Multi-scale study of bio-binder mixtures as surface layer: Laboratory evaluation and field application and monitoring

Abstract The potential use of bio-binders as full or partial substitutes of petroleum-based binders have gained interest from the paving researches in recent years. Although there are many studies about rheological characterization of alternative binders, there is still lack of knowledge about mixtures and field performance of this type of materials. In this sense, this paper presents an evaluation of bio-binder produced from vegetal biomass, by-product of the treatment of pine wood resin, as the total substitute of the asphalt binder for surface pavement layer, comparing its performance with a neat asphalt binder, used as reference, at three study levels: binder evaluation, mixture evaluation and field performance monitoring. Linear viscoelastic characterization, permanent deformation and fatigue responses were studied for the binders. The mixtures designed with both binders were tested in terms of stiffness, moisture sensitivity and permanent deformation. The performance in the field test sections was monitored during three years by structural evaluation (FWD) and roughness test (IRI). Results showed that the bio-binder studied presented acceptable behavior, with similar responses of that exhibited by the petroleum-based asphalt binder. The bio-binder studied could be used as binder in mixtures for surface layers of road pavements, however, the durability of that type of mixtures and the environmental impact of the production process need to be further studied in order to complement the feasibility of this alternative as a sustainable solution.