer composites. It has been reported that the incorporation of CNTs in the polymer matrix results in a significant improvement in the mechanical, electrical and thermal properties of the polymer matrices. Nowadays, a lot of rheological evaluations are carried out, polymer modified bitumen and the purpose of all, are the conditions that can simulate actual operating conditions of bitumen that equals to pavement condition.