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Volume 18, No. 31Journal 31

DOI:https://doi.org/10.15517/envy2963

Published November 5, 2025

Scientific Papers

  1. YelitzA Ayala del Toro, Paul Garnica Anguas, Horacio Delgado Alamilla (Author)

    Effect of Temperature on the Fatigue Evaluation of Asphalt Binders

    The fatigue cracking is one of the most common distresses in flexible pavements, which is characterized by the connection of longitudinal and transverse cracks caused by the tensile stresses generated in the base of the asphalt layer, produced by the heavy traffic loads. This study evaluates the influence of temperature on fatigue failure in asphalt binders, according to two test methods: PG Grade and the Linear Amplitude Sweep (LAS) test. The research evaluates three asphalt binders, which correspond to three different applications in the asphalt mix: PG64-16 (conventional mix), PG76-16 (modified mix with polymer SBS) and PG88-22 (warm mix). The results show the difference in behavior of the binders when evaluated at different temperatures (37, 34, 28, and 20 °C) considering two types of aging: short and long term. Additionally, the transition temperature between the solid-elastic and the liquid-viscous part of the binder is explored, as a parameter for selecting a suitable temperature for the fatigue test. The results indicate a variation in the trend of the binder with most resistance to fatigue failure, with the change in temperature, particularly when the asphalt is subjected to temperatures above or below its transition point (temperature). According to the fatigue evaluation in the asphalt mixture, the transition temperature seems to be a good criteria to select an adequate temperature to evaluate fatigue in asphalt binders; nevertheless, additional validations with different materials must be done to support the results.

  2. Sandra Elodia Ospina Lozano, Lucio Guillermo López Yépez, Jeinner Arley Carrillo Carrillo, Leidy Johanna Díaz Garzón (Author)

    Effect on Flexural Strength in Concrete Modified with Recycled Concrete

    The current need for alternatives to reduce the environmental impact by increasing quarrying and use the resulting materials demolition processes, this paper the results are presented in different replacing traditional types of concrete on them, added resulting from the process of recycling concrete. 
    To develop this work the water / cement ratios were varied and steel fibers are added in different percentages, leading to obtain direct effects on physical and mechanical properties of concrete studied; as a result of the investigation it was found that a design can be made of traditional concrete mixture a decrease in resistance factor ranging from 50% to 75 % of the expected resistance, for this test standard ASTM was used C39- ASTM C78 (NTC 6731 and INV e -414 to 073).

  3. Natalia Pérez García, Paul Garnica Anguas, Delwyn Fredlund, Miguel Angel Reyes Rodríguez, Humberto García Cruz, Rodrigo Pérez Luis (Author)

    Compaction and mechanical properties of soils compacted in the gyratory compactor

    The authors present a series of compaction curves obtained in fine-grained soilsthrough use of a gyratory compactor. The effect on compaction curves of variables such as vertical pressure, angle of gyration, and speed of gyrationis shown. The curves obtained with the gyratory compactor were compared with those obtained using traditional methods of compaction (Proctor standard and modified compaction). It was observedthat the standard compaction curve can be obtained with 200 gyrations, 1.25 degrees of angle of gyration, and a vertical pressure of 200 kPa.On the other hand, with the combination of variables studied in this research, modified compaction curvescould not be reached. Tests were also performed to measure resilient modulus and unconfined compression strength onspecimens prepared at optimum compaction conditions, 2% below the optimum and 2% above the optimum (for Proctor standard tests) using two methodsof compaction.The results indicate that unconfined compressionstrengths and resilient modulus are related to the compaction method when samples are compacted at water content below optimum.

  4. Greivin Picado Muñoz (Author)

    Development of deterioration curves for flexible pavement and uncertainty factor

    Due to planning issues in the Local Road Network of Costa Rica, an important amount of roads have an advanced level of distress and receive inappropriate maintenance activities, which implies a high cost for local governments. This is because several of the Road Management Units do not have the studies and basic information needed to generate the deterioration curves that would allow to identify the state of the roads.

    The following project seeks to make an assessment of the roads in the Metropolitan Area, in the provinces of San José, Alajuela, Cartago and Heredia; in order to recognize the roads’ condition and develop the deterioration curves from the information collected in field.

    The ASTM D-6433 Standard was applied for the field condition survey of the distress and the calculating of the Pavement Condition Index. Next, the deterioration curves where created by using a multivariate statistical analysis of the data obtained.

    Having found the deterioration curves and the equation that includes the uncertainty factor, an useful tool is obtained, which can generate a deterioration model of the roads, allowing the department in charge to establish the optimal timing of pavement preventive maintenance, the adequate maintenance activities according to the level of distress and a proper distribution of the public resources.

  5. Adriana de Jesús García (Author)

    Micromechanical analysis of asphalt behaviour

    Recent theories asphalt classified as a continuous matrix, which associations of polar molecules (asphaltenes and resins) dispersed in a fluid of molecules of lower molecular weight and polarity (aromatic and saturated). To better understand the behavior of asphalt a literature review, where it was observed that the most innovative methodology is the application of atomic force microscope, which allows to characterize materials nanomechanical scale was performed.

    AFM technique has been used in the last 20 years as one of the tools that combines the powerful capabilities of the latest generation of devices with atomic force spectroscopy full range of imaging modes available on its measurement: contact, noncontact and down force. Following this, they have achieved excellent results in the morphology of the asphalt binder, where different researchers have come to characterize a multi-phase asphalt defined as: to stage the katana-phase, perfase and salt-phase. The literature review was conducted in order to enrich the knowledge of the micromechanical behavior of asphalt binder, which then serve as the basis for determining and applying the indentation technique, which involves determining the value of stiffness modulus. Therefore micromechanical behavior analysis is an important tool for future research, which should focus on analyzing the properties of asphalt binder.