by Jorge Luis Argoty Burbano*, Gabriel Alexander Burbano Villarreal
ABSTRACT
The durability of flexible pavements in high Andean altitude areas requires asphalt mixtures with superior resistance to plastic deformations. This study comparatively evaluates the performance of conventional hot dense asphalt mixtures (MDC-2) versus mixtures modified with recycled polypropylene fibers, using Marshall design. Aggregates from the San Francisco quarry (Putumayo, Colombia) and asphalt from the Barrancabermeja refinery were used. The methodology included metrological calibration of the Marshall press (R² ≈ 1.00) and comprehensive characterization of aggregates according to INVIAS standards. The results show that the addition of polypropylene fibers significantly reduces the Marshall flow from 3.1 mm to 2.7 mm (reduction of 12.9%, p < 0.05), indicating greater resistance to plastic deformations. Marshall stability did not present significant differences (p > 0.05): 1351 kg (conventional) versus 1360 kg (modified). The asphalt content decreased from 6.1% to 5.75% (0.35 percentage points), while the filling-binder ratio improved from 0.98 to 1.20, evidencing better cohesion and adhesion. The volumetric parameters remained within specifications: empty air (3.6%-4.0%), empty mineral aggregate (14.80%-17.15%) and empty empty filled with asphalt (77.5%-87.2%). These findings demonstrate the technical feasibility of mixtures reinforced with recycled polypropylene for high-traffic road infrastructure, with the potential to extend the useful life of the pavement by reducing plastic deformations.
