Fondecyt Regular Project. Self-healing of bituminous materials using renewable resource-based microcapsules

This study aimed to characterise polynuclear biocapsules containing low-cost rejuvenating agents for asphalt self-healing. Capsules consisted of a biopolymeric matrix of calcium alginate containing cooking oil and mineral oil as rejuvenating agents, being synthesised using ionic gelation through the pumping dripping technique. The physical-chemical properties of the oil-in-biopolymer emulsions and their stability over time were studied. The morphological and thermophysical properties of the biocapsules, as well as the encapsulation efficiency of the rejuvenating agents, were quantified and characterised by microscopic techniques and laboratory tests. Main results showed that emulsions should be used for encapsulation purposes within a period no longer than 3h, reducing the effect of instability phenomena. Besides, the biopolymer-based polynuclear capsules presented uniform size, internal multicavity microstructure resulting in high encapsulation efficiencies and thermal stability at high temperatures, proving that cooking oil and mineral oil can be potentially used as low-cost rejuvenating agents and thermally stable additives for asphalt self-healing purposes.

This paper presents the synthesis and characterization of biopolymeric capsules for asphalt self-healing, where bio-oil from liquefied agricultural biomass waste was used as an eco-friendly rejuvenating agent for asphalt materials. Bio-oil polymeric capsules were synthesized using simple dripping technique by syringe pump device, where the bio-oil was encapsulated by ionic gelation in a polysaccharide polymer matrix of sodium alginate. Morphology, thermal stability, mechanical and physical-chemical properties of bio-oil capsules and their components were evaluated. Self-healing efficiency of the bio-oil as rejuvenating agent in cracked bitumen samples was quantified by fluorescence microscopy techniques. Main results proven that the bio-oil can be diffused in the bitumen samples reducing their viscosity and consequently healing the open microcracks.