Examinando por Autor "Rondón-Quintana, Hugo Alexánder"

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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
  • Miniatura
    PublicaciónAcceso abierto
    Evaluación del comportamiento de arcillas sometidas a diferentes tiempos de exposición a altas temperaturas
    (2013-11-15) Rondón-Quintana, Hugo Alexánder
    Laboratory tests were performed in order to evaluate the effects on the index properties, volumetric behavior and monotonic uniaxial strength of two clays caused by the application of different temperatures (150, 225 and 300 °C) for varying periods of time (1, 7 and 15 days). Additionally, we studied whether the clays recover the mentioned properties after being subjected to high temperatures and being again exposed to room temperature for one week in the laboratory. The mean objective of this research project is to evaluate whether the application of increasing temperatures in clays can be a good stabilization method in the future or if it is possible to produce mineral filler. Results show that the plasticity, expansion potential and monotonic uniaxial strength decrease when the temperature is raised up 150-300 °C on the samples and when the exposure time increased. Additionally, it is reported that the recovery of clay properties is zero when they are subjected to 300 °C for 15 days.