Caracterización de RAP e identificación de su influencia en el comportamiento mecánico de mezclas asfálticas en caliente

Abstract

In recent years we have sought the implementation of methods that reduce costs and environmental damage generated by different techniques of construction and road rehabilitation, within which can be found recycled asphalt pavement (RAP). The RAP is a material that daily is used in new asphalt mixes but their management has been made empirically, considering that are not known for certain properties of this because it is a highly variable material and has different characteristics depending on different factors that influence their behavior and management to obtain a specific new asphalt mix. Currently it lacks depth studies on the properties and characteristics of this material, why is not possible to unify the way of working and handling. In this research the characterization of RAP found in the city of Bogotá D.C. is made, its properties are identified and the main variations occurring between different samples is established. Later the influence of the content and degree of aging of the asphalt present in the recycled material in new asphalt hot mix with different percentages of addition thereof is identified. 6 samples of RAP were taken, 3 gathering in plant and 3 sections of different routes were taken, and the extraction of asphalt, the granulometric analysis of extracted stone aggregates, recovery asphalt by distillation with a rotary evaporator was performed and tests were applied to determine the degree of oxidation. Later RAP was manufactured in the laboratory by controlling the content of asphalt and was two degrees of aging different so similar to those obtained in the initial characterization results are represented. an optimal mix MDC-19 control by the Marshall method was designed and mixtures were prepared with addition of RAP simulated in different percentages. Finally behavior was evaluated in comparison with the optimal mixture. The characterization made shows a high degree of heterogeneity in the RAP and influence the content of asphalt and its significant degree of aging on the behavior of hot mix asphalt that it would be added, getting that hot mix asphalt with added RAP contents of high or close to that used in the optimal mix asphalt, do not meet the INVIAS standard, whereas with asphalt content in close to the average obtained in the characterization made to RAP (6.74%), all requirements are met and They presented the best mechanical conditions. Also in this research it demonstrates that methylene chloride (solvent allowed for recovery INVIAS asphalt) has effects on reclaimed asphalt, reducing its stiffness and increasing its fluidity. It also shows that procedures STOA (Short Term Aging Oven) and LTOA (Long Term Aging Oven) allow to obtain aged mixtures similar to the actual conditions. In conclusion the results of this research serve as a guide for based on certain properties of the RAP, can select appropriate new materials and recycling proportions, to obtain resulting blends with good mechanical behavior and comply with the INVIAS requirements of the standard.