Characterization of Asphalt Binder Containing Microcapsules

Öz

Asphalt pavements are exposed to traffic loading and adverse environmental effects such as rain and oxidation which result in decreasing their relaxation capabilities and the initiation of cracks. Recent research highlights the importance of developing long life pavements. One of the possible ways is to utilize innovative maintenance techniques such as self-healing technologies in order to reverse the aging process in asphalt binder. So as to achieve this goal, self-healing microcapsules seems to be an effective way to autonomously repair the micro-cracks, restore original mechanical properties, then further slow fatigue cracks growth and increase the fatigue life of the pavement. In this study urea formaldehyde (UF) self-healing microcapsule were prepared by in-situ polymerization method. Following the characterization of microcapsules, different amount of microcapsules (6, 8, 9 ,10, 11 and 12%) were added into bitumen. Rheological properties of the samples have been determined by means of Dynamic Shear Rheometer. Ductility test was also employed to characterize the mechanical properties of the bitumen samples. Based on results the produced microcapsules can endure high temperatures, which indicate that these microcapsules can resist the thermal influence of bitumen in application. Besides, bitumen samples involving microcapsules exhibit satisfactory results in terms of complex modulus (G*) and bitumen recovery tests. The recovery value of the modulus increased first and then decreased with the amount of microcapsules. Microcapsules containing rejuvenator will be a promising product to realize the smart pavements.

Anahtar Kelimeler

• Bitumen
• Self-healing
• Microencapsulation
• Rejuvenator

Characterization of Asphalt Binder Containing Microcapsules

Öz

Asfalt kaplamalar, trafik yükleri, yağmur ve oksidasiyon gibi yol kaplamaları için olumsuz çevresel etkilerine maruz kalarak mekanik özelliklerini kaybetmektedir. Son zamanlardaki araştırmalar uzun ömürlü kaplamaların önemini vurgulamaktadır. Sürdürülebilirlik kapsamında bitümlü sıcak karışımlarının ömrünü korumak ve arttırabilmek amacı, asfalt endüstrisini farklı araştırmalara itmiş ve günümüzde “kendi kendini iyileştiren” (Self Healing) teknikler üzerine yoğunlaştırmıştır. Bu hedefe ulaşmak için, kendi kendini onaran mikrokapsüller, mikro çatlakları otonom olarak onarmanın ve orijinal mekanik özellikleri geri kazanmanın, daha sonra mikro çatlaklarının büyümesini daha da yavaşlatmanın ve kaplamanın ömrünü uzatmanın etkili yöntemlerden biri olarak görünmektedir. Bu çalışmada, üre ve formaldehit (UF) karışımı ile kendi kendini iyileştiren mikrokapsüller, in situ polimerizasyon yöntemi ile hazırlanmıştır. Mikro kapsüllerin karakterizasyon araştırılması ve asfalt içinde gösteren iyileşme oranını incelemek amacı ile bitüm içine farklı miktarda mikro kapsül (6, 8, 9 ,10, 11 ve %12) eklenmiştir. Numunelerin reolojik özellikleri Dinamik Kesme Reometresi ile incelenmiştir. Ayrıca mikrokapsül içeren bitüm numunelerinin mekanik özelliklerinin tespiti için çekme testi yapılmıştır. Üretilen mikro kapsüller uygulamada bitümün termal etkisine dayanabileceğini gösteren yüksek sıcaklıklara dayanabilmektedir. Ayrıca, mikro kapsülleri içeren bitüm numuneleri, kompleks modülü (G *) ve bitümün mekanik özellikleri açısından tatmin edici sonuçlar göstermektedir. Araştırmaya göre İyileşme değeri ilk etapta artıyor ve bu mikrokapsüllerın asfalt malzemesinin mekanik özelliklerini geri kazanma göstergesidir. İyileştirici madde içeren mikro kapsüller, yeni nesil kaplamaları gerçekleştirmek için umut verici bir ürün olacaktır.

Anahtar Kelimeler

• Bitumen
• Self-healing
• Microencapsulation
• Rejuvenator
• In-situ polymerization

Kaynakça

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