Evaluación del efecto de los agregados de asfalto reciclado en las propiedades físico-mecánicas de las mezclas asfálticas en frío

Abstract

This research focused on evaluating the stability and flow of cold asphalt mixes using recycled asphalt aggregates (RAP) in the Marshall Method, with the aim of determining their technical viability as a sustainable alternative for road construction. The importance of the study lay in the need to reduce the consumption of virgin aggregates and utilize materials from the milling of deteriorated pavements, contributing to the conservation of natural resources and the reduction of environmental impacts. The methodology initially included the physical-mechanical characterization of recycled aggregates, new aggregates, asphalt cement, and asphalt emulsion using ASTM and INEN standardized tests. Subsequently, a conventional standard mix and an alternative mix with the addition of 20% RAP combined with 80% new aggregates were designed, achieving optimal particle size distribution according to the specifications of MOP-001-F-2002. In the design phase, an optimal net asphalt content of 6.0% was determined for both proposals. For the conventional mix, this represented 9.84% CSS-1h asphalt emulsion, while the recycled mix required only 8.70% new liquid emulsion due to the contribution of the pre-existing binder in the recycled material. Finally, the experimental results for stability, flow, bulk density, and voids were compared at their optimum points. The incorporation of 20% recycled aggregates resulted in a 20.03% reduction in stability and a 3.57% reduction in mix flow. Volumetrically, the addition of RAP caused a 2.3% increase in air voids, while bulk density decreased by 0.18%. It was concluded that the use of recycled aggregates in cold asphalt mixes is technically feasible and sustainable. Despite mechanical and volumetric variations, the recycled design meets the stability, flow, density, and void content requirements for the mineral aggregate established by current regulations, guaranteeing the structural integrity of the pavement and optimizing the consumption of new binder.