Examinando por Autor "Reyes-Lizcano, Fredy Alberto"

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  • Miniatura
    PublicaciónAcceso abierto
    Caracterización dinámica de una mezcla asfáltica sometida a las condiciones ambientales de Bogotá
    (2013-11-21) Rondón-Quintana, Hugo Alexánder; Reyes-Lizcano, Fredy Alberto; Vacca-Gámez, Hermes Ariel
    The paper presents the evolution of the resilient modulus, permanent vertical deformation, and fatigue law of hot mix asphalt (HMA) when exposed to the weather conditions in the city of Bogotá D.C. (Colombia) for 29 months. The trend of mixture with the exposure time is to experience an increase in stiffness values, mainly due to age-hardening process of the asphalt binder. This increase in stiffness creates increased resistance to permanent deformation and decrease in fatigue life of the analyzed mixture. Based on the resilient modulus evolution with time of exposure to the environment an equation to predict approximately the change for the fatigue life of the mixture is proposed.
  • Miniatura
    PublicaciónAcceso abierto
    Determinación de las fracciones SARA de asfaltos colombianos envejecidos al medio ambiente empleando cromatografía líquida en columna
    (2013-11-12) Reyes-Lizcano, Fredy Alberto; Daza, Carlos Enrique; Rondón-Quintana, Hugo Alexánder
    In this paper, we present a method based on liquid chromatography column to quantify the chemical composition of asphalt cements manufactured in Colombia, under the environment by determining the SARA fractions. The method was applied to thin layers of asphalt 60/70 and 80/100 to determine changes in the chemical composition of the material after exposure for 12 months in the weather conditions in the city of Bogotá; SARA tests were performed to the original asphalt, 1, 3, 6, 9 and 12 months aged respectively. SARA trials showed that aging caused a decrease in the fraction of aromatics and asphaltenes increased compared to non-aged asphalt. The reduction of aromatics and resins could be responsible for the hardening observed in the asphalt, which had a stiff and brittle consistency; that leads to obtaining higher colloidal index. The performed method established possible correlations between the chemical composition of asphalt and its mechanical properties