Properties of Ca-alginate capsules to maximise asphalt self-healing properties

摘要

Asphalt mixture is a self-healing material, which implies that its cracks can close autonomously. The limitation is that the self-healing occurs very slowly, and cracks tend to open faster than they close. To improve the self-healing rate, encapsulated oil has been added to the asphalt mixture. When the capsules rupture, the oil is released, which promotes the filling of the cracks by bitumen. Properties such as the internal structure, composition and size of the capsules, may influence their rupture. This paper focuses on sunflower oil encapsulated in a porous calcium-alginate structure; the influence of capsules & rsquo; (i) strength and (ii) size in their compressive strength and, the influence of the capsules & rsquo; (i) thermal expansion, (ii) thermal resistance and, (iii) internal structure, in the release of the oil have been analysed. The results showed that the strength of the capsules was influenced by the pore size of the calcium-alginate structure, that the capsules could resist the temperature that is reached during asphalt mixing and compaction and, that approximately 50% of the oil may not be released during self-healing.(c) 2021 Elsevier Ltd. All rights reserved.