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Volume 17, No. 30Journal 30

DOI:https://doi.org/10.15517/3sf94283

Published November 5, 2025

Scientific Papers

  1. Daniela Araya Gamboa, Roberto Salom Pérez (Author)

    Identification of fauna crossing sites on the 415 route, in the "Paso del Jaguar", Costa Rica.

    The Jaguar Corridor Initiative aims to maintain the connectivity of this species. In Costa Rica, this initiative started on the Barbilla-Destierro Biological Subcorridor. The future paving of a road as an offset measure of Reventazon Hydroelectric Project was identified as a potential barrier forthe connectivity of the jaguar (Panthera onca) and other animals. In this study we suggest a method that can be used to identify animal crossing points on a gravel road. Data was collected from June 2011 to January 2012. We made a comparison between gravel and paved sections of the same road. To identify animal crossing sites and sectors, information from surveys, interviews and structural connectivity was overlapped. When comparing the gravel and paved sections, the paved section had more cars using it, more houses at its edges, more wildlife roadkills and fewer sightings and species. Three wildlife crossings sites and five sectors were identified. Jaguar and margay (Leopardus wiedii) were registered crossing the road, and raccoons (Procyon lotor) frequently used a culvert as an underpass. This methodology may be used as a practical tool that can be implemented by government and enterprises to identify wildlife crossing sites and to recommend mitigation actions that would reduce the impact caused by the creation and improvement of roads in the region.

  2. Gabriel Chaves Flores, Henry Hernández Vega (Author)

    Transit performance and quality of service indicators for transit services for students to the Universidad de Costa Rica

    This paper presents a methodology to evaluate an university bus transit service. Both performance and quality of service indicators were applied in the system evaluation to analyze the mobility of students and staff at the main campus Rodrigo Facio of the University of Costa Rica (UCR), who daily commute using a special bus transit service. Over one third of the total trips to the campus are made by this special bus transit service provided by the university; which implies that the quality of the mobility of more than 10 thousand people depends on this service. Information related to the performance and quality of service of the bus transit system is a fundamental input for future university transportation master plans. On an average weekday more than 350 trips are made by the exclusive bus transit service, including trips that depart and arrive to the main campus Rodrigo Facio; therefore the need to offer a high-quality service in order to increase ridership, and thus, to help to generate a more pleasant and healthier environment. Relevant issues that affect users were identified. Also, the methodology was applied to assess the system through different performance indicators. Finally, the main findings include potential new bus transit routes and a list of countermeasures, ranked according to the priority given by the users to improve the quality of the service.

  3. Natalia Perez Garcia, Delwyn Fredlund, Paul Garnica Anguas, Noe Mestas Martinez (Author)

    A model to predict changes in resilient modulus resulting from wetting and drying

    The resilient modulus of a soil is an important parameter needed for pavement design. However, this parameter experiences post-compaction seasonal changes during the service life of the pavement as a result of wetting or drying of the soil during dry or rainy periods. Variations in the resilient modulus should be introduced into pavement design methodologies. Research literature shows resilient modulus results from other countries; however, the information is scarce for Mexican soils. In this paper, the authors show results of a research carried out in the laboratory to evaluate a model for the prediction of the effect of wetting and drying on the resilient modulus of soils classified as clays, silt, and sand. Several samples were prepared at optimum conditions using the Proctor standard test. Some specimens were then dried by allowing a loss of water through evaporation while others were allowed to gain water through capillarity (assumed to simulate post-compaction conditions). After the samples were conditioned to new water contents, resilient modulus tests were performed following the NCHRP 1-28A protocol. The results show that the resilient modulus can be predicted using a model which is a function of the deviator stress and confining pressure (i.e., (sd/s3) and the variation of water content from optimum water content conditions (i.e., the condition after field compaction). The R2 results when using the proposed resilient modulus model was 84.1%.

  4. Ana Sofía Figueroa Infante, Fredy Alberto Reyes Lizcano (Author)

    Moisture damage analysis for an asphalt mixture through the MIST test and the iPAS 2D® software

    Moisture Damage is one of the most common problems in asphalt pavements roads in tropical countries and in areas exposed to prolonged periods of rain. This research presents the results of moisture damage in a dense asphaltic mixture, which was designed by the Superpave® methodology and manufactured with eight types of asphalt, subjected to a controlled process of oxidation. In addition, the results of the performance of the asphalt mixture and their relation with moisture damage in Moisture Induced Sensitivity Test-MIST and its analysis using the iPAS 2D® software, which was developed by the MARC Group from the University of Wisconsin-Madison and led by the Professor Hussain Bahia.  The results indicate a higher loss of tensile strength when the mixtures are tested with the MIST test compared with the Tensile Strength Ratio-TSR test.  Similarly, the images analysis shows the evolution of loss of contact of the aggregates according to the different periods of oxidation of the asphalts and its relation with the MIST analysis.

Literature Review

  1. Marianela Espinoza Alfaro (Author)

    Bonded concrete overlays as a rehabilitation alternative for asphalt pavements

    The main objective of this study, is to present basic considerations while designing a concrete overlay as a rehabilitation alternative for existing pavements. First, the pavement condition has to be evaluated by determining the type of damage, previous repairs, and the need for surface preparation; then it is necessary to evaluate the possibilities for the application of this technique. Bonded concrete overlays are a sustainable strategy to preserve and extend the life of pavements that can be used as minor rehabilitation, which its main purpose is to add structural capacity and to eliminate surface damage on existing pavements by creating an adequate bond between the concrete overlay and the pavement structure. High deterioration levels have been identified on pavement structures in Costa Rica, which make up most of the roads in the national road network, where quite often feasible solution alternatives are not considered due to a lack of knowledge. Therefore, this literature review focuses on the use of bonded concrete overlays, considering the construction requirements, as well as the design methodologies. This paper intends to provide road engineers with a reference document to help in deciding the most adequate solution to common problems found on existing pavements, in order to increase knowledge in this area, to encourage the use of new techniques to improve road infrastructure, therefore improve the quality of service provided to the user.