Self-Healing Performance of Asphalt Concrete with Ca-Alginate Capsules under Low Service Temperature Conditions

Abstract

Calcium alginate capsules containing rejuvenators represent a promising method for asphalt concrete premaintenance, but their healing capacities under lower temperature conditions are still unknown. This paper investigated the healing performance of asphalt concrete containing calcium alginate capsules at low service temperatures. The Ca-alginate capsules were synthesized, and their morphology, compressive strength, thermal resistance, and relative oil content were evaluated. Besides, evaluations for the healing of asphalt concrete and the rejuvenator-release ratio of the capsules were determined via fracture-healing-refracture testing and Fourier-transform infrared spectrum experiments. Meanwhile, the glass transition temperature and rheological property of asphalt binder after compressive loading under different temperatures were explored via a differential scanning calorimeter and dynamic shear rheometer. The results showed that the capsules had good thermal resistance and mechanical strength. The capsules released less oil under −15, −10, and −5 ℃ than at 20 ℃, and the healing ratios of the asphalt concrete with the capsules at −15, −10, and −5 ℃ were obviously lower than that at 20 ℃. The released rejuvenator from the capsules could decrease the complex modulus and glass transition temperature of the asphalt binder. When compared with low service temperatures, the asphalt binder containing the capsules and serving at a high temperature has a better softening effect and low-temperature performance due to more oil being released.

Healing Evaluation of Asphalt Mixtures with Polymer Capsules Containing Rejuvenator under Different Water Solutions

“…Sunflower oil can assist in reestablishing the natural healing properties of aged asphalt by providing a light component [38][39][40]. Furthermore, sunflower oil exhibits a definite peak at 1745 cm −1 , whereas there is an absence of any absorption peak within the range of 1700 and 1800 cm −1 [27,28,34,41]. Consequently, FTIR spectra reveal that this unique peak (1745 cm −1 ) may be utilized to measure the rejuvenator discharge ratio of capsules within asphalt concrete following repeated loading cycles.…”

Optimised Sunflower Oil Content for Encapsulation by Vibrating Technology as a Rejuvenating Solution for Asphalt Self-Healing

“…Nowadays, capsules with polynuclear morphology have been extensively developed for asphalt self-healing purposes [ 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. This type of capsule has a spherical shape with internal cavities or pores where the oil is enclosed [ 18 , 20 ], providing a controlled release of the restoring agent once the capsule is activated allowing multiple healings on aged bitumen over time [ 19 ].…”

“…This type of capsule has a spherical shape with internal cavities or pores where the oil is enclosed [ 18 , 20 ], providing a controlled release of the restoring agent once the capsule is activated allowing multiple healings on aged bitumen over time [ 19 ]. The synthesis of polynuclear capsules can be achieved by extrusion-based methods employing dropping funnel [ 20 , 21 , 22 ] and syringe pump [ 20 , 22 , 23 ] devices. However, these methods have a drawback of lower production rates.…”